JP3771562B2 - Optical recording medium - Google Patents

Description

  The present invention relates to an optical recording medium having a dye film as a recording layer, and more particularly to a write-once type optical recording using a light-stabilized cyanine dye capable of using a solvent having a high evaporation rate in a dye coating process in the manufacturing process. The present invention relates to a medium, particularly an optical disc.

  In recent years, various optical recording disks such as a write once type and a rewritable type have been used in large quantities as a large capacity information carrying medium. Among such optical recording disks, there is one that uses a dye film containing a dye as a main component as a recording layer. Further, structurally, a so-called air sandwich structure in which an air layer is conventionally provided on a dye film, and a recording medium made of a dye film on a recording layer made of a dye film can be reproduced in accordance with the compact disc (CD) standard. (CD-R) has been proposed (see Non-Patent Documents 1 and 2, for example) designed so as to increase the reflectivity by providing a reflective layer such as a close contact. The demand for this CD-R has increased especially in recent years, and the productivity of how many products can be supplied in a short time has become an important issue due to the rapid increase in usage that production cannot keep up with demand. ing.

  In addition, the demand for higher-density recording has increased, and it has become necessary to shorten the wavelength of recording lasers, and DVDs (digital video discs) compatible with lasers with a wavelength of about 635 nm, which are being standardized as the next generation recording media. ) Is about to be commercialized. Development of a DVD-R using a dye for one-time recording is also in progress. In this case, the dye used is also for short wavelengths.

  The recording layer in the above is usually formed by coating using a dye coating solution.

  When such a recording layer is made to correspond to CD-R or DVD-R, if the dye used is a cyanine dye, the wavelength can be easily changed, and a large refractive index can be obtained. It has advantages and is preferred. On the other hand, this cyanine dye has a drawback that it lacks stability to light. Moreover, although the phthalocyanine dye has excellent stability to light, it cannot be used for DVD-R because the wavelength cannot be shortened.

  As stabilization of the cyanine dye, the present inventors have made the salt-forming dye (ion conjugate) of a benzenedithiol metal complex anion, which is a singlet oxygen quencher, and a cyanine dye cation much more stable to light, and light resistance is improved. It has been found that it has been improved and the reproduction deterioration has been reduced, and has been put into practical use (for example, see Patent Document 1).

  However, cyclohexanone, a suitable solvent for dissolving salt-forming dyes, cannot be used to attack the polycarbonate substrate. Therefore, it has been necessary to use a solvent having a considerably low drying rate such as diacetone alcohol. As described above, since the drying speed of the solvent is slow, a long coating time is required for each optical disk, which hinders improvement in productivity. The cyanine dye itself dissolves in a considerable concentration, for example, in TFP (2,2,3,3-tetrafluoropropanol), but salt-forming dyes often lose their solubility. Further, it is often impossible to obtain a concentration sufficient to obtain a required film thickness even when dissolved.

In addition, the ion conjugates of cyanine dyes using conventional quencher anions have an effect on short-wavelength trimethine and monomethine cyanine dyes compared to the effects on conventional long-wavelength heptamethine cyanine and pentamethine cyanine dyes. There was a problem of being inferior.
Japanese Patent No. 1551668 Nikkei Electronics, January 23, 1989, No. 465, P107 Kinki Chemical Association Functional Pigment Subcommittee, March 3, 1989, Osaka Science and Technology Center, PROCEEDINGS SPIE-THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING VOL.1078 PP80-87, "OPTICAL DATA STORAGE TOPICAL MEETING" 17-19, JANUARY 1989 LOS ANGELES

  The object of the present invention is to improve productivity by using a cyanine dye that is highly soluble in a solvent having a high evaporation rate and stable to light, particularly a light-absorbing dye for optical discs such as those for CD-R and DVD-R. And an optical recording medium, particularly a CD-R or DVD-R optical disc, which is excellent in light resistance.

  Such an object is achieved by the present inventions (1) to (4) below.

(1) a substituted benzenedithiol metal complex anion of the following formula (1) as a counter ion, have a recording layer containing a cyanine dye and form a substituted benzenedithiol metal complex anion and the ionic compound, its The recording layer is an optical recording medium formed by applying a solution using a solvent having a vapor pressure at 25 ° C. of 5.3 Torr or more .

(2) The optical recording medium according to (1), wherein the solvent is 2,2,3,3-tetrafluoropropanol .

(3) a cyanine dye having a substrate and contained in a recording layer provided on the substrate is a cyanine dye kaolin represented by the following formula (3) and a substituted benzenedithiol metal complex represented by the formula (1) The optical recording medium according to the above (1) or (2), which is a dye comprising a salt with an anion.

[Where Q ₁ And Q ₂ Represents an atomic group for forming a 5-membered nitrogen-containing heterocycle, each optionally having a condensed ring. R ₂₁ And R ₂₂ Each represents an alkyl group. L represents a methine chain for completing a cyanine dye. ]

  (4) The optical recording medium according to any one of claims 1 to 3 (the above (1) to (3)), wherein the recording layer further contains one or more other dyes.

  According to the present invention, the optical recording medium has a light-stabilized cyanine dye that is an ionic conjugate of the substituted benzenedithiol metal complex anion represented by the above formula (1) and the cyanine dye cation in the recording layer.

  Also provided is a light-stabilized cyanine dye that is a counter ion conjugate of a substituted benzenedithiol metal complex anion represented by the following formula (1) and a cyanine dye cation represented by the following formula (2).

Benzenedithiol metal complexes are known as singlet oxygen quenchers. Then, —SO ₂ R (wherein R is the same as R ₀₁ and R _{02 in} the formula (1)) is bonded to a predetermined position of the benzene ring of the ligand benzenedithiol. The light resistance of the cyanine dye is greatly improved, and its fading is prevented. Moreover, due to the effect of the substituent of sulfamoyl group, nitrogen-containing heterocyclic sulfonyl group, or benzenesulfonyl group, the solubility in a solvent having a high evaporation rate such as TFP (2,2,3,3-tetrafluoropropanol) is very high. The coating time such as spin coating is halved and productivity is improved. In addition, since the dye portion that plays an important role in terms of optical constants is a cyanine dye, the degree of freedom in design is extremely high, and there are almost no restrictions on the wavelength band that can be handled like a phthalocyanine dye. A cyanine dye having a substituted benzenedithiol metal complex anion represented by the above formula (1) as a counter ion and a cyanine dye cation represented by the formula (2) is a novel compound.

  It should be noted that one of the present inventors has filed JP-A-60-118748 (Patent No. 1551667), JP-A-60-118749 (Patent No. 1551668), and JP-A-60-203488 (Patent No. 1717195). ) And the like disclose salt-forming dyes and optical recording media, and it is described that a remarkable improvement in light resistance can be obtained by using such salt-forming dyes. However, these dyes are insufficient in terms of coating time depending on the evaporation rate of the solvent, and are insufficient in terms of durability in a short wavelength region and regeneration deterioration.

  Japanese Patent Application No. 8-219408 and Japanese Patent Application No. 8-219409 describe a method for producing the substituted benzenedithiol metal complex and describe the improvement of light resistance of cyanine dyes. Yes. However, there is no description about salt formation with a cyanine dye using this benzenedithiol metal complex. Also, this benzenedithiol metal complex has a melting point near room temperature depending on the substituent, and there is a problem in stability such as pit deformation expected in a mixed recording layer containing this complex and a cyanine dye. is there.

  According to the present invention, an optical recording medium having excellent light resistance and recording / reproducing characteristics can be obtained.

Hereinafter, embodiments of the present invention will be described in detail.
The light-stabilized cyanine dye of the present invention has a substituted benzenedithiol metal complex anion represented by the following formula (1) as a counter ion and a cyanine dye cation represented by the formula (2). Formula (2) will be described later because it is the same as the preferred cyanine dye cation constituting the light-stabilized cyanine dye used in the optical recording medium of the present invention.

Here, examples of R ₀₁ and R ₀₂ include a dialkylamino group, and the alkyl group (R ₁₁ , R ₁₂ ) bonded to the dialkylamino group is a linear or branched substituent having 1 to 4 carbon atoms in total. An alkyl group which may have a group, specifically, an unsubstituted group such as a methyl group, an ethyl group, a propyl group and a butyl group is preferable. R ₁₁ and R ₁₂ may be a phenyl group, and a halogen atom or an alkyl group having 1 to 4 carbon atoms may be bonded to the phenyl group. In addition to these dialkylamino groups, R ₀₁ and R ₀₂ are 4- to 7-membered, particularly 6-membered (m = 5) imino rings, or cyclic imino groups derived from morpholino rings, or morpholino groups as described above. May be. Furthermore, R ₀₁ and R ₀₂ may be a phenyl group. The phenyl group may be unsubstituted or preferably substituted with an alkyl group having 1 to 4 carbon atoms or a halogen atom.

  In Formula (1), M is a transition metal element, but the transition metal element is not particularly limited, and examples thereof include Fe, Co, Ni, Cu, and Pt. Of these, Cu, Fe, Co, and Ni are preferable, and Cu is most preferable.

In addition, Q1-Q20 of following Table 1 is mentioned as a preferable specific example of the substituted benzenedithiol metal complex anion represented by the said Formula (1). Here, a combination of R ₀₁ , R ₀₂ and M in the formula (1) is shown.

  Next, a method for producing a substituted benzenedithiol metal complex anion represented by the above formula (1) will be described. This metal complex anion is obtained as an ionic conjugate with a quaternary ammonium salt. A complex having a substituted benzenedithiol metal complex anion represented by the formula (1) can be synthesized through 1,2-dibromobenzene as a starting material and an intermediate synthesized therefrom. The manufacturing method will be specifically described below for each process.

(Process 1)
In this step, 1,2-dibromobenzene is reacted with fuming sulfuric acid in a solvent to synthesize 3,4-dibromobenzenesulfonic acid.

The amount of fuming sulfuric acid used here is preferably set to 1.0 to 2.0 times mol, and 1.1 to 1.5 times mol with respect to 1,2-dibromobenzene, based on SO _3. More preferably. The solvent used in this reaction is preferably a halogenated hydrocarbon solvent such as chloroform, carbon tetrachloride, or 1,2-ethylene dichloride.

  The temperature during the reaction is preferably set in the range of 50 to 100 ° C, particularly 65 to 80 ° C. The reaction time is usually 1 to 4 hours, although optimum conditions vary depending on the reaction temperature.

(Process 2)
The 3,4-dibromobenzenesulfonic acid obtained in Step 1 is reacted with thionyl chloride to synthesize 3,4-dibromobenzenesulfonyl chloride. The amount of thionyl chloride used here is usually 1.0 to 2.5 times mol, preferably 1.5 to 2.2 times mol of 3,4-dibromobenzenesulfonic acid.

  In this reaction, as in Step 1, a halogenated hydrocarbon solvent such as chloroform, carbon tetrachloride, 1,2-ethylene dichloride, and an aromatic hydrocarbon solvent such as benzene are preferably used. Here, the use of the same solvent as in Step 1 is advantageous in terms of work efficiency, yield, and the like since it can be carried out continuously with Step 2. Moreover, it is preferable to set reaction temperature to 50-100 degreeC, and it is more preferable to set to 65-80 degreeC. The reaction time is usually 1 to 4 hours, although optimum conditions vary depending on the reaction temperature.

(Process 3)
The 3,4-dibromobenzenesulfonyl chloride obtained in Step 2 is added to the amine or cyclic imine represented by the following formulas (a) and (b), the morpholine represented by (c), or the benzene represented by (d) ( R ₅ represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms) to synthesize 4-substituted sulfonyl-1,2-dibromobenzene (substituted dibromobenzene compound). Note that R ₁₁ , R ₁₂ in formula (a), and m in (b) have the same meaning as in formula (1) above.

  Here, when producing a 4-N, N-dialkylsulfamoyl-1,2-benzenedithiol metal complex, a dialkylamine of the formula (a) is used. In the case of producing 4-piperidylsulfonyl-1,2-benzenedithiol metal complex, piperidine in which m is 5 is used as the compound of the formula (b). Furthermore, when producing a 4-morpholinosulfonyl-1,2-benzenedithiol metal complex, morpholine represented by the formula (c) is used. The amount of the compound represented by the formula (a), (b) or (c) used in this reaction is 1.5 with respect to 3,4-dibromobenzenesulfonic acid used in the normal step (2). It is -4.0 times mole, Preferably it is 2.0-3.0 times mole. In the case of producing a 4-phenylsulfonyl-1,2benzenedithiol metal complex, benzene is used as the compound of the above formula (d). The amount of the compound represented by the formula (d) used in this reaction is 1.0 mol or more with respect to 3,4-dibromobenzenesulfonyl chloride obtained in the normal step (2). In this case, considering the case, it is preferably set to 8.0 to 15.0 times mol.

  In this reaction, as in the case of Step 2, a halogenated hydrocarbon solvent such as chloroform, carbon tetrachloride, 1,2-ethylene dichloride is preferably used.

  Here, the use of the same solvent as in step 2 is advantageous in terms of work efficiency and yield because it can be carried out continuously with step 3. Moreover, it is preferable to set reaction temperature to 15-40 degreeC, and it is more preferable to set to 20-30 degreeC. The reaction time is usually 1 to 3 hours, although optimum conditions vary depending on the reaction temperature.

The 4-substituted sulfonyl-1,2-dibromobenzene obtained in this step is represented by the following formula (4). Here, R ₀ in the formula (4) is synonymous with R ₀₁ and R _{02 in} the formula (1).

(Process 4)
The bromo group of 4-substituted sulfonyl-1,2-dibromobenzene obtained in step 3 is substituted with a mercapto group to synthesize 4-substituted sulfonyl-1,2-benzenedithiol represented by the following formula (5). . Here, R ₀ in the formula (5) has the same _{meaning as in the} case of R ₀₁ and R _{02 in} the formula (1).

  In this step, for example, according to the method described in JP-A-6-25151 and JP-A-5-117225, substitution of a bromo group and a mercapto group can be performed. Specifically, when 4-substituted sulfonyl-1,2-dibromobenzene obtained in Step 3 is reacted with sodium hydrosulfide using iron powder and sulfur powder as a catalyst, the bromine group is replaced with a mercapto group. The desired 4-substituted sulfonyl-1,2-benzenedithiol can be obtained.

  The amount of sodium hydrosulfide used here is usually 1.5 to 4.0 times mol, preferably 1.8 to 2.5 times mol, of 4-substituted sulfonyl-1,2-dibromobenzene. is there. Moreover, the usage-amount of the iron powder used as a catalyst is 0.4-2.0 times mole normally with respect to 4-substituted sulfonyl-1, 2- dibromobenzene, Preferably it is 0.5-1.0 times mole. . The usage-amount of the sulfur powder used as a catalyst is 1.0-20.0 weight% normally with respect to 4-substituted sulfonyl-1, 2- dibromobenzene, Preferably it is 1.0-5.0 weight%.

  The temperature during the reaction in this step is preferably set in the range of 60 to 140 ° C, particularly 70 to 120 ° C.

(Process 5)
The 4-substituted sulfonyl-1,2-benzenedithiol obtained in Step 4 is reacted with a transition metal salt and a quaternary ammonium salt in a lower alcohol to obtain a substituted benzenedithiol metal complex.

  Examples of the lower alcohol used here include methanol, ethanol, isopropanol, tert-butanol and the like. Among these, it is preferable to use methanol from the economical viewpoint.

  As the transition metal salt, a salt of the transition metal (M) contained in the formula (1) of the target substituted benzenedithiol metal complex anion is used, and specific examples of such a salt include copper chloride. Transition metal halogens such as (II), cobalt chloride, nickel (II) chloride, iron (III) chloride, hexachloroplatinum (IV) acid, copper (II) bromide, cobalt bromide, cobalt iodide, and nickel iodide And nitrates such as chloride, copper nitrate and cobalt nitrate, sulfates such as copper sulfate and cobalt sulfate, and acetates such as copper acetate and cobalt acetate. In addition, the thing preferable as a salt of a transition metal is a halide, especially a chloride from the point of economical efficiency and reactivity.

  The amount of the transition metal salt used is preferably set to 0.3 to 10 moles relative to 4-substituted sulfonyl-1,2-benzenedithiol. When the amount is less than 0.3 times mol, the yield is low. Conversely, even if the amount exceeds 10 times mol, the yield is not improved and it is uneconomical.

  As quaternary ammonium salts, tetra-n-butylammonium bromide, tetra-n-butylammonium chloride, tetraethylammonium bromide, tetraethylammonium chloride, tetraphenylammonium bromide, tetraphenylammonium chloride, tetrabenzylammonium bromide, tetrabenzylammonium Chloride, trimethylbenzylammonium bromide, trimethylbenzylammonium chloride and the like. Among them, in terms of economy, reactivity, tetra-n-butylammonium bromide, tetra-n-butylammonium chloride, tetraethylammonium bromide, tetraethylammonium chloride Is preferred.

  The amount of the quaternary ammonium salt used is set to 0.3 to 1.0 times mol, particularly 0.4 to 0.9 times mol, with respect to 4-substituted sulfonyl-1,2-benzenedithiol. It is preferable to do. When the amount is less than 0.3 times mol, the yield is low. On the other hand, even if the amount exceeds 1.0 times mol, the yield is not improved and it is uneconomical.

  The reaction in this step is preferably performed in the presence of an alkoxide because the yield can be increased. Examples of the alkoxide that can be used here include sodium methylate, sodium ethylate, potassium tert-butylate, and the like, and sodium methylate is preferably used from the viewpoint of economy.

  The amount used in the case of using such an alkoxide may be set to 1.5 to 10 times mol, particularly 2.0 to 3.0 times mol, with respect to 4-substituted sulfonyl-1,2-benzenedithiol. preferable. When the amount is less than 1.5 times mol, the yield is low, and conversely, even if the amount exceeds 10 times mol, the yield is not improved and it is uneconomical.

  The temperature during the reaction in this step is preferably set in the range of 15 to 100 ° C, particularly 20 to 95 ° C. The reaction time is usually 1 to 3 hours, although optimum conditions vary depending on the reaction temperature.

  The optical recording medium of the present invention is a photostabilization which is a salt of a substituted benzenedithiol metal complex anion of the above formula (1) as a dye and a cyanine dye cation of the following formula (3) as a dye. Contains cyanine dye.

In the formula, Q ₁ and Q ₂ may be the same or different from each other, and each represents an atomic group for generating a 5-membered nitrogen-containing heterocycle which may have a condensed ring. Examples of such heterocycle include indolenine ring, 4,5-benzoindolenin ring, 5,6-benzoindolenin ring, thiazole ring, benzothiazole ring, oxazole ring, benzoxazole ring, pyridine ring, quinoline ring, Examples include an imidazole ring, a benzimidazole ring, a selenazole ring, a benzoselenazole ring, and a pyrimidine ring. These rings may be substituted with a halogen group, an alkyl group, an alkoxy group, an alkylaminosulfamide group, an alkylamino group or an aryl group.

  As an alkyl group, a C1-C5 thing is preferable, may be linear or may have a branch and may have a cycloalkyl group depending on the case. Further, it may have a substituent, and as such a substituent, a halogen group (fluoro group, chloro group, etc.) and the like are preferable. As the alkyl group, an alkyl group which may have a linear or branched substituent having 1 to 4 carbon atoms is particularly preferable, and specifically, a methyl group, an ethyl group, an n-propyl group, an isopropyl group. , N-butyl group, isobutyl group, s-butyl group, t-butyl group, trifluoromethyl group and the like.

  As the alkoxy group, those having 1 to 4 carbon atoms in the alkyl moiety are preferable, and may be substituted with a halogen group (fluoro group or the like). Specific examples of such an alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a tetrafluoropropoxy group.

  As the alkylaminosulfamide group, those having 1 to 4 carbon atoms in the alkyl moiety are preferable, and a methylaminosulfamide group, an ethylaminosulfamide group, a propylaminosulfamide group, a butylaminosulfamide group. Etc.

  The alkylamino group preferably has 1 to 4 carbon atoms in the alkyl portion, and may be a monoalkylamino group or a dialkylamino group, and examples thereof include a methylamino group, a dimethylamino group, a diethylamino group, and a dibutylamino group.

The aryl group may be a single ring or a condensed ring, and may further have a substituent. The total number of carbon atoms is preferably 6-20. Specifically, a phenyl group, a naphthyl group, etc. are mentioned, A phenyl group etc. are preferable. These may further have a substituent, and examples of such a substituent include an alkyl group, an aryl group, an alkoxy group, a halogen atom, an amino group, and a sulfamoyl group. To 5 alkyl groups (for example, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, iso- Pentyl group, neo-pentyl group, tert-pentyl group, 1-methylbutyl group), alkoxy group (for example, methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group) Group), aryl group (eg phenyl group, tolyl group, biphenyl group, naphthyl group), halogen group (eg F Cl, Br, I, preferably F, Br)
Etc. are preferred.

R ₂₁ and R ₂₂ may be different be the same as each other, each represents an alkyl group. These carbon atoms are preferably 1 to 8, and may be branched. These may be substituted with a hydroxy group, a halogen group (for example, F, Cl, Br, I, etc.), an alkoxy group (for example, a methoxy group, an ethoxy group, a propoxy group, etc.) and the like. L represents a methine chain for completing a cyanine dye. In this case, — (CH═CH) n—CH═ is preferable, and n is preferably 0 to 3, particularly preferably 1 to 2.

  Among these, more preferred cyanine dyes are those of the indolenine type represented by the following formula (2). That is, it is the same as the cation constituting the light-stabilized cyanine dye of the present invention.

In the formula, Z ₁ and Z ₂ may be the same or different and each represents a condensed benzene ring or a condensed naphthalene ring, and the ring completed by Z ₁ and Z ₂ is an indolenine ring, 4 , 5-benzoindolenin ring (including 6,7-benzoindolenin ring) or 5,6-benzoindolenin ring. These rings may be bonded to the above substituents. R ₂₁ and R ₂₂ are as defined above, and n is 1 or 2.

  Specific examples of preferred cyanine dye cations of formula (2) are shown below. Here, some are shown in accordance with the display of the formula (D-1) to the formula (D-8).

Such a cyanine dye cation usually exists as a cyanine dye having ClO ₄ ⁻ , BF ₄ ⁻ , I ⁻ or the like as a counter ion. The light-stabilizing dye of the present invention is obtained using such a cyanine dye or the like and a quaternary ammonium salt of the metal complex anion represented by the above formula (1).

  Specifically, first, a cyanine dye and a metal complex (quaternary ammonium salt) dissolved in an organic solvent, preferably dichloroethane, dichloromethane or the like are used. Distilled water for washing is added thereto, and mixing and separation are preferably performed three times or more, followed by washing to remove unnecessary ion components. Thereafter, a dehydrating agent, preferably anhydrous calcium chloride, is added for dehydration, the dehydrating agent is filtered off, concentrated, and an alcohol solvent such as methanol is added to precipitate and crystallize the light stabilizing dye of the present invention. .

  These dyes can be identified by elemental analysis, visible absorption spectrum, infrared absorption spectrum, mass spectrum, nuclear magnetic resonance absorption spectrum and the like. These dyes have a λmax (measured with an 80 nm thick dye thin film) of about 500 to 750 nm and a melting point (mp) of about 80 to 280 ° C.

  Table 2 below shows specific examples of the light stabilizing dye used in the present invention. Here, a combination of a cyanine dye cation and a substituted benzenedithiol metal complex anion is shown, and specific examples include the light stabilizing dye of the present invention.

  The recording layer using the light stabilizing dye is preferably used for a write-once optical recording disk (DVD-R, CD-R, CD-RII). 23-27 can be preferably used for CD-R. Further, only one light stabilizing dye may be used, or two or more light stabilizing dyes may be used in combination. Such a recording layer is preferably formed by a spin coating method, a screen printing method, a spray coating method or the like using a coating solution containing the above-described dye. In particular, it is preferable to use a spin coating method in which a coating solution is spread and applied on a rotating substrate.

  As the coating solvent at this time, specifically, an alcohol type such as diacetone alcohol, ethylene glycol monoethyl ether, TFP (2,2,3,3-tetrafluoropropanol) is preferable, and TFP having a particularly high evaporation rate, A vapor pressure of 25 ° C. such as ethylene glycol monoethyl ether is preferably 5.3 Torr or higher, particularly 5.3 to 110 Torr alcohol. The solubility of the light-stabilized cyanine dye of the present invention in these solvents is extremely high. These solvents may be used alone or in combination of two or more.

  After the spin coating as described above, the coating film is dried as necessary. The thickness of the recording layer thus formed is appropriately set according to the target reflectance and the like, but the thickness is usually 50 to 300 nm on average, particularly about 80 to 300 nm. Is preferred.

  In the optical recording medium of the present invention, the recording layer may further contain one or more other dyes, a stabilizer such as a quencher, or a binder in addition to the light-stabilized cyanine dye. Further, a recording layer in which the light stabilizing dye layer and another dye layer are laminated may be used.

Among these other dyes, cyanine dyes having a counter anion different from that of the present invention are preferable, and the skeleton types such as thiazole series, oxazole series, imidazole series, quinoline series, pyrimidine series, indolenine series, and benzoindolenine series are preferred. Regardless, it can be used and may be an asymmetric structure having two types of rings. There are no particular restrictions on the N-substituent and ring substituent. In addition, the linking group may be an unsubstituted or substituted monomethine, dimethine chain, trimethine chain, pentamethine chain, heptamethine chain, or a methine chain having a structure in which a 5-membered ring, a 6-membered ring or two or more rings are condensed. Good. Of these, indolenine dyes having a counter ion of ClO ₄ ⁻ , BF ₄ ⁻ , I ⁻ or the like are particularly preferable. The addition amount of these other dyes is preferably 60 wt% or less and 50 wt% or less with respect to the whole dye.

  Such indolenine and benzoindolenine cyanine dyes are most suitable from the viewpoints of stability, solubility, and the like. An asymmetric structure may be used in terms of wavelength adjustment and solubility. Further, by adjusting the carbon of the N side chain from 1 to 5, it is possible to finely adjust the wavelength and further improve the solubility. In this case, the solubility can be further improved as a branched alkyl group.

  The pigment content in the coating solution may be selected according to the thickness of the pigment film, etc., preferably 0.5-5 wt%, more preferably 0.8-2.5 wt%. Since the light-stabilized cyanine dye of the present invention has good solubility, the content relative to the coating solution can be easily adjusted. In addition to the stabilizer, the coating solution may appropriately contain a binder, a dispersant and the like.

  The substrate is in the form of a disk, and in order to enable recording and reproduction from the back side of the substrate, recording light and reproduction light (wavelength of about 500 to 900 nm, especially wavelength of about 600 to 800 nm, further wavelength of 630 to 630). It is preferable to use a resin or glass that is substantially transparent (preferably a transmittance of 88% or more) with respect to about 690 nm or about 750 to 800 nm, and has a diameter of about 64 to 200 mm and a thickness. It shall be about 0.6 to 1.2 mm.

  A tracking groove is formed on the recording layer forming surface of the substrate.

  In terms of material, the substrate is preferably a resin, and various thermoplastic resins such as a polycarbonate resin, an acrylic resin, an amorphous polyolefin, and a polystyrene resin are suitable. And it can manufacture in accordance with well-known methods, such as injection molding, using such resin. The groove is preferably formed at the time of molding the substrate. In addition, you may form the resin layer which has a groove | channel by 2P method etc. after board | substrate manufacture. In some cases, a glass substrate may be used.

  On the recording layer, a reflective layer is formed in direct contact. As the reflective layer, a highly reflective metal or alloy such as Au, Ag, Cu, or AgCu may be used, and Au and Ag are particularly preferable. Moreover, what laminated | stacked these metals may be used. The thickness of the reflective layer is preferably 500 A or more, and may be formed by vapor deposition, sputtering, or the like.

  A protective film is provided on the reflective layer. The protective film is usually formed of various resin materials such as ultraviolet curable resin to a thickness of about 0.5 to 100 μm. The protective film may be a layer or a sheet. The protective film may be formed by a usual method such as spin coating, gravure coating, spray coating, dipping or the like.

  The disc structure of the DVD-R is a two-ply type, and a layer having the same structure as described above is formed on a 0.6 mm thick substrate (usually polycarbonate resin), and the protective film is bonded to an adhesive (thermoplastic resin). Or a thermosetting resin).

  The substrate of this material conforms to that of the CD described above, but the groove depth is 0.1 to 0.25 μm, the width is 0.2 to 0.4 μm, and the groove pitch is 0.5 to 1.0 μm.

  The recording layer has a thickness of 500 to 3000 A, and the complex refractive index at 635 nm is n = 2.0 to 2.6, and k = 0.02 to 0.20.

  The optical recording medium of the present invention is not limited to a contact type optical recording disk, and may be any one as long as it has a recording layer containing a dye. Examples of such a recording medium include a pit-forming optical recording disk having an air sandwich structure, and the same effects can be obtained by applying the present invention.

Hereinafter, specific examples of the present invention will be shown together with comparative examples, and the present invention will be described in more detail.
First, a synthesis example of a salt of a substituted benzenethiol metal complex used for the synthesis of the light-stabilized cyanine dye of the present invention is shown.

Synthesis example 1
(Synthesis of ammonium salt of substituted benzenedithiol metal complex Q1)
Prepare a 300 ml four-necked flask equipped with a stirrer, a cooler and a thermometer. To this, add 120 g of 1,2-ethylene dichloride and 76 g (0.32 mol) of 1,2-dibromobenzene, and add nitrogen gas. While slowly passing through, 56 g (0.42 mol) of 60% fuming sulfuric acid was added dropwise and reacted at 70 ° C. for 2 hours. The reaction product solution was cooled and then filtered and dried to obtain 95 g of crude 3,4-dibromobenzenesulfonic acid.

  Next, a 500 ml four-necked flask equipped with a stirrer, a condenser and a thermometer was prepared, and 95 g of crude 3,4-dibromobenzenesulfonic acid obtained, 225 g of 1,2-ethylene dichloride, N, N -28.5 g of dimethylformamide was added, and 73 g (0.61 mol) of thionyl chloride was further added dropwise and reacted at 60 to 65 ° C for 1 hour. The reaction product solution was cooled to room temperature, dropped into 460 g of water, and stirred at 0 to 10 ° C. for 0.5 hour.

The obtained reaction product liquid was separated, 58 g (0.79 mol) of diethylamine was added dropwise to 290 g of the organic layer obtained by removing the aqueous layer, and the mixture was reacted at room temperature for 1 hour. To this was further added 200 g of water, followed by liquid separation to remove the aqueous layer, and then the solvent was distilled off under reduced pressure to obtain 87 g of 4-N, N-diethylsulfamoyl-1,2-dibromobenzene.
The yield was 73%.

  To 10 g of the obtained 4-N, N-diethylsulfamoyl-1,2-dibromobenzene, 50 g of N, N-dimethylformamide, 1.2 g (0.022 mol) of iron powder and 0.4 g (0. 013 mol) was added, and a solution prepared by dissolving 5.0 g (0.062 mol) of 70% sodium hydrosulfide in 50 g of N, N-dimethylformamide was added dropwise and reacted at 95 ° C. for 2 hours.

  To this solution, 30 g of a 10% sodium methylate-methanol solution (0.056 mol as sodium methylate) was added dropwise and stirred for 1 hour, and then 2.3 g (0.014 mol) of cupric chloride dihydrate. ) In 10 g of methanol was further added dropwise and reacted at 72 ° C. for 1 hour. After cooling the reaction solution to room temperature, 14.6 g of a 31% tetrabutylammonium bromide-methanol solution (0.014 mol as tetrabutylammonium bromide) was added dropwise, and the reaction was allowed to stir at room temperature for 2 hours.

  The obtained reaction solution was concentrated and purified by silica gel column chromatography. The fraction was concentrated to obtain 4.8 g of a desired dark green 4-N, N-diethylsulfamoyl-1,2-benzenedithiol copper complex. The yield was 42% based on 4-N, N-diethylsulfamoyl-1,2-dibromobenzene. The structure of the obtained 4-N, N-diethylsulfamoyl-1,2-benzenedithiol copper complex is as follows.

  Table 3 shows analytical values and physical properties of the obtained 4-N, N-diethylsulfamoyl-1,2-benzenedithiol copper complex.

Synthesis example 2
(Synthesis of ammonium salt of substituted benzenedithiol metal complex Q10)
Instead of 2.3 g (0.014 mol) of cupric chloride dihydrate used in Synthesis Example 1, 3.2 g (0.014 mol) of nickel chloride (II) hexahydrate was used. Were the same as in Synthesis Example 1 to obtain 5.2 g of a solid of 4-N, N-diethylsulfamoyl-1,2-benzenedithiol nickel complex. The yield was 45% based on 4-N, N-diethylsulfamoyl-1,2-dibromobenzene. The structure of the obtained 4-N, N-diethylsulfamoyl-1,2-benzenedithiol nickel complex is as follows.

  Table 4 shows analytical values and physical properties of the resulting 4-N, N-diethylsulfamoyl-1,2-benzenedithiol nickel complex.

Synthesis example 3
(Synthesis of ammonium salt of substituted benzenedithiol metal complex Q12)
Prepare a 300 ml four-necked flask equipped with a stirrer, a cooler and a thermometer. To this, add 90 g of 1,2-ethylene chloride and 45 g (0.19 mol) of 1,2-dibromobenzene, and add nitrogen gas. While slowly passing through, 53.5 g (0.20 mol) of 30% fuming sulfuric acid was added dropwise and reacted at 70 ° C. for 2 hours. The reaction product solution was cooled and then filtered and dried to obtain 57 g of crude 3,4-dibromobenzenesulfonic acid.

  Next, a 500 ml four-necked flask equipped with a stirrer, a condenser and a thermometer was prepared, and 57 g of crude 3,4-dibromobenzenesulfonic acid obtained, 155 g of 1,2-ethylene dichloride, N, N -18 g of dimethylformamide was added, and 38 g (0.32 mol) of thionyl chloride was added dropwise to react at 60 to 65 ° C for 1 hour. The reaction product solution was cooled to room temperature, dropped into 300 g of water, and stirred at 0 to 10 ° C. for 0.5 hour.

  The obtained reaction product liquid was separated, and 35.7 g (0.42 mol) of piperidine was added dropwise to 191 g of the organic layer obtained by removing the aqueous layer, and reacted at room temperature for 1 hour. To this was further added 150 g of water, followed by liquid separation to remove the aqueous layer, and then the solvent was distilled off under reduced pressure to obtain 53.5 g of 4-piperidylsulfonyl-1,2-dibromobenzene. The yield was 73%.

  To 10 g (0.26 mol) of 4-piperidylsulfonyl-1,2-dibromobenzene thus obtained, 50 g of N, N-dimethylformamide, 0.8 g (0.014 mol) of iron powder and 0.4 g (0. 013 mol) was added, and a solution prepared by dissolving 4.6 g (0.057 mol) of 70% sodium hydrosulfide in 50 g of N, N-dimethylformamide was added dropwise and reacted at 100 ° C. for 2 hours.

  To this solution, 31.2 g of a 10% sodium methylate-methanol solution (0.057 mol as sodium methylate) was added dropwise and stirred for 1 hour. Then, 3.4 g (0 of nickel (II) chloride hexahydrate) .014 mol) in 10 g of methanol was further added dropwise and reacted at room temperature for 1 hour. Thereafter, 14.6 g of a 32% tetrabutylammonium bromide-methanol solution (0.015 mol as tetrabutylammonium bromide) was added dropwise, and the mixture was reacted at room temperature for 2 hours.

  The obtained reaction solution was concentrated and purified by silica gel column chromatography. The fraction was concentrated to obtain 1.8 g of the target dark green 4-piperidylsulfonyl-1,2-benzenedithiol nickel complex. The yield was 16% based on 4-piperidylsulfonyl-1,2-dibromobenzene. The structure of the obtained 4-piperidylsulfonyl-1,2-benzenedithiol nickel complex is as follows.

  Table 5 shows analytical values and physical properties of the resulting 4-piperidylsulfonyl-1,2-benzenedithiol nickel complex.

Synthesis example 4
(Synthesis of ammonium salt of substituted benzenedithiol metal complex Q3)
Aside from using 2.5 g (0.015 mol) of cupric chloride dihydrate instead of 3.4 g (0.014 mol) of nickel chloride (II) hexahydrate used in Synthesis Example 3. The same operation as in Synthesis Example 3 was performed to obtain 5.1 g of a solid of 4-piperidylsulfonyl-1,2-benzenedithiol copper complex. The yield was 45% based on 4-piperidylsulfonyl-1,2-dibromobenzene. The structure of the obtained 4-piperidylsulfonyl-1,2-benzenedithiol copper complex is as follows.

  Table 6 shows analytical values and physical properties of the obtained 4-piperidylsulfonyl-1,2-benzenedithiol copper complex.

Synthesis example 5
(Synthesis of ammonium salt of substituted benzenedithiol metal complex Q14)
Prepare a 300 ml four-necked flask equipped with a stirrer, a cooler and a thermometer. To this, add 80 g of 1,2-ethylene dichloride and 51 g (0.22 mol) of 1,2-dibromobenzene, and add nitrogen gas. While slowly passing through, 38 g (0.29 mol) of 60% fuming sulfuric acid was added dropwise and reacted at 70 ° C. for 2 hours. The reaction product solution was cooled and then filtered and dried to obtain 51 g of crude 3,4-dibromobenzenesulfonic acid.

  Next, a 500 ml four-necked flask equipped with a stirrer, a condenser and a thermometer was prepared, and 51 g of crude 3,4-dibromobenzenesulfonic acid obtained, 155 g (1.98 mol) of benzene, N, 20 g of N-dimethylformamide was added, and 27 g (0.23 mol) of thionyl chloride was further added dropwise to react at 60 to 65 ° C. for 1 hour. The reaction product solution was cooled to room temperature, dropped into 300 g of water, and stirred at 0 to 10 ° C. for 0.5 hour.

  The obtained reaction product liquid was separated, and 28 g (0.21 mol) of aluminum chloride was added dropwise to 280 g of the organic layer obtained by removing the aqueous layer, and reacted at 75 ° C. for 1 hour. To this was further added 300 g of water, followed by liquid separation to remove the aqueous layer, and then the solvent was distilled off under reduced pressure to obtain 38 g of 4-phenylsulfonyl-1,2-dibromobenzene. The yield was 47%.

  To 5.1 g (0.014 mol) of 4-phenylsulfonyl-1,2-dibromobenzene thus obtained, 35 g of N, N-dimethylformamide, 0.7 g (0.013 mol) of iron powder and 0.3 g of sulfur powder ( 0.0094 mol) was added, and a solution prepared by dissolving 2.5 g (0.031 mol) of 70% sodium hydrosulfide in 25 g of N, N-dimethylformamide was added dropwise and reacted at 95 ° C. for 2 hours.

  To this solution, 15.6 g of an 11% sodium methylate-methanol solution (0.0285 mol as sodium methylate) was added dropwise and stirred for 1 hour, and then 1.7 g (0.0072) of nickel (II) hexahydrate. (Mol) was added dropwise to a solution of 6 g of methanol and reacted at 72 ° C. for 1 hour. After cooling the reaction solution to room temperature, 9.3 g of a 25% tetrabutylammonium bromide-methanol solution (0.0071 mol as tetrabutylammonium bromide) was added dropwise, and the reaction was allowed to stir at room temperature for 2 hours.

  The obtained reaction solution was concentrated and purified by silica gel column chromatography. The fraction was concentrated to obtain 2.8 g of the target dark green 4-phenylsulfonyl-1,2-benzenedithiol nickel complex. The yield was 48% based on 4-phenylsulfonyl-1,2-dibromobenzene. The structure of the obtained 4-phenylsulfonyl-1,2-benzenedithiol nickel complex is as follows.

  Table 7 shows analytical values and physical properties of the resulting 4-phenylsulfonyl-1,2-benzenedithiol nickel complex.

Synthesis Example 6
(Synthesis of ammonium salt of substituted benzenedithiol metal complex Q4)
Instead of 1.7 g (0.0072 mol) of nickel chloride (II) hexahydrate used in Synthesis Example 5, 1.2 g (0.0070 mol) of cupric chloride dihydrate was used. Performed the same operation as in Synthesis Example 1 to obtain 3.3 g of a solid of 4-phenylsulfonyl-1,2-benzenedithiol copper complex. The yield was 57% based on 4-phenylsulfonyl-1,2-dibromobenzene. The structure of the obtained 4-phenylsulfonyl-1,2-benzenedithiol copper complex is as follows.

  Table 8 shows analytical values and physical properties of the resulting 4-phenylsulfonyl-1,2-benzenedithiol copper complex.

Synthesis example 7
(Synthesis of ammonium salt of substituted benzenedithiol metal complex Q9)
Prepare a 300 ml four-necked flask equipped with a stirrer, a cooler and a thermometer. To this, add 90 g of 1,2-ethylene dichloride and 45 g (0.19 mol) of 1,2-dibromobenzene, and add nitrogen gas. While slowly passing through, 53.5 g (0.20 mol) of 30% fuming sulfuric acid was added dropwise and reacted at 70 ° C. for 2 hours. The reaction product solution was cooled and then filtered and dried to obtain 57 g of crude 3,4-dibromobenzenesulfonic acid.

  Next, a 500 ml four-necked flask equipped with a stirrer, a condenser and a thermometer was prepared, and 57 g of crude 3,4-dibromobenzenesulfonic acid obtained, 155 g of 1,2-ethylene dichloride, N, N -18 g of dimethylformamide was added, 38 g (0.32 mol) of thionyl chloride was added dropwise, and the mixture was reacted at 60 to 65 ° C for 1 hour. The reaction product solution was cooled to room temperature, dropped into 300 g of water, and stirred at 0 to 10 ° C. for 0.5 hour.

  The obtained reaction product liquid was separated, 36.6 g (0.42 mol) of morpholine was added dropwise to 191 g of the organic layer obtained by removing the aqueous layer, and reacted at room temperature for 1 hour. Further, 150 g of water was added, and the mixture was separated to remove the aqueous layer. Then, the solvent was distilled off under reduced pressure to obtain 54.9 g of 4-morpholinosulfonyl-1,2-dibromobenzene. The yield was 75%.

10 g of the resulting 4-morpholinosulfonyl-1,2-dibromobenzene (0.
026 mol), 50 g of N, N-dimethylformamide, 0.8 g (0.014 mol) of iron powder and 0.4 g (0.013 mol) of sulfur powder were added, and 4.6 g (0. 057 mol) was dissolved in 50 g of N, N-dimethylformamide and dropped at 100 ° C. for 2 hours.

  To this solution, 31.2 g of a 10% sodium methylate-methanol solution (0.057 mol as sodium methylate) was added dropwise and stirred for 1 hour, and then 2.5 g of cupric chloride dihydrate (0. 015 mol) in 10 g of methanol was further added dropwise and reacted at room temperature for 1 hour. Thereafter, 14.6 g of a 32% tetrabutylammonium bromide-methanol solution (0.015 mol as tetrabutylammonium bromide) was added dropwise, and the mixture was reacted at room temperature for 2 hours.

  The obtained reaction solution was concentrated and purified by silica gel column chromatography. The fraction was concentrated to obtain 4.8 g of a desired dark green 4-morpholinosulfonyl-1,2-benzenedithiol copper complex. The yield was 42% based on 4-morpholinosulfonyl-1,2-dibromobenzene. The structural formula of the obtained 4-morpholinosulfonyl-1,2-benzenedithiol copper complex is as follows.

  Table 9 shows analytical values and physical properties of the obtained 4-morpholinosulfonyl-1,2-benzenedithiol copper complex.

Example 1
(Synthesis of light-stabilized cyanine dyes)
<Exemplary Compound No. Synthesis of 1>
ClO ₄ illustrated above cyanine dye cation D-8-6 ^- salt and respectively tetrabutylammonium salt 0.001mol of Synthesis Example 1 of a metal complex anion Q1 (substituent _{R = -N (C 2 H 5} ) 2) Was dissolved in 20 ml of 1,2-ethylene dichloride. After shaking well with 20 ml of distilled water using a separatory funnel, the aqueous layer was separated and discarded. The 1,2-ethylene dichloride layer was further washed twice with 20 ml of distilled water, and then dehydrated by adding granular anhydrous calcium chloride to the 1,2-ethylene dichloride layer. This was left overnight, then the calcium chloride was filtered off, the filtrate was concentrated with an evaporator, and methanol was added to precipitate and crystallize the desired salt-forming dye (Exemplary Compound No. 1).

<Exemplary Compound No. Synthesis of 2-5, 7, 18, 27, 69, 92, 94, 105-107>
Exemplified Compound No. 1 was synthesized from the corresponding cyanine dye cation salt and metal complex anion salt.

  In addition, other exemplary compounds in Table 2 could be synthesized similarly.

(Comparative dye synthesis)
Exemplified Compound No. 1, the following metal complex salts (Q21 salt, Q22 salt) were used, and the dye cations D-1-1, D-8-6, D-6-1, D-3-4 and the following: In combination, the comparative dye compound No. 201-203 and 205 were synthesized. In addition, Compound No. A ClO ₄ ^- salt of the dye cation D-6-1 was also prepared as 204.

  These cyanine dyes could be identified by the absorption maximum wavelength, molar extinction coefficient, and quantitative analysis of the central metal.

  The light-stabilized dye of the present invention synthesized above has improved solubility in a solvent, and particularly has a very high solubility in TFP or the like having a high evaporation rate. In addition, the melting point of substituted benzenedithiol metal complexes themselves (tetrabutylammonium salt) is generally low, whereas those formed with salts using cyanine dyes have a high melting point in many cases, with some exceptions. It has become. Table 10 below shows the melting point of the metal complex and the compound No. 1 of the present invention after salt formation using a cyanine dye. Melting | fusing point of 1-5, 105, 87 is shown.

Example 2
(Preparation of sample with optical recording layer)
Polycarbonate was injection molded to obtain a substrate having a diameter of 120 mm and a thickness of 1.2 mm. No groove was provided on the recording layer forming surface of the substrate.

<Sample 11>
Light obtained in the same manner as in Example 1 using an ion conjugate (Compound No. 7) of the substituted benzenedithiol metal complex anion Q1 of the present invention and the cyanine dye cation D-1-1 on this resin substrate. Coating was performed by a spin coat method using a 2,2,3,3-tetrafluoropropanol 1.0 wt% solution of a stabilized cyanine dye, and dried to obtain a dye film of 100 nm. The coating time was 20 seconds. This film was irradiated with 80,000 lux xenon lamp (Xe lamp) light on the film surface, but 97% of the dye remained even after 100 hours (dye remaining rate 97%).

The dye residual rate (%) is calculated by measuring the initial transmittance T ₀ (%) before light irradiation and the transmittance T (%) after light irradiation and according to the following formula. The same applies to the following.
Dye remaining rate (%) = (100−T) × 100 / (100−T ₀ )
The results are shown in Table 11.

<Sample 12>
In the same manner as in sample 11, using a substituted benzenedithiol metal complex anion Q1 and a light-stabilized cyanine dye (compound No. 1) of cyanine dye cation D-8-6, coating is performed, and drying is performed to obtain a dye film of 100 nm. Obtained. The coating time was 20 seconds. The film was irradiated with light from an 80,000 lux Xe lamp, but 98% of the dye remained even after 100 hours. The results are shown in Table 11.

<Sample 13>
In the same manner as in Sample 11, using a substituted benzenedithiol metal complex anion Q2 and a light-stabilized cyanine dye (compound No. 2) of cyanine dye cation D-8-6, coating and drying were performed to obtain a dye film of 100 nm. Obtained. The coating time was 20 seconds. The film was irradiated with light from an 80,000 lux Xe lamp, but 98% of the dye remained even after 100 hours. The results are shown in Table 11.

<Sample 14>
In the same manner as in Sample 11, using a substituted benzenedithiol metal complex anion Q3 and a light-stabilized cyanine dye (compound No. 3) of cyanine dye cation D-8-6, coating is performed, and drying is performed to obtain a dye film of 100 nm. Obtained. The coating time was 20 seconds. The film was irradiated with light from an 80,000 lux Xe lamp, but 99% of the dye remained even after 100 hours. The results are shown in Table 11.

<Sample 15>
Coating is performed by spin coating using a substituted benzenedithiol metal complex anion Q1 and a 2.3 wt% ethyl cellosolve solution of a light-stabilized cyanine dye (compound No. 1) of the cyanine dye cation D-8-6, and then dried. Thus, a dye film of 100 nm was obtained. The coating time was 40 seconds. The film was irradiated with light from an 80,000 lux Xe lamp, but 98% of the dye remained even after 100 hours. The results are shown in Table 11.

<Sample 16>
In the same manner as in Sample 15, coating was performed using a substituted benzenedithiol metal complex anion Q2 and a light-stabilized cyanine dye (compound No. 2) of cyanine dye cation D-8-6, and dried to obtain a dye film of 100 nm. Obtained. The coating time was 40 seconds. The film was irradiated with light from an 80,000 lux Xe lamp, but 97% of the dye remained even after 100 hours. The results are shown in Table 11.

<Sample 17>
In the same manner as in Sample 11, using a substituted benzenedithiol metal complex anion Q1 and a light-stabilized cyanine dye (compound No. 18) of cyanine dye cation D-3-4, coating is performed, and drying is performed to obtain a dye film of 100 nm. Obtained. The coating time was 20 seconds. The film was irradiated with light from an 80,000 lux Xe lamp, but 98% of the dye remained even after 100 hours. The results are shown in Table 11.

<Sample 18>
In the same manner as in Sample 11, using a substituted benzenedithiol metal complex anion Q2 and a light-stabilized cyanine dye (compound No. 106) of cyanine dye cation D-3-4, coating is performed, and drying is performed to obtain a dye film of 100 nm. Obtained. The coating time was 20 seconds. The film was irradiated with light from an 80,000 lux Xe lamp, but 97% of the dye remained even after 100 hours. The results are shown in Table 11.

  As is apparent from Table 11, the light-stabilized cyanine dye of the present invention can form an optical recording layer in an extremely short time by using it in an optical disk such as a DVD-R or CD-R, and the production efficiency can be improved. It can be improved significantly. Further, it is expected to show physically stable characteristics and good recording / reproducing characteristics. The above sample No. Nos. 11 to 16 are sample Nos. 17 and 18 are particularly suitable for a CD-R.

Comparative Example 1
(Preparation of sample with optical recording layer)
<Sample 21>
In the same manner as in Example 2, 2,2,3,3-tetrafluoro of a cyanine dye salt (Comparative Compound No. 201) of the metal complex anion Q21 and cyanine dye cation D-1-1 on the substrate. When a propanol (TFP) solution was used and coating was attempted by a spin coating method, the salt-forming dye was hardly dissolved in TFP and could not be coated. The results are shown in Table 12.

<Sample 22>
Similar to sample 21, 2,2,3,3-tetrafluoropropanol (TFP) of the cyanine dye salt of the metal complex anion Q21 and cyanine dye cation D-8-6 (Comparative Compound No. 202). When an attempt was made to apply the solution using a solution, the solution could not be applied due to the low solubility of the salt-forming dye. The results are shown in Table 12.

<Sample 23>
In the same manner as in Sample 21, 2 of the cyanine dye salt (Comparative Compound No. 203) of the anion Q22 and the cyanine dye cation D-6-1 constituting the highly soluble salt of the metal complex (Q22 salt) is used. When 2,3,3-tetrafluoropropanol (TFP) solution was used for coating, only 0.5 wt% of the salt-forming dye was dissolved, and a sufficient film thickness could not be obtained. The results are shown in Table 12.

<Sample 24>
In the same manner as in Sample 21, perchlorate (ClO ₄ ) of the cyanine dye cation D-6-1 (Comparative Compound No. 204 above), 2,2,3,3-tetrafluoropropanol (TFP) 3 wt% The solution was used for coating and dried to obtain a dye film of 190 nm. The coating time was 30 seconds. The film was irradiated with light from an 80,000 lux Xe lamp, but the film was colorless and transparent in 20 hours. The results are shown in Table 12.

<Sample 25>
In the same manner as in Sample 21, a diacetone alcohol solution of a highly soluble salt of the above metal complex (Q22 salt) and a cyanine dye salt of the cyanine dye cation D-3-4 (Comparative Compound No. 205) was used. Application and drying were performed to obtain a uniform dye film of 200 nm. The application time required 60 seconds. The film was irradiated with light from an 80,000 lux Xe lamp, but 95 wt% of the dye remained even after 100 hours. The results are shown in Table 12.

<Sample 26>
In the same manner as in Sample 21, dian salt of cyanine dye salt (Comparative Compound No. 203) of anion Q22 and cyanine dye cation D-6-1 constituting the highly soluble metal complex salt (Q22 salt) was prepared. Coating was performed using an acetone alcohol solution, followed by drying to obtain a uniform dye film of 190 nm. The application time required 60 seconds. When this film was irradiated with light from an 80,000 lux Xe lamp, only 100% of the dye remained after 100 hours. The results are shown in Table 12.

As is apparent from Tables 11 and 12, the light-stabilized cyanine dye of the present invention can be applied to only a solvent having a high evaporation rate, such as TFP. Is easily dissolved, and the coating time is greatly reduced to 1/2. In particular, monomethine cyanine dyes and trimethine cyanine dyes, which are one of the short-wavelength recording dyes expected to be used in the future, have much higher light resistance than conventional light-stabilized dyes that use a quencher anion as a counter ion. Could be improved. The counterion is _{^{ClO 4 -, BF 4 -,}} I - although cyanine dyes very easily soluble in TFP such, easily fade by light irradiation, unpractical causes deteriorated.

  In addition, the equivalent result was obtained also with other exemplary compounds of this invention of Table 2.

Example 5
[Creation of optical recording disc (for CD-R)]
Polycarbonate was injection molded to obtain a substrate having a diameter of 120 mm and a thickness of 1.2 mm. On the recording layer forming surface of the substrate, a tracking groove having a groove pitch of 1.6 μm, a groove width of 0.48 μm, and a groove depth of 160 nm was formed.

On the above polycarbonate resin substrate, Exemplified Compound No. 1 was prepared by spin coating.
A recording layer containing 27 (D-3-8 · Q1) was formed to a thickness of 2000 A (200 nm). As a coating solution in this case, a 2,2,3,3-tetrafluoropropanol 1.0 wt% solution was used. Next, an Au reflective film is formed on the recording layer to a thickness of 850A by sputtering, and a transparent protective layer (film thickness 5 μm) of an ultraviolet curable acrylic resin is formed. 31.

Disc sample No. In 31, further as cyanine dyes, ClO the D-3-8 ₄ ^- disk sample except that a recording layer is formed by using a material obtained by adding 40 wt% relative to the salt the dye in the same manner No. 32 was produced.

  The disk sample No. On the other hand, when recording characteristics were examined at a linear velocity of 1.2 m / sec using a semiconductor laser (oscillation wavelength 780 nm), recording was possible with a laser power of 6.0 mW. Further, when the reproduction characteristics were examined using a semiconductor laser (oscillation wavelength 780 nm), the reflectance was 70% or more, the modulation degree was 68%, and Rtop was 67%. This was found to be an optical recording disk showing good characteristics in accordance with the Orange Book standard.

  Disc sample No. 32, disk sample No. When recording characteristics were examined in the same manner as in No. 31, recording was possible with a laser power of 5.7 mW. Also, the disk sample No. When the reproduction characteristics were examined in the same manner as in No. 31, the reflectivity was 70% or more, the modulation degree was 70%, and Rtop was 68%. This was found to be an optical recording disk showing good characteristics in accordance with the Orange Book standard.

Example 6
[Creation of optical recording disk (for DVD-R)]
Polycarbonate was injection molded to obtain a substrate having a diameter of 120 mm and a thickness of 0.6 mm. On the recording layer forming surface of the substrate, a tracking groove having a groove pitch of 0.8 μm, a groove width of 0.30 μm, and a groove depth of 140 nm was formed.

  On the above polycarbonate resin substrate, Exemplified Compound No. 1 was prepared by spin coating. A recording layer containing 103 (D-7-7 · Q9) was formed to a thickness of 1000 A (100 nm). As a coating solution in this case, a 1.2 wt% solution of 2,2,3,3-tetrafluoropropanol was used. Next, an Au reflective film is formed on the recording layer to a thickness of 850A by sputtering, and a transparent protective layer (film thickness of 5 μm) of an ultraviolet curable acrylic resin is formed, with this protective film facing inward. Adhesive was used for bonding, and this was attached to disk sample no. 33.

Disc sample No. In 33, further as cyanine dye, D-8-6 of ClO ₄ ^- disk sample as in addition to forming a recording layer using what the salt was added 30 wt% relative to the dye No. 34 was produced.

  The disc sample No. of the optical recording disc produced in this way was used. 33, no. When the recording / reproducing characteristics were examined using a laser (oscillation wavelength of 635 nm) at a linear velocity of 3.8 m / sec, a good characteristic was shown.

Example 7
In Example 5, the recording layer was 1.2% by weight of 2,2,3,3-tetrafluoropropanol in which the light-stabilized cyanine dye and the cyanine dye of the present invention were used in combinations and quantitative ratios as shown in Table 13. Disc samples were prepared in the same manner except that each solution was formed, and recording / reproduction characteristics (disc characteristics) were examined under the same conditions as in Example 5.

For recording characteristics, the optimum recording power was examined. Regarding the reproduction characteristics, the reflectance, Rtop, modulation degree (I ₁₁ Mod), and jitter (Jitter) were examined. The reflectance was 70% or more for all samples. Table 13 shows Rtop, modulation factor, jitter, and optimum recording power. Jitter shows both land and pit.

  From Table 13, it was found that all of the optical recording disks showed good characteristics based on the Orange Book standard.

Example 8
A disk sample was prepared in the same manner as in Example 7 except that an Ag reflective film was used instead of the Au reflective film, and the recording / reproducing characteristics were examined in the same manner as in Example 7.

  The reflectance was 70% or more for all samples. Table 14 shows Rtop, modulation factor, jitter, and optimum recording power.

  From Table 14, it was found that all of the optical recording disks showed good characteristics in conformity with the Orange Book standard.

Example 9
In Example 7, a 1.0 wt% solution of 2,2,3,3-tetrafluoropropanol in which the recording layer was used in the following combinations and quantitative ratios of the light stabilizing dye of the present invention and the cyanine dye. A disk sample (Nos. 91 to 94) was produced in the same manner except that each was used, and the recording / reproducing characteristics were examined in the same manner as in Example 7. As a result, the same characteristics as in Example 7 were obtained. It turns out that it is obtained.
Sample No.
91 Compound No. 87 / Compound No. 110 / (D-4-6) · ClO ₄ = 60/10/30 (weight ratio),
92 Compound No. 85 / (D-4-6) · ClO ₄ / (D-10-4) · ClO ₄ = 60/35/5 (weight ratio)
93 Compound No. 94 / (D-4-6) · BF ₄ / (D-9-5) · ClO ₄ = 50/40/10 (weight ratio),
94 Compound No. 94 / (D-4-6) .ClO ₄ /(D-9-5).ClO ₄ = 65/35/10 (weight ratio).

Example 10
A disk sample was prepared in the same manner as in Example 9 except that an Ag reflective film was used instead of the Au reflective film, and the recording / reproducing characteristics were examined in the same manner as in Example 7. As in Example 8, It was found that good characteristics can be obtained.

Claims (4)

The substituted benzenedithiol metal complex anion represented by the following formula (1) as a counter ion, have a recording layer containing a cyanine dye and form a substituted benzenedithiol metal complex anion and the ionic compound, the recording layer An optical recording medium formed by applying a solution using a solvent having a vapor pressure at 25 ° C. of 5.3 Torr or higher .

The optical recording medium according to claim 1, wherein the solvent is 2,2,3,3-tetrafluoropropanol . A cyanine dye having a substrate and contained in a recording layer provided on the substrate is a cyanine dye kaolin represented by the following formula (3) and a substituted benzenedithiol metal complex anion represented by the following formula (1): The optical recording medium according to claim 1 , wherein the optical recording medium is a dye comprising a salt.

[Wherein, Q ₁ and Q ₂ each represents an atomic group for forming a 5-membered nitrogen-containing heterocycle which may have a condensed ring. R ₂₁ and R ₂₂ each represents an alkyl group. L represents a methine chain for completing a cyanine dye. ] The optical recording medium according to claim 1, wherein the recording layer further contains one or more other dyes.