JP2673819B2 - Optical recording material containing imidazole dye - Google Patents

Description

TECHNICAL FIELD The present invention relates to an optical recording material using a laser,
More specifically, it relates to an optical recording material using an imidazole dye as a recording medium for laser light.

BACKGROUND OF THE INVENTION Recently, optical recording using a laser has been actively researched and developed because it enables recording, storage and reproduction of high density information.

An optical disc can be given as an example of the optical recording.

In general, an optical disc records information at a high density by irradiating a thin recording layer provided on a circular substrate with a laser beam focused to about 1 μm. The recording is performed by causing changes such as decomposition, evaporation, sublimation and dissolution of the recording layer which has absorbed the energy of the irradiated laser beam.

Further, the recorded information is reproduced by irradiating the laser light to the extent that the recording layer is not changed, and reading the difference in reflectance between the changed portion and the non-changed portion of the recording layer.

Therefore, as an optical recording material, it is necessary to efficiently absorb the energy of the laser light, so that the absorption of the laser light of a specific wavelength used for recording is large, and the reproduction of information is accurately performed. It is necessary that the reflectance with respect to the laser light of the specific wavelength used is high.

Various kinds of optical recording materials of this type are known. For example, JP-A-55-97033 discloses a substrate in which a single phase of a phthalocyanine dye is provided. However, phthalocyanine dyes have a problem that they cannot be coated by coating because they have low sensitivity to laser light and low solubility in organic solvents.

Further, JP-A-58-83344 discloses a recording layer provided with a naphthoquinone dye. However, while such a dye has the advantage of being easily deposited, it has a low reflectance, and the contrast relating to the reflectance between the portion recorded by the laser beam and the unrecorded portion is low, and the reproduction of the recorded information is reduced. Will be difficult. Further, organic dyes generally have a problem of poor storage stability.

Therefore, the present inventors, as a result of continuing various research in order to search for a dye having good characteristics for laser light,
As a dye suitable for laser light recording, a imidazole dye was found out of many dyes, and the present invention was completed.

Object of the invention The object of the present invention is an optical recording containing an imidazole dye, which has a high solubility in an organic solvent, can be coated by coating, and has a high reflectance, a good contrast and an excellent storage stability. To provide the material.

Therefore, the above object of the present invention has been achieved by an optical recording material having an imidazole dye represented by the general formula [I].

General formula [I] [In the formula, R ₁ and R ₂ each represent a hydrogen atom, an alkyl group or a substituted alkyl group, and R ₁ and R ₂ are bonded to each other to form 5
You may form a membered ring or a 6-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 tube by a carbon atom, a nitrogen atom, an oxygen atom or a sulfur atom. Further, the above object of the present invention is to provide an optical recording material comprising a recording layer and a substrate for recording by changing a state by a laser beam, wherein the recording layer contains an imidazole-based compound represented by the general formula [I]. Achieved by an optical recording material containing a dye.

 Hereinafter, the present invention will be described in more detail.

In the imidazole dye represented by the general formula [I], R ₁ and R ₂ are preferably a hydrogen atom, an alkyl group, and a substituent such as a hydroxyalkyl group, an alkoxyalkyl group, a lucoxyalkoxyalkyl group and an alkylsulfonamidoalkyl group. It is an aalkyl group. Examples of these groups are methyl, ethyl, propyl, isopropyl, sec-butyl, butyl, isobutyl, t-butyl,
C1-C18 alkyl groups such as octyl, dodecyl, octadecyl, cyclohexyl, etc., and substituted alkyl groups such as hydroxyethyl, methoxyethyl, methoxybutyl, ethoxyethyl, methoxyethoxyethyl, ethoxyethoxyethyl, β-methanesulfonamidoethyl, etc. Is mentioned.

Examples of the 5- or 6-membered ring formed by combining R ₁ and R ₂ include pyrrolidino, piperidino, piperazino, morpholino and other groups.

R ₃ , R ₄ , R ₅ and R ₆ may be the same or different from each other, preferably a hydrogen atom, a halogen atom, an alkyl group, a hydroxyalkyl group, an alkoxyalkyl group, an alkylsulfonamidoalkyl group, an alkoxy group, amino. Group, alkyl-substituted amino group, dialkyl-substituted amino group, aryl-substituted amino group, and the like. Examples of these are chlorine atom, bromine atom, methyl, ethyl, hydroxymethyl, hydroxyethyl, methoxyethyl, methanesulfonamidoethyl, methoxy, ethoxy, N-methylamino, N-methylamide, sulfoneamino, acetylamide and the like. Groups.

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

As the organic group by a carbon atom, an alkyl group (for example, methyl, i-propyl, t-butyl, trifluoromethyl, benzyl, 3- (4-aminophenyl) propyl, allyl, 2-dodecyloxyethyl, 3-phenoxy) is used. Propyl, 2-hexylsulfonylethyl, 3- [4
-(4-dodecyloxybenzene) sulfonamidophenyl] propyl, 1-methyl-2-[(2-octyloxy-5-t-octylphenyl) sulfonamidophenyl] ethyl, 1-methyl-2- [2-octyl Oxy-5- (2-octyloxy-5-t-octylphenylsulfonamide) phenylsulfonamide] ethyl,
2- [2-octyloxy-5- (2-octyloxy-5-t-octylphenylsulfonamido) phenylsulfonamido] ethyl, etc.), aryl group (for example, phenyl group, naphthyl group, substituted phenyl group, substituted naphthyl) A group is preferable, and examples of the substituent include a halogen atom (preferably fluorine, chlorine, bromine), a cyano group, a nitro group, a carboxyl group, an optionally substituted alkyl group, an alkoxy group, an alkylamido group, and aryl. Amido group, alkylsulfonamide group, arylsulfonamide group, carbamoyl group, sulfamoyl group, dialkylcarbamoylamino group, dialkylsulfamoylamino group; arylcarbamoylamino group, alkyloxycarbonylamino group, imide which may be each substituted. Group · The carbamoyl group, an alkylsulfamoyl group, an arylcarbamoyl group, an arylsulfamoyl group, an alkoxycarbonyl group and a group as such alkoxysulfonyl.

Explaining each of these substituents in more detail, examples of the unsubstituted alkyl group include methyl, ethyl and sec.
-Butyl, t-octyl, dodecyl, etc. are preferably a linear or branched alkyl group having 1 to 22 carbon atoms, and the substituted alkyl group is represented by a hydroxyethyl group, a hydroxy group substituted with a hydroxy group, methoxyethyl, Alkoxy-substituted alkyl groups represented by methoxyethoxyethyl groups are preferred.

Examples of the unsubstituted alkoxy group have 1 to 1 carbon atoms represented by methoxy, ethoxy, n-butoxy, sec-butoxy, dodecyloxy group, octadecyloxy and the like.
22 linear or branched alkoxy groups are preferable, and the substituted alkoxy group is preferably an alkoxy-substituted alkoxy group represented by methoxyethoxy and the like.

The unsubstituted alkylamide group is preferably an amide group of an alkane having 1 to 22 carbon atoms represented by acetamide, propionamide, pentanamide, laurylamide, stearylamide and the like, and as the substituted alkylamide, 2,4- Di-t-amylphenoxyacetamide, 2
Phenoxy-substituted alkylamide groups represented by-(m-pentadecylphenoxy) butanamide and the like, and halogen-substituted alkylamide groups such as chloroacetamide, trifluoroacetamide and perfluorobutanamide are preferable.

As the arylamide group, an unsubstituted arylamide group such as benzamide and naphthamide, an alkoxy-substituted benzamide group represented by o-tetradecaoxybenzamide, m-laurylamide benzamide, m- {2
-(2,4-di-t-amylphenoxy) hexanamide} benzamide, amide represented by o-hexadecanesulfonamidebenzamide, etc., halogen represented by sulfonamide-substituted benzamide, o-chlorobenzamide, perfluorobenzamide, etc. Substituted benzamide groups are preferred.

As the alkylsulfonamide group, methanesulfonamide, ethanesulfonamide, butanesulfonamide,
A sulfonamide group of an alkane having 1 to 22 carbon atoms represented by hexadecane sulfonamide and the like is preferable.

Representative examples of the arylsulfonamide are unsubstituted arylamide groups such as benzenesulfonamide and naphthalenesulfonamide, and p-toluenesulfonamide, xylenesulfonamide, dodecylbenzenesulfonamide, p-dodecyloxybenzenesulfonamide and the like. An alkyl-substituted benzenesulfonamide group and an alkoxy-substituted benzenesulfonamide group are preferable as the substituted benzenesulfonamide group.

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 having 1 to 4 carbon atoms are typical and preferable. .

As the arylcarbamoylamino group, an unsubstituted phenylcarbamoylamino group of a phenylcarbamoylamino group, a halogen-substituted phenylcarbamoyl group represented by p-cyanophenylcarbamoylamino or p-chlorophenylcarbamoylamino, and the like are preferable as the substituted phenylcarbamoyl group. .

The alkyl of the alkyloxycarbonylamino group has 1 carbon atom such as methyl, ethyl, butyl and dodecyl.
Substituted alkyl of -22 is preferable, and as the imide group, succinimide, phthalimide, and alkyl-substituted products thereof are preferable.

Alkylcarbamoyl group, alkylsulfamoyl group as alkyl include butyl, dodecyl, etc.
Alkylcarbamoyl group or alkylsulfamoyl group having an unsubstituted alkyl group such as 22 alkyl group, γ-
A phenoxy-substituted alkyl group such as (2,4-di-t-amylphenoxy) butyl, a substituted alkylcarbamoyl group or a substituted alkylsulfamoyl group having an alkoxy-substituted alkyl group represented by n-dodecyloxypropyl, etc. preferable.

Examples of the arylcarbamoyl and arylsulfamoyl groups include an unsubstituted arylcarbamoyl group such as phenylcarbamoyl and phenylsulfamoyl, an unsubstituted arylsulfamoyl group, a phenylcarbamoyl group substituted with an alkyl group or a halogen atom, and phenylsulfamoyl group. A substituted phenylcarbamoyl group and a substituted phenylsulfamoyl group represented by groups are preferable.

Moreover, as the alkoxy group of the alkoxycarbonyl group and the alkoxysulfonyl group which may be respectively substituted, an unsubstituted alkoxy group having 1 to 22 carbon atoms represented by methoxy, ethoxy, butoxy and the like is preferable. ), A heterocyclic group (for example, 4-pyridyl, 2-benzimidazolyl and the like), a cyano group, a carboxyl group, an acyl group, a carbamoyl group, an alkoxycarbonyl group, an aryloxycarbonyl group and the like.

The organic group bonded to the mother nucleus by a nitrogen atom, an acylamino group (for example, acetamide, benzamide, 2,
4-di-t-amylphenoxyacetamide, 2,4-dichlorobenzamide and the like), alkoxycarbonylamino group (for example, methoxycarbonylamino, propoxycarbonylamino, t-butoxycarbonylamino and the like), aryloxycarbonylamino group (for example, Phenoxycarbonylamino), sulfonamide group (for example, methanesulfonamide, octanesulfonamide, benzenesulfonamide, 4-dodecyloxybenzenesulfonamide, etc.), anilino group (for example, phenylamino, 2
-Chloroanilino, 2-chloro-4-tetradecanamidoanilino, etc.), ureido group (for example, N-methylureido, N-butylureido, N-phenylureido, N,
N-dibutylureido, etc.), sulfamoylamino group (eg, N, N-disulfamoylamino, N-phenylsulfamoylamino, etc.), amino group (eg, unsubstituted amino, N-methylamino, N, N-diethylamino, etc.), a heterocyclic group (eg, 3,5-dimethyl-1-pyrazolyl, 2,6-dimethylmorpholino group) and the like.

Examples of the organic group bonded to the mother nucleus by an oxygen atom include alkoxy groups (eg, methoxy, ethoxy, i-propoxy, butoxy, 2,2,2-trifluoroethoxy, 3,3,3-
Trifluoropropoxy, 2-chloroethoxy, 2-cyanoethoxy, 2-butanesulfonylethoxy, etc.), aryloxy group (for example, phenoxy, 4-methoxyphenoxy, 2,4-dichlorophenoxy, 4- (2-ethylhexanamide) ) Phenoxy etc.), silyloxy group (eg trimethylsilyloxy, dimethylylphenylylyloxy, dimethyl-t-butylsilyloxy etc.), heterocyclic oxy group (eg tetrahydropyranyloxy, 3-pyridyloxy, 2- ( 1,3-benzimidazolyl) oxy etc.) and the like.

Examples of the organic group bonded to the mother nucleus by a sulfur atom include an alkylthio group (for example, methylthio, ethylthio, butylthio, 3- (4-aminophenyl) propylthio, hexadecylthio, benzilthio, 4-aminobenzylthio, 3- [4- ( 4-dodecyloxybenzene) sulfonamidophenyl] propylthio, 4- (2-butoxy-5-t-octylphenylsulfonamido) benzylthio etc.), arylthio etc. (eg phenylthio, 2
-Naphthylthio, 2,5-dichlorophenylthio, 4-dodecylphenylthio, 2-butoxy-5-t-octylphenylthio, etc., heterocyclic thio group (for example, 2-pyridylthio, 2- (1,3-bunzo) Oxazolyl) thio group, 1
-Hexadecyl-1,2,3,4-tetrazolyl-5-thio group, 1- (3-N-octadecylcarbamoyl) phenyl-1,2,3,4-tetrazolyl-5-thio, etc.) and the like.

The imidazole dye represented by the general formula [1] used as an optical recording medium used in the present invention has a thickness of 600 nm.
It has absorption in the wavelength band of up to 800 nm and has a molar extinction coefficient of 10 ⁴ to 10 ⁵ .

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

Imidazole dye The imidazole dye represented by the general formula [I] includes a compound represented by the following general formula [II] and a general formula [II]
It can be synthesized by reacting the paraphenylene compound represented by I] in the presence of an oxidizing agent.

General formula (II) (In the formula, A and B have the same meanings as described in the above general formula [I].) General formula [III] (In the formula, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are each represented by the general formula [I]
Is synonymous with that described in. ) This reaction, that is, the coupling reaction is preferably carried out under basic conditions, and the reaction medium is an organic solvent,
Either an aqueous organic solvent or an aqueous solution may be used. Also,
The oxidizing agent may be organic or inorganic as long as it has a potential capable of oxidizing p-phenylenediamine. Examples of the oxidizing agent include silver hologenide, hydrogen peroxide, manganese dioxide, potassium persulfate, oxygen and the like. Inorganic oxidizer, also NB
Various organic oxidizing agents such as S and chloramine T can be used.

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

The 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 (0.02 mol) was suspended in 100 ml of acetonitrile, and 4-
Add 4.84 g (0.04 mol) of amidino-pyridine, and add 3 at room temperature.
Stirred for hours. The solvent was distilled off, 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 ml of ethyl acetate, add 300 ml of 10% potassium carbonate solution, and stir at room temperature while stirring 4-amino-3-methyl-N-ethyl-N- ( 10 g of β-methanesulfonamidoethyl) aniline sulfate was added. Then 10
70 ml of a% red blood salt aqueous solution was added dropwise over 2 hours. 2 after completion of dropping
The reaction was carried out at room temperature for an hour. The aqueous layer was discarded, the solution was washed twice more with water, and then the solvent was distilled off. Purification with a silica gel column (developing solvent ethyl acetate: hexane = 1: 3) gave an amorphous solid. Yield 4 g (75%) The structure was confirmed by NMR and FD-Mass.

The imidazole dye used in the present invention is not only extremely useful as a pigment for optical recording, but also used for other purposes, for example, a filter dye for a solid-state photography tube or a color liquid crystal television (for example, mixed with a yellow or magenta dye). To be used as a yellow or blue filter).

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

The substrate in the anti-invention may be either transparent or opaque to the laser light used. Examples of the material of the substrate material include a support of a general recording material such as glass, plastic, paper, a plate-like or foil-like metal, and plastic is suitable from various points. 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 an imidazole dye is used as the information recording layer in the optical recording material of the present invention, the film thickness is 100Å to 5μ.
m, preferably 1000 ° to 3 μm. As a film forming method, a vacuum deposition method, a sputtering method, a doctor blade method,
The film can be formed by a generally used thin film forming method such as a casting method, a spinner method, and a dipping method. Further, a binder can be used if necessary. Known binders such as PVA, PVP, nitrocellulose, cellulose acetate, polyvinyl butyral, and polycarbonate are used, and the amount of the imidazole dye to the resin is preferably 0.01 or more by weight. In the case of film formation by the spinner method, the rotation speed is preferably 500 to 5000 rpm,
After spin coating, treatment such as heating or applying to solvent vapor may be performed depending on the case. Further, in order to improve the stability and light resistance of the recording material, a transition metal chelate compound (for example, acetylacetonate chelate, bisphenyldithiol, salicylaldehyde oxime, bisdithio-α-diketone, etc. is contained as a singlet oxygen quencher. Further, other dyes can be used in combination as required. Other dyes may be other types of imidazole dyes, triarylmethane dyes, azo dyes, cyanine dyes, Other types of dyes such as squarylium dyes may be used.

Doctor blade method, casting method, spinner method, dipping method, in particular, as a coating solvent when forming a recording layer by a coating method such as spinner method, tetrachloroethane, bromoform, dibromoethane, ethyl cellosolve, xylene, chlorobenzene, cyclohexanone Boiling point of 120
Those having a temperature of up to 160 ° C are preferably used.

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

Recording on the optical recording material obtained as described above,
It is carried out by irradiating the recording layer provided on both sides or one side of the substrate with a laser beam converged to about 1 μm, preferably a semiconductor laser beam. In the portion irradiated with the laser light, thermal deformation of the recording layer such as decomposition, evaporation, dissolution and sublimation occurs due to absorption of laser energy.

Reproduction of recorded information is performed by reading the difference in reflectance between a portion where thermal deformation has occurred and a portion where thermal deformation has not occurred using a laser beam.

Laser light used for the optical recording material of the present invention is _{N 2, He-Cd, Ar} , He-Ne, ruby, semiconductor, but such a dye laser and the like, in particular, light weight, ease of handling, compactness A semiconductor laser is preferable from the viewpoint of properties and the like.

Examples Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 1 g of the imidazole dye (5) used in the present invention and synthesized as described above was dissolved in 50 g of dibromoethane, and then 0.2
A dye solution was obtained by filtration using a 2μ filter.

As an optical disk substrate, a PMMA resin substrate (5 inches) with a depth of 700 Å and a width of 0.7μ made of infrared curing resin was used, and 2 ml of the dye solution was dropped on the substrate by a spinner method and rotated at 1200 rpm. Applied in number. After the application, it was dried at 60 ° C. for 10 minutes. In order to measure this film thickness, a film thickness was measured by α-step using a glass plate under the same conditions, and the film thickness was 700Å. The maximum absorption wavelength of this coating film was 640 nm.

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

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

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

When writing was performed on the thus obtained optical disk as a light source using a He-Ne laser having a beam diameter of 2.4 μm and a wavelength of 632.8 nm, pits (holes) having a uniform and clear shape were obtained. The C / N ratio was also good, and the storage stability was also good. The effect of the present invention was also obtained when a semiconductor laser was used as the light source instead of the He-Ne laser.

EFFECT OF THE INVENTION The imidazole dye used in the present invention has high solubility in an organic solvent, so coating by coating can be performed, and an optical recording material obtained by using the dye is
It is extremely useful because it has high reflectance, good contrast, and excellent storage stability.

[Brief description of the drawings]

FIG. 1 shows an absorption spectrum of dye (22) which is an imidazole dye used in the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-63-113077 (JP, A) JP-A-1-110565 (JP, A) JP-A-2-668 (JP, A) JP-A-2- 53866 (JP, A) JP-A-2-53865 (JP, A)

Claims (2)

(57) [Claims] 1. An optical recording material comprising an imidazole dye represented by the general formula [I]. General formula [I] [In the formula, R ₁ and R ₂ each represent a hydrogen atom, an alkyl group or a substituted alkyl group, and R ₁ and R ₂ are bonded to each other to form 5
You may form a membered ring or a 6-membered ring. R ₃ , R ₄ , R ₅ and R ₆ are each a hydrogen atom, a halogen atom,
It represents 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 by a carbon atom, a nitrogen atom, an oxygen atom or a sulfur atom. ] 2. An optical recording material comprising a recording layer and a substrate for recording by changing the state with a laser beam, wherein the recording layer contains an imidazole dye represented by the general formula [I]. The optical recording material according to claim 1, wherein: