JPH0816199B2 - Naphthoquinone methide compounds - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel naphthoquinone methide compound.

[Conventional technology]

In recent years, optical recording using a laser has been particularly developed in order to enable high-density information storage and reproduction.

An example of the optical recording is an optical disk.

Generally, in an optical disc, a thin recording layer provided on a circular substrate is irradiated with a laser beam focused to about 1 μm,
High-density information recording is performed. The recording is performed by the absorption of the irradiated laser light energy, which causes thermal deformation such as decomposition, evaporation, and dissolution in the recording layer at that location. The recorded information is reproduced by reading the difference in reflectance between the portion where the laser light is deformed and the portion where the laser light is not deformed.

Therefore, as an optical recording medium, it is necessary to efficiently absorb the energy of the laser light, so that the absorption of the laser light of the specific wavelength used for recording is large, and the information is reproduced accurately, so it is used for the reproduction. It is necessary that the reflectance with respect to the laser light of the specified wavelength is high.

Various types of optical recording media are known as this type of optical recording medium.

For example, JP-A-55-97033 discloses a substrate in which a single layer of a phthalocyanine dye is provided. However, phthalocyanine dyes have low sensitivity,
In addition, it has a problem that it has a high decomposition point and is difficult to vapor-deposit, and further has a problem that its solubility in an organic solvent is extremely low and it cannot be used for coating by application.

Further, JP-A-58-83344 discloses a phenalene dye, and JP-A-58-224793 discloses a naphthoquinone dye in a recording layer. However, such a dye has a disadvantage that it has a low reflectance, while it has an advantage that it is easily vapor-deposited. When the reflectance is low, the contrast relating to the reflectance between the portion recorded by the laser beam and the unrecorded portion is low, and it becomes difficult to reproduce the recorded information. Further, organic dyes generally have a problem of poor storage stability.

[Problems to be solved by the invention]

It is an object of the present invention to provide a naphthoquinone methide compound having high solubility in an organic solvent, coating by coating is possible, high reflectance, good contrast, and excellent storage stability. Is.

[Means for solving problems]

The gist of the present invention is a naphthoquinone methide compound represented by the following general formula [I], which is suitable as a dye of an optical recording medium for recording / reproducing by causing a state change by a laser beam. It is a thing.

General formula [I] (In the formula, R represents CN or CONH ₂ , X represents a hydrogen atom or an alkyl group, and R ¹ and R ² represent a lower alkyl group.) The naphthoquinone methide system represented by the general formula [I]. The compound has absorption in the wavelength band of 600 to 800 nm and a molecular absorption coefficient of 10 ⁴ to 10 ⁵ cm ⁻¹ .

The general synthesis of the naphthoquinone methide compound represented by the general formula [I] of the present invention can be carried out, for example, by the general formula [II] (Wherein R and Z are the same as defined above) and a compound of the general formula [III] (In the formula, X, Y, R ¹ and R ² are the same as defined above.) And can be produced by oxidatively condensing the hydrochloride of the compound.

The optical recording medium using the naphthoquinone methide compound of the present invention basically comprises a substrate and a recording layer containing a naphthoquinone methide compound. A pulling layer and a protective layer can be provided on the recording layer.

The substrate in the present invention may be either transparent or opaque to the laser beam used. As the material of the substrate material, a support for a general recording material such as glass, plastic, paper, plate-shaped or foil-shaped metal can be used, and plastic is preferable from various points. Examples of the plastic include acrylic resin, methacrylic resin, vinyl acetate resin, vinyl chloride resin, nitrocellulose, polyethylene resin, polypropylene resin, polycarbonate resin, polyimide resin, epoxy resin, polysulfone resin and the like.

When using a naphthoquinone methide optical material as an information recording layer in an optical recording medium, the film thickness is 100Å to 5μ.
m, preferably 1000 ° to 3 μm. As a film forming method, a vacuum deposition method, a sputtering method, a doctor blade method,
The film can be formed by a generally used thin film forming method such as a casting method, a spinner method, or a dipping method. Further, a binder can be used if necessary. Known binders such as PVA, PVP, nitrocellulose, cellulose acetate, polyvinyl butyral, and polycarbonate are used, and the amount of the naphthoquinone methide compound to the resin is preferably 0.01 or more by weight. In the case of film formation by the spinner method, the rotation speed is preferably 500 to 5000 rpm, and after spin coating, treatment such as heating or applying to solvent vapor may be performed depending on the case. In order to improve the stability and light resistance of the recording material, a transition metal chelate compound (eg, acetylacetonate chelate, bisphenyldithiol, salicylaldehyde oxime, bisdithio-α) is used as a singlet oxygen quencher.
-Diketone and the like). Further, other dyes can be used in combination as required. The other dye may be another type of naphthoquinone methide dye, a triarylmethane dye, an azo dye, a cyanine dye,
Other types of dyes such as squarylium dyes may be used.

Doctor blade method, casting method, spinner method, dipping method, in particular, as a coating solvent when forming the recording layer by a coating method such as spinner method, tetrachloroethane, bromoform, dibromoethane, ethyl cellosolve, xylene, chlorobenzene, cyclohexanone Boiling point of 120
Those having a temperature of up to 160 ° C are preferably used.

The recording layer of the optical recording medium may be provided on both sides of the substrate, or may be provided on only one side.

Recording on the recording medium obtained as described above is performed by irradiating a laser beam, preferably a semiconductor laser beam, focused to about 1 μm on a recording layer provided on both sides or one side of the substrate. In the part irradiated with the laser beam,
Thermal deformation of the recording layer such as decomposition, evaporation, and melting occurs due to absorption of laser energy.

The recorded information is reproduced by using a laser beam to read the difference in reflectance between a portion where thermal deformation has occurred and a portion where thermal deformation has not occurred.

Laser light used for the optical recording medium of the present invention is _{N 2, He-Cd, Ar} , He-Ne, ruby, semiconductor, but such a dye laser and the like, in particular, light weight, ease of handling, compactness A semiconductor laser is preferable from the viewpoint of properties and the like.

EXAMPLES The present invention will be specifically described below with reference to examples, but the examples do not limit the present invention.

Example 1 (a) Production Example The following structural formula was added to an alkaline aqueous solution in which 640 mg of sodium hydroxide was dissolved. 858 mg of the compound hydrochloride and triethylamine
0.3 ml and the following structural formula 384.4 mg of 1-naphthylmalononitrile represented by the following formula was added, and 14.89 ml of an aqueous solution of sodium hypochlorite was added dropwise thereto at room temperature. After dropping, the mixture was stirred for 10 minutes, and then the precipitate was separated and dried. After the silica gel column was decomposed (developing solvent chloroform), ethanol was recrystallized to obtain a compound represented by the following structural formula. (Yield 51%) The melting point of this compound is 135 to 136 ° C, and the absorption spectrum in the visible region (in chloroform) is λmax761 nm (ε3080
0) (FIG. 1), the elemental analysis results are as follows, and the analytical values were in good agreement with the calculated values.

(B) Recording Medium Example-1 0.15 g of the naphthoquinone methide compound obtained in the above Production Example (a) was dissolved in 10 g of tetrachloroethane and filtered through a 0.22 µ filter to obtain a solution. 1 ml of this solution was dropped on a polymethylmethacrylate (PMMA) resin substrate (52φ) and applied at a rotation speed of 600 rpm by a spinner method. After coating, it was dried at 60 ° C. for 10 minutes. The maximum absorption wavelength of the coating film was 770 nm, and the reflectance was 28% (830 nm).
The shape of the spectrum was wide. Figure 2 shows the absorption and reflection spectra of the coating film.

(C) Optical recording method-1 This coating film was irradiated with a semiconductor laser beam having a central wavelength of 830 nm at an output of 4 mW, and the width was 1.57 μm and the pit depth was 1267 Å
Pits with extremely clear contours (measured by Elionix) were formed.

This coating film was stable for more than 20 days in the accelerated test under high temperature and high humidity (60 ℃, 80% RH).

(D) Recording Medium Example-2 0.1 g of the naphthoquinone methide compound obtained in the above Production Example (a) was dissolved in 10 g of tetrachloroethane, and the solution was filtered through a 0.22 µ filter to obtain a solution. 5 ml of this solution was dropped on a PMMA resin substrate (5 inches) having a depth of 700 L and a width of 0.7 μ and a groove (groove) made of an ultraviolet curable resin, and applied by a spinner method at a rotation speed of 800 rpm. After application, at 60 ° C
Dried for 10 minutes.

(E) Optical recording method-2 4 m of 5 inch PMMA resin substrate on which the above recording medium is formed.
C / N at an output of 6 mW when irradiated with a semiconductor laser beam with a central wavelength of 830 nm with a pulse width of 500 nsec while rotating at / s.
A ratio of 50dβ was obtained. Storage stability (60 ℃, 80% RH) was also good.

Example 2 (a) Production Example The following structural formula in Example 1 was used. Instead of 858 mg of the hydrochloride of the compound represented by the following structural formula A naphthoquinone methide compound represented by the following structural formula was obtained in the same manner as in Example 1 except that 690 mg of the hydrochloride of the compound represented by (Yield 28%) The melting point of this compound is 181-183 ° C, and the absorption spectrum in the visible region (in chloroform) is λmax722nm (ε2550
0) (Fig. 3), and the elemental analysis results are as follows, which were in good agreement with the calculated values.

(B) Recording Medium Example The naphthoquinone methide compound obtained in the above Production Example (a) was applied onto a PMMA resin substrate (25φ) by a spinner method according to the method described in Example 1.

The maximum absorption wavelength of the coating film is 750 nm and the reflectance is 28%.
(830 nm). The shape of the spectrum was wide.
Figure 4 shows the absorption and reflection spectra of the coating film.

(C) Optical recording method When the above coating film was irradiated with a semiconductor laser beam having a central wavelength of 830 nm at an output of 4 mW, pits with clear contours were formed.

The storage stability (60 ° C., 80% RH) of this coating film was good.

Example 3 According to the method of Example 1, a naphthoquinone methide compound represented by the general formula [I] was synthesized.

Table 1 shows the λmax of these compounds in a chloroform solvent.

[Effects of the Invention] The naphthoquinone methide-based compound of the present invention has high solubility in an organic solvent, can be coated by coating, and has high reflectance, good contrast, and excellent storage stability. Therefore, it is extremely useful as a dye for optical recording media.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 3 show visible part absorption spectra of two examples of the naphthoquinone methide compound of the present invention, where the vertical axis is absorbance and the horizontal axis is wavelength (nm). Represents FIG. 2 and FIG. 4 show the absorption spectrum and the reflection spectrum of the coated thin film of two examples of the naphthoquinone methide compound of the present invention, where the vertical axis represents the absorbance on the left and the reflectance on the right. The axis represents wavelength (nm).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuichi Maeda Sanryo Kasei Kogyo Co., Ltd. Research Institute, 1000, Kamoshida-cho, Midori-ku, Yokohama-shi, Kanagawa

Claims (1)

[Claims] 1. A general formula [I] (In the formula, R represents CN or CONH ₂ , X represents a hydrogen atom or an alkyl group, and R ¹ and R ² represent a lower alkyl group.) A naphthoquinone methide-based compound.