JPH0460144B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a dye material that exhibits absorption in the near-infrared light region, and more particularly to a dye material that is particularly useful for electronic devices.

(Prior art and its problems) In recent years, dyes that absorb in the near-infrared region have attracted attention. This is because desirable effects can be expected for industrial applications such as energy conversion materials using sunlight, recording materials using laser beams, and printing and photographic materials. The characteristics that a material should have differ depending on the individual application, but the basic characteristics are that it has high absorption in the near-infrared region and is chemically stable. Furthermore, depending on the field of application, it is used in the form of a film, so it must be easy to form a film under given conditions. Several such materials have been developed so far. Examples include squarylium, cyanine dyes, metal phthalocyanines, platinum bis(dithio α-diketone) complex compounds, and the like. Squarylium has the problem of low absorption rate and poor condition of the formed film, while cyanine dyes have the problem of becoming chemically unstable when the molecular chain is lengthened to increase the absorption rate of near-infrared light. When metal phthalocyanine forms a film, it becomes amorphous and has problems with its long-term stability, that is, crystallization, and platinum bis(dithio-alpha-diketone) complex compounds have poor film-forming properties and are chemically unstable. There is a problem with that. As described above, the conventionally developed near-infrared light absorbing dyes have some problems and are not suitable for practical use.

(Objective of the Invention) An object of the present invention is to provide a dye material that has large absorption in the near-infrared region, is chemically stable, and is easy to form into a film.

(Structure of the invention) That is, the present invention has the general formula [] (In the formula, X represents OR, NHR, SR. (Here, R
represents an alkyl group or a benzyl group. )) is a naphthoquinone dye material.

(Detailed explanation of the structure) Specific examples of X in the naphthoquinone dye represented by the general formula [] include OCH ₃ , OC ₂ H ₅ ,
_{OC3H7 , OC4H9 , OC5H11 , OC6H13 , OC7H15 ,}
Alkoxyl groups such _{as OC8H17} , _{OC9H19 , OC10H21 , NHCH3 , NHC2H5 , NHC3H7 , NHC4H9 ,}
NHC ₅ H ₁₁ , NHC ₆ H ₁₃ , NHC ₇ H ₁₅ , NHC ₈ H ₁₇ ,
Alkylamino groups such as NHC ₉ H ₁₉ and NHC ₁₀ H ₂₁ ,
benzylamino group (NHCH ₂ C ₆ H ₅ ) and SCH ₃ ,
Substituents selected from SC ₂ H ₅ , SC ₃ H ₇ , SC ₄ H ₉ and the like.

An example of the synthesis of the naphthoquinone dye represented by the general formula [] is shown below.

(Synthesis example) 2,3-dichloronaphthazarin and alcohol,
Benzylamine, alkylamine, etc. are reacted to synthesize the corresponding 6-X-2,3-dichloronaphthazarin. The case where X is a methoxyl group will be explained below.

6-methoxy-2,3-dichloronaphthazarin
Dissolve 290 mg (1 mmol) in 65 ml of ethanol with heating. This is called liquid A. to 20ml of ethanol
Dissolve 125 mg (2.2 mmol) of KOH and add 270 mg (2.2 mmol) of 0-aminothiophenol to convert it into K salt. This is called liquid B. Add solution A to solution B and stir at room temperature for several hours (about 5 hours). Crystals will precipitate, but add concentrated hydrochloric acid to make them weakly acidic. After washing with water and drying, 440 mg of crude product is obtained. When recrystallized in chloroform
2-Methoxy-5,8-bisanilino-6,2′,7,2″-dithio-1,4-naphthoquinone [] (mp > 300°C) is obtained in 80% yield. The identification was confirmed by mass spectrometry. This was done through elemental analysis.

(1) Mass spectrometry (relative intensity) 430 (100), 398 (29), 387 (38) (2) Elemental analysis Calculated values C: 64.17%, N: 6.51%, S: 14.89%, H: 3.28% Experiment Values C: 64.36%, N: 6.48%, S: 14.92%, H: 3.29% Next, 2-benzylamino-5,8-bisanilino-6,2′,7,2″-dithio-1,4-naphthoquinone Yield for [] (mp=242-245℃)
It could be synthesized at 63.4%, and the following analytical results were obtained.

(1) Mass spectrometry (relative intensity) 523 (17) (naphthoquinone + H ₂ O), 505 (63),
490 (42), 415 (75), 400 (100) (2) Elemental analysis Calculated values C: 68.89%, N: 8.31%, S: 12.68%, H: 3.79% Experimental values C: 68.75%, N: 8.34 %, S: 12.64%, H: 3.80% Next, 2-butylamino-5,8-bisanilino-6,2′,7,2″-dithio-1,4-naphthoquinone [] (mp = 230-231°C ) could be synthesized with a yield of 81.7%, and the following analytical results were obtained.

(1) Mass spectrometry (relative intensity) 489 (33) (naphthoquinone + H ₂ O), 471 (100),
456 (24), 428 (28), 415 (13), 366 (28), 323
(24) (2) Elemental analysis Calculated values C: 66.22%, N: 8.91%, S: 13.60%, H: 4.49% Experimental values C: 66.42%, N: 8.95%, S: 13.65%, H: 4.50% It was confirmed that each item was the intended object.

These compounds exhibit large absorption in near-infrared wavelengths of 700 to 800 nm. Using chloroform as a solvent,
When the absorption spectra of these compounds in the visible and near-infrared light regions are measured, the maximum absorption wavelengths λ _nax are 567, 617, 673, and 738 nm in [], 568, 619, 673, and 735 nm in [], and 568, 619, 673, and 735 nm in [].
They were 568, 622, 673, and 735 nm.

In addition, in the above general formula [], it is also possible to oxidize S to SO or SO ₂ , which can further deepen the color.

In order to specifically demonstrate the industrial effectiveness of the naphthoquinone dye represented by the general formula [], a recording material using a laser beam will be described below as an application example. Recording methods using laser light are divided into permanent recording type and reversible recording type. When a dye is used as a recording material, it belongs to the permanent recording type, and it is a thin film (usually
A laser beam is focused and irradiated onto the surface (thickness of 1μm or less),
Recording is done by forming holes in a thin film.
Reproduction (reading) of recorded information is performed by lowering the output of laser light to such an extent that no recording occurs even if the laser light is continuously irradiated, and by detecting reflected light or transmitted light from the thin film. In the case of reflected light detection, the reflectance from the area where holes are formed (pits) is generally lower than the reflectance from surrounding areas where holes are not formed, so this change in reflectance is used to perform playback. conduct. The characteristics required of a permanent recording type recording material based on such basic principles are as follows.

As a first characteristic, the recording material must have high recording sensitivity. That is, holes need to be formed with low laser beam intensity and short irradiation time. Although the mechanism of pore formation has not been theoretically elucidated, it is thought to be due to the combined effects of evaporation, decomposition, and melting due to the temperature rise of the irradiated area. In order to have high sensitivity, it is first necessary to absorb laser light and cause a temperature rise. Therefore, a material with high absorption rate is required. As the laser light source used, a semiconductor laser is used because the device is small and does not require a large amount of power. Since the oscillation wavelength of a semiconductor laser is around 800 nm, it has absorption in this wavelength range. When the magnitude of absorption is expressed by the extinction coefficient k, its desirable value is 0.5 or more.
In order to have high sensitivity, in addition to having a large extinction coefficient and being able to expect a high temperature rise, it is also required that the temperature of evaporation, decomposition, melting, etc. is low. However, in practical terms, if these temperatures are too low, they lack stability and are difficult to handle, so the desirable temperature range is 100 to 300°C.

Optical recording media are usually formed in the form of a thin film on a disc-shaped or tape-shaped substrate made of glass, synthetic resin, aluminum alloy, or the like. Examples of thin film forming methods include vacuum deposition methods such as evaporation and sputtering, and methods of applying a solution dissolved in a solvent to a substrate. A desirable film forming method is a vacuum deposition method that does not impose restrictions on the substrate. Resistance heating vapor deposition is commonly used as a vacuum deposition method for organic substances. In order for a film to be formed by vapor deposition, it is necessary to have a vapor pressure (10 ^-3 Torr) required for deposition below the decomposition temperature. Desired deposition rates are 10-1000 Å/min.

Organic films formed by vapor deposition are generally amorphous. When such a film is taken out into the air, depending on the material, agglomeration may be observed in the film due to contact with air, particularly moisture. Such deterioration is not desirable as a recording medium. In particular, permanent recording media are required to have a lifespan of 10 years or more under normal conditions. Such long-term lifespans are generally measured by accelerated tests.

The basic characteristics required for permanent recording media have been explained above, but to summarize, they have absorption at the laser light wavelength, moderately low evaporation, decomposition, and melting temperatures, can be formed by vapor deposition, and have a long life. It happens. Examples will be described below to specifically demonstrate that the dye material of the present invention satisfies these requirements and is excellent as a permanent recording medium material.

Example 1 50 mg of the dye of compound [] was placed in a resistance heating boat made of molybdenum, and vapor deposition could be carried out on an acrylic substrate at a boat temperature of 240° C. under a degree of vacuum of 1×10 ⁻⁵ Torr or less. The deposition rate is 100 Å/min. Create three films with a film thickness in the range of 200 to 1100 Å, and
The reflectance, transmittance, and absorption of each film at 780 nm were measured, and the extinction coefficient k was determined to be 0.5 from the film thickness dependence of these optical properties.

To investigate the stability of the membrane, accelerated tests were performed in the temperature range of 50-90°C. Deterioration of the film was observed using an optical microscope with a magnification of 2000 times, and determined by the presence or absence of aggregated particles. From this, the lifespan at room temperature (25°C) was determined.
The lifespan of this pigment film was found to be over 10 years.

Example 2 An experiment similar to Example 1 was conducted on compound [], and the deposition temperature was 300 to 320°C and the deposition rate was 100 Å/
minute, extinction coefficient (λ=780nm) 0.5, and lifespan of over 10 years.

Example 3 The same experiment as in Example 1 was conducted on the compound [], and a vapor deposition temperature of 250° C., a vapor deposition rate of 100 Å/min, an extinction coefficient (λ=780 nm) of 0.5, and a life of more than 10 years were obtained.

(Effect of the invention) As described above, the naphthoquinone dye of the present invention is
As a permanent recording type optical recording material, it has significantly superior properties compared to conventional dyes, and has many industrial advantages.

Claims (1)

[Claims] 1. General formula [] (In the formula, X represents OR, NHR, SR. (Here, R
represents an alkyl group or a benzyl group. )) A naphthoquinone dye material.