JP2005297280A - Optical recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording material in an optical recording medium in a write-once type DVD disc system corresponding to high speed writing-in. <P>SOLUTION: In the optical recording medium, at least one chelate compound consisting of azo compounds represented by general formula (I), bivalent metal salts and the like in the recording medium. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a high-capacity write once optical disk for data (large-capacity write-once compact disk, DVD-R), and more particularly to a recording material that can cope with high-speed writing by a recording layer mainly composed of a dye having a specific structure.

  Currently, DVD-R is being developed as a next-generation large-capacity optical disk. Factors for improving the recording capacity are the development of recording materials for miniaturization of recording pits, the use of image compression techniques such as MPEG2, and the development of descriptions such as shortening the wavelength of semiconductor lasers for reading recording pits.

  Up to now, only 670 nm AlGaInP laser diodes have been developed and commercialized for bar code readers and measuring instruments as red wavelength semiconductor lasers. Lasers are being used in earnest in the optical storage market. In the case of a DVD drive, the light source is standardized with two wavelengths of a laser diode in a 635 nm band and a 650 nm band. For high-density recording, it is desirable that the wavelength is shorter, and the wavelength of 635 nm is preferable as a drive for additional recording media. On the other hand, the read-only DVD-ROM drive is commercialized with a wavelength of ˜650 nm.

  Under such circumstances, the most preferable DVD-R media is a medium (DVD-R) that can record and reproduce at a wavelength up to 635 nm and can reproduce at a wavelength up to 650 nm. An excellent recording material that can be recorded and reproduced by an optical pickup using a laser of 650 nm or less is desired.

As a technical document filed prior to the present invention, an optical storage medium suitable for high-density recording capable of recording and reproduction with a short wavelength laser having a wavelength of 520 to 690 nm and a recording layer material therefor (Patent Document 1) An optical information recording medium that maintains high light resistance even when stored in a harsh environment such as high temperature and high humidity (Patent Document 2), a high-density optical disk system that uses a semiconductor laser having an oscillation wavelength at a shorter wavelength (DVD) There are optical recording media (Patent Document 3 and Patent Document 4) excellent in light resistance and storage stability suitable for -R).
Japanese Patent Laid-Open No. 10-287819 JP-A-10-235999 JP 2002-11950 A JP 2002-11953 A

  However, DVD + R and DVD-R are currently commercialized as large-capacity optical disks. DVD-based optical discs can also be expected from the market to require high-speed writing as found in CD-Rs, but there is a problem that a recording material corresponding to high-speed writing has not yet been developed.

  The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to provide a recording material in an optical recording medium in a write-once DVD disc system that supports high-speed writing.

  As a result of studies by the present inventors, it has been found that the recording layer mainly composed of a dye having a specific structure can be applied to a write-once DVD disc system compatible with high-speed writing.

  In order to solve the above-mentioned problems, an invention according to claim 1 is an optical recording medium in which a recording layer is provided on a substrate, and an azo compound represented by the formula (1) and a divalent metal in the recording medium. An optical recording medium containing at least one chelate compound produced from a salt or the like is characterized.

（前記式（１）において、環Ａは隣接する窒素原子と一緒になって環を形成する複素５員環を表し、Ｒ₁〜Ｒ₆はそれぞれ独立に水素原子、ハロゲン原子、ニトロ基、シアノ基、水酸基、カルボキシ基、アミノ基、置換もしくは未置換のアルキル基、置換もしくは未置換のアリール基、置換もしくは未置換のアルキルオキシ基、置換もしくは未置換のアリールオキシ基、置換もしくは未置換のアルキルアミノ基、置換もしくは未置換のアリールアミノ基、置換もしくは未置換のアルキルカルボニルアミノ基、置換もしくは未置換のアリールカルボニルアミノ基、カルバモイル基、置換もしくは未置換のアルキルカルバモイル基、置換もしくは未置換のアリールカルバモイル基、アルキルスルホニルアミノ基、アリールスルホニルアミノ基を表す。尚、Ｒ₃とＲ₄は、連結して環を形成していても良い。）

(In the formula (1), ring A represents a hetero 5-membered ring which forms a ring together with an adjacent nitrogen atom, and R _{1 to} R ₆ each independently represents a hydrogen atom, a halogen atom, a nitro group, cyano. Group, hydroxyl group, carboxy group, amino group, substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted alkyloxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkyl Amino group, substituted or unsubstituted arylamino group, substituted or unsubstituted alkylcarbonylamino group, substituted or unsubstituted arylcarbonylamino group, carbamoyl group, substituted or unsubstituted alkylcarbamoyl group, substituted or unsubstituted aryl Represents a rucarbamoyl group, alkylsulfonylamino group, arylsulfonylamino group . Incidentally, R ₃ and R ₄ are linked to may form a ring.)

  The invention according to claim 2 is characterized in that the azo compound forming the chelate compound according to claim 1 is an optical recording medium represented by the formula (2).

（式（２）において、Ｒ₇〜Ｒ₁₄はそれぞれ独立に水素原子、ハロゲン原子、ニトロ基、シアノ基、水酸基、カルボキシル基、アミノ基、置換もしくは未置換のアルキル基、置換もしくは未置換のアリール基、置換もしくは未置換のアルキルオキシ基、置換もしくは未置換のアリールオキシ基、置換もしくは未置換のアルキルアミノ基、置換もしくは未置換のアリールアミノ基、置換もしくは未置換のアルキルカルボニルアミノ基、置換もしくは未置換のアリールカルボニルアミノ基、カルバモイル基、置換もしくは未置換のアルキルカルバモイル基、置換もしくは未置換のアリールカルバモイル基、アルキルスルホニルアミノ基、アリールスルホニルアミノ基、置換もしくは未置換のアルキルカルボニル基、置換もしくは未置換のアリールカルボニル基、アルキルスルホニル基、アリールスルホニル基を表し、尚、Ｒ₉とＲ₁₀、Ｒ₁₃とＲ₁₄は、連結して環を形成していても良い。）

(In the formula (2), R _{7 to} R ₁₄ are each independently a hydrogen atom, halogen atom, nitro group, cyano group, hydroxyl group, carboxyl group, amino group, substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group. Group, substituted or unsubstituted alkyloxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkylamino group, substituted or unsubstituted arylamino group, substituted or unsubstituted alkylcarbonylamino group, substituted or Unsubstituted arylcarbonylamino group, carbamoyl group, substituted or unsubstituted alkylcarbamoyl group, substituted or unsubstituted arylcarbamoyl group, alkylsulfonylamino group, arylsulfonylamino group, substituted or unsubstituted alkylcarbonyl group, substituted or Unsubstituted aryl Carbonyl group, an alkylsulfonyl group, an arylsulfonyl group, still, R ₉ and R _10, R ₁₃ and R ₁₄ are linked to may form a ring.)

  According to a third aspect of the present invention, there is provided an optical recording medium wherein the azo compound forming the chelate compound according to the first aspect is represented by the formula (3).

（式（３）において、Ｒ₁₅〜Ｒ₂₀はそれぞれ独立に水素原子、ハロゲン原子、ニトロ基、シアノ基、水酸基、カルボキシ基、アミノ基、置換もしくは未置換のアルキル基、置換もしくは未置換のアリール基、置換もしくは未置換のアルキルオキシ基、置換もしくは未置換のアリールオキシ基、置換もしくは未置換のアルキルアミノ基、置換もしくは未置換のアリールアミノ基、置換もしくは未置換のアルキルカルボニルアミノ基、置換もしくは未置換のアリールカルボニルアミノ基、カルバモイル基、置換もしくは未置換のアルキルカルバモイル基、置換もしくは未置換のアリールカルバモイル基、アルキルスルホニルアミノ基、アリールスルホニルアミノ基、置換もしくは未置換のアルキルカルボニル基、置換もしくは未置換のアリールカルボニル基、アルキルスルホニル基、アリールスルホニル基を表し、尚、Ｒ₁₇とＲ₁₈は、連結して環を形成していても良い。）

(In the formula (3), R _{15 to} R ₂₀ are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxy group, an amino group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group. Group, substituted or unsubstituted alkyloxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkylamino group, substituted or unsubstituted arylamino group, substituted or unsubstituted alkylcarbonylamino group, substituted or Unsubstituted arylcarbonylamino group, carbamoyl group, substituted or unsubstituted alkylcarbamoyl group, substituted or unsubstituted arylcarbamoyl group, alkylsulfonylamino group, arylsulfonylamino group, substituted or unsubstituted alkylcarbonyl group, substituted or Unsubstituted aryl A sulfonyl group, an alkylsulfonyl group, and an arylsulfonyl group, wherein R ₁₇ and R ₁₈ may be linked to form a ring.)

  According to a fourth aspect of the present invention, in the chelate compound according to the first to third aspects, an optical recording medium in which the metal atom is an atom selected from nickel or copper.

  According to a fifth aspect of the present invention, in the optical recording medium according to any one of the first to fourth aspects, the refractive index n of the recording layer single layer with respect to light in the wavelength region of the recording / reproducing wavelength ± 10 nm is 1.5. It is characterized by an optical recording medium in which ≦ n ≦ 3.0 and the extinction coefficient k is 0.02 ≦ k ≦ 0.2.

  According to a sixth aspect of the present invention, in the optical recording medium according to any one of the first to fifth aspects, in the thermogravimetric analysis of the organic dye, the slope of the weight loss with respect to the temperature in the main weight loss process is 2% / ° C. The above-described optical recording medium is characterized.

  The invention according to claim 7 is the optical recording medium according to any one of claims 1 to 5, wherein the total weight loss in the main weight loss process is 30% or more and the weight loss is determined by thermogravimetric analysis of the organic dye. An optical recording medium having a starting temperature of 350 ° C. or lower is characterized.

  The invention according to claim 8 is the optical recording medium according to any one of claims 1 to 7, wherein the track pitch on the substrate is 0.7 to 0.8 μm, the groove width is a half width, It is characterized by an optical recording medium of 0.18 to 0.36 μm.

  According to the present invention, in an optical recording medium in which a recording layer is provided on a substrate, the recording medium contains at least one chelate compound generated from the azo compound of formula (1) and a divalent metal salt. By configuring the optical recording medium characterized by the basic structure of the optical recording medium, it is possible to obtain an optical recording medium that can stably and inexpensively supply a compound and improve optical characteristics.

In the formula (1), ring A represents a hetero 5-membered ring that forms a ring together with an adjacent nitrogen atom, and R _{1 to} R ₆ each independently represent a hydrogen atom, a halogen atom, a nitro group, or a cyano group. , Hydroxyl group, carboxy group, amino group, substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted alkyloxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkylamino Group, substituted or unsubstituted arylamino group, substituted or unsubstituted alkylcarbonylamino group, substituted or unsubstituted arylcarbonylamino group, carbamoyl group, substituted or unsubstituted alkylcarbamoyl group, substituted or unsubstituted arylcarbamoyl Represents a group, an alkylsulfonylamino group, an arylsulfonylamino group R ₃ and R ₄ may be linked to form a ring.

  In addition, by limiting the azo compound to a specific indole structure or a specific indazole structure, the optimal structure of an information recording medium using a chelate compound which can be synthesized inexpensively and easily and has excellent optical properties and thermal decomposition behavior Can be obtained.

  Further, in the chelate compound, when the metal atom is an atom selected from nickel or copper, it is possible to obtain an optimum structure for achieving high stability of the recording medium.

  The refractive index n of the recording layer single layer with respect to light in the wavelength range of the recording / reproducing wavelength ± 10 nm is 1.5 ≦ n ≦ 3.0, and the extinction coefficient k is 0.02 ≦ k ≦ 0.2. The characteristic optical recording medium can provide an optimum structure of the recording medium that achieves a high refractive index, and can be recorded and reproduced with a laser beam having a wavelength of 690 nm or less, and has excellent light resistance and storage stability. It is possible to provide an information recording medium capable of recording / reproducing with a stable high reflectivity and high degree of modulation.

  Further, in the thermogravimetric analysis of the organic dye, due to the optical characteristics of the azo metal chelate compound of the optical recording medium, the inclination of the weight loss with respect to the temperature in the main weight loss process is 2% / ° C. or more. Recording medium capable of high density recording with low jitter by an optical recording medium characterized in that the total weight loss in the main weight loss process is 30% or more and the weight loss starting temperature is 350 ° C. or less. Can be obtained.

  Furthermore, stable recording and reproduction can be achieved by an optical recording medium characterized in that the track pitch on the substrate is 0.7 to 0.8 μm and the groove width is a half-value width of 0.18 to 0.36 μm. A possible information recording medium can be obtained.

In formula (1), ring A represents a hetero 5-membered ring that forms a ring together with an adjacent nitrogen atom, and R _{1 to} R ₆ each independently represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, Hydroxyl group, carboxy group, amino group, substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted alkyloxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkylamino group Substituted or unsubstituted arylamino group, substituted or unsubstituted alkylcarbonylamino group, substituted or unsubstituted arylcarbonylamino group, carbamoyl group, substituted or unsubstituted alkylcarbamoyl group, substituted or unsubstituted arylcarbamoyl group Represents an alkylsulfonylamino group or an arylsulfonylamino group. R ₃ and R ₄ may be linked to form a ring.
Specific examples of the halogen atom include fluorine, chlorine, bromine and iodine.
Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n -Primary alkyl group such as decyl group, isobutyl group, isoamyl group, 2-methylbutyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, 2-ethylbutyl group, 2-methylhexyl group, 3 -Methylhexyl group, 4-methylhexyl group, 5-methylhexyl group, 2-ethylpentyl group, 3-ethylpentyl group, 2-methylheptyl group, 3-methylheptyl group, 4-methylheptyl group, 5-methyl Heptyl, 2-ethylhexyl, 3-ethylhexyl, isopropyl, sec-butyl, 1-ethylpropyl, 1-methylbutyl, 1,2-di Tylpropyl group, 1-methylheptyl group, 1-ethylbutyl group, 1,3-dimethylbutyl group, 1,2-dimethylbutyl group, 1-ethyl-2-methylpropyl group, 1-methylhexyl group, 1-ethylheptyl Group, 1-propylbutyl group, 1-isopropyl-2-methylpropyl group, 1-ethyl-2-methylbutyl group, 1-ethyl-2-methylbutyl group, 1-propyl-2-methylpropyl group, 1-methylheptyl Group, 1-ethylhexyl group, 1-propylpentyl group, 1-isopropylpentyl group, 1-isopropyl-2-methylbutyl group, 1-isopropyl-3-methylbutyl group, 1-methyloctyl group, 1-ethylheptyl group, 1 Secondary alkyl groups such as -propylhexyl group, 1-isobutyl-3-methylbutyl group, neopentyl group, tert- Tertiary alkyl group such as til group, tert-hexyl group, tert-amyl group, tert-octyl group, cyclohexyl group, 4-methylcyclohexyl group, 4-ethylcyclohexyl group, 4-tert-butylcyclohexyl group, 4- ( And cycloalkyl groups such as 2-ethylhexyl) cyclohexyl group, bornyl group, and isobornyl group (adamantane group).

  Further, these primary and secondary alkyl groups are substituted with a hydroxyl group, a halogen atom, a nitro group, a carboxy group, a cyano group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic residue, and the like. In addition, the alkyl group may be substituted with an atom such as oxygen, sulfur, or nitrogen. Examples of the alkyl group substituted through oxygen include methoxymethyl group, methoxyethyl group, ethoxymethyl group, ethoxyethyl group, butoxyethyl group, ethoxyethoxyethyl group, phenoxyethyl group, methoxypropyl group, ethoxypropyl group, As an alkyl group in which a piperidino group, a morpholino group, or the like is substituted through sulfur, a methylthioethyl group, an ethylthioethyl group, an ethylthiopropyl group, a phenylthioethyl group, or the like is substituted through nitrogen Examples of the alkyl group include a dimethylaminoethyl group, a diethylaminoethyl group, and a diethylaminopropyl group. Specific examples of the heterocyclic residue include indolyl group, furyl group, thienyl group, pyridyl group, piperidyl group, quinolyl group, isoquinolyl group, piperidino group, morpholino group, pyrrolyl group and the like.

  Specific examples of the aryl group include a phenyl group, a pentarenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptaenyl group, a biphenylenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, and a pyrenyl group.

  Specific examples of the alkenyl group include vinyl group, allyl group, isopropenyl group, 1-butenyl group, 1-methyl-1-propenyl group, 2-methyl-1-propenyl group, 1,3-butadienyl group, 1- Butene-3-ynyl group, 1-pentenyl group, 1-methyl-1-butenyl group, 2-methyl-1-butenyl group, 3-methyl-1-butenyl group, 1-2-dimethyl-1-butenyl group, Examples include a 2,2-dimethyl-1-butenyl group, a 1,3-pentadienyl group, a 1,4-pentadienyl group, a 1-pentene-3-ynyl group, and a 1-pentene-4-ynyl group.

  Specific examples of the alkyloxy group are not particularly limited as long as a directly substituted or unsubstituted alkyl group is bonded to an oxygen atom, and specific examples of the alkyl group include the above-described specific examples.

  Specific examples of the aryloxy group may be those in which a substituted or unsubstituted aryl group is bonded directly to an oxygen atom. Specific examples of the aryl group include the above-described specific examples. Can do.

  Specific examples of the alkylamino group are not particularly limited as long as a directly substituted or unsubstituted alkyl group is bonded to the nitrogen atom, and specific examples of the alkyl group include the above-described specific examples.

  Specific examples of the arylamino group may be those in which a directly substituted or unsubstituted aryl group is bonded to a nitrogen atom. Specific examples of the aryl group include the above-described specific examples. Can do.

  Specific examples of the alkylcarbonylamino group may be those in which a directly substituted or unsubstituted alkyl group is bonded to a carbon atom of the carbonylamino group, and specific examples of the alkyl group include the specific examples described above. Can do.

  Specific examples of the arylcarbonylamino group are not particularly limited as long as a directly substituted or unsubstituted aryl group is bonded to the carbon atom of the carbonylamino group. Specific examples can be given.

Specific examples of the alkylcarbamoyl group may be those in which a hydrogen atom, a substituted or unsubstituted alkyl group is bonded directly and independently to a nitrogen atom of the carbamoyl group, and specific examples of the alkyl group include those described above. Specific examples can be given.
Specific examples of the arylcarbamoyl group may be those in which a hydrogen atom, a substituted or unsubstituted aryl group is directly and independently bonded to a nitrogen atom of the carbamoyl group. The above-mentioned specific examples can be given as examples.

  Specific examples of the alkylsulfonylamino group are not particularly limited as long as a directly substituted or unsubstituted alkyl group is bonded to the sulfur atom, and specific examples of the alkyl group include the above-described specific examples.

  Specific examples of the arylsulfonylamino group may be those in which a substituted or unsubstituted aryl group is bonded directly to the sulfur atom, and examples of the aryl include the above-described specific examples. Can do.

  Specific examples of the alkylcarbonyl group may be those in which a directly or unsubstituted alkyl group is bonded to a carbon atom of the carbonyl group, and specific examples of the alkyl group may include the above-described specific examples. .

  Specific examples of the aryl carbonyl group may be those in which a substituted or unsubstituted aryl group is bonded directly to a carbon atom of the carbonyl group. Specific examples of the aryl group include the above-mentioned specific examples. An example can be given.

  Specific examples of the alkylsulfonyl group may be those in which a substituted or unsubstituted alkyl group is bonded directly to the sulfur atom of the sulfonyl group, and specific examples of the alkyl group may include the above-described specific examples. .

  Specific examples of the arylsulfonyl group may be those in which a substituted or unsubstituted aryl group is bonded directly to the sulfur atom of the sulfonyl group. Specific examples of the aryl group include the above-described specific examples. An example can be given.

In formula (2), R _{7 to} R ₁₄ are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxy group, an amino group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group. Group, substituted or unsubstituted alkyloxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkylamino group, substituted or unsubstituted arylamino group, substituted or unsubstituted alkylcarbonylamino group Substituted or unsubstituted arylcarbonylamino group, carbamoyl group, substituted or unsubstituted alkylcarbamoyl group, substituted or unsubstituted arylcarbamoyl group, alkylsulfonylamino group, arylsulfonylamino group, substituted or unsubstituted Substituted alkylcarbonyl group, substituted or unsubstituted arylalkyl Group, an alkylsulfonyl group, ant - represents a Rusuruhoniru group still, R ₉ and R _10, R ₁₃ and R ₁₄ are linked to may form a ring.
Specific examples of the substituent are the same as those described above.

In the formula (3), R _{15 to} R ₂₀ are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxy group, an amino group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group. Group, substituted or unsubstituted alkyloxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkylamino group, substituted or unsubstituted arylamino group, substituted or unsubstituted alkylcarbonylamino group Substituted or unsubstituted arylcarbonylamino group, carbamoyl group, substituted or unsubstituted alkylcarbamoyl group, substituted or unsubstituted arylcarbamoyl group, alkylsulfonylamino group, arylsulfonylamino group, substituted or unsubstituted Substituted alkylcarbonyl group, substituted or unsubstituted arylalkyl It represents a bonyl group, an alkylsulfonyl group, or an arylsulfonyl group, and R ₁₇ and R ₁₈ may be linked to form a ring. Specific examples of the substituent are the same as those described above.

  The production method of the azo compound and metal chelate compound of the present invention will be described. For example, Inoue Chem. Lett. , 1981, 1733-1736. In addition, about a manufacturing method, it is not limited to the following method. That is, Formula 4 can be obtained by reacting 2,4,6-trichloro-1,3,5-triazine (cyanuric chloride) and benzenethiol in ethanol. Subsequently, Formula 5 can be obtained by making Formula 4 and hydrazine act in ethanol.

  Next, the azo compound of the formula (7) can be obtained by reacting the formula (5) and the formula (6) in the presence of potassium ferricyanide in an acetic acid aqueous solution.

  According to the above method, the azo compound represented by the formula (1) can be synthesized.

  In claim 1, as a heterocyclic ring constituting the formula (1), a chelate compound comprising an indole represented by the formula (2) and an indazole represented by the formula (3) is easily available. Therefore, it became clear that it was useful.

  The azo compound shown in claims 1 to 3 easily forms a chelate compound by acting with a divalent metal salt or the like. It has been clarified that these chelate compounds can be used as recording materials for write-once DVDs and have physical properties that can cope with high linear velocity recording.

  For production of the chelate compound, the azo-substituted indazole compound shown in claims 1 to 3 and a divalent metal salt or the like are added to a solvent such as methanol, DMF, or glycerin. In some cases, an alkali component such as a sodium hydroxide solution or aqueous ammonia may be added, or the temperature may be raised to a temperature between room temperature and the boiling point of the solvent.

  Specific examples of the divalent metal atom include manganese, iron, cobalt, nickel, copper, and zinc. Particularly, nickel and copper chelate compounds are excellent in optical properties such as light resistance and refractive index as optical recording materials.

  Next, the configuration of the recording medium. Optical characteristics and thermal characteristics are raised as items necessary for constituting the recording layer. The necessary conditions for the optical characteristics are that the recording / reproducing wavelength has a large absorption band on the short wavelength side from 630 nm to 690 nm and the recording / reproducing wavelength is in the vicinity of the long wavelength end of the absorption band. . This means that it has a large refractive index and extinction coefficient at a recording / reproducing wavelength of 630 nm to 690 nm.

  Specifically, the refractive index n of the single recording layer with respect to light in the wavelength range near the long wavelength near the recording / reproducing wavelength is 1.5 or more and 3.0 or less, and the extinction coefficient k is 0.02 or more and 0.2. It is preferable to be in the following range. When n is less than 1.5, it is difficult to obtain a sufficient optical change, so the recording modulation degree is low, which is not preferable. When n exceeds 3.0, the wavelength dependency is too high. Even in the recording / reproducing wavelength region, an error occurs. Further, when k is less than 0.02, the recording sensitivity is deteriorated, which is not preferable. When k is more than 0.2, it is difficult to obtain a reflectance of 50% or more.

  Thermally necessary conditions are that weight loss in the main weight loss process in thermogravimetric analysis needs to be abrupt with respect to temperature. This is because the organic material film is decomposed by the main weight reduction process, causing a decrease in film thickness and a change in optical constant, thereby forming a recording portion in an optical sense. Therefore, when the weight loss in the main weight loss process is moderate with respect to the temperature, this is formed over a wide temperature range, which is extremely disadvantageous when forming a high-density recording portion. For the same reason, the use of a material having a plurality of weight loss processes is also disadvantageous for high density.

  In the present invention, among several weight loss processes, the one having the largest weight loss rate is called a main weight loss process. In the present invention, the weight loss slope is determined as follows.

The organic material having a weight of m0 is heated at 10 ° C./min in a nitrogen atmosphere. As the temperature rises, the weight of the organic material decreases by a small amount, indicating a weight loss line (almost straight line ab). When a certain temperature is reached, the organic material undergoes a rapid weight loss and a weight loss approximately along the straight line cd. This is the main weight loss process. When the temperature is further increased, the rapid mass reduction ends, and the weight is reduced substantially along the straight line ef.
Now, the temperature at the intersection of the straight line ab and the straight line cd is T1 (° C.), the residual weight loss rate with respect to the initial weight m0 is m1 (%), and the temperature at the intersection of the straight line cd and the straight line ef Is T2 (° C.), and the residual weight loss rate with respect to the initial mass m0 is m2 (%). The sudden weight loss start temperature is T1, the rapid weight loss end temperature is T2, and the slope of weight loss when sudden weight loss is manifested is
The following formula:
(M1-m2) (%) / (T2-T1) (° C.)
The weight loss rate with respect to the initial weight is represented by (m1-m2) (%).
In FIG. 1, “TG%” represents the weight loss rate of the organic compound to be measured. The mass m0 of the organic compound before the temperature rise is expressed as 100%, and the state where there is no substance in the measuring instrument is 0%.

Based on the above definition, the recording material used for the optical information recording medium preferably has a weight loss gradient of 2% / ° C. or more in the main weight loss process. Use of a recording material having a weight loss gradient of less than 2% / ° C. is unsuitable for an information recording medium because the recording portion becomes large and it becomes difficult to form a short recording portion.
The weight reduction rate in the main weight loss process is preferably 30% or more. If it is less than 30%, good recording modulation degree and recording sensitivity may not be obtained.

  Further, the necessary condition for the thermal characteristics is that the weight start temperature T1 is in a certain temperature range. Specifically, the weight loss starting temperature is 350 ° C. or lower, preferably in the range of 200 to 350 ° C. When the weight loss starting temperature is 350 ° C. or higher, the power of the recording laser light is increased and is not practical, and when it is 200 ° C. or lower, the recording stability is deteriorated such as reproduction deterioration.

  The necessary conditions for the substrate shape are a track pitch on the substrate of 0.7 to 0.8 μm, a groove width of half width, and 0.18 to 0.36 μm. The substrate usually has guide grooves with a depth of 1000 to 2500 mm. The track pitch is usually 0.7 to 1.0 μm, but 0.7 to 0.8 μm is preferable for high capacity use. The groove width is preferably 0.18 to 0.36 [mu] m in half width. If it is less than 0.18 μm, it may be difficult to obtain a sufficient tracking error signal intensity. On the other hand, if it exceeds 0.36 μm, the recording part tends to spread laterally when recording is not preferable.

(Structure of the recording medium)
The recording material of the present invention is a CD-R for the CD-R comprising the structure shown in FIG. 3 (which may be a so-called air-sandwich or two-piece bonding structure shown in FIG. A media structure may be used.

(Necessary characteristics and constituent materials of each layer)
The structure of the recording medium of the present invention has a basic structure in which the first substrate and the second substrate are bonded together with an adhesive via a recording layer. The recording layer may be a single organic dye layer, or may be a laminate of an organic dye layer and a metal reflective layer in order to increase reflectivity. The recording layer and the substrate may be formed through an undercoat layer or a protective layer, or may be laminated to improve the function. The most commonly used is the first substrate / organic dye layer / metal reflective layer / protective layer / adhesive layer / second substrate structure.

(substrate)
As a necessary characteristic of the substrate, it must be transparent to the laser beam used only when recording / reproducing is performed from the substrate side, and the substrate does not have to be transparent when recording / reproducing is performed from the recording layer side. Therefore, in the present invention, when only one layer is used, if only the second substrate described in the claims is transparent, the first transparent and opaque are not questioned.

  As the substrate material, for example, polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, polyimide or other plastic, glass, ceramic, metal, or the like can be used. When only one layer is used, or when two substrates are used in a sandwich shape, tracking guide grooves and guide pits on the surface of the first substrate according to the claims and a pre-format for address signals and the like are provided. A mat must be formed.

(Middle layer)
A layer provided other than the substrate, the recording layer, the reflective layer, and the protective layer including the undercoat layer is referred to as an intermediate layer herein. This intermediate layer has (a) improved adhesion, (b) a barrier such as water or gas, (c) improved storage stability of the recording layer, (d) improved reflectance, (e) from the solvent. It is used for the purpose of protecting the substrate and the recording layer, (f) formation of guide grooves, guide pits, preforms, etc. For the purpose of (a), polymer materials such as ionomer resins, polyamide resins, vinyl resins, natural resins, natural polymers, silicones, various polymer substances such as liquid rubber, and silane couplings For the purposes of (b) and (c), in addition to the polymer material, inorganic compounds such as SiO ₂ , MgF ₂ , SiO, TiO ₂ , ZnO, TiN, SiN and other metals Or a semimetal such as Zn, Cu, Ni, Cr, Ge, Se, Au, Ag, Al, or the like can be used. For the purpose of (d), metals such as Al and Ag, and organic thin films having metallic luster such as methine dyes and xanthene dyes can be used. For the purposes of (e) and (f) In contrast, an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used. The thickness of the undercoat layer is 0.01 to 30 μm, preferably 0.05 to 10 μm.

  The substrate to be used must be transparent to the laser used only when recording and reproduction are performed from the substrate side, and the substrate does not have to be transparent when recording and reproduction are performed from the recording layer side. As the substrate material, for example, plastic such as polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, polyimide, glass, ceramic, metal, or the like can be used. A tracking guide groove, guide pits, and a pre-format such as an address signal may be formed on the surface of the substrate.

(Recording layer)
The recording layer causes some optical change by laser light irradiation, and can record information by the change. The recording layer needs to contain the dye of the present invention. In forming the recording layer, the dye of the present invention may be used alone or in combination of two or more. Furthermore, the dye of the present invention may be mixed or laminated with other organic dyes, metals and metal compounds for the purpose of improving optical characteristics, recording sensitivity, signal characteristics and the like. Examples of organic dyes include polymethine dyes, naphthalocyanine, phthalocyanine, squarylium, croconium, pyrylium, naphthoquinone, anthroquinone (indanthrene), xanthene, triphenylmethane, azulene, tetre Examples thereof include hydrocholine-based, phenanthrene-based, triphenothiazine-based dyes, metal chelate compounds, and the like, and the above dyes may be used alone or in combination of two or more.

In addition, a metal, a metal compound such as In, Te, Bi, Se, Sb, Ge, Sn, Al, Be, TeO ₂ , SnO, As, Cd, etc. may be used in a dispersed or mixed form in the dye. You can also. Further, various materials such as ionomer resins, polyamide resins, vinyl resins, natural polymers, silicones, liquid rubbers, or silane coupling agents are dispersed and mixed in the dye. Alternatively, it may be used together with a stabilizer (for example, a transition metal complex), a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer and the like for the purpose of improving characteristics.

  The recording layer can be formed by ordinary means such as vapor deposition, sputtering, CVD or solution coating. In the case of using the coating method, the dye is dissolved in an organic solvent or the like, and a conventional coating method such as spraying, roller coating, dipping or spin coating is performed.

  As the organic solvent used, alcohols such as methanol, ethanol and isopropanol, ketones such as acetone, methyl ethyl ketone and cyclohexanone, N, N-dimethylformamide, N, N-dimethylacetamide and the like are generally used. Amides, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, diethyl ether, ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, chloroform, methylene chloride, dichloroethane, tetrachloride Aliphatic halogenated hydrocarbons such as carbon and trichloroethane, or aromatics such as benzene, xylene, monochlorobenzene and dichlorobenzene, cellosolves such as methoxyethanol and ethoxyethanol, hexane, pentane and cyclohexane Hexane, it can be used hydrocarbons such as methylcyclohexane. The film thickness of the recording layer is 100 to 10 μm, preferably 200 to 2000 μm.

(Metal reflective layer)
Examples of the reflective layer include a metal, a semi-metal, and the like that are highly resistant to corrosion and are not easily corroded, and examples of materials include Au, Ag, Cr, Ni, Al, Fe, Sn, etc. Au, Ag, and Al are most preferable from the viewpoint of the properties, and these metals and metalloids may be used alone or as two kinds of alloys.

  Examples of the film forming method include vapor deposition and sputtering, and the film pressure is 50 to 5000 mm, preferably 100 to 3000 mm.

(Protective layer, substrate surface hard coat layer)
The protective layer or the substrate surface hard coat layer (a) protects the recording layer (reflection / absorption layer) from scratches, dust, dirt, etc. (b) improves the storage stability of the recording layer (reflection / absorption layer). (C) It is used for the purpose of improving the reflectance. For these purposes, the materials shown in the intermediate layer can be used. In addition, SiO, SiO _{2 and the} like can be used as inorganic materials, and polymethyl acrylate, polycarbonate, epoxy resin, polystyrene, polyester resin, vinyl resin, cellulose, aliphatic as organic materials. Thermosoftening and heat melting resins such as hydrocarbon resins, aromatic hydrocarbon resins, natural rubber, styrene butadiene resins, chloroprene rubbers, waxes, alkyd resins, drying oils and rosins can also be used.

  Among the materials described above, the most preferable example for the protective layer or the substrate surface hard coat layer is an ultraviolet curable resin excellent in productivity. The film pressure of the protective layer or the substrate hard coat layer is 0.01 to 30 μm, preferably 0.05 to 10 μm. In the present invention, the lower intermediate layer, protective layer, and substrate side hard coat layer are the same as in the case of the recording layer, stabilizer, dispersant, flame retardant, lubricant, antistatic agent, surfactant, A plasticizer or the like can be contained.

(Example)
Examples are shown below, but the present invention is not limited to these examples.

(Synthesis Example 1)
2,4,6-trichloro-1,3,5-triazine and 2 equivalents of benzenethiol are dissolved in acetone, sodium carbonate is allowed to act while maintaining 0 ° C., and 2-chloro-4,6-di (Phenylthio) -1,3,5-triazine was obtained. This was dissolved in methanol, and hydrazine monohydrate was allowed to act while maintaining -10 ° C to obtain 2,4-di (phenylthio) -6-hydrazino-1,3,5-triazine.
This hydrazino compound and 4-diethylaminoindole were dissolved in methanol, and 35% hydrogen peroxide was allowed to act in the presence of iodine to obtain the desired azo compound.
Next, the azo compound was dissolved in DMF, and nickel acetate was allowed to act to obtain the target chelate compound (1) shown in the following compound examples.

(Synthesis Example 2)
2-Methyl-3-nitroaniline and ethyl iodide were allowed to act in DMF in the presence of potassium carbonate to obtain N, N-diethyl-2-methyl-3-nitroaniline. The nitro group was reduced with palladium / carbon to give 2-methyl-3-diethylaminoaniline. This was reacted with sodium nitrite in acetic acid to obtain 4-diethylaminoindazole.
Next, 2,4,6-trichloro-1,3,5-triazine and 2 equivalents of aniline are allowed to act in acetone to give 2-chloro-4,6-di (phenylamino) -1,3,5. -Triazine was obtained. This was dissolved in methanol, and hydrazine monohydrate was allowed to act while maintaining -10 ° C to obtain 2,4-di (phenylamino) -6-hydrazino-1,3,5-triazine.
This hydrazino compound and 4-diethylaminoindazole were dissolved in an acetic acid aqueous solution and reacted with potassium ferricyanide to obtain the desired azo compound.
Next, the azo compound was dissolved in DMF, and copper chloride was allowed to act to obtain the target chelate compound (2) shown below.

(Example 1)
A guide groove having a depth of 1650 mm, a half-value width of 0.25 μm, and a track pitch of 0.74 μm is formed on a 0.6 mm thick injection-molded polycarbonate substrate by a photopolymer. , 2,2-tetrafluoropropanol solution is applied to a spinner to form a recording layer having a thickness of 800 mm, and then a reflective layer having a thickness of 1000 mm is formed by sputtering, and an acrylic photopolymer is formed thereon. After a protective layer having a thickness of 7 μm was formed, an injection molded polycarbonate flat substrate having a thickness of 0.6 mm was adhered with an acrylic photopolymer to obtain a recording medium.

(Examples 2 to 15)
A recording medium was formed in exactly the same manner as in Example 1, except that the compounds (2) to (15) were used instead of the compound (1) in Example 1.

(Recording conditions)
A semiconductor laser beam having a laser oscillation wavelength of 658 nm and a beam diameter of 1.0 μm was recorded on this recording medium, and an EFM signal (linear velocity: 14 m / sec.) Was recorded while tracking to obtain a semiconductor laser having an oscillation wavelength of 670 nm. -Reproduction with continuous light (reproduction power: 0.7 mW) and observation of the reproduction waveform.

(Weatherproof test conditions)
The weather resistance test was conducted under the following conditions.
Light resistance test: 50,000 Lux, Xe light, 20-hour continuous irradiation storage test: 60 ° C., 90%, left for 600 hours Evaluation results are shown in Table 1.

It is explanatory drawing of the method of calculating | requiring the main weight loss process of the organic material of this invention, and a weight loss rate. It is a cross-sectional block diagram of a normal write-once type optical recording medium. 1 is a cross-sectional configuration diagram of a write-once optical disc of the present invention. It is a section lineblock diagram of a media medium for CD-R of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Recording layer 3 Undercoat layer 4 Protective layer 5 Hard coat layer 6 Metal reflective layer 7 Protective substrate 8 Adhesive layer

Claims (8)

In an optical recording medium comprising a recording layer on a substrate,
An optical recording medium comprising at least one chelate compound produced from an azo compound represented by the following formula (1) and a divalent metal salt in the recording medium.

(In Formula (1), Ring A represents a hetero 5-membered ring that forms a ring together with an adjacent nitrogen atom, and R _{1 to} R ₆ each independently represents a hydrogen atom, a halogen atom, a nitro group, or a cyano group. , Hydroxyl group, carboxy group, amino group, substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted alkyloxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkylamino Group, substituted or unsubstituted arylamino group, substituted or unsubstituted alkylcarbonylamino group, substituted or unsubstituted arylcarbonylamino group, carbamoyl group, substituted or unsubstituted alkylcarbamoyl group, substituted or unsubstituted arylcarbamoyl Represents a group, an alkylsulfonylamino group, and an arylsulfonylamino group. , R ₃ and R ₄ are linked to may form a ring.) An optical recording medium, wherein the azo compound forming the chelate compound according to claim 1 is represented by the following formula (2).

(In the formula (2), R _{7 to} R ₁₄ are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxy group, an amino group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group. Group, substituted or unsubstituted alkyloxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkylamino group, substituted or unsubstituted arylamino group, substituted or unsubstituted alkylcarbonylamino group, substituted or Unsubstituted arylcarbonylamino group, carbamoyl group, substituted or unsubstituted alkylcarbamoyl group, substituted or unsubstituted arylcarbamoyl group, alkylsulfonylamino group, arylsulfonylamino group, substituted or unsubstituted alkylcarbonyl group, substituted or Unsubstituted aryl Boniru group, an alkylsulfonyl group, an arylsulfonyl group, still, R ₉ and R _10, R ₁₃ and R ₁₄ are linked to may form a ring.) An optical recording medium, wherein the azo compound forming the chelate compound according to claim 1 is represented by the following formula (3).

(In the formula (3), R _{15 to} R ₂₀ are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxy group, an amino group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group. Group, substituted or unsubstituted alkyloxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkylamino group, substituted or unsubstituted arylamino group, substituted or unsubstituted alkylcarbonylamino group, substituted or Unsubstituted arylcarbonylamino group, carbamoyl group, substituted or unsubstituted alkylcarbamoyl group, substituted or unsubstituted arylcarbamoyl group, alkylsulfonylamino group, arylsulfonylamino group, substituted or unsubstituted alkylcarbonyl group, substituted or Unsubstituted aryl A sulfonyl group, an alkylsulfonyl group, and an arylsulfonyl group, wherein R ₁₇ and R ₁₈ may be linked to form a ring.)   4. The optical recording medium according to claim 1, wherein the metal atom is an atom selected from nickel or copper.   The optical recording medium according to any one of claims 1 to 4, wherein the refractive index n of the recording layer single layer with respect to light in the wavelength region of recording / reproducing wavelength ± 10 nm is 1.5 ≦ n ≦ 3.0, and extinction An optical recording medium, wherein the coefficient k is 0.02 ≦ k ≦ 0.2.   The optical recording medium according to any one of claims 1 to 5, wherein a gradient of weight loss with respect to temperature in the main weight loss process is 2% / ° C or more by thermogravimetric analysis of an organic dye. .   6. The optical recording medium according to claim 1, wherein the total weight loss in the main weight loss process is 30% or more and the weight loss start temperature is 350 ° C. or less by thermogravimetric analysis of the organic dye. An optical recording medium.   8. The optical recording medium according to claim 1, wherein the track pitch on the substrate is 0.7 to 0.8 [mu] m, and the groove width is a half value width of 0.18 to 0.36 [mu] m. A characteristic optical recording medium.

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