JPH03296739A - Novel dyestuff recording material - Google Patents

Abstract

PURPOSE:To enhance contrast in reflectance and to improve suitability to reading by ensuring high reflectance owing to a lustrous layer of metallic Ag and a dyestuff-contg. layer and reducing the reflectance of recording pits from the reflectance before recording. CONSTITUTION:The reflectance of an optical recording material with a reflective lustrous layer of metallic Ag can freely be varied and can be controlled by varying the content of an Ag compd., heating time, compsn., etc. When the lustrous layer of metallic Ag is combined with a dye-contg. layer, an optical recording material having high reflectance can be produced. Such a recording material has high reflectance owing to a lustrous layer of metallic Ag formed by a reaction of an Ag compd. in the presence of developing nuclei of Ag or a nobler metal than Ag and a dye-contg. layer and the reflectance of recording pits is reduced from the reflectance before recording. Contrast ratio is increased at the time of reading, suitability to reading is improved and stable recording is enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides a new digital recording material suitable for writing and reading mainly with laser light.

(Prior Art) In recent years, laser-related technology has made remarkable progress, and as information becomes increasingly digitalized, various new optical recording materials necessary for this progress have been proposed.

An optical disc is a typical digital recording material. Optical disks using dyes have attracted attention and are being developed because they have the advantage of being inexpensive to manufacture. Furthermore, a write-once compact disk using a dye and having a high reflectance has been proposed, as disclosed in Japanese Patent Application Laid-Open No. 64-40388, and is attracting attention. Also,
Apart from this, a high-density optical card that can be carried around at all times has been proposed as a device that can be easily handled. Examples of this include JP-A-59-502139 and JP-A-58.
An optical card developed by Drexler, described in Japanese Patent No. 188346 and the like, is famous. Furthermore, various companies are developing optical card materials using materials similar to those used for optical disks. On the other hand, optical tape has been proposed as a material that is more compact than optical disks and can record a large amount of information.

Although a number of systems and materials have been proposed, such as writing sensitivity, storage stability of recording materials, recording density, error rate, and other characteristics necessary for recording materials are still insufficient. Therefore, the present inventors have developed a method for developing JP-A-2-743, which has excellent storage stability under high temperature and high humidity conditions and can be used satisfactorily as an optical recording material even under usage conditions such as bending.
A material having a metallic silver luster layer described in Publication No. 89 and the like was previously proposed.

(Problem H to be Solved by the Invention) The present invention provides an optical recording material that has a high reflectance, can obtain sufficient contrast, and has good reading characteristics. It also provides an optical recording material with good stability. The material of the present invention is of a coating type and can provide an inexpensive optical recording material.

(Means for solving the problem) An optical recording material that forms a reflective metallic silver luster layer by utilizing the reduction reaction of silver compounds caused by heating can freely change the reflectance from 20% to 90%. The reflectance can be controlled by changing the silver compound content, heating time, composition, etc.

By combining this metallic silver luster layer with a dye-containing layer, an optical recording material with high reflectance can be produced, and many functional improvements have been made. That is, the sensitivity was improved, the contrast ratio during reading was increased, the reading characteristics were also improved, and a stable recording material could be produced.

The optical recording material of the present invention has a high reflectance due to the contribution of the metallic silver luster layer formed by the reaction of a silver compound in the presence of silver or a metal more noble than silver and the layer containing the dye. The object of the present invention is to provide an optical recording material and a recording method thereof, in which the reflectance of pits to be recorded is lower than the reflectance before recording.

The reflective metallic silver gloss layer of the present invention is manufactured as follows. That is, metal development nuclei are formed on a layer containing a silver compound, a reducing agent, a binder, etc. (optical recording material composition layer) that has been applied in advance, and further under suitable heating conditions, for example, at a temperature of at least 70°C. When heated for several seconds to several minutes, a reflective metallic silver luster layer is formed on the surface layer. In order to form this reflective metal silver-containing layer, metal development nuclei that act catalytically are essential.

Silver compounds include organic silver salts and carboxylic acid silver-containing polymers. For example, it can be broadly divided into three types. ■Silver salts of long-chain fatty acids ■Silver compounds soluble in organic solvents ■Polymer containing silver carboxylate. As silver salts of long-chain fatty acids, silver salts of stearic acid, silver salts of behenic acid, and the like are particularly useful. However, other non-photosensitive silver salts such as silver saccharate, silver benzotriazole, etc. can also be used. As the organic solvent-soluble silver compound, those soluble in organic solvents are selected from among aliphatic carboxylic acid silver salts and silver metal chelate compounds. For example, as a preferable silver aliphatic carboxylate, a fluorine-containing silver aliphatic carboxylate is used, and as a silver metal chelate compound, for example, a fluorine-containing silver metal such as fluorine-containing β-diketones is used. Chelating agents are commonly used. Particularly preferred compounds include silver trifluoroacetate, silver hebutafluorobutyrate, silver perfluorooctanoate, silver trifluoromethanesulfonate, silver furoyl trifluoroacetonate, silver hexafluoroacetylacetonate, and silver hebutafluoroacetate. butanoyl pivanoyl methanate,
Examples include silver pivaloyl trifluoroacetonate, silver pivaloyl trifluoroacetonate, and silver furoyl trifluoroacetonate.

The silver carboxylic acid-containing polymer can be synthesized from a natural or synthetic polymer compound having a carboxylic acid in a polymer side chain. Among these, particularly useful silver carboxylate-containing polymers include silver salt compounds derived from natural products such as silver alginate and silver pectate, and silver compounds derived from synthetic polymers such as silver polyacrylate and silver methacrylate. You can choose from. Regarding synthetic polymers, copolymers with various monomers such as acrylic acid, methyl methacrylate, acrylonitrile, vinyl chloride, and vinyl acetate are particularly useful because they can be used as bases for silver-containing polymers.

Any reducing agent for the silver compound may be used as long as it can reduce the silver compound. however,
A reducing agent is not necessarily required for substances that self-reduce by heat or the like. Examples of preferred reducing agents include inhibiting phenols in which a sterically bulky group is bonded to the carbon adjacent to the carbon to which the hydroxyl group is bonded, sterically inhibiting the hydroxyl group, such as 2.6 -di-t-butyl-4-methylphenol, 2.2'-methylenebis-(4-methyl-6-t-butylphenol), 2°2°-methylenebis-(4-ethyl-6-t-butylphenol)
, 2,4.4-)listylpentylbis(2-hydroxy-3,5-dimethylphenyl)methane, 2.5-di-t-butyl-4-methoxyphenol, 2-t-butyl-6-( 3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenylacrylate, 4.
4”-Butylidene-bis-(3-methyl-6t-butylphenol, triethylene glycol-bis-[3-(
3-t-butyl-5-methyl 4-hydroxyphenyl)
propionate], 1,6-hexanethiol-bis-(3-(3゜5-di-butyl-4-hydroxyphenyl)propionate), 2,4-bis-(n-octylthio)-6-(4-hydroxy -3,5-di-t-butylanilino)-1,3,5-) riazine, pentaerythrityl-tetrakis-(3-(35-di-t-butyl-4-hydroxyphenyl)propionate), 2.2
-thio-diethylenebis(3-(3,5-di-L-butyl-4-hydroxyphenyl)propionate), octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2.2 -thiobis(4
-methyl-6-t-butylphenol), N.

No-hexamethylenebis(3,5-di-t-butyl-
4-hydroxy-hydrocinnamamide), 3,5-di-
t-Butyl-4-hydroxybenzylphosphonate diethyl ester, 1°3.5-) listyl-2,
4,6-)Lis(3゜5-di-t-butyl-4-hydroxybenzyl)benzene, bis(3,5-di-t-butyl-4-hydroxybenzylethyl)calcium, tris-(3 , 5-di-t-butyl-4-hydroxybenzyl)-isocyanurate, N.

No-bis[:3-(3,5-di-t-butyl-4-
Examples include hydroxyphenyl)propionyl]hydrazine. Also, reducing agents for silver salts such as hydroquinone, 2.5-dimethylhydroquinone, chlorohydroquinone, p-aminophenol, methylhydronaphthalene, phenidone, methyl gallate, p-phenyldenol, bisphenol A, 2,4-dihydroxy Benzoic acid, p-methoxyphenol can also be used. The amount of reducing agent varies depending on the type of reducing agent, etc., but for boat fishing, it is about 0.01 mol to 1 mol of silver compound.
About 10 moles, preferably about 0.1 moles to about 3 moles.

Preferred binders in the present invention include polymethyl methacrylate, polyvinyl formal, polyvinyl butyral, vinyl chloride-hinyl acetate copolymer, cellulose acetate, polystyrene, styrene-methyl methacrylate copolymer, styrene-butyl acrylate copolymer, styrene- It can be appropriately selected from a wide range of hydrophobic organic polymer compounds such as methyl methacrylate-methyl acrylate copolymer. This hydrophobic binder has a weight ratio of about 10 to the organic solvent-soluble silver compound.
The ratio is from 1:1 to about 1:10.

The metal development nucleus is silver or a metal species nobler than silver. Metals more noble than silver include palladium, platinum, gold,
Examples include rhodium, ruthenium, thallium, and mercury. These metal nuclei may be a single metal species, or may be a composite system or a compound such as silver sulfide or silver oxide.

The method for forming metal development nuclei on the surface of the optical recording material composition includes a method in which the metal development nuclei are dispersed in a solvent containing a suitable binder and coated on the surface of the optical recording material composition, or vapor deposition. It is also possible to form metal catalyst nuclei on the surface under gas phase conditions. Further, metal development nuclei made of the metal species itself may be formed on the surface by thickening the surface with a strong reducing agent or by exposing the surface to a reducing gas such as hydrogen gas for a short time. For example, typical manufacturing methods include a method in which the surface layer is sequentially immersed in an aqueous solution of stannous chloride and palladium chloride, and a metal nucleus is applied by electroless plating in which the metal nucleus of palladium is applied to the surface layer; Examples include methods for vacuum-depositing metals such as platinum, gold, silver, and palladium onto surfaces.

Further, a compound that forms silver sulfide nuclei, such as sodium sulfide, may be disposed on the surface layer. Alternatively, silver metal development nuclei may be provided on the surface by exposing the surface to a reducing gas such as hydrogen gas for a short time. It is necessary to select an appropriate forming method depending on the type of silver compound, binder, etc.

When an optical recording material composition layer having such a surface layer is heated under appropriate heating conditions, for example, at a temperature of at least 70°C for several seconds to several minutes, a reflective metallic silver-containing layer can be formed on the surface. can.

Appropriate heating conditions are preferably 90 to 160"C.
It takes about 2 to 100 seconds. These heating conditions must be controlled to optimal conditions in order to satisfy the structure of the present invention. In particular, care must be taken because excessive development tends to cause the reflective metallic silver-containing layer to become non-uniform.

The optical recording material of the present invention can contain various additive components to improve the intended performance of the material. For example, it is possible to introduce a compound that controls the size of silver particles in the metallic silver-containing layer. An example is a toning agent such as phthalazinone, which is used as a dry silver salt photosensitive material. Further, an anti-fogging agent, a sensitizer, etc. can be added as necessary.

The dye used in the present invention is a dye having a reflectance in the semiconductor laser wavelength range, and the semiconductor laser wavelength range here is 630 nm to 900 nm. What is important here is that the combination of the metallic silver luster layer and the dye layer improves the reflectance by 5% or more compared to the dye layer alone. Any dye can be used as long as it satisfies this condition. Furthermore, if there is no such improvement in reflectance, there will be no improvement in performance compared to an optical recording material with a dye layer alone.

Furthermore, when used in write-once compact discs, it is important that the combination of the metallic silver gloss layer and the dye layer has a reflectance of over 70%. Various dyes can be mentioned as dyes that can be used in the present invention, such as cyanine dyes, merocyanine dyes, styryl dyes, styrylquinoline dyes, phthalocyanine dyes, naphthalocyanine dyes, suaryllium dyes, and oxonol. You can select from among pigments such as xanthine pigments, triphenylmethane pigments, croconium pigments, azulenium pigments, naphthoquinone pigments, anthraquinone pigments, thiol nickel complex salts, hemicyanine pigments, logcyanine pigments, etc. can. Preferably, the dye has good light resistance to light in the semiconductor laser wavelength range, and the dye layer itself is reflective, such as cyanine dyes, phthalocyanine dyes, naphthalocyanine dyes, and 1,000-all nickel complex salts. , azulenium dyes, and the like. Specific examples will be given next, but the invention is not limited to these. 1,1゛-dimethyl-3,3,3
',3'-tetramethyl-4,5,4",5"-dihenzoindilipocyanine iodide, 1,1゜dibutyl-3,3,3',3'-tetramethyl-4,5,4
',5'-dibenzodicarbocyanine verchlorate,
1,1'-diethyl-3,3,3', 3'-tetramethyl-10-chloro-9,11-ethylene-4,5,4
',5''-dibenzoindodicarbocyanine perchlorate, 1,1'-dipropyl-3,3,3',3'-
Tetramethyl-5,5''-bis(l-phenyl-2-ethylene)dicarbocyanine toluenesulfonate, aluminum phthalocyanine, copper phthalocyanine, iron phthalocyanine, cobalt phthalocyanine, nickel phthalocyanine, titanium phthalocyanine, fluorinated aluminum phthalocyanine, magnesium phthalocyanine, Cobalt naphthalocyanine, nickel naphthalocyanine, titanium naphthalocyanine, magnesium naphthalocyanine, fluorinated alumina phthalocyanine, zinc phthalocyanine, ethylene 1,2
- dithiol-based nickel complexes and the like.

Various methods can be used to prepare the dye layer that comes into contact with the produced metallic silver gloss layer. It can also be coated onto the metallic silver gloss layer using a spin-coding method. The dye can be applied onto the metallic silver gloss layer using various coating techniques such as bar code method, reverse coating method, dip method, etc. Alternatively, the pigment may be applied on the transparent substrate using various methods, and then the metallic silver luster layer may be heat-adhered.
Adhesion may also be made through a very thin adhesive layer.

The reflectance referred to in the present invention is a value measured using the laser wavelength used for reproduction, and is 780nn+ when used for write-once compact discs, and usually 830new when used for other optical discs or optical cards. It is. High reflectance here refers to 35% or more.

The optical recording material of the present invention may be provided with a transparent protective layer for the purpose of protecting the recording layer. This protective layer is selected from highly transparent organic polymer compounds such as polycarbonate, polystyrene, polymethyl methacrylate, polyvinyl chloride, polyvinidene chloride, and polyethylene terephthalate. This protective layer may be used as a base for coating the recording layer.

In addition, even if the back side of the optical recording material consists only of a base film on which the optical recording layer is applied, there is also a reinforcing layer on the back side to prevent deterioration and scratches caused by bending and to protect from moisture. It's okay.

Further, the surface of the transparent protective layer is usually treated to make it less likely to be scratched.

The shape of the present invention may be card-like, disk-like, or tape-like.

The optical recording material of the present invention can be recorded with various laser light sources having appropriate power, typical examples being He--Ne laser and semiconductor laser.

For example, it is possible to write at a speed of about 1 m/s with a beam diameter of 1 μm using a semiconductor laser of about 5 mW.

The optical recording material of the present invention can be used as a so-called write-once type recording material, and the user can write on it as needed, and once written, it cannot be erased, so evidence is required. It can also be used for various purposes.

In addition, you can write information in advance to a read-only RO.
It can also be used as an M card.

Examples are described below to explain the present invention in more detail, but the present invention is not limited thereto.

Example 1 A solution consisting of the following components was prepared.

Silver trifluoroacetate 20g2.2-methylenebis(4-ethyl-6-t-butylphenol)
9g 2-butanone 200g methanol 1g toluene
60g polymethyl methacrylate
20 g of this solution was homogenized by stirring for about 1 hour and then passed through a filter with an average pore size of 1.5 μm.

This solution was dried on a polyethylene terephthalate film with a film thickness of 100 μm using a small blade coater, and then
Coating was carried out under conditions such that the thickness of the film was 10 μm.

Thereafter, it was dried at a temperature of 22° C. and a humidity of 50% RH. Thereafter, metal development nuclei, that is, palladium nuclei, were formed on the coated surface using a catalytic nucleation method for electroless plating manufactured by Nippon Schering Co., Ltd. as described above. The coated layer was sequentially immersed in the following aqueous solutions for 10 seconds each, then washed with water and air-dried.

(Aqueous solution 1) Activator Neogant 834 40111i! (Product name of Nippon Schering Co., Ltd.) Distilled water 956I11 Sodium hydroxide 3g (aqueous solution 2
) Reducer - Neogant WA 5ae (product name of Nippon Schering Co., Ltd.) Boric acid
5g distilled water 950id When the obtained sample was heated at 150°C for 400 seconds, silver was precipitated on the surface and a metallic silver luster layer was formed. Continued 1
．． 1'-Dimethyl-3,3,3", 3'-tetramethyl 4.5,4°, 5"-dibenzoindodicarbocyanine iodide (Japan Photosensitive Pigment Research Institute NK-2929) 0
．． A solution of 5 g dissolved in 13 cc of benzyl alcohol was applied onto the metallic silver gloss layer using a spin coater. Thereafter, a 1.2 mm thick polycarbonate plate was adhered onto this recording layer and a recording test was conducted. Here the wavelength is 780n*
When the reflectance was measured using a semiconductor laser, it was 75%.
Met. Recording speed 1m/s, recording power 4III
When the CN ratio was measured at W and a recording frequency of 100 kHz, a value of 52.5 dB was obtained. The reflectance of the recorded pit was 9
%Met.

Example 2 1st and 2nd thickness, in which a spiral pregroove with a width of 0.6 μm, a depth of 70 nm, and a pitch of 1.6 μm is formed.
1.1° on a polycarbonate base with an outer diameter of 120mmφ
-dipropyl-3,3,3',3'-tetramethyl5
．． A solution prepared by dissolving 0.6 g of 5'-bis(1-phenyl-2-ethylene)dicarbocyanine toluenesulfonate in 1 cc of dimethylformamide was applied using a spin cord method. The thickness of the dye layer was 10 na+. After that, palladium was vapor-deposited on the surface of the dye layer, and then the coating liquid shown below was applied so that the film thickness after drying was 6 μm.
Dry.

Silver trifluoroacetate 21g2.2-
Methylenebis(4,6-di-t-butylphenol)9
g 2-butanone 200g toluene 60g polystyrene
20g was then heated at 135°C for 400 seconds to prepare a sample. EFM the audio at a scanning speed of 1.1 m/s and a recording power of 6 s + W using a semiconductor laser beam with an emission wavelength of 780 nm on the sample.
The signal was modulated and recorded. I was able to play it using a commercially available compact disc player.

Assuming that the amplitude of the highest fundamental frequency (720 kHz) component of the (EFM high-frequency signal) is J and the highest level of the high-frequency signal is K, the reproduced waveform obtained by reproduction is 0.7 for I/, and J/
It was 0.45. Due to this, the compact disc standards (1/≧0.6, J/≧0.3-0.6
) is found to be satisfied. Also, 50℃, 90%
An acceleration test was conducted under the conditions of 20,000 lux irradiation with a halogen lamp under a constant temperature of 1,000 yen, but there was no change in the regeneration characteristics even after 1,000 hours.

It can be seen from Examples 1 and 2 that the present invention is effective.

(Effect of the invention) The present invention provides an 8-layer material with extremely high reflectance.
High contrast can be achieved, and playback can be performed stably. Furthermore, since it becomes possible to provide a write-once type compact disc having a recording layer having a dye and a metallic silver luster layer, it is very convenient because it can be played back using a commercially available compact disc player. Furthermore, by combining a metallic silver luster layer and a dye, it is possible to provide a highly sensitive and stable material and a recording method thereof.

Claims (3)

[Claims] (1) It has a high reflectance due to the contribution of a metallic silver luster layer formed by the reaction of a silver compound in the presence of silver or metal development nuclei nobler than silver and a layer containing a dye, and has a high reflectance for recording pits. An optical recording material whose reflectance is lower than the reflectance before recording. (2) The optical recording material according to claim (1), which has a reflectance of 70% or more before recording. (3) A method for recording information by irradiating the optical recording material according to any one of claims (1) and (2) with pulsed laser light.