JPS6394893A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To cover widely the wave area for emission of semiconductor laser with a good sensitivity to obtain superior stability and film processability, by a method wherein an information recording layer contains a specific silicon naphthalocyanine compound. CONSTITUTION:An information recording layer contains a silicon naphthalocyanine compound shown by a formula (I) (where R1 and R2 may be either the same or different and represent 4 or more C branched alkyl, alkenyl, or cycloalkyl). This silicon naphthalocyanine compound can be easily obtained by performing the reaction of dihydroxy(2,3-naphthalocyanate)silicon with a branched alcohol shown by R1OH, R2OH. Because the compound has branched chain alkyl or alkenyl, an optical information recording medium has superior light absorption characteristics to a wavelength of 780-830nm. Furthermore, the compound having a solubility in a general-purpose organic solvent such as halogenated hydrocarbon, aromatic hydrocarbon, and ketone compound can dissolve in these solvents to be coated on a substrate in film form by a spray or roller coating etc.

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.

[Conventional technology 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 the potential to produce pollution-free and highly sensitive media at lower cost. Examples include phthalocyanine-based, cyanine-based, merocyanine-based, squarylium base, pyrylium salt-based, anthraquinone-based, triphenylmethane-based, etc. However, they have the necessary characteristics for use as optical information recording media, such as absorption wavelength, sensitivity,
At present, no material has yet been found that satisfies all aspects such as stability and thin film processability.

Currently, semiconductor lasers 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. For example, many proposals have been made to use copper phthalocyanine, lead phthalocyanine, titanium phthalocyanine, vanadyl phthalocyanine, tin phthalocyanine, etc. as materials for optical information recording media (Japanese Unexamined Patent Publication No. 55-97033,
6-130742, JP-A-58-36490, JP-A-59-11292, etc.), their absorption wavelengths have a maximum near 700 nm, and the emission wavelength region of semiconductor lasers (780 nm or 830 nm) (near), the absorbance is low.

Therefore, methods have been proposed to widen the absorption band and shift the entire absorption band to longer wavelengths by using a shifting agent such as hensifenone (Japanese Patent Application Laid-Open No. 16153/1982), or by performing solvent treatment or heat treatment. However, the process becomes complicated, which is not preferable. In addition, these metal phthalocyanine dyes have poor solubility in organic solvents, etc., and cannot be formed into thin films by solution coating, etc., so they have limitations in use that force them to use only methods such as vacuum evaporation and sputtering. It was also big.

Regarding longer wavelengths through derivatization of phthalocyanine, naphthalocyanine derivatives can be considered as a form in which the π-electron conjugation region is further expanded, and this group of compounds with a naphthalocyanine skeleton has a high absorbance in the targeted vicinity of 800 nm. is already known (Inorg, ChiI
I+, ^cta,, 44. L209 (I980)
; Zh, 0bshch, Khim,, 42(3)
, 696 (I972); J, Am, CheIl
, Soc, 106.7404 (I984)).

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

In recent years, efforts have been made to improve the solubility of this substance (U.S. Pat.
No. 25886, J, Am, Chem, Soc, +1
0 loss 7404 (I984), JP-A-61-1772
No. 87, JP-A No. 61-177288), all of these methods have drawbacks such as complicated synthesis or insufficient solubility of the synthesized compound, and the absorption wavelength is only around 780 nm. , and has low sensitivity to 830 nm laser light.

As mentioned above, especially in the emission wavelength region of semiconductor lasers (7
No material has yet been found that satisfies all the conditions necessary for practical use: covering a wide range of 80 to 830 nn+ with good sensitivity, excellent stability, high thin film processability, and easy synthesis. is the current situation.

[Means for solving problems]

The present inventors conducted intensive studies to solve the above-mentioned problems of the prior art, and found that an optical information recording medium using a specific naphthalocyanine compound having a particularly branched alkyl group or alkenyl group. 780nm, 830nm
Excellent absorption characteristics, processability, and stability for both m wavelengths,
Furthermore, it was discovered that the compound has the advantage of being easy to synthesize, leading to the present invention.

That is, the present invention provides an optical information recording medium comprising an information recording layer provided on a substrate, characterized in that the information recording layer contains a silicon naphthalocyanine compound represented by the following formula (I). The present invention provides an optical information recording medium.

(In the formula, RI+Rz may be the same or different, and represents a branched alkyl group, alkenyl group, or cycloalkyl group having 4 or more carbon atoms.) In a preferred embodiment of the present invention, RI+R2 has 8 to 36 carbon atoms. A particularly preferred embodiment includes the use of a compound having a branched alkyl group, alkenyl group, or cycloalkyl group.
Examples include a case where a compound having a branched alkyl group, alkenyl group, or cycloalkyl group having 16 to 30 carbon atoms is used as R+ and Rt.

The silicon naphthalocyanine compound represented by the formula (I) of the present invention can be easily obtained by reacting dihydroxy (2,3-naphthalocyanate) silicon with a branched alcohol represented by R+OB or RJH. .

The branched alcohols used as raw materials include 2-ethylhexyl alcohol, 2-hebutyldodecyl alcohol, 2-(I,3,3-)limethylbutyl)-5,7,
7-trimethyloctyl alcohol, 2-dodecylmyristyl alcohol, 2.4-dibutyldecyl alcohol, 2-butyl-4,4,6,6,8-pentamethylnonyl alcohol, 2-hexyl-4,4,6- ) Limethyl-6-hebutenyl alcohol, 8-hydroxymethyltricyclo[5,2,1,0''°6]decane, 4-t-butyl-1-hydroxymethylcyclohexane, and the like.

Specific examples of the silicon naphthalocyanine compound represented by formula (I) used in the present invention include eva, bis(2
-ethylhexyloxy)

3-naphthalocyanate) silicone, bis(2-hebutyldodecyloxy)(2,3-naphthalocyanate) silicone, bis(2-(L3,3-)limethylbutyl)
-5,7,T-trimethyloctyloxy) (2,
3-naphthalocyanate) silicone, bis(2-dodecylmyristyloxy)(2゜3-naphthalocyanate)
Silicon, bis(2゜4-dibutyldecyloxy)(2
, 3-naphthalocyanate) silicon, bis(2-butyl-4,4゜6.6.8-pentamethylnonyloxy)
(2,3-naphthalocyanate) silicon, bis(2-
hexyl-4,4,6-)limethyl-6-hebutenyloxy)(2,3-naphthalocyanato)silicon, bis(tricyclo(5,2,1,0”6)decyl-8-methyloxy)( 2,3-naphthalocyanate) silicon,
Examples include, but are not limited to, bisque 4-t-butyl-cyclohexyl-1-methyloxy) (2,3-naphthalocyanate) silicon.

The silicon naphthalocyanine compound represented by the above formula (I) has an expanded π-electron delocalized region compared to phthalocyanine dyes, so it has a near-infrared wavelength of around 800 nm, which is a longer wavelength region than phthalocyanine dyes. It shows absorption in the outer region. Furthermore, these compounds include halogenated hydrocarbons such as methylene chloride, chloroform, and carbon tetrachloride, toluene,
It is soluble in general-purpose organic solvents such as aromatic hydrocarbons such as benzene, ketone compounds such as acetone, methyl ethyl ketone, and cyclohexanone, and by dissolving them in an appropriate solvent, it can be used for spraying, roller coating, dipping, and spin coating. A thin film can be coated on a substrate by methods such as the following. At this time, the silicon naphthalocyanine compound alone can be applied as 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.

Moreover, it is also possible to use other organic dyes soluble in the same organic solvent together with the silicon naphthalocyanine compound represented by the formula (I).

Further, other thin film coating methods such as vacuum deposition and sputtering can also be used.

In the present invention, the substrate material supporting the recording layer containing the silicon naphthalocyanine compound is a thermoplastic resin such as vinyl chloride resin, acrylic resin, polyolefin resin, polycarbonate resin, or polyvinyl acetal resin, or epoxy resin or unsaturated polyester resin. , thermosetting resins such as vinyl ester resins, glass, and metals can be used. Using these materials, a thin film can be applied by the method described above onto the mirror surface of a molded substrate or onto 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 5-5-
, preferably in the range of 0.05 to 1-. Furthermore, a reflective layer, a protective layer, etc. are provided to constitute a disk-shaped or sheet-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, pits are formed in the irradiated area, and information can be recorded and reproduced.
The laser beam used is N2 depending on the absorption wavelength of the recording layer.
．． He-Ne.

^r, ruby, dye, semiconductor, etc. laser beams can be selected. Among them, Ga-Al-As semiconductor laser (
A system using a laser having an oscillation wavelength in the near-infrared region, such as an oscillation wavelength of 780 nm, is suitable.

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

Note that dihydroxy(2,3
- naphthalocyanate) silicon is described in the literature (J, Am
, Chem, Soc, 106.7404 (I98
It was synthesized according to the description in 4)).

Example 1 Dihydroxy(2,3-naphthalocyanate) silicone 296 mg (0,382 mmol), 2-(I,
3,3-trimethylbutyl')-5,7,7-)dimethyloctan-1-ol 3.0 g (I1,1 mm
ol) in tetralin (I0mZ) was refluxed for 1.5 hours. After cooling to room temperature, 30 ml of ethanol was added and the precipitate was collected by filtration. This precipitate was separated using a silica gel column (filtered with toluene), and 177 mg (0,13
8 mmol, 36.2%) was obtained. The product was a green powder with a melting point of about 275°C at this point. Attempts at purification by recrystallization were unsuccessful.

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 was found to be 775 nm.
extremely strong absorption maximum (ε-1,8X105I!/mo
icm).

This silicon naphthalocyanine compound and polystyrene resin were dissolved in chloroform at a weight ratio of 1:1, and placed on a glass plate with a spin code method to a thickness of 0.5 mm. A uniform film of the ban was prepared. This thin film exhibits strong, broad-band absorption with a maximum at 778 nm, with a wavelength of 805 nm and a beam diameter of 1.0 nm.
- When irradiated with laser light (5i), clear pits were formed. Laser light with a wavelength of 803 nm (5 mW)
However, a clear focus was formed as well.

The above laminate was left in an environment of 60° C. and 90% RH, and its light absorption characteristics were orally monitored, but almost no change was observed even after 2000 hours. Further, even in a test in which the dye was left under normal sunlight for a day, no reaggregation of the dye was observed, and no problems occurred.

Example 2 250 mg of dihydroxy(2,3-naphthalocyanate) silicon (0,3231111101), 3.0 g of 2-hebutyldodecane-1-ol (I1,1m
mol) of tetralin (Loaf) solution was refluxed for 2 hours. After cooling to room temperature, add ethanol 30II+7,
The resulting precipitate was collected by filtration (281.6 mg). This precipitate was separated using a silica gel column.Toluene:ethyl acetate=95:5. 267 mg (0,209 mmol, 64.6%) of the target dialkoxy (2,3-naphthalocyanate) silicone was obtained. This was recrystallized from a hexane-chloroform mixed solvent to obtain green columnar crystals.

n+p=281.5-285°C The obtained green solid is soluble in solvents such as chloroform, methylene chloride, carbon tetrachloride, toluene, xylene, cyclohexanone, and methyl ethyl ketone, and as a result of absorbance analysis of the methylene chloride solution, Maximum absorption at 798 nm (ε-2, 2×105Il/l1O1-CIll)
showed that.

This silicon naphthalocyanine compound and nitrocellulose were dissolved in cyclohexanone at a weight ratio of 1:1, 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 0.11 mm. A uniform film was created.

This thin film has a particularly strong and broad absorption wavelength band between 760 and 870 nm (λmax = 829 nm);
When irradiated with a laser beam (51) of 80 nm and a beam diameter of 1.0, clear pits were formed. Also wavelength 83
Clear pits were similarly formed even when a 0 nm laser beam (5 mW) was used.

Further, no change in properties was observed in the storage test under the same high temperature conditions as in Example 1 and under sunlight.

Example 3 A polycarbonate transparent substrate with a thickness of 1.2 mm was placed in a vacuum chamber, and sialkoxy (2,3
- naphthalocyanate) placed on the vapor deposition port containing the silicone, and a current source tangentially connected to this port to open the vacuum chamber for approximately 10 min.
It was evacuated to -6 mmHH.

The port was heated to about 300° C., the shutter was opened, and the dye was deposited at a rate of about 1 person/second to form a uniform thin film with a thickness of 0.071 Bm.

This thin film has a particularly strong and wide absorption wavelength band from 750 to 860 nm (λwax = 830 nm), and is similar to the semiconductor laser (830 nm, 780 nm) as in Example 2.
When a laser beam with a beam diameter of 1.0-15IIIH was irradiated using a laser beam with a diameter of 1.0-15IIIH, a clear focus was formed for both wavelengths.

Further, no change in properties was observed in the storage test under the same high temperature and high humidity conditions as in Example 1 and under sunlight.

Comparative Example I J, Am, Chem, Soc, + publication 6.7404
(I984), bis(tri-hexylsiloxy)(2,3-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 at 772 nm (ε=2.5 Xl051/mol-cm
)showed that.

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 mm was formed on a glass plate by a spin cord method. This thin film showed strong absorption with a maximum at 778 nm, and when it was irradiated with laser light (5 mW) with a wavelength of 780 nm and a beam diameter of 1.0 tm, clear pits were formed. However, when using laser light (5 mW) with a wavelength of 830 nm and a beam diameter of 1.0, the pits are small.
And some parts were unclear.

〔Effect of the invention〕

As described above, the optical information recording medium of the present invention uses a specific branched-chain silicon naphthalocyanine compound in the recording layer, which is easy to synthesize and can be dissolved in various organic solvents. A thin film can be easily formed on a suitable substrate by not only vacuum evaporation and sputtering methods but also solution coating methods.

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

Claims (1)

[Scope of Claims] 1. An optical information recording medium comprising an information recording layer provided on a substrate, wherein the information recording layer contains a silicon naphthalocyanine compound represented by the following formula (I). An optical information recording medium characterized by: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R_1 and R_2 may be the same or different,
(represents a branched alkyl group, alkenyl group or cycloalkyl group having 4 or more carbon atoms) 2, R_1 and R_2 are a branched alkyl group, alkenyl group or cycloalkyl group having 8 to 36 carbon atoms Claim 1 The optical information recording medium described in Section 1. 3. The optical information recording medium according to claim 1, wherein R_1 and R_2 are branched alkyl groups, alkenyl groups, or cycloalkyl groups having 16 to 30 carbon atoms.