JPS62124988A - Optical recording medium - Google Patents

Abstract

PURPOSE:To obtain an optical recording medium capable of recording with favorable contrast and having excellent light resistance and resistance to reproducing light, by providing a recording layer comprissing a naphtholactam light- absorbing coloring matter having a specified chemical structure. CONSTITUTION:A recording layer comprising a naphtholactam light-absorbing coloring matter of formula (I), wherein L is a subst. or unsubst. aromatic amine residue, R is a subst. or unsubst. alkyl, cycloalkyl, aryl or allyl, Z<-> is an anion, and ring A is a naphthalene ring which may have a substituent, is provided on a base to produce this optical recording medium. The recording layer may be provided by a thin film forming method such as a sputtering method, a doctor blade method, a casting method, a spinner method and a dipping method. When forming the recording layer by the spinner method, a coating solvent is used. When a laser beam is focused on the recording layer provided on the base, the part irradiated with the laser beam of the recording layer undergoes a thermal deformation such as decomposition, evaporation and melting, whereby information is recorded.

Description

[Detailed description of the invention] (a) Purpose of the invention The present invention relates to optical recording media.

(Industrial Application Field) The optical recording medium of the present invention can be advantageously used as a recording medium for high-density information recording and storage using laser light and the like, and for recording and reproducing the same.

(Prior Art) Optical recording using laser light or the like allows information to be recorded and stored at high density, and the recorded information can be easily reproduced and used. An example thereof is an optical disk.

In general, optical discs are provided on a circular base and a thin recording layer is irradiated with a laser beam focused to a thickness of about 1 μm to record high-density information.

The recording is performed by thermal deformation such as decomposition, evaporation, melting, etc. occurring in the recording layer at that location due to absorption of the irradiated constant laser light energy. Furthermore, reproduction of the recorded information is performed by reading the difference in reflectance between a portion where deformation has occurred and a portion where deformation has not occurred by laser light. .

Therefore, as an optical recording medium, it is necessary to have high absorption of laser light, and in order to accurately reproduce information, it must have a high reflectance to laser light of a specific wavelength used for reproduction.

Various configurations of this type of optical recording medium are known. For example, Japanese Patent Application Laid-open No. 55-97033 discloses a 7T product in which a single layer of a 7 thalocyanine dye is provided on a substrate. Phthalocyanine dyes have drawbacks such as low sensitivity, high decomposition point and difficulty in vapor deposition, and extremely low solubility in organic solvents, making it difficult to coat them to form a recording layer.

JP-A-58-83344 discloses nine recording layers in which a phenalene dye is provided, and JP-A-58-224793 discloses nine recording layers in which a naphthoquinone dye is provided in the recording layer. Although such dyes have the advantage of being easy to vapor deposit, they have the disadvantage of low reflectance. If the reflectance is low, the laser beam will reduce the contrast in reflectance between the exposed portion of the recording layer and the unrecorded portion, making it difficult to reproduce recorded information.

Also, JP-A-59-24692, JP-A-59-6
No. 7092 and Japanese Patent Application Laid-open No. 71895/1989,
A recording layer in which a cyanine dye is provided in the recording layer is disclosed. Such dyes have the advantage of being easy to coat, but have the disadvantage of poor light resistance and deterioration due to reproduction light.

(Problems to be solved by the invention) In the present invention, the recording layer itself can be easily formed by coating,
The object of the present invention is to provide an optical recording medium in which the recording layer has a high reflectance and good recording contrast, and is also excellent in light resistance and resistance to reproduction light.

(b) Structure of the Invention (Means for Solving the Problems) As a result of repeated research in order to solve the above-mentioned problems, the present inventors have developed a method that contains a naphtholactam light-absorbing dye having a specific chemical structure. By providing a recording layer for recording, this purpose could be easily achieved.

That is, the optical recording medium of the present invention has a substrate having a general formula: or represents an allyl group, Z-
represents an anion, and 3JA represents a naphthalene ring which may have a substituent. ) It is characterized in that it is provided in a recording layer containing a naphtholactam light-absorbing dye represented by:

an alkyl group represented by R in the general formula (I),
Examples of substituents or substituent atoms of cycloalkyl groups, aryl groups, or allyl groups include alkoxy groups, alkoxyalkoxy groups, alkoxyalkoxyalkoxy groups, allyloxy groups, aryl groups, aryloxy groups,
Examples include a cyano group, a hydroxy group, a tetrahydrofuryl group, and a halogen atom.

7'j, as the substituent or substituent atom of the naphthalene ring represented by ring A, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an algylamino group, an acylamino group, an amino group and nonionic groups such as hydroxyl groups.

Furthermore, examples of the substituted or unsubstituted aromatic amine residue represented by L include tetrahydroquinolines,
or the general formula (wherein X and Y are each a hydrogen atom, a halogen atom,
Represents an alkyl group, an acylamino group or an alkoxy group. R2 and R3 each have a hydrogen atom and a carbon number of 1 to 20
represents a substituted or unsubstituted alkyl group, aryl group or cyclohexyl group, and substituents for the alkyl group, aryl group or cyclohexyl group include, for example, an alkoxy group, an alkoxyalkoxy group, an alkoxyalkoxyalkoxy group, an allyloxy group, an aryl group. , aryloxy group, cyano group, hydroxy group, tetrahydrofuryl group, etc. ).

′! ! As an anion represented by 2-, an example is ■-5Br-1cL-1cto4-1BF4-5SC
Examples include N-1.

The naphtolactam color table represented by the general formula (I) has absorption in the wavelength band of 600 to 800 nm, and has a molecular absorption coefficient of 104 to 105 crIK-1.

Among the naphtholactam dyes represented by the general formula (1), preferred are the general formula (wherein X and Y each represent a hydrogen atom, a halogen atom, an alkyl group, an acylamino group, or an alkoxy group, and R is Represents a substituted or unsubstituted alkyl group, cycloalkyl group, aryl group or allyl group, R2 and R3 are each a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms,
represents an aryl group, 7lyl group or cycloalkyl group,
R4 and R5 each represent a hydrogen atom, a halodane atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylamino group, an acylamino group, an amino group, or a hydroxy group, and 2- is an anion. represents. Examples of substituents for the alkyl group, aryl group, or cycloalkyl group include an alkoxy group, an allyloxy group, an aryl group, an aryloxy group, a cyano group, a hydroxy group, or a tetrahydrofurfuryl group. )
There are things expressed by ゛.

The naphtholactam dye represented by the general formula (It) is described in known literature (for example, British Patent No. 1,055,831).
The general formula obtained using the t reaction described in the specification of the Japanese Patent Publication No. 41-2905, etc.) [wherein R1, R4, R5, and Z -u are the same as those in the general formula (II) above] It is. ] A compound represented by the general formula [wherein X, Y, R2, and R5 are the above general formula (It)
are the same as those in . ] It can be easily produced by carrying out a condensation reaction with an aromatic aldehyde represented by the following.

The optical recording medium of the present invention basically consists of a substrate and a recording layer, but if necessary, an undercoat layer may be further provided on the substrate and a protective layer gold film may be provided on the recording layer. can.

The substrate in the present invention may be either transparent or opaque to the laser beam used. As the material for the substrate, supports for this type of recording medium, such as glass, plastic, paper, plate-shaped or foil-shaped metal, can be used, but glass is preferred from various points of view. Examples of such plastics include acrylic resin,
Examples include methacrylic resin, vinyl acetate resin, vinyl chloride resin, nitrocellulose, polyethylene resin, polypropylene resin, polycarbonate resin, polyimide resin, and polysulfone resin.

The thickness of the recording layer containing the naphtholactam light-absorbing dye as the information recording layer in the optical recording medium of the present invention is 10
01-5 μm, preferably 500×-3 μm.

To form the recording layer, a commonly used thin film forming method such as a starburst method, a doctor blade method, a casting method, a spinner method, or a dipping method is used. The recording layer can be formed by using a naphtholactam light-absorbing dye in combination with a binder.

So (D binder and L-Oj:,,+e libinilua#
:Resins such as r-ru, polyvinylpyrrolidone, nitrocellulose, cellulose acetate, polyvinyl butyral, and polycarnate are used. The content of the naphtholactam light-absorbing dye in the recording layer is desirably 1 weight percent or more relative to the resin.

The above-mentioned doctor blade method, cast method, spinner method,
When forming a recording layer by a coating method such as a dipping method, especially a spinner method, a coating solvent is used, such as bromoform, dibromoethane, tetrachloroethane, ethyl cellosolve, xylene, chlorobenzene, and cyclohexanone. Solvents having a boiling point of 120 to 160°C are preferably used. In the case of film formation by the spinner method, the rotation speed is preferably 500 to 5000 rpm, and after the spin code, all treatments such as heating or exposure to solvent vapor may be performed as the case requires.

In the recording layer of the optical recording medium of the present invention, transition metal chelate compounds (such as acetylacetonate chelate, bisphenyldithiol, salicyl aldehyde oxide, bisdithiol-α-nogatone, etc.)
may be contained.

Furthermore, all other dyes can be used in combination in the recording layer of the present invention. Examples of other dyes include indophenol dyes, triarylmethane dyes, azo dyes, cyanine dyes, squalirium dyes, and the like.

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

Recording on the optical recording medium of the present invention is carried out by applying laser light, preferably semiconductor laser light, focused to about 1 μm onto the recording layer provided on both sides or one side of the substrate. In the area irradiated with the laser beam, thermal deformation of the recording layer such as decomposition, evaporation, and melting occurs due to absorption of the laser beam energy, and information is recorded.

The recorded m information is reproduced by using a laser beam and reading the entire difference in reflectance between a portion where thermal deformation has not occurred and a portion where no thermal deformation has occurred.

The laser used for recording and reproducing the optical recording medium of the present invention includes N2, Hs'-Cd 1Ar %He
-No., ruby, semiconductor, dye lasers, etc., but semiconductor lasers are particularly preferred from the viewpoint of lightness, ease of handling, compactness, etc.

(Example) The present invention will be described in more detail below with reference to Examples.

Example 1 Synthesis of naphtholactam dye: Compound represented by the structural formula 39.0,9. and a compound represented by the structural formula H3 19.1.9t-1 glacial acetic acid 250.
! Add to i+ and 50g of acetic anhydride and heat to 100-105℃
The mixture was stirred for 4 hours to react, and after the reaction was completed, it was cooled to room temperature.

This reaction product liquid was mixed with sodium perchlorate 16. Poured into 1.51 liters of water containing OI and stirred at room temperature for 8 hours. The precipitated crystals tF were collected and dried to obtain a naphtholactam pigment of black-green crystals having the following structural formula 45. ! i'ffi got it. λtllll of this dye in solution (chloroform)
ILX is 740 nm.ft-0r Optical recording medium: 1 g of naphtho2cutam dye obtained as above
A solution obtained by dissolving in ethylcellosorg and filtering through a 0.22μ filter. [2'1lJt-1 depth 700^,
It was dropped onto a polycarbonate resin substrate (130 wφ) with grooves (groups) having a width of 0.7 μm, and was applied at a rotation speed of 800 rpm. After coating, it was dried at 60°C for 20 minutes. Separately, to measure the film thickness, the film was coated on a glass plate under the same conditions and the film thickness was measured by Talystep, and the film thickness was 650X. The maximum absorption wavelength of the coating film was 790 nm, and the peak width was wide.

This coating film was coated with a semiconductor laser beam with a center wavelength of 830 nm, an output of 6 mW, and a beam diameter of 1? When irradiated with Mμ, a very clearly defined hole (pit) with a width of about 1 μm and a bit size of 2 μm was formed. The career level/
The noise level ratio (C/N ratio) was ld52 dB. Moreover, the light resistance of the coating film and the resistance to reproduction light were good.

Example 2 According to the synthesis method of Example 1, a naphtholactam dye having the following structural formula was synthesized. λmax (
chloroform solution) was 740 am.

This naphtolactam dye II! and nitrocellulose (Daicel Chemical Co., Ltd. trade name R3-20) 1.5.9 were dissolved in ethyl cellosolve 50.9 and filtered through a 0.22μ filter to obtain a solution. 3rnl of this solution was dropped onto a polycarbonate resin substrate (120+mφ) with grooves (groups) with a depth of 650X and a width of 0.7μ.
Coating was carried out at a rotation speed of 0 rpm. After coating, 10 at 60℃
Dry for a minute. To measure the film thickness, the film was coated on a glass plate under the same conditions and measured using a Talisteg, and the film thickness was 700X.

The maximum absorption wavelength of the coating film was 790 nm, and the peak width was wide.

When this coating film was irradiated with semiconductor laser light with a center wavelength of 830 nm and a beam diameter of 1 μm at an output of 6 mW,
A very clearly defined hole with a width of about 1 μm and a pit size of 2 μm was formed. t'ft:,, Its carrier level/noise level ratio id was 51 dB, and the light resistance and resistance to reproduction light were good. Example 3 According to the synthesis method of Example 1, the following structural formula was synthesized. We synthesized a naphtholactam dye with the following properties. λmax (
chloroform solution) was 740 nH.

This naphtolactam dye II gold diglomoethane 50.
F and filtered through a 0.22μ filter to obtain a solution. This solution 2 was dropped onto a methyl methacrylate resin substrate (120 nmφ) with grooves (groups) made of ultraviolet curable resin with a depth of 700× and a width of 0.7 μ, and applied by a spinner method at a rotation speed of Q1200 rpm. ℃
Let dry for 10 minutes. When coated on a glass plate under the same conditions and measured the coating film thickness using Talystep, it was found that 700X
Met. The maximum absorption wavelength of the coating film was 790 nm, and the shape of the spectrum was wide.

When this coating film was irradiated with semiconductor laser light with a center wavelength of 830 nm at an output of 6 mW and a beam width of about 1 μm, extremely clear holes (bits) with a width of about 1 μm and a pit diameter of 2 μm were formed. Its C/N ratio is 48 dB
The light resistance and resistance to reproduction light were good.

Examples 4 to 87 Various naphtholactam dyes shown in Table 1 were synthesized according to the synthesis method of Example 1. λmli of this dye! (chloroform solution) and the maximum absorption wavelength of the coating film coated on the polycargonate a-fat substrate according to the method of Example 1 is shown in Table 1 and is 7t.

Unfortunately, when the coating film was irradiated with semiconductor laser light with a center wavelength of 830 nm, holes (pits) with extremely clear outlines were formed, indicating that the film had a high reflectance, high sensitivity, and an excellent C/N ratio. However, the light resistance and resistance to reproduction light were good.

(C) Effects of the Invention In the optical recording medium of the present invention, the naphtholactam light-absorbing dye for forming the recording layer has excellent solubility in organic solvents, so the recording layer itself can be easily formed by coating. It has high reflectance and good contrast, and is also resistant to light and reproduction light.

Claims (1)

[Claims] 1) The substrate has a general formula ▲a mathematical formula, a chemical formula, a table, etc.▼ (In the formula, L represents a substituted or unsubstituted aromatic amine residue, and R represents a substituted or unsubstituted alkyl group, cycloalkyl group, aryl group or allyl group, Z^
- represents an anion, and ring A represents a naphthalene ring which may have a substituent. ) An optical recording medium comprising a recording layer containing a naphtholactam light-absorbing dye represented by: 2) The naphtholactam light-absorbing dye has a general formula ▲ mathematical formula, chemical formula, table, etc. ▼ (in the formula, X and Y are a hydrogen atom, a halogen atom,
It represents an alkyl group, an acylamino group or an alkoxy group, R^1 represents a substituted or unsubstituted alkyl group, cycloalkyl group, aryl group or allyl group, and R^2 and R^3 each represent a hydrogen atom and a carbon number of 1 ~20 substituted or unsubstituted alkyl groups, aryl groups, allyl groups, or cycloalkyl groups, and R^4 and R^5 are each a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, or a cycloalkyl group having 1 to 10 carbon atoms. ~10 represents an alkoxy group, alkylamino group, acylamino group, amino group or hydroxy group, and Z^- represents an anion. ) The optical recording medium according to claim 1, which is a naphtholactam dye represented by: