JP4137835B2 - Optical recording medium - Google Patents

Description

  The present invention relates to an optical recording medium (hereinafter also referred to as “optical information recording medium” or “information recording medium”) suitable for a write-once DVD disk system that supports high-speed writing.

  Conventionally, as a write-once type optical recording medium using a dye as a recording material in a recording layer, for example, a polymethine dye or a polymethine dye and a light stabilizer used as a recording material (see Patent Documents 1 and 2), tetraaza A layer comprising a porphyrin (porphyrazine) dye or cyanine dye, and an azo metal chelate dye (salt-forming dye) and a reflective layer (see Patent Documents 3 and 4), formazan (metal chelate) dye, and others Used as a recording material (see Patent Document 5), dipyrromethene (metal chelate) dye, and other dyes used as a recording material (see Patent Documents 6 and 7), having a maximum absorption wavelength at 550 to 650 nm. Various proposals such as squarylium compounds or squarylium metal chelate compounds (see Patent Documents 8 to 10) It has been made.

  Currently, write-once DVD media is being developed as a next-generation large-capacity optical disk, and further increases in recording capacity are being studied. Therefore, with the aim of increasing the recording capacity, development of recording materials for recording pit miniaturization, adoption of image compression technology represented by Moving Picture Experts Group-2 (MPEG2), and semiconductor laser for reading recording pits Technological developments such as shortening the wavelength of (LD) are underway.

  Therefore, the DVD-type optical disk is also required to be capable of high-speed writing like CD-R, high storage reliability, and excellent recording performance. An optical recording medium having such a capability has not been obtained yet, and it is desired to provide it promptly.

JP 2001-023235 A JP 2002-283722 A JP-A-10-856 JP 2002-83444 A JP 2002-283719 A JP 2002-83444 A JP 2002-117589 A JP 2001-322356 A JP 2002-234259 A JP 2002-370451 A

  This invention is made | formed in view of this present condition, and makes it a subject to solve the said various problems in the past and to achieve the following objectives. That is, an object of the present invention is to provide an optical recording medium suitable for a write-once DVD disc system that supports high-speed writing using a semiconductor laser.

  As a result of intensive studies by the present inventors in order to solve the above problems, an optical recording medium having a recording layer containing an azo metal chelate compound having a specific structure can be applied to a write-once DVD disc system compatible with high-speed writing. I found out.

ただし、前記構造式（１）中、Ｘは、カルコゲンから選択される原子を表す。環Ａは、隣接するＸ原子と窒素原子とが一緒になって形成される５員環を表し、該５員環は更に置換基で置換されていてもよい。Ｒ^１〜Ｒ^５は、互いに同一であってもよいし、異なっていてもよく、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、アルキル基、アリール基、アルケニル基、アルキルオキシ基、アリールオキシ基、アルキルアミノ基、アリールアミノ基、アルキルカルボニルアミノ基、アリールカルボニルアミノ基、カルバモイル基、アルキルカルバモイル基、アリールカルバモイル基、アルキルスルホニルアミノ基、及びアリールスルホニルアミノ基のいずれかを表し、これらは更に置換基で置換されていてもよく、Ｒ^１〜Ｒ^５の中で隣接するものどうしが互いに連結して環を形成していてもよい。Ｍは、金属原子を表す。ｎは、２〜３の整数を表す。
＜２＞ Ｒ^３が、下記構造式（２）で表される前記＜１＞に記載の光記録媒体である。

ただし、前記構造式（２）中、Ｒ^６及びＲ^７は、互いに同一であってもよいし、異なっていてもよく、水素原子、アルキル基、及びアリール基のいずれかを表し、これらは更に置換基により置換されていてもよく、互いに連結して環を形成していてもよい。
＜３＞ 環Ａが、下記構造式で表されるいずれかである前記＜１＞から＜２＞のいずれかに記載の光記録媒体である。

ただし、前記構造式中、Ｒ^８〜Ｒ^１４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、アルキル基、アリール基、アルケニル基、アルキルオキシ基、アリールオキシ基、アルキルアミノ基、アリールアミノ基、アルキルカルボニルアミノ基、アリールカルボニルアミノ基、カルバモイル基、アルキルカルバモイル基、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、アルキルカルボニル基、アリールカルボニル基、アルキルスルホニル基、及びアリールスルホニル基のいずれかを表し、これらは更に置換基で置換されていてもよく、Ｒ^８とＲ^９、Ｒ^１０とＲ^１１とは互いに連結して環を形成していてもよい。ｑは０〜４の整数を表し、ｑが２以上の場合には、隣接するものどうしが互いに連結して環を形成していてもよい。
＜４＞ 金属原子が、ニッケル及び銅のいずれかである前記＜１＞から＜３＞のいずれかに記載の光記録媒体である。
＜５＞ 記録層材料の熱重量分析における主減量過程での温度に対する減量の傾きが２％／℃以上である前記＜１＞から＜４＞のいずれかに記載の光記録媒体である。
＜６＞ 記録層材料の熱重量分析における主減量過程での総減量が３０％以上であり、かつ減量開始温度が３５０℃以下である前記＜１＞から＜５＞のいずれかに記載の光記録媒体である。
＜７＞ 記録再生波長±１０ｎｍの波長領域の光に対する記録層単層の屈折率ｎが１．５≦ｎ≦３．０であり、かつ消衰係数ｋが０．０２≦ｋ≦０．２である前記＜１＞から＜６＞のいずれかに記載の光記録媒体である。
＜８＞ 記録再生波長が６３０〜６９０ｎｍである前記＜７＞に記載の光記録媒体である。
＜９＞ 基板におけるトラックピッチが０．７〜０．８μｍであり、案内溝幅が半値幅で０．１８〜０．３６μｍである前記＜１＞から＜８＞のいずれかに記載の光記録媒体である。 The present invention is based on the above findings of the present inventors, and means for solving the above problems are as follows. That is,
<1> An optical recording medium comprising a substrate and at least a recording layer on the substrate, wherein the recording layer contains an azo metal chelate compound represented by the following structural formula (1).

In Structural Formula (1), X represents an atom selected from chalcogen. Ring A represents a 5-membered ring formed by combining an adjacent X atom and a nitrogen atom, and the 5-membered ring may be further substituted with a substituent. R ^{1 to} R ⁵ may be the same as or different from each other, and are a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxy group, an amino group, an alkyl group, an aryl group, or an alkenyl group. , Alkyloxy group, aryloxy group, alkylamino group, arylamino group, alkylcarbonylamino group, arylcarbonylamino group, carbamoyl group, alkylcarbamoyl group, arylcarbamoyl group, alkylsulfonylamino group, and arylsulfonylamino group These may be further substituted with a substituent, and adjacent ones of R ^{1 to} R ⁵ may be linked to each other to form a ring. M represents a metal atom. n represents an integer of 2 to 3.
<2> The optical recording medium according to <1>, wherein R ³ is represented by the following structural formula (2).

However, in the structural formula (2), R ⁶ and R ⁷ may be the same as or different from each other, and represent any one of a hydrogen atom, an alkyl group, and an aryl group. They may be substituted with a substituent, and may be linked to each other to form a ring.
<3> The optical recording medium according to any one of <1> to <2>, wherein ring A is any one of the following structural formulas.

However, in said structural formula, R < ⁸ > -R < ¹⁴ > is respectively independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxy group, an amino group, an alkyl group, an aryl group, an alkenyl group, an alkyloxy group, Aryloxy group, alkylamino group, arylamino group, alkylcarbonylamino group, arylcarbonylamino group, carbamoyl group, alkylcarbamoyl group, arylcarbamoyl group, alkylsulfonylamino group, arylsulfonylamino group, alkylcarbonyl group, arylcarbonyl group , An alkylsulfonyl group, and an arylsulfonyl group, which may be further substituted with a substituent, and R ⁸ and R ⁹ , R ¹⁰ and R ¹¹ are connected to each other to form a ring. May be. q represents an integer of 0 to 4, and when q is 2 or more, adjacent ones may be connected to each other to form a ring.
<4> The optical recording medium according to any one of <1> to <3>, wherein the metal atom is any one of nickel and copper.
<5> The optical recording medium according to any one of <1> to <4>, wherein a gradient of weight loss with respect to temperature in the main weight loss process in the thermogravimetric analysis of the recording layer material is 2% / ° C. or more.
<6> The light according to any one of <1> to <5>, wherein the total weight loss in the main weight loss process in the thermogravimetric analysis of the recording layer material is 30% or more and the weight loss start temperature is 350 ° C. or less. It is a recording medium.
<7> The refractive index n of the recording layer single layer with respect to light in the recording / reproducing wavelength ± 10 nm wavelength range is 1.5 ≦ n ≦ 3.0, and the extinction coefficient k is 0.02 ≦ k ≦ 0.2. The optical recording medium according to any one of <1> to <6>, wherein
<8> The optical recording medium according to <7>, wherein the recording / reproducing wavelength is 630 to 690 nm.
<9> The optical recording according to any one of <1> to <8>, wherein a track pitch in the substrate is 0.7 to 0.8 μm, and a guide groove width is 0.18 to 0.36 μm in half width. It is a medium.

  The optical recording medium of the present invention comprises a substrate and at least a recording layer on the substrate, and the recording layer contains an azo metal chelate compound represented by the structural formula (1). As a result, it is compatible with high-speed recording, has excellent thermal decomposition behavior, can be recorded and reproduced with a laser beam having a wavelength range of 630 to 690 nm, and has improved light resistance and storage stability. Type DVD media.

  According to the present invention, various problems in the prior art can be solved, and by using a novel azo metal chelate compound as a recording layer material, it is possible to cope with high-speed recording, excellent thermal decomposition behavior, and a laser having a wavelength range of 630 to 690 nm. It is possible to provide an optical recording medium that can be stably recorded and reproduced with light, and has excellent light resistance and storage stability.

(Optical recording medium)
The optical recording medium of the present invention comprises a substrate and at least a recording layer on the substrate, and has a reflective layer, a protective layer, and other layers as required.

  The recording layer contains an azo metal chelate compound represented by the following structural formula (1), and further contains other components as necessary.

ただし、前記構造式（１）中、Ｘは、カルコゲンから選択される原子を表す。環Ａは、隣接するＸ原子と窒素原子とが一緒になって形成される５員環を表し、該５員環は更に置換基で置換されていてもよい。Ｒ^１〜Ｒ^５は、互いに同一であってもよいし、異なっていてもよく、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、アルキル基、アリール基、アルケニル基、アルキルオキシ基、アリールオキシ基、アルキルアミノ基、アリールアミノ基、アルキルカルボニルアミノ基、アリールカルボニルアミノ基、カルバモイル基、アルキルカルバモイル基、アリールカルバモイル基、アルキルスルホニルアミノ基、及びアリールスルホニルアミノ基のいずれかを表し、これらは更に置換基で置換されていてもよく、Ｒ^１〜Ｒ^５の中で隣接するものどうしが互いに連結して環を形成していてもよい。Ｍは、金属原子を表す。ｎは、２〜３の整数を表す。

In Structural Formula (1), X represents an atom selected from chalcogen. Ring A represents a 5-membered ring formed by combining an adjacent X atom and a nitrogen atom, and the 5-membered ring may be further substituted with a substituent. R ^{1 to} R ⁵ may be the same as or different from each other, and are a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxy group, an amino group, an alkyl group, an aryl group, or an alkenyl group. , Alkyloxy group, aryloxy group, alkylamino group, arylamino group, alkylcarbonylamino group, arylcarbonylamino group, carbamoyl group, alkylcarbamoyl group, arylcarbamoyl group, alkylsulfonylamino group, and arylsulfonylamino group These may be further substituted with a substituent, and adjacent ones of R ^{1 to} R ⁵ may be linked to each other to form a ring. M represents a metal atom. n represents an integer of 2 to 3.

  In the structural formula (1), X represents an atom selected from chalcogen, and examples thereof include an oxygen atom, a sulfur atom, a selenium atom, a tellurium atom, and a polonium atom.

  The ring A represents a 5-membered ring formed by combining an adjacent X atom and a nitrogen atom. Examples of the 5-membered ring include oxazole, thiazole, oxadiazole, thiadiazole, oxatriazole, thia And triazole, and the like. These may be further substituted with a substituent, and these may have a condensed ring. Specifically, any one represented by the following structural formula is preferable.

ただし、前記構造式中、Ｒ^８〜Ｒ^１４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、アルキル基、アリール基、アルケニル基、アルキルオキシ基、アリールオキシ基、アルキルアミノ基、アリールアミノ基、アルキルカルボニルアミノ基、アリールカルボニルアミノ基、カルバモイル基、アルキルカルバモイル基、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、アルキルカルボニル基、アリールカルボニル基、アルキルスルホニル基、及びアリールスルホニル基のいずれかを表し、これらは更に置換基で置換されていてもよく、Ｒ^８とＲ^９、Ｒ^１０とＲ^１１とは互いに連結して環を形成していてもよい。ｑは０〜４の整数を表し、ｑが２以上の場合には、隣接するものどうしが互いに連結して環を形成していてもよい。

However, in said structural formula, R < ⁸ > -R < ¹⁴ > is respectively independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxy group, an amino group, an alkyl group, an aryl group, an alkenyl group, an alkyloxy group, Aryloxy group, alkylamino group, arylamino group, alkylcarbonylamino group, arylcarbonylamino group, carbamoyl group, alkylcarbamoyl group, arylcarbamoyl group, alkylsulfonylamino group, arylsulfonylamino group, alkylcarbonyl group, arylcarbonyl group , An alkylsulfonyl group, and an arylsulfonyl group, which may be further substituted with a substituent, and R ⁸ and R ⁹ , R ¹⁰ and R ¹¹ are connected to each other to form a ring. May be. q represents an integer of 0 to 4, and when q is 2 or more, adjacent ones may be connected to each other to form a ring.

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

  There is no restriction | limiting in particular as said alkyl group, According to the objective, it can select suitably, For example, a methyl group, an ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, Primary alkyl group such as n-heptyl group, n-octyl group, n-nonyl group, n-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-methylheptyl group, 2-ethylhexyl group, 3-ethylhexyl group, isopropyl group, sec- Til group, 1-ethylpropyl group, 1-methylbutyl group, 1,2-dimethylpropyl 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-propylhexyl group, 1-isobutyl- Secondary alkyl group such as methylbutyl group; tertiary alkyl group such as neopentyl group, tert-butyl group, tert-hexyl group, tert-amyl group, tert-octyl group; cyclohexyl group, 4-methylcyclohexyl group, 4- And cycloalkyl groups such as ethylcyclohexyl group, 4-tert-butylcyclohexyl group, 4- (2-ethylhexyl) cyclohexyl group, bornyl group, isobornyl group, adamantane group, etc., and these primary and secondary alkyl groups are Further, it may be further substituted with a substituent. The substituent may be 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, oxygen, sulfur, etc. And may be substituted with the alkyl group through an atom such as 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, ethoxy A propyl group, a piperidino group, a pyrrolidino group, a morpholino group, etc. are mentioned. Examples of the alkyl group substituted via sulfur include a methylthioethyl group, an ethylthioethyl group, an ethylthiopropyl group, and a phenylthioethyl group. Examples of the alkyl group substituted via nitrogen include a dimethylaminoethyl group, a diethylaminoethyl group, a diethylaminopropyl group, and the like. Examples of the heterocyclic residue include indolyl group, furyl group, thienyl group, pyridyl group, piperidyl group, quinolyl group, isoquinolyl group, piperidino group, morpholino group, pyrrolidino group, pyrrolyl group, and the like.

  The aryl group is not particularly limited and may be appropriately selected depending on the intended purpose. , Anthracenyl group, triphenylenyl group, pyrenyl group, and the like, and the aryl group may be further substituted with a substituent.

  The alkenyl group is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a 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, 2,2-dimethyl-1-butenyl group, 1,3-pentadienyl group, 1,4-pentadienyl group, 1-pentene-3-ynyl group, A 1-pentene-4-ynyl group, and the like, and the alkenyl group may be further substituted with a substituent.

The alkyloxy group may be any group in which a substituted or unsubstituted alkyl group is directly bonded to an oxygen atom. Examples of the alkyl group include the specific examples described above, and the alkyloxy group further includes a substituent. May be substituted.
The aryloxy group may be any group in which a substituted or unsubstituted aryl group is directly bonded to an oxygen atom. Examples of the aryl group include the specific examples described above, and the aryloxy group further includes a substituent. May be substituted.
The alkylamino group may be any group in which a directly substituted or unsubstituted alkyl group is bonded to the nitrogen atom of the amino group, and examples of the alkyl group include the specific examples described above. Further, it may be substituted with a substituent.
The arylamino group may be any group in which a directly substituted or unsubstituted aryl group is bonded to the nitrogen atom of the amino group. Examples of the aryl group include the specific examples described above. Further, it may be substituted with a substituent.
The alkylcarbonylamino group may be any group in which a substituted or unsubstituted alkyl group is bonded directly to a carbon atom of the carbonylamino group, and examples of the alkyl group include the specific examples described above. The amino group may be further substituted with a substituent.
The arylcarbonylamino group may be any group in which a directly or unsubstituted aryl group is bonded to a carbon atom of the carbonylamino group, and examples of the aryl group include the specific examples described above. The amino group may be further substituted with a substituent.
The alkylcarbamoyl group may be any group in which a hydrogen atom, a substituted or unsubstituted alkyl group is bonded directly and independently to the nitrogen atom of the carbamoyl group, and examples of the alkyl group include the specific examples described above. The alkylcarbamoyl group may be further substituted with a substituent.
The arylcarbamoyl group may be any group in which a hydrogen atom, a substituted or unsubstituted aryl group is directly and independently bonded to the nitrogen atom of the carbamoyl group. Examples of the aryl group include the specific examples described above. The arylcarbamoyl group may be further substituted with a substituent.
The alkylsulfonylamino group is not particularly limited as long as the sulfur atom of the sulfonylamino group is bonded directly or unsubstituted alkyl group, and examples of the alkyl group include the specific examples described above. The amino group may be further substituted with a substituent.
The arylsulfonylamino group may be any group as long as a directly substituted or unsubstituted aryl group is bonded to the sulfur atom of the sulfonylamino group. Examples of the aryl group include the specific examples described above. The amino group may be further substituted with a substituent.

ただし、前記構造式（２）中、Ｒ^６及びＲ^７は、互いに同一であってもよいし、異なっていてもよく、水素原子、アルキル基、及びアリール基のいずれかを表し、これらは更に置換基により置換されていてもよく、互いに連結して環を形成していてもよい。なお、置換基の具体例は、前述のものと同じである。 R ³ in the structural formula (1) is preferably represented by the following structural formula (2).

However, in the structural formula (2), R ⁶ and R ⁷ may be the same as or different from each other, and represent any one of a hydrogen atom, an alkyl group, and an aryl group. They may be substituted with a substituent, and may be linked to each other to form a ring. Specific examples of the substituent are the same as those described above.

  The aryl group, alkenyl group, alkyloxy group, aryloxy group, alkylamino group, arylamino group, alkylcarbonylamino group, arylcarbonylamino group, carbamoyl group, alkylcarbamoyl group, arylcarbamoyl group, alkylsulfonylamino group , An arylsulfonylamino group, an alkylcarbonyl group, an arylcarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, a heterocyclic ring, a hydrocarbon ring, and the like may have a substituent. Examples of the substituent include a hydroxyl group, a carboxyl group, a halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a nitro group, and a substituted or unsubstituted amino group. Examples of the alkyl moiety in the halogen atom, the alkyl group, and the alkoxy group include those described above.

  Examples of the metal atom include manganese, iron, cobalt, nickel, copper, and zinc. Among these, nickel and copper are particularly preferable in terms of excellent optical characteristics such as light resistance and refractive index. .

  As the azo metal chelate compound, for example, those represented by the following structural formulas (3) to (5) are suitable.

ただし、前記構造式（３）中、Ｒ^８及びＲ^９は、互いに同一であってもよいし、異なっていてもよく、水素原子、アルキル基、及びアリール基のいずれかを表し、これらは更に置換基により置換されていてもよく、互いに連結して環を形成していてもよい。Ｒ^１０〜Ｒ^１５は、互いに同一であってもよいし、異なっていてもよく、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、アルキル基、アリール基、アルケニル基、アルキルオキシ基、アリールオキシ基、アルキルアミノ基、アリールアミノ基、アルキルカルボニルアミノ基、アリールカルボニルアミノ基、カルバモイル基、アルキルカルバモイル基、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、アルキルカルボニル基、アリールカルボニル基、アルキルスルホニル基、及びアリールスルホニル基のいずれかを表し、これらは更に置換基で置換されていてもよく、Ｒ^８〜Ｒ^１５の中で隣接するものどうしが互いに連結して環を形成していてもよい。Ｍは、金属原子を表す。ｎは、２〜３の整数を表す。なお、置換基の具体例は、前述のものと同じである。

However, in the structural formula (3), R ⁸ and R ⁹ may be the same as or different from each other, and represent any one of a hydrogen atom, an alkyl group, and an aryl group. They may be substituted with a substituent, and may be linked to each other to form a ring. R ^{10 to} R ¹⁵ may be the same as or different from each other, and are a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxy group, an amino group, an alkyl group, an aryl group, or an alkenyl group. , Alkyloxy group, aryloxy group, alkylamino group, arylamino group, alkylcarbonylamino group, arylcarbonylamino group, carbamoyl group, alkylcarbamoyl group, arylcarbamoyl group, alkylsulfonylamino group, arylsulfonylamino group, alkylcarbonyl Group, an arylcarbonyl group, an alkylsulfonyl group, and an arylsulfonyl group, which may be further substituted with a substituent, and adjacent ones of R ^{8 to} R ¹⁵ are linked to each other. A ring may be formed. M represents a metal atom. n represents an integer of 2 to 3. Specific examples of the substituent are the same as those described above.

ただし、前記構造式（４）中、Ｒ^１６及びＲ^１７は、互いに同一であってもよいし、異なっていてもよく、水素原子、アルキル基、及びアリール基のいずれかを表し、これらは更に置換基により置換されていてもよく、互いに連結して環を形成していてもよい。Ｒ^１８〜Ｒ^２２は、互いに同一であってもよいし、異なっていてもよく、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、アルキル基、アリール基、アルケニル基、アルキルオキシ基、アリールオキシ基、アルキルアミノ基、アリールアミノ基、アルキルカルボニルアミノ基、アリールカルボニルアミノ基、カルバモイル基、アルキルカルバモイル基、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、アルキルカルボニル基、アリールカルボニル基、アルキルスルホニル基、及びアリールスルホニル基のいずれかを表し、これらは更に置換基で置換されていてもよく、Ｒ^１６〜Ｒ^２２の中で隣接するものどうしが互いに連結して環を形成していてもよい。Ｍは、金属原子を表す。ｎは、２〜３の整数を表す。なお、置換基の具体例は、前述のものと同じである。

However, in the structural formula (4), R ¹⁶ and R ¹⁷ may be the same as or different from each other, and represent any one of a hydrogen atom, an alkyl group, and an aryl group. They may be substituted with a substituent, and may be linked to each other to form a ring. R ^{18 to} R ²² may be the same as or different from each other, and are a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxy group, an amino group, an alkyl group, an aryl group, or an alkenyl group. , Alkyloxy group, aryloxy group, alkylamino group, arylamino group, alkylcarbonylamino group, arylcarbonylamino group, carbamoyl group, alkylcarbamoyl group, arylcarbamoyl group, alkylsulfonylamino group, arylsulfonylamino group, alkylcarbonyl Group, an arylcarbonyl group, an alkylsulfonyl group, and an arylsulfonyl group, which may be further substituted with a substituent, and adjacent ones of R ^{16 to} R ²² are connected to each other. A ring may be formed. M represents a metal atom. n represents an integer of 2 to 3. Specific examples of the substituent are the same as those described above.

ただし、前記構造式（５）中、Ｒ^２３及びＲ^２４は、互いに同一であってもよいし、異なっていてもよく、水素原子、アルキル基、及びアリール基のいずれかを表し、これらは更に置換基により置換されていてもよく、互いに連結して環を形成していてもよい。Ｒ^２５〜Ｒ^３０は、互いに同一であってもよいし、異なっていてもよく、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、アルキル基、アリール基、アルケニル基、アルキルオキシ基、アリールオキシ基、アルキルアミノ基、アリールアミノ基、アルキルカルボニルアミノ基、アリールカルボニルアミノ基、カルバモイル基、アルキルカルバモイル基、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、アルキルカルボニル基、アリールカルボニル基、アルキルスルホニル基、及びアリールスルホニル基のいずれかを表し、これらは更に置換基で置換されていてもよく、Ｒ^２３〜Ｒ^３０の中で隣接するものどうしが互いに連結して環を形成していてもよい。Ｍは、金属原子を表す。ｎは、２〜３の整数を表す。なお、置換基の具体例は、前述のものと同じである。

However, in the structural formula (5), R ²³ and R ²⁴ may be the same as or different from each other, and represent any one of a hydrogen atom, an alkyl group, and an aryl group. They may be substituted with a substituent, and may be linked to each other to form a ring. R ^{25 to} R ³⁰ may be the same as or different from each other, and are a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxy group, an amino group, an alkyl group, an aryl group, or an alkenyl group. , Alkyloxy group, aryloxy group, alkylamino group, arylamino group, alkylcarbonylamino group, arylcarbonylamino group, carbamoyl group, alkylcarbamoyl group, arylcarbamoyl group, alkylsulfonylamino group, arylsulfonylamino group, alkylcarbonyl Group, an arylcarbonyl group, an alkylsulfonyl group, and an arylsulfonyl group, which may be further substituted with a substituent, and adjacent ones of R ^{23 to} R ³⁰ are connected to each other. A ring may be formed. M represents a metal atom. n represents an integer of 2 to 3. Specific examples of the substituent are the same as those described above.

  The azo metal chelate compound is obtained, for example, by reacting an azo-substituted indole compound represented by the following structural formula (1-1) with a metal salt.

ただし、前記構造式（１−１）中、Ｘ、環Ａ、Ｒ^１〜Ｒ^５は、上記と同じ意味を表す。

However, the structural formula (1-1), X, Ring ^A, R 1 to R ⁵ are the same as defined above.

The method for producing the azo-substituted indole compound is not particularly limited and may be appropriately selected from known methods according to the purpose. For example, an indole having an electron donating group at the 4-position and a 2-position Heterocyclic 5-membered rings having an unsubstituted amino group can be easily synthesized by a conventional azo coupling. Specifically, the 2-position of an acid such as hydrochloric acid, sulfuric acid, acetic acid, phosphoric acid, etc. A 5-membered heterocyclic ring having an amino group is dissolved by heating and rapidly cooled in an ice bath. Thereafter, nitrous acid is allowed to act at an appropriate temperature for diazotization. Next, the target azo-substituted indole compound can be synthesized by coupling with an indole having an electron donating group at the 4-position.
Among the electron donating groups, an amino group, a substituted or unsubstituted alkylamino group, and a substituted or unsubstituted arylamino group are particularly preferable because the desired product can be obtained with few by-products under mild reaction conditions.

As the heterocyclic 5-membered ring constituting the azo-substituted indole compound, thiazole, thiadiazole, and oxazole are particularly preferable in that good decomposition behavior is obtained and the raw materials are easily available.
The azo-substituted indole compound can easily generate an azo metal chelate compound represented by the structural formula (1) by acting with a metal salt or the like.
For the synthesis of the azo metal chelate compound, an azo-substituted indole compound represented by the structural formula (1-1) and a metal salt are added to a solvent such as methanol, dimethylformamide (DMF), or glycerin. In some cases, an alkali component such as 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.

Next, items necessary for configuring a recording layer in an optical recording medium include optical characteristics and thermal characteristics.
It is preferable that the optical characteristics have a large absorption band on the short wavelength side with respect to the recording / reproducing wavelength of 630 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 to 690 nm.
Specifically, the refractive index n of the recording layer single layer with respect to light in the wavelength range near the long wavelength near the recording / reproducing wavelength is 1.5 to 3.0, and the extinction coefficient k is 0.02 to 0.2. A range is preferred. If the refractive index n is less than 1.5, it is difficult to obtain a sufficient optical change, so that the recording modulation degree may be lowered, and if it exceeds 3.0, the wavelength dependency becomes too high. An error may occur even in the reproduction wavelength region. If the extinction coefficient k is less than 0.02, the recording sensitivity may be deteriorated, and if it exceeds 0.2, it may be difficult to obtain a reflectance of 50% or more.

As the thermally necessary condition, it is preferable that the weight loss in the main weight loss process in the thermogravimetric analysis (TG) is abrupt with respect to the temperature. This is because the recording layer material 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. Accordingly, 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 recording layer 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 with the largest weight loss rate is called the main weight loss process. The slope of the weight loss can be determined as follows.

As shown in FIG. 1, the recording layer material having a weight of m0 is heated at 10 ° C./min in a nitrogen atmosphere. As the temperature rises, the weight of the recording layer material decreases by a small amount and shows a weight loss line (substantially a straight line ab). When a certain temperature is reached, the recording layer material undergoes a rapid weight loss, causing a weight loss substantially 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.
In FIG. 1, the temperature at the intersection of the straight line ab and the straight line cd is T1 (° C.), the remaining weight loss rate with respect to the initial weight m0 is m1 (%), and the intersection of the straight line cd and the straight line ef The temperature at is T2 (° C.), and the residual weight loss rate with respect to the initial mass m0 is m2 (%). The rapid weight loss start temperature is T1, the rapid weight loss end temperature is T2, and the slope of weight loss when a rapid weight loss is manifested is the following equation: (m1-m2) (%) / (T2-T1) ( ° C.), and the weight loss rate relative to the initial weight is indicated by (m1-m2) (%).
Here, “TG%” in FIG. 1 represents the weight loss rate of the recording layer material to be measured. The mass m0 of the recording layer material before the temperature rise is expressed as 100%, and the state where no substance is present in the measuring instrument is 0%.
Based on the above definition, the recording material used for the optical recording medium preferably has a weight loss gradient of 2% / ° C. or more in the main weight loss process. If the slope of the weight loss is less than 2% / ° C., the spread of the recording portion becomes large and it may be difficult to form a short recording portion.
The weight reduction rate in the main weight loss process is preferably 30% or more. If the weight reduction rate 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 loss starting temperature T1 is in a certain temperature range. Specifically, the weight loss starting temperature is preferably 350 ° C. or lower, and more preferably 200 to 350 ° C. If the weight loss starting temperature exceeds 350 ° C., the power of the recording laser beam becomes high and may not be practical, and if it is less than 200 ° C., the recording stability may be deteriorated such as reproduction deterioration.

  The optical recording medium of the present invention preferably has a recording / reproducing wavelength of 630 to 690 nm, can be rewritten at high speed, has excellent recording characteristics, and is particularly suitable for any of large capacity DVD + R and DVD-R. Used.

Next, the configuration of the optical recording medium of the present invention will be described with reference to the drawings.
FIG. 2 is a schematic cross-sectional view showing a layer configuration example applicable to the optical recording medium of the present invention, which is an example of a write-once optical disc. FIG. 2A shows a write-once optical disc composed of substrate 1 / recording layer 2. FIG. 2B shows a write-once optical disc composed of substrate 1 / undercoat layer 3 / recording layer 2. FIG. 2C shows a write-once optical disc composed of a substrate 1 / undercoat layer 3 / recording layer 2 / protective layer 4. FIG. 2D shows a write-once optical disc comprising a hard coat layer 5 / substrate 1 / undercoat layer 3 / recording layer 2 / protective layer 4.

FIG. 3 is a schematic cross-sectional view showing an example of the layer structure of a write-once optical recording medium (CD-R type) that can be applied to the optical recording medium of the present invention. This is an example of a write-once optical disk. FIG. 3A shows a CD-R composed of substrate 1 / recording layer 2 / reflection layer 6 / protective layer 4. FIG. FIG. 3B shows a CD-R composed of substrate 1 / undercoat layer 3 / recording layer 2 / reflection layer 6 / protective layer 4. FIG. 3C shows a CD-R composed of hard coat layer 5 / substrate 1 / undercoat layer 3 / recording layer 2 / reflective layer 6 / protective layer 4.
In addition, it is good also as what is called an air sandwich which stuck two sheets of FIG. 2 or FIG.

  FIG. 4 is a schematic cross-sectional view showing a layer configuration example of a write-once type optical recording medium (DVD + R or DVD-R) that can be applied to the optical recording medium of the present invention. FIG. 4A shows a DVD + R or DVD-R composed of substrate 1 / recording layer 2 / reflective layer 6 / protective layer 4. FIG. FIG. 4B shows a DVD + R or DVD-R composed of substrate 1 / recording layer 2 / reflection layer 6 / protective layer 4 / adhesive layer 8 / protective substrate 7. FIG. FIG. 4C shows a DVD + R or DVD-R composed of a hard coat layer 5 / substrate 1 / undercoat layer 3 / recording layer 2 / reflection layer 6 / protective layer 4 / adhesive layer 8 / protective substrate 7.

  As the configuration of the optical recording medium when the optical recording medium of the present invention is applied as a write-once DVD medium, a first substrate and a second substrate (hereinafter sometimes referred to as a first substrate and a second substrate) The basic structure is a structure in which is bonded with an adhesive via a recording layer. The recording layer needs to be a laminate of a recording layer and a reflective layer in order to increase the reflectance. 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 structure most commonly used is the structure of the first substrate / recording layer (organic dye layer) / reflective layer / protective layer / adhesive layer / second substrate.

-Board-
As the substrate, when performing at least one of recording and reproduction from the substrate side, it must be transparent to the laser beam used, and when performing at least one of recording and reproduction from the recording layer side, The substrate need not be transparent. Therefore, in the present invention, when two substrates are used in a sandwich shape, for example, if only one substrate (second substrate) is transparent, it does not matter whether the other substrate (first substrate) is transparent or opaque. Absent.

There is no restriction | limiting in particular as said board | substrate material, According to the objective, it can select suitably, For example, plastics, such as a polyester resin, an acrylic resin, a polyamide resin, a polycarbonate resin, a polyolefin resin, a phenol resin, an epoxy resin, a polyimide resin Glass, ceramics, metal, and the like can be used.
If only one layer is used, the pre-format such as tracking guide grooves and guide pits, and address signals, etc. on the surface of the substrate when two substrates are used in a sandwich shape. Is preferably formed.

The substrate is disk-shaped and usually has guide grooves with a depth of 1000 to 2500 mm (100 to 250 nm). Further, the groove width is preferably 0.18 to 0.36 μm in half width. The half width is preferably 0.18 μm or more because sufficient tracking error signal intensity can be easily obtained. On the other hand, it is preferable that the thickness is 0.36 μm or less because the recording portion hardly spreads laterally when recording.
The track pitch is usually preferably from 0.7 to 1.0 μm, and preferably from 0.7 to 0.8 μm for high capacity use.

-Recording layer-
The recording layer causes some optical change by irradiation with laser light, and can record information by the change, and it is necessary that the recording layer contains the dye of the present invention. In forming the recording layer, at least one selected from the dyes of the present invention (azo metal chelate compounds represented by the structural formula (1)) can be used in combination. The recording layer may be mixed or laminated with other organic dyes, metals, or metal compounds for the purpose of improving optical characteristics, recording sensitivity, signal characteristics, and the like.
Examples of the other organic dyes include polymethine dyes, naphthalocyanine dyes, phthalocyanine dyes, squarylium dyes, croconium dyes, pyrylium dyes, naphthoquinone dyes, anthraquinone (indanthrene) dyes, xanthene dyes. , Triphenylmethane dyes, azulene dyes, tetrehydrocholine dyes, phenanthrene dyes, triphenothiazine dyes, metal chelate compounds, etc., and one of these may be used alone or two of them The above may be combined.
Moreover, a metal or a metal compound can be added to the dye. As the metal or metal compound, for example, In, Te, Bi, Se, Sb, Ge, Sn, Al, Be, TeO ₂ , SnO, As, Cd and the like can be dispersedly mixed or used in a laminated form. .

  In addition, a polymer material can be blended in the dye. As the polymer material, for example, various materials such as ionomer resin, polyamide resin, vinyl resin, natural polymer compound, silicone, liquid rubber, or silane coupling agent may be dispersed and mixed. Alternatively, stabilizers (for example, transition metal complexes), dispersants, flame retardants, lubricants, antistatic agents, surfactants, plasticizers, and the like can be used together for the purpose of improving characteristics.

  The recording layer can be formed by ordinary means such as vapor deposition, sputtering, CVD, or solution coating. When the coating method is used, it can be performed by a conventional coating method such as a spray method, a roller coating method, a dipping method, or a spin coating by dissolving the dye or the like in an organic solvent or the like.

The organic solvent is not particularly limited and may be appropriately selected depending on the intended purpose. For example, alcohols such as methanol, ethanol, isopropanol, 2,2,3,3-tetrafluoropropanol; acetone, methyl ethyl ketone, Ketones such as cyclohexanone; amides such as N, N-dimethylformamide and N, N-dimethylacetamide; sulfoxides such as dimethyl sulfoxide; ethers such as tetrahydrofuran, dioxane, diethyl ether and ethylene glycol monomethyl ether; methyl acetate; Esters such as ethyl acetate; Aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethane, carbon tetrachloride, and trichloroethane; Aromatics such as benzene, xylene, monochlorobenzene, and dichlorobenzene ; Methoxyethanol, cellosolves such as ethoxyethanol; hexane, pentane, cyclohexane, hydrocarbons such as methylcyclohexane, and the like.
The film thickness of the recording layer is not particularly limited and may be appropriately selected depending on the intended purpose, and is usually preferably 100 mm (10 nm) to 10 μm.

-Undercoat layer-
The undercoat layer comprises (1) improved adhesion, (2) a barrier such as water or gas, (3) improved storage stability of the recording layer, (4) improved reflectance, and (5) from a solvent. It is used for the purpose of protecting the substrate and recording layer, and (6) formation of guide grooves, guide pits, preformats, and the like.
For the purpose of (1), polymer materials such as ionomer resins, polyamide resins, vinyl resins, natural resins, natural polymers, silicones, various rubber substances such as liquid rubber, silane coupling agents, etc. Can be used. For the purposes of (2) and (3), in addition to the polymer material, an inorganic compound such as SiO ₂ , MgF ₂ , SiO, TiO ₂ , ZnO, TiN, SiN, etc., and also a metal or semi-metal such as Zn, Cu, Ni, Cr, Ge, Se, Au, Ag, Al, or the like can be used. For the purpose of (4), 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 (5) and (6), an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used.

  There is no restriction | limiting in particular in the film thickness of the said undercoat layer, According to the objective, it can select suitably, 0.01-30 micrometers is preferable and 0.05-10 micrometers is more preferable.

-Reflective layer-
Examples of the material of the reflective layer include metals, semi-metals, and the like that can be obtained with a high reflectivity by themselves, such as Au, Ag, Cr, Ni, Al, Fe, and Sn. Au, Ag, and Al are the most preferable from the viewpoint of rate and productivity, and these metals and metalloids may be used alone or as two kinds of alloys.

The reflective layer can be formed by various vapor deposition methods such as vacuum deposition, sputtering, plasma CVD, photo CVD, ion plating, and electron beam deposition. Among these, the sputtering method is excellent in mass productivity and film quality.
There is no restriction | limiting in particular in the film thickness of the said reflection layer, According to the objective, it can select suitably, 50-5000 mm (5-500 nm) is preferable and 100-3000 mm (10-300 nm) is more preferable.

-Protective layer and substrate surface hard coat layer-
The protective layer or the substrate surface hard coat layer is (1) protection from scratches, dust, dirt, etc. of the recording layer (reflection / absorption layer), (2) improvement in storage stability of the recording layer (reflection / absorption layer), (3) Used for the purpose of improving the reflectance. For these purposes, the materials shown in the intermediate layer can be used. Examples of the inorganic materials, for example, can be used SiO, _also, SiO _2. Examples of organic materials include polymethyl acrylate resin, polycarbonate resin, epoxy resin, polystyrene resin, polyester resin, vinyl resin, cellulose, aliphatic hydrocarbon resin, aromatic hydrocarbon resin, natural rubber, styrene butadiene resin, and chloroprene rubber. Also, heat softening resins such as wax, alkyd resin, drying oil, rosin, heat melting resin, and ultraviolet curable resin can be used. Among these materials, the most preferable example of the protective layer or the substrate surface hard coat layer is an ultraviolet curable resin excellent in productivity.
There is no restriction | limiting in particular in the film thickness of the said protective layer or a substrate surface hard-coat layer, According to the objective, it can select suitably, 0.01-30 micrometers is preferable and 0.05-10 micrometers is more preferable.

  In the present invention, as in the case of the recording layer, the undercoat layer, the protective layer, and the substrate surface hard coat layer may further include a stabilizer, a dispersant, a flame retardant, a lubricant, and an antistatic agent, depending on the purpose. An agent, a surfactant, a plasticizer, and the like can be contained.

−Protection board−
When the protective substrate is irradiated with laser light from the protective substrate side, it must be transparent to the laser beam used, and when used as a simple protective plate, transparency is not an issue. The substrate material that can be used as the protective substrate is exactly the same as the substrate material, for example, plastics such as polyester resin, acrylic resin, polyamide resin, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, polyimide resin, Glass, ceramics, metal, etc. can be used.

-Adhesive, adhesive layer-
The adhesive is not particularly limited as long as it is a material capable of bonding two optical recording media, and can be appropriately selected according to the purpose. In view of productivity, an ultraviolet curable adhesive or a hot-melt adhesive is used. An adhesive is preferred.

The optical recording medium recording / reproducing method of the present invention performs at least one of recording and reproducing information by irradiating the optical recording medium of the present invention with a laser beam having an oscillation wavelength of 630 to 690 nm. is there.
Specifically, while rotating the optical recording medium at a predetermined linear velocity or a predetermined constant angular velocity, a semiconductor laser (for example, an oscillation wavelength of 630 to 690 nm) or the like from the surface protective layer side through the objective lens. Irradiate recording light. By this irradiation light, the recording layer absorbs the light and the temperature rises locally. For example, information is recorded by generating pits and changing their optical characteristics. The information recorded as described above can be reproduced by irradiating a laser beam from the surface protective layer side while rotating the optical recording medium at a predetermined constant linear velocity and detecting the reflected light.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Example 1)
-Production of optical recording media-
A polycarbonate resin substrate having a thickness of 0.6 mm was produced by injection molding, and a guide groove having a depth of 1650 mm (165 nm), a half width of 0.25 μm, and a track pitch of 0.74 μm was formed on the substrate using a photopolymer. .
A 2,2,3,3-tetrafluoropropanol solution of Compound 1 represented by the following structural formula is applied onto a substrate by spinner coating and dried at 100 ° C. for 30 minutes to form a recording layer having a thickness of 800 mm (80 nm). did. A silver (Ag) film was formed on the recording layer by a sputtering method so as to have a thickness of 1000 mm (100 nm) to form a reflective layer. Next, an acrylic photopolymer was applied on the reflective layer to a thickness of 7 μm to form a protective layer. Next, a polycarbonate resin substrate having a thickness of 0.6 mm was bonded using an acrylic photopolymer. Thus, an optical recording medium was produced.

(Example 2)
-Production of optical recording media-
In Example 1, an optical recording medium was produced in the same manner as Example 1 except that Compound 2 represented by the following structural formula was used instead of Compound 1.

(Example 3)
-Production of optical recording media-
In Example 1, an optical recording medium was produced in the same manner as in Example 1 except that Compound 3 represented by the following structural formula was used instead of Compound 1.

Example 4
-Production of optical recording media-
In Example 1, an optical recording medium was produced in the same manner as Example 1 except that Compound 4 represented by the following structural formula was used instead of Compound 1.

(Example 5)
-Production of optical recording media-
In Example 1, an optical recording medium was produced in the same manner as Example 1 except that Compound 5 represented by the following structural formula was used instead of Compound 1.

(Example 6)
-Production of optical recording media-
In Example 1, an optical recording medium was produced in the same manner as Example 1 except that Compound 6 represented by the following structural formula was used instead of Compound 1.

(Example 7)
-Production of optical recording media-
In Example 1, an optical recording medium was produced in the same manner as in Example 1 except that the compound 7 represented by the following structural formula was used instead of the compound 1.

(Example 8)
-Production of optical recording media-
In Example 1, an optical recording medium was produced in the same manner as in Example 1, except that Compound 8 represented by the following structural formula was used instead of Compound 1.

Example 9
-Production of optical recording media-
In Example 1, an optical recording medium was produced in the same manner as Example 1 except that Compound 9 represented by the following structural formula was used instead of Compound 1.

(Example 10)
-Production of optical recording media-
In Example 1, an optical recording medium was produced in the same manner as Example 1 except that the compound 10 represented by the following structural formula was used instead of the compound 1.

(Example 11)
-Production of optical recording media-
In Example 1, an optical recording medium was produced in the same manner as in Example 1 except that the compound 11 represented by the following structural formula was used instead of the compound 1.

(Example 12)
-Production of optical recording media-
In Example 1, an optical recording medium was produced in the same manner as Example 1 except that Compound 12 represented by the following structural formula was used instead of Compound 1.

(Example 13)
-Production of optical recording media-
In Example 1, an optical recording medium was produced in the same manner as Example 1 except that Compound 13 represented by the following structural formula was used instead of Compound 1.

(Example 14)
-Production of optical recording media-
In Example 1, an optical recording medium was produced in the same manner as Example 1 except that Compound 14 represented by the following structural formula was used instead of Compound 1.

(Example 15)
-Production of optical recording media-
In Example 1, an optical recording medium was produced in the same manner as Example 1 except that Compound 15 represented by the following structural formula was used instead of Compound 1.

(Example 16)
-Production of optical recording media-
In Example 1, an optical recording medium was produced in the same manner as Example 1 except that Compound 16 represented by the following structural formula was used instead of Compound 1.

(Example 17)
-Production of optical recording media-
In Example 1, an optical recording medium was produced in the same manner as in Example 1 except that Compound 17 represented by the following structural formula was used instead of Compound 1.

(Example 18)
-Production of optical recording media-
In Example 1, an optical recording medium was produced in the same manner as in Example 1 except that Compound 18 represented by the following structural formula was used instead of Compound 1.

(Example 19)
-Production of optical recording media-
In Example 1, an optical recording medium was produced in the same manner as Example 1 except that Compound 19 represented by the following structural formula was used instead of Compound 1.

  Next, for each of the obtained optical recording media of Examples 1 to 19, a recording test light resistance test and a storage test were performed as follows. The results are shown in Table 1.

<Recording test>
Using an optical disk evaluation apparatus (DDU-1000 manufactured by Pulse Tech Co., Ltd.) for each of the produced optical recording media, a semiconductor laser beam having a laser oscillation wavelength of 658 nm and a beam diameter of 1.0 μm is used for tracking and an EFM signal (linear velocity) 14 m / sec.) Was recorded and reproduced with continuous light (reproduction power 0.7 mW) of a semiconductor laser having an oscillation wavelength of 670 nm, the reproduction waveform was observed, and the reflectivity, modulation degree, and jitter were measured.
<Light resistance test>
Each optical recording medium was irradiated with 50,000 Lux xenon (Xe) light continuously for 20 hours, and the reflectance, modulation factor, and jitter were measured in the same manner as described above.
<Storage test>
Each optical recording medium was stored for 600 hours in an environment of 60 ° C. and 90% relative humidity, and the reflectance, modulation factor, and jitter were measured in the same manner as described above.

表１の結果から、実施例５〜１０は、金属原子が異なる以外は共通するアゾ金属キレート化合物（化合物５〜１０）を用いており、これらの評価結果から、いずれも初期特性は良好であり、特に金属原子がニッケル、銅、及び亜鉛である実施例８〜１０（化合物８〜１０）が優れていることが認められる。
また、金属原子がニッケル及び銅である実施例８及び９（化合物８及び９）は、実施例５〜７及び１０に比べて優れた耐光性及び保存安定性を有することが認められる。
これらの結果から見て、総合的に優れた特性を有するのは、金属原子がニッケル及び銅のアゾ金属キレート化合物を用いたものである。なお、実施例１０（化合物１０）は、金属原子がＺｎであるため、初期特性は優れているが、耐光性及び保存安定性には劣るものである。この場合、実施例１０は、包装材料及び包装方法を工夫することにより問題なく使用できる可能性がある。

From the results of Table 1, Examples 5 to 10 use common azo metal chelate compounds (Compounds 5 to 10) except that the metal atoms are different. From these evaluation results, all of the initial characteristics are good. In particular, it can be seen that Examples 8 to 10 (Compounds 8 to 10) in which the metal atoms are nickel, copper, and zinc are excellent.
Moreover, it is recognized that Examples 8 and 9 (compounds 8 and 9) in which the metal atoms are nickel and copper have superior light resistance and storage stability as compared with Examples 5 to 7 and 10.
From these results, it is the use of azo metal chelate compounds in which the metal atoms are nickel and copper that have comprehensively excellent characteristics. In addition, Example 10 (Compound 10) has excellent initial characteristics because the metal atom is Zn, but is inferior in light resistance and storage stability. In this case, Example 10 may be used without any problem by devising the packaging material and the packaging method.

  The optical recording medium of the present invention has excellent recording characteristics, can be rewritten at high speed, and can be widely used for large capacity write-once DVD disk systems such as DVD + R and DVD-R.

FIG. 1 is a diagram for explaining a main weight loss process of an azo metal chelate compound and a method for obtaining a weight loss rate. 2A to 2D are diagrams illustrating an example of a layer structure of a normal write-once type optical recording medium. 3A to 3C are diagrams illustrating an example of a layer configuration of an optical recording medium for CD-R. 4A to 4C are diagrams illustrating an example of a layer configuration of an optical recording medium for DVD + R or DVD-R.

Explanation of symbols

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

Claims (9)

An optical recording medium comprising a substrate and at least a recording layer on the substrate, wherein the recording layer contains an azo metal chelate compound represented by the following structural formula (1).

In Structural Formula (1), X represents an atom selected from chalcogen. Ring A represents a 5-membered ring formed by combining an adjacent X atom and a nitrogen atom, and the 5-membered ring may be further substituted with a substituent. R ^{1 to} R ⁵ may be the same as or different from each other, and are a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxy group, an amino group, an alkyl group, an aryl group, or an alkenyl group. , Alkyloxy group, aryloxy group, alkylamino group, arylamino group, alkylcarbonylamino group, arylcarbonylamino group, carbamoyl group, alkylcarbamoyl group, arylcarbamoyl group, alkylsulfonylamino group, and arylsulfonylamino group These may be further substituted with a substituent, and adjacent ones of R ^{1 to} R ⁵ may be linked to each other to form a ring. M represents a metal atom. n represents an integer of 2 to 3. The optical recording medium according to claim 1, wherein R ³ is represented by the following structural formula (2).

However, in the structural formula (2), R ⁶ and R ⁷ may be the same as or different from each other, and represent any one of a hydrogen atom, an alkyl group, and an aryl group. They may be substituted with a substituent, and may be linked to each other to form a ring. The optical recording medium according to claim 1, wherein the ring A is any one of the following structural formulas.

However, in said structural formula, R < ⁸ > -R < ¹⁴ > is respectively independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxy group, an amino group, an alkyl group, an aryl group, an alkenyl group, an alkyloxy group, Aryloxy group, alkylamino group, arylamino group, alkylcarbonylamino group, arylcarbonylamino group, carbamoyl group, alkylcarbamoyl group, arylcarbamoyl group, alkylsulfonylamino group, arylsulfonylamino group, alkylcarbonyl group, arylcarbonyl group , An alkylsulfonyl group, and an arylsulfonyl group, which may be further substituted with a substituent, and R ⁸ and R ⁹ , R ¹⁰ and R ¹¹ are connected to each other to form a ring. May be. q represents an integer of 0 to 4, and when q is 2 or more, adjacent ones may be connected to each other to form a ring.   The optical recording medium according to claim 1, wherein the metal atom is any one of nickel and copper.   The optical recording medium according to any one of claims 1 to 4, wherein a slope of weight loss with respect to temperature in the main weight loss process in the thermogravimetric analysis of the recording layer material is 2% / ° C or more.   6. The optical recording medium according to claim 1, wherein the total weight loss in the main weight loss process in the thermogravimetric analysis of the recording layer material is 30% or more, and the weight loss start temperature is 350 ° C. or less.   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. Item 7. The optical recording medium according to any one of Items 1 to 6.   The optical recording medium according to claim 7, wherein the recording / reproducing wavelength is 630 to 690 nm. 9. 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 guide groove width is 0.18 to 0.36 [mu] m in half width.

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