JP2000070824A - Regeneration of coating solution for producing optical data recording medium, regenerated coating solution and production of optical data recording medium utilizing regenerated coating solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To markedly simplify a production process by reducing the load in a recovery process, in the production of an optical data recording medium. SOLUTION: A coating soln. regenerating method includes a process for dripping a coating soln. containing a coloring matter and a fading preventing agent on the inner-peripheral side of the surface of a disc-shaped transparent resin substrate horizontally held in a spin coater to spread the same to the outer peripheral side of the substrate by the rotation of the substrate and discharging the excessive coating soln. from the outer peripheral edge part of the substrate to the outside to recover this coating waste soln. in a waste soln. recovery device, a process determining the contents of the coloring matter and the fading preventing agent in this coating waste soln. and a process adjusting the concn. of the coloring matter and the fading preventing agent in the coating waste soln. and that of the coloring matter and the fading preventing agent in the original coating soln. so as to allow them to coincide with each other in accuracy of two or more figures.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for regenerating a coating solution used for manufacturing an optical information recording medium, a regenerating coating solution obtained by the method, and a method for manufacturing an optical information recording medium using the regenerated coating solution. It is about the method.

[0002]

2. Description of the Related Art The spin coating method has been conventionally used as an advantageous method when manufacturing an optical disk. In this method, the coating liquid is dropped on the inner peripheral side of the rotating substrate,
The coating liquid is cast on the outer peripheral side by centrifugal force to form a coating film, and the excess coating liquid is shaken off from the outer peripheral edge of the substrate and released to the surroundings, and then the solvent is dried and removed from the coating film This is a method of forming a thin film. As a typical optical disk, for example, a structure in which a dye recording layer, a reflective layer, and a protective layer are laminated in this order on a disk-shaped transparent resin substrate (hereinafter, referred to as a disk-shaped substrate or simply a substrate) is used. On a CD-R type optical disk or a disk-shaped transparent resin substrate, a laminated body composed of a dye recording layer, a reflection layer, and a protective layer provided as desired, and a disk-shaped transparent resin substrate (protection substrate) are provided with the recording layer inside. DVD-R type optical disc or a DVD-R type optical disc having a structure in which the above two laminated bodies are bonded with an adhesive such that their recording layers are inside. -There is an R type optical disk. In many cases, a spin coating method is used for forming the dye recording layer and the protective layer of these optical disks. For example,
In the method of manufacturing a CD-R type optical disk described in the above item, a spin coating method is used for forming the dye recording layer and the protective layer.

FIG. 1 is a schematic cross-sectional view of a general spin coating apparatus for performing a spin coating method. As shown in FIG. 1, the spin coater 10 includes a coating liquid applying device 11, a spinner head device 13, a scattering prevention wall 15, and an exhaust device 18. Coating liquid application device 1
Reference numeral 1 denotes a nozzle 12 including a pressurized tank (not shown) and a discharge amount adjusting valve (not shown). A predetermined amount of the coating liquid is dropped onto the surface of the disk-shaped substrate 1 through the nozzle 12. Has become. The coating liquid applying device 11 is operated by a handling mechanism (not shown).
It is configured to be able to move from the standby position to a predetermined position above the substrate 1. The spinner head device 13 is disposed below the coating liquid application device, and holds the disk-shaped substrate 1 horizontally by a detachable fixing member 14 and can rotate the shaft by a driving motor (not shown). It has been. The above-mentioned coating liquid applying device 1 is placed on the substrate 1 rotating while being held horizontally by a spinner head.
The coating liquid dropped from one nozzle 12 is cast on the substrate surface to the outer peripheral side. Then, the excess coating solution is shaken off at the outer peripheral edge of the substrate, discharged to the outside, and then dried to form a coating film on the substrate surface. The scattering prevention wall 15 is provided to prevent the excess coating liquid discharged from the outer peripheral edge of the substrate to the outside, from scattering around, and the spinner head device is formed so that the opening 16 is formed at the upper part. 13 are arranged. Excess coating liquid collected through the scattering prevention wall is drained from the drain 17.
It is to be collected through. The exhaust device 18 is configured to allow air taken in from the opening 16 formed above the scattering prevention wall to flow over the substrate surface, and then exhaust the air from below the spinner head device 13. (Not shown) and an exhaust fan 19, and the drying conditions of the coating film can be changed by adjusting the exhaust amount (exhaust air velocity).

[0004]

As described above, in the spin coating method, an excess coating solution is shaken off from the outer peripheral portion of the substrate, discharged to the periphery, and collected as a waste liquid. The amount actually applied is about 2 times the ejection amount
It is a percentage. The remaining 80% of the coating liquid is sent from the waste liquid reservoir to the recovery step, where the solvent and impurities are removed, and only the expensive dye is isolated and recovered. If this coating waste liquid can be used while containing a solvent and impurities, the load on the recovery step can be significantly reduced, and the manufacturing cost can be significantly reduced. However, the coating waste liquid differs from the coating liquid before coating in the following points. (1) The solvent is volatilized and the coating waste liquid becomes highly concentrated. (2) It is not easy to re-adjust the coating waste liquid changed in this way to the original composition because of the coating liquid such as a dye and an anti-fading agent due to precipitation and adhesion in the spin coater.
Heretofore, it has not been performed to reuse the coating waste liquid while keeping the solvent and impurities contained.

Accordingly, an object of the present invention is to provide a method for regenerating a coating solution used for producing an optical information recording medium, in particular, a dye-containing coating solution used for forming a recording layer, a regenerating coating solution obtained by the method, Another object of the present invention is to provide a method for manufacturing an optical information recording medium using the regenerating coating solution.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the above means can be solved by the following means, and have completed the present invention.

That is, according to the present invention, a coating solution containing a dye and an anti-fading agent is dropped on the inner peripheral side of the surface of a disk-shaped transparent resin substrate horizontally held in a spin coater, and the substrate is rotated. A step of casting the coating solution on the outer peripheral side and discharging excess coating liquid outward from the outer peripheral edge of the substrate to collect the coating waste liquid in a waste liquid collecting device; Quantifying the content of the anti-fading agent and adjusting the concentrations of the dye and the anti-fading agent in the coating waste liquid so as to match the concentrations of the dye and the anti-fading agent in the coating solution with a precision of two digits or more. And a method of regenerating the coating liquid for producing an optical information recording medium.

Further, the present invention provides a method in which a coating solution containing a dye and an anti-fading agent is dropped on the inner peripheral side of the surface of a disk-shaped transparent resin substrate horizontally held in a spin coater, and the substrate is rotated. The coating liquid is cast on the outer peripheral side, and excess coating liquid is discharged outward from the outer peripheral edge of the substrate, and the coating waste liquid is collected in a waste liquid collecting device, and dyes in the coating waste liquid and prevention of fading are prevented. After quantifying the content of the coating solution, the recoating was performed by adjusting the concentrations of the dye and the anti-fading agent in the coating waste liquid so as to match the concentrations of the dye and the anti-fading agent in the coating solution with a precision of two digits or more. Liquid.

Further, according to the present invention, the reclaimed coating liquid of the present invention is dropped on the inner peripheral side of the surface of a disk-shaped transparent resin substrate horizontally held in a spin coater, and the coating liquid is rotated by rotation of the substrate. Is spread to the outer peripheral side, and excess coating liquid is discharged outward from the outer peripheral edge of the substrate, and the coating waste liquid is collected in a waste liquid collecting device, and the coating film is dried to obtain a dye-containing recording. This is a method for manufacturing an optical information recording medium having a step of forming a layer.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
As an optical information recording medium, as shown in FIG. 2, an optical disc 40 having a configuration in which a dye recording layer 2, a reflective layer 3, and a protective layer 4 are laminated on a disc-shaped transparent resin substrate 1 in this order.
Is common.

Examples of the substrate material include polycarbonate; acrylic resins such as polymethyl methacrylate; vinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymer; epoxy resins; amorphous polyolefin and polyester. May be used in combination. Among the above materials, polycarbonate is preferred from the viewpoints of moisture resistance, dimensional stability, cost, and the like.

It is preferable that a tracking groove or a pre-groove representing information such as an address signal is formed on the substrate. This pregroove is preferably formed directly on the substrate when injection molding or extrusion molding of a resin material such as polycarbonate. Pregroove depth is 0.01-0.3μm
Is preferable, and the half-value width is in the range of 0.1.
It is preferably in the range of 2 to 0.9 μm.

A dye recording layer is provided on a disk-shaped substrate made of the above material. The dye used in the dye recording layer is not particularly limited. Examples of usable dyes include cyanine dyes, phthalocyanine dyes, imidazoquinoxaline dyes, pyrylium / thiopyrylium dyes, azurenium dyes, squalilium dyes, metal complex dyes such as Ni and Cr, naphthoquinone dyes, and anthraquinone dyes. Dyes, indophenol dyes, indoaniline dyes, triphenylmethane dyes, merocyanine dyes, oxonol dyes, aminium / diimmonium dyes, and nitroso compounds. Among these dyes, a cyanine dye is preferable, and a benzoindolenine dye is more preferable.
Is particularly preferable.

[0014]

Embedded image General formula (1)

R ^{1 in the} general formula (1) represents a monovalent substituent. As the monovalent substituent, a substituted or unsubstituted alkyl group is preferable. The alkyl group is preferably an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, and particularly preferably an alkyl group having 1 to 4 carbon atoms. The alkyl group may be linear or branched, and examples of the substituent include a halogen atom such as a fluorine atom and a chlorine atom; an alkoxy group such as a methoxy group and an ethoxy group; an alkylthio group such as a methylthio group and an ethylthio group; Acyl groups; hydroxy groups; alkoxycarbonyl groups such as ethoxycarbonyl groups; alkenyl groups such as vinyl groups; and aryl groups such as phenyl groups. R ² and R ^{3 in} the general formula (1) each independently represent a monovalent substituent. As the monovalent substituent, a substituted or unsubstituted alkyl group is preferable. The alkyl group has 1 to 4 carbon atoms.
Is preferred, and a methyl group and an ethyl group are particularly preferred. R ² and R ³ may combine with each other to form a ring. R ^{4 in the} general formula (1) represents a monovalent substituent.
As the monovalent substituent, a hydrogen atom, an alkyl group having 1 to 16 carbon atoms, a halogen atom, and an aralkyl group are preferable, and a methyl group, an ethyl group, and a benzyl group are more preferable.
A methyl group is particularly preferred. X ^{n− in the} general formula (1) represents an anion, and n represents 1, 2, or 3. As anions, halide ions, sulfonate ions, ClO _{4
^{-, BF 4 -, SbF 5}} -, may be mentioned metal complex ions, phosphate ions. Among these, a divalent anion (n = 2) is preferable, and a divalent anion represented by the following general formula (2) is particularly preferable.

[0016]

Embedded image General formula (2)

R ^{5 to} R ¹⁰ in the general formula (2) each independently represent a monovalent substituent. As the monovalent substituent, a hydrogen atom, an alkyl group, a halogen atom, and an aralkyl group are preferable, a hydrogen atom, an alkyl group having 8 or less carbon atoms is more preferable, and a methyl group is particularly preferable.

As the coating solution, a dye solution in which a dye is dissolved in an appropriate solvent is used. The concentration of the dye in the coating solution is generally in the range of 0.01 to 15% by weight, preferably 0.1 to 15% by weight.
It is in the range from 1 to 10% by weight, particularly preferably in the range from 0.5 to 5% by weight, most preferably in the range from 0.5 to 3% by weight.

Examples of the solvent for the coating solution for forming the dye recording layer include esters such as butyl acetate and cellosolve acetate; methyl ethyl ketone, cyclohexanone, and the like.
Ketones such as methyl isobutyl ketone; chlorinated hydrocarbons such as dichloromethane, 1,2-dichloroethane and chloroform; amides such as dimethylformamide; hydrocarbons such as cyclohexane; ethers such as tetrahydrofuran, ethyl ether and dioxane;
alcohols such as n-propanol, isopropanol, n-butanol, diacetone alcohol;
Fluorinated solvents such as 3,3-tetrafluoropropanol; and glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and propylene glycol monomethyl ether. The above-mentioned solvents can be used alone or in combination of two or more in consideration of the solubility of the dye used. Preferably, it is a fluorinated solvent such as 2,2,3,3-tetrafluoropropanol. In the coating solution, an anti-fading agent or a binder may be added as desired, and various additives such as an antioxidant, a UV absorber, a plasticizer, and a lubricant may be added according to the purpose. May be.

Representative examples of the anti-fading agent include a nitroso compound, a metal complex, a diimmonium salt, and an aminium salt. These examples are described in, for example, JP-A-2-300288, JP-A-3-224793, and JP-A-4-224793.
No. 146189. In the present invention, an anti-fading agent represented by the following general formula (3) is preferable.

[0021]

Embedded image General formula (3)

R ¹¹ and R ^{12 in} formula (3) each independently represent a hydrogen atom or a monovalent substituent. R ¹¹ and R ¹²
Is a halogen atom, or a carbon atom,
A substituent formed by combining an oxygen atom, a nitrogen atom, or a sulfur atom. A hydroxy group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an acyloxy group, an amino group, an alkylamino group, an amide group, a sulfonamide group, a sulfamoylamino group, an alkoxycarbonylamino group, an alkoxysulfonylamino group, Ureido group, thioureido group, acyl group, alkoxycarbonyl group, carbamoyl group, alkylsulfonyl group, alkylsulfinyl group,
Examples include a sulfamoyl group, a carboxyl group (including a salt), and a sulfo group (including a salt). These may be further substituted with these substituents.

R ¹¹ and R ¹² each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a halogen atom, a cyano group, an alkoxy group having 1 to 6 carbon atoms, an alkylthio group having 1 to 6 carbon atoms, An amide group having 1 to 6 carbon atoms, a sulfonamide group having 1 to 6 carbon atoms, an ureido group having 1 to 6 carbon atoms, an acyl group having 1 to 6 carbon atoms, an alkoxycarbonyl group having 2 to 6 carbon atoms, A carbamoyl group having 6 carbon atoms, an alkylsulfonyl group having 1 to 6 carbon atoms, and an alkylsulfinyl group having 1 to 6 carbon atoms are preferable, an alkoxy group having 4 or less carbon atoms is more preferable, and a methoxy group and an ethoxy group are particularly preferable.

Examples of the binder include natural organic high molecular substances such as gelatin, cellulose derivatives, dextran, rosin and rubber; and hydrocarbon resins such as polyethylene, polypropylene, polystyrene and polyisobutylene, polyvinyl chloride and polyvinyl chloride. Vinylidene, polyvinyl chloride
Vinyl resins such as polyvinyl acetate copolymer, acrylic resins such as polymethyl acrylate and polymethyl methacrylate, polyvinyl alcohol, chlorinated polyethylene, epoxy resin, butyral resin, rubber derivatives, phenol
Synthetic organic polymers such as precondensates of thermosetting resins such as formaldehyde resins can be mentioned. When a binder is used, the amount of the binder used is generally 20 parts by weight or less, preferably 10 parts by weight, per 100 parts by weight of the dye.
It is at most 5 parts by weight, more preferably at most 5 parts by weight. The thickness of the dye recording layer is generally set in the range of 20 to 500 nm, preferably in the range of 50 to 300 nm.

An undercoat layer may be provided on the surface of the substrate on which the dye recording layer is provided, for the purpose of improving flatness, improving adhesive strength, preventing deterioration of the recording layer, and the like. As a material of the undercoat layer, for example, polymethyl methacrylate,
Acrylic acid / methacrylic acid copolymer, styrene / maleic anhydride copolymer, polyvinyl alcohol, N-methylol acrylamide, styrene / vinyl toluene copolymer, chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, Polyester, polyimide, vinyl acetate / vinyl chloride copolymer,
Examples include polymer substances such as an ethylene / vinyl acetate copolymer, polyethylene, polypropylene, and polycarbonate; and surface modifiers such as a silane coupling agent. The undercoat layer is prepared by dissolving or dispersing the above substance in an appropriate solvent to prepare a coating solution, and then applying this coating solution to the substrate surface using a coating method such as spin coating, dip coating, or extrusion coating. Can be formed. The thickness of the undercoat layer is generally 0.005 to 2
It is provided in a range of 0 μm, preferably in a range of 0.01 to 10 μm.

After that, a reflective layer is provided on the dye recording layer for the purpose of improving the reflectance particularly when information is reproduced. The light-reflective substance as the material of the reflection layer is a substance having a high reflectance to laser light, and there is no problem as long as the reflectance is 70% or more. Examples include Mg, Se,
Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo,
W, Mn, Re, Fe, Co, Ni, Ru, Rh, P
d, Ir, Pt, Cu, Ag, Au, Zn, Cd, A
1, Ga, In, Si, Ge, Te, Pb, Po, S
Metals such as n and Bi and semimetals or stainless steel can be mentioned. Preferred of these are:
Cr, Ni, Pt, Cu, Ag, Au, Al and stainless steel. These substances may be used alone,
Alternatively, two or more kinds may be used in combination. Alternatively, it may be used as an alloy. Particularly preferred are Au, Ag and alloys thereof. The reflection layer can be formed on the recording layer by, for example, vapor deposition, sputtering, or ion plating of the light reflective substance. The thickness of the reflective layer is generally in the range of 10 to 800 nm, preferably in the range of 20 to 500 nm, and more preferably in the range of 50 to 300 nm.

The protective layer is provided on the reflective layer for the purpose of physically and chemically protecting the dye recording layer and the like. The protective layer can also be provided on the side of the substrate on which the dye recording layer is not provided for the purpose of improving the scratch resistance and the moisture resistance. As a material used for the protective layer, for example, SiO, Si
Inorganic substances such as O ₂ , MgF ₂ , SnO ₂ , Si ₃ N ₄ ,
And organic substances such as thermoplastic resins, thermosetting resins, and UV curable resins.

The protective layer is formed, for example, by applying a film obtained by extrusion of a plastic to the reflective layer via an adhesive and / or
Alternatively, it can be formed by laminating on a substrate. Alternatively, it may be provided by a method such as vacuum deposition, sputtering, or coating. Also, thermoplastic resin,
In the case of thermosetting resins, they can also be formed by dissolving these in an appropriate solvent to prepare a coating solution, and then applying and drying this coating solution. In the case of a UV-curable resin, it can also be formed by preparing a coating solution as it is or by dissolving it in an appropriate solvent, applying the coating solution, and irradiating with UV light to cure. Various additives such as an antistatic agent, an antioxidant, and a UV absorber may be added to these coating solutions according to the purpose. The thickness of the protective layer is generally set in the range of 0.1 to 100 μm.

When manufacturing the above optical disk,
When forming a coating type layer such as an undercoat layer or a protective layer, the spin coating apparatus of the present invention can be used in the same manner as the dye recording layer.

The present invention relates to a method for regenerating a coating solution used in the step of forming a dye-containing recording layer in the method for producing an optical information recording medium described above. Hereinafter, a method of regenerating the coating liquid will be described in detail.

The method for regenerating a coating solution for producing an optical information recording medium according to the present invention is a method for coating a dye-containing and anti-fading agent on the inner peripheral side of the surface of a disk-shaped transparent resin substrate horizontally held in a spin coater. A liquid is dropped, and the coating liquid is cast to the outer peripheral side by rotating the substrate, and excess coating liquid is discharged outward from the outer peripheral edge of the substrate, and the coating waste liquid is collected in a waste liquid collecting device. And a step of quantifying the contents of the dye and the anti-fading agent in the coating waste liquid, and determining the concentrations of the dye and the anti-fading agent in the coating waste liquid by two times the concentrations of the dye and the anti-fading agent in the coating liquid. And adjusting the values so as to match each other with an accuracy of an order of magnitude or more.

(Waste liquid recovery step) The coating liquid dropped onto the substrate is spread on the substrate surface in the outer peripheral direction by rotation of the spinner head device, and reaches the outer peripheral edge of the substrate while forming a coating film. . The excess coating solution that has reached the outer peripheral edge is further shaken off by centrifugal force and scattered around the substrate edge. The excess coating liquid that has scattered collides with the scattering prevention wall, and is collected in a tray provided thereunder, and then collected through the drain. Further, from the viewpoint of suppressing the photodecomposition of the coating liquid, it is preferable that the container containing the recovered liquid has a light shielding property.

(Determination step of dye and the like in waste liquid) The determination of the dye and the anti-fading agent in the coating waste liquid may be performed by any quantification method. In consideration of the above, it is preferable to perform quantification by liquid chromatography. In the following step of adjusting the concentration of the dye or the like, in order to strictly adjust the concentrations of the dye and the anti-fading agent with the precision of two significant figures, it is preferable to perform the quantification with the precision of three or more significant figures. In order to achieve such high precision, first, as a separation condition, it is necessary that each peak of the dye and the anti-fading agent does not overlap with other peaks in the spectral absorption spectrum, and each peak is a single peak. is there. For example, using an indolenine-based dye (compound A) represented by the following structural formula as a dye,
In the case where an anti-fading agent (compound B) represented by the following structural formula was used as an anti-fading agent, liquid chromatography 3
FIG. 3 shows a dimensional chart (representing the relative detection intensity with respect to the elapsed time after injection at each measurement wavelength). The separation conditions in this case are as follows. (Separation conditions) Column: TSK-gel ODS-80Ts Column temperature: 25 ° C. Eluent: acetonitrile / water / acetic acid / triethylamine = 750/250/2/2 flow rate: 1 ml / min Pressure: 59 bar Detection wavelength: 254 nm Sample injection amount : 20 μm

[0034]

Embedded image

As can be seen from FIG. 3, under these conditions, the peaks of the dye and the anti-fading agent are separated without overlapping other peaks.

Next, the detection wavelength is preferably selected so that the detection accuracy of each compound is ensured by three or more significant figures. For the quantification of each compound, create a calibration curve at the detection wavelength,
It is usual to calculate the content concentration from the detected intensity based on this. Therefore, in order to increase the detection accuracy of each compound, it is preferable that the calibration curve at the detection wavelength has a large correlation coefficient. Conversely, a detection wavelength exhibiting such a high correlation must be selected. Generally, the detection intensity of the dye is large and there is no problem in the detection accuracy. Therefore, it is preferable in terms of detection accuracy to select a detection wavelength at which the detection intensity of the anti-fading agent is increased to some extent. For example, in the above-mentioned anti-fading agent, the detection wavelength is 45 as shown in the following table.
Since the correlation coefficient is maximum at 0.999 at 0 nm, 450 nm is preferably selected as the detection wavelength.

[0037]

[Table 1]

Further, in order to perform quantification with good reproducibility, the injection accuracy of the sample is preferably two digits or more, more preferably three digits or more.

(Step of Adjusting Concentration of Dyes and the Like in Coating Solution) Quantification is performed by the above method to determine the contents of the dye and the anti-fading agent in the coating waste liquid, and based on the values of these contents,
The content of the dye and the anti-fading agent in the regenerating coating solution is adjusted. The calculation of the liquid preparation formula is insufficient in order to fix the content of the dye, the anti-fading agent, and the solvent, and to adjust the concentration of the dye and the anti-fading agent in the initially adjusted coating solution. This is done by calculating the amount The concentration of the dye and the anti-fading agent is adjusted so that the concentration of the dye and the anti-fading agent in the regenerated coating solution matches the initially adjusted concentration of the dye and the anti-fading agent in the adjusted coating solution with a precision of two digits or more. As described above, in accordance with the above calculated values, the dye and the anti-fading agent are replenished in an insufficient amount and diluted with a solvent. For example, the initially adjusted concentrations of the dye and the anti-fading agent in the coating solution are 2.575% by weight and 0.257% by weight, respectively, and the concentrations of the dye and the anti-fading agent in the coating waste solution are respectively 6. In the case of 14% by weight and 0.256% by weight, the pigment contained in 200 g of the coating waste liquid is 12.2%.
84 g, and the anti-fading agent is 0.512 g. In order to add the other components (anti-fading agent and solvent) without adding a dye, and to make each component have the concentration in the initially adjusted coating solution, 0.714 g of the anti-fading agent and 276.
34g must be added exactly. It is preferable to add components other than the dye and the anti-fading agent with the same accuracy.

The reclaimed coating liquid of the present invention is a regenerated coating liquid regenerated by the above method. Further, the method for producing an optical information recording medium of the present invention is not particularly limited as long as the reproduction coating solution of the present invention is used in the step of forming the dye-containing recording layer, and the conventionally known spin coating method described above is used. The obtained optical information recording medium has good recording characteristics and can be used without any particular trouble.

[0041]

The present invention will be described below in more detail with reference to examples.

REFERENCE EXAMPLE In a SUS closed container, 2.65 parts of the indolenine dye (Compound A), 0.265 parts of the anti-fading agent (Compound B), 2,2,3,3-tetra 100 parts of fluoropropanol was mixed and dissolved using an ultrasonic vibrator (1800 W) for 2 hours to prepare a coating liquid for forming a recording layer. The pigment concentration in the coating solution is
The concentration was 2.575% by weight, and the concentration of the anti-fading agent was 0.257% by weight. After this coating solution was stored for half a day, a spiral pre-groove (track pitch: 1.6 μm, pre-groove width: 0.52 μ) was formed on the surface using the apparatus shown in FIG.
m, pregroove depth: 175 nm) polycarbonate substrate (diameter: 120 m) formed by injection molding
m, thickness: 1.2 mm, manufactured by Teijin Limited, trade name: Panlite AD5503), a nozzle made of stainless steel (inner diameter: 0.8 μm) on its pre-groove side surface
Using a conventional spin coater equipped with a coating liquid applying device having
The coating was performed while changing the speed from rpm to 4000 rpm to form a dye recording layer (thickness (in the groove): about 200 nm). During coating, the scattered coating liquid was collected in a waste liquid bottle through a drain. (Dye recording layer forming conditions) Atmospheric temperature, humidity: 23 ° C, 50% RH Coating liquid temperature: 23 ° C Substrate temperature: 23 ° C Exhaust air velocity: 0.8 m / sec

Then, Au was sputtered on the dye recording layer to form a reflective layer having a thickness of 150 nm. Further, using the spin coater used above, a UV-curable resin (trade name: SD-318, manufactured by Dainippon Ink and Chemicals, Inc.) was applied on the reflective layer at a rotation speed of the spinner head device of 30.
After coating while changing the speed from 0 rpm to 5000 rpm, the resin was cured by irradiating ultraviolet rays to form a protective layer having a thickness of 8 μm. Through the above steps, a CD-R type optical information recording medium comprising a substrate, a dye recording layer, a reflective layer and a protective layer was manufactured.

[Example 1] In the above reference example, 36.4 mg of the coating waste liquid collected in the waste liquid bottle was placed in a sample bottle.
Diluted with 3.0024 g of acetonitrile. On the other hand, 405.8 mg of the coating liquid for forming a recording layer of the reference example was placed in a sample bottle and diluted with 1.204 g of acetonitrile. This was measured using liquid chromatography under the following conditions, and the concentrations of the dye (compound A) and the anti-fading agent (compound B) were quantified by the absolute calibration curve method.

(Measurement conditions) Column: TSK-gel ODS-80Ts Column temperature: 25 ° C. Eluent: acetonitrile / water / acetic acid / triethylamine = 750/250/2/2 flow rate: 1 ml / min Pressure: 59 bar Detection wavelength: 254 nm Sample injection amount: 20 μm

The concentration of the dye in the waste liquid was 6.921%, and the concentration of the anti-fading agent was 1.139%. Based on this result, a solvent, a dye, and an anti-fading agent were added so that the dye concentration and the anti-fading agent concentration correspond to the above-mentioned coating solution and the dye concentration and the anti-fading agent concentration to two decimal places. The concentration was adjusted to obtain a regenerated coating solution. A CD-R type optical information recording medium comprising a substrate, a dye recording layer, a reflective layer, and a protective layer was produced in the same manner as in Reference Example, using the obtained reproduction coating solution.

[Evaluation] The optical information recording media of Examples and Reference Examples were evaluated for recording characteristics at an optimum power using “OMT-2000” manufactured by Pulstec. Table 2 shows the results
Shown in

[0048]

[Table 2]

As is clear from Table 2, the optical information recording medium produced by using the reproduction coating solution obtained by the reproduction method of the present invention is the optical information recording medium produced by using an unused adjusted coating solution. There was no significant difference in the recording characteristics, and it was found that the reclaimed coating liquid obtained by the regenerating method of the present invention could be used.

[0050]

By using the method for regenerating a coating liquid according to the present invention, in the step of forming a dye-containing recording layer in the method for manufacturing an optical information recording medium, the coating waste liquid is kept in a state containing a solvent and impurities. It can be used, and the manufacturing process can be significantly simplified by reducing the load on the recovery process. Also,
An optical information recording medium having good recording characteristics can be manufactured using the obtained reproduction coating liquid. Further, the manufacturing cost of the optical information recording medium can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a spin coater.

FIG. 2 is a schematic cross-sectional view of one side of an optical disc having a dye recording layer, a reflective layer, and a protective layer on a disc-shaped transparent resin substrate in this order.

FIG. 3 is a three-dimensional chart of liquid chromatography measured for a coating waste liquid.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Disc-shaped transparent resin substrate 2 Dye recording layer 3 Reflective layer 4 Protective layer 10 Spin coating device 11 Coating liquid application device 12 Nozzle 13 Spinner head device 14 Fixture 15 Shatter prevention wall 16 Opening 17 Drain 18 Exhaust device 19 Exhaust fan 40 Optical disk

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D075 AC64 AC84 AC99 BB99Z CA48 DA08 DB14 DC22 EA45 4F042 AA07 CC09 CC30 5D121 AA01 EE22 EE24 EE28 GG30

Claims (11)

[Claims] 1. A coating solution containing a dye and an anti-fading agent is dropped on the inner peripheral side of the surface of a disk-shaped transparent resin substrate horizontally held in a spin coater, and the coating solution is rotated by rotating the substrate. A step of casting the coating waste liquid on the outer peripheral side and discharging the excess coating liquid to the outside from the outer peripheral edge of the substrate, and collecting the coating waste liquid in a waste liquid collecting device. A step of quantifying the content, and a step of adjusting the concentration of the dye and the anti-fading agent in the coating waste liquid so as to match the concentration of the dye and the anti-fading agent in the coating liquid with two or more digits of accuracy, A method for regenerating a coating liquid for producing an optical information recording medium, comprising: 2. The method according to claim 1, wherein the dye is a dye represented by the following general formula (1). Embedded image General formula (1) (Wherein, R ^1, R ^2, and R ³ each independently represents a optionally substituted alkyl group, R ⁴ represents a methyl group, an ethyl group or a benzyl group. Further, R ² and optionally bonded to each other to form a ring and R ³ .X ^n-
Represents a divalent anion represented by the following general formula (2). ## STR2 ## Formula (2) (In the formula, R ^{5 to} R ¹⁰ each independently represent a hydrogen atom or an alkyl group which may have a substituent.) 3. The method for regenerating a coating solution according to claim 1, wherein the anti-fading agent is an anti-fading agent represented by the following general formula (3). Embedded image General formula (3) (In the formula, R ¹¹ and R ¹² each independently represent a hydrogen atom or a monovalent substituent.) 4. The method according to claim 1, wherein the amounts of the dye and the anti-fading agent in the coating waste liquid are determined by liquid chromatography.
4. The method for regenerating a coating solution according to any one of items 1 to 3. 5. The method for regenerating a coating solution according to claim 1, wherein the calibration accuracy in the liquid chromatography is three digits or more. 6. A coating solution containing a dye and an anti-fading agent is dropped on the inner peripheral side of the surface of a disk-shaped transparent resin substrate horizontally held in a spin coater, and the coating solution is rotated by rotating the substrate. At the same time, the excess coating liquid is discharged to the outside from the outer peripheral edge of the substrate, and the coating waste liquid is collected in a waste liquid collecting device. The content of the dye and the anti-fading agent in the coating waste liquid After reconciliation, the concentration of the dye and the anti-fading agent in the coating waste liquid is adjusted so as to match the concentration of the dye and the anti-fading agent in the coating solution with precision of two digits or more. 7. The reclaimed coating liquid according to claim 6, wherein the dye is a dye represented by the following general formula (1). Embedded image General formula (1) (Wherein, R ^1, R ^2, and R ³ each independently represents a optionally substituted alkyl group, R ⁴ represents a methyl group, an ethyl group or a benzyl group. Further, R ² and optionally bonded to each other to form a ring and R ³ .X ^n-
Represents a divalent anion represented by the following general formula (2). ## STR5 ## Formula (2) (In the formula, R ^{5 to} R ¹⁰ each independently represent a hydrogen atom or an alkyl group which may have a substituent.) 8. The reclaimed coating liquid according to claim 6, wherein the anti-fading agent is an anti-fading agent represented by the following general formula (3). Embedded image General formula (3) (In the formula, R ¹¹ and R ¹² each independently represent a hydrogen atom or a monovalent substituent.) 9. The method according to claim 6, wherein the amounts of the dye and the anti-fading agent in the coating waste liquid are determined by liquid chromatography.
9. The reclaimed coating liquid according to any one of items 1 to 8. 10. The reclaimed coating liquid according to claim 6, wherein the calibration accuracy in the liquid chromatography is three digits or more. 11. The reclaimed coating liquid according to claim 6 is dropped on the inner peripheral side of the surface of a disk-shaped transparent resin substrate horizontally held in a spin coater. The coating liquid is cast on the outer peripheral side by rotation of the substrate, and excess coating liquid is discharged outward from the outer peripheral edge of the substrate, and the coating waste liquid is collected by the waste liquid collecting device, and the coating film is dried. A method for producing an optical information recording medium, comprising the step of forming a dye-containing recording layer.