(19)
(11)EP 1 056 078 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
12.04.2006 Bulletin 2006/15

(21)Application number: 00304521.8

(22)Date of filing:  26.05.2000
(51)International Patent Classification (IPC): 
G11B 7/24(2006.01)

(54)

Process for preparation of optical information recording disc, optical information recording disc and dye solution

Herstellungsverfahren einer optischen Disc, optische Disc und Farblösung

Procécé de préparation d'une disque optique, disque optique et solution de colorant


(84)Designated Contracting States:
DE FR GB

(30)Priority: 26.05.1999 JP 14640099
26.05.1999 JP 14640199
08.06.1999 JP 16084899
14.06.1999 JP 16730499
14.06.1999 JP 16740599

(43)Date of publication of application:
29.11.2000 Bulletin 2000/48

(73)Proprietor: FUJI PHOTO FILM CO., LTD.
Minami-Ashigara-shi, Kanagawa-ken 250-0123 (JP)

(72)Inventors:
  • Usami, Yoshihisa
    Odaware-shi, Kanagawa, 250-0001 (JP)
  • Inagaki, Yoshio
    Minami-ashigara-shi, Kanagawa, 250-0123 (JP)

(74)Representative: Calamita, Roberto 
Frank B. Dehn & Co., European Patent Attorneys, 179 Queen Victoria Street
London EC4V 4EL
London EC4V 4EL (GB)


(56)References cited: : 
EP-A- 0 272 933
US-A- 5 316 814
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    FIELD OF THE INVENTION



    [0001] This invention relates to an optical information recording medium such as a compact disc (namely, CD), a digital video disc (namely, DVD), a recordable compact disc (namely, CD-R) or a recordable digital video disc (namely, DVD-R).

    BACKGROUND OF THE INVENTION



    [0002] An optical information recording medium on which information can be only once recorded by means of a laser beam (i.e., an optical disc of write-once type) is known as a recordable compact disc (CD-R), and at present is widely used in practice. The optical disc of CD-R type generally has a multi-layered structure typically comprising a disc-shaped transparent substrate (support), a recording layer comprising an laser light-sensitive organic dye (often referred to as "recording dye layer"), a light-reflecting layer comprising a metal (hereinafter, often referred to as "metallic light-reflecting layer", or simply "reflecting layer"), and optionally a protective layer made of resin overlaid in order.

    [0003] A demand for large recording capacity has recently increased, but an optical disc of CD-R type does not have satisfactorily large information-recording capacity. Therefore, an optical disc having satisfactorily large information-recording capacity has been studied and proposed. For example, a recordable DVD (i.e., recordable digital video disc, DVD-R), in which information can be recorded on and read out from by means of a laser beam having a shorter wavelength than that for CD-R, has been developed. The optical disc of DVD-R type is formed by laminating two composites having a layered structure. Each of the layered composites comprises a transparent disc substrate provided with a guide groove (i.e., pre-groove) for tracking of the laser beam, a recording layer comprising an organic dye, a light-reflecting layer, and a protective layer arranged in order. The layered composites are combined with an adhesive so that the recording layers would be placed inside. Otherwise, the optical disc of DVD-R type is formed by combining a protective disc plate and the layered composites comprising a substrate, a recording layer, a light-reflecting layer, and a protective layer arranged in order.

    [0004] For writing (i.e., recording) and reading (i.e., reproducing) the information, a CD-R is irradiated with a laser beam having a wavelength in the range of 770 to 790 nm, typically approx. 780 nm, while a DVD-R is irradiated with a laser beam of visible wavelength region (generally having a wavelength of 600 to 700 nm, typically approx. 650 nm). By the irradiation of the laser beam, the irradiated area of the recording dye layer is locally heated to change its physical or chemical characteristics. Thus, pits are formed in the irradiated area of the recording layer. Since the optical characteristics of the formed pits are different from those of the surrounding area having been not irradiated, the digital information is recorded. The recorded information can be read by a reproducing procedure generally comprising the steps of irradiating the recording layer with a relatively weak laser beam having the same wavelength as that employed in the recording procedure, and detecting the light-reflection difference between the pits and their surrounding areas.

    [0005] The recording dye layer of DVD-R or CD-R is generally formed by dissolving a laser light-sensitive dye in a solvent to prepare a dye solution and coating the dye solution on a transparent substrate disc having a pre-groove on its surface by spin-coat procedure. In the spin-coat procedure, the dye solution is continuously dropped on the surface of the substrate under rotation. The dropped dye solution is centrifugally spread out, and an excessive portion of the dye solution is splashed off from the edge of the substrate. The dye solution remaining on the substrate is dried by evaporation of the solvent to form a thin recording dye layer on the substrate.

    [0006] The solvent for the dye solution naturally should dissolve therein the laser light-sensitive dye at a relatively high solubility level, but essentially should not dissolve the material of the substrate. Most of the known solvents in which the dye is well soluble dissolve the surface of the substrate to damage the pre-groove. Most of the known solvents which are essentially inert to the substrate cannot dissolve the dye at a satisfactory level.

    [0007] United States Patent No. 4,832,992 discloses that a fluorine-containing compound is favorably employed as the solvent for the preparation of the dye solution. The fluorine-containing compound has excellent properties as a solvent for the preparation of a dye solution. For example, most laser light-sensitive dyes are well soluble in the fluorine-containing compounds while a substrate made of polycarbonate is not damaged by the fluorine-containing compounds. The U.S. Patent further discloses a representative fluorinated alcohol, namely, 2,2,3,3-tetrafluoro-1-propanol.

    [0008] Thus, the fluorinated alcohol is a favorable solvent for the preparation of a dye solution to be coated on a substrate disc made of polycarbonate. However, our detailed study has revealed that it takes a relatively long time of period for evaporating the fluorinated alcohol from the dye solution coated on the substrate disc to produce a uniform thin recording dye layer. The requirement of such long time of period for drying the coated dye solution is disadvantageous for mass production of optical recording discs.

    [0009] Accordingly, the present inventors have made studies to find a group of new solvents which can dissolve the laser light-sensitive dye at a relatively high level, which is essentially inert to the substrate material, particularly, polycarbonate, and which evaporates rapidly at an ambient temperature.

    [0010] In the course of the studies, the inventors have tried to employ an organic solvent comprising a fluorinated cyclic alkane or alkene as a solvent for preparing a dye solution for the manufacture of a recording dye layer of an optical information recording medium.

    [0011] The fluorinated hydrocarbon such as fluorinated cyclic alkane or alkene is described for the use as a detergent in Japanese Patent Provisional Publication Nos. 10-316596, 10-316597 and 10-316598. These publications further describe that a 4- to 6-membered fluorinated cyclic alkane or alkene, particularly 1,1,2,2,3,3,4-heptafluorocyclopentane is preferred.

    [0012] EP-A-0272933 discloses a method for forming an optical recording layer using a coating solution of a dye in a solvent containing a fluorine-containing compound,

    SUMMARY OF THE INVENTION



    [0013] Accordingly, it is the object of the present invention to provide a laser light-sensitive dye solution which can dissolve the dye at a relatively high level, which is essentially inert to the substrate material, particularly, polycarbonate, and which evaporates rapidly at an ambient temperature.

    [0014] It is another object of the invention to provide a process for the production of an optical information recording medium which is enable to produce the recording medium for a shortened drying period.

    [0015] The present invention resides in a process for the preparation of an optical information recording disc comprising the steps of coating a dye solution on a transparent substrate disc and drying the coated dye solution, in which the dye solution is a solution of a laser-light sensitive organic dye dissolved in an organic solvent comprising 1,1,2,2,3,3,4-heptafluorocyclopentane.

    [0016] The invention furthermore resides in a dye solution which comprises a laser-light sensitive organic dye dissolved in an organic solvent comprising 1,1,2,2,3,3,4-heptafluorocyclopentane.

    [0017] In the dye solution of the invention, the fluorinated cyclic alkane is 1,1,2,2,3,3,4-heptafluorocyclopentane, which is illustrated by the following formula (I).



    [0018] The dye solution of the present invention is preferably prepared by the steps of mixing the organic dye and the solvent and keeping the resulting mixture at a temperature of higher than 45°C but lower than a boiling temperature of the solvent by at least 10°C for a period of 5 minutes to 2 hours.

    [0019] The solvent for the preparation of the dye solution of the invention will comprise 1,1,2,2,3,3,4-heptafluorocyclopentane and may comprise one or more organic solvents or liquids. For instance, the solvent comprises 1,1,2,2,3,3,4-heptafluorocyclopentane and may comprise an organic liquid which has a boiling point higher than that of the fluorinated cyclic alkane, which is essentially inert to the substrate, and in which the dye is soluble, in a volume ratio of 99:1 to 51:49. The organic liquid preferably has a boiling point of lower than 250°C but higher than that of 1,1,2,2,3,3,4-heptafluorocyclopentane by at least 10°C. Examples of the organic liquids include an aliphatic ketone, an aliphatic hydrocarbon, an alicyclic hydrocarbon, a carboxylic acid ester, an aliphatic ether, and an alcohol. Preferred organic liquids are a fluorinated alcohols having the formulas of CF3CH2OH, HCF2CF2CH2OH, H(CF2CF2) 2CH2OH, and H(CF2CF2)3CH2OH. A ketoalcohol (e.g., diacetone alcohol) is also preferred.

    [0020] The organic solvent comprises 1,1,2,2,3,3,4-heptafluorocyclopentane and may comprise an organic liquid which has a solubility for the dye higher than that of 1,1,2,2,3,3,4-heptafluorocyclopentane and which is active to the substrate, in a volume ratio of 99.9:0.1 to 80:20. Examples of the organic liquids include a halogenated aliphatic hydrocarbon, an aromatic hydrocarbon, a ketone, a sulfoxide, an amide, a carboxylic acid ester, an ether, and a nitrile. Preferred organic liquid is a halogenated aliphatic hydrocarbon such as dichloromethane, dichloroethane, or tetrachloroethane. Acetone is also preferred.

    [0021] The solvent comprises 1,1,2,2,3,3,4-heptafluorocyclopentane and may comprise a fluorinated alcohol in a volume ratio of 50:50 to 1:99. Preferred fluorinated alcohol is 2,2,3,3-tetrafluoro-1-propanol.

    DETAILED DESCRIPTION OF THE INVENTION



    [0022] The optical information recording disc prepared by the process of the invention has a recording dye layer formed employing the specifically selected laser light-sensitive dye solution. The recording disc may be of CD-R type and DVD-R type. In the present specification, the process of the invention is explained with respect to an optical recording disc of CD-R type as an example.

    [0023] A typical optical disc of CD-R type comprises a transparent disc substrate having provided thereon a recording dye layer, a light-reflecting metal layer, and a protective resin layer overlaid in order. The process for producing an optical information recording disc comprising a transparent substrate, a recording dye layer, a light-reflecting metal layer and a protective resin layer, as an example, is described below in order.

    [0024] The transparent substrate disc can be made of any of materials known as those for the producing the substrate of the known optical information recording disc. Examples of the materials include glass; polycarbonate; acrylic resins such as polymethyl methacrylate; vinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymer; epoxy resins; amorphous polyolefins and polyesters. These materials can be employed in combination, if desired. The materials are molded to give a film or a rigid plate. Polycarbonate is most preferred from the viewpoints of anti-humidity, dimensional stability, and production cost.

    [0025] The substrate disc may have an undercoating layer on its surface of the recording layer side, so as to enhance surface smoothness and adhesion and to keep the recording dye layer from deterioration. Examples of the material for the undercoating layer include polymers such as polymethyl methacrylate, acrylate/methacrylate copolymer, styrene/maleic anhydride copolymer, polyvinyl alcohol, N-methylolacrylamide, styrene/vinyltoluene copolymer, chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate/vinyl chloride copolymer, ethylene/vinyl acetate copolymer, polyethylene, polypropylene and polycarbonate; and surface treating agents such as a silane-coupling agent.

    [0026] The undercoating layer can be formed by applying a coating solution (in which one or more of the above-mentioned materials are dissolved or dispersed) onto the surface of the substrate disc by the known coating methods such as spin-coat, dip-coat, and extrusion-coat. The undercoating layer generally has a thickness of 0.005 to 20 µm, preferably 0.01 to 10 µm.

    [0027] On the surface of the substrate or on the undercoating layer, a pregroove for tracking or giving address signals is formed. The pregroove is preferably formed directly on the surface of the substrate disc when the substrate disc is molded from polymer material by injection or extrusion.

    [0028] Alternatively, the pregroove can be provided on the surface of the substrate disc by placing a pregroove layer. The pregroove layer can be produced from a mixture of a monomer (such as monoester, diester, triester and tetraester) of acrylic acid (or its oligomer) and a photo-polymerization initiator. The pregroove layer can be produced by the steps of coating a precisely produced stamper with the mixture of the polymerization initiator and the monomer such as the above-mentioned acrylic ester, placing a substrate disc on the formed layer, and irradiating the formed layer with ultra-violet rays through the stamper or the substrate disc so as to cure the layer as well as to combine the cured layer and the substrate disc. The substrate disc to which the cured layer is attached is separated from the stamper, to give the desired substrate disc equipped with the pregroove layer. The thickness of the pregroove layer generally is in the range of 0.05 to 100 µm, preferably in the range of 0.1 to 50 µm.

    [0029] The pregroove formed on the substrate disc preferably has a depth in the range of 0.01 to 0.3 µm and a half-width of 0.2 to 0.9 µm. A depth of 0.15 to 0.2 µm of the pregroove is preferably adopted because such pre-groove can enhance the sensitivity without decreasing the light-reflection on the substrate. The optical disc having a recording dye layer formed on the deep pregroove and a light-reflection layer shows a high sensitivity, and hence is employable even in a recording system using a laser beam of low power. This means that a semiconductor laser of low output power can be employed, and the life of semiconductor laser can be prolonged.

    [0030] On the substrate provided with the pregroove, the recording dye layer is placed. The dye employed for the recording layer is not particularly restricted. Examples of the dye include cyanine dyes, phthalocyanine dyes, imidazoquinoxaline dyes, pyrylium/thiopyrylium dyes, azulenium dyes, squarilium dyes, metal (e.g., Ni, Cr) complex dyes, naphthoquinone dyes, anthraquinone dyes, indophenol dyes, merocyanine dyes, oxonol dyes, naphthoaniline dyes, triphenylmethane dyes, triallylmethane dyes, aminium/diimmonium dyes and nitroso compounds. Preferred are cyanine dyes, phthalocyanine dyes, azo dyes, azulenium dyes, squarilium dyes, oxonol dyes and imidazoquinoxaline dyes. Cyanine dyes, azo dyes and oxonol dyes are particularly preferred.

    [0031] Preferably, the cyanine dyes are compounds represented by the following formula (II). The cyanine dyes of the formula (II) are described in Japanese Patent Provisional Publication Nos. 4-175188, 10-151861, and 11-58973:



    [0032] In the formula (II), each of Z1 and Z2 independently is an atomic group for forming a 5- or 6-membered nitrogen-containing heterocyclic ring; each of R1 and R2 independently is an alkyl group; each of L1, L2, L3, L4 and L5 independently is a methine group which may have one or more substituents; each of n1 and n2 independently is 0, 1 or 2; each of p and q independently is 0 or 1, M1 is a charge-neutralizing counter ion; and m1 is a number of 0 or more which corresponds to an electron charge for neutralizing the cyanine dye.

    [0033] Examples of the nitrogen atom-containing heterocyclic rings (nuclei) containing the atomic group employing Z1 or Z2 include 3,3-dialkylindolenine nucleus, 3,3-dialkylbenzoindolenine nucleus, thiazole nucleus, benzothiazole nucleus, naphthothiazole nucleus, thiazoline nucleus, oxazole nucleus, benzooxazole nucleus, naphthooxazole nucleus, oxazoline nucleus, selenazole nucleus, benzoselenazole nucleus, naphthoselenazole nucleus, selenazoline nucleus, tellurazole nucleus, benzotellurazole nucleus, naphthotellurazole nucleus, tellurazoline nucleus, imidazole nucleus, benzoimidazole nucleus, naphthoimidazole nucleus, pyridine nucleus, quinoline nucleus, isoquinoline nucleus, imidazo[4,5-b]quinozaline nucleus, oxadiazole nucleus, thiadiazole nucleus, tetrazole nucleus, and pyrimidine nucleus. The above heterocyclic rings may be condensed with a benzene ring or a naphthoquinone ring.

    [0034] Each of the nitrogen atom-containing heterocyclic rings may have one or more substituents. The substituents may be composed of halogen, carbon, oxygen, nitrogen, sulfur, and hydrogen. Examples of the substituents (or substituent atoms) include a halogen atom, an alkyl group, an alkenyl group, an aryl group, an aralkyl group, a hetero-cyclic group, a cyano group, a nitro group, a mercapto group, a hydroxyl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an acylthio group, an acyloxy group, an amino group, an alkylamino group, a carbonamido group, a sulfonamido group, a sulfamoylamino group, an alkoxycarbonylamino group, an alkoxysulfonylanimo group, a ureido group, a thioureido group, an acyl group, an alkoxycarbonyl group, carbamoyl group, a sulfonyl group, a sulfinyl group, a sulfamoyl group, a carboxyl group (and its salt), and a sulfo group (and its salt). These groups can further have one or more substituents.

    [0035] The alkyl group represented by R1 or R2 preferably has 1-18 (more preferably 1-8, further preferably 1-6) carbon atoms and may be of a straight chain, a cyclic chain or a branched chain. The alkyl group of R1 or R2 may have a substituent group.

    [0036] The above-mentioned substituents are further described below.

    [0037] The halogen atoms can be fluorine, chlorine, or bromine.

    [0038] The alkyl group preferably is a linear chain, branched chain, or cyclic alkyl having 1 to 18 carbon atoms (preferably 1 to 8 carbon atoms), such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, 2-hydroxyethyl, 4-carboxybutyl, hexyl, or octyl.

    [0039] The alkenyl group preferably is linear chain, branched chain, or cyclic alkenyl having 2 to 18 carbon atoms (preferably 2 to 8 carbon atoms), such as vinyl, allyl, 1-propenyl, 2-pentenyl, 1,3-butadienyl, or 2-octenyl.

    [0040] The aryl group preferably has 6 to 10 carbon atoms, for instance, phenyl, naphthyl, 4-carboxyphenyl, 3-carboxyphenyl, 3,5-dicarboxyphenyl, 4-methanesulfonamidophenyl, and 4-butanesulfonamidophenyl.

    [0041] The aralkyl group preferably has 7 to 10 carbon atoms, for instance, benzyl and phenethyl.

    [0042] The heterocyclic group preferably is a 5- or 6-membered saturated or unsaturated heterocyclic group composed of carbon, nitrogen, oxygen, and/or sulfur, such as a ring of oxazole, benzoxazole, 5-carboxybenzoxazole, thiazole, imidazole, pyridine, sulforane, furan, thiophene, pyrazole, pyrrole, cumarone, or cumarince.

    [0043] The alkoxy group preferably has 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, for instance, methoxy, ethoxy, propoxy, and butoxy.

    [0044] The aryloxy group preferably has 6 to 10 carbon atoms, for instance, phenoxy and p-methoxyphenoxy.

    [0045] The alkylthio group preferably has 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, for instance, methylthio and ethylthio.

    [0046] The arylthio group preferably has 6 to 10 carbon atoms, for instance, phenylthio.

    [0047] The acyloxy group preferably has 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, for instance, acetoxy, propanoyloxy, pentanoyloxy, and octanoyloxy.

    [0048] The alkylamino group preferably has 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, for instance, methylamino, dimethylamino, diethylamino, dibutylamino, and octylamino.

    [0049] The carbonamido group preferably has 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, for instance, acetamido, propanoylamido, propanoylamino, pentanoylamino, octanoylamino, octanoylmethylamino, and benzamido.

    [0050] The sulfonamido group preferably has 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, for instance, methanesulfonamido, ethanesulfonamido, propanesulfonamido, butanesulfonamido, and benzenesulfonamido.

    [0051] The alkoxycarbonylamino preferably has 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, for instance, methoxycarbonylamino and ethoxycarbonylamino.

    [0052] The alkoxysulfonylamino preferably has 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, for instance, methoxysulfonylamino and ethoxysulfonylamino.

    [0053] The sulfamoylamino group preferably is sulfamoylamino or a sulfamoylamino having a substituent having 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, for instance, methylsulfamoylamino, dimethylsulfamoylamino, ethylsulfamoylamino, propylsulfamoylamino, and octylsulfamoylamino.

    [0054] The ureido group may have a substituent of 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, for instance, ureido, methylureido, N,N-dimethylureido, and octylureido.

    [0055] The thioureido group may have a substituent of 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, for instance, thioureido, methylthioureido, N,N-dimethylthioureido, and octylthioureido.

    [0056] The acyl group preferably has 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, for instance, acetyl, benzoyl, and propanoyl.

    [0057] The alkoxycarbonyl preferably has 2 to 18 carbon atoms, more preferably 2 to 8 carbon atoms, for instance, methoxycarbonyl, ethoxycarbonyl, and octyloxycarbonyl.

    [0058] The carbamoyl group may have a substituent of 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, for instance, carbamoyl, N,N-dimethylcarbamoyl, and N-ethylcarbamoyl.

    [0059] The sulfonyl group preferably has 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, for instance, methanesulfonyl, ethanesulfonyl, and benzenesulfonyl.

    [0060] The sulfinyl group preferably has 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, for instance, methanesulfinyl, ethanesulfinyl, and octanesulfinyl.

    [0061] The sulfamoyl group may be sulfamoyl or a sulfamoyl having 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, for instance, sulfamoyl, dimethylsulfamoyl, ethylsulfamoyl, butylsulfamoyl, octylsulfamoyl, and phenylsulfamoyl.

    [0062] Z1 and Z2 preferably is a 3,3-dialkylindolenine or 3,3-dialkylbenzoindolenine nucleus which may have one or more substituents. More preferably, each of Z1 and Z2 is a 3,3-dialkylindolenine or 3,3-dialkylbenzoindolenine nucleus which may have one or more substituents.

    [0063] Preferably, each of R1 and R2 is an alkyl group. Preferred alkyl group is a linear chain, branched chain, or cyclic alkyl having 1 to 18 carbon atoms, particularly 1 to 8 carbon atoms, which may have one or more substituents. The substituents may be those mentioned for the nitrogen atom-containing heterocyclic group. Preferred alkyl groups are unsubstituted alkyl groups, and alkyl groups having one or more substituents such as aryl, halogen, hydroxyl, alkoxy, acyloxy, carbonamido, sulfonamido, oxycarbonyl, carboxyl, and sulfo. Examples of the alkyl group include methyl, ethyl, propyl, butyl, isobutyl, 2-ethylhexyl, octyl, benzyl, 2-phenylethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-carboxyethyl, 3-carboxypropyl, 4-carboxybutyl, carboxymethyl, 2-methoxyethyl, 2-(2-methoxyethoxy)ethyl, 2-sulfoethyl, 3-sulfopropyl, 3-sulfobutyl, 3-sulfobutyl, 2-(3-sulfopropoxy)ethyl, 2-hydroxy-3-sulfopropyl, 3-sulfopropoxyethoxyethyl, 2-acetoxyethyl, carboxymethoxymethyl, and 2-methanesulfonylaminoethyl.

    [0064] The methine groups represented by L1 through L5 may have the same or are different from each other and each has a substituent. The substituents may be those mentioned for the nitrogen atom-containing heterocyclic group. The substituents may be combined to form a 5- to 7-membered ring, for instance, a ring of cyclopentene, 1-dimethylaminocyclopentene, 1-diphenylaminodcyclopentene, cyclohexene, 1-chlorocyclohexene, isophorone, 1-morpholinocyclopentene, or cycloheptene. Otherwise, the substituent may be combined with an auxochrome to form a ring.

    [0065] Each of n1 and n2 independently 0, 1 or 2, provided that n1+n2 is 3 or less.

    [0066] M1 is an electron-balancing counter ion, and may be a cation or an anion. Examples of the cations include alkali metal ions such as sodium ion, potassium ion, and lithium ion, and organic ions such as tetraalkylammonium ion and pyridinium ion. The anions may be an inorganic anion or an organic anion. Examples of the anions are as follows: halide anions (e.g., F-, Cl-, Br-, and I-), sulfonate ions (e.g., methanesulfonate ion, trifluoromethanesulfonate ion, p-toluenesulfonate ion, p-chlorobenzenesulfonate ion, benzene-1,3-disulfonate ion, naphthalene-1,5-disulfonate ion, and naphthalene-2,6-disulfonate ion), sulfate ion (e.g., methylsulfate ion), thiocyanate ion, perchlorate ion, tetrafluoroborate ion, picrate ion, acetate ion, metal complex ion having the following formula:

    (R is a halogen atom or an alkyl group; M5 is cobalt, nickel, or copper, and u is an integer of 0 to 4), and phosphate ion (e.g., hexafluorophosphate ion).

    [0067] The anion preferably is monovalent or divalent. A divalent anion is most preferred. m1 is a number of 0 or more, preferably a number of 0 to 4, which is required for balancing the electric charge. If an intra-molecular salt is formed, m1 is 0.

    [0068] The compound of the formula (II) may be present in the bis-form by combining two compounds at an optionally chosen carbon site.

    [0069] Representative examples of the preferred divalent anions include divalent sulfonate ions such as benzene-1,3-disulfonate ion, 3,3'-biphenyldisulfonate ion, naphthalene-1,5-disulfonate ion, naphthalene-1,6-disulfonate ion, naphthalene-2,6-disulfonate ion, 1-methylnaphthalne-2,6-disulfonate ion, naphthalene-2,7-disulfonate ion, naphthalene-2,8-disulfonate ion, 2-naphthol-6,8-disulfonate ion, 1,8-dihydroxynaphthalene-3,6-disulfonate ion, and 1,5-dihydroxynaphthalene-2,6-disulfonate ions. Most preferred are naphthalene-1,5-disulfonate ion, naphthalene-1,6-disulfonate ion, naphthalene-2,6-disulfonate ion, 1-methylnaphthalne-2,6-disulfonate ion, naphthalene-2,7-disulfonate ion, and naphthalene-2,8-disulfonate ion. Particularly preferred is naphthalene-1,5-disulfonate ion.

    [0070] The cyanine dyes of the formula (II) preferably have the following formula (II-1) or (II-2):





    [0071] In the formulas (II-1) and (II-2), each of Z3 and Z4 independently is an atomic group for forming a benzene or naphthalene ring which may have one or more substituents; each of R3, R4, R5, R6, R7 and R8 is independently an alkyl group having 1 to 8 carbon atoms; R9 is hydrogen, an alkyl group having 1 to 8 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, a heterocyclic ring, a halogen atom, or a carbamoyl group having 1 to 8 carbon atoms; M2m2- is an anion; and m2 is 1 or 2.

    [0072] With respect to the formulas (II-1) and (II-2), preferred combinations are described below.

    [0073] Each of Z3 and Z4 independently is an atomic group for forming a benzene or naphthalene ring having no substituent or a benzene ring having one or two substituents. Examples of the substituents include an alkoxy having 1 to 3 carbon atoms, a halogen atom, an alkoxy group having 1 to 3 carbon atoms, a sulfonamido group, and alkoxy group. If the benzene ring has two adjoining substituents, the adjoining substituents may be combined to form a ring (e.g., 1,3-dioxorane ring).

    [0074] Each of R3, R4 is an alkyl group having 1 to 6 carbon atoms, which may have a fluorine or alkoxy substituent.

    [0075] Each of R5, R6, R7 and R8 independently is an alkyl group having 1 to 6 carbon atoms which has no substituent.

    [0076] R9 is hydrogen, an alkyl group having 1 to 6 carbon atoms, phenyl, benzyl, pyridyl, pyrimidyl, benzoxazole, or halogen.

    [0077] M2 is a divalent sulfonate ion, a perchlorate ion, a hexafluorophosphate ion, or a metal complex ion having the following formula:

    (R is a halogen atom or an alkyl group; M5 is cobalt, nickel, or copper, and u is an integer of 0 to 4).

    [0078] With respect to the formulas (II-1) and (II-2), most preferred combinations are described below.

    [0079] Each of Z3 and Z4 independently is an atomic group for forming a benzene or naphthalene ring having no substituent or a benzene ring having one or two substituents. Examples of the substituents are methyl, chlorine, fluorine, methoxy, ethoxy, sulfonamido, and ethoxycarbonyl. If the benzene ring has two adjoining substituents, the adjoining substituents may be combined to form a ring (e.g., 1,3-dioxorane ring).

    [0080] Each of R3, R4 is an alkyl group having 1 to 6 carbon atoms, which have no substituent. Preferred is methyl, ethyl, propyl, isopropyl, or butyl. Each of R5, R6, R7 and R8 independently is methyl or ethyl. R9 is hydrogen, methyl, ethyl, chlorine, or bromine.

    [0081] M2 is a divalent sulfonate ion, a perchlorate ion, a hexafluorophosphate ion, or a metal complex ion having the aforementioned formula.

    [0082] The cyanine dye of the aforementioned formula (II-1) preferably has one of the following formulas (II-1-A, II-1-B, II-1-C), and the formula (II-1-B) is preferred:







    [0083] The cyanine dye of the aforementioned formula (II-2) preferably has one of the following formulas (II-2-A, II-2-B, II-2-C), and the formula (II-2-B) is preferred:







    [0084] In the formulas of (II-1-A), (II-1-B), (II-1-C), (II-2-A), (II-2-B), and (II-2-C), R10 has the same meaning as that of R3 or R4 for the formula (II-1) or (II-2); each of R11 and R12 has the same meaning as that of R5, R6, R7, or R8 for the formula (II-1) or (II-2). R13 has the same meaning as that of R9 for the formula (II-1) or (II-2). R14 is hydrogen, methyl, chlorine, fluorine, methoxy, ethoxy, sulfonamido, or ethoxycarbonyl. Each of M3 and m3 has the same meaning as that of M2 and m2, respectively, for the formula (II-1) or (II-2).

    [0085] Preferred cyanine dyes having the formula (II) are described below:





















    No.R1R2R3X-
    I-55 n-C4H9 CH3 OCH3 BF4-
    I-56 CH2CH2OCH3 CH3 H BF4-
    I-57 CH2CH2OCH3 CH2CH2OCH3 H ClO4-
    I-58 n-C4H9 CH2CH2OCH2CH2OCH3 H ClO4-
    I-59 n-C4H9 CH3 Cl BF4-
    I-60 n-C4H9 CH3 CH3 BF4-




































































































    [0086] The azo dyes are preferably represented by the following formula (III):



    [0087] In the formula (III), M is a metal atom; X is an oxygen atom, a sulfur atom, or =NR11 in which R11 represents hydrogen, an alkyl group, an aryl group, an acyl group, an alkylsulfonyl group or an arylsulfonyl group; Z11 is an atomic group for forming a 5- or 6-membered nitrogen-containing heterocyclic ring; and Z12 is an atomic group for forming an aromatic ring or a heterocyclic aromatic ring. Each ring may has one or more substituents.

    [0088] The azo dyes of the formula (III) preferably have the following formula (III-1):



    [0089] In the formula (III-1), M is iron, cobalt, nickel, copper, zinc, palladium, platinum or gold; Y is oxygen atom, sulfur atom or =NR12; each of R12, R13 and R14 independently is an alkyl group having 1 to 12 carbon atoms which may have one or more substituents; R13 and R14 may be combined to form a ring; R15 is an alkyl group having 1 to 12 carbon atoms which may have one or more substituents, a phenyl group having 6 to 16 carbon atoms which may have one or more substituents, or naphthyl group; each of R16 and R17 independently is hydrogen, a halogen atom, an alkyl group, an aryl group, cyano, an acyl group, an alkylsulfonyl group, or an arylsulfonyl group; and each of R18, R19 and R20 independently is hydrogen, an alkyl group, an aryl group, hydroxyl, an alkoxy group, an aryloxy group, amino, a carboxylic amide group, a sulfonamide group, cyano, a halogen atom, an acyl group, an alkylsulfonyl group, or an arylsulfonyl group.

    [0090] The azo dyes of the formula (III-1) preferably have the following formula (III-2):



    [0091] In the formula (III-2), M preferably is iron, cobalt, or nickel. Nickel is most preferred.

    [0092] R21 preferably is an alkylsulfonyl group having 1 to 4 carbon atoms or an arylsulfonyl group having 6 to 10 carbon atoms, which may have one or more substituents. Particularly preferred are an alkylsulfonyl group having 1 to 4 carbon atoms which has no substituent or has a fluorine atom substituent (e.g., methylsulfonyl or trifluoromethylsulfonyl) and an arylsulfonyl group having 6 to 10 carbon atoms, which has no substituent (e.g., phenylsulfonyl) .

    [0093] Each of R22, R23 and R24 preferably is an alkyl group having 1 to 4 carbon atoms which may have one or more substituents. Preferred substituents are halogen, hydroxyl, cyano, alkoxy, alkylthio, arylthio, acyl, alkylsulfonyl, and arylsulfonyl. More preferably, each of R22, R23 and R24 independently is an alkyl group having 1 to 4 carbon atoms which has no substituent. It is also preferred that R23 and R24 are combined to form a ring (e.g., pyrrolidine or morpholine).

    [0094] Each of R25 and R26 preferably is cyano, acyl, alkylsulfonyl, or arylsulfonyl. Most preferred is cyano for each of R25 and R26.

    [0095] Each of R27, R28 and R29 preferably is hydrogen, alkyl, aryl, hydroxyl, alkoxy, aryloxy, amino, carbonamio, or sulfonamido. Most preferred is hydrogen for each of R27, R28 and R29.

    [0096] Representative examples of the azo dyes of the formula (III) are described below.





    [0097] The oxonol dyes are preferably compounds represented by the following formula (IV-1) or (IV-2). The oxonol dyes of the formulas (IV-1) and (IV-2) are described in Japanese Patent Provisional Publication Nos. 10-297103, 10-309871, and 10-309872.





    [0098] In the formulas (IV-1) and (IV-2), each of A21, A22, B21 and B22 independently is a substituent group; each of Y21 and Z21 independently is an atomic group for forming a carbocyclic or heterocyclic ring; each of E and G independently is an atomic group for forming a conjugated double bond chain; X21 is =O, =NR21 or =C(CN) 2; X22 is -O, -NR21 or -C(CN)2 [in which R21 is a substituent group]; each of L21, L22, L23, L24 and L25 independently is a methine group which may be substituted; Vk+ is a cation; each of n3 and n4 independently is 0, 1 or 2; each of x and y independently is 0 or 1; and k is an integer of 1 to 10.

    [0099] Examples of the substituents groups represented by A21, A22, B21 and B22 include a linear (or straight) chain, branched chain, or cyclic alkyl group having 1 to 18 carbon atoms, particularly 1 to 8 carbon atoms, which may have one or more substituents; an alkenyl group having 2 to 18 carbon atoms, particularly 2 to 8 carbon atom; an aryl group having 6 to 18 carbon atoms, particularly 6 to 10 carbon atoms, which may have one or more substituents; an aralkyl group having 7 to 18 carbon atoms, particularly 7 to 12 carbon atoms, which may have one or more substituents; an acyl group having 2 to 18 carbon atoms, particularly 2 to 8 carbon atoms, which may have one or more substituents; an alkyl- or arylsulfonyl group having 1 to 18 carbon atoms, particularly 1 to 8 carbon atoms, which may have one or more substituents; an alkylsulfinyl group having 1 to 18 carbon atoms, particularly 1 to 8 carbon atoms, an alkoxycarbonyl group having 2 to 18 carbon atoms, particularly 2 to 8 carbon atoms, an aryloxycarbonyl having 7 to 18 carbon atoms, particularly 7 to 12 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, particularly 1 to 8 carbon atoms, which may have one or more substituents; an aryloxy group having 6 to 18 carbon atoms, particularly 6 to 10 carbon atoms, which may have one or more substituents; an alkylthio group having 1 to 18 carbon atoms, particularly 1 to 8 carbon atoms, an arylthio group having 6 to 18 carbon atoms, particularly 6 to 10 carbon atoms; an acyloxy group having 2 to 18 carbon atoms, particularly 2 to 8 carbon atoms, which may have one or more substituents; a sulfonyloxy group having 1 to 18 carbon atoms, particularly 1 to 8 carbon atoms, which may have one or more substituents; a carbamoyloxy group having 1 to 18 carbon atoms, particularly 1 to 8 carbon atoms, which may have one or more substituents; an unsubstituted amino group; an amino group having a substituent which has 1 to 18 carbon atoms, particularly 1 to 8 carbon atoms; an unsubstituted carbamoyl group; a carbamoyl group having a substituent which has 1 to 18 carbon atoms, particularly 1 to 8 carbon atoms; an unsubstituted sulfamoyl group; a sulfamoyl group having a substituent which has 1 to 18 carbon atoms, particularly 1 to 8 carbon atoms; a halogen atom, and a heterocyclic group. These substituents may have one or more substituents.

    [0100] Each of [-C(=L21) - (E)x-C(=X21)-] (referred to as W1) combined with Y21 and [-C(=L25)-(G)y-C(-X22)-] (referred to as W2) combined with Z21 is under conjugated condition. Therefore, a carbon ring or a heterocyclic ring formed by Y21 and W1 as well as Z21 and W2 is in a resonance structure. The carbon ring or heterocyclic ring preferably is one of 4- to 7-membered rings, preferably 5- to 6-membered rings. These rings may be fused with other 4-to 7-membered rings to form a condensed ring. These rings may have one or more substituents such as those hereinbefore described for A21, A22, B21 and B22.

    [0101] It is preferred that each of x and y is 0. It is also preferred that X21 is =O and X22 is -O.

    [0102] The oxonol dyes are preferably represented by the following formula (IV-2-A):



    [0103] In the formula, each of R51, R52, R53 and R54 independently is hydrogen, an alkyl group, an aryl group, an aralkyl group, or heterocyclic group. These group may have one or more substituents. Each of L31, L32, and L33 independently is a methine group which may have a substituent. n5 is 0, 1, 2, or 3. If n5 is 2 or 3, each of the plural L32 and L33 may be the same or different. Vk+ is a cation. k is an integer of 1 to 10.

    [0104] The anionic component (namely, anion part) is described below.

    [0105] The alkyl group for R51, R52, R53 and R54 preferably is an alkyl group having 1 to 20 carbon atoms, which may have one or more substituents, such as methyl, ethyl, propyl, butyl, isobutyl, t-butyl, isoamyl, cyclopropyl, or cyclohexyl.

    [0106] Examples of the above-mentioned substituents include an alkyl group having 1 to 20 carbon atoms (e.g., methyl, ethyl, propyl, carboxymethyl, or ethoxycarbonyl); an aralkyl group having 7 to 20 carbon atoms (e.g., benzyl or phenethyl); an alkoxy group having 1 to 8 carbon atoms (e.g., methoxy or ethoxy); an aryl group having 6 to 20 carbon atoms (e.g., phenyl or naphthyl); an aryloxy group having 6 to 20 carbon atoms (e.g., phenoxy or naphthoxy); a heterocyclic group (e.g., pyridyl, pyrimidyl, pyridazyl, benzoimidazolyl, benzothiazolyl, benzoxazolyl, 2-pyrrolidin-1-yl, 2-piperidon-1-yl, 2,4-dioxyimidazolidin-3-yl, 2,4-dioxyoxazolidin-3-yl, succinimido, phthalimido, or maleimido); a halogen atom (e.g., fluorine, chlorine, bromine, or iodine); a carboxyl group; an alkoxycarbonyl group having 2 to 10 carbon atoms (e.g., methoxycarbonyl or ethoxycarbonyl); a cyano group; an acyl group having 2 to 10 carbon atoms (e.g., acetyl or pivaloyl); a carbamoyl group having 1 to 10 carbon atoms (e.g., carbamoyl, methyl carbamoyl, or morpholinocarbamoyl); an amino group; an amino group having a substituent which has 1 to 20 carbon atoms (e.g., dimethylamino, diethylamino, bis(methylsulfonylethyl)amino, or N-ethyl-N'-sulfoethylamino); a sulfo group; a hydroxyl group; a nitro group; a sulfonamido group having 1 to 10 carbon atoms (e.g., methanesulfonamido); a ureido group having 1 to 10 carbon atoms (e.g., ureido or methylureido); a sulfonyl group having 1 to 10 carbon atoms (e.g., methanesulfonyl or ethanesulfonyl); a sulfinyl group having 1 to 10 carbon atoms (e.g., methanesulfinyl); and a sulfamoyl group having 0 to 10 carbon atoms (e.g., sulfamoyl or methanesulfamoyl). The carboxyl group and sulfo group may be in the form of a salt.

    [0107] The aryl group for R51, R52, R53 and R54 can be an aryl group having 6 to 20 carbon atoms (e.g., phenyl or naphthyl). The aryl group may have one or more substituents such as those described above.

    [0108] The aralkyl group for R51, R52, R53 and R54 can be an aralkyl group having 7 to 20 carbon atoms (e.g., benzyl or phenethyl). The aralkyl group may have one or more substituents such as those described above.

    [0109] The heterocyclic group for R51, R52, R53 and R54 can be a 5- or 6-membered saturated or unsaturated heterocyclic group which comprises one or more of carbon atoms, nitrogen atoms, oxygen atoms, and/or sulfur atoms. Examples include pyridyl, pyrimidyl, pyridazyl, piperidyl, triazyl, pyrrolyl, imidzolyl, triazolyl, furanyl, thiophenyl, thiazolyl, oxazolyl, isothiazolyl, and isoxazolyl. These heterocyclic group may be fused with a benzene ring to form a condensed ring, such as, quinolyl, benzoimidazolyl, benzothiazolyl, or benzoxazolyl. The heterocyclic group may have one or more substituents such as those described above.

    [0110] Each of R51, R52, R53 and R54 preferably is an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, or a heterocyclic group having 6 to 10 carbon atoms.

    [0111] If each of R51, R52, R53 and R54 is an alkyl group, R51 and R52 or R53 and R54 can be combined to form a carbon ring (e.g., cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, 2-methylcyclohexyl, cycloheptyl, or cycloctyl) or a heterocyclic ring (e.g., piperidyl, curomanyl, or morpholyl). R51 and R52 or R53 and R54 are preferably combined to form a carbon ring having 3 to 10 carbon atoms or a heterocyclic group having 2 to 10 carbon atoms.

    [0112] Each of L31, L32 and L33 independently is a substituted or unsubstituted methine group. Examples of the substituents can be those described hereinbefore. Each of L31, L32 and L33 preferably is an unsubstituted methine group, or a methine group having a substituent such as an alkyl group having 1 to 5 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a saturated or unsaturated heterocyclic group, or a halogen atom. n5 preferably is 1, 2 or 3.

    [0113] Preferred anion parts of the oxonol dyes having the formula (IV-1) or (IV-2), particularly (IV-2-A), are illustrated below.

















































    [0114] The cationic component (namely, cation part) is described below.

    [0115] Examples of the cation parts represented by Vk+ include hydrogen ion, metal ions such as sodium ion, potassium ion, lithium ion, calcium ion, iron ion, and copper ion, ammonium ions, pyridinium ion, oxonium ions, sulfonium ions, phosphonium ions selenonium ion, and iodonium ion. Vk+ preferably is not a cyanine ion. Preferred is a quaternary ammonium ion.

    [0116] The quaternary ammonium ion can be prepared by alkylation (Menshutkin reaction), alkenylation, alkynylation or arylation of a tertiary amine (e.g., trimethylamine, triethylamine, tributylamine, triethanolamine, N-methylpyrrolidine, N-methylpiperidine, N,N-dimethylpiperazine, triethylenediamine, or N,N,N',N'-tetramethylethylenediamine) or a compound having a nitrogen atom-containing heterocyclic ring such as a pyridine, picoline, 2,2'-bipyridyl, 4,4'-bipyridyl, 1,10-phenanthroline, quinoline, oxazole, thiazole, N-methylimidazole, pyrazine, or tetrazole).

    [0117] The quaternary ammonium ion preferably has a nitrogen-containing heterocyclic group. Most preferred is a quaternary pyridinium ion.

    [0118] k is an integer of 1 to 10, preferably 1 to 4. Most preferred is 2.

    [0119] The quaternary ammonium ion preferably has the below-mentioned formula (V-1). This compound can be easily prepared by the Menshutkin reaction (see, for instance, Japanese Patent Provisional Publication No. 61-148162) or arylation (see, for instance, Japanese Patent Provisional Publications No. 51-16675 and No. 1-96171) of 2,2'-bipyridyl or 4,4'-bipyridyl with a halide having the desired substituent.



    [0120] In the formula (V-1), each of R60 and R61 independently is a substituent, and each of R62 and R63 is alkyl, alkenyl, alkynyl, aralkyl, aryl, or a heterocyclic group. Each combination of R60 and R61, R60 and R62, and R61 and R63 may be combined with each other to form a ring. Each of r and s independently is an integer of 0 to 4. If any of r and s is 2 or more, plural numbers of R60 and R61 may be the same or different.

    [0121] The alkyl group for R62 and R63 preferably is a straight chain, branched chain, or cyclic alkyl group having 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, which may have one or more substituents. Examples are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, neopentyl, n-hexyl, cyclopropyl, cyclohexyl, or adamantyl.

    [0122] Examples of the substituents for the alkyl group are as follows (the following group may have one or more substituent groups including an alkenyl group having 2 to 18 carbon atoms, preferably 2 to 8 carbon atoms (e.g., vinyl); an alkynyl group having 2 to 18 carbon atoms, preferably 2 to 8 carbon atoms (e.g., ethynyl); an aryl group having 6 to 10 carbon atoms (e.g., phenyl and naphthyl); a halogen atom (e.g., F, Cl, or Br);an alkoxy group having 1 to 18 carbon atoms, preferably 1 to 8 carbon atoms (e.g., methoxy or ethoxy); an aryloxy group having 6 to 10 carbon atoms (e.g., phenoxy or p-methoxyphenoxy); an alkylthio group having 1 to 18 carbon atoms, preferably 1 to 8 carbon atoms (e.g., methylthio or ethylthio); an arylthio group having 6 to 10 carbon atoms (e.g, phenylthio); an acyl group having 2 to 18 carbon atoms, preferably 2 to 8 carbon atoms (e.g., acetyl or propionyl); an alkylsulfonyl group having 1 to 18 carbon atoms, preferably 1 to 8 carbon atoms (e.g., methanesulfonyl or p-toluenesulfonyl); an acyloxy group having 2 to 18 carbon atoms, preferably 2 to 8 carbon atoms (e.g., acetoxy or propionyloxy); an alkoxycarbonyl having 2 to 18 carbon atoms, preferably 2 to 8 carbon atoms (e.g., methoxycarbonyl or ethoxycarbonyl); an arylcarbonyl group having 7 to 11 carbon atoms (e.g., naphthoxycarbonyl); an amino group; a substituted amino group (e.g., methylamino, dimethylamino, diethylamino, anilino, methoxyphenylamino, chlorophenylamino, pyridylamino, methoxycarbonylamino, n-butoxycarbonylamino, phenoxycarbonylamino, methylcarbamoylamino, ethylthiocarbamoylamino, phenylcarbamoylamino, acetylamino, ethylcarbonylamino, ethylthiocarbamoylamino, cyclohexylcarbonylamino, benzoylamino, chloroacetylamino, or methylsulfonylamino); a carbamoyl group having 1 to 18 carbon atoms, preferably 1 to 8 carbon atoms (e.g., unsubstituted carbamoyl, methylcarbamoyl, ethylcarbamoyl, n-butylcarbamoyl, t-butylcarbamoyl, dimethylcarbamoyl, morpholinocarbamoyl, or pyrrolidinocarbamoyl); unsubstituted sulfamoyl group; a substituted carbamoyl group having 1 to 18 carbon atoms, preferably 1 to 8 carbon atoms (e.g., methylsulfamoyl, or phenylsulfamoyl); a cyano group; a nitoro group; a carboxy group, a hydroxyl group; a heterocyclic group (e.g., oxazole ring, benzoxazole ring, thiazol ring, benzothiazol ring, imidazole ring, benzoimidazole ring, indolenine ring, pyridine ring, piperidine ring, pyrrolidine ring, morpholine ring, sulforane ring, furan ring, thiophene ring, pyrazole ring, pyrrole ring, cumarone ring, or cumarin ring.

    [0123] The alkenyl group for R62 and R63 preferably is an alkenyl group having 2 to 18 carbon atoms, preferably 2 to 8 carbon atoms, which may have one or more substituents, such as vinyl, allyl, 1-propenyl, or 1,3-butandienyl. The substituents for the alkenyl group can be the same as those described hereinbefore for the alkyl group.

    [0124] The alkynyl group for R62 and R63 preferably is an alkynyl group having 2 to 18 carbon atoms, preferably 2 to 8 carbon atoms, which may have one or more substituents, such as ethynyl or 2-propynyl. The substituents for the alkynyl group can be the same as those described hereinbefore for the alkyl group.

    [0125] The aralkyl group for R62 and R63 preferably is an aralkyl group having 7 to 18 carbon atoms, which may have one or more substituents, such as benzyl or methylbenzyl.

    [0126] The aryl group for R62 and R63 preferably is an aryl group having 6 to 18 carbon atoms, which may have one or more substituents, such as phenyl or naphthyl. The substituents for the aryl group can be the same as those described hereinbefore for the alkyl group. Otherwise, the substituent may be an alkyl group such as methyl or ethyl.

    [0127] The heterocyclic group for R62 and R63 preferably has a 5- or 6-membered saturated or unsaturated heterocyclic ring comprising carbon, nitrogen, oxygen and/or sulfur atom(s), such as oxazole ring, benzoxazole ring, thiazol ring, benzothiazol ring, imidazole ring, benzoimidazole ring, indolenine ring, pyridine ring, piperidine ring, pyrrolidine ring, morpholine ring, sulforane ring, furan ring, thiophene ring, pyrazole ring, pyrrole ring, cumarone ring, or cumarin ring. The heterocyclic ring may have one or more substituents. The substituents for the heterocyclic ring group can be the same as those described hereinbefore for the alkyl group.

    [0128] The substituents for R60 and R61 can be the same as those described hereinbefore for the alkyl group. Otherwise, the substituent can be an alkyl group such as methyl or ethyl. The substituent for R60 and R61 preferably is hydrogen or an alkyl group. Hydrogen is most preferred.

    [0129] The quaternary ammonium ion preferably has the following formula (V-1-A) or (V-1-B):



    [0130] In the formula, R64 and R65 can be the same as the substituents described for R60 and R61 of the formula (V-1). R66 and R67 can be the same as the substituents described for R62 and R63 of the formula (V-1). Each of r and s is an integer of 0 to 4. If r or s is 2 or more, plural numbers of R64 or R65 can be the same or different;



    [0131] In the formula, R68 and R69 can be the same as the substituents described for R60 and R61 of the formula (V-1). R68 and R69 preferably are combined with each other to form a carbon ring or a heterocyclic ring, particularly, a condensed ring in combination with the pyridine rings to which R68 and R69 are attached. Each of r and s is an integer of 0 to 4. If r or s is 2 or more, plural numbers of R68 or R69 can be the same or different.

    [0132] Representative examples of the cation parts of the oxonol dyes having the formula (IV-1) or (IV-2), including the formula (IV-2-A) are illustrated below:

            B-1    N(CH3)4

            B-2    N(C2H5)4

            B-3    N(C4H9(n))4

























































































































































    [0133] Representative examples of the oxonol dyes having the formula (IV-1) or (IV-2), including the formula (IV-2-A) are illustrated in the following Tables 1(1) and 1(2), in which the dye compound (identified by the dye number) is expressed by the combination of an anion part (A- ) and a cation part (B- ). For instance, the dye compound of the dye number 1 which is formed of the anion part of A-4 and the cation part of B-21 has the following formula:

    Table 1(1)
    Dye No.AnionCationDye No.AnionCation
    1 A-4 B-21 2 A-4 B-77
    3 A-4 B-123 4 A-5 B-21
    5 A-5 B-78 6 A-6 B-22
    7 A-7 B-22 8 A-10 B-78
    9 A-10 B-117 10 A-5 B-123
    11 A-11 B-85 12 A-14 B-21
    13 A-14 B-77 14 A-14 B-113
    15 A-15 B-1 16 A-15 B-148
    17 A-15 B-168 18 A-21 B-15
    19 A-21 B-103 20 A-23 B-74
    21 A-24 B-78 22 A-25 B-78
    23 A-28 B-78 24 A-33 B-30
    25 A-33 B-51 26 A-34 B-78
    27 A-36 B-21 28 A-36 B-78
    29 A-36 B-87 30 A-37 B-21
    31 A-37 B-41 32 A-37 B-78
    33 A-37 B-113 34 A-37 B-117
    35 A-38 B-117 36 A-38 B-133
    37 A-38 B-85 38 A-39 B-23
    39 A-39 B-33 40 A-39 B-55
    41 A-39 B-78 42 A-39 B-85
    43 A-39 B-117 44 A-39 B-123
    45 A-39 B-168 46 A-40. B-21
    47 A-40 B-55 48 A-40 B-78
    49 A-40 B-85 50 A-40 B-89
    51 A-40 B-113 52 A-40 B-117
    53 A-40 B-168 54 A-41 B-21
    55 A-44 B-33 56 A-44 B-50
    57 A-44 B-78 58 A-44 B-94
    59 A-44 B-98 60 A-44 B-117
    61 A-44 B-132 62 A-45 B-21
    63 A-45 B-53 64 A-48 B-24
    65 A-48 B-33 66 A-48 B-55
    67 A-48 B-84 68 A-48 B-110
    69 A-48 B-117 70 A-49 B-78
    71 A-49 B-94 72 A-49 B-115
    73 A-49 B-117 74 A-50 B-78
    75 A-55 B-18 76 A-55 B-82
    77 A-55 B-114 78 A-57 B-78
    79 A-58 B-78 80 A-60 B-33
    81 A-60 B-78 82 A-60 B-117
    83 A-61 B-17 84 A-61 B-79
    85 A-64 B-27 86 A-64 B-77
    87 A-69 B-78 88 A-69 B-117
    89 A-70 B-26 90 A-70 B-76
    91 A-72 B-77 92 A-73 B-77
    93 A-73 B-94 94 A-74 B-24
    95 A-74 B-78 96 A-82 B-78
    97 A-93 B-21 98 A-93 B-78
    99 A-94 B-78 100 A-96 B-78
    101 A-5 B-24      


    [0134] The oxonol dyes of the formula (IV-1) or (IV-2) can be prepared by the preparation process described in Japanese Patent Provisional Publication 10-297103.

    [0135] According to the present invention, the dye is dissolved in a solvent comprising the fluorinated cyclic alkane 1,1,2,2,3,3,4-heptafluorocyclopentane, so as to form a dye solution for the preparation of the recording dye layer.

    [0136] The fluorinated cyclic alkane is a 5-membered fluorinated cyclic alkane.

    [0137] The solvent may consist essentially of the claimed fluorinated cyclic alkane. Most of the laser light-sensitive dyes described in detail hereinbefore can be soluble in the fluorinated cyclic alkane. However, the solubility is not high, and the dissolving rate is not high. Therefore, if the fluorinated cyclic alkane is employed alone as the solvent for a laser light-sensitive dye, the dye solution is preferably prepared by the steps of mixing the organic dye and the solvent and keeping the resulting mixture at a temperature of higher than 45°C but lower than a boiling temperature of the solvent by at least 10°C for a period of 5 minutes to 2 hours.

    [0138] The dye-dissolving steps of the above-mentioned procedure is further described.

    [0139] In the first step, a laser light-sensitive dye is added to a solvent containing the fluorinated cyclic alkane so as to prepare a dye-solvent mixture. The mixture of the dye and solvent is preferably prepared by adding the dye in the solvent at room temperature (25°C).

    [0140] In the second step, the mixture is kept at a temperature of not lower than 45°C and below the boiling point of the solvent by 5°C or more for 5 minutes to 2 hours so as to prepare a dye solution. The mixture is preferably kept at a temperature of not lower than 50°C (more preferably not lower than 55°C, further preferably not lower than 60°C) and below the boiling point of the solvent by 10°C or more (more preferably by 15°C or more, further preferably by 20°C or more). If the temperature is too high, the dye may deteriorate and the solvent often evaporates too much. The temperature is preferably kept in the aforementioned range for 10 to 90 minutes, more preferably 15 to 75 minutes. During this period, the dye is dissolved in the solvent enough to prepare a dye solution appropriately employable for the coating.

    [0141] In order to promote dissolution of the dye in the solvent, it is preferred that stirring or vibration should be applied to the mixture with a proper means while the mixture is kept at a temperature in the aforementioned range. Examples of the means for stirring or vibration include a means for ultrasonic wave and a magnetic stirrer. Preferred is a means for ultrasonic wave. The dye solution is preferably prepared in a container having a lid to efficiently keep the solvent from evaporation. A container equipped with a high pressure proof lid (e.g., a pressure container) is advantageously used. However, it is generally dangerous and difficult to use a pressure container. In consideration of this, a container having a lid provided with a hole for releasing vapor is preferably used. In this case, for reducing the amount of released vapor, an upright container is preferably used so that the surface of the dye/solvent mixture in the container may be small. A preferred example of that container is a container whose upper part has a small cross section. When the dye/solvent mixture is heated to a high temperature, the dye is liable to deteriorate. Since the dye is further liable to deteriorate in the presence of oxygen, the air in contact with the mixture may be made to contain oxygen in as small an amount as possible. The amount of oxygen preferably is less than 15%, more preferably less than 10%, further preferably less than 5%, most preferably less than 1%.

    [0142] The dye solution is preferably adjusted to have a concentration in a specific range because the concentration affects the coating properties. For example, during the preparation of the dye solution, the amount of evaporated solvent is measured, and according to that the solvent is additionally supplemented. The solvent is preferably supplemented in several portions, and the portions are preferably added at a specific temperature. Preferably, they are supplemented approx. at room temperature (20 to 30°C, more preferably 22 to 28°C). If the amount of evaporated solvent is too much, the dye solution is so concentrated that insoluble nuclei of the dye may be produced. The amount of evaporated solvent, therefore, is preferably controlled to be not more than 30%, more preferably not more than 20%, further preferably not more than 10% based on the initial volume.

    [0143] The fluorinated cyclic alkane 1,1,2,2,3,3,4-heptafluorocyclopentane is advantageously employed in a combination with an organic liquid which has a boiling point higher than that of the fluorinated cyclic alkane, which is essentially inert to the substrate, and in which the dye is soluble, in a volume ratio of 99:1 to 51:49 (alkane :organic liquid). The range of volume ratio preferably is 95:5 to 70:30, more preferably 90:10 to 80:20. The organic liquid preferably has a boiling point of lower than 250°C (preferably lower than 200°C, more preferably lower than 180°C) but higher than that of the fluorinated cyclic alkane by at least 10°C (preferably at least 15°C, more preferably at least 20°C).

    [0144] Examples of such high-boiling point solvents include aliphatic ketone, an aliphatic hydrocarbon, an alicyclic hydrocarbon, a carboxylic acid ester, an aliphatic ether, and an alcohol. The alcohol preferably is aliphatic alcohol, alicyclic alcohol, aromatic alcohol, fluorinated alcohol, alkoxyalcohol, or ketoalcohol. The high-boiling solvents can be employed singly or in combination.

    [0145] Examples of the high-boiling point solvents are described below: an aliphatic ketone having 4 to 12 carbon atoms (e.g., t-butylmethylketone and disobutylketone); an aliphatic hydrocarbon having 5 to 10 carbon atoms (e.g., hexane, heptane, octane, nanane, and decane); an alicyclic hydrocarbon having 6 to 12 carbon atoms (e.g., cyclohexane, methylcyclohexane, dimethylcyclohexane, ethylcyclohexane, isopropylcyclohexane, t-butylcyclohexane, and cyclooctane); a carboxylic acid ester having 5 to 10 carbon atoms (e.g., isopropyl acetate, t-butyl acetate, isobutyl propionate, t-butyl propionate, ethyl pivalate, methyl lactate, ethyl lactate, isopropyl isovalate, and isobutyl isovalate); an aliphatic ether having 6 to 10 carbon atoms (e.g., diisopropyl ether and diisobutyl ether); a saturated aliphatic alcohol having 1 to 12 carbon atoms (e.g., methyl alcohol, ethyl alcohol, n-propylalcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, sec-butyl alcohol, t-butyl alcohol, 3-methyl-2-butanol, 2-ethylbutanol, 2-methyl-1-butanol, pentanol, t-pentyl alcohol, 3-methyl-1-pentyl-3-ol, 4-methyl-2-pentanol, 2,4-pentanediol, n-hexanol, 2-ethylhexanol, n-heptanol, 2-heptanol, 3-heptanol, n-octanol, and 2-octanol); an unsaturated aliphatic alcohol having 3 to 6 carbon atoms (e.g., allyl alcohol, propargyl alcohol, and 3-methyl-1-butyn-3-ol); an alicyclic alcohol having 5 to 8 carbon atoms (e.g., cyclopentanol, cyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, and 4-methylcyclohexanol); an aromatic alcohol having 7 to 10 carbon atoms (e.g., benzyl alcohol); a ketoalcohol having 3 to 8 carbon atoms (e.g., diacetone alcohol, 1-hydroxy-2-propanone, and 3-hydroxy-3-methyl-2-butanone); a monovalent or divalent fluorinated alcohol having 1 to 12 carbon atoms (e.g., 2,2-difluoro-1-ethanol, 2,2,2-trifluoro-1-ethanol, 1,3-difluoro-2-propanol, 2,2,3,3-tetrafluoro-1-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,4,4,4-hexafluoro-1-butanol, 2,2,3,3,4,4,5,5-octafluoro-1-pentanol, 3,3-difluoro-1,2-heptanediol, 4-(trifluoromethyl)benzyl alcohol, and 2,6-difluoro-α-methylbenzyl alcohol); an alkoxyalcohol having 3 to 12 carbon atoms (e.g., ethylene glycol monomethyl ether (methylcellosolve and methoxyethanol), ethylene glycol monoethyl ether (ethylcellosolve and ethoxyethanol), ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether (butylcellosolve), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, ethylene glycol diglycidyl ether, ethylene glycol dimethyl ether, 1-ethoxy-2-propanol, 1-methoxy-2-propanol, 2-isopropoxy-1-ethanol, 1-methoxy-2-butanol, 3-methoxy-1-butanol, 4-methoxy-1-butanol, and 2-(2-methoxyethoxy)ethanol.

    [0146] Preferred high-boiling point solvents are aliphatic ketones (e.g., t-butyl methyl ketone and di-isobutyl ketone), aliphatic hydrocarbons (e.g., heptane, octane, and nonane), saturated aliphatic alcohols (e.g., n-propyl alcohol, butyl alcohol, isobutyl alcohol, sec-butyl alcohol, 3-methyl-2-butanol, 2-ethylbutanol, 2-methyl-1-butanol, pentanol, 3-methyl-1-pentyl-3-ol, 4-methyl-2-pentanol), saturated aliphatic alcohols (e.g., propargyl alcohol and 3-methyl-1-butyn-3-ol), ketoalcohols (e.g., diacetone alcohol), fluorinated alcohols (e.g., 2,2,3,3-tetrafluoro-1-propanol, 2,2,3,3,4,4,5,5-octafluoro-1-pentanol; and alkoxyalcohols (e.g., ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol diglycidyl ether, and ethylene glycol diethyl ether).

    [0147] Most preferred are fluorinated alcohols (e.g., 2,2,3,3-tetrafluoro-1-propanol) and ketoalcohols (e.g., acetone alcohol).

    [0148] The fluorinated cyclic alkane 1,1,2,2,3,3,4-heptafluorocyclopentane is also employable for dissolving the laser-light sensitive dye in combination with an organic liquid which has a solubility for the dye higher than that of the fluorinated cyclic alkane and which is active to the substrate, in a volume ratio of 99.9:0.1 to 80:20 (preferably 99.7:0.3 to 88: 12, more preferably 99.5:0.5 to 92:8). The organic liquid preferably is a halogenated aliphatic hydrocarbon, an aromatic hydrocarbon, a ketone, a sulfoxide, an amide, a carboxylic acid ester, an ether, or a nitrile. The organic liquids can be employed singly or in combination.

    [0149] The organic liquid which is employable in a small amount in combination with the fluorinated cyclic alkane is further described below in more detail.

    [0150] The halogenated aliphatic hydrocarbon preferably has 1 to 6 carbon atoms. The halogen atom may be chlorine atom and bromine atom. Examples of the halogenated aliphatic hydrocarbons include dichloromethane, dichloroethane, trichloroethane, tetrachloroethane, 1,2,3-trichloropropane, 1,2-dibromopropane, 1-bromo-3-chloropropane, and 1,4-dichlorobutane.

    [0151] The aromatic hydrocarbon preferably has a benzene nucleus and has 6 to 10 carbon atoms. Examples of the aromatic hydrocarbons include bromobenzene, dichlorobenzene, 1-bromo-4-fluorobenzene, toluene, 2-chloro-6-fluorotoluene, o-xylene, m-xylene, and 1,2,4-trimethylbenzene.

    [0152] The ketone preferably has 2 to 10 carbon atoms and man be in the cyclic form. Examples of the ketones include acetone, 2,4-pentanedione, 3-heptanone, 4-heptanone, 2,6-dimethyl-4-heptanone, diisopropyl ketone, 2-methylbutyl ethyl ketone, cyclohexanone, 2-methylcyclohexanone, 3-methylcyclohexanone, and 4-methylcyclohexanone.

    [0153] The sulfoxide preferably has 2 to 10 carbon atoms, and preferably is dimethylsulfoxide.

    [0154] The amide preferably has 1 to 10 carbon atoms, and may be in the cyclic form. Examples of the amides include N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylformamide, N,N-dimethylpropionamide, and 1-methyl-2-pyrrolidone.

    [0155] The carboxylic acid ester preferably has 3 to 10 carbon atoms. Examples of the carboxylic acid esters include methyl acetate, ethyl acetate, ethyl trichloroacetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, t-butyl acetate, amyl acetate, ethyl 3-chloropropionate, n-propyl propionate, n-butyl propionate, n-propyl butyrate, methyl isobutyrate, ethyl isobutyrate, n-propyl isobutyrate, methyl pivalate, ethyl glycolate, ethyl pyruvate, and t-butyl acetacetate.

    [0156] The ether preferably has 2 to 10 carbon atoms, and may be in the cyclic form. Examples of the ethers include t-butoxy-2-ethoxy ether, butyl ether, propylene glycol methyl ether acetate, dioxane, anisole, 2,5-dimethoxy-2,5-dihydrofuran, 2,5-dimethoxytetrahydrofuran, 2-(bromomethyl)-tetrahydro-2H-pyrane, and 2-chloromethyl-1,3-dioxorane. Dioxane is preferred.

    [0157] The nitrile preferably has 1 to 6 carbon atoms. Examples of the nitriles include 3-bromopropionitrile, 3-ethoxypropylnitrile, and dimethylcarbamate nitrile (dimethylcyanamide).

    [0158] Examples of the preferred organic liquids include aliphatic halogenated hydrocarbons (particularly, dichloromethane, dichloroethane, and tetrachloroethane), aromatic hydrocarbons (particularly, toluene, o-xylene, and m-xylene), ketones (particularly, acetone and cyclohexanone), carboxylic acid esters (particularly, methyl acetate, ethyl acetate, and butyl acetate), and ethers (particularly dioxane).

    [0159] The fluorinated cyclic alkane 1,1,2,2,3,3,4-heptafluorocyclopentane can be employed in combination with a fluorinated alcohol in a volume ratio of 50:50 to 1:99. In this case, the fluorinated cyclic alkane serves not only to dissolve the laser light-sensitive dye but also to accelerate evaporation of the fluorinated alcohol, so as to shorten the period for drying the coated dye solution. Examples of the fluorinated alcohols are those mentioned hereinbefore.

    [0160] In the case that the fluorinated cyclic alkane is employed in combination with other solvents for the preparation of the dye solution, it is preferred that the dye solution is prepared by beforehand adding the dye to the fluorinated cyclic alkane to prepare a mixture, heating the mixture to dissolve the dye, and then adding other solvents to the mixture. Otherwise, the dye solution can be prepared by beforehand mixing the fluorinated cyclic alkane and other solvents to prepare a mixed solvent, adding the dye to the mixed solvent, and heating the mixture to dissolve the dye.

    [0161] The dye solution may further contain auxiliary additives such as oxidation inhibitors, UV absorbers, plasticizers, and lubricants.

    [0162] In the preparation of the dye solution, an anti-fading agent and, if needed, a binder can be incorporated. Examples of the anti-fading agents include nitroso compounds, metal complexes, diimmmonium salts and aminium salts. These examples are described, for example, in Japanese Patent Provisional Publications No. 2-300288, No. 3-224793 and No. 4-146189. If the anti-fading agent is used, its amount is in the range of usually 0.1 to 50 wt.%, preferably 0.5 to 45 wt.%, further preferably 3 to 40 wt.%, particularly preferably 5 to 25 wt.% base on the amount of the dye.

    [0163] Examples of the binders include natural-origin polymers such as gelatin, cellulose derivatives, dextran, rosin and rubber; hydrocarbon polymer resins such as polyethylene, polypropylene, polystyrene and polyisobutyrene; vinyl polymers such as polyvinyl chloride, polyvinylidene chloride and vinyl chloride-vinyl acetate copolymer; acrylate polymers such as polymethyl acrylate and polymethyl methacrylate; polyvinyl alcohol; chlorinated polyethylene; epoxy resins; butyral resins; rubber derivatives; and thermosetting resins such as prepolymers of phenol-formaldehyde. The binder is optionally employed so that the amount of the binder may be not more than 20 weight parts, preferably not more than 10 weight parts, further preferably not more than 5 weight parts based on 100 weight parts of the dye.

    [0164] The thus-prepared coating liquid contains the dye in a concentration of generally 0.01 to 10 wt.%, preferably 0.1 to 5 wt.%.

    [0165] The dye solution is then coated on the substrate disc.

    [0166] The dye solution is coated on the substrate disc, while the temperature of the liquid preferably is not higher than 40°C, more preferably not higher than 35°C, further preferably 25 to 30°C. The coating can be performed by the known methods such as spray coat, spin coat, dip coat, roll coat, blade coat, doctor roller coat and screen print. Spin coat is preferred. The recording dye layer can be a single layer or can comprise plural layers. The thickness of the recording dye layer (after drying) generally is in the range of 20 to 500 nm, preferably 50 to 300 nm.

    [0167] On the recording dye layer, the light-reflecting layer is generally placed so as to enhance the light-reflection in the course of reproduction of the recorded information. The light-reflecting material to be used for the formation of the light-reflecting layer should show a high reflection to the laser light. Examples of the light-reflecting materials include metals and submetals such as Mg, Se, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Si, Ge, Te, Pb, Po, Sn and Bi. Stainless steel film is also employable. These materials can be employed singly, in combination or in the form of alloy.

    [0168] Preferred are Cr, Ni, Pt, Cu, Ag, Au, Al and stainless steel. Au metal, Ag metal, and their alloys are particularly preferred. Preferred alloys of Au or Ag are alloys with at least one metal selected from the group consisting of Pt, Cu and Al. Most preferred is Ag metal or an alloy of Ag. The light-reflecting layer can be formed on the recording dye layer, for example, by vacuum deposition, sputtering or ion-plating. The thickness of the light-reflecting layer generally is 10 to 800 nm, preferably 20 to 500 nm, further preferably 50 to 300 nm.

    [0169] On the light-reflecting layer, a protective layer is generally provided so as to protect the recording dye layer and the light-reflecting layer from chemical deterioration or physical damage. The protective layer can be made of inorganic materials such as SiO, SiO2, MgF2, SnO2, Si3N4; or organic materials such as thermo-plastic resins, thermo-setting resins and UV curable resins. On the light-reflecting layer and/or the substrate, the protective layer can be formed by laminating a film of plastic material using an adhesive. Otherwise, it can be also formed by vacuum deposition, sputtering or coating. The organic material protective layer can be formed by the steps of dissolving the polymer material to prepare a polymer solution, coating the polymer solution to form a layer, and then drying the formed layer to give the protective layer. In the case of a UV curable resin, neat resinous material having no solvent or a solution of the resin may be applied and then cured by applying ultraviolet rays to the formed layer. The polymer solution for protective layer can optionally contain various additives such as anti-static agents, oxidation inhibitors and UV absorbers. Besides on the light-reflecting layer, another protective layer can be also placed on the face not having the recording dye layer so as to enhance the scratch resistance and the moisture resistance of the medium. The thickness of the protective layer is generally in the range of 0.1 to 100 µm.

    [0170] The recording/reproducing procedures with an optical disc of CD-R type are carried out, for example, in the following manner.

    [0171] Using an optical disc of CD-R type, the information recording/reproducing can be carried out not only at a normal line rate (1.2 to 1.4 m/sec.) but also at a twofold line rate, a fourfold line rate and a sixfold or more line rate.

    [0172] The optical disc is made to rotate at a predetermined line rate (1.2 to 1.4 m/sec., in the case of CD format), or a predetermined angular rate. On the rotating disc, a recording light source such as a semiconductor laser beam is applied through the transparent substrate. By the application of the laser beam, irradiated area of the recording layer is locally heated to change the physical or chemical characteristics, and thus pits are formed in the recording layer to record the information. The light source preferably is a semiconductor laser having an oscillation frequency in the range of 500 to 850 nm. The preferred beam wavelength is in the range of 500 to 800 nm. In the case of the optical disc of CD-R type, the laser beam preferably has a wavelength of 770 to 790 nm. The reproduction of the recorded information can be accomplished by applying a semiconductor laser beam on the optical disc rotating at a predetermined line rate. The light-reflection is then detected from the transparent substrate side.

    [0173] The preparation of optical information recording medium of the invention is described above with respect to an optical disc of CD-R type, as an example. However, the invention can be also used for an optical disc of DVD-R type.

    [0174] The present invention is further described by the following examples.

    [Example 1]



    [0175] A container having a lid provided with a hole for releasing the vapor was prepared. The upper part of the container had a small cross section. In this container, a dye solution for recording layer was prepared in the following manner.


    (1) Preparation of dye solution



    [0176] Into the container, 1.5 g of an indolenine type cyanine dye shown above and 100 mL of 1,1,2,2,3,3,4-heptafluorocyclopentane [Zeorola H (trade name), available from Nippon Zeon Co. Ltd., boiling point: 82.5°C] were introduced at room temperature (25°C). The mixture was then heated for 10 minutes to 60°C. While the temperature was kept at 60°C, ultrasonic waves were applied for 1 hour to dissolve the dye. Thus, the dye solution for recording layer was prepared.

    [0177] The dye solution was cooled to 25°C, and applied by spin-coat on the surface (on which pregroove was formed) of a polycarbonate substrate disc (outer diameter: 120 mm, inner diameter: 15 mm, thickness: 1.2 mm) and then dried to give a recording dye layer (thickness at the pregroove: approx. 180 nm). The pregroove was beforehand formed spirally on the substrate (track pitch: 1.6 µm, pregroove width: 500 nm, depth at pregroove: 175 nm) by injection molding.

    [0178] On thus-formed dye layer, a light-reflecting layer made of Ag (thickness: about 150 nm) was provided by sputtering with DC magnetron sputtering apparatus. On thus-formed light-reflecting metal layer, a UV curable photopolymer (Daicureclear SD-318 [trade name], available from Dainippon Ink & Chemicals, Inc.) was further applied by spin-coat, and then irradiated with ultraviolet rays of a metal halide lamp to be cured to form a resin protective layer of about 8 µm thickness.

    [0179] Thus, an optical disc of CD-R type (hereinafter simply referred to as "CD-R") comprising a substrate, a recording dye layer, a light-reflecting metal layer and a resin protective layer overlaid in order was produced according to the present invention.

    [Examples 2 to 10]



    [0180] The procedure for the preparation of dye solution described in Example 1 was repeated except for replacing the dye with one of the cyanine or oxonol dyes set forth in Table 2, to prepare an optical disc.
    Table 2
    Example No.Dye (Dye No.)Amount
    Example 2 Cyanine dye (I-43) 1.5 g
    Example 3 Cyanine dye (I-17) 1.5 g
    Example 4 Cyanine dye (I-62) 0.9 g
      Cyanine dye (I-17) 0.4 g
      Cyanine dye (I-11) 0.2 g
    Example 5 Cyanine dye (I-12) 1.5 g
    Example 6 Cyanine dye (I-101) 1.5 g
    Example 7 Cyanine dye (1-104) 1.5 g
    Example 8 Cyanine dye (1-123) 1.5 g
    Example 9 Cyanine dye (1-124) 1.5 g
    Example 10 Oxonol dye (1 in Table 1) 1.5 g

    [Evaluation of Optical Disc]



    [0181] Onto the optical disc of Example 1, EFM signals were recorded with a laser beam of 780 nm through a NA 0.5 pick-up (line rate: 4.8 m/sec.) by means of OTM-2000 ([trade name], available from Pulstech) at the optimum power while the power varies in the range of 3 to 10 mW. The recorded signals were then reproduced with a laser beam of 780 nm through a NA0.45 pick-up (line rate: 1.2 m/sec.) by means of CD-CATS (trade name, available from Audio Development) at the laser power of 0.5 mW, and thereby 11T land jitter (jitter between pits) at the position 40 mm from the center position was measured by means of TIA (available from Hewlett Packard). A small jitter value indicates that the recorded signals are uniform.

    [0182] The results are shown in Table 3.
    Table 3
    11T land jitter (ns)
    Example 1 31

    [Examples 11 to 14]



    [0183] The procedure for the preparation of dye solution described in Example 1 was repeated except for replacing the solvent with a combination of 1,1,2,2,3,3,4-heptafluorocyclopentane (HFCP) and dichloromethane (DCM, for Examples 11 to 13) in the ratio set forth in Table 4, or dichloroethane (DCE, for Example 14) in the ratio set forth in Table 4, to prepare an optical disc.

    [Evaluation of Optical Disc]



    [0184] The optical discs of Examples 11 to 14 were evaluated in the aforementioned manner with respect to 11T land jitter (jitter between pits) at the positions 40 mm and 57 mm from the center position.

    [0185] The results are shown in Table 4.
    Table 4
    ExampleSolvent mixture (vol. ratio)11T land jitter (ns)
    40 mm57 mm
    Ex. 11 HFCP/DCM (99/1) 31 33
    Ex. 12 HFCP/DCM (98/2) 31 33
    Ex. 13 HFCP/DCM (95/5) 33 34
    Ex. 14 HFCP/DCE (95/5) 32 33

    [Examples 15 and 16]



    [0186] The procedure for the preparation of dye solution described in Example 1 was repeated except for replacing the solvent with a combination of 1,1,2,2,3,3,4-heptafluorocyclopentane (HFCP) and 2,2,3,3-tetrafluoroalcohol (TFP, for Example 15) in the ratio set forth in Table 5, or diacetone alcohol (DAA, for Example 16) in the ratio set forth in Table 5, to prepare an optical disc.

    [Comparison Example 1]



    [0187] The procedure for the preparation of dye solution described in Example 1 was repeated except for replacing the solvent with 2,2,3,3-tetrafluoroalcohol, to prepare an optical disc.

    [Evaluation of Optical Dics]



    [0188] The optical discs of Examples 15 and 16 as well as Comparison Example 1 were evaluated in the aforementioned manner with respect to 11T land jitter (jitter between pits) at the positions 40 mm and 57 mm from the center position.

    [0189] The results are shown in Table 5.
    Table 5
    ExampleSolvent mixture (vol. ratio)11T land jitter (ns)
    40 mm57 mm
    Ex. 15 HFCP/TFP (90/10) 30 31
    Ex. 16 HFCP/DAA (95/5) 31 32
    Com. 1 TFP (100) 36 41

    [Examples 17 to 21]



    [0190] The procedure for the preparation of dye solution described in Example 1 was repeated except for replacing the solvent with a combination of 2,2,3,3-tetrafluoroalcohol (TFP) and 1,1,2,2,3,3,4-heptafluorocyclopentane (HFCP) in the ratio set forth in Table 6 in the ratio set forth in Table 5, to prepare an optical disc.

    [0191] In the preparation, the time required for drying the coated dye solution was measured.

    [Comparison Example 2]



    [0192] The procedure for the preparation of dye solution described in Example 1 was repeated except for replacing the solvent with 2,2,3,3-tetrafluoroalcohol, to prepare an optical disc.

    [0193] In the preparation, the time required for drying the coated dye solution was measured.

    [Evaluation of Optical Dics]



    [0194] The optical discs of Examples 17 and 21 as well as Comparison Example 2 were evaluated in the aforementioned manner with respect to 11T land jitter (jitter between pits) at the positions 40 mm from the center position.

    [0195] The results are shown in Table 6.
    Table 6
    ExampleSolvent (TFP/HFCP), (vol. ratio)Time for Dryness (sec.)11T land jitter (ns)
    40 mm
    Ex. 17 95/5 13 32
    Ex. 18 85/15 11 32
    Ex. 19 75/25 10 31
    Ex. 20 65/35 9 32
    Ex. 21 55/45 8 34
    Com. 2 TFP (100) 16 34



    Claims

    1. A process for the preparation of an optical information recording disc comprising the steps of coating a dye solution on a transparent substrate disc and drying the coated dye solution, characterized in that the dye solution comprises a laser-light sensitive organic dye dissolved in an organic solvent comprising 1,1,2,2,3,3,4-heptafluorocyclopentane.
     
    2. The process of claim 1, wherein the dye solution is prepared by the steps of mixing the organic dye and the organic solvent and keeping the resulting mixture at a temperature of higher than 45°C but lower than a boiling temperature of the organic solvent by at least 10°C for a period of 5 minutes to 2 hours.
     
    3. The process of claim 1, wherein the organic solvent comprises 1,1,2,2,3,3,4-heptafluorocyclopentane and an organic liquid which has a boiling point higher than that of 1,1,2,2,3,3,4-heptafluorocyclopentane, which is essentially inert to the substrate, and in which the dye is soluble, in a volume ratio of 99:1 to 51:49.
     
    4. The process of claim 3, wherein the organic liquid has a boiling point of lower than 250°C but higher than that of 1,1,2,2,3,3,4-heptafluorocyclopentane by at least 10°C.
     
    5. The process of claim 3, wherein the organic liquid is selected from the group consisting of an aliphatic ketone, an aliphatic hydrocarbon, an alicyclic hydrocarbon, a carboxylic acid ester, an aliphatic ether, and an alcohol.
     
    6. The process of claim 3, wherein the organic liquid is a fluorinated alcohol having one of the formulas of CF3CH2OH, HCF2CF2OH, H(CF2CF2)2CH2OH, and H (CF2CF2)3CH2OH.
     
    7. The process of claim 3, wherein the organic liquid is a ketoalcohol.
     
    8. The process of claim 7, wherein the ketoalcohol is diacetone alcohol.
     
    9. The process of claim 1, wherein the organic solvent comprises 1,1,2,2,3,3,4-heptafluorocyclopentane and an organic liquid which has a solubility for the dye higher than that of 1,1,2,2,3,3,4-heptafluorocyclopentane and which is active to the substrate, in a volume ratio of 99.9:0.1 to 80:20.
     
    10. The process of claim 9, wherein the organic liquid is selected from the group consisting of a halogenated aliphatic hydrocarbon, an aromatic hydrocarbon, a ketone, a sulfoxide, an amide, a carboxylic acid ester, an ether, and a nitrile.
     
    11. The process of claim 9, wherein the organic liquid is a halogenated aliphatic hydrocarbon selected from the group consisting of dichloromethane, dichloroethane, and tetrachloroethane.
     
    12. The process of claim 9, wherein the organic liquid is acetone.
     
    13. The process of claim 1, wherein the solvent comprises 1,1,2,2,3,3,4-heptafluorocyclopentane and a fluorinated alcohol in a volume ratio of 50:50 to 1:99.
     
    14. The process of claim 13, wherein the fluorinated alcohol is 2,2,3,3-tetrafluoro-1-propanol.
     
    15. A dye solution which comprises a laser-light sensitive organic dye dissolved in an organic solvent comprising 1,1,2,2,3,3,4-heptafluorocyclopentane.
     
    16. The dye solution of claim 15, which is prepared by the steps of mixing the organic dye and the organic solvent and keeping the resulting mixture at a temperature of higher than 45°C but lower than a boiling temperature of the organic solvent by at least 10°C for a period of 5 minutes to 2 hours.
     
    17. The dye solution of claim 15, wherein the solvent comprises 1,1,2,2,3,3,4-heptafluorocyclopentane and an organic liquid which has a boiling point higher than that of 1,1,2,2,3,3,4-heptafluorocyclopentane, which is essentially inert to the substrate, and in which the dye is soluble, in a volume ratio of 99:1 to 51:49.
     
    18. The dye solution of claim 15, wherein the organic liquid is a fluorinated alcohol having one of the formulas of CF3CH2OH, HCF2CF2CH2OH, H(CF2CF2)2CH2OH, and H (CF2CF2)3CH2OH.
     
    19. The dye solution of claim 15, wherein the organic solvent comprises 1,1,2,2,3,3,4-heptafluorocyclopentane and an organic liquid which has a solubility for the dye higher than that of 1,1,2,2,3,3,4-heptafluorocyclopentane and which is active to the substrate, in a volume ratio of 99.9:1 to 80:20.
     
    20. The dye solution of claim 15, wherein the solvent comprises 1,1,2,2,3,3,4-heptafluorocyclopentane and a fluorinated alcohol in a volume ratio of 50:50 to 1:99.
     


    Revendications

    1. Procédé de préparation d'un disque d'enregistrement d'informations optiques comprenant les étapes consistant à revêtir une solution de teinte sur un disque de substrat transparent et sécher la solution de teinte revêtue, caractérisé en ce que la solution de teinte comprend une teinte organique sensible à la lumière laser dissoute dans un solvant organique comprenant du 1,1,2,2,3,3,4-heptafluorocyclopentane.
     
    2. Procédé selon la revendication 1, dans lequel la solution de teinte est préparée par les étapes consistant à mélanger la teinte organique et le solvant organique et à maintenir le mélange résultant à une température plus élevée que 45 °C mais plus basse qu'une température d'ébullition du solvant organique d'au moins 10 °C pendant une période de 5 minutes à 2 heures.
     
    3. Procédé selon la revendication 1, dans lequel le solvant organique comprend du 1,1,2,2,3,3,4-heptafluorocyclopentane et un liquide organique qui a un point d'ébullition plus élevé que celui du 1,1,2,2,3,3,4-heptafluorocyclopentane, qui est essentiellement inerte pour le substrat, et dans lequel la teinte est soluble, en un rapport en volume de 99 : 1 à 51: 49.
     
    4. Procédé selon la revendication 3, dans lequel le liquide organique a un point d'ébullition plus bas que 250 °C mais plus élevé que celui du 1,1,2,2,3,3,4-heptafluorocyclopentane d'au moins 10 °C.
     
    5. Procédé selon la revendication 3, dans lequel le liquide organique est choisi dans le groupe consistant en une cétone aliphatique, un hydrocarbure aliphatique, un hydrocarbure alicyclique, un ester d'acide carboxylique, un éther aliphatique et un alcool.
     
    6. Procédé selon la revendication 3, dans lequel le liquide organique est un alcool fluoré ayant l'une des formules CF3CH2OH, HCF2CF2CH2OH, H(CF2CF2)2CH2OH et H(CF2CF2)3CH2OH.
     
    7. Procédé selon la revendication 3, dans lequel le liquide organique est un cétoalcool.
     
    8. Procédé selon la revendication 7, dans lequel le cétoalcool est un diacétone alcool.
     
    9. Procédé selon la revendication 1, dans lequel le solvant organique comprend du 1,1,2,2,3,3,4-heptafluorocyclopentane et un liquide organique qui a une solubilité pour la teinte plus élevée que celle du 1,1,2,2,3,3,4-heptafluorocyclopentane et qui est actif pour le substrat, en un rapport en volume de 99,9 : 0,1 à 80 : 20.
     
    10. Procédé selon la revendication 9, dans lequel le liquide organique est choisi dans le groupe consistant en un hydrocarbure aliphatique halogéné, un hydrocarbure aromatique, une cétone, un sulfoxide, un amide, un ester d'acide carboxylique, un éther et un nitrile.
     
    11. Procédé selon la revendication 9, dans lequel le liquide organique est un hydrocarbure aliphatique halogéné choisi dans le groupe consistant en le dichlorométhane, le dichloroéthane et le tétrachloroéthane.
     
    12. Procédé selon la revendication 9, dans lequel le liquide organique est l'acétone.
     
    13. Procédé selon la revendication 1, dans lequel le solvant comprend du 1,1,2,2,3,3,4-heptafluorocyclopentane et un alcool fluoré en un rapport en volume de 50 : 50 à 1 : 99.
     
    14. Procédé selon la revendication 13, dans lequel l'alcool fluoré est le 2,2,3,3-tétrafluoro-1-propanol.
     
    15. Solution de teinte qui comprend une teinte organique sensible à la lumière laser dissoute dans un solvant organique comprenant du 1,1,2,2,3,3,4-heptafluorocyclopentane.
     
    16. Solution de teinte selon la revendication 15, qui est préparée par les étapes consistant à mélanger la teinte organique et le solvant organique et à maintenir le mélange résultant à une température plus élevée que 45 °C mais plus basse qu'une température d'ébullition du solvant organique d'au moins 10 °C pendant une période de 5 minutes à 2 heures.
     
    17. Solution de teinte selon la revendication 15, dans laquelle le solvant comprend du 1,1,2,2,3,3,4-heptafluorocyclopentane et un liquide organique qui a un point d'ébullition plus élevé que celui du 1,1,2,2,3,3,4-heptafluorocyclopentane, qui est essentiellement inerte pour le substrat, et dans lequel la teinte est soluble, en un rapport en volume de 99 : 1 à 51 : 49.
     
    18. Solution de teinte selon la revendication 15, dans laquelle le liquide organique est un alcool fluoré ayant l'une des formules CF3CH2OH, HCF2CF2CH2OH, H(CF2CF2)2CH2OH et H(CF2CF2)3CH2OH.
     
    19. Solution de teinte selon la revendication 15, dans laquelle le solvant organique comprend du 1,1,2,2,3,3,4-heptafluorocyclopentane et un liquide organique qui a une solubilité pour la teinte plus élevée que celle du 1,1,2,2,3,3,4-heptafluorocyclopentane et qui est actif pour le substrat, en un rapport en volume de 99,9 : 0,1 à 80:20.
     
    20. Solution de teinte selon la revendication 15, dans laquelle le solvant comprend du 1,1,2,2,3,3,4-heptafluorocyclopentane et un alcool fluoré en un rapport en volume de 50: 50 à 1: 99.
     


    Ansprüche

    1. Verfahren zur Herstellung einer optischen, Informationen aufzeichnenden Disk, umfassend die Schritte des beschichtungsmäßigen Aufbringens einer Farbstoff-Lösung auf eine transparente Substrat-Disk und Trocknen der aufgebrachten Farbstoff-Lösung, dadurch gekennzeichnet, dass die Farbstoff-Lösung einen für Laser-Licht empfindlichen organischen Farbstoff umfasst, der in einem organischen Lösungsmittel gelöst ist, das 1, 1,2,2,3,3,4-Heptafluorcyclopentan umfasst.
     
    2. Verfahren nach Anspruch 1, worin die Farbstoff-Lösung hergestellt wird durch die Schritte des Mischens des organischen Farbstoffs und des organischen Lösungsmittels und Halten der resultierenden Mischung bei einer Temperatur höher als 45° C, jedoch um wenigstens 10° C unterhalb der Siede-Temperatur des organischen Lösungsmittels für eine Zeitdauer von 5 min bis 2 h.
     
    3. Verfahren nach Anspruch 1, worin das organische Lösungsmittel umfasst: 1,1,2,2,3,3,4-Heptafluorcyclopentan und eine organische Flüssigkeit, die einen Siedepunkt über demjenigen von 1,1,2,2,3,3,4-Heptafluorcyclopentan aufweist, welche im wesentlichen inert gegenüber dem Substrat ist und in der der Farbstoff löslich ist, in einem Volumen-Verhältnis von 99:1 bis 51:49.
     
    4. Verfahren nach Anspruch 3, worin die organische Flüssigkeit einen Siedepunkt unterhalb von 250° C hat, jedoch um wenigstens 10° C über dem des 1,1,2,2,3,3,4-Heptafluorcyclopentans.
     
    5. Verfahren nach Anspruch 3, worin die organische Flüssigkeit gewählt ist aus der Gruppe, die besteht aus einem aliphatischen Keton, einem aliphatischen Kohlenwasserstoff, einem alizyklischen Kohlenwasserstoff, einem Carbonsäureester, einem aliphatischen Ether und einem Alkohol.
     
    6. Verfahren nach Anspruch 3, worin die organische Flüssigkeit ein fluorierter Alkohol mit einer der Formeln CF3CH2OH, HCF2CF2CH2OH, H(CF2CF2)2CH2OH und H(CF2CF2)3CH2OH ist.
     
    7. Verfahren nach Anspruch 3, worin die organische Flüssigkeit ein Ketoalkohol ist.
     
    8. Verfahren nach Anspruch 7, worin der Ketoalkohol Diacetonalkohol ist.
     
    9. Verfahren nach Anspruch 1, worin das organische Lösungsmittel umfasst: 1,1,2,2,3,3,4-Heptafluorcyclopentan und eine organische Flüssigkeit, die eine Löslichkeit für den Farbstoff über derjenigen von 1,1,2,2,3,3,4-Heptafluorcyclopentan aufweist und die gegenüber dem Substrat aktiv ist, in einem Volumen-Verhältnis von 99,9:0,1 bis 80:20.
     
    10. Verfahren nach Anspruch 9, worin die organische Flüssigkeit gewählt ist aus der Gruppe, die besteht aus einem halogenierten aliphatischen Kohlenwasserstoff, einem aromatischen Kohlenwasserstoff, einem Keton, einem Sulfoxid, einem Amid, einem Carbonsäureester, einem Ether und einem Nitril.
     
    11. Verfahren nach Anspruch 9, worin die organische Flüssigkeit ein halogenierter aliphatischer Kohlenwasserstoff ist, der gewählt ist aus der Gruppe, die besteht aus Dichlormethan, Dichlorethan und Tetrachlorethan.
     
    12. Verfahren nach Anspruch 9, worin die organische Flüssigkeit Aceton ist.
     
    13. Verfahren nach Anspruch 1, worin das Lösungsmittel 1,1,2,2,3,3,4-Heptafluorcyclopentan und einen fluorierten Alkohol in einem Volumen-Verhältnis von 50:50 bis 1:99 umfasst.
     
    14. Verfahren nach Anspruch 13, worin der fluorierte Alkohol 2,2,3,3-Tetrafluor-1-propanol ist.
     
    15. Farbstofflösung, die einen für Laser-Licht empfindlichen organischen Farbstoff gelöst in einem organischen Lösungsmittel umfasst, das 1,1,2,2,3,3,4-Heptafluorcyclopentan umfasst.
     
    16. Farbstofflösung nach Anspruch 15, die hergestellt wird durch die Schritte des Mischens des organischen Farbstoffs und des organischen Lösungsmittels und Haltens der resultierenden Mischung bei einer Temperatur über 45° C, jedoch um wenigstens 10° C unterhalb der Siede-Temperatur des organischen Lösungsmittels für eine Zeitdauer von 5 min bis 2 h.
     
    17. Farbstofflösung nach Anspruch 15, worin das Lösungsmittel 1,1,2,2,3,3,4-Heptafluorcyclopentan und eine organische Flüssigkeit umfasst, die einen Siedepunkt über dem von 1,1,2,2,3,3,4-Heptafluorcyclopentan aufweist, die im wesentlichen inert gegenüber dem Substrat ist und in der der Farbstoff löslich ist, in einem Volumen-Verhältnis 99:1 bis 51:49.
     
    18. Farbstofflösung nach Anspruch 15, worin die organische Flüssigkeit ein fluorierter Alkohol ist, der eine der folgenden Formeln aufweist: CF3CH2OH, HCF2CF2CH2OH, H(CF2CF2)2CH2OH und H(CF2CF2)3CH2OH.
     
    19. Farbstofflösung nach Anspruch 15, worin das organische Lösungsmittel 1,1,2,2,3,3,4-Heptafluorcyclopentan und eine organische Flüssigkeit umfasst, die eine Löslichkeit für den Farbstoff aufweist, die höher ist als diejenige von 1,1,2,2,3,3,4-Heptafluorcyclopentan, und aktiv gegenüber dem Substrat ist, in einem Volumen-Verhältnis 99,9:0,1 bis 80:20.
     
    20. Farbstofflösung nach Anspruch 15, worin das Lösungsmittel 1,1,2,2,3,3,4-Heptafluorcyclopentan und einen fluorierten Alkohol in einem Volumen-Verhältnis 50:50 bis 1:99 umfasst.