JPH0472712B2 - - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to optical recording media, particularly heat mode optical recording media. Prior Art Optical recording media have the characteristic that the recording medium does not deteriorate due to wear since the medium and the writing or reading head are not in contact with each other, and for this reason, research and development of various optical recording media are being carried out. Among such optical recording media, heat mode optical recording media are being actively developed because they do not require image processing in a darkroom. This heat mode optical recording medium is an optical recording medium that uses recording light as heat. One example is a heat mode optical recording medium that uses recording light such as a laser to melt or remove a part of the medium, which is called a pit. Some devices perform writing by forming small holes, record information using the pits, and read out information by detecting the pits with a readout light. Examples of such pit-forming media include media in which a recording layer made of a light-absorbing dye is formed on a substrate and pits are formed by melting the dye, and media in which pits are formed by melting the dye, and self-oxidizing media such as nitrocellulose. A recording layer containing a thermoplastic resin and a light-absorbing dye is formed, and a recording layer that forms pits by decomposing nitrocellulose, etc., or a recording layer consisting of a thermoplastic resin and a light-absorbing dye is formed, and the resin and Some are known that form pits by melting pigments. By the way, cyanine dyes are known as one of the light-absorbing dyes. However, when forming a recording layer using a cyanine dye, the dye is bleached due to repeated irradiation with readout light during readout after writing.
This method has the drawback that the readout C/N ratio is poor, that is, so-called reproduction deterioration is large, and it is not suitable for practical use. OBJECTS OF THE INVENTION The main object of the present invention is to provide an optical recording medium having a recording layer containing a cyanine dye, which has a high reproduction C/N ratio and improved reproduction deterioration. These objects are achieved by the invention described below. That is, the present invention provides a cyanine dye having an indolenine ring to which an aromatic ring may be fused, or a recording layer containing the cyanine dye and a resin, and further containing a compound represented by the following general formula [] on a substrate. , an optical recording medium characterized in that deterioration of the cyanine dye due to reproduction light is prevented. General formula [] {In the above general formula [], M represents Pt, Ni or Pd, and X ₁ , X ₂ , X ₃ and X ₄ each represent O or S. } Specific Structure of the Invention The specific structure of the present invention will be described in detail below. The recording layer of the optical recording medium of the present invention contains a cyanine dye having an indolenine ring to which an aromatic ring may be fused. Among such cyanine dyes, those represented by the following formula [] are preferred. Formula [] Φ-L=Ψ (X ^- ) _n In the above formula [], Φ and Ψ represent an indolenine ring to which an aromatic ring, such as a benzene ring, naphthalene ring, or phenanthrene ring, may be fused. These Φ and Ψ are usually the same, but they may differ from each other because the fused state is different, or one of them is a thiazole ring, oxazole ring, selenazole ring, imidazole ring, pyridine ring, etc. good. Various substituents may be fused to these rings. Note that in Φ, the nitrogen atom in the ring has a positive charge, and in Ψ, the nitrogen atom in the ring is neutral. The skeleton rings of these Φ and Ψ are preferably those represented by the following formulas [Φ] to [Φ]. In addition, in the following, the structure is shown in the form of Φ. In these various rings, the group R ₁ bonded to the nitrogen atom in the ring is a substituted or unsubstituted alkyl group or aryl group. The group R ₁ bonded to the nitrogen atom in such a ring
There is no particular restriction on the number of nitrogen atoms in . In addition, when this group further has a substituent, examples of the substituent include a sulfonic acid group, an alkylcarbonyloxy group, an alkylamido group, an alkylsulfonamide group, an alkoxycarbonyl group, an alkylamino group, an alkylcarbamoyl group, It may be any of an alkylsulfamoyl group, a hydroxyl group, a carboxy group, a halogen atom, etc. In addition, when m described below is 0, the group R ₁ bonded to the nitrogen atom in Φ is a substituted alkyl or aryl group and has a negative charge. Furthermore, two substituents are present at the 3-position of the fused or non-fused indolenine ring [Φ] to [Φ].
It is preferable that R ₂ and R ₃ are bonded. in this case,
The two substituents R ₂ and R ₃ bonded to the 3-position are:
Preferably, it is an alkyl group or an aryl group. Among these, unsubstituted alkyl groups having 1 or 2 carbon atoms, particularly 1, are preferred. On the other hand, another substituent R ₄ may be bonded to a predetermined position in the ring represented by Φ and Ψ. Such substituents include alkyl groups,
It may be a variety of substituents such as an aryl group, a heterocyclic residue, a halogen atom, an alkoxy group, an alkylthio group, an alkyloxycarbonyl group, an alkylcarbonyloxy group, and a carboxylic acid group. Then, the number of these substituents (p, q, r,
s, t) are usually 0 or about 1 to 4. Note that when p, q, r, s, and t are 2 or more, a plurality of R ₄ may be different from each other. In addition, those having fused or non-fused indolenine rings of the formulas [Φ] to [Φ] have superior coating properties and stability, exhibit extremely high reflectance, and are highly readable. The C/N ratio is extremely high, and reproduction deterioration etc. are also extremely reduced. On the other hand, L represents a linking group for forming a mono-, di-, tri- or tetracarbocyanine dye, and is particularly preferably one of the formulas [L] to [L-]. Here, Y represents a hydrogen atom or a monovalent group. In this case, monovalent groups include lower alkyl groups such as methyl groups, lower alkoxy groups such as methoxy groups, dimethylamino groups, diphenylamino groups, methylphenylamino groups, morpholino groups, imidazolidine groups, and ethoxycarbonylpiperazine groups. Preferable examples include a di-substituted amino group such as, an alkylalbonyloxy group such as an acetoxy group, an alkylthio group such as a methylthio group, a cyano group, a nitro group, and a halogen atom such as Br and Cl. Furthermore, R ₈ and R ₉ each represent a hydrogen atom or a lower alkyl group such as a methyl group. And l is 0 or 1. In addition, among these formulas [L] to [L-], tricarbocyanine linking groups, especially formulas [L],
[L] is preferred. Furthermore, X ^- is an anion, preferred examples of which are I ^- , Br ^- , ClO ₄ ^- , BF ₄ ^- ,

【formula】

[Formula] etc. can be mentioned. Note that m is 0 or 1, but when m is 0, R ₁ of Φ usually has a negative charge and becomes an inner salt. Next, specific examples of the cyanine dye of the present invention will be given, but the present invention is not limited to these.

【table】

[Table] Such dyes can be easily synthesized according to the method described in books such as Dai Organic Chemistry (Asakura Shoten) Nitrogen-Containing Heterocyclic Compounds, page 432. That is, first, the corresponding Φ′−CH ₃ (Φ′ is the above Φ
represents the ring corresponding to . ) with excess R ₁ I (R ₁ is an alkyl group or an aryl group),
R ₁ is introduced into the nitrogen atom in Φ' to obtain Φ-CH ₃ I ^- . Next, this may be subjected to dehydration condensation with an unsaturated dialdehyde or an unsaturated hydroxyaldehyde using an alkali catalyst. Further, such a dye is usually contained in the recording layer in the form of a monomer, but may be contained in the form of a polymer if necessary. In this case, the polymer has two or more molecules of a dye, and may be a condensate of these dyes. For example, single or co-condensates of the above dyes having one or more functional groups such as -OH, -COOH, -SO ₃ H, etc., or with these, dialcohols, dicarboxylic acids, or their salts. There are cocondensation components such as diamines, di- and triisocyanates, diepoxy compounds, acid anhydrides, dihydrazides, and diiminocarbonates, and cocondensation products with other pigments. Alternatively, the dye having the above functional group may be crosslinked with a metal crosslinking agent alone or together with a spacer component or other dye. In this case, the metal crosslinking agents include alkoxides of titanium, zircon, aluminum, etc., chelates of titanium, zircon, aluminum, etc. (e.g., β-diketones, ketoesters, hydroxycarboxylic acids and their esters, ketoalcohols, aminoalcohols, enols) acylates of titanium, zircon, aluminum, etc.). Furthermore, -OH group, -OCOR group, and -
One or more dyes having at least one COOR group (wherein R is a substituted or unsubstituted alkyl group or aryl group);
Alternatively, it is also possible to use a compound in which this and other spacer components or other dyes are bonded through a -COO- group through a transesterification reaction. In this case, the transesterification reaction is preferably carried out using an alkoxide such as titanium, zircon, or aluminum as a catalyst. Additionally, the dyes described above may be bound to a resin. In such a case, a resin having a predetermined group is used, and the side chain of the resin is subjected to a condensation reaction, transesterification reaction, or crosslinking, as in the case of the polymer described above. The dyes are linked via a spacer component, etc., if necessary. Furthermore, the recording layer may contain resin. The resin used is preferably a self-oxidizing, depolymerizable or thermoplastic resin. Among these, thermoplastic resins that can be particularly preferably used include the following. () Polyolefin polyethylene, polypropylene, poly4-methylpentene-1, etc. () Polyolefin copolymer For example, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, ethylene-acrylic acid copolymer, ethylene-propylene copolymer, ethylene-butene-1 copolymer,
Ethylene-maleic anhydride copolymer, ethylene propylene terpolymer (EPT), etc. In this case, the polymerization ratio of the comonomers can be arbitrary. () Vinyl chloride copolymer For example, vinyl acetate-vinyl chloride copolymer,
Vinyl chloride-vinylidene chloride copolymer, vinyl chloride-maleic anhydride copolymer, copolymer of acrylic acid ester or methacrylic acid ester and vinyl chloride, acrylonitrile-vinyl chloride copolymer, vinyl chloride ether copolymer,
Ethylene or propylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer with vinyl chloride graft polymerized, etc. In this case, the copolymerization ratio can be arbitrary. () Vinylidene chloride copolymer Vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-vinyl chloride-acrylonitrile copolymer, vinylidene chloride-butadiene-vinyl halide copolymer, etc. In this case, the copolymerization ratio can be arbitrary. () Polystyrene () Styrene copolymer For example, styrene-acrylonitrile copolymer (AS resin), styrene-acrylonitrile-
Butadiene copolymer (ABS resin), styrene-
Maleic anhydride copolymer (SMA resin), styrene-acrylic acid ester-acrylamide copolymer, styrene-butadiene copolymer (SBR), styrene-vinylidene chloride copolymer,
Styrene-methyl methacrylate copolymer, etc. In this case, the copolymerization ratio can be arbitrary. () Styrene type polymers For example, α-methylstyrene, p-methylstyrene, 2,5-dichlorostyrene, α,β-
Vinylnaphthalene, α-vinylpyridine, acenaphthene, vinylanthracene, etc., or copolymers thereof, such as copolymers of α-methylstyrene and methacrylic acid ester. () Coumarone-indene resin A copolymer of coumaron-indene-styrene. () Terpene resin or picolite For example, terpene resin which is a polymer of limonene obtained from α-pinene, or picolite obtained from β-pinene. () Acrylic resin Particularly preferred is one containing an atomic group represented by the following formula. formula In the above formula, R ₁₀ represents a hydrogen atom or an alkyl group, and R ₂₀ represents a substituted or unsubstituted alkyl group. In this case, in the above formula, R ₁₀ is a hydrogen atom or a carbon atom number of 1 to 1.
4 is preferably a lower alkyl group, particularly a hydrogen atom or a methyl group. Further, R ₂₀ may be a substituted or unsubstituted alkyl group, but the alkyl group preferably has 1 to 8 carbon atoms, and when R ₂₀ is a substituted alkyl group, the alkyl group preferably has 1 to 8 carbon atoms. The substituent for the group is preferably a hydroxyl group, a halogen atom, or an amino group (particularly a dialkylamino group). The atomic group represented by the above formula may form a copolymer with other repeating atomic groups to constitute various acrylic resins, but usually one type of atomic group represented by the above formula is used. Alternatively, an acrylic resin is formed by forming a homopolymer or copolymer having two or more repeating units. (xi) Polyacrylonitrile (xii) Acrylonitrile copolymer For example, acrylonitrile-vinyl acetate copolymer, acrylonitrile-vinyl chloride copolymer, acrylonitrile-styrene copolymer, acrylonitrile-vinylidene chloride copolymer, acrylonitrile-vinylpyridine copolymer Polymer, acrylonitrile methyl methacrylate copolymer,
Acrylonitrile-butadiene copolymer, acrylonitrile-butyl acrylate copolymer, etc. In this case, the copolymerization ratio can be arbitrary. () Diacetone acrylamide polymer Diacetone acrylamide polymer made by reacting acetone with acrylonitrile. () Polyvinyl acetate () Vinyl acetate copolymer For example, a copolymer with acrylic acid ester, vinyl ether, ethylene, vinyl chloride, etc. The copolymerization ratio may be arbitrary. () Polyvinyl ether For example, polyvinyl methyl ether, polyvinyl ethyl ether, polyvinyl butyl ether, etc. () Polyamide In this case, polyamides include nylon 6, nylon 6-6, nylon 6-10, nylon 6-12, nylon 9, nylon 11, nylon
In addition to regular homonylon such as 12 and nylon 13,
Nylon 6/6-6/6-10, Nylon 6/6
-6/12, nylon 6/6-6/11, or modified nylon as the case may be. () Polyester For example, oxalic acid, succinic acid, maleic acid,
Various dibasic acids such as aliphatic dibasic acids such as adipic acid and sebastenic acid, or aromatic dibasic acids such as isophthalic acid and terephthalic acid, ethylene glycol, tetramethylene glycol,
Condensates and co-condensates with glycols such as hexamethylene glycol are suitable. Among these, condensates of aliphatic dibasic acids and glycols and cocondensates of glycols and aliphatic dibasic acids are particularly suitable. Furthermore, for example, glyptal resin, which is a condensate of phthalic anhydride and glycerin, can be used as a fatty acid,
Modified glyptal resins that are esterified with natural resins and the like are also preferably used. () Polyvinyl acetal resin Both polyvinyl formal and polyvinyl acetal resin obtained by acetalizing polyvinyl alcohol are preferably used. In this case, the degree of acetalization of the polyvinyl acetal resin can be arbitrary. () Polyurethane resin Thermoplastic polyurethane resin with urethane bonds. Particularly suitable are polyurethane resins obtained by condensation of glycols and diisocyanates, particularly polyurethane resins obtained by condensation of alkylene glycol and alkylene diisocyanate. (xi) Polyether Styrene-formalin resin, ring-opening polymer of cyclic acetal, polyethylene oxide and glycol, polypropylene oxide and glycol, propylene oxide-ethylene oxide copolymer, polyphenylene oxide, etc. (xii) Cellulose derivatives such as nitrocellulose, acetylcellulose, ethylcellulose, acetylbutylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, methylcellulose,
Various esters and ethers of cellulose, such as ethylhydroxyethylcellulose, and mixtures thereof. () Polycarbonate For example, various polycarbonates such as polydioxydiphenylmethane carbonate and dioxydiphenylpropane carbonate. (x) Ionomer Na, Li, methacrylic acid, acrylic acid, etc.
Zn, Mg salt, etc. () Ketone resin For example, a condensate of a cyclic ketone such as cyclohexanone or acetophenone and formaldehyde. () Xylene resin For example, a condensate of m-xylene or mesitylene with formalin, or a modified product thereof. () Petroleum resins _C5 type, _C9 type, _C5 - _C9 copolymer type, dicyclopentadiene type, or copolymers or modified products thereof. () A blend of two or more of the above () to (), or a blend with other thermoplastic resins. Note that the molecular weight of the self-oxidizing, thermoplastic, etc. resin may vary. Such self-oxidizing, thermoplastic resin and the above-mentioned dye are usually formed in a layer at a weight ratio of 1:0.1 to 100 over a wide range. Such a recording layer contains a quencher represented by the above general formula []. This reduces reproduction deterioration of the S/N ratio due to repeated irradiation with readout light. In addition, light resistance is improved by storage in a bright room. In the above general formula [], M is Pt, Ni, or Pd, and X ₁ to X ₄ may be the same or different, and each represents O or S. The compound represented by the general formula [] is
For example, it is synthesized by the method described in JP-A-57-161744. Specific examples of the compound represented by the general formula [] are listed below.

[Ciasorb UV-1084 manufactured by Nippon Cyanamid Co., Ltd.]

Q2′ Nickel bis(octyl phenyl) sulfide [Fuero AM-101 Nissan Fuero Organic Chemical Co., Ltd.
] DP is D7 and D105 cross-linked with di-i-propoxybis(acetylacetonato) titanium, DR is PMMA (number average molecular weight 10,000),
D8 is linked by transesterification.

[Table] From the results shown in Table 1, the effects of the present invention are clear. Example 2 Using media Nos. 4, 5, 6, 8, 9, and 10 of Example 1, writing was performed in the same manner as in Example 1, and then the media were heated at 150°C for 15 seconds using an infrared heater. It was confirmed that each medium could be successfully erased and rewritten many times.

Claims (1)

[Scope of Claims] 1. A recording layer containing a cyanine dye having an indolenine ring to which an aromatic ring may be fused, or this cyanine dye and a resin, and further containing a compound represented by the following general formula [] is provided on a substrate. An optical recording medium characterized in that the cyanine dye is prevented from being degraded by reproduction light. General formula [] {In the above general formula [], M represents Pt, Ni or Pd, and X ₁ , X ₂ , X ₃ and X ₄ each represent 0 or S. } 2. The optical recording medium according to claim 1, wherein the cyanine dye is a compound represented by the following general formula []. General formula [] Φ-L=Ψ (X ^- ) _n {In the above general formula [], Φ and Ψ each represent an indolenine ring to which an aromatic ring may be fused, and L is mono-, di- , represents a linking group for forming a tri- or tetracarbocyanine dye, X ^- represents an anion, and m is 0 or 1. }