JP2006150841A - Optical recording material and optical recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical recording material for an optical recording medium, in which high-speed recording is possible and, at the same time, jitters at high-speed recording can be fully reduced. <P>SOLUTION: In the optical recording material used in an optical recording medium, to which the recording of information is possible by the irradiation of light, styryl base coloring matter expressed by general formula (1) is included. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical recording material used for an optical recording medium for recording information by light irradiation, and an optical recording medium.

  As optical recording media, optical recording disks such as CD-R (recordable CD) and DVD-R (recordable DVD) are already widely used. In recent years, this optical recording medium has been required to have a higher recording density, and in order to meet such a demand, the wavelength of recording / reproducing light has been shortened. Examples of such high-density recording media include DVD-R and DVD + R that can perform recording and reproduction at 650 nm.

Further, in such an optical recording medium, high speed and high speed are demanded, and it is required to cope with a high speed of 14 m / sec (corresponding to 4 times speed) or more. Cyanine dyes (see, for example, Patent Documents 1 to 3), styryl dyes (see, for example, Patent Document 4) and the like have been proposed as optical recording materials used for the recording layer of such a high density / high speed recording medium. ing.
JP 2003-231359 A JP 2003-237240 A JP-A-9-39394 JP 2002-283719 A

  By the way, in order to increase the recording speed, it is desirable to use a dye with higher sensitivity. Usually, however, fluctuation of the reproduction signal in the time direction (jitter) increases as the sensitivity of the dye increases. As a result, the recording characteristics tend to deteriorate.

  For example, in the case of an optical recording medium using a conventional optical recording material as described in Patent Documents 1 to 4, it is difficult to sufficiently reduce jitter during high-speed recording. Found.

  The present invention has been made in view of the above-described problems of the prior art, and is capable of high-speed recording, and an optical recording material for an optical recording medium that can sufficiently reduce jitter during high-speed recording. And an optical recording medium.

  As a result of intensive studies to achieve the above object, the present inventors have found that the above object can be achieved if the optical recording material contains a styryl dye having a specific structure, The present invention has been completed.

［式（１）中、Ｒ^１は炭素数１〜６のアルキル基又はアリール基を示し、Ｒ^２は炭素数１〜２のアルキル基又は置換基を有していてもよいベンジル基を示し、Ｘ^１及びＸ^２はそれぞれ独立にハロゲン原子、炭素数１〜２のアルキル基又は炭素数１〜２のオキシアルキル基を示し、Ｘ^３は炭素数１〜４のアルキル基又はアルキルアミノ基を示し、ｐ、ｑ及びｒはそれぞれ独立に０〜４の整数を示す。なお、ｐが２以上の場合、複数存在するＸ^１は同一でも異なっていてもよく、Ｘ^１同士連結して環を形成してもよい。また、ｑが２以上の場合、複数存在するＸ^２は同一でも異なっていてもよく、Ｘ^２同士連結して環を形成してもよい。更に、ｒが２以上の場合、複数存在するＸ^３は同一でも異なっていてもよく、Ｘ^３同士連結して環を形成してもよい。］ That is, the present invention is an optical recording material used for an optical recording medium capable of recording information by light irradiation, and contains a styryl dye represented by the following general formula (1). An optical recording material is provided.

[In formula (1), R ¹ represents an alkyl group or an aryl group having 1 to 6 carbon atoms, R ² represents a benzyl group which may have an alkyl group or a substituent having 1 to 2 carbon atoms, X ¹ and X ² each independently represent a halogen atom, an alkyl group having 1 to 2 carbon atoms, or an oxyalkyl group having 1 to 2 carbon atoms, and X ³ represents an alkyl group having 1 to 4 carbon atoms or an alkylamino group. , P, q and r each independently represents an integer of 0 to 4. When p is 2 or more, a plurality of X ¹ may be the same or different, and X ¹ may be linked together to form a ring. When q is 2 or more, a plurality of X ² may be the same or different, and X ² may be linked to form a ring. Furthermore, when r is 2 or more, a plurality of X ³ may be the same or different, and X ³ may be linked to form a ring. ]

  According to such an optical recording material, when the optical recording medium is constituted by containing the styryl dye having the specific structure, high-speed recording of, for example, 4 × speed or more is possible. Jitter can be sufficiently reduced as compared with the case of using a conventional optical recording material.

［式（２）中、Ｂ^１及びＢ^２はそれぞれ独立に芳香族環を構成する原子群を示し、Ｙ^１及びＹ^２はそれぞれ独立に、１以上の活性水素原子を有し、置換基を有していてもよい官能基を示す。］ The optical recording material of the present invention preferably further contains a chelate compound in which an azo compound represented by the following general formula (2) is coordinated to a metal.

[In the formula (2), B ¹ and B ² each independently represent an atomic group constituting an aromatic ring, Y ¹ and Y ² each independently have one or more active hydrogen atoms, The functional group which may have is shown. ]

  Such an optical recording material can obtain excellent light resistance when an optical recording medium is constituted by containing a chelate compound composed of an azo compound having a specific structure and a metal together with the styryl dye described above. .

  The present invention also provides an optical recording medium capable of recording information by light irradiation, comprising an optical recording medium containing the optical recording material of the present invention.

  Since such an optical recording medium uses the optical recording material of the present invention for the recording layer, for example, high-speed recording of 4 times or more speed is possible, and the jitter at that time is compared with that of a conventional optical recording medium. It can be sufficiently reduced.

  According to the present invention, an optical recording material and an optical recording medium for an optical recording medium capable of high-speed recording (for example, 4 × speed or more) and capable of sufficiently reducing jitter during high-speed recording are provided. Can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the following description, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

(Optical recording material)
The optical recording material of the present invention is an optical recording material used for an optical recording medium capable of recording information by light irradiation, and contains a styryl dye represented by the following general formula (1). .

Here, in the above general formula (1), R ¹ represents an alkyl group or an aryl group having 1 to 6 carbon atoms, preferably an alkyl group having 1 to 5 carbon atoms. Of these, the alkyl group may be linear, branched or cyclic. Examples of the aryl group include a phenyl group, a pentaenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptaenyl group, a biphenylenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, and a pyrenyl group.

R ² represents an alkyl group having 1 to 2 carbon atoms or a benzyl group which may have a substituent, and is preferably a benzyl group which may have a substituent.

X ¹ and X ² each independently represent a halogen atom, an alkyl group having 1 to 2 carbon atoms or an oxyalkyl group having 1 to 2 carbon atoms, and are a chlorine atom, a bromine atom, a fluorine atom, a methyl group or a methoxy group. It is preferable.

X ³ represents an alkyl group having 1 to 4 carbon atoms or an alkylamino group, and is preferably an alkylamino group. Of these, the alkylamino group is not particularly limited as long as it has a direct or unsubstituted alkyl group bonded to the nitrogen atom, and the alkyl group is preferably an alkyl group having 1 or 2 carbon atoms, particularly methyl. Groups and ethyl groups are preferred.

p, q and r each independently represent an integer of 0 to 4, preferably 1 or 2. When p is 2 or more, a plurality of X ¹ may be the same or different, and X ¹ may be linked together to form a ring. When q is 2 or more, a plurality of X ² may be the same or different, and X ² may be linked to form a ring. Furthermore, when r is 2 or more, a plurality of X ³ may be the same or different, and X ³ may be linked to form a ring.

  Preferable examples of the styryl dye represented by the general formula (1) include compounds represented by the following formulas (3-1) to (3-12).

  According to the optical recording material of the present invention containing these styryl dyes, when an optical recording medium is formed, high-speed recording at, for example, a quadruple speed or more is possible, and jitter at high-speed recording is sufficiently reduced. be able to.

  The method for synthesizing these styryl dyes according to the present invention is not particularly limited, and can be synthesized according to a conventional method.

  Furthermore, the optical recording material preferably contains a chelate compound formed by coordination of the azo compound represented by the general formula (2) to a metal, together with the styryl dye.

Here, in the general formula (2), B ¹ and B ² each independently represent an atomic group constituting an aromatic ring. That is, the atomic groups B ¹ and B ² each form an aromatic ring together with two carbon atoms involved in the double bond. Specific examples of the aromatic ring include a benzene ring, naphthalene ring, pyridine ring, thiazole ring, benzothiazole ring, oxazole ring, benzoxazole ring, quinoline ring, imidazole ring, pyrazine ring, pyrrole ring, and indolenine ring. And benzoindolenine ring. Among them, a benzene ring and a naphthalene ring are preferable.

The above aromatic group may have a substituent in addition to a group having active hydrogen such as -Y ¹ and -Y ² . Such substituents include alkyl groups, aryl groups, aralkyl groups, acyl groups, alkoxy groups, alkenyl groups, halogen atoms, hydroxy groups, carboxyl groups, carboxylic acid ester groups, sulfone groups, sulfonic acid ester groups, sulfamoyl groups, sulfones. Examples include an amide group, a carbamoyl group, an amino group, an amide group, an alkylthio group, an alkylazomethine group, and a nitro group. When two or more substituents are bonded to adjacent carbon atoms of the aromatic ring, the substituents may be linked to form a ring.

  Of the substituents on the aromatic ring, the alkyl group is preferably an alkyl group having 1 to 12 carbon atoms. The alkyl group may be linear or branched and may be a combination of two or more thereof. In addition, a substituent such as a halogen atom or an alkoxy group may be bonded to the alkyl group.

  Examples of the aryl group include a phenyl group and a tolyl group. The total number of carbon atoms in the aryl group is preferably 6-10. The aryl group may be substituted or unsubstituted.

  Examples of the acyl group include an acetyl group, a propionyl group, and a butyryl group. The total carbon number of the acyl group is preferably 2-5.

  Examples of the aralkyl group include a benzyl group, a hydroxybenzyl group, and a methylbenzyl group. The total number of carbon atoms in the aralkyl group is preferably 7-10.

  As an alkoxy group, a C1-C4 thing is preferable and a methoxy group, an ethoxy group, a propoxy group, a pentafluoropropoxy group etc. are mentioned.

  The alkenyl group may be linear or branched, and specific examples include a vinyl group, an allyl group, a propenyl group, a butenyl group, and a pentenyl group. Those having a total carbon number of 2 to 10 are preferred.

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

  The carboxylic acid ester group preferably has 2 to 10 carbon atoms in total, and examples thereof include a methoxycarbonyl group, an ethoxycarbonyl group, a propoxycarbonyl group, and an acetoxycarbonyl group.

  The sulfone group preferably has 1 to 10 carbon atoms in total, and examples thereof include a methylsulfonyl group, a benzenesulfonyl group, an ethylsulfonyl group, and an n-propylsulfonyl group.

  As the sulfonic acid ester group, those having 1 to 10 carbon atoms are preferable, and examples thereof include methoxysulfonyl, ethoxysulfonyl, propoxysulfonyl, butoxysulfonyl and the like.

  The sulfamoyl group may have a substituent and is preferably one having a total carbon number of 0 to 10, and includes a sulfamoyl group, a methylsulfamoyl group, an ethylsulfamoyl group, an n-propylsulfamoyl group, an iso -Propyl sulfamoyl group etc. are mentioned.

  As the sulfonamide group, those having 1 to 10 carbon atoms are preferable, and examples thereof include a methylsulfonamide group, an ethylsulfonamide group, and an n-propylsulfonamide group.

  The carbamoyl group may have a substituent and is preferably a group having 1 to 10 carbon atoms in total, such as carbamoyl group, methylcarbamoyl group, ethylcarbamoyl group, n-propylcarbamoyl group, iso-propylcarbamoyl group and the like. Can be mentioned.

  As the amino group, those having a substituent are preferable, and as the substituted amino group, a dialkylamino group is particularly preferable. In this case, the alkyl part of the dialkylamino group preferably has 1 to 12 carbon atoms, and may be linear or branched.

  The amide group preferably has 2 to 10 carbon atoms in total, and examples thereof include an acetamide group, a propionylamide group, a butyrylamide group, and a benzamide group.

  The alkylthio group preferably has 1 to 4 carbon atoms in total, and examples thereof include a methylthio group, an ethylthio group, an n-propylthio group, and an iso-propylthio group.

  As the alkylazomethine group, those having 2 to 5 carbon atoms are preferable, and examples thereof include a methylazomethine group, an ethylazomethine group, and an n-propylazomethine group.

Y ¹ and Y ² each have one or more active hydrogens and are not particularly limited as long as they are functional groups that may have a substituent. Examples of the functional group having one or more active hydrogens include a hydroxyl group (—OH), a thiol group (—SH), an amino group (—NH ₂ ), a carboxy group (—COOH), an amide group (—CONH ₂ ), and a sulfonamide. like group _{(-SO 2} NH 2) or a sulfo group _(-SO 3 H). Examples of the substituent include an alkyl group, an aryl group, an acyl group, an alkoxy group, a halogen group, a hydroxy group, a carboxyl group, a carboxylate group, a sulfone group, a sulfamoyl group, a sulfonamido group, a carbamoyl group, an amido group, Examples thereof include an amino group, an alkenyl group, a cyano group, a nitro group, a mercapto group, a thiocyano group, an alkylthio group, an alkylazomethine group, and an aralkyl group. Among these, an alkyl group, a sulfone group (—SO ₂ —R; R represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group), an acyl group (—CO—R; R represents a substituted or unsubstituted group, An unsubstituted alkyl group or a substituted or unsubstituted aryl group) is preferred. When R of the sulfone group and the acyl group is an alkyl group, the alkyl group preferably has 1 to 6 carbon atoms.

  By including such a chelate compound comprising an azo compound and a metal in the optical recording material together with the styryl dye described above, excellent light resistance can be obtained when an optical recording medium is constituted.

  Among the azo compounds (2) having the above-described configuration, the azo compound (2) is composed of the following general formulas (4-1) to (4-6) from the viewpoint of obtaining better light resistance. It is more preferable that it is one selected from the group.

Here, in formulas (4-1) and (4-2), Y ³ represents a residue obtained by removing two active hydrogen atoms from a functional group having two or more active hydrogen atoms. As the functional group having two or more active hydrogen atoms, an amino group (—NH ₂ ), an amide group (—CONH ₂ ) and a sulfonamide group (—SO ₂ NH ₂ ) are preferable, and an amino group is particularly preferable. Therefore, as Y ³ , —NH—, —CONH—, and —SO ₂ NH— are preferable, and —NH— is particularly preferable.

In formula (4-1), Y ⁴ represents a residue obtained by removing one active hydrogen atom from a functional group having one or more active hydrogen atoms. Examples of the functional group having one or more active hydrogen atoms include a hydroxyl group (—OH), a thiol group (—SH), an amino group (—NH ₂ ), a carboxy group (—COOH), an amide group (—CONH ₂ ), and a sulfone. Amide groups (—SO ₂ NH ₂ ) and sulfo groups (—SO ₃ H) are preferred, and hydroxyl groups are particularly preferred. Therefore, Y ⁴ is preferably —O—, —S—, —NH—, —COO—, —CONH—, —SO ₂ NH— or —SO ₃ —, and particularly preferably —O—.

In formulas (4-1) and (4-2), Y ⁵ represents a substituent, an alkyl group, a sulfone group (—SO ₂ —R; R represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. Group) and an acyl group (—CO—R; R represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group). When R of the sulfone group and the acyl group is an alkyl group, the alkyl group preferably has 1 to 6 carbon atoms.

In formulas (4-1) and (4-2), X ⁴ and X ⁵ may be the same or different, and are each an alkyl group, aryl group, acyl group, alkoxy group, alkenyl group, halogen atom, or hydroxy group. Represents a monovalent group selected from a carboxyl group, a carboxylate group, a sulfone group, a sulfonate group, a sulfamoyl group, a sulfonamido group, a carbamoyl group, an amide group, an amino group, and a nitro group. j and k may be the same or different and each represents an integer of 0 to 4. When X ⁴ or the X ⁵ in two or more adjacent carbon atoms of the benzene ring is bonded, X ⁴ s or X ⁵ together may form a ring. It may also have respective two ^{Y 3} and two ^{Y 5} in the formula (4-2) can be the same or different.

Here, in formulas (4-3), (4-4), and (4-5), X ⁶ and X ⁷ each independently have one or more active hydrogen atoms and have a substituent. R ⁸ and R ⁹ each independently represents a hydrogen atom, an alkyl group or an aryl group, R ⁸ and R ⁹ may be linked to form a ring, R ¹⁰ , R ¹¹ and R ¹² each independently represents a hydrogen atom, an alkyl group, a halogen atom, a hydroxy group, a carboxyl group, a carboxylic acid ester group, a sulfone group, a sulfonic acid ester group, a sulfamoyl group, a sulfonamide group, a carbamoyl group, an amide group, an amino group, It represents a monovalent group selected from an aryl group, an acyl group, an alkoxy group and an alkenyl group, R ¹⁰ and R ¹¹ may be linked to form a ring, R ⁸ and R ¹¹ , and R ⁹ and R ^12. Respectively May be sintered to form a ring, but do As a combination of R ⁸ and R ^9, is one a hydrogen atom or an alkyl group of R ⁸ and R ^9, the other is an aryl group, R ⁸ And R ⁹ form a ring, or R ⁸ and R ¹¹ and one or both of R ⁹ and R ¹² form a ring. R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are each independently a hydrogen atom, halogen atom, hydroxy group, carboxyl group, sulfone group, aryl group, acyl group, sulfonamide group, amide group, cyano group, nitro group, mercapto A monovalent group selected from a group, a thiocyano group, an amino group, an alkylthio group, an alkylazomethine group, a carboxylic acid ester group, a carbamoyl group, a sulfonic acid ester group, a sulfamoyl group, an alkyl group, an alkoxy group, an aralkyl group, and an alkenyl group. R ¹³ and R ¹⁴ , R ¹⁴ and R ¹⁵ , and R ¹⁵ and R ¹⁶ may be connected to each other to form a ring.

Here, in the formula (4-6), X ⁸ and X ⁹ each represent a functional group which has one or more chemical hydrogen atoms and may have a substituent, and R ¹⁸ , R ¹⁹ , R ²⁰ , R ²¹ , R ²² and R ²³ are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxy group, an amino group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, Substituted or unsubstituted heterocyclic residue, substituted or unsubstituted alkylcarbonyl group, substituted or unsubstituted arylcarbonyl group, substituted or unsubstituted alkyloxycarbonyl group, substituted or unsubstituted aryloxycarbonyl group, substituted or An unsubstituted alkylsulfonyl group, a substituted or unsubstituted arylsulfonyl group, a substituted or unsubstituted alkylthiooxy group, Or an unsubstituted arylthiooxy group, a substituted or unsubstituted alkyloxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted alkylamino group, a substituted or unsubstituted arylamino group, a substituted or unsubstituted Represents an alkylcarbonylamino group, a substituted or unsubstituted arylcarbonylamino group, a substituted or unsubstituted alkylcarbamoyl group, a substituted or unsubstituted arylcarbamoyl group, a substituted or unsubstituted alkenyl group, and R ¹⁸ and R ¹⁹ , R ¹⁹ and R ²⁰ , or R ²⁰ and R ²¹ may be linked to form a ring.

  The chelate compound in the present invention is a metal chelate compound formed by coordination of the above-mentioned azo compound to a metal, and is also called an azo dye or an azo dye.

  Examples of the metal constituting the chelate compound (central metal) include titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, silver, cadmium, indium, tin, Antimony, tungsten, rhenium, osmium, iridium, platinum, gold and the like can be mentioned. Among these, cobalt and nickel are preferable.

  In the above-described chelate compound according to the present invention, for example, a tridentate in which two active hydrogen atoms are eliminated from the azo compound (2) represented by the general formula (4-1) or (4-2) A coordination bond between the ligand and the metal may be formed. For example, when the metal is cobalt (Co), as shown in the following formula (5-1) or (5-2), two tridentate ligands coordinate with each cobalt atom to form a chelate compound. It is formed. These chelate compounds can be obtained by synthesis according to known methods (see, for example, Furukawa, Anal. Chim. Acta., 140, p. 289, 1982).

Z ⁺ in the above general formulas (5-1) and (5-2) represents a counter cation. As the counter cation, alkali metal ions such as Na ⁺ , Li ⁺ and K ⁺ , ammonium ions, and the like are preferably used. Further, salt formation may be performed using the above-described styryl dye as a counter cation. By such integration, a salt-forming dye excellent in optical characteristics and light resistance can be obtained.

Furthermore, as counter anions of styryl dyes, specifically, halide ions (Cl ⁻ , Br ⁻ , I ⁻ etc.), ClO ₄ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , VO ₃ ⁻ , VO ₄ ³⁻ , WO ₄ ²⁻ , CH ₃ SO ₃ ⁻ , CF ₃ COO ⁻ , CH ₃ COO ⁻ , HSO ₄ ⁻ , CF ₃ SO ₃ ⁻ , p-toluenesulfonate ion (PTS ⁻ ), p-methyl trifluoride phenylsulfonate An ion (PFS ⁻ ) and the like. Among these, ClO ₄ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ^{− and the} like are preferable.

  When the styryl dye and the chelate compound according to the present invention are contained in the recording layer of the optical recording medium, the salt-forming dye may be present alone or another dye compound may be used in combination.

  In the optical recording material of the present invention, when the chelate compound is contained together with the styryl dye, the content of the styryl dye is 20 to 80 mol% based on the total amount of the styryl dye and the chelate compound. preferable. When the content ratio is less than 20 mol%, the jitter characteristics tend to deteriorate as compared with the case where the content ratio is within the above range. When the content ratio exceeds 80 mol%, the content ratio is within the above range. Compared to the case, the light resistance tends to deteriorate.

  The optical recording material of the present invention may further contain a dye compound other than the styryl dye and the chelate compound. Examples of such dye compounds include cyanine dyes.

(Optical recording medium)
FIG. 1 is a partial sectional view showing a preferred embodiment of an optical recording disk according to the optical recording medium of the present invention. An optical recording disk 1 shown in FIG. 1 is a write-once type optical recording compact disk corresponding to the DVD standard, and is capable of recording / reproducing with light having a short wavelength of 635 to 680 nm.

  As shown in FIG. 1, the optical recording disk 10 is obtained by bonding two optical recording disks with an adhesive so that their protective layers face each other. That is, the optical recording disk 10 has a substrate 12, a recording layer 13, a reflective layer 14, a protective layer 15, an adhesive layer 50, a protective layer 25, a reflective layer 24, a recording layer 23, and a substrate 22 as viewed from one side. It has a laminated structure in this order.

  The substrate 12 has a disk shape with a diameter of about 64-200 mm and a thickness of about 0.6 mm. In order to enable recording and reproduction from the back surface side (the side opposite to the recording layer 13) of the substrate 12, the substrate 12 is preferably substantially transparent to recording light and reproduction light, and more specifically. The transmittance of the substrate 12 with respect to the recording light and the reproduction light is preferably 88% or more. The material of the substrate 12 is preferably a resin or glass that satisfies the above-mentioned conditions regarding transmittance, and among them, a thermoplastic resin such as polycarbonate resin, acrylic resin, amorphous polyethylene, TPX, and polystyrene resin is particularly preferable.

  Grooves 123 and 223 are formed on the recording layer 13 formation surface of the substrate 12 and the recording layer 24 formation surface of the substrate 23, respectively. The grooves 123 and 223 are preferably spiral continuous grooves, have a depth of 60 to 200 nm, a width of 0.2 to 0.5 μm, and a groove pitch of 0.6 to 1.0 μm. Preferably there is. By configuring these grooves as described above, a good tracking signal can be obtained without reducing the reflection level of the grooves. The groove 123 can be formed at the same time when the substrate 12 is formed by injection molding or the like using the above resin. However, after the substrate 12 is manufactured, a resin layer having the groove 123 is formed by the 2P method or the like, and the substrate 12 and the resin are formed. It is good also as a composite substrate with a layer. The recording layers 13 and 23 each have a thickness of 50 to 200 nm, and the complex refractive index with respect to the recording light is preferably n = 1.8 to 2.6 and k = 0.02 to 0.20.

  The recording layer 13 is formed including the styryl dye according to the present invention, and preferably further contains the above-described chelate compound. Moreover, you may further contain other pigment | dyes other than these.

  The recording layer 13 can be formed by applying a coating liquid containing the styryl dye according to the present invention on the substrate 12 and drying the coating film as necessary. Specific examples of the solvent for the coating liquid include alcohol solvents (including alkoxy alcohols such as keto alcohols and ethylene glycol monoalkyl ethers), aliphatic hydrocarbon solvents, ketone solvents, and ester solvents. , Ether solvents, aromatic solvents, alkyl halide solvents and the like. Among them, alcohol solvents and aliphatic hydrocarbon solvents are preferable.

  As the alcohol solvent, an alkoxy alcohol system, a keto alcohol system, or the like is preferable. In the alkoxy alcohol solvent, the alkoxy moiety preferably has 1 to 4 carbon atoms, the alcohol moiety preferably has 1 to 5 carbon atoms, more preferably 2 to 5 carbon atoms, and the total number of carbon atoms. It is preferable that it is 3-7. Specifically, ethylene glycol monoalkyl ether (cellosolve) such as ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (also referred to as ethyl cellosolve, ethoxyethanol), butyl cellosolve, 2-isopropoxy-1-ethanol, etc. And 1-methoxy-2-propanol, 1-methoxy-2-butanol, 3-methoxy-1-butanol, 4-methoxy-1-butanol, 1-ethoxy-2-propanol and the like. Examples of keto alcohols include diacetone alcohol. Furthermore, fluorinated alcohols such as 2,2,3,3-tetrafluoropropanol can also be used.

  As the aliphatic hydrocarbon solvent, n-hexane, cyclohexane, methylcyclohexane, ethylcyclohexane, cyclooctane, dimethylcyclohexane, n-octane, iso-propylcyclohexane, t-butylcyclohexane and the like are preferable. Cyclohexane and the like are preferable.

  Moreover, cyclohexanone etc. are mentioned as a ketone type | system | group.

  In the present invention, an alkoxy alcohol system such as an ethylene glycol monoalkyl ether system is particularly preferable, and ethylene glycol monoethyl ether, 1-methoxy-2-propanol, 1-methoxy-2-butanol and the like are particularly preferable. A solvent may be used individually by 1 type, or 2 or more types of mixed solvents may be sufficient as it. For example, a mixed solvent of ethylene glycol monoethyl ether and 1-methoxy-2-butanol is preferably used.

  The coating liquid may contain a binder, a dispersant, a stabilizer, and the like as appropriate in addition to the styryl dye and the chelate compound according to the present invention. The content of the styryl dye in the coating solution is preferably 0.5 to 3.0% by mass.

  As a coating method of the coating liquid, a spin coating method, a gravure coating method, a spray coating method, a dip coating method, or the like can be applied, and among these, the spin coating method is preferable.

  The thickness of the recording layer 13 thus formed is preferably 30 to 300 nm in terms of a dry film thickness. Outside this range, the reflectivity decreases and it becomes difficult to perform reproduction in accordance with the DVD standard.

  Further, the extinction coefficient (imaginary part k of the complex refractive index) of the recording layer 13 with respect to the recording light and the reproduction light is preferably 0 to 0.20. When the extinction coefficient exceeds 0.20, sufficient reflectance tends not to be obtained. The refractive index of the recording layer 13 (real part n of the complex refractive index) is preferably 1.8 or more. When the refractive index is less than 1.8, the degree of signal modulation tends to be small. The upper limit of the refractive index is not particularly limited, but is usually about 2.6 for the convenience of organic dye synthesis.

  The extinction coefficient and refractive index of the recording layer 13 can be obtained according to the following procedure. First, a recording sample is provided on a predetermined transparent substrate at a thickness of about 40 to 100 nm to prepare a measurement sample, and then the reflectance of the measurement sample through the substrate or the reflectance from the recording layer side is measured. Desired. In this case, the reflectance is measured by specular reflection (about 5 °) using the wavelength of the recording / reproducing light. Further, the transmittance of the sample is measured. From these measured values, the extinction coefficient and the refractive index can be calculated according to the method described in, for example, Kyoritsu Zensho “Optics”, Kozo Ishiguro, pages 168 to 178.

  On the recording layer 13, the reflective layer 14 is provided in close contact with the recording layer 13. The reflective layer 14 can be formed by performing vapor deposition, sputtering, or the like using a highly reflective metal or alloy. Examples of such metals and alloys include gold (Au), copper (Cu), aluminum (Al), silver (Ag), and AgCu. The thickness of the reflective layer 14 formed in this way is preferably 50 to 120 nm.

  A protective layer 15 is provided in close contact with the reflective layer 14 on the reflective layer 14. The protective layer 15 may be a layer or a sheet. For example, the protective layer 15 is formed by applying a coating liquid containing a material such as an ultraviolet curable resin on the reflective layer 14 and drying the coating film as necessary. Is possible. In such coating, spin coating, gravure coating, spray coating, dip coating, or the like can be applied. The thickness of the protective layer 15 thus formed is preferably 0.5 to 100 μm.

  Further, as shown in FIG. 2, a dummy substrate 16 may be provided on the protective layer 15 so as to be in close contact with the protective layer 15. The dummy substrate 16 can be made of the same material and thickness as the substrate 12.

  When recording or additional recording is performed on the optical recording disk 10 having the above-described configuration, recording light having a predetermined wavelength is irradiated in a pulse form from the back surface of the substrate 12 to change the light reflectance of the irradiated portion. According to the optical recording disk 10 provided with the recording layer 13 containing a styryl dye according to the present invention, for example, high-speed recording at 4 × speed or more is possible, and jitter at that time can be sufficiently reduced.

  In the above embodiment, an optical recording disk having one recording layer 13 has been described. However, a plurality of recording layers may be provided, and each layer may contain an organic dye that reacts when irradiated with light of different wavelengths. Thereby, information can be recorded / reproduced by a plurality of recording / reproducing lights having different wavelengths. In this case, a reflective film that is translucent to recording / reproducing light of each wavelength may be provided on each recording layer.

  As a material of the adhesive layer 50, a thermosetting resin or the like is preferably used. The thickness of the adhesive layer 50 is about 10 to 200 μm.

  As mentioned above, although preferred embodiment of DVD-R of this invention was described, this invention is not limited to the said embodiment. For example, the optical recording disc is not limited to the configuration of the optical recording disc 10 described above, and a configuration in which the protective layer is also provided with the function of an adhesive layer is also possible.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

Example 1
A polycarbonate resin substrate having a diameter of 120 mm and a thickness of 0.6 mm having pregrooves (groove depth 140 nm, width 0.33 μm, groove pitch 0.74 μm) on one side was prepared. On the other hand, the hexafluorophosphorus salt of the styryl dye represented by the above formula (3-1) was synthesized by a general styryl dye synthesis method. The chelate compound of the obtained hexafluorophosphorus salt of the styryl dye represented by the above formula (3-1) and the azo compound represented by the following formula (6-1) has a content of 1.0. A recording layer-forming coating solution was prepared by dissolving in 2,2,3,3-tetrafluoropropanol so as to have a mass%.

  The obtained coating solution was applied on the surface of the polycarbonate resin substrate on which the pregroove was formed, and dried to form a recording layer (thickness: 100 nm). Next, an Ag reflection layer (thickness 150 nm) is formed on the recording layer by sputtering, and a transparent protective layer (thickness 5 μm) made of an ultraviolet curing acrylic resin is further formed on the Ag reflection layer. Thus, a laminated structure was obtained. Two such laminated structures were produced and bonded with an adhesive so that their protective layers were on the inside, and an optical recording disk having the structure shown in FIG. 2 was obtained.

(Example 2)
Instead of the chelate compound of the hexafluorophosphorus salt of the styryl dye represented by the above formula (3-1) and the azo compound represented by the above formula (6-1), the above formula (3-2) The optical recording of Example 2 was performed in the same manner as in Example 1 except that a chelate compound of a hexafluorophosphorus salt of a styryl dye represented by the following formula (6-2) was used. A disk was made. The styryl dye hexafluoride salt represented by the above formula (3-2) was synthesized by a general styryl dye synthesis method.

(Examples 3 to 6)
Instead of the chelate compound of the hexafluorophosphorus salt of the styryl dye represented by the above formula (3-1) and the azo compound represented by the above formula (6-1), the above formula (3-3) A hexafluorophosphorus salt of a styryl dye represented by the formula, a hexafluorophosphorus salt of a styryl dye represented by the formula (3-4), and six styryl dyes represented by the formula (3-5) The optical recording disks of Examples 3 to 6 were the same as Example 1 except that only the phosphorous fluoride salt and the hexafluorophosphorus salt of the styryl dye represented by the above formula (3-6) were used. Was made. The above styryl dye hexafluorophosphates were synthesized by a general method of synthesizing styryl dyes.

(Examples 7 to 8)
Instead of the chelate compound of the hexafluorophosphorus salt of the styryl dye represented by the above formula (3-1) and the azo compound represented by the above formula (6-1), the above formula (3-7) A chelate compound of a styryl-based dye hexafluorophosphorus salt represented by the above formula (6-2) and a styryl dye represented by the above formula (3-8) Optical recording disks of Examples 7 and 8 were produced in the same manner as in Example 1 except that a chelate compound of a salt and an azo compound represented by the following formula (6-3) was used. The above styryl dye hexafluorophosphates were synthesized by a general method of synthesizing styryl dyes.

(Examples 9 to 12)
Instead of the chelate compound of the hexafluorophosphorus salt of the styryl dye represented by the above formula (3-1) and the azo compound represented by the above formula (6-1), the above formula (3-9) A hexafluorophosphorous salt of a styryl dye represented by the formula, a phosphorous hexafluoride salt of a styryl dye represented by the formula (3-10), and six of a styryl dye represented by the formula (3-11). The optical recording disks of Examples 9 to 12 were the same as Example 1 except that only the phosphorous fluoride salt and the hexafluorophosphorus salt of the styryl dye represented by the above formula (3-12) were used. Was made. The above styryl dye hexafluorophosphates were synthesized by a general method of synthesizing styryl dyes.

(Comparative Example 1)
Instead of the chelate compound of the hexafluorophosphorus salt of the styryl dye represented by the above formula (3-1) and the azo compound represented by the above formula (6-1), it is represented by the following formula (7). An optical recording disk of Comparative Example 1 was produced in the same manner as in Example 1 except that the styryl dye hexafluorophosphate salt was used. The styryl dye hexafluoride salt represented by the following formula (7) was synthesized by a general styryl dye synthesis method.

[Evaluation of recording / playback characteristics]
Signals were recorded on the optical recording disks of Examples 1 to 12 and Comparative Example 1 at a linear velocity of 14.0 m / sec (corresponding to a quadruple velocity) using laser light having a wavelength of 655 nm. Next, jitter was measured when reproduction was performed at a linear velocity of 3.5 m / sec using laser light having a wavelength of 655 nm. At this time, the lens aperture NA was set to 0.60. Further, the obtained optical recording disk was irradiated (light-exposed) for 80 hours with a 50,000-lux xenon lamp (Xenon Fade Meter, manufactured by Shimadzu Corporation), and the optical recording disk after irradiation was also the same as described above. Jitter was measured to evaluate its light resistance. These results are shown in Table 1.

  As is apparent from the results shown in Table 1, according to Examples 1 to 12, compared to Comparative Example 1, the jitter at the time of high-speed recording at 4 × speed is suppressed, and the light resistance is excellent. confirmed. Therefore, according to the present invention, an optical recording material for an optical recording medium capable of high-speed recording, capable of sufficiently reducing jitter at that time, and capable of obtaining excellent light resistance, and optical It has been confirmed that a recording medium is provided.

1 is a partial cross-sectional view showing a preferred embodiment of an optical recording disk according to an optical recording medium of the present invention. It is a fragmentary sectional view showing other suitable one Embodiment of the optical recording disc concerning the optical recording medium of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Optical recording disk, 12, 22 ... Substrate, 13, 23 ... Recording layer, 14, 24 ... Reflective layer, 15, 25 ... Protective layer, 16 ... Dummy substrate, 123, 223 ... Groove, 50 ... Adhesive layer.

Claims (3)

An optical recording material used for an optical recording medium capable of recording information by light irradiation,
An optical recording material comprising a styryl dye represented by the following general formula (1).

[In formula (1), R ¹ represents an alkyl group or an aryl group having 1 to 6 carbon atoms, R ² represents a benzyl group which may have an alkyl group or a substituent having 1 to 2 carbon atoms, X ¹ and X ² each independently represent a halogen atom, an alkyl group having 1 to 2 carbon atoms, or an oxyalkyl group having 1 to 2 carbon atoms, and X ³ represents an alkyl group having 1 to 4 carbon atoms or an alkylamino group. , P, q and r each independently represents an integer of 0 to 4. When p is 2 or more, a plurality of X ¹ may be the same or different, and X ¹ may be linked together to form a ring. When q is 2 or more, a plurality of X ² may be the same or different, and X ² may be linked to form a ring. Furthermore, when r is 2 or more, a plurality of X ³ may be the same or different, and X ³ may be linked to form a ring. ] 2. The optical recording material according to claim 1, further comprising a chelate compound obtained by coordinating a metal with an azo compound represented by the following general formula (2).

[In the formula (2), B ¹ and B ² each independently represent an atomic group constituting an aromatic ring, Y ¹ and Y ² each independently have one or more active hydrogen atoms, The functional group which may have is shown. ] An optical recording medium capable of recording information by light irradiation,
An optical recording medium comprising a recording layer containing the optical recording material according to claim 1.

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