JP2976121B2 - Optical information recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention has a recording layer for recording information by inducing a state change by irradiation with a laser beam, detecting a difference in optical properties, and reading the information. The present invention relates to an optical information recording medium.

(Prior Art) A so-called dye-based optical disk is known, in which an organic dye is carried on a substrate, and information is recorded by utilizing the fact that the organic dye is altered by irradiation with laser light. It is said that a cyanine dye is particularly preferable as the dye. Among the cyanine dyes, cyanine dyes containing an indolenine ring or a benzindolenin ring as an auxiliary chromophore have been used as preferred. In recent years, in order to be able to read information using a compact disc player, by providing a metal reflective layer on the above-mentioned optical information recording medium, a high light intensity of about 70% with respect to light having a wavelength of 780 nm has been achieved. Attempts to provide reflectivity have been successful. In addition, if the amount of the dye that should absorb light is simply reduced so that the reflectance is increased, the recording characteristics deteriorate. However, when not only reducing the amount of light-absorbing dye carried, but also using a compound that has an absorption maximum wavelength on the shorter wavelength side than the light-absorbing dye, the cause is not clear, but high reflectivity without deterioration in recording characteristics It is known that conversion can be achieved. When such dyes are mixed and used, depending on the structure of the dyes to be mixed, the storage stability under high temperature and high humidity and the stability upon light irradiation may be reduced, and improvement has been required.

(Problems to be Solved by the Invention) The first object of the present invention is to provide an optical information recording medium which is excellent in storage stability and light resistance under high temperature and high humidity and has a high reflectance enough to be read by a CD player. It is to be.

(Means for Solving the Problems) The object of the present invention is to provide the following general formula (I) or (I)
An optical information recording medium for recording or reproducing information by utilizing a state change caused by irradiation with a laser beam, characterized by carrying at least one of the compounds represented by I). Was achieved.

[Wherein T represents an atomic group for completing a benzene ring which may have a substituent, and R ¹ to R ³ represent alkyl, aralkyl, phenyl and allyl which may have a substituent. , L ¹ represents a trivalent linking group formed by linking ¹ , 3, 5 or 7 optionally substituted methine groups with a conjugated double bond, and Z represents a 5- or 6-membered ring X represents an anion, and p represents
L represents a tetravalent linking group formed by linking ² , 4 or 6 methine groups to complete a conjugated double bond, and Q represents a 5- or 6-membered ring. Represents an atomic group for forming In the general formulas (I) and (II), preferred examples of the substituent on the benzene ring completed by the group of atoms represented by T include a halogen atom (F, C, Br, I) and the number of carbon atoms. 1 to 8 alkyl groups, 1 to 8 carbon atoms
An alkoxy group having 6 to 10 carbon atoms, a substituted or unsubstituted phenoxy group, an amino group, a 1 or 2 substituted amino group, an alkylthio group having 1 to 8 carbon atoms, a substituted or unsubstituted having 6 to 10 carbon atoms And these groups may be connected to each other to form a ring.

Among the atoms represented by T, particularly preferred are atoms for forming an unsubstituted benzene ring.

Preferred as the groups represented by R ¹ and R ² are an alkyl group having 1 to 8 carbon atoms, a benzyl group having carbon atoms,
Phenyl, phenylpropyl, phenyl, and allyl groups, and these groups further include a halogen atom (F, C
, Br, I), an alkoxy group or an alkylthio group. Particularly preferred as the groups represented by R ¹ and R ² may be substituted with a halogen atom having 3 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkylthio group having 1 to 4 carbon atoms. It is an alkyl group.

Preferred as a 5- or 6-membered ring completed by the group of atoms represented by Z are so-called basic nuclei, for example, a pyridine ring, a quinoline ring, an oxazole ring, a benzoxazole ring, a thiazole ring,
Examples thereof include a benzothiazole ring, an imidazole ring, a benzimidazole ring, an indolenine ring, and a benzindolenine ring, and a particularly preferable one is a ring represented by the following formula.

[Wherein T represents a group having the same meaning as T in the general formula (I), and R ₃ ,
R ₄ represents a group having the same meaning as R ₁ and R _{2 in} formula (I). Preferred as the linking group represented by L ¹ are 1,
3, 5, and 7 unsubstituted methine groups, methine groups substituted with an alkyl group having 1 to 8 carbon atoms, methine groups substituted with a benzyl group, methine groups substituted with a phenyl group, halogen atoms And a methine group substituted with an unsubstituted or disubstituted amino group, and the substituents on the methine group may be connected to each other to form a ring. Among the linking groups represented by L, particularly preferred are those composed of only an unsubstituted methine group and those in which only the central methine group is substituted with a methyl, ethyl, benzyl or phenyl group.

Preferred as the anion represented by X are a halide ion, a perhalate ion, a sulfonate ion,
Optionally substituted phosphate ions, tetrasubstituted boronate ions, hexasubstituted phosphate ions, hexasubstituted antimonate ions, heavy metal complex ions such as bis (benzene-1,2-dithiolato) nickelate ion, Particularly preferred are CO ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ⁻ , p-toluenesulfonate, BF ₄ ⁻ and I ⁻ .

Preferred as the linking group represented by L ² are 2, 4
Or 6 unsubstituted methine groups, having 1 to 8 carbon atoms
A methine group substituted with an alkyl group, a methine group substituted with a benzyl group, a methine group substituted with a phenyl group, and a methine group substituted with a halogen atom. The two may be connected to each other to form a ring. Particularly preferred as the linking group represented by L ² are those composed of 2, 4 or 6 unsubstituted methine groups.

Preferred as a group of atoms for completing the 5- or 6-membered ring represented by Q is a group of atoms for completing a so-called acidic nucleus. Examples of the ring completed thereby include pyridone, 1 And heterocycles such as 3,3-substituted-2-pyrazolin-5-one, 3,5-dioxopyrazole, barbituric acid, hydantoin, and rhodanin. Particularly preferred among the 5- or 6-membered rings represented by Q are 1,3-
It is a substituted-2-pyrazolin-5-one or rhodanin ring.

The group represented by R ₃ is a group selected from the groups having the same meaning as R _1, and p is preferably 1.

Specific examples of the compounds represented by formulas (I), (II) and (III) are shown below, but the scope of the present invention is not limited only to these.

The synthesis of the compound represented by the general formula (I) or (II) of the present invention is described in Ukr.Khim.Zh., published in Chemical Abstracts, Vol. 71, 22892k, 35, 288-29 (1969).
It can be synthesized as described on page 1. Hereinafter, the synthesis method will be specifically described with reference to synthesis examples.

Synthesis Example 1 Synthesis of Compound I-8 1,4-Diisobutyl-2-methyl 4,9-
0.23 g of dihydro-4,9-dioxonaphtho [2,3-d] imidazolium 4-methylbenzenesulfonate and 1 ml of ethyl orthoformate were added, and the mixture was heated under reflux for 6.5 hours. The solvent was distilled off under reduced pressure, and after adding 3 ml of methanol, 0.3 g of tetrabutylammonium perchlorate dissolved in 3 ml of methanol was added. The precipitated crystals were collected and washed with methanol to obtain blue-green crystals of compound I-8.

Yield 86 mg λλ ^methanol _max ▼ = 502 nm.

Synthesis Example 2 Synthesis of Compound I-32 1,4-Diisobutyl-2-methyl 4,9-dihydro-4,9-dioxonaphtho [2, N-dimethylformamide
3-d) Imidazolium 4-methylbenzenesulfonate 0.9 g and 1,5-diaza-1,5-diphenyl-1,3-pentadiene 180 mg were added and dissolved, and then 0.18 ml of acetic anhydride was added.
1,8-diazabicyclo [5.4.0] -7-undecene 0.27 ml
And stirred at room temperature for 2 hours. The reaction solution was poured into 150 ml of water, and the resulting solid was collected and washed with water. This solid was dissolved in methanol (20 ml), and tetrabutylammonium perchlorate (1 g) dissolved in methanol (2 ml) was added. The precipitated crystals were collected and washed with methanol to obtain green crystals of compound I-32.

Yield 210 mg, melting point 225-226 ° C (decomposition), λ ^methanol _max ▼ = 600 nm.

Synthesis Example 3 Synthesis of Compound I-33 1,3-Dibutyl-2 was added to 30 ml of N, N-dimethylformamide.
-Methyl 4,9-dihydro-4,9-dioxonaphtho [2,3-
d] imidazolium 4-methylbenzenesulfonate 5 g
And 1,5-diaza-1,5-diphenyl-1,3-pentadiene
1.1 g, acetic anhydride 1 ml, 1,8-diazabicyclo [5.4.0]-
2.2 ml of 7-undecene was added and stirred at room temperature for 2 hours.

The reaction mixture was poured into a solution prepared by dissolving 5 g of tetrabutylammonium perchlorate in 150 ml of methanol. The resulting crystals were collected and washed with methanol to obtain 0.5 g of yellowish green metallic luster crystals of Compound I-33. Melting point 215-2
16 ° C (decomposition).

▲ λ ^methanol _max ▼ = 596 nm.

In the recording medium of the present invention, the compound represented by the general formula (I) or (II)
May be used alone or in combination with other compounds. Examples of dyes used in combination include cyanine dyes, phthalocyanine dyes, pyrylium / thiopyrylium dyes, azurenium dyes, squarylium dyes, metal complex salt dyes such as Ni and Cr, and naphthoquinone dyes.
Examples include anthraquinone dyes, indophenol dyes, indoaniline dyes, triphenylmethane dyes, triallylmethane dyes, aminium / diimmonium dyes, and nitroso compounds.

Further, in order to improve the light resistance, it is preferable to use various dyes known as a so-called singlet oxygen quencher, for example, a compound represented by the following general formula (III) or (IV).

(However, [Cat] ⁺ represents a nonmetallic cation such as tetraalkylammonium, M represents a transition metal atom such as Ni, and Z and Z ′ represent an optionally substituted benzene ring, 2-thioxo-1 Represents an atomic group for completing a 5- or 6-membered aromatic or heterocyclic ring such as a, 3-dithiol ring) [Wherein R represents an alkyl group which may have a substituent, and Q represents the same anion as that represented by X in the general formula (I)]. The above general formula (III) or (IV) Specific examples of the quencher represented by are PA-1006 (Mitsui Toatsu Fain Co., Ltd.), IRG-023 (Nippon Kayaku Co., Ltd.) and the like.

The recording layer is formed by dissolving the dye, and, if desired, the quencher and the binder in a solvent to prepare a coating solution, and then applying the coating solution to the substrate surface to form a coating film and then drying. Can be performed.

Examples of the solvent for preparing the dye layer coating solution of the present invention include: esters such as ethyl acetate, butyl acetate, and cellosolve acetate; ketones such as methyl ethyl ketone, cyclohexanone, and methyl isobutyl ketone;
Chlorinated hydrocarbons such as dichloroethane and chloroform;
Amides such as dimethylformamide; hydrocarbons such as cyclohexane; tetrahydrofuran, ethyl ether,
Ethers such as dioxane; alcohols such as ethanol, n-propanol, isopropanol and n-butanol; and fluorine-based solvents such as 2,2,3,3-tetrafluoropropanol.

Antioxidants, UV absorbers, plasticizers,
Various additives such as a lubricant may be added according to the purpose.

When a binder is used, examples of the binder include natural organic high molecular substances such as gelatin, cellulose derivatives, dextran, rosin, and rubber; hydrocarbon resins such as polyethylene, polypropylene, polystyrene, and polyisobutylene; and polyvinyl chloride. , Polyvinylidene chloride,
Vinyl resins such as polyvinyl chloride / 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 the like. Synthetic organic polymer substances such as an initial condensate of a thermosetting resin.

When a binder is used as a material for the recording layer, the ratio of the dye to the binder is generally in the range of 0.01 to 99% (weight ratio), preferably in the range of 1.0 to 95% (weight ratio). The concentration of the coating solution prepared in this way is generally 0.
01 to 10% (weight ratio), preferably 0.1 to 5%
% (Weight ratio).

The recording layer may be a single layer or a multilayer, but the layer thickness is generally
It is in the range of 200-3000 °, preferably in the range of 500-2500 °. The recording layer may be provided not only on one side of the substrate but also on both sides.

Examples of the coating method include a spray method, a spin coating method, a dipping method, a roll coating method, a blade coating method, a doctor roll method, and a screen printing method.

Further, in the information recording medium of the present invention, it is preferable to provide a reflective layer on the recording layer for the purpose of improving C / N and improving reflectivity during information reproduction.

The light-reflective substance that is the material of the reflective layer is a substance having a high reflectance to laser light, and examples thereof include Mg, Se,
Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, F
e, Co, Ni, Ru, Rh, Pd, Ir, Pt, Cu, Ag, Au, Zn, C
Examples thereof include metals such as d, Al, Ga, In, Si, Ge, Te, Pb, Po, Sn, and Bi and semimetals or stainless steel. Of these, preferred are Cr, Ni, Pt, C
u, Ag, Au, Al and stainless steel. These substances may be used alone or in combination of two or more kinds or as an alloy.

The reflection layer can be formed on the recording layer by, for example, vapor deposition, sputtering, or ion plating of the above-mentioned light reflective substance. The thickness of the reflective layer is generally in the range from 100 to 3000 °.

Further, 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 of the substrate on which the recording layer is not provided for the purpose of improving the scratch resistance and the moisture resistance.

Examples of materials used for the protective layer include SiO, SiO ₂ , M
gF _2, inorganic substances such as SnO _2, Si ₃ N _4; thermoplastic resins, thermosetting resins, and organic materials such as UV curable resin.

The protective layer can be formed, for example, by laminating a film obtained by plastic extrusion on a recording layer (or silver salt layer or reflective layer) and / or a substrate via an adhesive layer. Or vacuum deposition,
It may be provided by a method such as spattering or coating. Further, in the case of a thermoplastic resin or a thermosetting resin, they can be formed by dissolving these in an appropriate solvent to prepare a coating solution, and then applying and drying this 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 an appropriate solvent, applying the coating solution, and irradiating with UV light to cure. Various additives such as an antistatic agent, an antioxidant and a UV absorber may be added to these coating solutions according to the purpose.

 The thickness of the protective layer is generally in the range from 0.1 to 100 μm.

In the present invention, the information recording medium may be a single plate having the above-described configuration, or two substrates having the above-described configuration are arranged such that the recording layer faces inside,
By bonding using an adhesive or the like, a bonding type recording medium can also be manufactured. Alternatively, by using a substrate having the above configuration on at least one of the two disk-shaped substrates and joining the ring-shaped inner spacer and the ring-shaped outer spacer via each other, an air-square-type recording medium is formed. Can also be manufactured.

(Example) [Example 1] 1.6 g of the dye A and 0.4 g of the dye represented by the general formula (I) or (II) (the dye I-33) were mixed with 2,2,3,3-tetrafluorofluoroethylene. It was dissolved in 100 cc of propanol (structural formula: HCF ₂ CF ₂ CH ₂ OH) to prepare a dye layer coating solution.

On a disc-shaped polycarbonate substrate (outer diameter: 120 mm, inner diameter: 15 mm, thickness: 1.2 mm, tracking pitch: 1.6 μm, group width: 0.5 μm, groove depth: 900 mm) provided with a tracking guide, The coating solution was applied at a rotation speed of 1,000 rpm by a spin coating method and dried for 30 seconds to form a recording layer having a layer thickness of 1300 °.

Further DC sputtering of Au on the recording layer described above
A 1300 mm reflective layer was formed.

A UV curable resin (trade name: 3070, manufactured by Three Bond Co.) is applied as a protective layer on the reflective layer by a spin coat method at a rotation speed of 1500 rpm, and then cured by irradiating ultraviolet rays with a high-pressure mercury lamp. A protective layer having a thickness of 3 μm was formed.

Thus, an information recording medium including the substrate, the recording layer, the reflective layer, and the protective layer was manufactured.

[Example 2] In Example 1, a diimmonium compound having the following structural formula (IR
An information recording medium was manufactured in the same manner as in Example 1 except that 0.2 g of G-023 (manufactured by Nippon Kayaku Co., Ltd.) was added to prepare a dye layer coating solution.

Example 3 In Example 1, a substrate having a depth of 1600 ° was used instead of a substrate having a groove depth of 900 °, 1.6 g of dye A was changed to 1.0 g, and the compound represented by the general formula (I) or (II) was used. 0.4 g of the dye represented (the dye I-33) was changed to 1.0 g, and 0.2 g of the diimmonium compound (IRG-023, manufactured by Nippon Kayaku Co., Ltd.) was further added as a quencher to prepare a dye layer coating solution. An information recording medium was manufactured in the same manner as in Example 1 except that the thickness of the recording layer was changed from 1300 ° to 2000 °.

Example 4 An information recording medium was manufactured in the same manner as in Example 3, except that the dye B was used instead of the dye A.

[Comparative Example 1] In Example 1, 1.6 g of the dye A was changed to 2.0 g, and the dye represented by the general formula (I) or (II) (the dye I-
An information recording medium was manufactured in the same manner as in Example 1 except that the dye coating solution was prepared without using 33).

Comparative Example 2 Comparative Example 1 was conducted in the same manner as in Comparative Example 1, except that 0.4 g of the above-mentioned diimmonium compound (IRG-023, manufactured by Nippon Kayaku Co., Ltd.) was further added as a quencher to the dye coating solution. An information recording medium was manufactured in the same manner as described above.

Table 1 shows the compositions of the dye coating solutions obtained in the above Examples and Comparative Examples.

[Evaluation of Information Recording Medium] 1) Reflectivity The obtained information recording medium was irradiated with light having a wavelength of 780 nm from the substrate side using a spectrophotometer (manufactured by Hitachi, Ltd.) to reflect unrecorded portions. The rate was measured.

2) C / N The information recording medium obtained above was subjected to a constant linear velocity of 1.3 m / sec and a recording power of 780 nm using a semiconductor laser beam.
At 7.0 mW, a signal with a modulation frequency of 720 kHz (duty 33%) was recorded. Then, the recorded signal was reproduced with a reproduction power of 0.5 mW, and the C / N during the reproduction was measured using a spectrum analyzer (TR4135: manufactured by Advantest).

 Table 2 shows the measurement results.

As is evident from Table 2, the optical disks (Examples 1 to 4) having a recording layer composed of the specific two kinds of cyanine dyes of the present invention have extremely high reflectance and high C / N. The level is maintained. Therefore, when quencher was added to improve the light fastness, Examples 2 and 3 were used.
And 4, high reflectivity can be maintained.

On the other hand, an optical disk using only a dye having a benzoindolenine skeleton, which is generally known for its high reflectance (Comparative Example 1), has a low reflectance as compared with the Examples, and has a CD player. Therefore, it cannot be said that the reflectance is sufficiently satisfactory for reproducing information. For this reason, the addition of the quencher (Comparative Example 2) resulted in a reflectance lower than 70%.

Claims (2)

(57) [Claims] 1. A method according to claim 1, wherein at least one of the compounds represented by the following general formula (I) or (II) is carried on a substrate. Information recording medium for recording or reproducing information. [Wherein T represents an atomic group for completing a benzene ring which may have a substituent, and R ¹ to R ³ represent alkyl, aralkyl, phenyl and allyl which may have a substituent. , L ¹ represents a trivalent linking group formed by linking ¹ , 3, 5 or 7 optionally substituted methine groups with a conjugated double bond, and Z represents a 5- or 6-membered ring X represents an anion, and p represents
L represents a tetravalent linking group formed by linking ² , 4 or 6 methine groups to complete a conjugated double bond, and Q represents a 5- or 6-membered ring. Represents an atomic group for forming ] 2. The method according to claim 1, further comprising a light reflecting layer made of metal.
Optical information recording medium described in the item