JP2006116720A - Optical information recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical information recording medium which has high reflectance and degree of modulation even at a high recording rate more than 4 times as much and can acquire a low enough jitter in a broad range of recording rates 1 to 16 times as much. <P>SOLUTION: This optical information recording medium contains coloring matter of the structure represented by formula (1), wherein Ma<SP>21</SP>to Ma<SP>26</SP>are each a methine group; Ka<SP>21</SP>and Ka<SP>22</SP>are each an integer of 0 to 3; Q is a cation which neutralizes an electric charge; EWD is an electron-attracting group; EWD<SB>1</SB>and EWD<SB>2</SB>, EWD<SB>11</SB>and EWD<SB>21</SB>, EWD<SB>3</SB>and EWD<SB>4</SB>and EWD<SB>31</SB>and EWD<SB>41</SB>can each assume an annular structure by connecting each other; L<SP>11</SP>is a linkage group; and "n" is 0 to 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat mode type information recording medium and an information recording method capable of writing (recording) and reading (reproducing) information using a laser beam having a high energy density. In particular, the present invention relates to a heat mode type information recording medium such as a write-once digital versatile disk (DVD-R) suitable for recording information using visible laser light.

Conventionally, an information recording medium (optical disk) capable of recording information only once by a laser beam is known. The information recording medium is also referred to as a write-once type CD (so-called CD-R), and has an advantage that it can provide a small amount of CD at a reasonable price and quickly compared with the production of a conventional CD. The demand for computers is increasing with the spread of computers. A typical structure of a CD-R type information recording medium is such that a recording layer made of an organic dye, a reflective layer made of a metal such as gold, and a protective layer made of resin are laminated in this order on a transparent disk-shaped substrate. It is.
Information is recorded on the optical disk by irradiating a near-infrared laser beam (usually a laser beam having a wavelength of around 780 nm) to locally generate heat and deform the recording layer. On the other hand, reading (reproduction) of information is usually performed by irradiating a laser beam having the same wavelength as the recording laser beam, and reflecting the portion of the recording layer where heat is deformed (recorded portion) and the portion where the recording layer is not deformed (unrecorded portion). This is done by detecting the difference in rate.

  In recent years, information recording media with higher recording density have been demanded. In order to increase the recording density, it is effective to reduce the diameter of the irradiated laser beam, and it is theoretically known that laser light with a shorter wavelength can be reduced to a smaller value, which is advantageous for higher density. It has been. Therefore, development of an optical disc for recording and reproduction using a laser beam having a wavelength shorter than 780 nm, which has been conventionally used, has been promoted. Optical discs have been proposed. This optical disc has a recording layer made of a dye on a transparent disk-shaped substrate having a diameter of 120 mm or 80 mm in diameter, on which a pregroove having a track pitch of 0.8 μm narrower than the CD-R of 1.6 μm is formed, and usually A structure in which two discs each further provided with a reflective layer and a protective layer are provided on the recording layer, or a disc-like protective substrate having substantially the same dimensions as the disc is bonded with an adhesive with the recording layer inside. It is manufactured to be. The DVD-R is recorded and reproduced by irradiating with visible laser light (usually laser light having a wavelength in the range of 600 nm to 700 nm), and can be recorded at higher density than the CD-R type optical disc. It is said. Also, DVD + R optical discs similar to DVD-R are on the market.

  Since the DVD-R type information recording medium can record several times the amount of information as compared with the conventional CD-R type, the DVD-R type information recording medium has not only high recording sensitivity but also a large amount of information. Therefore, it is desirable that the error rate be small even for high-speed recording. In addition, since a recording layer made of a dye generally has low stability over time to heat or light, it is desired to develop a recording layer that can maintain stable performance against heat or light over a long period of time.

Japanese Unexamined Patent Publication No. 10-226170 [Patent Document 1] discloses a DVD-R type information recording medium in which a recording layer made of a cyanine dye is provided on a substrate. It is said that an information recording medium having high recording sensitivity and high reflectance can be obtained by using this dye compound. Japanese Patent Application Laid-Open No. 2001-287456 [Patent Document 2] discloses an information recording medium in which a recording layer made of a cyanine dye compound is provided on a substrate. By using this dye compound, an excellent recording medium is disclosed. It has recording characteristics, and the recording characteristics can be stably maintained over a long period of time. On the other hand, Japanese Patent Laid-Open No. 63-209995 [Patent Document 3] discloses a CD-R type information recording medium in which a recording layer made of an oxonol dye is provided on a substrate. By using this dye compound, it is said that stable recording / reproducing characteristics can be maintained over a long period of time. Here, an oxonol dye compound in which ammonium is introduced in the form of a salt in the molecule is described. JP-A-2000-52658 [Patent Document 4] and JP-A-2004-188968 [Patent Document 5] provide an optical information recording medium exhibiting high light resistance and durability and having good recording characteristics. Oxonol dye compounds are described.
JP-A-10-226170 JP 2001-287456 A Japanese Patent Laid-Open No. 63-209995 JP 2000-52658 A JP 2004-188968 A

The inventor of the present invention used various cyanine dye compounds and oxonol dye compounds described in the above publication for DVD-R type optical information recording media, and examined their performance. As a result, the DVD-R type optical information recording medium containing the dye compound in the recording layer exhibits extremely excellent recording characteristics at low speed recording at about 1 × speed and 2 × speed, while at the time of high speed recording at 4 × speed or higher. Although it showed comparatively excellent recording characteristics, it became clear that it did not have practically sufficient performance in terms of modulation degree and reflectance. In order to obtain an optical information recording medium that maintains good recording characteristics in low-speed recording of about 1 to 2 times speed and at the same time has good recording performance in high-speed recording of 4 times speed or more, in particular, sufficient reflectance and modulation. In the optical characteristics of the dye used, a dye having a complex refractive index (n + ik) having a real part n larger than that of the low speed recording dye and an imaginary part k having a value similar to or smaller than that of the low speed recording dye. It ’s fine. However, it has been very difficult to obtain a dye having a large real part n of the complex refractive index and a imaginary part k having the same or small value while maintaining good recording characteristics during low-speed recording.
Known dyes have low fastness to light, humidity and heat, and optical recording media using the dyes have low storage stability after recording.
An object of the present invention is to realize a real part of a complex refractive index that realizes a high reflectance and a high degree of modulation even in a high-speed recording of 4 × or higher speed while maintaining good recording characteristics in a low-speed recording of about 1-2 × speed. It is to provide a pigment having a large n and an imaginary part k that is the same or small. Another object of the present invention is to provide a dye that achieves sufficiently low jitter at a wide recording speed such as 1-16 times speed recording. Another object of the present invention is to provide an optical recording medium that uses a dye having high fastness to humidity and heat and has excellent storage stability after recording.

  As a result of intensive studies by the inventors of the present invention, the above problem has been solved by the following means.

(1) A dye having a structure represented by the following general formula (1) (simply indicated as “dye represented by the general formula (1)”) (preferably in the recording layer) is contained. An optical information recording medium. The optical information recording medium is preferably a heat mode type optical information recording medium having a recording layer on the substrate on which information can be recorded by irradiation with laser light.
General formula (1)

In the formula, Ma ²¹ , Ma ²² , Ma ²³ , Ma ²⁴ , Ma ²⁵ and Ma ²⁶ are each independently a substituted or unsubstituted methine group. Ka ²¹ and Ka ²² each independently represents an integer of 0 to 3. 2Q represents two monovalent cations or one divalent cation sufficient to neutralize the charge. When Ka ²¹ and Ka ²² are 2 or 3, a plurality of Ma ²¹ , Ma ²² , Ma ²⁵ and Ma ²⁶ may be the same or different. EWD ₁ , EWD ₂ , EWD ₃ , EWD ₄ , EWD ₃₁ , EWD ₄₁ , EWD ₁₁ , EWD ₂₁ each independently represent an electron withdrawing group, EWD ₃ and EWD ₄ , and EWD ₃₁ and EWD ₄₁ are each , Are connected to each other to form a cyclic structure, L ¹¹ represents a linking group that connects these two cyclic structures, and n represents an integer of 0 to 2. EWD ₁ and EWD ₂ , EWD ₁₁ and EWD ₂₁ may also be independently connected to each other to form a ring structure. However, partial structures including two cyclic structures formed by connecting EWD ₃ and EWD ₄ and EWD ₃₁ and EWD ₄₁ and a linking group (L ¹¹ ) n are the following partial structures L13) and L23). Or L20), two cyclic structures formed by connecting EWD ₁ and EWD ₂ and EWD ₁₁ and EWD ₂₁ to each other form a 4,6-dioxo-1,3-dioxane ring at the same time. Not represent.

(2) In the general formula (1) of (1), including EWD ₃ and EWD ₄ , two cyclic structures formed by linking EWD ₃₁ and EWD ₄₁ , and a linking group (L ¹¹ ) n When the partial structure is represented by L13) and EWD ₁ and EWD ₂ and EWD ₁₁ and EWD ₂₁ are connected to each other to form a cyclic structure, the cyclic structure is the following cyclic structures a) to g), i ), K) to z), and the optical information recording medium according to (1).

However, when the cyclic structure represented by b), l), q) or u) has a substituent, the substituent is a linear or branched, substituted or unsubstituted alkyl having 1 to 12 carbon atoms. Limited to groups.
(3) A portion containing two cyclic structures formed by linking EWD ₃ and EWD ₄ , and EWD ₃₁ and EWD _{41 in} the general formula (1) of (1), and a linking group (L ¹¹ ) n The optical information recording medium according to (1), wherein the structure is not the annular structure represented by the above L13), L23) or L20).
(4) A transparent disk-shaped substrate having a diameter of 120 ± 3 mm or a diameter of 80 ± 3 mm and a thickness of 0.6 ± 0.1 mm on which pregrooves having a track pitch of 0.6 to 0.9 μm are formed. A two-layered product in which a recording layer containing a dye represented by the general formula (1) according to claim 1 is provided on the surface on the side where the pregroove is provided, each recording layer being an inner side The heat mode type optical information recording medium according to (1) or a pregroove with a track pitch of 0.6 to 0.9 μm, which has a thickness of 1.2 ± 0.2 mm. The general formula (1) according to claim 1, wherein a surface of the transparent disk-shaped base having a diameter of 120 ± 3 mm or a diameter of 80 ± 3 mm and a thickness of 0.6 ± 0.1 mm on the side where the pregroove is provided is provided. 1) a laminated body provided with a recording layer containing the dye represented by 1) and a disc-shaped protective plate The thickness of the recording layer are joined such that the inner is characterized in that a 1.2 ± 0.2mm (1) a heat mode type optical information recording medium according.
(5) An information recording method comprising recording information by irradiating the optical information recording medium according to any one of (1) to (4) above with a laser beam having a wavelength of 600 to 700 nm.

  Compared to the comparative dye for low speed recording, the real part n of the complex refractive index is large, and the imaginary part k can provide a dye having the same or smaller value. Further, by using these dyes, it is possible to provide an optical information recording medium excellent in recording characteristics from low speed to high speed. In addition, an optical information recording medium having excellent storage stability can be provided.

The dye of the present invention represented by the general formula (1) will be described in detail.
In the general formula (1), Ma ²¹ , Ma ²² , Ma ²³ , Ma ²⁴ , Ma ²⁵ , and Ma ²⁶ each independently represent a methine group and may have a substituent. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms (for example, methyl, ethyl, i-propyl), a halogen atom (for example, chlorine, bromine, iodine, fluorine), and an alkoxy group having 1 to 20 carbon atoms (for example, Methoxy, ethoxy), aryl groups having 6 to 26 carbon atoms (for example, phenyl, 2-naphthyl), heterocyclic groups having 0 to 20 carbon atoms (for example, 2-pyridyl, 3-pyridyl), and having 6 to 20 carbon atoms. An aryloxy group (eg, phenoxy, 1-naphthoxy, 2-naphthoxy), an acylamino group having 1 to 20 carbon atoms (eg, acetylamino, benzoylamino), a carbamoyl group having 1 to 20 carbon atoms (eg, N, N-dimethylcarbamoyl) ), A sulfo group, a carboxy group, an alkylthio group having 1 to 20 carbon atoms (for example, methylthio), a cyano group, and the like. Further, when the substituent is an alkyl group, this alkyl group may be linked to another methine group to form a 5-membered or 6-membered saturated carbocyclic ring (for example, cyclohexane ring, cyclopentane ring, etc.). The substituent is preferably an alkyl group or an aryl group.
Ma ²¹ , Ma ²² , Ma ²³ , Ma ²⁴ , Ma ²⁵ , Ma ²⁶ are preferably an unsubstituted methine group, or an alkyl group (such as a methyl group or an ethyl group) or an aryl group (such as a phenyl group) as a substituent. Or a methine group that forms a cyclohexane ring or a cyclopentane ring by linking with other methine groups.
Ka ²¹ and Ka ²² each independently represents an integer of 0 to 3. Preferably it is an integer from 1 to 3, more preferably 2 or 3, and most preferably 2.

In the general formula (1), EWD ₁ , EWD ₂ , EWD ₃ , EWD ₄ , EWD ₃₁ , EWD ₄₁ , EWD ₁₁ , EWD ₂₁ each independently represents an electron withdrawing group. Here, the electron withdrawing group is specifically an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a cyano group, an alkylsulfonyl group, an arylsulfonyl group, a sulfamoyl group, or a carbonimidoyl group (—C (= NH)-), and these groups optionally have an arbitrary substituent. The electron withdrawing group is preferably an acyl group, an alkoxycarbonyl group, a carbamoyl group, a sulfamoyl group, an alkyl sulfonyl group, an aryl sulfonyl group, or a carbonimidoyl group (—C (═NH) —).

Examples of the optional substituent include a halogen atom (a fluorine atom, a chloro atom, a bromine atom, or an iodine atom), an alkyl group (a linear, branched, or cyclic alkyl group, including a bicycloalkyl group), an alkenyl group, Alkynyl group, aryl group, heterocyclic group (no matter where it is substituted), acyl group, alkoxycarbonyl group, aryloxycarbonyl group, heterocyclic oxycarbonyl group, carbamoyl group, thiocarbamoyl group, carboxy group or salt thereof, oxalyl Group, oxamoyl group, cyano group, hydroxy group, alkoxy group (including groups containing repeating ethyleneoxy group or propyleneoxy group units), aryloxy group, heterocyclic oxy group, acyloxy group, (alkoxy or aryloxy) carbonyloxy Group, carbamoyloxy , Amino group, (alkyl, aryl, or heterocyclic) amino group, acylamino group, (alkyl, aryl, or heterocyclic) sulfonylamino group, ureido group, thioureido group, imide group, (alkoxy or aryloxy) carbonylamino group , Sulfamoylamino group, nitro group, mercapto group, (alkyl, aryl, or heterocyclic) thio group, (alkyl or aryl) sulfonyl group, sulfo group or a salt thereof, sulfamoyl group, phosphino group, phosphinyl group, silyl group Etc. Here, the salt means a cation such as alkali metal, alkaline earth metal or heavy metal, or an organic cation such as ammonium ion or phosphonium ion.
When these substituents contain carbon atoms, the total number of carbon atoms is preferably 1 to 100, more preferably 1 to 50, and even more preferably 1 to 30.
These substituents may be further substituted with these substituents.

  Preferred examples of the substituent include an alkyl group, an aryl group, a heterocyclic group, a halogen atom, an alkoxycarbonyl group, an (alkyl or aryl) sulfonyl group, an alkoxy group, an alkyl or arylthio group, and the like.

In the general formula (1), EWD ₃ and EWD ₄ , or EWD ₃₁ and EWD ₄₁ are independently connected to each other together with C to form a cyclic structure. Specific examples of the cyclic structure formed here include a) to z) shown below.

  Of these, the cyclic structures are preferably a), b), d), f), g), j), l), q), s), t), u), v), z). More preferably, they are a), d), f), g), j), l), q), s), t), u), v), z).

These cyclic structures may further have an arbitrary substituent. As an arbitrary substituent, the same thing as the substituent of the electron withdrawing group demonstrated previously is mentioned.
Preferred examples of the substituent include a halogen atom, a linear or branched alkyl group, an aryl group (phenyl group or naphthyl group), an alkoxycarbonyl group, an (alkyl or aryl) sulfonyl group, an alkoxy group, an alkyl or arylthio group, and the like. When these contain a carbon atom, 1-18 are preferable and the total carbon number has more preferable 1-12.
However, when the cyclic structure represents the above b), l), q), u), the substituent which they have is preferably an alkyl group, and further, a linear or branched, substituted or substituted group having 1 to 12 carbon atoms. An unsubstituted alkyl group is particularly preferred.

In the general formula (1), EWD ₁ and EWD ₂ , or EWD ₁₁ and EWD ₂₁ may be independently connected to each other to form a cyclic structure. Specific examples of the cyclic structure formed here are the same as those in the case where EWD ₃ and EWD ₄ or EWD ₃₁ and EWD ₄₁ are independently connected to each other to form a cyclic structure. The preferred examples are also the same.

In the general formula (1), L ¹¹ represents a linking group that connects two cyclic structures formed by connecting EWD ₃ and EWD ₄ , and EWD ₃₁ and EWD ₄₁ to each other. n represents an integer of 0 to 2, and when n is 0, it means that the two cyclic structures are directly connected without a linking group. In this case (when directly connected), specifically, two cyclic structures may form a spiro ring structure on one carbon atom included in the cyclic structure, and two cyclic structures included in the cyclic structure. On the atom, two cyclic structures may be connected in a condensed form. When n represents 2, it represents that two cyclic structures are simultaneously connected by two linking groups. In this case, one carbon atom included in each cyclic structure may be simultaneously connected by two linking groups to form a spiro ring structure, and two atoms included in each cyclic structure may be The linking groups may be linked to each other (in any case, the linking group itself further forms a cyclic structure).

Specifically, L ¹¹ is a single bond, an alkylene group (having 1 to 20 carbon atoms such as methylene, ethylene, propylene, butylene, pentylene), an arylene group (having 6 to 26 carbon atoms such as phenylene or naphthylene), an alkenylene group ( C2-C20, for example ethenylene, propenylene), alkynylene groups (C2-C20, for example ethynylene, propynylene), heterylene groups (C1-26, for example 6-chloro-1,3,5-triazyl-2) , 4-diyl group, pyrimidine-2,4-diyl group), —SO ₂ —, —SO—, —S—, —O—, —CO—, —N (R ¹⁰⁵ ) — It represents a linking group having 0 to 100 carbon atoms, preferably 1 to 20 carbon atoms, which is composed of one or more. Examples of linking groups configured in combination include -CO-N (R ¹⁰¹ )-, -CO-O-, -SO ₂ -N (R ¹⁰² )-, -SO ₂ -O-, -N (R ¹⁰³ ) -CO-N (R ¹⁰⁴ )-, -CO-alkylene group-CO-, -CO-arylene group-CO-, -CO-N (R ¹⁰¹ ) -arylene group-CO-N (R ¹⁰¹ )- , Etc. R ¹⁰¹ , R ¹⁰² , R ¹⁰³ , R ¹⁰⁴ , and R ¹⁰⁵ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. The linking group represented by L ¹¹ may have an arbitrary substituent.

L ¹¹ is a single bond, —O—, —CO—, —N (R ¹⁰⁵ ) —, —SO ₂ —, an alkylene group, an arylene group (particularly a phenylene group), or a combination of these groups. A linking group is preferred.

In the general formula (1), a partial structure (n that includes two cyclic structures formed by linking EWD ₃ and EWD ₄ , and EWD ₃₁ and EWD ₄₁ , and a linking group:-(L ¹¹ ) n- A specific example of this is also shown below.

However, a partial structure including two cyclic structures formed by connecting EWD ₃ and EWD ₄ and EWD ₃₁ and EWD ₄₁ and a linking group (L ¹¹ ) n is represented by the following partial structure. In other words, when represented by the following L13), L20), and L23), two cyclic structures formed by connecting EWD ₁ and EWD ₂ and EWD ₁₁ and EWD ₂₁ to each other are It does not represent a 6-dioxo-1,3-dioxane ring (that is, the cyclic structure represented by j).

In the general formula (1), 2Q represents two monovalent cations or one divalent cation sufficient to neutralize the charge. The cation may be an ion made of an inorganic compound or an ion made of an organic compound. Examples of the monovalent or divalent cation include metal ions such as sodium ion and potassium ion, quaternary ammonium ions, oxonium ions, sulfonium ions, phosphonium ions, selenonium ions, and onium ions such as iodonium ions. It is done.
Preferred is an onium ion, and more preferred is a quaternary ammonium ion. Of the quaternary ammonium ions, 4,4′-bipyridinium cation represented by general formula (I-4) in JP-A No. 2000-52658 and JP-A No. 2002-59652 are particularly preferable. 4,4′-bipyridinium cation. Specific examples of these preferred cation structures are shown in the following (Q1 to Q5).

Next, a more preferable range of the dye represented by the general formula (1) of the present invention will be described.
In the general formula (1), it is more preferable that EWD ₁ and EWD ₂ , or EWD ₁₁ and EWD ₂₁ are independently connected to each other to form a cyclic structure.
In the general formula (1), a partial structure including two cyclic structures formed by linking EWD ₃ and EWD ₄ , and EWD ₃₁ and EWD ₄₁ , and a linking group (L ¹¹ ) n is L13). In the case where EWD ₁ and EWD ₂ , and EWD ₁₁ and EWD ₂₁ are connected to each other to form a cyclic structure, the cyclic structures are the following cyclic structures a) to g), i), k) to z ) Is more preferable.

However, when the cyclic structure represented by the above b), l), q), u) has a substituent, the substituent is a linear or branched, substituted or unsubstituted group having 1 to 12 carbon atoms. Of the alkyl group.
More preferably, the cyclic structure is represented by the above a), b), d), f), g), l), q), s), t), u), v), z). More preferably, it is the time represented by a), d), f), g), s), t), u), v), z).
In the general formula (1), partial structures including two cyclic structures formed by linking EWD ₃ and EWD ₄ , EWD ₃₁ and EWD ₄₁ , and a linking group (L ¹¹ ) n are L13), L23 ) Or L20) is also preferred.

  Although the preferable example of the pigment | dye of the structure represented by General formula (1) of this invention below is given, this invention is not limited to these.

  The dye having the structure represented by the general formula (1) of the present invention can be easily synthesized by a known synthesis method.

Synthesis Example 1 (Synthesis of Exemplified Compound 1)
Exemplified Compound 1 was synthesized according to Synthesis Scheme 1.

Synthesis of Synthesis Intermediate [1] 1,4-Cyclohexadione (22.43 g, 0.2 mol) and malonic acid (41.62 g, 0.4 mol) were dissolved in acetic anhydride (85 ml) and concentrated sulfuric acid (7 0.0 ml, 0.12 mol) was added and the mixture was stirred in an ice bath for 2 hours. The mixture was further stirred at room temperature for 2 hours. As the reaction progressed, light brown crystals were precipitated, which were filtered and washed with acetic acid and then with water to obtain 10.8 g of crystals of the synthetic intermediate [1] (yield 19.0%). The structure was confirmed by MS and NMR. ¹ H-NMR (DMSO-d ₆ ) δ (ppm): 4.07 (s, 4H), 2.20 (s, 8H)

Synthesis of Synthesis Intermediate [2] Sulfuryl chloride (16.1 ml, 0.2 mol) was added to 100 ml of chloroform, and the internal temperature was cooled to -10 ° C. Pyridine (65 ml, 0.8 mol) was added dropwise while maintaining the internal temperature at 0 ° C. or lower. Subsequently, a solution in which n-propylamine (30 g, 0.5 mol) was dissolved in 120 ml of chloroform was dropped. After performing the reaction at 0 ° C. or lower for 2 hours, the reaction was performed at room temperature for 2 hours. After the reaction solution was washed with water twice, chloroform was distilled off under reduced pressure, and n-hexane was added for crystallization. The precipitated crystals were filtered to obtain 11.3 g of the desired synthetic intermediate [2] (yield 31.3%). The structure was confirmed by NMR. ¹ H-NMR (CDCl ₃ ) δ (ppm): 4.30 (t, 2H), 3.00 (q, 4H), 1.69 to 1.51 (m, 4H), 0.93 (t, 6H)

Synthesis of Synthesis Intermediate [3] 35 ml of toluene was added to malonic acid chloride (6.26 g, 44.4 mmol). Synthetic intermediate [2] (8.0 g, 44.4 mmol) was added with stirring at room temperature. After reacting for 4 hours at a reaction temperature of 65 to 75 ° C., the reaction solution was cooled to room temperature. The reaction mixture was added to ice water and extracted with ethyl acetate. After washing with water three times, ethyl acetate was distilled off under reduced pressure to obtain 10.8 g of oily target product, synthetic intermediate [3] (yield 99.3%). The structure was confirmed by MS and NMR. ¹ H-NMR (CDCl ₃ ) δ (ppm): 3.91 (s, 2H), 3.80 (t, 4H), 1.85 to 1.62 (m, 4H), 0.96 (t, 6H)

Synthesis of Synthetic Intermediate [5] N, N′-1,5-pentadien-1-yl-5-ylidenedianiline hydrochloride [4] (11.5 g, 40.4 mmol) was added to 150 ml of methanol and triethylamine (8. 5 ml, 60.6 mmol) was added and dissolved at room temperature. While stirring at room temperature, a solution of synthetic intermediate [3] (10.0 g, 40.4 mmol) dissolved in 20 ml of methanol was added dropwise over 40 minutes. The mixture was stirred at room temperature for 1 hour, and the precipitated crystals were filtered to obtain 7.3 g of the target synthetic intermediate [5] (yield 44.8%). The structure was confirmed by NMR. ¹ H-NMR (CDCl ₃ ) δ (ppm): 7.95 (d, 1H), 7.69 (br, 1H), 7.60-7.17 (m, 5H), 7.16-7.03 (m, 1H), 6.99 (d, 2H ), 6.00 (t, 1H), 3.83 (t, 4H), 1.87 to 1.64 (m, 4H), 0.94 (t, 6H)

Synthesis of Synthetic Intermediate [6] To synthetic intermediate [1] (2.46 g, 8.66 mmol), 40 ml of N, N-dimethylformamide and triethylamine (3.6 ml, 25.8 mmol) were added and dissolved at room temperature. Under stirring at room temperature, powder of synthetic intermediate [5] (7.0 g, 17.3 mmol) was added in portions. After reacting at room temperature for 2 hours, ethyl acetate and water were added, and dilute hydrochloric acid was added to adjust the pH to 5. After performing twice with saturated saline, ethyl acetate was distilled off under reduced pressure. Purification by column chromatography yielded 2.05 g of the target synthetic intermediate [6] (yield 25.0%). The structure was confirmed by MS and NMR. ¹ H-NMR (DMSO-d ₆ ) δ (ppm): 7.80 to 7.62 (m, 4H), 7.60 to 7.50 (m, 2H), 7.39 to 7.12 (m, 4H), 3.70 (t, 8H), 2.02 (s, 8H), 19 ~ 1.52 (m, 8H), 0.88 (t, 12H)

Synthesis of Exemplary Compound 1 4,4′-bipyridinium salt 7 (0.156 g, 0.28 mmol) was dissolved in 85 ml of methanol at room temperature. While stirring at room temperature, a solution of synthetic intermediate [6] (0.25 g, 0.28 mmol) dissolved in 10 ml of methanol was added dropwise over 10 minutes. After reacting at room temperature for 1 hour, the precipitated crystals were filtered to obtain 0.32 g of the target exemplified compound 1 (yield 82.4%). The structure was confirmed by NMR. ¹ H-NMR (DMSO-d ₆ ) δ (ppm): 10.72 (s, 2H), 9.68 (d, 4H), 9.00 (d, 4H), 7.91 (s, 2H), 7.81 to 7.60 (m, 10H ), 7.59 to 7.44 (m, 6H), 7.43 to 7.10 (m, 8H), 3.70 (t, 8H), 2.00 (s, 8H), 1.69 to 1.52 (m, 8H), 0.86 (t, 12H)

Synthesis Example 2 (Synthesis of Exemplified Compound 2)
In the synthesis method of Example Compound 1 shown in Synthesis Example 1, Example Compound 2 was synthesized by the same method as Synthesis Example 1 using sec-butylamine instead of using n-propylamine as a starting material. The structure of Example Compound 2 was confirmed by NMR. ¹ H-NMR (DMSO-d ₆ ) δ (ppm): 10.72 (s, 2H), 9.68 (d, 4H), 9.00 (d, 4H), 7.91 (s, 2H), 7.80 to 7.58 (m, 10H) ), 7.55 to 7.46 (m, 6H), 7.45 to 7.34 (m, 2H), 7.30 to 7.09 (m, 6H), 4.60 to 4.46 (m, 4H), 2.00 (s, 8H), 2.02 to 1.89 (m , 4H), 1.71-1.59 (m, 4H), 1.38 (d, 12H), 0.82 (t, 12H)

  The coloring matter represented by the general formula (1) according to the present invention may be used alone or in combination of two or more. Moreover, you may use together the pigment | dye (compound) concerning this invention, and other pigment compounds.

The information recording medium of the present invention is not particularly limited as long as it has the dye represented by the general formula (1) as a recording layer. However, when the optical information recording medium of the present invention is applied to a CD-R. Is a recording containing a dye represented by the general formula (1) on a transparent disk-like substrate having a thickness of 1.2 ± 0.2 mm on which pregrooves having a track pitch of 1.4 to 1.8 μm are formed. A structure having a layer, a light reflection layer, and a protective layer in this order is preferable. Moreover, when applying to DVD-R, it is preferable that it is the following two aspects.

(1) A pigment represented by the general formula (1) is contained on a transparent disk-shaped substrate having a thickness of 0.6 ± 0.1 mm on which pregrooves having a track pitch of 0.6 to 0.9 μm are formed. An optical information recording medium configured such that two laminates each provided with a recording layer and a light reflecting layer are joined so that the recording layers are on the inner side and have a thickness of 1.2 ± 0.2 mm.

(2) The pigment represented by the general formula (1) is contained on a transparent disk-shaped substrate having a thickness of 0.6 ± 0.1 mm on which pregrooves having a track pitch of 0.6 to 0.9 μm are formed. A laminated body provided with a recording layer and a light reflecting layer and a transparent disk-shaped protective substrate having the same shape as the disk-shaped substrate of the laminated body are joined so that the recording layer is on the inside, and a thickness of 1. An optical information recording medium configured to be 2 ± 0.2 mm. In the DVD-R type optical information recording medium, a protective layer may be further provided on the light reflecting layer.

  The information recording medium of the present invention can be manufactured, for example, by the method described below. The substrate (including the protective substrate) can be arbitrarily selected from various materials used as a substrate of a conventional information recording medium. Examples of the substrate material include glass; polycarbonate; acrylic resin such as polymethyl methacrylate; vinyl chloride resin such as polyvinyl chloride and vinyl chloride copolymer; epoxy resin; amorphous polyolefin and polyester; You may use them together. These materials can be used as a film or as a rigid substrate. Among the above materials, polycarbonate is preferable from the viewpoint of moisture resistance, dimensional stability, price, and the like.

  An undercoat layer may be provided on the surface of the substrate on which the recording layer is provided for the purpose of improving the flatness, improving the adhesive force, and preventing the recording layer from being altered. Examples of the material for the undercoat layer include polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleic anhydride copolymer, polyvinyl alcohol, N-methylol acrylamide, styrene / vinyl toluene copolymer, chlorosulfonated. High molecular substances such as polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, polyethylene, polypropylene, polycarbonate; and silane coupling agents And the like. The undercoat layer is formed by dissolving or dispersing the above substances in an appropriate solvent to prepare a coating solution, and then applying this coating solution to the substrate surface by a coating method such as spin coating, dip coating, or extrusion coating. can do.

  On the substrate (or undercoat layer), irregularities (pregrooves) representing information such as tracking grooves or address signals are formed. The pregroove is preferably formed directly on the substrate at the track pitch when a resin material such as polycarbonate is injection molded or extruded. Further, the pregroove may be formed by providing a pregroove layer. As a material of the pregroove layer, a mixture of at least one monomer (or oligomer) of monoester, diester, triester and tetraester of acrylic acid and a photopolymerization initiator can be used. For example, the pregroove layer is formed by, first, applying a liquid mixture comprising the above acrylate ester and a polymerization initiator on a precisely formed master (stamper), and further placing a substrate on the coating liquid layer. After that, the coating layer is cured by irradiating ultraviolet rays through the substrate or the mother die, and the substrate and the coating layer are fixed. Subsequently, it can obtain by peeling a board | substrate from a mother mold.

On the surface of the substrate (or undercoat layer) on which the pregroove is formed, a recording layer containing the dye of claim 1, preferably the dye compound represented by the general formula (1) according to the present invention. Provided.
The recording layer can further contain various anti-fading agents for improving light resistance. Representative examples of the anti-fading agent include metal complexes, diimmonium salts, aminium salts represented by general formula (III), (IV) or (V) described in JP-A-3-224793, and JP-A-2-300287. And nitroso compounds disclosed in JP-A-2-300288 and TCNQ derivatives disclosed in JP-A-10-151861.

  The recording layer is formed by preparing a coating solution by dissolving the dye according to the present invention, and optionally, a quencher, a binder, etc. in a solvent, and then coating the coating solution on the substrate surface to form a coating film. This can be done by drying. Examples of the solvent for the coating solution for forming the dye recording layer include esters such as butyl acetate, ethyl lactate and cellosolve acetate; ketones such as methyl ethyl ketone, cyclohexanone and methyl isobutyl ketone; chlorinated carbonization such as dichloromethane, 1,2-dichloroethane and chloroform. Hydrogen; Amides such as dimethylformamide; Hydrocarbons such as cyclohexane; Ethers such as tetrahydrofuran, ethyl ether and dioxane; Alcohols such as ethanol, n-propanol, isopropanol, n-butanol and diacetone alcohol; 2,2,3 Fluorine solvents such as 1,3-tetrafluoropropanol; glycosyl such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether And the like ethers. The said solvent can be used individually or in combination of 2 or more types in consideration of the solubility of the compound to be used. Various additives such as an antioxidant, a UV absorber, a plasticizer, and a lubricant may be further added to the coating solution depending on the purpose.

  Examples of binders include natural organic polymer materials such as gelatin, cellulose derivatives, dextran, rosin, rubber; and hydrocarbon resins such as polyethylene, polypropylene, polystyrene, polyisobutylene; polyvinyl chloride, polyvinylidene chloride, Vinyl resins such as polyvinyl chloride and polyvinyl acetate copolymers; Acrylic resins such as polymethyl acrylate and polymethyl methacrylate; Polyvinyl alcohol, chlorinated polyethylene, epoxy resins, butyral resins, rubber derivatives, phenol-formaldehyde resins And a synthetic organic polymer such as an initial condensate of a thermosetting resin. When a binder is used in combination as a material for the recording layer, the amount of the binder used is generally in the range of 0.01 to 50 times (mass ratio), preferably 0.1 to 5 times the amount of the dye. It is in the range of (mass ratio). The pigment concentration of the coating solution thus prepared is generally in the range of 0.01 to 10% by mass, preferably in the range of 0.1 to 5% by mass.

  Examples of the coating method include a spray method, a spin coating method, a dip method, a roll coating method, a blade coating method, a doctor roll method, and a screen printing method. The recording layer may be a single layer or a multilayer. The thickness of the recording layer is generally in the range of 20 to 500 nm, preferably in the range of 50 to 300 nm.

  A reflective layer is provided on the recording layer for the purpose of improving reflectivity during information reproduction. The light-reflective substance that is the material of the reflective layer is a substance having a high reflectivity with respect to laser light. Examples thereof include Mg, Se, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W. , Mn, Re, Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Si, Ge, Te, Pb, Po, Sn, Bi And metals such as semimetals and stainless steels. Of these, Cr, Ni, Pt, Cu, Ag, Au, Al, and stainless steel are preferable, and Ag is particularly preferable. These substances may be used alone or in combination of two or more or as an alloy. The reflective layer can be formed on the recording layer, for example, by vapor deposition, sputtering or ion plating of the reflective material. The thickness of the reflective layer is generally in the range of 10 to 300 nm, preferably in the range of 50 to 200 nm.

A protective layer may be provided on the reflective layer for the purpose of physically and chemically protecting the recording layer and the like. This protective layer may be provided on the side where the base recording layer is not provided for the purpose of improving scratch resistance and moisture resistance. Examples of the material used for the protective layer include inorganic substances such as SiO, SiO ₂ , MgF ₂ , SnO ₂ , and Si ₃ N _4, and organic substances such as thermoplastic resins, thermosetting resins, and UV curable resins. be able to. The protective layer can be formed, for example, by laminating an adhesive layer on the reflective layer and / or the substrate with a film obtained by plastic extrusion. Or you may provide by methods, such as vacuum evaporation, sputtering, and application | coating. In the case of a thermoplastic resin or a thermosetting resin, it can also be formed by preparing a coating solution by dissolving in an appropriate solvent, and then applying and drying the coating solution. In the case of a UV curable resin, it can also be formed by preparing a coating solution as it is or by dissolving it in a suitable solvent, coating the coating solution, and curing it by irradiating with UV light. In these coating liquids, various additives such as an antistatic agent, an antioxidant, and a UV absorber may be added according to the purpose. The thickness of the protective layer is generally in the range of 0.1 to 100 μm. Through the above steps, a laminate in which a recording layer, a reflective layer, and a protective layer as required can be formed on a substrate can be produced. A two-layered laminate is produced as described above, and these are bonded together with an adhesive so that each recording layer is on the inside, thereby producing a DVD-R type information recording medium having two recording layers. Can be manufactured. Further, a DVD having a recording layer only on one side is obtained by adhering the obtained laminate and a disk-shaped protective substrate having substantially the same dimensions as the substrate of the laminate so that the recording layer is inside. -R type information recording medium can be manufactured.

  The information recording method of the present invention is performed, for example, as follows using the above information recording medium. First, a laser beam for recording such as a semiconductor laser beam is irradiated from the substrate side while rotating the information recording medium at a constant linear velocity or a constant angular velocity. This light irradiation forms a cavity at the interface between the recording layer and the reflective layer (the formation of the cavity is accompanied by deformation of the recording layer or the reflective layer, or deformation of both layers), or the substrate is thin. It is considered that information is recorded when the refractive index is changed due to the deformation of the recording layer or due to discoloration, change in association state, or the like. As the recording light, a semiconductor laser beam having an oscillation wavelength in the range of 770 to 790 nm for the CD-R type and 600 nm to 700 nm (preferably 620 to 680 nm, more preferably 630 to 660 nm) for the DVD-R type is used. . Reproduction of information recorded as described above is performed by irradiating a semiconductor laser beam having the same wavelength as that during recording from the substrate side while rotating the information recording medium at the same constant linear velocity as above and detecting the reflected light. This can be done.

[Example]
Examples will be described below, but the present invention is of course not limited thereto.

Evaluation of Optical Constants The optical properties (real part n and imaginary part k of the complex refractive index) of the dye compound of the present invention were evaluated by reflection spectroscopic ellipsometry. A spin coat film formed on a glass substrate was used as a sample for optical property evaluation used for spectroscopic ellipsometry. This spin coat film can be prepared by dissolving each compound in 2,2,3,3, -tetrafluoropropanol so that the solution concentration is 25 mM and casting the solution on a rotating glass substrate.

  The optical properties of the spin coat film of Example Compound 2 in the present invention were evaluated. From the obtained results, the values of n and k at 660 nm are shown in Table 1 below.

  Next, an embodiment as an optical information recording medium is shown.

[Create optical recording media]
By injection molding, a polycarbonate resin was formed on a substrate having a spiral groove (depth 130 nm, width 310 nm, track pitch 0.74 μm) and a thickness of 0.6 mm and a diameter of 120 mm.
A coating solution prepared by dissolving 1.25 g of the dye compound 2 of the present invention in 100 ml of 2,2,3,3-tetrafluoropropanol was prepared, and this coating solution was applied onto the surface on which the groove of the substrate was formed by spin coating. Then, a dye layer was formed.
Next, silver is sputtered on each dye-coated surface to form a reflective layer having a film thickness of about 150 nm, and then an ultraviolet curable resin (Dicure Clear SD640 manufactured by Dainippon Ink and Chemicals) is used as an adhesive. A disk was prepared by bonding to a 6 mm thick dummy substrate.
(Comparative Example 1)
A disk was produced in the same manner as in Example 2 except that the following comparative compound (1) was used instead of the dye compound 2.
(Comparative Example 2)
A disk was produced in the same manner as in Example 2 except that the following comparative compound (2) was used instead of the dye compound 2.
[Evaluation of optical recording media]
Using a DDU1000 and a multi-signal generator (manufactured by Pulstec Corp., laser wavelength = 660 nm, aperture ratio = 0.60), the transfer rate is 1 × speed (11.08 Mbps), 8 × speed (88.64M), 10 × speed (110. 8-16 modulation signal was recorded at 8 Mbps).
The recording strategy used is shown in Table 2. Recording was performed with 1 type of 1 × speed recording and 10 × speed recording, and with 8 × speed recording of 2 types having greatly different pulse widths.
The recording power was set to a recording power with the smallest jitter in each medium. Thereafter, reproduction was performed using a laser having the same wavelength as the recording laser wavelength, and jitter was measured. The results are shown in Table 3.
The example has lower jitter and higher reflectivity at 1 × speed, 8 × speed, and 10 × speed than the comparative example.
Further, in the 8X recording characteristics, the jitter was better in the examples in all the recording strategies having greatly different pulse widths.
(Table 2) Recording strategy

(Table 3) Recording characteristics evaluation results

Disc samples 201 to 212 were prepared in the same manner as in Example 2 except that the dye compounds shown in Table 4 below were used instead of the dye compound 2. The recording / reproducing performance was evaluated in exactly the same manner as in Example 2. After production, the sample was stored for 10 days under a forced deterioration condition of 80 ° C. and a relative humidity of 80%, and then the reproduction performance was evaluated again. The results are shown in Table 4. It turns out that the pigment | dye of this invention is excellent in storage stability compared with a comparative compound. In Table 4,
○ When the PI error value at 1 × speed recording exceeds 280 Δ When the PI error value at 1 × speed recording is 100 to 280 × When the PI error value at 1 × speed recording is less than 100

Claims (3)

An optical information recording medium comprising a dye having a structure represented by the general formula (1).
General formula (1)

In the formula, Ma ²¹ , Ma ²² , Ma ²³ , Ma ²⁴ , Ma ²⁵ and Ma ²⁶ are each independently a substituted or unsubstituted methine group. Ka ²¹ and Ka ²² each independently represents an integer of 0 to 3. 2Q represents two monovalent cations or one divalent cation sufficient to neutralize the charge. When Ka ²¹ and Ka ²² are 2 or 3, a plurality of Ma ²¹ , Ma ²² , Ma ²⁵ and Ma ²⁶ may be the same or different. EWD ₁ , EWD ₂ , EWD ₃ , EWD ₄ , EWD ₃₁ , EWD ₄₁ , EWD ₁₁ , EWD ₂₁ each independently represent an electron withdrawing group, EWD ₃ and EWD ₄ , and EWD ₃₁ and EWD ₄₁ are each , Are connected to each other to form a cyclic structure, L ¹¹ represents a linking group that connects these two cyclic structures, and n represents an integer of 0 to 2. EWD ₁ and EWD ₂ , EWD ₁₁ and EWD ₂₁ may also be independently connected to each other to form a ring structure. However, partial structures including two cyclic structures formed by connecting EWD ₃ and EWD ₄ and EWD ₃₁ and EWD ₄₁ and a linking group (L ¹¹ ) n are the following partial structures L13) and L23). Or L20), two cyclic structures formed by connecting EWD ₁ and EWD ₂ and EWD ₁₁ and EWD ₂₁ to each other form a 4,6-dioxo-1,3-dioxane ring at the same time. Not represent.

In the general formula (1) of claim 1, a partial structure including two cyclic structures formed by linking EWD ₃ and EWD ₄ , and EWD ₃₁ and EWD ₄₁ , and a linking group (L ¹¹ ) n. In the case where EWD ₁ and EWD ₂ , and EWD ₁₁ and EWD ₂₁ are connected to each other to form a cyclic structure, the cyclic structure is represented by the following cyclic structures a) to g), i), k The optical information recording medium according to claim 1, wherein the optical information recording medium is represented by any one of (1) to (z).

However, when the cyclic structure represented by b), l), q), or u) has a substituent, the substituent is a linear or branched, substituted or unsubstituted group having 1 to 12 carbon atoms. Limited to alkyl groups. A partial structure including two cyclic structures formed by linking EWD ₃ and EWD ₄ and EWD ₃₁ and EWD ₄₁ in the general formula (1) and a linking group (L ¹¹ ) n is L13). The optical information recording medium according to claim 1, wherein the optical information recording medium is not a ring structure represented by L23) or L20).