JPS63274591A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To increase sensitivity, stability and membrane workability by providing an information recording layer containing a silicon naphthalocyanine compound represented by a specific formula on a substrate to form an optical information recording medium. CONSTITUTION:Carboxylic acid which has a structure of a branched or cyclic part represented by R'1COOH(R'1CO=R1), etc. is allowed to react with dihydroxy(2,3-naphthalocyanate) silicon to obtain a silicon naphthalocyanine compound represented by the formula I (R1, R2 each represent an acyl group having the same or different structure with a branched or cyclic part and carbon atoms of 4 or more). This compound is dissolved in an organic solvent such as methylene chloride to prepare a coating liquid. This coating liquid is applied to the surface of a substrate and the coating is dried to form an information recording layer thus obtaining an optical information recording medium.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical information recording medium that can record and reproduce information using a laser beam.
More specifically, the present invention relates to an optical information recording medium having an information recording layer containing a specific naphthalocyanine compound.

[Prior Art and its Problems] Conventionally, many inorganic materials such as Te alloys and Te oxides, and various organic dyes have been proposed as materials for optical information recording media that record and reproduce information using laser beams. Compared to inorganic materials, organic dyes have lipophilic properties that allow the production of non-polluting and highly sensitive media at lower cost. Examples include phthalocyanine-based, cyanine-based, merocyanine-based, squarylium-based, pyrylium salt-based, anthraquinone-based, triphenylmethane-based, etc. However, they have the necessary characteristics to be used as an optical information recording medium, that is, absorption wavelength and sensitivity.・
At present, a material that satisfies all aspects such as stability and thin film processability has not yet been found.

Semiconductor lasers currently commonly used as recording lasers mainly emit light at long wavelengths around 830 nm and short wavelengths around 780 nm. Therefore, when using these semiconductor lasers as a light source, it is necessary to use dyes that correspond to each wavelength, or to use a dye that has a wide absorption wavelength range that covers both wavelengths of light. Yes, but
Naturally, the latter is preferable.

On the other hand, among the above organic pigments, phthalocyanine pigments have long been known as blue to green pigments and are widely used as pigments with excellent stability. Among them, many proposals have been made to use copper phthalocyanine, lead phthalocyanine, titanium phthalocyanine, vanadyl phthalonoanine, tin phthalonanine, etc. as materials for optical information recording media (JP-A-55-97033, JP-A-55-97033; Publication No. 56-130742, JP-A-58-3
6490, JP-A-59-11292, etc.),
The absorption wavelength of these dyes has a maximum around 700 nm, and the absorbance is low in the emission wavelength region of a semiconductor laser (around 780 nm or 830r++n).

Therefore, methods have been proposed to broaden the absorption band and shift the entire absorption band to the longer wavelength side by using a shifting agent such as benzophenone (Japanese Patent Application Laid-open No. 59-16153), or by performing solvent treatment or heat treatment. However, the process becomes complicated and is not preferable. In addition, these metal phthalonanine dyes have poor solubility in organic solvents, etc., and cannot be formed into thin films by solution coating, etc., so they have to rely on methods such as vacuum evaporation and sputtering, which imposes significant restrictions on their use. Ta.

Regarding the longer wavelength of phthalocyanine compounds, its π-
Naphthalocyanine derivatives can be considered as a form that further expands the electronic conjugation region, and it is already known that this group of compounds with a naphthalocyanine skeleton has a high absorbance in the targeted 800 ns vicinity [rnorg, Chill,
Acta, ,44. L209 (1980): Zh,
0bshch, Khit, 42(3), 696(1
972); J, At1. Chew, Soc, ,
No. 06, 7404 (1984)].

However, naphthalocyanine itself and its metal salts are more difficult to dissolve in common organic solvents than the corresponding phthalocyanine compounds, and this, combined with the difficulty of synthesis, has hindered the effective use of this compound.

In recent years, efforts have been made to improve the solubility of this substance (U.S. Pat.
Publication No. 25886, J. At Chew.

Soc, IO6, 7404 (1984), JP-A-6
1-177287, JP-A-61-177288, and JP-A-5O-184565), but all of these methods are complicated, or the synthesized compound has insufficient solubility. In addition to having drawbacks, the absorption wavelength only covers around 780 nm, and the sensitivity to the 830nI11 laser tip is low.

As mentioned above, especially in the emission wavelength region of semiconductor lasers (7
80 to 830 nm) with high sensitivity.
At present, no material has yet been found that satisfies all the conditions necessary for practical use, such as excellent stability, high thin film processability, and easy synthesis.

[Means for Solving the Problems] The present inventors have conducted intensive studies to solve the above-mentioned problems of the prior art, and as a result, we have developed a specific nanostructure into which an acyl group having a branched or cyclic partial structure has been introduced. An optical information recording medium using a phthalocyanine compound is 780na+,
It was discovered that the compound has excellent absorption characteristics, processability, and stability for both wavelengths of 830 nm, especially the wavelength of 8301, and has the advantage that the compound is easy to synthesize.
This led to the present invention.

That is, the present invention provides an optical information recording medium comprising an information recording layer provided on a substrate, in which the information recording layer has the formula: (where RI and Rt may be the same or different, and are saturated or unsaturated carbon Provided is an optical information recording medium containing a solicon naphthalocyanine compound represented by (representing an acyl group having a branched or cyclic partial structure of 4 or more).

A preferred embodiment of the present invention is R+.

A case where a compound having an acyl group having a branched or cyclic partial structure having 8 to 36 carbon atoms is used as R1 can be mentioned, and particularly preferred embodiments include:
As R,, R1, a compound having an acyl group having a branched or cyclic partial structure having 16 to 30 carbon atoms can be used.

The silicon naphthalocyanine compound represented by the above formula (1) of the present invention has dihydroxy (2,3-naphthalocyanate) silicon containing Rl'COOH (Rl'CO=R
1), R*' COOH (Rt' CO= Rt
) can be easily obtained by reacting a carboxylic acid having a branched or cyclic partial structure represented by:

The raw material carboxylic acids used include 2-ethylhexanoic acid, 2-hebutylundecanoic acid, 2-(1,3,3
-trimethylbutyl)-5,7,7-drimethyloctanoic acid, 2-dodecylmyristic acid, 2,4-dibutyldecanoic acid, 2-butyl-4,4゜6.6.8-pentamethylnonanoic acid, 2 -hexyl-4,4,6-trimethyl-
Examples include 6-heptenoic acid, 8-hydroxycarbonyltricyclo[5,2,1,0""]decane, 4-butylcyclohexane-1-carboxylic acid, and the like.

Examples of the silicon naphthalocyanine compound represented by the formula (1) of the present invention include bis(2-ethylhexanoyloxy)(2,3-naphthalocyanato) silicon, bis(2-hebutylundecanoyl Oxy X2,3
-naphthalocyanate) silicon, bis(2-(1,3
,3-trimethylbutyl)-5,7,7-)limethyloctanoyloxy](2゜3-naphthalocyanato)silicon, bis(2-dodecylmyristoyloxy)(2
,3-naphthalocyanate) silicon, bis(2,4-
dibutyldecanoyloxyX2,3-naphthalocyanate) silicone, bis(2-butyl-4,4,6,6,8
-pentamethylnonanoyloxy) (2,3-naphthalocyanato) silicon, bis(2-hexyl-4,4゜6-trimethyl-6-heptanoyloxy) (2゜3-
naphthalocyanate) silicon, bis(tricyclo[5
,2,1,0'°6codecane-8-carboxy) (2,
Examples include, but are not limited to, silicon (3-naphthalocyanate), bis(4-t-butyl-cyclohexanecarboxy) (2,3-naphthalocyanate) silicon, and the like.

The silicon naphthalocyanine compound represented by the above formula (1) has an expanded π-electron delocalized region compared to phthalocyanine dyes, so it has a near-infrared wavelength of around 800 nI11, which is a longer wavelength region than phthalocyanine dyes. It shows absorption in the outer region. Furthermore, these compounds are soluble in general-purpose organic solvents such as halogenated hydrocarbons such as methylene chloride, chloroform, and carbon tetrachloride, aromatic hydrocarbons such as toluene and benzene, and ketone compounds such as acetone, methyl ethyl ketone, and cyclohexanone. By dissolving it in an appropriate solvent, it is possible to apply a thin film onto a substrate by spraying, roller coating, dipping, spin coating, or the like.

At this time, the silicon naphthalocyanine compound alone can be applied in a thin film, but a suitable polymeric binder may also be used in combination. Examples of the polymer binder mentioned here include thermoplastic resins such as nitrocellulose, polystyrene, polyethylene, polyvinyl acetate, polyvinyl alcohol, polyurethane, polyamide, and polyester.

Further, in combination with the silicon naphthalocyanine compound represented by the above formula (1), it is also possible to use other organic dyes that are soluble in the same organic solvent.

Further, as other thin film processing methods, methods such as vacuum evaporation and sputtering can be used.

In the present invention, the substrate material supporting the recording layer containing the silicon naphthalocyanine compound may be a thermoplastic resin such as vinyl chloride resin, acrylic resin, polyolefin resin, polycarbonate resin, or polyvinyl acecool resin, or epoxy resin or unsaturated polyester. Resin, thermosetting resin such as vinyl ester resin, glass, and metals can be used. Using these materials, a thin film can be processed by the method described above on the mirror surface of a molded substrate or on a surface in which a guide groove pattern (pre-group) is carved. Alternatively, the substrate may have a structure in which a photocurable resin is laminated on a flat plate molded from the above material, and the guide groove pattern is transferred onto the surface of the photocurable resin layer.

The thickness of the recording layer formed on these substrates is 0.01 to 5 μm.
It may be within the range of l, preferably within the range of 0.05 to 1 μm. Furthermore, a reflective layer, a protective layer, etc. are provided to constitute a disc-shaped or a tape-shaped optical information recording medium, but the present invention does not care about these configurations.

By irradiating the optical information recording medium of the present invention produced in this way with a laser beam, bits are formed in the irradiated area and information can be recorded and reproduced.
The laser beam used varies depending on the absorption wavelength of the recording layer.
, He-Ne, Ar, ruby, dye, semiconductor, and other laser beams can be selected. Among them, Ga-Al-A
A system using a laser having an oscillation wavelength in the near-infrared region, such as an S semiconductor laser (oscillation wavelength 780 nm), is suitable.

[Examples] The present invention will be specifically described below with reference to Examples; however, the present invention is not limited to these Examples.

Note that dihydroxy(2,3
- naphthalocyanate) silicon is described in the literature (J, As,
Chew, Soc, 106.7404 (1984))
It was synthesized according to the description.

Example I Dihydroxy(2,3-naphthalocyanate) silicon 250m9 (0,323a*ol), 2-hebutylundecanoic acid 3.0f (12,1a@ol) in tetralin (
The solution was refluxed for 2 hours. After cooling to room temperature, 90zQ of ethanol was added, and the resulting precipitate was collected by filtration (28
1.6119). This precipitate was separated using a silica gel column and the desired bis(2-hebutylundecanoyloxy 267xy (0,2041 sol, 63°2%) was obtained.

This was recrystallized from a hexane-chloroform mixed solvent to obtain green columnar crystals (mp=281.5-285°C).

The obtained green solid is soluble in solvents such as chloroform, methylene chloride, carbon tetrachloride, toluene, xylene, cyclohexanone, methyl ethyl ketone, etc., and as a result of absorbance analysis of methylene chloride solution, absorption maximum at 798r++e (ε=2 .2XIO'12/mol -CI)
showed that.

This silicon naphthalocyanine compound and nitrocellulose were dissolved in cyclohexanone at a weight ratio of III, and coated on a transparent plate made of epoxy resin with a thickness of 1.2 mm by a spin cord method to a thickness of 0.1 mm! A uniform membrane of μ-intestine was prepared.

This thin film has a particularly strong and wide absorption wavelength band between 760 and 870r+I11 (λ1ax=829npeng), and has a wavelength of 7
80 nms beam diameter t, OU- laser light (5 m
When irradiated with W), clear bits were formed. Similarly, clear bits were also formed using a laser beam (5 mW) with a wavelength of 830 nm.

Example 2 Dihydroxy (2,3-naphthalocyanate) silicon 1.09 (1,29111 mol), 2-(1,
A solution of 11.01 g (38.7 mmol) of 3,3-)lyntylbutyl)-5,7,7-drimethyloctanoic acid in tetralin (30 molecules) was refluxed for 2 hours, and then the solvent was distilled off under reduced pressure. The methylene chloride-insoluble portion in the residue was removed using a silica gel column, and the solvent was distilled off to obtain a greenish-brown oil.

This is treated with a methanol/water system to obtain the desired bis-t2-
(1,3,3,-trimethylbutyl)-5,7°7-drimethyloctanoyloxyco(2,3-naphthalocyanate) silicone 40619 (0,310 mmol 1.
24, 1%) was obtained. This material was a greenish-brown powder.

This green solid is soluble in solvents such as methylene chloride, toluene, cyclohexanone, and cyclohexane, and as a result of absorbance analysis of the methylene chloride solution, it has a wavelength of 808 nm.
extremely strong absorption maximum (ε=1゜9
Q/moI・CI).

This silicon naphthalocyanine compound and polystyrene resin were dissolved in chloroform at a weight ratio of 1:1, and a uniform film with a thickness of 0.1 μm was formed on a glass plate by a spin cord method.

This thin film exhibits strong absorption with a maximum at 827 nm, and a laser beam with a wavelength of 830 nm and a beam diameter of 1.0 μm (
When irradiated with 5+aW), clear pits were formed.

The above laminate was left in an environment of 60° C. and 90% RH, and its light absorption properties were tracked over time, but no change in properties was observed even after 2000 hours.

Comparative Example 1 J, Aa+, Chewl, Soc, 106.7404
(f984), bis(tri-n-hexylsiloxyX2,3-naphthalocyanate) silicon was synthesized.

The obtained green solid had a melting point of 276 to 279°C and was soluble in solvents such as methylene chloride, chloroform, carbon tetrachloride, toluene, and cyclohexanone. As a result of absorbance analysis of the methylene chloride solution, extremely strong absorption (ε=2.5X105&/sol -c) was observed for 772ni+.
m) was shown.

This silicon naphthalocyanine compound and polystyrene resin were dissolved in chloroform at a weight ratio of 1:1, and a uniform film with a thickness of 0.1 um was formed on a glass plate by a spin cord method. This thin film exhibited strong absorption with a maximum at 778 nm, and clear pits were formed when it was irradiated with laser light (5 mW) with a wavelength of 780 nm and a beam diameter of 1.0 μm. However, when laser light (5-W) with a wavelength of 830 nm and a beam diameter of 1.0 μm was used, the pits were small and partially unclear.

Further, when the sample was left in an environment of 60° C. and 90% RH, clear aggregation of the dye was observed in about one week.

[Effects of the Invention] As described above, the optical information recording medium of the present invention uses a specific silicon naphthalocyanine compound having a branched chain or a cyclic moiety in the recording layer. It can be dissolved in a variety of solvents, and can be applied not only to vacuum evaporation and sputtering methods, but also to solution coating methods.
To easily form a thin film on a suitable substrate.

The obtained thin film has a suitable absorption spectrum and high sensitivity to light in the near-infrared region, and also exhibits sufficient aggregation resistance, so that it can be suitably used as an optical information recording medium.

Claims (1)

[Claims] 1. In an optical information recording medium comprising an information recording layer provided on a substrate, the information recording layer has the formula: ▲ Numerical formula, chemical formula, table, etc. ▼ (1) (In the formula R_1, R_2 may be the same or different,
Represents a saturated or unsaturated acyl group having 4 or more carbon atoms and having a branched or cyclic partial structure. ) An optical information recording medium containing a silicon naphthalocyanine compound represented by: 2. The optical information recording medium according to claim 1, wherein R_1 and R_2 are acyl groups having a branched or cyclic partial structure having 8 to 36 carbon atoms. 3. The optical information recording medium according to claim 1, wherein R_1 and R_2 are acyl groups having a branched or cyclic partial structure having 16 to 30 carbon atoms.