JP2000339776A - Production of optical information recording medium and optical information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an optical information recording medium which ensures few reading errors in reproduction and exhibits good recording and reproducing characteristics even when a solvent containing a fluorinated cyclic alkane or alkene is used as a solvent for preparing a coating solution for forming a dye layer. SOLUTION: When the optical information recording medium is produced through a step for forming a dye recording layer capable of recording information by irradiation with laser light by coating on a transparent discoid substrate, the dye recording layer is formed by adding a dye to a solvent containing a fluorinated cyclic alkane or alkene, keeping the dye-solvent mixture in the temperature range from 45 deg.C to (the boiling point of the solvent)-5 deg.C for 5 min to 2 hr, coating the top of the substrate with the resulting coating solution and carrying out drying. The fluorinated cyclic alkane is preferably 1,1,2,2,3,3,4- heptafluorocyclopentane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical information recording medium, which includes a step of forming a dye recording layer capable of recording information by irradiating a laser beam on a transparent disk-shaped substrate. It relates to a recording medium.

[0002]

2. Description of the Related Art An optical information recording medium (write-once type optical disk) in which information can be recorded only once by a laser beam.
Is known as a write-once CD (so-called CD-R).
A typical structure of a CD-R type optical disk is such that a recording layer made of an organic dye, a reflective layer made of a metal such as gold, and a protective layer made of a resin are further laminated in this order on a transparent disk-shaped substrate. . Writing (recording) of information on this CD-R type optical disk is generally performed by using a near infrared laser beam (usually 7
The irradiation is performed by irradiating the optical disk with laser light having a wavelength of about 80 nm, and the irradiated portion of the dye recording layer absorbs the light and locally rises in temperature, causing a physical or chemical change (for example, a pit or the like). Is produced by changing its optical properties. On the other hand, reading (reproduction) of information is also usually performed by irradiating the optical disc with laser light having the same wavelength as the recording laser light, and the portion where the optical characteristics of the dye recording layer has changed (recording by forming pits or the like) This is performed by detecting a difference in reflectance between a portion (unchanged portion) and a portion that does not change (unrecorded portion).

Recently, there has been a demand for an optical information recording medium having a larger recording capacity, and a write-once DVD (digital video disk) (DVD-R) has been proposed to meet this demand. (For example, "Nikkei New Media" separate volume "DVD", published in 1995).
According to this document, a guide groove (pre-groove) for tracking a laser beam to be irradiated is provided as a write-once DVD-R type optical disk corresponding to the CD-R type optical disk as compared with the CD-R type optical disk. Less than half (0.74-0.
8 μm) on a transparent disk-shaped substrate formed as narrow as 8 μm), and a recording layer made of an organic dye, and two laminated bodies usually provided with a metal reflective layer and a resin protective layer on the recording layer. A structure in which the recording layer is attached to the inside with an adhesive, or a laminated body composed of two sheets, one of which is replaced with a disc-shaped protective plate, and the recording layer is formed only on one substrate, It describes a configuration in which a metal reflective layer and a protective layer made of resin are sequentially provided. Writing (recording) and reading (playback) of information on the DVD-R type optical disc described above
Is a laser beam having a wavelength shorter than 780 nm (usually 600 to 780 nm) generally used for the CD-R type optical disc.
The irradiation is performed by irradiating laser light having a wavelength of 700 nm.

In the formation of the dye recording layer of the CD-R type or DVD-R type optical disk, generally, a coating solution in which a dye is dissolved in a solvent is prepared, and the coating solution is applied by spin coating. It is done by doing. In the spin coating method, the surplus coating solution is shaken off at the edge of the substrate while the coating solution dropped on the substrate is cast toward the outer peripheral side by the rotation of the substrate, and at the same time, the solvent in the coating solution evaporates. Then, by drying, a dye recording layer having a thin and uniform thickness is formed on the substrate.

[0005] Solvents for preparing a dye-containing coating solution include:
Conventionally, fluorine-containing compounds have been preferably used, for example, as described in JP-A-63-159090. This fluorine-containing compound has relatively high solubility in a dye and has excellent properties such as not dissolving a polycarbonate substrate. The above-mentioned publication specifically describes fluorinated alcohols (2,
An example using 2,3,3-tetrafluoro-1-propanol) is described. Since this solvent has a relatively low flash point (47.5 ° C.), preparation of the coating solution is usually carried out by dissolving the dye in the above-mentioned solvent at around room temperature (25 ° C.).

JP-A-10-316596, 10-3
JP-A-16597 and JP-A-10-316598 propose fluorinated saturated hydrocarbons which are mainly useful as detergents. In this publication, a 4- to 6-membered fluorinated cyclic alkane or alkene is preferable as the fluorinated saturated hydrocarbon, and in particular, 1,1,2,2,2
There is a description that 3,3,4-heptafluorocyclopentane is preferable.

[0007]

SUMMARY OF THE INVENTION The inventor has set forth the above-mentioned fluorinated cyclic alkanes or alkenes, especially 1,1,2,2.
2,3,3,4-heptafluorocyclopentane is advantageous in that it can be obtained relatively inexpensively and can be used safely. Therefore, a solvent containing these compounds is prepared by preparing a coating solution for forming a dye recording layer. It was studied to use it as a solvent for cleaning. According to that study, the solvent containing this compound is:
The solubility in the dye is lower than that of the above-mentioned fluorinated alcohol. Therefore, when the coating solution is prepared using this solvent and the dye recording layer is formed by the spin coating method, the obtained optical disc has good recording and reproduction. It has been found that there is a problem that characteristics, particularly good jitter, cannot be obtained, and thus errors are likely to occur in the reproduced signal.

It is an object of the present invention to provide good jitter even when a solvent containing the above-mentioned fluorinated cyclic alkane or alkene is used as a solvent for preparing a coating solution for forming a dye recording layer. An object of the present invention is to provide a method for manufacturing an optical information recording medium that exhibits few recording and reproducing characteristics.

[0009]

According to the study of the present inventors, a dye recording layer was formed by preparing a coating solution using a solvent containing a fluorinated cyclic alkane or alkene under the same conditions as the above-mentioned fluorinated alcohol. In such a case, the dye is not sufficiently dissolved and nuclei are likely to remain, so that the formed dye recording layer becomes non-uniform at a fine level. It was found that when a signal was recorded, the length of the pit was shifted, and the jitter was likely to deteriorate. According to a further study of the present inventors, when preparing a coating solution using a solvent containing a fluorinated cyclic alkane or alkene, by maintaining a mixture of the dye and the solvent at a specific high temperature region for a predetermined time, A coating solution that improves the solubility of the dye and hardly generates nuclei can be prepared. By using this coating solution, a dye recording layer with a uniform layer at a fine level can be formed. It has been found possible. Therefore, when a signal by a laser beam is recorded on such a layer, pits are faithfully formed with respect to the recording signal, and an optical information recording medium showing good jitter can be obtained.

The present invention relates to a method for manufacturing an optical information recording medium, which comprises a step of coating and forming a dye recording layer capable of recording information by irradiating a laser beam on a transparent disk-shaped substrate. Is added to a solvent containing a fluorinated cyclic alkane or alkene to obtain a dye-solvent mixture, and the mixture is heated at a temperature of 45 ° C. or more and a boiling point of the solvent of 5 ° C. or less for 5 minutes to A method for producing an optical information recording medium is characterized in that a coating solution is prepared by maintaining the coating solution for 2 hours, and then the coating solution is applied on a substrate and dried.

According to the study of the present inventor, when a coating solution for forming a dye recording layer is applied on a substrate, the concentration of the coating solution progresses as the solvent evaporates, causing a kind of supersaturation. Furthermore,
It is considered that the dye in the coating solution goes through a transient state that is neither undissolved nor completely dissolved, and eventually forms a solid film of the dye in an amorphous state. For this reason, if a transient dye (crystal or aggregation nucleus) that is neither undissolved nor completely dissolved is present in the coating solution, fine crystals and aggregates will be formed in the supersaturated state. Easy to generate. Then, these fine crystals and agglomerated parts create a non-uniform state of the dye during the drying process, and when a layer is formed, the film becomes non-uniform at a fine level. By utilizing the method for preparing a coating solution according to the present invention, the dye serving as a nucleus of the crystals or aggregation is completely dissolved, so that fine crystals or aggregation portions are not generated or the generation thereof is suppressed. It is thought that. Therefore, when a dye recording layer is formed with such a coating liquid, it becomes possible to form a very uniform dye recording layer.

Further, the present invention relates to an optical information recording medium provided with a dye recording layer capable of recording information by irradiating a laser beam on a transparent disc-shaped substrate, wherein the dye recording layer is a fluorinated cyclic alkane. Alternatively, a coating solution prepared by maintaining a dye / solvent mixture obtained by adding a dye to a solvent containing an alkene at a temperature of 45 ° C. or higher and a boiling point of the solvent of 5 ° C. or lower for 5 minutes to 2 hours. There is also an optical information recording medium characterized by being formed by using the optical information recording medium.

The method for manufacturing an optical information recording medium of the present invention preferably has the following aspects. (1) Optical information recording in which a fluorinated cyclic alkane or alkene is contained in a solvent in a capacity of 60% or more (more preferably 80% or more, particularly preferably 90% or more, and most preferably 100%). The method of manufacturing the medium. (2) As a fluorinated cyclic alkane or alkene,
A method for producing an optical information recording medium using 1,1,2,2,3,3,4-heptafluorocyclopentane.

(3) Preparation of the coating solution is carried out at 50 ° C. or higher (more preferably at 55 ° C. or higher, particularly preferably at 60 ° C. or higher).
Of producing an optical information recording medium at a temperature of (4) A method for producing an optical information recording medium, wherein the preparation of the coating solution is performed at a temperature of 10 ° C. or lower (more preferably 15 ° C. or lower, particularly preferably 20 ° C. or lower) of the boiling point of the solvent. (5) The mixture is at least 45 ° C and the boiling point of the solvent is 5 ° C.
Time to maintain in the following temperature range: 10 minutes to 1 hour 30
Minutes (more preferably, 15 minutes to 1 hour and 15 minutes). (6) The mixture is heated to 45 ° C. or higher and the boiling point of the solvent is 5 ° C.
A method for producing an optical information recording medium, wherein an operation of maintaining the mixture in the following temperature range for 5 minutes to 2 hours is performed while applying ultrasonic waves to the mixture. (7) The coating of the coating solution on the substrate is carried out at 40 ° C. or less (more preferably at 35 ° C. or less, particularly preferably at 25 ° C. to 30 ° C.).
(In the range of ° C.). (8) A method for producing an optical information recording medium in which the dye recording layer is formed by spin coating. (9) A dye solution using a cyanine dye, an azo dye, or an oxonol dye as the dye. (10) The optical information recording medium has a configuration in which a dye recording layer, a metal reflective layer, and a resin protective layer are provided in this order on a transparent disk substrate.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the method for producing an optical information recording medium of the present invention, a dye recording layer is formed by the steps of preparing a dye / solvent mixture by adding a dye to a solvent containing a fluorinated cyclic alkane or alkene. A step of preparing a coating solution by maintaining the mixture at a temperature of 45 ° C. or higher and a temperature range of 5 ° C. or lower of the boiling point of the solvent for 5 minutes to 2 hours, and then applying the prepared coating solution on a substrate. It is performed by a method including a step of coating and drying.

The optical information recording medium manufactured according to the manufacturing method of the present invention includes a CD-R type optical disk and a DV having a dye recording layer formed by the characteristic method as described above.
A DR optical disk is included. In this specification, CD
A method for manufacturing an optical information recording medium according to the present invention will be described using an R-type optical disk as an example.

A typical example of a CD-R type optical disk is manufactured by laminating a dye recording layer, a metal reflective layer, and a resin protective layer in this order on a transparent disk-shaped substrate. Hereinafter, a method for manufacturing an optical information recording medium including a transparent substrate, a dye recording layer, a metal reflective layer, and a resin protective layer will be sequentially described by way of example.

The transparent substrate can be arbitrarily selected from various materials used as a substrate of a conventional optical information recording medium. Examples of the substrate material 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 may be used together if desired. Note that these materials can be used in the form of a film or a rigid substrate. Among the above materials, polycarbonate is preferred from the viewpoints of moisture resistance, dimensional stability, cost, and the like.

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 adhesion, and preventing deterioration of the recording layer. Examples of the material of the undercoat layer include polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleic anhydride copolymer, polyvinyl alcohol, N-methylol acrylamide, styrene / vinyl toluene copolymer, and chlorosulfonation. Polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate-vinyl chloride copolymer, ethylene
Vinyl acetate copolymer, polyethylene, polypropylene,
Examples include polymeric substances such as polycarbonate; and surface modifiers such as silane coupling agents.

The undercoat layer is prepared by dissolving or dispersing the above substances in an appropriate solvent to prepare a coating solution, and then applying this coating solution to the substrate surface by 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.
-20 μm, preferably 0.01-10 μm
m.

On the substrate (or undercoat layer), it is preferable to form tracking grooves or irregularities (pre-grooves) representing information such as address signals. This pregroove is preferably formed directly on the substrate when injection molding or extrusion molding of a resin material such as polycarbonate.

The pre-groove may be formed by providing a pre-groove layer. As a material for the pregroove layer, a mixture of at least one monomer (or oligomer) of acrylic acid monoester, diester, triester and tetraester and a photopolymerization initiator can be used. The formation of the pre-groove layer is performed, for example, by first forming a precisely formed master (stamper).
A mixture of the above-mentioned acrylate and the polymerization initiator is applied thereon, and after further placing the substrate on the coating solution layer, the coating layer is cured by irradiating ultraviolet rays through the substrate or the matrix. To fix the substrate and the coating layer.
Next, it can be obtained by peeling the substrate from the matrix. The thickness of the pre-groove layer is generally 0.05 to 1
It is in the range of 00 μm, preferably in the range of 0.1 to 50 μm.

The depth of the pregroove is 0.01 to 0.3 μm
m is preferable, and the half width is
It is preferably in the range of 0.2 to 0.9 μm. By setting the depth of the pre-groove in the range of 0.15 to 0.2 μm, the sensitivity can be improved without substantially lowering the reflectance, which is particularly preferable. Therefore, such an optical disk (an optical disk having a dye recording layer and a metal reflective layer formed on a deep groove substrate) has high sensitivity, so that it is possible to perform recording even with a low laser power. It has advantages that it can be used or that the service life of a semiconductor laser can be extended.

A dye recording layer is provided on the substrate. The dye used for forming the dye recording layer is not particularly limited. For example, cyanine dyes, phthalocyanine dyes, imidazoquinoxaline dyes, pyrylium / thiopyrylium dyes, azulenium dyes, squalilium dyes,
Metal complex dyes such as Ni and Cr, naphthoquinone dyes, anthraquinone dyes, indophenol dyes,
Examples include merocyanine dyes, oxonol dyes, naphthoaniline dyes, triphenylmethane dyes, triallylmethane dyes, aminium / diimmonium dyes, and nitroso compounds. Among these dyes, cyanine dyes, phthalocyanine dyes, azo dyes, azurenium dyes, squalilium dyes, oxonol dyes and imidazoquinoxaline dyes are preferred. Particularly preferred are cyanine dyes, azo dyes, and oxonol dyes.

The cyanine dye is preferably a compound represented by the following general formula (II). The general formula (II)
The cyanine dyes represented by
188, 10-151861, and 1
No. 1-58973.

[0026]

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In the above general formula (II), Z ¹ and Z
² independently represents an atomic group necessary for forming a 5- or 6-membered nitrogen-containing heterocyclic ring; R ¹ and R ² each independently represent an alkyl group; L ¹ and L ² , L ³ , L ⁴ and L ⁵
Each independently represents a methine group which may be substituted; n1 and n2 each independently represent 0, 1 or 2; p and q each independently represent 0 or 1;
Represents a charge neutralizing counter ion, and m1 represents a number of 0 or more necessary to neutralize the charge in the molecule.

The cyanine dye represented by the general formula (II) is preferably a compound represented by the following general formula (II-1) or (II-2).

[0029]

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The above general formula (II-1) and general formula (II-
In 2), Z ³ and Z ⁴ each independently represent an atomic group necessary for forming an optionally substituted benzene ring or naphthalene ring, and R ³ , R ⁴ , R ⁵ , R ⁶ ,
R ⁷ and R ⁸ each independently represent an alkyl group having 1 to 8 carbon atoms, and R ⁹ represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aralkyl group having 7 to 10 carbon atoms. An aryl group having 6 to 10 carbon atoms, 1 carbon atom
Represents an alkoxy group, a heterocyclic group, a halogen atom, or a carbamoyl group having 1 to 8 carbon atoms,
^m2- represents an anion, and m2 represents 1 or 2.

The azo dye is preferably a compound represented by the following general formula (III).

[0032]

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In the above general formula (III), M represents a metal atom, and X represents an oxygen atom, a sulfur atom, or ＮＲNR ¹¹
R ¹¹ represents a hydrogen atom, an alkyl group, an aryl group,
Represents an acyl group, an alkylsulfonyl group, or an arylsulfonyl group, Z ¹¹ represents an atomic group necessary for forming a 5- or 6-membered nitrogen-containing heterocyclic ring, and Z ¹² represents an aromatic ring or a heterocyclic ring. Represents the atomic groups required to complete the aromatic ring.

The azo dye represented by the general formula (III) is preferably a compound represented by the following general formula (III-1).

[0035]

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In the above general formula (III-1), M is
Represents iron, cobalt, nickel, copper, zinc, palladium, platinum, or gold, and Y represents an oxygen atom, a sulfur atom, or =
Represents ^{NR 12, R 12, R 13} , and R ¹⁴ are each independently
Represents an alkyl group which may have a substituent having 1 to 12 carbon atoms, wherein R ¹³ and R ¹⁴ may be linked to each other to form a ring, and R ¹⁵ may have 1 to 12 carbon atoms. An alkyl group which may have a substituent or a carbon atom having 6 to 1 carbon atoms
6 represents a phenyl group which may have a substituent or a naphthyl group, wherein R ¹⁶ and R ¹⁷ each independently represent a hydrogen atom,
Represents a halogen atom, an alkyl group, an aryl group, a cyano group, an acyl group, an alkylsulfonyl group, or an arylsulfonyl group, and R ¹⁸ , R ¹⁹ , and R ²⁰ each independently represent a hydrogen atom, an alkyl group, an aryl group, Represents a hydroxy group, an alkoxy group, an aryloxy group, an amino group, a carbonamide group, a sulfonamide group, a cyano group, a halogen atom, an acyl group, an alkylsulfonyl group, or an arylsulfonyl group.

The oxonol dye has the following general formula (IV-
The compound represented by 1) or the general formula (IV-2) is preferable. In addition, the general formula (IV-1) or the general formula (IV-
The compound represented by 2) is described in, for example, JP-A-10-297.
No. 103, No. 10-309871 and No. 1
No. 0-309872.

[0038]

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The formula (IV-1) or (IV-
In 2), A ²¹ , A ²² , B ²¹ and B ²² each independently represent a substituent, and Y ²¹ and Z ²¹ each independently represent an atom required for forming a carbocyclic or heterocyclic ring. And E and G each independently represent an atomic group necessary for completing a conjugated double bond chain, and X ²¹ represents ＝ O, ＮＲNR ²¹
Or = represents C (CN) _2, X ²² is, -O, represents -NR ²¹ or -C (CN) ₂ (where, R ²¹ represents a ^{substituent), L 21, L 22,} L 23, L ²⁴ and L ²⁵ each independently represent a methine group which may be substituted; V ^{k +} represents a cation; n3 and n4 each independently represent 0, 1 or 2; , Each independently represents 0 or 1,
K represents an integer of 1 to 10.

The dye recording layer is formed by (1) a step of adding a dye to a solvent containing a fluorinated cyclic alkane or an alkene to prepare a mixture of the dye and the solvent, and (2) a step of preparing the obtained mixture at 45 ° C. or more. And a step of preparing a coating solution by maintaining the solvent in a temperature range of 5 ° C. or lower for 5 minutes to 2 hours, and then (3) coating the coating solution on a substrate.
This is performed by a method including a drying step. The process will be described below in the order of steps.

(1) A dye is added to the solvent containing the fluorinated cyclic alkane or alkene to prepare a mixture of the dye and the solvent. The fluorinated cyclic alkane or alkene is preferably a 4- to 6-membered fluorinated cyclic alkane or alkene, more preferably a 5-membered fluorinated cyclic alkane or alkene. The fluorinated cyclic alkane or alkene is 0.5 to 2.0 times the number of carbon atoms in the skeleton (more preferably 1.0 to 2.0 times the number of carbon atoms, particularly preferably 1.0 to 1. It is preferably a fluorinated cyclic alkane or alkene substituted by 8 times, most preferably 1.2 to 1.6 times) fluorine atoms. Specific examples of the fluorinated cyclic alkane include 1,1,2,2,3-pentafluorocyclobutane, 1,1,2,2,3,3-hexafluorocyclopentane, 1,1,2,2,3 , 3,4-heptafluorocyclopentane, 1,1,2,2,3,4,5-heptafluorocyclopentane, 1,1,2,2,3,3
4,4-octafluorocyclopentane, 1,1,2,
2,3,3,4,5-octafluorocyclopentane,
And 1,1,2,2,3,3,4,4,5-nonafluorocyclohexane. Specific examples of the fluorinated cyclic alkene include 1,1,2,2,
3,4-hexafluorocyclobutene, 1,1,2,2
2,3,3,4,5-octafluorocyclopentene,
And 1,1,2,2,3,3,4,4,5,6-decafluorocyclohexene. In addition, these compounds are described in the above-mentioned JP-A-10-316596.
No. 10-316597 and No. 10-31659
No. 8 and JP-A Nos. 8-122603 and 8-1
No. 43487 and No. 9-95458.

In the present invention, the fluorinated cyclic alkane or alkene may be 1,1,2,2,3,3,4-
Heptafluorocyclopentane, 1,1,2,2,3
4,5-heptafluorocyclopentane, 1,1,2,2
2,3,3,4,4-octafluorocyclopentane,
And 1,1,2,2,3,3,4,5-octafluorocyclopentane. 1,1,2,
It is particularly preferable to use 2,3,3,4-heptafluorocyclopentane (a compound represented by the following formula).

[0043]

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The fluorinated cyclic alkane or alkene is contained in the solvent in an amount of 60% or more (more preferably, the temperature is 80% or more, particularly preferably 90% or more, and most preferably 10% or more.
(0%). The mixture of the dye and the solvent is preferably prepared by first adding the dye to the solvent at normal temperature (25 ° C.), and then increasing the temperature according to step (2).

(2) The obtained mixture is maintained in a temperature range of 45 ° C. or higher and a boiling point of the solvent of 5 ° C. or lower for 5 minutes to 2 hours to prepare a coating solution. The obtained mixture is preferably at least 50 ° C. (more preferably at least 55 ° C., particularly preferably at least 60 ° C.), and the boiling point of the solvent is preferably 1 or more.
The temperature is maintained at 0 ° C. or lower (more preferably 15 ° C. or lower, particularly preferably 20 ° C. or lower). If the temperature is too high, the pigment will be degraded or the solvent will be easily evaporated in large quantities. The time maintained in the above temperature range is preferably 10 minutes to 1 hour and 30 minutes, more preferably 1 minute.
It is preferable to be 5 minutes to 1 hour and 15 minutes. During this time, the dye is sufficiently dissolved, and a coating liquid in which nucleation is almost suppressed can be obtained. If the maintenance time is less than 5 minutes, the dye is not sufficiently dissolved, and if it exceeds 2 hours,
Inconveniences such as deterioration of the dye are likely to occur.

In preparing the coating solution, it is preferable to perform the operation of maintaining the temperature at the above-mentioned temperature using a suitable stirring / vibration means in order to accelerate the dissolution of the dye. Examples of such stirring / vibration means include a means using ultrasonic waves and a magnetic stirrer. It is preferable to use an ultrasonic means. Further, in order to prevent excessive evaporation of the solvent, it is preferable to prepare the coating liquid using a container having a lid. For example, it is ideal to use a container having a lid capable of withstanding a pressure increase (eg, a pressure container). However, there is a problem that the pressure vessel is generally dangerous and difficult to handle. Therefore, it is preferable to use a container with a lid having a hole for vapor release. In such a case, in order to suppress the amount of evaporation, it is preferable to take measures to reduce the area of the liquid surface by using a vertical container or the like. For example, it is preferable to use a container having a shape having a smaller diameter at the top. Further, at high temperatures, the pigment is liable to change in quality. Particularly, in the presence of oxygen, the composition is liable to be deteriorated. Therefore, a measure may be taken to minimize the oxygen concentration in the air in contact with the coating liquid. When such a method is introduced, the oxygen concentration in the air in contact with the coating solution is 1
It is preferably at most 5%, more preferably 10%
Or less, particularly preferably 5% or less, most preferably 1%
It is as follows.

The concentration of the coating solution is preferably maintained at a predetermined concentration in order to affect the coating characteristics. For this reason,
For example, it is preferable to measure the evaporation amount of the solvent and add the evaporated amount of the solvent during preparation of the coating solution. The addition of the solvent is preferably performed in a plurality of times. When the replenishment of the solvent is performed a plurality of times, it is preferable that the replenishment of the solvent is performed at a constant liquid temperature. Preferably, the addition of the evaporated solvent is carried out at a temperature near normal temperature (20 to 30 ° C.,
More preferably, it is performed after the temperature reaches 22 to 28 ° C). If the amount of evaporation of the solvent is too large, the concentration of the coating solution proceeds excessively, causing nucleation of the dye. Therefore, the amount of evaporation of the solvent is preferably 30% or less of the liquid volume of the first coating solution, more preferably. Is preferably controlled to 20% or less, particularly preferably 10% or less.

When a fluorinated cyclic alkane or alkene and another solvent are used for preparing a coating solution, a mixture obtained by adding a dye to the fluorinated cyclic alkane or alkene is dissolved at a high temperature, and then the solution is added to the solution. It is preferable to prepare a coating solution by a method of adding another solvent. For example, there is a method of adding a dye to a mixed solvent composed of a plurality of solvents including a fluorinated cyclic alkane or an alkene, and dissolving the dye at a high temperature to prepare a coating solution. This is not a preferred method because it becomes difficult to determine which solvent has evaporated and how much, and the mixing ratio of the solvent initially set changes, making it difficult to adjust the final dye concentration.

Examples of solvents other than fluorinated cyclic alkanes or alkenes include esters such as butyl acetate and cellosolve acetate; ketones such as methyl ethyl ketone, cyclohexanone and methyl isobutyl ketone; chlorinations such as dichloromethane, 1,2-dichloroethane and chloroform. Hydrocarbons; amides such as dimethylformamide; hydrocarbons such as cyclohexane; ethers such as tetrahydrofuran, ethyl ether and dioxane; alcohols such as ethanol, n-propanol, isopropanol, n-butanol and diacetone alcohol;
2,2,3,3-tetrafluoro-1-propanol,
Fluorinated solvents such as 2,2,3,3-tetrafluoro-1-pentanol; 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. The coating solution further contains an antioxidant, U
Various additives such as a V absorbent, a plasticizer, and a lubricant may be added according to the purpose.

When adjusting the coating solution, a discoloration inhibitor,
If desired, a binder can be added. Representative examples of anti-fading agents include nitroso compounds, metal complexes,
Examples thereof include diimmonium salts and aminium salts. These examples are described in JP-A-2-300288 and JP-A-3-300288.
No. 224793 or No. 4-146189. When the anti-fading agent is used in combination, the amount of the anti-fading agent is usually 0.1 to 5 based on the amount of the dye.
It is in the range of 0% by weight, preferably in the range of 0.5 to 45% by weight, more preferably in the range of 3 to 40% by weight, especially in the range of 5 to 25% by weight.

Examples of the binder include, for example, gelatin,
Natural organic high molecular substances such as cellulose derivatives, dextran, rosin and rubber; and hydrocarbon resins such as polyethylene, polypropylene, polystyrene and polyisobutylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl chloride / polyvinyl acetate copolymer Vinyl resin such as polymethyl acrylate, acrylic resin such as polymethyl methacrylate, polyvinyl alcohol, chlorinated polyethylene, epoxy resin, butyral resin, rubber derivative, initial condensate of thermosetting resin such as phenol / formaldehyde resin And other synthetic organic polymers. When a binder is used as a material for the dye recording layer, the upper limit of the amount of the binder used should be 20 parts by weight, preferably 10 parts by weight, more preferably 5 parts by weight, based on 100 parts by weight of the dye. It is.

The concentration of the dye in the coating solution for the dye recording layer thus prepared is generally in the range of 0.01 to 10% by weight, preferably in the range of 0.1 to 5% by weight.

(3) The coating liquid obtained above is coated on a substrate and dried. The application of the coating solution prepared as described above on the substrate, the temperature of the coating solution is 40 ℃ or less, more preferably,
It is preferably carried out at a temperature of 35 ° C. or lower, particularly preferably in the range of 25 ° C. to 30 ° C. Spray method, spin coating method, dip method, roll coating method,
Although a blade coating method, a doctor roll method, a screen printing method, and the like can be used, in the present invention, it is preferable to use a spin coating method. The dye recording layer may be a single layer or a multilayer. The thickness of the dye recording layer (the thickness after drying) is generally in the range of 20 to 500 nm, preferably in the range of 50 to 300 nm.

It is preferable that a metal reflective layer is provided on the dye recording layer, particularly for the purpose of improving the reflectivity when information is reproduced. The light-reflective substance that is the material of the metal reflection layer is a substance having a high reflectance with respect to laser light, and examples thereof include Mg, Se, Y, Ti, Zr, Hf, V, and N.
b, Ta, Cr, Mo, W, Mn, Re, Fe, Co,
Ni, Ru, Rh, Pd, Ir, Pt, Cu, Ag, A
u, Zn, Cd, Al, Ga, In, Si, Ge, T
e, Pb, Po, Sn, Bi, and other metals and semi-metals or stainless steel. These substances may be used alone, or in combination of two or more kinds, or may be used as an alloy. Of these, preferred are Cr, Ni, Pt, Cu, Ag, Au,
Al and stainless steel. Particularly preferred are Au metal, Ag metal, and alloys thereof. Preferred Au or Ag alloys include alloys containing at least one metal selected from the group consisting of Pt, Cu, and Al, respectively. Most preferably, it is Ag metal or Ag alloy. The metal reflective layer can be formed on the dye recording layer by, for example, vapor deposition, sputtering, or ion plating of a light reflective substance. The thickness of the metal reflective layer is generally from 10 to 800.
nm, preferably in the range of 20 to 500 nm, more preferably in the range of 50 to 300 nm.

Usually, a resin protective layer is provided on the metal reflective layer for the purpose of physically and chemically protecting the dye recording layer and the metal reflective layer. Examples of the material used for the protective layer include SiO, SiO ₂ , MgF ₂ , SnO ₂ , and Si ₃ N.
_And organic substances such as thermoplastic resins, thermosetting resins, and UV curable resins. The protective layer can be formed, for example, by laminating a film obtained by extrusion of a plastic on a metal reflective layer and / or a substrate via an adhesive. Alternatively, it may be provided by a method such as vacuum deposition, sputtering, or coating. In the case of a thermoplastic resin or a thermosetting resin, they can also be formed by dissolving these in an appropriate solvent to prepare a coating solution, applying the coating solution, and drying. In the case of a UV curable resin, it is also formed without using a solvent or by dissolving in a suitable solvent to prepare a coating solution, applying the coating solution, and irradiating with UV light to cure the resin. be able to. Various additives such as an antistatic agent, an antioxidant, and a UV absorber may be added to these coating solutions according to the purpose. This resin 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 moisture resistance. In the present invention, it is preferable that a resin protective layer is provided. The thickness of the resin protective layer is generally 0.
It is in the range of 1 to 100 μm.

The recording and reproduction of optical information using a CD-R type optical disk is performed, for example, as follows. In the case of a CD-R type optical disk, recording and reproduction can be performed at 1 × speed (1.2 to 1.4 m / sec) of a normal CD format, and 2 ×, 4 ×, 6 ×, or Recording and reproduction at higher speeds are possible. The optical disk is set to a predetermined constant linear speed (1.2 to 1.4 in the case of the CD format).
(m / sec) or a predetermined constant angular velocity while irradiating recording light such as semiconductor laser light from the substrate side.
By this light irradiation, the irradiated portion of the recording layer absorbs the light and locally raises the temperature, and pits are generated to record information by changing its optical characteristics. As the recording light, a semiconductor laser beam having an oscillation wavelength in the range of 500 to 850 nm is used. The wavelength of the laser beam used is preferably in the range from 500 to 800 nm. In the case of a CD-R type optical disk, 770 to 79
Wavelengths in the range of 0 nm are suitable. Reproduction of the information recorded as described above can be performed by irradiating the semiconductor laser light from the substrate side while rotating the optical disk at a predetermined constant linear speed, and detecting the reflected light.

Although the above description has been given of the method of manufacturing the optical information recording medium of the present invention by taking the method of manufacturing a CD-R type optical disk as an example, the DVD-R type optical disk is manufactured in the same manner. Can be manufactured.

[0058]

EXAMPLES Examples of the present invention and comparative examples will be described below. [Example 1]

[0059]

Embedded image

A container with a lid having a hole for steam release,
A coating liquid for forming a recording layer was prepared by the following method using a container having a small diameter above the container. That is, 1.5 g of the indolenine-based cyanine dye and 1,
100 mL of 1,2,2,3,3,4-heptafluorocyclopentane (trade name: Zeorola H, boiling point: 82.5 ° C., manufactured by Zeon Corporation) was introduced at room temperature (25 ° C.), Next, the temperature was raised to 60 ° C. over 10 minutes, and in this state, ultrasonic waves were applied for 1 hour to dissolve, thereby preparing a coating solution for forming a recording layer.

The temperature of the coating solution was lowered to 25 ° C., and a spiral pre-groove (track pitch: 1.6 μm, pre-groove width: 500 nm, pre-groove depth: 175 nm) was formed on the surface by injection molding. Formed polycarbonate substrate (outer diameter: 120 mm, inner diameter: 1
A dye recording layer (thickness (within the pre-groove): 180 nm) was formed on the pre-groove side surface (5 mm, thickness: 1.2 mm) by spin coating and dried.

Next, silver was sputtered on the dye recording layer using a DC magnetron sputtering apparatus to obtain a film thickness of about 150 n.
m of metal reflective layers were formed. Further, U
V-curable resin (trade name: DAICURE CLEAR SD-31)
8, manufactured by Dainippon Ink and Chemicals, Inc.) by spin coating, followed by irradiating ultraviolet rays with a metal halide lamp and curing to form a resin protective layer having a thickness of about 8 μm.

According to the above steps, a CD-R type optical disk (hereinafter simply referred to as a CD-R) according to the present invention in which a substrate, a dye recording layer, a metal reflective layer, and a resin protective layer are laminated in this order.
R) was prepared.

Comparative Example 1 In Example 1, the same amount of the indolenine-based cyanine dye was added to the same amount of 1,1,2,2
3,3,4-heptafluorocyclopentane at room temperature (2
CD-R for comparison was prepared in the same manner except that a coating solution for forming a dye recording layer was prepared without application of ultrasonic waves and maintained in that state for one hour. Manufactured.

[Evaluation as Optical Information Recording Medium] A laser beam having a wavelength of 780 nm was applied to the optical disks of Examples and Comparative Examples by using OMT2000 (manufactured by Pulstec) with NA0.
5 with a constant linear speed of 4.8 m / sec.
The FM signal was recorded at the optimum recording power while changing the recording power from 3 to 10 mW. After that, CD-CATS
Wavelength 7 using (Audio Development Co., Ltd.)
A 80-nm laser beam was read out using a 0.45 NA pickup with a constant linear velocity of 1.2 m / sec and a laser power of 0.5 mW, and 11T land jitter (pit-to-pit jitter) at a position 40 mm from the center of the substrate. ) To T
It measured using IA (made by Hewlett Packard). The smaller the jitter value, the more uniform the recording signal. Table 1 shows the evaluation results.

[0066]

[Table 1] Table 1 {11T land jitter (ns)} ── Example 1 31 Comparative Example 1 37 ────────────────────

From the results shown in Table 1, the dyes were 1, 1, 2, 2,
When a coating solution was prepared by adding to a solvent composed of 3,3,4-heptafluorocyclopentane and dissolving in a specific high temperature range for a predetermined time according to the present invention (Example 1),
Since the dye is sufficiently dissolved and the coating liquid is hardly generated as a dye serving as a crystal nucleus, a uniform dye recording layer in an amorphous state can be formed. Therefore, it can be seen that the pits are formed relatively faithfully with respect to the recording signal by the laser beam, so that an optical disc exhibiting good jitter can be manufactured. On the other hand, when the coating solution was prepared at a temperature around room temperature (25 ° C.) as in Comparative Example 1, the dye was not sufficiently dissolved, and thus the nuclei remained in the coating solution. For this reason, when a dye recording layer is formed using this coating solution, it is considered that the recording layer has a non-uniform film at a fine level due to the nucleus, and the recording layer is insensitive to a recording signal by a laser beam. As a result, it can be seen that pits are formed with a shift and jitter is deteriorated.

[0068]

According to the present invention, when a fluorinated cyclic alkane or alkene is used as a solvent for preparing a coating liquid for forming a dye recording layer, the preparation of the coating liquid is maintained at a predetermined high temperature range for a predetermined time. By using the method according to (1), it is possible to manufacture an optical information recording medium having a low jitter value and excellent recording / reproducing characteristics with few reading errors during reproduction. Further, fluorinated cyclic alkanes or alkenes, particularly 1,1,2,2,3,3,4-heptafluorocyclopentane, are relatively inexpensive and can be obtained by using this compound as a solvent. The manufacturing cost of the information recording medium can be reduced.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H111 EA03 EA12 EA22 EA25 EA37 EA44 FA01 FB42 GA05 5D029 JA04 JC20 5D121 AA01 EE22 EE24 EE28 GG11 GG28

Claims (6)

[Claims] 1. A method for manufacturing an optical information recording medium, comprising a step of coating and forming a dye recording layer capable of recording information by irradiating a laser beam on a transparent disk-shaped substrate. After adding a dye to a solvent containing a fluorinated cyclic alkane or alkene to obtain a dye-solvent mixture,
The mixture is maintained at a temperature of 45 ° C. or higher and a temperature of 5 ° C. or lower of the boiling point of the solvent for 5 minutes to 2 hours to prepare a coating solution. Then, the coating solution is coated on a substrate and dried. A method for manufacturing an optical information recording medium. 2. The solvent according to claim 1, wherein the fluorinated cyclic alkane or alkene is contained in the solvent in a volume of 60% or more.
3. The method for manufacturing an optical information recording medium according to claim 1. 3. The method for producing an optical information recording medium according to claim 1, wherein 1,1,2,2,3,3,4-heptafluorocyclopentane is used as the fluorinated cyclic alkane or alkene. 4. An operation of maintaining the mixture in a temperature range of 45 ° C. or higher and a boiling point of the solvent of 5 ° C. or lower for 5 minutes to 2 hours while applying ultrasonic waves to the mixture. 3. The method for manufacturing an optical information recording medium according to any one of the items 3. 5. The method for manufacturing an optical information recording medium according to claim 1, wherein the application of the application liquid onto the substrate is performed at a temperature of 40 ° C. or less. 6. An optical information recording medium provided with a dye recording layer capable of recording information by irradiating a laser beam on a transparent disc-shaped substrate, wherein the dye recording layer contains a fluorinated cyclic alkane or alkene. A dye-solvent mixture obtained by adding a dye to a solvent is heated at 45 ° C. or higher and having a boiling point of 5
An optical information recording medium formed by using a coating solution prepared by maintaining the composition in a temperature range of not more than ℃ for 5 minutes to 2 hours.