JP2000222772A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical recording medium capable of excellently recording and reproducing data with laser light in a specified wavelength range by incorporating a compd. having benzoxazole ring or benzothiazole rings having phenyl substituents into a recording layer on a substrate. SOLUTION: A compd. expressed by formula I is incorporated into the recording layer of an optical recording medium having at least a recording layer and a reflection layer on a substrate so that the obtd. write-once optical recording medium enables recording and reproducing with laser light of the wavelength selected from a 400 to 500 nm range. The compd. of formula I is obtd. by the reaction of a compd. expressed by formula II and a compd. expressed by formula III with hydrochloric acid or the like as a catalyst. In formula I, each of R1 to R8 is H, a halogen atom, <=20C alkyl group, alkoxy group, alkylthio group, aryloxy group, arylthio group, alkenyl group, aralkyl group, acyl group, aryl group, heteroaryl group or alkylsulfonate group; X is O or S; and A is a <=20C aryl group or heteroraryl group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium, and more particularly to a recordable optical recording medium containing a compound which can be recorded and reproduced by a blue laser beam.

[0002]

2. Description of the Related Art As an optical recording medium having a reflective layer on a substrate, a recordable CD-R (CD-Recordable) conforming to the compact disk (hereinafter abbreviated as CD) standard is used.
e) is widespread. CD-R recording capacity is 0.6
Although it is about 5 GB, with the dramatic increase in the amount of information, demands for higher density and larger capacity of information recording media are increasing.

[0003] By shortening the wavelength of a recording and reproducing laser, a beam spot can be reduced, and high-density optical recording can be performed. Recently, the development of short wavelength semiconductor lasers used in optical disk systems has been advanced,
Red semiconductor lasers of 0 nm, 650 nm and 635 nm have been put into practical use [for example, Nikkei Electronics, No. 592, p. 65, October 11, 1993]. A DVD in which a moving image of two hours or more is digitally recorded using these semiconductor lasers has been put to practical use. DV
Since D is a read-only medium, a write-once optical recording medium (DVD-R) corresponding to this capacity is also being developed.

[0004] Further, development of blue semiconductor lasers having a wavelength of 400 nm to 500 nm capable of recording at a very high density has been rapidly progressing [for example, Nikkei Electronics, N.
o. 708, p. 117, January 26, 1998 issue],
A write-once optical recording medium corresponding to this is also being developed.

When pits are formed by irradiating a laser beam to a recording layer of a write-once optical recording medium to cause a physical change or a chemical change in the recording layer, a pit having good optical constants and decomposition behavior of the compound is formed. It is an important factor to make it happen. Those that are difficult to decompose have reduced sensitivity, while those that are severely decomposed or are subject to change have a greater effect between pits and in the radial direction, making reliable pit formation difficult. Conventional CD-R media have a low refractive index of the recording layer at the wavelength of the blue semiconductor laser used in ultra-high density recording,
Since the extinction coefficient is not an appropriate value, good recording and recording can be achieved by lowering the reflectance, increasing the error rate, and increasing the jitter.
Cannot play. Therefore, it is necessary to select an appropriate compound having an optical property and a decomposition behavior for a blue semiconductor laser as the compound used for the recording layer.

However, examples of organic dye compounds actually proposed are cyanine compounds described in JP-A-4-74690 and porphyrin compounds described in JP-A-7-304256 or JP-A-7-304257. There are only very limited examples.

[0007]

However, since the cyanine compound generally has low light resistance, it sometimes becomes impossible to reproduce the medium when the medium is stored for a long period of time.
The porphyrin compound described in the above publication is disclosed in
As described in the examples of JP-A-304256 or JP-A-7-304257, when the recording layer of the optical recording medium is used alone, it is impossible to write with a laser beam. It cannot be said that the compound used has sufficiently satisfactory performance. Further, in the optical recording medium disclosed in the publications, it is essential to use a mixture of a single molecule or a high molecular compound having a substituent coordinating with an organic dye.
Since the recording layer may become cloudy as in the sample disk described in the Example column of JP-A-7, the production of the medium is complicated, for example, it is necessary to set the composition ratio. Room was left. Therefore, there is an urgent need to develop a dye for an optical recording medium suitable for producing a medium having ultra-high density recording and excellent long-term storage stability.

[0008] The object of the present invention is to provide a wavelength of 400 nm to 500 nm.
An object of the present invention is to provide an optical recording medium having, in a recording layer, a compound suitable for ultra-high-density recording that enables good recording and reproduction with a laser beam selected from the range of nm.

[0009]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, completed the present invention. That is, the present invention provides an optical recording medium having at least a recording layer and a reflective layer on a substrate, wherein the recording layer contains a compound represented by the following general formula (1):

[0010]

Embedded image

[Wherein, R _{1 to} R ₈ each independently represent a hydrogen atom,
Halogen atom, substituted or unsubstituted alkyl group having 20 or less carbon atoms, alkoxy group, alkylthio group, aryloxy group, arylthio group, alkenyl group, aralkyl group, acyl group, aryl group, heteroaryl group, or alkylsulfonic acid group X represents an oxygen atom or a sulfur atom, and A represents a substituted or unsubstituted aryl or heteroaryl group having 20 or less carbon atoms. The optical recording medium according to the above, wherein A of the compound represented by the general formula (1) is a substituted or unsubstituted phenyl group, naphthyl group, furyl group, pyrrolyl group, or thienyl group, a wavelength of 400 nm to 500 nm. And an optical recording medium capable of recording and reproducing with respect to a laser beam selected from the group consisting of:

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The concrete constitution of the present invention will be described below.

This optical recording medium has a four-layer structure in which a substrate 1, a recording layer 2, a reflective layer 3, and a protective layer 4 are sequentially laminated. This may be used as a single plate as shown in FIG.
As shown in FIG. 2, the bonding may be performed with an adhesive layer 5 like a DVD.

The material of the substrate is basically required to be transparent at the wavelengths of the recording light and the reproducing light. For example, polymer materials such as acrylic resins such as polycarbonate resin, vinyl chloride resin and polymethyl methacrylate, polystyrene resins and epoxy resins, and inorganic materials such as glass are used.
These substrate materials are formed into a disk shape by injection molding or the like. If necessary, guide grooves or pits may be formed on the substrate surface. Such guide grooves and pits
It is desirable to apply it at the time of molding the substrate, but it can also be applied using an ultraviolet curable resin layer on the substrate.

In the present invention, a recording layer is provided on a substrate. The recording layer of the present invention contains a compound represented by the general formula (1).

The general formula (1) contained in the recording layer of the present invention
Specific examples of R _{1 to} R ₈ of the compound represented by are described below.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

The substituted or unsubstituted alkyl group includes
Linear, branched or cyclic alkyl group, alkoxyalkyl group, alkoxyalkoxyalkyl group, alkoxyalkoxyalkoxyalkyl group, alkoxycarbonylalkyl group, alkoxycarbonyloxyalkyl group, alkoxyalkoxycarbonyloxyalkyl group, hydroxyalkyl group, hydroxyalkoxyalkyl Group, hydroxyalkoxyalkoxyalkyl group,
Cyanoalkyl group, acyloxyalkyl group, acyloxyalkoxyalkyl group, acyloxyalkoxyalkoxyalkyl group, alkyl halide, sulfonealkyl group, alkylcarbonylaminoalkyl group, alkylsulfonaminoalkyl group, sulfonamidoalkyl group, alkylaminoalkyl group, amino Alkyl group,
And alkylsulfonealkyl groups.

The straight-chain, branched or cyclic alkyl group may be a methyl group, an ethyl group, an n-propyl group, an iso-propyl group in consideration of workability by coating on a polycarbonate, acrylic, epoxy, polyolefin substrate or the like. , N-butyl group, iso-butyl group, sec-
Butyl group, t-butyl group, n-pentyl group, iso-pentyl group, 2-methylbutyl group, 1-methylbutyl group,
neo-pentyl group, 1,2-dimethylpropyl group,
1,1-dimethylpropyl group, cyclo-pentyl group, n-hexyl group, 4-methylpentyl group, 3-methylpentyl group, 2-methylpentyl group, 1-methylpentyl group, 3,3-dimethylbutyl group, 2,3-dimethylbutyl group, 1,3-dimethylbutyl group, 2,2-dimethylbutyl group, 1,2-dimethylbutyl group, 1,1-dimethylbutyl group, 3-ethylbutyl group, 2-ethylbutyl group, 1-ethylbutyl group, 1,2,2-trimethylbutyl group, 1,1,2-trimethylbutyl group, 1-ethyl-
2-methylpropyl group, cyclo-hexyl group, n-
Heptyl group, 2-methylhexyl group, 3-methylhexyl group, 4-methylhexyl group, 5-methylhexyl group,
2,4-dimethylpentyl group, n-octyl group, 2-ethylhexyl group, 2,5-dimethylhexyl group, 2,
5,5-trimethylpentyl group, 2,4-dimethylhexyl group, 2,2,4-trimethylpentyl group, 3,5
5-trimethylhexyl group, n-nonyl group, n-decyl group, 4-ethyloctyl group, 4-ethyl-4,5-methylhexyl group, n-undecyl group, n-dodecyl group,
1,3,5,7-tetraethyloctyl group, 4-butyloctyl group, 6,6-diethyloctyl group, n-tridecyl group, 6-methyl-4-butyloctyl group, n-tetradecyl group, n-pentadecyl group 3,5-dimethylheptyl group, 2,6-dimethylheptyl group, 2,4-dimethylheptyl group, 2,2,5,5-tetramethylhexyl group, 1-cyclo-pentyl-2,2-dimethylpropyl And a 1-cyclo-hexyl-2,2-dimethylpropyl group.

Examples of alkoxyalkyl groups include methoxymethyl, ethoxymethyl, propoxymethyl, butoxymethyl, methoxyethyl, ethoxyethyl, propoxyethyl, butoxyethyl, n-
Hexyloxyethyl group, 4-methylpentoxyethyl group, 1,3-dimethylbutoxyethyl group, 2-ethylhexyloxyethyl group, n-octyloxyethyl group,
3,5,5-trimethylhexyloxyethyl group, 2-
Methyl-1-iso-propylpropoxyethyl group, 3
-Methyl-1-iso-propylbutyloxyethyl group, 2-ethoxy-1-methylethyl group, 3-methoxybutyl group, 3,3,3-trifluoropropoxyethyl group, 3,3,3-trichloropropoxyethyl And the like.

Examples of the alkoxyalkoxyalkyl group include a methoxyethoxyethyl group, an ethoxyethoxyethyl group, a propoxyethoxyethyl group, a butoxyethoxyethyl group, a hexyloxyethoxyethyl group,
-Dimethylpropoxyethoxyethyl group, 3-methyl-
1-iso-butylbutoxyethoxyethyl group, 2-methoxy-1-methylethoxyethyl group, 2-butoxy-
1-methylethoxyethyl group, 2- (2′-ethoxy-
1′-methylethoxy) -1-methylethyl group, 3,
3,3-trifluoropropoxyethoxyethyl group,
3,3,3-trichloropropoxyethoxyethyl group and the like.

Examples of the alkoxyalkoxyalkoxyalkyl group include a methoxyethoxyethoxyethyl group,
Examples include an ethoxyethoxyethoxyethyl group, a butoxyethoxyethoxyethyl group, a 2,2,2-trifluoroethoxyethoxyethoxyethyl group, and a 2,2,2-trichloroethoxyethoxyethoxyethyl group.

Examples of the alkoxycarbonylalkyl group include methoxycarbonylmethyl, ethoxycarbonylmethyl, butoxycarbonylmethyl, methoxycarbonylethyl, ethoxycarbonylethyl, butoxycarbonylethyl, 2,2,3,3- Tetrafluoropropoxycarbonylmethyl group, 2,2,3,3-
And a tetrachloropropoxycarbonylmethyl group.

Examples of the alkoxycarbonyloxyalkyl group include a methoxycarbonyloxyethyl group, an ethoxycarbonyloxyethyl group, a butoxycarbonyloxyethyl group, a 2,2,2-trifluoroethoxycarbonyloxyethyl group, a 2,2,2 -Trichloroethoxycarbonyloxyethyl group and the like.

Examples of the alkoxyalkoxycarbonyloxyalkyl group include a methoxyethoxycarbonyloxyethyl group, an ethoxyethoxycarbonyloxyethyl group, a butoxyethoxycarbonyloxyethyl group,
Examples thereof include a 2,2,2-trifluoroethoxyethoxycarbonyloxyethyl group and a 2,2,2-trichloroethoxyethoxycarbonyloxyethyl group.

Examples of hydroxyalkyl groups include 2-
Hydroxyethyl group, 4-hydroxyethyl group, 2-hydroxy-3-methoxypropyl group, 2-hydroxy-
3-chloropropyl group, 2-hydroxy-3-ethoxypropyl group, 3-butoxy-2-hydroxypropyl group, 2-hydroxy-3-phenoxypropyl group, 2-
Examples include a hydroxypropyl group and a 2-hydroxybutyl group.

Examples of the hydroxyalkoxyalkyl group include a hydroxyethoxyethyl group, a 2- (2′-hydroxy-1′-methylethoxy) -1-methylethyl group,
2- (3'-fluoro-2'-hydroxypropoxy)
Examples include an ethyl group and a 2- (3′-chloro-2′-hydroxypropoxy) ethyl group.

Examples of the hydroxyalkoxyalkoxyalkyl group include a hydroxyethoxyethoxyethyl group, a [2 ′-(2′-hydroxy-1′-methylethoxy) -1′-methylethoxy] ethoxyethyl group,
[2 ′-(2′-fluoro-1′-hydroxyethoxy) -1′-methylethoxy] ethoxyethyl group,
[2 ′-(2′-chloro-1′-hydroxyethoxy)
-1'-methylethoxy] ethoxyethyl group.

Examples of the cyanoalkyl group include a 2-cyanoethyl group, a 4-cyanobutyl group, a 2-cyano-3-methoxypropyl group, a 2-cyano-3-chloropropyl group, and a 2-cyano-3-ethoxypropyl group. , 3-butoxy-2-cyanopropyl group, 2-cyano-3-phenoxypropyl group, 2-cyanopropyl group, 2-cyanobutyl group and the like.

Examples of acyloxyalkyl groups include acetoxyethyl, propionyloxyethyl, butyryloxyethyl, valeryloxyethyl, 1-ethylpentylcarbonyloxyethyl, 2,4,4-
Examples include a trimethylpentylcarbonyloxyethyl group, a 3-fluorobutyryloxyethyl group, a 3-chlorobutyryloxyethyl group, and the like.

Examples of the acyloxyalkoxyalkyl group include an acetoxyethoxyethyl group, a propionyloxyethoxyethyl group, a valeryloxyethoxyethyl group, a 1-ethylpentylcarbonyloxyethoxyethyl group, and a 2,4,4-trimethylpentylcarbonyloxy group. Examples include an ethoxyethyl group, a 2-fluoropropionyloxyethoxyethyl group, and a 2-chloropropionyloxyethoxyethyl group.

Examples of the acyloxyalkoxyalkoxyalkyl group include an acetoxyethoxyethoxyethyl group, a propionyloxyethoxyethoxyethyl group, a valeryloxyethoxyethoxyethyl group, a 1-ethylpentylcarbonyloxyethoxyethoxyethyl group,
Examples thereof include a 2,4,4-trimethylpentylcarbonyloxyethoxyethoxyethyl group, a 2-fluoropropionyloxyethoxyethoxyethyl group, and a 2-chloropropionyloxyethoxyethoxyethyl group.

Examples of the halogenated alkyl group include chloromethyl, chloroethyl, 2,2,2-trifluoroethyl, trifluoromethyl, bromomethyl,
And a methyl iodide group.

Examples of the sulfonealkyl group include a sulfonemethyl group, a sulfoneethyl group and a sulfonepropyl group.

Examples of the alkylcarbonylaminoalkyl group include a methylcarbonylaminoethyl group, an ethylcarbonylaminoethyl group, a propylcarbonylaminoethyl group, a cyclohexylcarbonylaminoethyl group, a succiniminoethyl group and the like.

Examples of the alkylsulfonaminoalkyl group include a methylsulfonaminoethyl group, an ethylsulfonaminoethyl group and a propylsulfonaminoethyl group.

Examples of the sulfonamidoalkyl group include:
Examples include a sulfonamidomethyl group, a sulfonamidoethyl group, and a sulfonamidopropyl group.

Examples of the alkylaminoalkyl group include:
N-methylaminomethyl group, N, N-dimethylaminomethyl group, N, N-diethylaminomethyl group, N, N-dipropylaminomethyl group, N, N-dibutylaminomethyl group and the like.

Examples of the aminoalkyl group include an aminomethyl group, an aminoethyl group and an aminopropyl group.

Examples of the alkylsulfonealkyl group include methylsulfonmethyl, ethylsulfonmethyl, butylsulfonmethyl, methylsulfonethyl, ethylsulfonethyl, butylsulfonethyl, 2,2,3,3- Examples thereof include a tetrafluoropropylsulfonemethyl group and a 2,2,3,3-tetrachloropropylsulfonemethyl group.

Examples of the substituted or unsubstituted alkoxy groups are alkoxy groups having the same substituents as the above-mentioned alkyl groups, and are preferably methoxy, ethoxy, n-propoxy, iso-propoxy. Group, n-
Lower alkoxy groups such as butoxy group, iso-butoxy group, sec-butoxy group, t-butoxy group, n-pentoxy group, iso-pentoxy group, neo-pentoxy group, and 2-methylbutoxy group.

Examples of the substituted or unsubstituted acyl groups are acyl groups having the same substituents as the above-mentioned alkyl groups, preferably formyl group, methylcarbonyl group, ethylcarbonyl group, n-propyl group. Carbonyl group, iso-propylcarbonyl group, n-butylcarbonyl group, iso-butylcarbonyl group, sec-butylcarbonyl group, t-butylcarbonyl group, n-pentylcarbonyl group, iso-pentylcarbonyl group, neo
-Pentylcarbonyl group, 2-methylbutylcarbonyl group, nitrobenzylcarbonyl group and the like.

Examples of the substituted or unsubstituted aryl groups are aryl groups having the same substituents as the above-mentioned alkyl groups, and are preferably phenyl, nitrophenyl, cyanophenyl, and hydroxyphenyl. , A methylphenyl group, a trifluoromethylphenyl group, a naphthyl group, a nitronaphthyl group, a cyanonaphthyl group, a hydroxynaphthyl group, a methylnaphthyl group, a trifluoromethylnaphthyl group and the like.

Examples of the substituted or unsubstituted aralkyl groups are aralkyl groups having the same substituents as the above-mentioned alkyl groups, preferably benzyl, nitrobenzyl, cyanobenzyl, hydroxybenzyl , Methylbenzyl, trifluoromethylbenzyl, naphthylmethyl, nitronaphthylmethyl, cyanonaphthylmethyl, hydroxynaphthylmethyl, methylnaphthylmethyl, trifluoromethylnaphthylmethyl and the like.

Examples of the substituted or unsubstituted alkenyl group include alkenyl groups having the same substituents as the above-mentioned alkyl groups, and are preferably a propenyl group,
Butenyl group, iso-butenyl group, 1-pentenyl group,
2-pentenyl group, 2-methyl-1-butenyl group, 3-
Lower alkenyl groups such as methyl-1-butenyl group, 2-methyl-2-butenyl group, 2,2-dicyanovinyl group, 2-cyano-2-methylcarboxylvinyl group, and 2-cyano-2-methylsulfonevinyl group Is mentioned.

Examples of the substituted or unsubstituted alkylthio group include the alkylthio groups having the same substituents as the above-mentioned alkyl groups, preferably a methylthio group,
Ethylthio group, n-propylthio group, iso-propylthio group, n-butylthio group, iso-butylthio group, s
and lower alkylthio groups such as an ec-butylthio group, a t-butylthio group, an n-pentylthio group, an iso-pentylthio group, a neo-pentylthio group, a 2-methylbutylthio group, and a methylcarboxylethylthio group.

Examples of the substituted or unsubstituted aryloxy group include aryloxy groups having the same substituents as the above-mentioned aryl groups, and are preferably phenoxy, 2-methylphenoxy, 4-methyl Examples include a phenoxy group, a 4-t-butylphenoxy group, a 2-methoxyphenoxy group, and a 4-iso-propylphenoxy group.

Examples of the substituted or unsubstituted arylthio groups are the arylthio groups having the same substituents as the above-mentioned aryl groups, preferably phenylthio, 4-methylphenylthio, 2-methoxyphenyl A thio group and a 4-t-butylphenylthio group.

Examples of the substituted or unsubstituted heteroaryl groups include pyrrolyl, thienyl, furanyl, oxazoyl, isoxazoyl, oxadiazoyl, imidazoyl, benzoxazoyl, benzothiazoyl, benzoimidazoyl. Group, benzofuranyl group, indoyl group and the like.

Examples of the substituted or unsubstituted alkylsulfone groups are the alkylsulfone groups having the same substituents as the above-mentioned alkyl groups, preferably a methylsulfone group, an ethylsulfone group, an n-propylsulfone group. Group, iso-propyl sulfone group, n-butyl sulfone group, iso-butyl sulfone group, sec-butyl sulfone group, t-butyl sulfone group, n-pentyl sulfone group, iso-butyl sulfone group, neo-pentyl sulfone group, Examples include a 2-methylbutylsulfone group, a 2-hydroxyethylsulfone group, and a 2-cyanoethylsulfone group.

The compound represented by the general formula (1) of the present invention can be prepared by a known method, for example, as described in J. Am. Am. Chem. So
c. 63, 3203 (1941) and the like. That is, it can be produced by reacting the compound represented by the general formula (2) with the compound represented by the general formula (3) using hydrochloric acid or the like as a catalyst.

[0052]

Embedded image [In the formulas (2) and (3), R _{1 to} R ₈ , X and A have the same meaning as described above. ]

Table 1 shows specific examples of the compound represented by the general formula (1).

[0054]

[Table 1]

[0055]

[Table 2]

In order to improve the recording characteristics, etc., it has an absorption maximum at a wavelength of 350 nm to 550 nm,
You may mix with compounds other than the above which have a large refractive index in 500 nm. Specifically, cyanine compounds, squarylium-based compounds, naphthoquinone-based compounds, anthraquinone-based compounds, tetrapyraporphyrazine-based compounds, indophenol-based compounds, pyrylium-based compounds, thiopyrylium-based compounds, azurenium-based compounds, triphenylmethane-based compounds, There are xanthene compounds, indasulen compounds, indigo compounds, thioindigo compounds, merocyanine compounds, thiazine compounds, acridine compounds, oxazine compounds, dipyrromethene compounds, and the like, and a mixture of a plurality of compounds may be used. . The mixing ratio of these compounds is about 0.1 to 30%.

When forming the recording layer, a quencher, a compound thermal decomposition accelerator, an ultraviolet absorber, an adhesive, or the like is mixed with the above-mentioned compound, if necessary, or has such an effect. It is also possible to introduce compounds as substituents of said compounds.

Specific examples of the quencher include bisacetylthionates, bisdithiols such as bisdithio-α-diketones and bisphenyldithiols, thiocateconals, salicylaldehyde oximes, and thiobisphenolates. Metal complexes are preferred. Also, amines are suitable.

The compound thermal decomposition accelerator is not particularly limited as long as it can confirm the promotion of the thermal decomposition of the compound by thermal weight loss analysis (TG analysis). Examples thereof include a metal anti-knocking agent and a metallocene compound. And metal compounds such as acetylacetonate-based metal complexes. Examples of the metal anti-knocking agent include tetraethyl lead, other lead compounds, and Simantrene [Mn (C ₅ H ₅ ) (CO)
Examples of Mn-based compounds such as [ ₃ ] and metallocene compounds include iron biscyclopentadienyl complex (ferrocene), Ti, V, Mn, Cr, Co, Ni, M
o, Ru, Rh, Zr, Lu, Ta, W, Os, Ir,
There are biscyclopentadienyl complexes such as Sc and Y.
Among them, ferrocene, ruthenocene, osmocene, nickelocene, titanocene and derivatives thereof have good thermal decomposition promoting effects.

Other iron-based metal compounds include, in addition to metallocene, organic iron compounds such as iron formate, iron oxalate, iron laurate, iron naphthenate, iron stearate and iron acetate; iron acetylacetonate complex; Phenanthroline iron complex, bispyridine iron complex, ethylenediamine iron complex,
Iron complexes such as iron complexes of ethylenediaminetetraacetate, iron complexes of diethylenetriamine, iron complexes of diethyleneglycol dimethylether, iron complexes of diphosphino and iron dimethylglyoximate, iron complexes such as carbonyl iron complexes, cyanoiron complexes and ammineiron complexes, Examples include iron halides such as iron, ferric chloride, ferrous bromide, and ferric bromide; inorganic iron salts such as iron nitrate and iron sulfate; and iron oxide. The thermal decomposition accelerator used here is desirably one that is soluble in an organic solvent and has good wet heat resistance and light resistance.

The various quencher and the compound thermal decomposition accelerator described above may be used singly or as a mixture of other types as required.

Further, if necessary, additives such as a binder, a leveling agent and an antifoaming agent may be added. Preferred binders include polyvinyl alcohol, polyvinylpyrrolidone, nitrocellulose, cellulose acetate, ketone resin, acrylic resin, polystyrene resin, urethane resin, polyvinyl butyral, polycarbonate, polyolefin and the like.

When a recording layer is formed on a substrate, in order to improve the solvent resistance, reflectance, recording sensitivity, etc. of the substrate,
A layer made of an inorganic substance or a polymer may be provided on the substrate.

Here, the content of the compound represented by the general formula (1) in the recording layer is 30% or more, preferably 60%.
% Or more. In addition, it is also preferable that it is substantially 100%.

The method for providing the recording layer includes, for example, a coating method such as a spin coating method, a spray method, a casting method, and a dipping method, a sputtering method, a chemical vapor deposition method, and a vacuum vapor deposition method. The spin coating method is simple. Is preferred.

When a coating method such as a spin coating method is used, the compound represented by the general formula (1) is dissolved or dispersed in a solvent so as to be 1 to 40% by weight, preferably 3 to 30% by weight. A coating solution is used, and at this time, it is preferable to select a solvent that does not damage the substrate.
For example, methanol, ethanol, isopropyl alcohol, octafluoropentanol, allyl alcohol, methyl cellosolve, ethyl cellosolve, alcohol solvents such as tetrafluoropropanol, hexane,
Aliphatic or alicyclic hydrocarbon solvents such as heptane, octane, decane, cyclohexane, methylcyclohexane, ethylcyclohexane, dimethylcyclohexane,
Aromatic hydrocarbon solvents such as toluene, xylene and benzene, halogenated hydrocarbon solvents such as carbon tetrachloride, chloroform, tetrachloroethane and dibromoethane,
Ether solvents such as diethyl ether, dibutyl ether, diisopropyl ether and dioxane; ketone solvents such as acetone and 3-hydroxy-3-methyl-2-butanone; ester solvents such as ethyl acetate and methyl lactate; and water. Can be These may be used alone or in combination.

The compound of the recording layer can be used by dispersing it in a polymer thin film or the like, if necessary.

When a solvent that does not damage the substrate cannot be selected, a sputtering method, a chemical vapor deposition method, a vacuum vapor deposition method, or the like is effective.

The thickness of the recording layer is 30 nm to 1000 nm.
However, it is preferably 50 nm to 300 nm. If the thickness of the recording layer is less than 50 nm, recording may not be performed due to large thermal diffusion, or a recording signal may be distorted and the signal amplitude may be reduced. The thickness is 300 nm.
If the thickness is larger, the reflectance may decrease, and the reproduction signal characteristics may deteriorate.

Next, on the recording layer, preferably,
A reflective layer having a thickness of 300 nm is formed. A reflection amplification layer or an adhesive layer can be provided between the recording layer and the reflection layer in order to increase the reflectance and improve the adhesion. As a material of the reflection layer, one having a sufficiently high reflectance at the wavelength of the reproduction light, for example, Au, Al, Ag, Cu, Ti, Cr, Ni, P
The metals t, Ta, Cr and Pd can be used alone or as an alloy. Among them, Au, Al,
Ag has a high reflectance and is suitable as a material for the reflective layer. In addition, the following may be included. For example, M
g, Se, Hf, V, Nb, Ru, W, Mn, Re, F
e, Co, Rh, Ir, Zn, Cd, Ga, In, S
Metals and metalloids such as i, Ge, Te, Pb, Po, Sn, Bi and the like can be mentioned. Further, those containing Au as a main component are preferable because a reflection layer having high reflectance can be easily obtained. Here, the main component means a component having a content of 50% or more. It is also possible to form a multilayer film by alternately stacking low-refractive-index thin films and high-refractive-index thin films with a material other than a metal, and use it as a reflective layer.

As a method of forming the reflection layer, for example,
Examples include a sputtering method, an ion plating method, a chemical vapor deposition method, and a vacuum vapor deposition method. In addition, a known inorganic or organic intermediate layer or adhesive layer may be provided on the substrate or below the reflective layer to improve the reflectance, the recording characteristics, and the adhesion.

The material of the protective layer formed on the reflective layer is not particularly limited as long as it protects the reflective layer from external force. Examples of the organic substance include a thermoplastic resin, a thermosetting resin, an electron beam curable resin, and an ultraviolet curable resin. Further, as the inorganic substance, Si
O ₂ , SiO, Si ₃ N ₄ , MgF ₂ , AlN, SnO _{2 and the} like can be mentioned. A thermoplastic resin, a thermosetting resin, or the like can be formed by dissolving in a suitable solvent, applying a coating solution, and drying. The UV-curable resin can be formed by applying the coating solution after it has been prepared as it is or by dissolving it in a suitable solvent, and then irradiating the coating with ultraviolet rays to cure the resin. As the ultraviolet curable resin, for example, acrylate resins such as urethane acrylate, epoxy acrylate, and polyester acrylate can be used. These materials may be used alone or as a mixture, and may be used not only as a single layer but also as a multilayer film.

As a method of forming the protective layer, a coating method such as a spin coating method or a casting method, a sputtering method, a chemical vapor deposition method, or the like is used as in the case of the recording layer. Among them, the spin coating method is preferable.

The thickness of the protective layer is generally 0.1 μm to 1 μm.
In the present invention, the range is from 3 μm to
It is 30 μm, more preferably 5 μm to 20 μm.

A label or the like can be further printed on the protective layer.

Alternatively, a protective sheet or a substrate may be bonded to the reflective layer surface, or two optical recording media may be bonded to each other with the reflective layer surfaces facing each other.

On the mirror side of the substrate, an ultraviolet curable resin, an inorganic thin film or the like may be formed to protect the surface or prevent adhesion of dust and the like.

Here, the wavelength of 400 nm to 5
The laser of 00 nm is not particularly limited. For example, a dye laser capable of selecting a wavelength in a wide range of the visible light region, a helium cadmium laser having a wavelength of 445 nm, and a laser having a wavelength of 48
8nm argon laser, wavelength about 390-410nm
GaN based semiconductor laser, wavelength about 850-860nm
And a semiconductor laser that oscillates a second harmonic of about 425 to 430 nm of the infrared laser. According to the present invention, high-density recording and reproduction can be performed at one wavelength or a plurality of wavelengths selected from these.

[0079]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited by these examples.

Example 1 Among the compounds represented by the general formula (1), the compound (1-
1) 0.2 g was dissolved in 10 ml of diacetone alcohol to prepare a compound solution.

Outer diameter 120 m made of polycarbonate resin and having continuous guide grooves (track pitch: 0.7 μm)
This compound solution was spin-coated on a disc-shaped substrate having a thickness of 0.6 mm and a thickness of 0.6 mm at a rotation speed of 2000 rpm, and dried at 70 ° C. for 3 hours to form a recording layer.

Au was sputtered on the recording layer using a sputtering apparatus manufactured by Shimadzu Corporation to form a reflective layer having a thickness of 100 nm. Argon gas was used as a sputtering gas. The sputtering was performed at a sputtering power of 0.5 A and a sputtering gas pressure of 1.0 × 10 ⁻³ Torr.

Further, an ultraviolet curable resin S
After spin-coating D-301 (manufactured by Dainippon Ink and Chemicals, Inc.), a substrate without a guide groove similar to the above-mentioned substrate was placed thereon, and the substrates were bonded by irradiating ultraviolet rays to produce an optical recording medium.

The pits were written on the optical recording medium having the recording layer formed as described above as follows.

An optical disk evaluation device (DDU-1000) manufactured by Pulstec Industrial equipped with a 430 nm blue harmonic conversion laser head (NA = 0.65) and KENWO
Using the OD EFM encoder, the shortest pit is 0.
A 4 μm EFM modulated signal was recorded at a linear velocity of 5.6 m / s and a laser power of 10 mW. After recording, the signal was reproduced with the laser output set to 0.5 mW using the same evaluation device,
As a result of measuring the reflectance, the error rate, and the jitter, all of the values showed good values. At the time of reproduction, an equalization process was performed.

The recorded medium was subjected to an accelerated deterioration test (humidity: 85% RT, 80 ° C. for 100 hours), and the reflectance, error rate, and jitter after the test were measured. It was confirmed to have.

Examples 2 to 23 An optical recording medium was prepared in the same manner as in Example 1 except that the compounds (1-2) to (1-23) were used for the recording layer. The signal was reproduced. In any case, the reflectance is 40% or more, and the error rate is 11 cps.
Hereinafter, a good value of 10% or less in jitter was shown. Also,
The change in reflectance after the accelerated deterioration test was 2% or less, the change in error rate was 2 cps or less, and the change in jitter was 1% or less, confirming excellent durability.

Table 2 shows the reflectance, error rate, and jitter value before and after the accelerated deterioration test in each example.

[0089]

[Table 3]

[0090]

According to the present invention, by using the compound represented by the general formula (1) as a recording layer, the wavelength of 400 nm to 5 nm, which is attracting much attention as a high-density optical recording medium, is obtained.
It is possible to provide a write-once optical recording medium that can be recorded and reproduced with a laser of 00 nm.

[Brief description of the drawings]

FIG. 1 is a sectional structural view showing an example of a layer configuration of an optical recording medium according to the present invention.

FIG. 2 is a sectional structural view showing an example of a layer configuration of an optical recording medium according to the present invention.

[Explanation of symbols]

 1: substrate 2: recording layer 3: reflective layer 4: protective layer 5: adhesive layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Denmi Misawa, Inventor 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Inside Mitsui Chemicals Corporation (72) Inventor Akira Ogiso 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Chemicals Inc. (72) Inventor Taizo Nishimoto 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Inside of Mitsui Chemicals Co., Ltd. EA22 EA25 EA32 EA43 FA01 FA12 FB42 4C056 AA01 AB01 AC02 AD03 AE03 CA06 CA09 5D029 JA04 JB47

Claims (3)

[Claims] 1. An optical recording medium having at least a recording layer and a reflective layer on a substrate, wherein the recording layer has the general formula (1)
An optical recording medium containing a compound represented by the formula: Embedded image [Wherein, R _{1 to} R ₈ are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 20 or less carbon atoms,
Represents an alkoxy group, an alkylthio group, an aryloxy group, an arylthio group, an alkenyl group, an aralkyl group, an acyl group, an aryl group, a heteroaryl group, or an alkylsulfonic acid group; X represents an oxygen atom or a sulfur atom; Represents a substituted or unsubstituted aryl group or heteroaryl group having the number of 20 or less. ] 2. A of the compound represented by the general formula (1) is:
The optical recording medium according to claim 1, which is a substituted or unsubstituted phenyl group, naphthyl group, furyl group, pyrrolyl group, or thienyl group. 3. The optical recording medium according to claim 1, wherein recording and reproduction can be performed with respect to a laser beam selected from a wavelength range of 400 nm to 500 nm.