JP2635841B2 - Optical recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium used for recording and storing information.

[0002]

2. Description of the Related Art Conventionally, a compact disc-write once (Compact Disc-W) comprising a recording layer (light absorbing layer), a light reflecting layer and a protective layer laminated on a substrate.
A write-once (hereinafter abbreviated as CD-WO) optical recording medium has been known (Japanese Patent Application Laid-Open No. 58-183296,
JP-A-53-46019, JP-A-58-37851 and JP-A-1-159842.

[0003]

However, Japanese Patent Application Laid-Open No.
With copper phthalocyanine (Oleozol Fast Blue EL, manufactured by Sumitomo Chemical Co., Ltd.) constituting the recording layer (light absorbing layer) of the optical recording medium disclosed in 183296, the sensitivity required for the optical recording medium could not be obtained.

The medium described in JP-A-53-46019 and Example 2 is inferior in sensitivity and durability and required for an optical recording medium, in particular, 780-830 nm, which is necessary for a CD-WO.
Did not satisfy the condition of having a reflectance of 65% or more.

Japanese Patent Application Laid-Open No. 58-37851 describes the same configuration as the present invention, but as shown in the embodiments,
Reflectivity 30-51% and reflectance 6 required for CD-WO
It did not reach 5%, and the durability was not sufficient.

Further, as shown in JP-A-1-159842, when a medium is prepared using a general cyanine dye (for example, Japan Photosensitive Dye Laboratories, Photosensitive Dye Table (1969)), the sensitivity may be insufficient. And the reflectance was less than 65%.

The cyanine dyes described in the examples of EP 353394 and the phthalocyanine dyes described in the examples of EP 353393 have poor sensitivity and signal characteristics.
It was unsuitable as a dye for WO type optical recording media.

An object of the present invention is to provide a CD-WO type optical recording medium having a reflectance of 65% or more, which cannot be obtained in the above conventional example.

[0009]

Means for Solving the Problems The inventors of the present invention have made intensive studies to achieve the above object, and as a result, the melting point of the near-infrared absorbing agent contained in the recording layer of the CD-WO type optical recording medium was 150 ° C.
When the decomposition starting temperature is 200 to 350 ° C., the optical recording medium constituted by the recording layer containing the near-infrared absorbing agent has a signal writing sensitivity and a symmetric property of the written signal. It was found that the recording was good and the recording distortion was small.

Further, in a solution state (CCl ₄ ,
Using a near-infrared absorbing agent having a maximum absorption wavelength (λ _max ) of 670 to 720 nm in CHCl ₃ , toluene and the like for the recording layer, it has been found that the reflectance of the medium can be maintained at 65% or more, and the present invention has been achieved. In particular, it has been found that the introduction of a halogen atom or a specific substituent is effective with respect to the melting point and decomposition point of the used near infrared ray absorbent.

In the present invention, it has been found that the melting point and the decomposition point of the particularly used near-infrared absorbing agent greatly affect the sensitivity at the time of recording and the stability of reproduction, and based on these findings, the present invention has been completed. It is a thing.

The optical recording medium of the present invention has a configuration in which a recording layer, a metal reflection layer, and a protective layer are laminated in this order on a transparent substrate, and the recording layer has a melting point of 150 to 300 ° C. and starts decomposition. It is characterized by containing a near-infrared absorber composed of a compound having a temperature in the range of 200 to 350 ° C or a mixture thereof.

The melting point was measured with a commercially available melting point measuring instrument, and the decomposition point was measured with a simultaneous differential thermo-thermogravimetric analyzer (DTA-TGA).

The substrate used in the optical recording medium of the present invention may be an optically transparent resin. For example,
Examples include acrylic resin, polyethylene resin, vinyl chloride resin, vinylidene chloride resin, polycarbonate resin, ethylene resin, polyolefin copolymer resin, vinyl chloride copolymer resin, vinylidene chloride copolymer resin, and styrene copolymer resin. Further, the substrate may be subjected to a surface treatment with a thermosetting resin or an ultraviolet curable resin.

The near-infrared absorbing agent contained in the recording layer includes a compound group represented by the following formula (I):

[0016]

Embedded image [In the formula (I), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ ,
^{R 8, R 9, R 10} , R 11, R 12, R 13, R 14, R 15 and R
¹⁶ is independently a hydrogen atom, a halogen atom, a nitro group,
Represents a substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted alkoxyl group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkylthio group, substituted or unsubstituted arylthio group . However, R ¹ and R ⁴ , R ⁵ and R ⁸ , R ⁹ and R ¹² and R
In ¹³ the combination of R ^16, at least one, substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted alkylthio group, and from among substituted or unsubstituted aryl Le thio group Represents a selected group, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ ,
^{R 8, R 9, R 10} , R 11, R 12, R 13, R 14, R 15 and R
¹⁶ Of, 1-4 will display the halogen atom, Met 2
Hydrogen atoms, a divalent metal atom, a trivalent or tetravalent metal derivative. Among the phthalocyanine compounds and isomers represented by], melting point of a single or a mixture of 150
An optical recording medium having excellent recording sensitivity and recording characteristics can be obtained by selecting a dye or a dye mixture having a decomposition start temperature of 200 to 350 ° C. at a temperature of 300 ° C. to 300 ° C.

The CD-WO type optical recording medium of the present invention is a commercially available compact disc player or CD-ROM.
It is a reproducing apparatus, that is, a medium that can be read by a semiconductor laser of 760 to 800 nm. In order to improve sensitivity and reflectivity, that is, writing or reproducing performance, the maximum absorption wavelength (λ _max ) of the dye in chloroform is required.
Is preferably a dye or a dye mixture having a wavelength of 670 to 720 nm, and in particular, a molar extinction coefficient (ε _max ) at a maximum wavelength in a chloroform solution of 1 × 10 ⁵ l mol ⁻¹ c
It is preferably at least m ⁻¹ .

As a method for forming the recording layer, there is a method in which a single or a mixture of the above-mentioned compounds is applied or vapor-deposited in one or two layers, and the application method includes a binder resin of 20% by weight or less, preferably 0%. 0.05% by weight of previous compound
To 20% by weight, preferably 0.5% to 20% by weight in a solvent, followed by application by a spin coater. The vapor deposition method is 10 ⁻⁵ to 10 ⁻⁷ t.
There is a method of depositing the pre-compound on the substrate at orr, 100-300 ° C.

The thickness of the layer containing the near-infrared absorbing agent in the recording layer is preferably from 50 to 300 nm.

Solvents used for spin coating include halogenated hydrocarbons (eg, dichloromethane, chloroform, carbon tetrachloride, tetrachloroethylene, dichlorodifluoroethane, etc.) and ethers (eg, diethyl ether, dipropyl, etc.) depending on the solvent resistance of the substrate. Preferred are ethers, dibutyl ether, etc.), alcohols (eg, methanol, ethanol, propanol, etc.), cellosolves (eg, methyl cellosolve, ethyl cellosolve), and hydrocarbons (hexane, cyclohexane, octane, benzene, toluene).

The reflective layer is preferably made of aluminum, gold or the like, and the protective layer is preferably made of a transparent light-curable or thermosetting resin. The thickness is 1 to 100 n
m is preferred.

Further, as a method for producing the reflective layer, there are a vapor deposition method, a sputtering method and the like.

As a method of forming a protective layer, a recording layer is formed on a substrate as described above, and a UV curable resin or a thermosetting resin composition is applied by a spin coating method, a bar coater method, a dipping method, or the like. After that, there is a method of curing. Further, the thickness is preferably 1 μm to 500 μm.

When producing a CD-WO optical recording medium, it is preferable to use a polyacrylate substrate or a polycarbonate substrate and apply the substrate by spin coating from the viewpoints of cost and user handling.

[0025]

EXAMPLES The present invention will be described below in more detail with reference to examples, but embodiments of the present invention are not limited thereto. All parts in the examples are parts by weight.

Example 1 4,8,12,16-Tetrabromo-1,5,9,13-tetra (1,3-dimethylbutyloxy) phthalocyanine palladium (melting point 150-185 ° C., decomposition onset temperature 280 ° C., λ _max = 7
03 nm and ε _max = 1.6 × 10 ⁵ l mol ⁻¹ c
m ^-1 ) 1 part was dissolved in 200 parts of dibutyl ether and applied to a substrate for a polycarbonate CD-WO optical recording medium.
Gold was vapor-deposited thereon, and then overcoated with a photo-curable polyacrylic resin and photo-cured. The optical recording medium thus manufactured had a C / N ratio of 60 dB at a linear velocity of 1.4 m / sec and a laser power of 7 mW, and had good sensitivity. In addition, fade meter 63 ° C / 1
After irradiation for 00 hr, no deterioration of the recording layer was observed.

Example 2 10 parts of tetra (1,3-dimethylpropyloxy) phthalocyanine palladium was dissolved in 1000 parts of carbon tetrachloride, and
After 2 parts of bromine was added dropwise at 0 ° C. and reacted for 3 hours, the precipitated crystals were separated by filtration, washed and dried to obtain 5 parts of a dye mixture represented by the following formula.

[0028]

Embedded image

[0029]

Embedded image The melting point of this dye mixture was 170 to 200 ° C, and the decomposition starting temperature was 305 ° C.

5 parts of this mixture was dissolved in 500 parts of n-octane, and coated on a polycarbonate substrate for CD-WO with a dry film thickness of 150 nm by a spin coater. A 30 nm gold layer was sputtered thereon, and a UV-curable resin was coated and UV-cured to form a protective layer, thereby producing a CD-WO medium.

The CD-WO medium thus manufactured has a reflectivity of 65%, a linear velocity of 1.4 m / sec, a 7 mW,
Recording with a C / N ratio of 60 dB could be written with a 90 nm laser beam. Further, this recording medium did not change even in the light resistance test at 63 ° C. for 200 hours in a carbon arc lamp.

Example 3 10 parts of 1,5,9,13-tetra (2,4,4-trimethyl-3-hexyloxy) phthalocyanine palladium was dissolved in 1000 parts of acetic acid, and 10 parts of iodine was added. The mixture was reacted for 3 hours, and the precipitated crystals were separated by filtration and purified to obtain a mixture represented by the following structural formula.

[0033]

Embedded image (Melting point 200-245 ° C, decomposition onset temperature 285 ° C,
λ _max = 708 nm and ε _max = 1.5 × 10 ⁵ l
mol ^-1 cm ^-1 ) 5 parts of this dye mixture was dissolved in n-octane, and applied to a polycarbonate substrate for CD-WO by a spin coater. The film thickness was 120 nm. 50 nm of gold was vapor-deposited thereon, and then a protective layer was formed using a UV-curable resin.

The thus-produced CD-WO medium was recorded by a 780 nm laser with a linear velocity of 1.3 m / sec and 7 mW, and a C / N ratio of 55 dB was obtained.

When the medium was subjected to a light resistance test using a xenon lamp at 50 ° C., it was confirmed that there was no change even after 200 hours.

Embodiment 4

[0037]

Embedded image Phthalocyanine represented by the above formula (melting point: 165 to 200)
5 ° C., 300 parts of a 3: 1 mixture of dibutyl ether and diisopropyl ether, applied by a spin coater to a PMMA CD-WO substrate with a thickness of 120 nm, and then sputtered with 20 nm of gold. Finally, a protective layer was formed with a UV-curable resin to produce a recording medium.

The obtained medium has a linear velocity of 1.4 m / sec.
When recording with a 8 mW, 780 nm laser, C /
A record with an N ratio of 60 dB was obtained.

Example 5 A mixture of the following two compounds [(A) / (B) = 1/1]

[0040]

Embedded image

[0041]

Embedded image (The physical properties of this mixture are λ _max = 710 nm, ε _max = 1.7
× 10 ⁵ lmol ^-1 cm ^-1 , melting point 230-240
, And a decomposition start temperature of 270 ° C), and a CD-WO optical recording medium was prototyped in the same manner as in Example 1.

The obtained medium had a linear velocity of 1.4 m / sec.
When recording with a 6.5 mW, 780 nm laser,
A record with a C / N ratio of 55 dB was obtained.

Embodiment 6

[0044]

Embedded image Phthalocyanine represented by the above formula (melting point: 195 to 225)
° C., decomposition temperature _{253 ℃, λ m ax = 707nm} , ε max
= 2.0 × 10 ⁵ lmol ^-1 cm ^-1 ) 5 parts were dissolved in 300 parts of dibutyl ether, and the thickness was 150 nm on a polycarbonate CD-WO substrate by a spin coater.
Then, 30 nm of gold was sputtered, and finally a protective layer was formed with a UV-curable resin to produce a recording medium.

The obtained medium had a linear velocity of 1.3 m / sec.
When recording with a 8 mW, 780 nm laser, C /
A record with an N ratio of 60 dB was obtained.

Embodiment 7

[0047]

Embedded image Phthalocyanine represented by the above formula (λ _max = 694n
m, ε _max = 1.7 × 10 ⁵ l mol ⁻¹ cm ⁻¹ , melting point 250 ° C. or more, decomposition start temperature 309 ° C.) 5 parts were dissolved in chloroform 300 parts, and the surface was treated with an acrylic photopolymer. , Applied on the substrate on which the groove is formed,
Thereafter, an optical recording medium was produced in the same manner as in Example 6.

The obtained medium had a linear velocity of 1.4 m / sec.
When recording with a 7 mW, 780 nm laser, C /
A record with an N ratio of 55 dB was obtained.

Embodiment 8

[0050]

Embedded image Phthalocyanine represented by the above formula (λ _max = 708n
m, ε _max = 1.8 × 10 ⁵ l mol ⁻¹ cm ⁻¹ , melting point 262-286 ° C., decomposition start temperature 310 ° C.), and a CD-WO type optical recording medium was produced in the same manner as in Example 6. Produced.

The obtained medium had a linear velocity of 1.4 m / sec.
When recording with a 7 mW, 780 nm laser, C /
A record with an N ratio of 57 dB was obtained.

Embodiment 9

[0053]

Embedded imageThe phthalocyanine represented by the above formula (λ_max= 706n
m, ε_max= 1.8 × 10 ^Five l mol^-1 cm^-1, Fusion
Point 225-245 ° C, decomposition onset temperature 289 ° C)
Thus, a CD-WO optical recording medium was produced in the same manner as in Example 6.
Made.

The obtained medium had a linear velocity of 1.3 m / sec.
When recording with a 7 mW, 780 nm laser, C /
A record with an N ratio of 62 dB was obtained.

Embodiment 10

[0056]

Embedded image Phthalocyanine represented by the above formula (λ _max = 707n
m, ε _max = 1.9 × 10 ⁵ l mol ⁻¹ cm ⁻¹ , melting point 280-292 ° C., decomposition onset temperature 294 ° C.), and a CD-WO type optical recording medium was prepared in the same manner as in Example 6. Produced.

The obtained medium had a linear velocity of 1.4 m / sec.
When recording with a 7 mW, 780 nm laser, C /
A record with an N ratio of 61 dB was obtained.

Comparative Test The performance of the thus obtained CD-WO type optical recording medium of the present invention was compared with respect to an optical recording medium manufactured according to known requirements. The media prepared in Examples 2, 4 and 5 were used as the media of the present invention, and the media prepared according to the following seven known examples were used as comparative examples.

Comparative Example 1: An example in which the recording layer contains silver nitrate (see JP-A-58-37851) Comparative Example 2: An example using the following dye (JP-A-1-1598)
(See 42)

[0060]

Embedded image Comparative Example 3: Example of recording layer of inorganic compound (JP-A-53-46)
Comparative Example 4: Example using a copper-phthalocyanine dye (see JP-A-58-183296) Comparative Example 5: A medium was prepared in the same manner as in Example 1 using an example using a dye of the following formula:

[0061]

Embedded image However, the mp of the dye was 80 to 90 ° C., and the decomposition starting point was 310 ° C. Comparative Example 6: In the example using the following dye, a medium was produced in the same manner as in Example 1.

[0062]

Embedded image (The physical properties of the dye are as follows: melting point> 250 ° C., decomposition onset temperature 3
05 ° C. Comparative Example 7: Example using the following compound (EP035339)
3 was referenced. )

[0063]

Embedded image (The physical properties of this compound are as follows: melting point: 145 to 148 ° C., decomposition starting temperature: 210 ° C.) All of the above comparative examples were measured for physical properties according to the following procedures, and the results are shown in Table 1 in comparison with the examples.

The reflectance was measured at 780 nm with a linear velocity of 1.4 m / sec at 780 nm for the reflectance of 780 nm light. 1) The symmetry was 5% or less at a recording power of 5 to 90 mW. 5% or more (×), 2) pulse width correction is 4T signal (231 × 4 =
924 nsec), the required correction range is 0-
(〇) for 100 ns, -100 to -200 ns
ec (を), -200 nsec or more (×)
3) As for the recording distortion, the distortion of the recording waveform was measured with an oscilloscope, and the distortion of the gold layer was observed by observing the recording pit with a microscope. 4) The durability is 0.5 mW and the linear velocity is 10 m / sec at 10 m / sec.
The change in recording after ⁵ readings (reproducing light stability) and the change in recording by the accelerated sunlight fastness test using a xenon lamp at 40 ° C. for 100 hours were 10% or less (Δ), 1
0% to 20% was (△), and 20% or more was (X).

[0065]

[Table 1]

[0066]

[Table 2] * Measured by TG-DTA ** No data due to medium with inorganic compounds.

[0067]

According to the present invention, a recording layer, a metal reflection layer, and a protective layer are laminated in this order on a transparent substrate, and the recording layer has a melting point of 150 to 300 ° C. and a decomposition onset temperature of 200 to 350 ° C.
By using a dye having a λ _max of 670 to 720 nm, a highly durable CD-WO type optical recording medium with high sensitivity and small recording distortion can be obtained. The quality of this CD-WO type optical recording medium is stabilized as compared with the prior art.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shin Aihara 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemicals Co., Ltd. (56) References JP-A-58-36490 (JP, A) JP-A-58 37851 (JP, A) JP-A-2-206588 (JP, A) JP-A-2-502099 (JP, A)

Claims (3)

(57) [Claims] 1. A structure in which a recording layer, a metal reflection layer, and a protective layer are laminated in this order on a transparent substrate, wherein the recording layer has a melting point of 150 to 300 ° C. and a decomposition onset temperature of 200 to 300 ° C.
The following general formula (I) within the range of 300 ° C. [In the formula (I), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ ,
^{R 8, R 9, R 10} , R 11, R 12, R 13, R 14, R 15 and R
¹⁶ is independently a hydrogen atom, a halogen atom, a nitro group,
Represents a substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted alkoxyl group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkylthio group, substituted or unsubstituted arylthio group . However, R ¹ and R ⁴ , R ⁵ and R ⁸ , R ⁹ and R ¹² and R
In ¹³ the combination of R ^16, at least one is selected from among a substituted or unsubstituted alkoxyl group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted alkylthio group, and a substituted or unsubstituted arylthio group R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ ,
^{R 8, R 9, R 10} , R 11, R 12, R 13, R 14, R 15 and R
Of the ¹⁶ , ¹⁶ represent a halogen atom, and Met represents 2
Hydrogen atom, divalent metal atom, trivalent or tetravalent metal derivative. A compact disc-write-once (CD-W) comprising a phthalocyanine compound represented by the formula
O) type optical recording medium. 2. The optical recording medium according to claim 1, wherein the near-infrared absorbing agent has a maximum absorption wavelength in a chloroform solution of 670 to 720 nm. 3. The molar extinction coefficient at the maximum absorption wavelength of a near-infrared absorbing agent in a chloroform solution is 1 × 10 ⁵ l.
The optical recording medium according to claim 2, wherein the optical recording medium is at least mol ^-1 cm ^-1 .