JPH11151861A - Optical information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an optical information recording medium suitable for a high density recording using a semiconductor laser having an oscillating wavelength in a short wavelength, and improve preservation stability, heat-resistance and light-resistance by containing a specified compound in the recording layer. SOLUTION: In the recording layer, a compound which is represented by the formula is contained. In the formula, A indicates a benzene ring which may have a substitutional group, X indicates hydrogen atom, a low class alkyl group, halogen atom or a hydroxyl group, R indicates hydrogen atom, a substituted or unsubstituted alkyl group, an allyl group or an unsubstituted aryl group, and B indicates a substituted or unsubstituted alkylene group of which the number of carbon atoms is 2 or 3. By this method, this recording medium has a sufficient sensitivity and a reflectance for DVD-R using a laser beam especially in the vicinity of 635 nm, for laser beams at 700 nm or lower, and this recording medium is suitable for a high density recording wherein a recording and the reproduction are possible. Also, without using a quencher, the preservation stability is favorable, and in addition, the heat-resistance and the light-resistance are excellent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium, and more particularly to a writable write-once optical information recording medium having a recording film containing an organic dye.

[0002]

2. Description of the Related Art Optical information recording media have come to be widely used because of their excellent characteristics, such as generally having a large storage capacity and recording / reproducing without contact.

In current write-once type (WORM, CD-R) optical disks, a laser is focused on a very small area of a recording film.
Pits are formed in the recording film, and reproduction is performed based on the difference in the amount of reflected light or transmitted light between the pit portion and a portion where no pit is formed. It is generally well known that an organic dye is used for a recording film of this write-once type optical recording medium. In order to smoothly change the properties of the recording film, the medium generally has a so-called air sandwich structure in which two recording media are provided on a substrate and the recording films are arranged to face each other. It is. However, with an increase in the amount of information, attempts have been made to shorten the wavelength of the semiconductor laser from the current level and perform high-density recording. Conventional cyanine dyes used in write-once optical recording media have sufficient sensitivity and absorbance near 635-650 nm, which is the wavelength of laser used for high-density recording. There is a problem that can not be. Furthermore, the cyanine dye alone is slightly inferior in heat resistance and light resistance and generally carries a singlet oxygen quencher. In recent years, however, there has been an active movement to recycle the solution for cost reduction. Therefore, the solution is ideally composed of only the dye and the solvent, the storage stability of the dye itself,
Improvement of heat resistance and light resistance has been an issue. Also, from the viewpoint of cost, it is easy to manufacture the dye itself,
Dyes having properties such as excellent film-forming properties have been demanded.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and it is an object of the present invention to be suitable for high-density recording using a semiconductor laser having an oscillation wavelength at a short wavelength. An object of the present invention is to provide an optical information recording medium having excellent stability, heat resistance and light resistance.

[0005]

The present inventors have made intensive efforts to solve the above-mentioned problems, and as a result, completed the present invention. That is, the present invention provides (1) an optical recording medium having a recording layer provided directly or via an undercoat layer on a substrate, wherein the recording layer has the following formula (1)

[0006]

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(In the formula (1), A represents a benzene ring which may have a substituent, X represents a hydrogen atom, a lower alkyl group, a halogen atom or a hydroxyl group, and R represents a hydrogen atom, substituted or unsubstituted. Represents an alkyl group, an allyl group or a substituted or unsubstituted aryl group, and B represents a substituted or unsubstituted alkylene group having 2 or 3 carbon atoms.)
An optical information recording medium comprising a compound represented by the formula: (2) wherein the substituent of A is a nitro group, a cyano group, a carboxyl group, a halogen atom, an alkyl group, a trifluoromethyl group, an alkoxy group, or an alkoxy group; The optical information recording medium according to (1), which is a carbonyl group, an acyl group, an acylamino group, an alkylsulfonyl group, an aminocarbonyl group, an alkylaminosulfonyl group, an alkylaminocarbonyl group, or a thiocyano group; The optical information recording medium according to (1), which is a benzene ring substituted with a halogen atom, (4) a compound represented by the formula (1), wherein A is a benzene ring substituted with two chlorine atoms, A mixture of a compound having 5-position and 6-position and a compound having 6-position and 7-position in the benzothiazole skeleton having the benzene ring (5) The optical information recording medium according to any one of (1) to (4), wherein B is a substituted or unsubstituted alkylene group having 3 carbon atoms. (6) An optical information recording medium, wherein at least one compound according to any one of (1) to (5) and a singlet oxygen quencher are carried thereon, (7) recording. An optical information recording medium provided with a metal reflective layer and a protective layer on a layer, wherein the metal reflective layer is gold,
One of silver and aluminum as a main component,
The optical information recording medium according to any one of (1) to (6), wherein the protective layer is made of an ultraviolet curable resin.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In R of the general formula (1), examples of the unsubstituted alkyl group include a methyl group, an ethyl group,
Examples thereof include a C1-C8 linear or branched alkyl group such as a propyl group, a butyl group, and an octyl group. Examples of the substituted alkyl group include a 2-hydroxyethyl group,
Hydroxy-substituted alkyl groups such as -hydroxybutyl group and 2-hydroxypropyl group, carboxymethyl group, 2-
A carboxy-substituted (C1-C4) alkyl group such as a carboxyethyl group and a 3-carboxypropyl group; a cyano-substituted (C1-C4) alkyl group such as a 2-cyanoethyl group;
Halogen atom-substituted (C1-C4) alkyl groups such as chloroethyl group, 3-chloropropyl group, 2-chloropropyl group, 2,2,2-trifluoroethyl group, and phenyl substitution such as benzyl group and 2-phenylethyl group Alkyl group, 2-methoxyethyl group, 2-ethoxyethyl group, 2
-(N-propoxy) ethyl group, 2-isopropoxyethyl group, 2- (n-butoxy) ethyl group, 2-isobutoxyethyl group, 2- (2-ethylhexyloxy) ethyl group, 3-methoxypropyl group, (C1-C8) alkoxy-substituted (C1-C4) alkyl groups such as 4-methoxybutyl group and 2-methoxypropyl group, 2- (2-methoxyethoxy) ethyl group, 2- (2-ethoxyethoxy)
Ethyl group, 2- (2- (n-propoxy) ethoxy) ethyl group, 2- (2-isopropoxyethoxy) ethyl group, 2- (2- (n-butoxy) ethoxy) ethyl group,
2- (2-isobutoxyethoxy) ethyl group, 2- {2
(C1-C8) alkoxy (C1-C4) alkoxy-substituted (C1-C4) alkyl groups such as-(2-ethylhexyloxy) ethoxydiethyl group, 2-acetyloxyethyl group, 2-propionyloxyethyl group, (N-
Substitution of acyloxy group such as butyryl) oxyethyl group, 2-isobutyryloxyethyl group, 2-trifluoroacetyloxyethyl group, benzoyloxyethyl group (C1
-C4) alkyl group, methoxycarbonylmethyl group, ethoxycarbonylmethyl group, (n-propoxy) carbonylmethyl group, isopropoxycarbonylmethyl group, n
-Butoxycarbonylmethyl group, isobutoxycarbonylmethyl group, 2-ethylhexyloxycarbonylmethyl group, benzyloxycarbonylmethyl group, 2-methoxycarbonylethyl group, 2-ethoxycarbonylethyl group, n-propoxycarbonylethyl group, isopropoxycarbonyl An optionally substituted (C1-C8) alkoxycarbonyl such as an ethyl group, an n-butoxycarbonylethyl group, an isobutoxycarbonylethyl group, a 2- (2-ethylhexyloxycarbonyl) ethyl group, or a 2-benzyloxycarbonylethyl group Substitution (C1-C
4) an alkyl group, a furfuryloxycarbonyl (C1-C4) alkyl group such as a furfuryloxycarbonylmethyl group or a 2-furfuryloxycarbonylethyl group;
-Methoxycarbonyloxyethyl group, 2-ethoxycarbonyloxyethyl group, 2- (n-propoxy) carbonyloxyethyl group, 2-isopropoxycarbonyloxyethyl group, 2- (n-butoxy) carbonyloxyethyl group, 2- Optionally substituted (C1-C8) alkoxycarbonyloxy-substituted (C1-C4) such as isobutoxycarbonyloxyethyl, 2- (2-ethylhexyloxycarbonyloxy) ethyl, 2-benzyloxycarbonyloxyethyl, etc. Alkyl group,
Examples include a heterocyclic-substituted (C1-C4) alkyl group such as a furfuryl group and a tetrahydrofurfuryl group, and a 2-furfuryloxycarbonyloxyethyl group. The aryl group includes a phenyl group or a fluorine atom, a chlorine atom,
Examples include a phenyl group having a substituent such as a methyl group or a methoxy group.

In X, examples of the halogen atom include a fluorine atom, a chlorine atom and a bromine atom. Examples of the lower alkyl group include a linear or branched C1-C4 alkyl group, and specific examples include a methyl group, an ethyl group, a butyl group, and an isopropyl group.

Examples of the halogen atom as a substituent of the benzene ring A include a fluorine atom, a chlorine atom and a bromine atom, and examples of the alkyl group include a C1 to C6 linear or branched alkyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, and an isobutoxy group. Examples of the alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, and an n- Propoxycarbonyl group, isopropoxycarbonyl group,
n-butoxycarbonyl group, isobutoxycarbonyl group, n-hexyloxycarbonyl group, 2-ethylhexyloxycarbonyl group and the like. Examples of the acyl group include acetyl group, propionyl group and benzoyl group, and acylamino group. Examples thereof include an acetylamino group, a propionylamino group and a benzoylamino group.Examples of the alkylsulfonyl group include a methylsulfonyl group and an ethylsulfonyl group.Examples of the alkylaminosulfonyl group include N-methylaminosulfonyl. Group, N-ethylaminosulfonyl group, N- (n-propyl) aminosulfonyl group, N-isopropylaminosulfonyl group, N- (n-butyl) aminosulfonyl group, N-isobutylaminosulfonyl group, N, N-dimethylamine Nosulfonyl group, N, N-diethylaminosulfonyl group, N, N-di (n-propyl) aminosulfonyl group, N, N-diisopropylaminosulfonyl group, N, N-di (n-butyl) aminosulfonyl group, N , N-diisobutylaminosulfonyl group and the like, and examples of the alkylaminocarbonyl group include an N-methylaminocarbonyl group, an N-ethylaminocarbonyl group, an N- (n-propyl) aminocarbonyl group, and an N-isopropylaminocarbonyl group. , N- (n-
Butyl) aminocarbonyl group, N-isobutylaminocarbonyl group, N, N-dimethylaminocarbonyl group,
N, N-diethylaminocarbonyl group, N, N-di (n
-Propyl) aminocarbonyl group, N, N-diisopropylaminocarbonyl group, N, N-di (n-butyl) aminocarbonyl group, N, N-diisobutylaminocarbonyl group and the like.

In B, examples of the unsubstituted alkylene group include an ethylene group and a propylene group, and examples of the substituent of the substituted alkylene group include a lower alkyl group.

In R of the benzothiazole azo dye represented by the general formula (1), (C1 to C4) alkyl, hydroxyethyl, cyanoethyl, chloroethyl, (C1 to C4)
C4) an alkoxy-substituted (C1-C4) alkyl group,
2 to C4) acyloxy (C1 to C4) alkyl groups,
(C1-C6) alkoxycarbonyl (C1-C4) alkyl group, (C1-C4) alkoxy (C1-C4) alkoxy (C1-C4) alkyl group, allyl group, X represents a hydrogen atom, a halogen atom (particularly a chlorine atom Or a fluorine atom), a methyl group or B, an ethylene group or a propylene group, and ring A are preferably unsubstituted or disubstituted halogen atoms (particularly chlorine atoms or bromine atoms). In the case of a disubstituted compound, the substitution position of the substituent is such that one of the substituents is at position 6 and the other is at position 4.
It is preferably at the 5th or 7th position. The substitution positions are numbered clockwise with the sulfur atom of the benzothiazole skeleton as number 1.

As a preferable combination of these substituents, for example, A has two chlorine atoms as substituents, X is a hydrogen atom, B is a propylene group, and R is (C
2 to C8) alkoxy (C1 to C4) alkyl groups. Here, the substitution position of the chlorine atom of ring A is the 5-position and the 6-position or the 6-position and the 7-position.

Specific examples of the compound represented by the general formula (1) in the present invention are shown in Table 1, but are not limited thereto. In addition, the numbers in A and X in Table 1 are the numbers indicating the substitution positions, and in A, the numbers are given clockwise with the sulfur atom of the benzothiazole skeleton being number 1. It is known that the disubstituted benzothiazole is a 1: 1 mixture of 5,6-substituted and 6,7-substituted, and this is represented as Cl2. In addition, X is numbered counterclockwise with the nitrogen atom of the tetrahydroquinoline ring or indoline skeleton being number 1.
Further, in B, the carbon atoms bonded to the nitrogen atoms are on the right, and are listed from left to right.

[0015]

[Table 1] Table 1 Compound No. AXBR1 Cl2 H C3H6 C2H4OCH3 2 Cl2 H C3H6 C2H5 3 Cl2 H C3H6 C2H4OC4H9 4 Cl2 H C3H6 C2H4OC2H4OC2H5 5 Cl2 H C3H6 C2H2 C3 C2 H2 C5 8 Cl2 7-Cl C3H6 C2H5 9 Cl2 7-CH3 C3H6 C2H4OCH3 10 Cl2 H C2H4 C2H4OC2H5 11 6-CN H C3H6 CH2CH = CH2 12 Cl2 H CH (CH3) CH2C (CH3) 2 C2H4OC2H5 13 Cl2 7-OH C2H4

The compound of the present invention represented by the above general formula (1) is a compound of the formula (2)

[0017]

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The 2-aminobenzothiazole derivative represented by (A is the same as described above) is diazotized by a known method,
Equation (3)

[0019]

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(X, R, and B are the same as described above), and can be synthesized by coupling with a tetrahydroquinoline derivative or an indoline derivative.
Details of the synthesis method are described in, for example, JP-A-9-255885.

The compounds used in the optical recording medium of the present invention may be used alone or as a mixture. Dyes other than the compounds used in the present invention, for example, dyes having different absorption wavelengths,
Preferably, it may be used in combination with an organic dye having a maximum absorption wavelength of 670 to 740 nm. Such dyes include, for example, pentamethine cyanine dyes, squarylium dyes, indoaniline dyes, phthalocyanine dyes, more preferably pentamethine cyanine dyes,
Examples include phthalocyanine dyes and azo metal chelate dyes.

Further, various antioxidants, ultraviolet absorbers, and singlet oxygen quenchers may be used in combination to further improve reading durability and light resistance. Examples of the singlet oxygen quencher include transition metal complexes such as common nickel complexes and copper complexes, nitroso compounds of diphenylamine, aminium-based and diimonium-based compounds (for example, IRG-002, IRG-022, IR
G-023). Further, various resins may be used in combination. The quencher is generally used in an amount of 0.01 to 10 mol, preferably 0.03 to 2.0 mol, per 1 mol of the compound of the formula (1).

The optical information recording medium of the present invention comprises a substrate and a recording layer containing the compound represented by the general formula (1), and if necessary, a reflective layer and a protective layer are provided. Any known substrate can be used. For example, a glass plate, a metal plate or a plastic plate or a film may be mentioned, and examples of the plastic include an acrylic resin, a polycarbonate resin, a methacrylic resin, a polysulfone resin,
Examples include a polyimide resin, an amorphous polyolefin resin, a polyester resin, and a polypropylene resin. Examples of the shape of the substrate include various shapes such as a disk shape, a card shape, a sheet shape, and a roll film shape.

A guide groove may be formed on the glass or plastic substrate to facilitate tracking during recording. A glass or plastic substrate may be provided with an undercoat layer such as a plastic binder or an inorganic oxide or an inorganic sulfide. The undercoat layer preferably has a lower thermal conductivity than the substrate. The thickness of the undercoat layer is 0.01 to
30 μm, preferably 0.05 to 10 μm is suitable.

The recording layer in the present invention comprises, for example, a compound represented by the general formula (1) and, if necessary, a quencher, a known organic solvent such as tetrafluoropropanol, diacetone alcohol, methanol, ethanol or butanol. , Dissolved in methyl cellosolve, ethyl cellosolve, dichloroethane, isophorone, cyclohexanone, etc., and, if necessary, by adding an appropriate binder, and applying the solution on a substrate by a spin coater, bar coater, roll coater, or the like. I can do it. Other methods include a vacuum deposition method, a sputtering method, a doctor blade method, a casting method, and a dipping method in which a substrate is immersed in a solution.

The thickness of the recording layer is 0.01 to 5 μm, preferably 0.02 to 3 μm. This value is 0.01 μm
If it is less than 1, recording sensitivity and reflectivity may be insufficient, and ideal recording may not be performed. On the other hand, this value
If m exceeds m, the recording sensitivity may be insufficient.

The optical recording medium of the present invention can be provided with an undercoat layer on the substrate, a protective layer on the recording layer, and a reflective layer on the substrate or the recording layer, if necessary. When a reflective layer is provided, the reflective layer is made of a metal such as gold, silver, copper, or aluminum, preferably gold, silver, or aluminum, and may be used alone or as an alloy of two or more. This is formed by a vacuum deposition method, a sputtering method, an ion plating method, or the like. The thickness of such a reflective layer is 0.02 to 2 μm. The protective layer, which may be provided on the reflective layer, is generally formed by applying an ultraviolet curable resin by a spin coating method and then irradiating ultraviolet rays to cure the coating film. In addition, an epoxy resin, an acrylic resin, a silicone resin, a urethane resin, or the like is also used as a material for forming the protective film. The thickness of such a protective film is usually 0.01 to 100 μm.

The optical recording medium of the present invention is preferably a DVD
Used for -R. For recording information or forming an image, a laser, for example, a semiconductor laser, a helium-neon laser, a He-Cd laser, a YAG laser,
It is performed by irradiating the recording layer with a focused high-energy beam such as an r laser through the substrate or from the opposite side of the substrate. Reading of information or images is performed by irradiating a low-power laser beam. ,
The detection is performed by detecting the difference between the amount of reflected light or the amount of transmitted light between the pit portion and a portion where no pit is formed.

[0029]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, parts are by weight unless otherwise specified.

Synthesis Example 1 2-amino-5,6-dichlorobenzothiazole and 2-amino-5,6-dichlorobenzothiazole
Mixture of amino-6,7-dichlorobenzothiazole 2
After dissolving 2 parts in 186 parts of concentrated sulfuric acid,
26 parts were added dropwise. This is cooled to -4 ° C and 40%
After dropping 42 parts of nitrosylsulfuric acid, the mixture was stirred at 0 to 5 ° C for 3 hours to obtain a diazo liquid. On the other hand, N-methoxyethyl-
A coupler liquid was prepared by dissolving 19.1 parts of 1,2,3,4-tetrahydroquinoline in 50 parts of acetic acid. The diazo solution was added dropwise to the prepared solution at 0 to 5 ° C., and the mixture was stirred for 2 hours. Thereafter, the mixture was neutralized with an aqueous sodium hydroxide solution to pH 4 and stirred overnight, and then the obtained compound was filtered, washed with water,
No. is obtained by drying. Compound 1 was obtained. λmax 5
40 nm (acetone)

Other examples of compounds are also described in Synthesis Example 1 above.
The corresponding benzothiazole derivative is synthesized in the same manner as described above, and the corresponding benzothiazole derivative is reacted with the corresponding tetrahydroquinoline derivative or indoline derivative.

Example 1 (Example of recording medium) 0.08 part of compound 1 was dissolved in 4 parts of tetrafluoropropanol to obtain a coating solution. 2 ml of this solution
Was dropped on a 5-inch polycarbonate resin substrate with a groove by a pipette, applied by a spin coater, and dried at 50 ° C. for 5 minutes to form a recording layer. The maximum absorption wavelength of the coating film was 528 nm. When the obtained coating film was irradiated with a semiconductor laser beam having a center wavelength of 635 nm at an output of 7 mW, pits with clear contours were formed. Further, while rotating the coated substrate at 3.8 m / s, the central wavelength 63
Irradiation was performed at a recording frequency of 1 MHz with a semiconductor laser beam of 5 nm, and an evaluation revealed that a C / N ratio of 59 db was obtained. The storage stability of this coating film is 20 at 60 ° C. × 80% RH.
Good for more than a day.

[0033]

The optical information recording medium of the present invention has a structure in which a specific recording film containing a compound having a specific structure is provided on a substrate. It has sufficient sensitivity and reflectivity for DVD-R using light, is suitable for high-density recording that can be recorded and reproduced, and has good storage stability without using a quencher. Excellent heat resistance and light resistance. Further, since the compound having a specific structure used here is excellent in film-forming properties and relatively inexpensive, it is highly useful in terms of cost reduction.

Claims (7)

[Claims] In an optical recording medium having a recording layer provided on a substrate directly or via an undercoat layer, the following formula (1) is embedded in the recording layer. (In the formula (1), A represents a benzene ring which may have a substituent, X represents a hydrogen atom, a lower alkyl group, a halogen atom or a hydroxyl group, and R represents a hydrogen atom, a substituted or unsubstituted alkyl group. , An allyl group or a substituted or unsubstituted aryl group, and B represents a substituted or unsubstituted alkylene group having 2 or 3 carbon atoms.) . 2. The substituent of A is a nitro group, cyano group, carboxyl group, halogen atom, alkyl group, trifluoromethyl group, alkoxy group, alkoxycarbonyl group, acyl group, acylamino group, alkylsulfonyl group, aminocarbonyl group. 2. The optical information recording medium according to claim 1, which is an alkylaminosulfonyl group, an alkylaminocarbonyl group, or a thiocyano group. 3. The optical information recording medium according to claim 1, wherein A is a benzene ring substituted with a cyano group or a halogen atom. 4. A compound represented by the formula (1) wherein A is 2
A mixture of a compound having 5- and 6-positions and a compound having 6- and 7-positions in a benzothiazole skeleton having the benzene ring, wherein the benzene ring is substituted with two chlorine atoms. 2. The optical information recording medium according to 1. 5. The optical information recording medium according to claim 1, wherein B is a substituted or unsubstituted alkylene group having 3 carbon atoms. 6. An optical information recording medium comprising at least one compound according to any one of claims 1 to 5 and a singlet oxygen quencher. 7. An optical information recording medium comprising a recording layer provided with a metal reflection layer and a protective layer, wherein the metal reflection layer contains any one of gold, silver and aluminum as a main component, and the protection layer is The optical information recording medium according to any one of claims 1 to 6, comprising an ultraviolet curable resin.