JPH0440448A - High-sensitivity optical recording material - Google Patents

Abstract

PURPOSE:To enhance a recording sensitivity while having sufficient light resistance and reflectivity and to allow high-speed recording by dispersing the reflective metallic fine particles obtd. by reducing a org. silver chloride compd. and metallic compd. exclusive of silver into a hydrophobic binder. CONSTITUTION:The fine particles consisting of the silver and the metals exclusive of the silver are dispersed into the hydrophobic binder. The metallic fine particles may be the combination of the silver fine particles and the metallic fine particles exclusive of the silver and may be the composite fine particles of the silver and the metals exclusive of the silver in this case. The metallic fine particles may also be the combination of at least either of the silver fine particles and the metallic fine particles exclusive of the silver and the composite fine particles. An org. silver salt and silver carboxylate-contg. high polymer are usable as the silver compd. The optical recording material which allows the high-speed recording and has the excellent light resistance is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides a highly reliable and highly sensitive optical recording material capable of high-speed recording.

[Conventional technology]

In recent years, the density and capacity of digital recording materials have increased,
Along with this, various recording materials have been proposed. Among these, optical recording media that can be recorded and reproduced using lasers have been attracting attention as meeting these demands, and several types of recording media have been developed. Optical disks are a typical recording medium, but optical cards and optical tapes, which are easier to handle and carry, have been proposed.

Furthermore, write-once CDs that can be played on conventional CD players have also been proposed.

Previously, the present inventors developed an optical recording material consisting of fine silver particles/hydrophobic binder that has high sensitivity, high density, good stability under high temperature and high humidity conditions, and can be mass-produced by continuous coating, as disclosed in JP-A-2-74389.
It has been proposed in the bulletin etc.

However, when used as an optical card, it is usually taken outdoors without being placed in a protective jacket, so a recording material that is stable against strong light such as direct sunlight is required. Since the reflectance before recording was as high as 70% or more, it was difficult to increase the recording sensitivity. For the reasons mentioned above, it has been unavoidable to some extent that the recording sensitivity of the optical recording material used in such media is lower than that of optical disks, and as a result, the recording speed is slow. Therefore, in order to increase the recording speed, there is a need for a material that maintains stability against direct sunlight and reproduction light, or has even higher sensitivity while maintaining high reflectance.

[Problem to be solved by the invention]

The present invention provides an optical recording material that is capable of high-speed recording by having sufficient light resistance and high reflectance while increasing recording sensitivity. That is, the intensity of the laser light used for recording (usually 4 to 10 mW) is extremely short.
Recording is possible even with a pulse width of about 0.05 to 0.1 μs, and there is virtually no change in the recording and playback characteristics even when exposed to laser light or sunlight of the intensity used for playback (usually 1 mW or less) even after long periods of irradiation. A stable recording material can be provided.

Furthermore, the present invention aims to provide a highly sensitive optical recording material that can be mass-produced by continuous coating.

[Means for solving the problem] The present invention uses an organic silver salt compound and a metal compound other than silver as a precursor material for forming a reflective metal fine particle layer, so that the sensitivity can be adjusted to the intensity of the recording light. The object of the present invention is to provide an optical recording material that exhibits a sharp dependence on That is,
By changing the type and composition ratio of multiple metal compounds with different reactivity, the generation and growth rate of metal particles can be controlled, and as a result, the particle size distribution of the particles can be controlled, especially when composite particles of different metals are formed. It is possible to obtain a recording material that exhibits desired properties, such as being sharp and highly densely distributed. Regarding this, the present inventors have discovered that there is a relationship between the size of metal fine particles and their sensitivity to the recorded light intensity. , it is estimated that the sensitivity shows a sharp dependence on the recording light intensity. They have also discovered that by sharpening the particle size distribution and increasing the density of metal fine particles, a recording material with high reflectance and high sensitivity can be obtained.

That is, the present invention is an optical recording material in which fine particles of silver and a metal other than silver are dispersed in a hydrophobic binder. Here, the metal fine particles may be a combination of silver fine particles and metal fine particles other than silver, composite fine particles of silver and a metal other than silver, or a composite of at least one of silver fine particles and metal fine particles other than silver. It may also be in combination with fine particles.

In the present invention, organic silver salts and carboxylic acid silver-containing polymers can be used as the silver compound. These compounds can be roughly classified into the following three types. In other words, ■
These are silver salts of long-chain fatty acids, (1) organic solvent-soluble silver compounds, and (2) polymers 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.

Other non-photosensitive silver salts such as silver saccharate and silver benzotriazole can also be used. As the organic solvent-soluble silver compound, those soluble in organic solvents among aliphatic carboxylic acid silver salts and silver metal chelate compounds can be used. Preferably, the aliphatic silver carboxylate is a fluorine-containing silver aliphatic carboxylate, and the silver metal chelate compound is preferably a fluorine-containing silver chelate such as fluorine-containing β-digenes. -1- Other agents are generally used. Particularly preferred compounds include silver trifluoroacetate, silver hebutafluorobutyrate, silver perfluorooctanoate, silver dolifluoromethanesulfonate, silver furoyl trifluoroacetonate, silver hexafluoroacetylacetonate,
heptafluorobutanoyl biparoylmecne-silver complex,
Examples include silver pivaloyl trifluoroacetonate, silver 1-lifluoroacetylacetonate, and silver furoyl trifluoroacetonate.

Organic solvent-soluble silver compounds are those that dissolve at least 1 mg per ml of organic solvents used for boat fishing, such as alcohols, ketones, ethers, nitriles, halogens, aliphatic, aromatic, etc. is preferred.

A 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, silver salt compounds derived from natural products such as silver alginate and silver pectate, and silver compounds synthesized from synthetic polymers such as silver polyacrylate and silver methacrylate are useful. Regarding synthetic polymers, copolymers with various polymers 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. be.

In the present invention, compounds of transition metals from Groups 1 to 1B of the periodic table, such as gold, platinum, palladium, nickel, cobalt, and copper, are suitable as metal compounds other than silver.

These metal compounds may be any compounds as long as they can cause a reduction reaction with a reducing agent and supply metal atoms.

For example, gold compounds include gold(1) cyanide, potassium gold(III) cyanide, storium gold(1) chloride,
Gold(I) thiocyanate, gold(I) diosulfate, etc. can be used. As the platinum compound, potassium chloroplatinate (II), potassium chloroplatinate (TV), etc. can be used. As the palladium compound, palladium (II) acetate or the like can be used. As the nisogel compound, nickel acetate, nickel formate, nickel (II) acedelacetonate, nickel naphthenate, etc. can be used. Koharu 1~
The compounds include cobalt(II) acetate, cohal 1-(
II) Acetylacetonate, cobalt (III) acetylacetonate, cohal benzoate I-(II), cohal gluconate h (TI), cohal stearate I.
Cobalt phenyldiazulponate (■), cobalt naphthenate, etc. can be used. Hagiseicho as a copper compound,
Copper acetate, copper citrate (■), copper cyanide (I), copper gluconate (■), phthalate, copper thiocyanate, copper phenyldiazosulfonate (1), copper naphthenate, etc. can be used.

Moreover, complex salts of these metals can also be used depending on the purpose. For example, thiosulfur complexes and thiocyanate complexes of gold(1), bis(acetylacetonato)palladium(■), bis(glycinate) iliiJ
(n), bis(acetylacetonato)copper (■), hexaaminecohalt(III) chloride, acopentaaminecobalt(III) nitrate, thiocyanatopentaaminecobalt(III) sulfate, bromopentacyano Potassium cohal 1-(III) acids and the like can be mentioned.

In the present invention, the ratio of the silver compound to the metal compound other than silver is approximately 1 mol of the silver compound to 1 mol of the metal compound other than silver.
Xl0-6 mol to about 3 mol, more preferably about 1 x 10''3 mol to about 1 mol.

In the present invention, a recording layer made of irregular metal fine particles and a hydrophobic binder is formed as follows. That is, a silver compound, a metal compound other than silver, a reducing agent, and a polymer compound serving as a hydrophobic binder are dissolved in an organic solvent.
Alternatively, it can be uniformly dispersed and applied onto a base film. After drying the coating layer, catalytic nuclei are added to the surface of the coating layer, and by further heating this, a reduction reaction occurs between the silver compound and the metal compound other than silver, and the recording layer containing the reflective metal fine particle layer is formed. It is formed.

The thickness of this recording layer is about 1 to 25 μm. If it is thinner than this, sufficient metal compound cannot be supplied to form a reflective metal fine particle layer, and the surface smoothness is impaired due to the influence of the fine particles contained in the coating layer of the polyester film. Further, if the thickness is greater than this, the metal compound is wasted, leading to an increase in cost.

In the present invention, an appropriate reducing agent is required to form a reflective metal fine particle-containing layer.

Any reducing agent may be used as long as it can reduce silver compounds and metal compounds other than silver. 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-sheet t-butyl. -4-methylphenol, 2,
2'-methylenebis-(4-methyl-6-L-butylphenol), 2,2'-methylenebis-(4-ethyl-6L-butylphenol), 2,4.4-1-limethylpentylbis-(2- Hydroxy-3,5-dimethylphenyl)methane, 2,5-di-L-butyl-4-
Methoxyphenol, 2-t-butyl-6-(3'-
t-butyl-5'-methyl-2'-hydroxybenzyl)
-4-methylphenylacrylate, 4,4'butylidene-his-(3-methyl-6-t-butylphenol)
, triethylene glycol-bis(3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate), 1,6-hexanethiol bis-(3(
3+5-di-L-]thyl-4-hydroxyphenyl)propionate], 2,4-bis-(n-octylthio)
-6-(4-hydroxy-3,5-di-t-butylanilino)-1,35-1~riazine, pentaerythrityl-tetrakis(3-(3,5-di-butyl-4-hydroxyphenyl) Propione-11,2,2-thiodylenehis-C3-(3,5-di-butyl-4
-Hydroxyphenyl)propione-1-), 2.2-
Thiobis-(4-methyl-6-t-butylphenol)
, N,N'-hexamethylenebis-(35-di-butyl-4-hydroxy-hydrocinnamamide), 3.
5-di-L-butyl-4-hydroxy-henzylphosphonate-diethyl ester, L3,5-)Richleu2.4.6-)lis-(3,5-di-butyl-4-hydroxybenzyl)benzene, bis- (ethyl 3,5-butyl-4-hydroxybenzylbosponate)calcium, tris-(35-butyl-4-hydroxybenzyl)-isocyanurate, N,N'-bis-(3-(3 , 5-di-L-butyl-4-hydroxyphenyl)propionyl]hydrazine, etc. Hydroquinone, 2,5-dimethylhydroquinone, chlorohydroquinone, p-aminephenol,
Reducing agents for silver salts such as methylhydronaphthalene, phenidone, and methyl gallate, p-aminophenol, methylhydronaphthalene, phenyldenol, bisphenol A, 2,4-dihydroxybenzoic acid, and p-methoxyphenol can also be used. . The amount of the reducing agent depends on the type of reducing agent, but is generally about 0.01 mol to about 10 mol, preferably about 0.01 mol to 10 mol, preferably about 0.01 mol to 1 mol of the metal compound. ]~about 3
It is a mole.

A silver compound, a metal compound other than silver, and a reducing agent are usually dissolved or dispersed together with a polymer compound in a solvent to prepare a uniform coating solution, except when a polymer containing silver carboxylate is used. Examples of solvents include alcoholic solvents such as methanol, ethanol, isopropyl alcohol, and 2-ethylhexanol, 2-bucnon, acetone,
Organic solvents such as ketone solvents such as cyclohexanone, ester solvents such as ethyl acetate, aromatic hydrocarbon solvents such as toluene and xylene, and aliphatic hydrocarbon solvents such as n-hexane can be used.

Here, the selection of a polymer compound as a binder is not only important in producing a stable coating solution, but also
This is extremely important because it greatly affects the storage stability of the recording material obtained after coating, drying, and heating. In order to obtain better stability especially under storage conditions of high temperature and high humidity, use of hydrophilic binders such as gelatin and polyvinyl alcohol should be avoided. Preferred binders in the present invention can be appropriately selected from a wide range of hydrophobic organic polymer compounds such as polymethyl methacrylate, polyvinyl polymer, polyvinyl butyral, vinyl chloride-vinyl acetate copolymer, cellulose acetate, and polystyrene. The hydrophobic binder is in a weight ratio of about 10:1 to about 1:10 to the metal compound.

When using a silver carboxylate-containing polymer, the silver carboxylate-containing polymer is uniformly dissolved or dispersed in a solvent together with a metal compound other than silver and a reducing agent, coated on a suitable support, and dried. Alternatively, a silver carboxylate-containing polymer containing metal salts such as sodium, potassium, ammonium, and lithium may be uniformly dissolved.
After uniformly coating on an appropriate support and drying, a silver carboxylate-containing polymer may be prepared by supplying an appropriate soluble silver compound such as an aqueous silver nitrate solution to the coating layer.

The layer containing reflective metal particles of the present invention is formed as follows. That is, after drying a coating layer (recording material composition layer) containing a silver compound, a metal compound other than silver, a reducing agent, and a polymer compound in advance, metal development nuclei are formed on the surface, and when these are further heated, reflections occur on the surface area. A layer containing fine metal particles is formed. In order to form this reflective metal fine particle-containing layer, metal development nuclei serving as catalyst nuclei are essential.

As the metal development nucleus, metal species more sensitive than silver or silver can be used. Metals more harmful than silver include palladium, platinum, gold, rhodium, ruthenium, thallium, mercury, and the like. These metal nuclei may be a single metal species, a composite system of these metal species, or a compound such as silver sulfide or silver oxide.

The method for forming metal development nuclei on the surface of the recording material composition layer includes a method of dispersing the metal development nuclei in a solvent containing a suitable binder and coating the surface of the recording material composition layer, or a method such as vapor deposition. A method in which metal development nuclei are formed on the surface under gas phase conditions, a method in which a part of the silver compound is reduced by exposing the surface to a reducing solution or a reducing gas to form silver development nuclei, and electroless plating. Metal development nuclei such as palladium are formed by immersion in the activating solution used in the pretreatment of the method.
You can take the following methods. The most appropriate method can be selected depending on the type of metal compound, binder, etc.

When the recording material composition layer in which metal development nuclei are formed on the surface is heated under appropriate heating conditions, for example, at a temperature of at least 70°C for several minutes to several tens of minutes, a reflective metal fine particle-containing layer is formed on the surface. can be formed. Appropriate heating conditions are preferably 90 to 160°C for 50 seconds to
It takes about 15 minutes. In order to satisfy the characteristics of the recording material of the present invention, the heating conditions must be controlled to optimal conditions depending on the type of metal compound, reducing agent, and binder. In addition, care must be taken because if heating is insufficient, unreacted metal compounds may have an adverse effect on the storage stability of the recording material at high temperatures.

The optical recording material of the present invention can contain various additive components to improve the intended performance of the material. For example, a compound that controls the size of the metal fine particles in the metal fine particle-containing layer can be introduced.

Examples of this compound include toning agents such as fucladinone used in dry silver salt sensitizers.

Further, antifogging agents, sensitizers, etc. may be added as necessary.

Furthermore, in the present invention, it is possible to incorporate photosensitive silver halide into the recording material composition, and this combination facilitates preformat processing by performing back exposure through a roughening mask during manufacturing. You can also do this. Such a change in composition is achieved by applying a halogen ion source to a part of the organic solvent-soluble silver compound,
There is a method in which a part of the silver compound is converted into photosensitive silver halide in advance, and a method in which separately prepared silver halide microcrystals are dispersed in the recording material composition.

The optical recording material of the present invention is 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, polymethylmethacrylate-1, polyvinyl chloride, polyvinylidene chloride, and polyethylene terephthalate. Further, the back surface of the recording material layer may consist only of the base film, or may further include a reinforcing layer against bending, etc., on the back surface. Further, the surface of the transparent protective layer is usually treated to make it less susceptible to scratches and the like.

The optical recording material of the present invention may be in the form of a card, a disk, or a tape.

The optical recording material of the present invention is a He-N with suitable power.
Recording can be performed using various laser light sources including e laser and semiconductor laser. For example, wavelength 83
Using a semiconductor laser with a wavelength of 0 nm and an output of 10 mW,
Recording can be performed with a beam diameter of 2 to 3 μm and a pulse width of 0.1 to 0.05 μs.

The optical recording material of the present invention can be used as a so-called write-once type recording material, which allows the user to record as needed. can also be used. It can also be used as a read-only ROM card with preliminary information recorded thereon.

Examples of the present invention are shown below, but these are not intended to limit the present invention in any way.

Example 1 A coating liquid consisting of the following components was prepared.

Silver trifluoroacetate 4.0g Sodium gold(III) chloride 0.1g2-t
-butyl-6-(3'-t-butyl-5'methyl-2
4-Methylphenyl acrylate 1.4g polymethyl methacrylate
4.6g 2-butanone
23.0g toluene 7.
After homogenizing 7 g of this solution, it was passed through a filter with a pore size of 0.2 μm to remove undissolved substances and dust. This coating liquid was applied to a polyester film using an applicator so that the thickness after drying was 12 μm, and dried to form a recording material composition layer.

Next, this was sequentially immersed in the following electroless plating pretreatment solutions 1 to 4 for the times shown below and dried to form physical development nuclei of palladium on the surface of the recording material composition layer.

[Treatment liquid 1] ...30 seconds Aczihater Neogan l-8348ml (manufactured by Nippon Schering) Sodium hydroxide 0.6g Pure water
988 ml [Processing liquid 2
] ... 5 seconds Pure water 1 ta [Processing liquid 3
]...30 seconds reducer neogan 1-WA 1 rM
(Made by Nippon Schering) Boric acid 1g pure water
990 ml [Processing liquid 4] ・
...5 seconds pure water II! .

Next, the sample was heated at 150° C. for 15 minutes to form a reflective layer containing fine metal particles on the surface.

The reflectance of this recording material was 62χ. In addition, a semiconductor laser with a wavelength of 830 r++n (power 10 mW
, beam diameter 3 μm), recording and reproducing tests were performed at scanning speeds of 40 c:n/sec and 2 m/sec, and the C/N
The ratio was measured. The results are shown in Table 1. Further, as a light resistance test, this recording material was left for 500 hours under the condition of illuminance of 20,000 lux using a white fluorescent lamp, and then similar recording and reproducing characteristics were evaluated, and the results shown in Table 1 were obtained.

Comparative example 1 A coating liquid consisting of the following components was prepared.

1-silver fluoroacetate 4.0g2-
t-Butyl-6-(3'-1-butyl-5'methyl-
21-hydroxyhensyl) 4-methylphenylacrylate 1.4g polymethyl methacrylate 4.6g 2-butanone 23.0g toluene
A recording material was produced in the same manner as in Example 1, except that the above solution was used as a 7.7 g coating solution. The reflectance of this recording material was 61%. This recording material was subjected to the same recording/reproducing characteristics and light resistance tests as in Example 1. The results are shown in Table 1.

Table 1 Example 2 A solution consisting of the following components was prepared as a coating liquid.

Silver Hebutafluorobutyrate 5.0g Bis(
acetylacetonato) Copper (II) 0.5 g 2-t-butyl-6-(3'-t~butyl-5'methyl-2'-hydroxyhensyl) 4-methylphenylacrylate 1.4 g Hydroquinone 0.2 g styrene/
Methyl methacrylate/methyl acrylate copolymer polymer 4.6g Methyl ethyl ketone 23.0g/Luene
After homogenizing 7.7 g of this solution, it was passed through a filter with a pore size of 0.2 μm to remove undissolved substances and dust. This coating liquid was applied to a polyester film using an applicator so that the thickness after drying would be 8 μm, and dried to form a recording material composition layer.

Next, this was sequentially immersed in the following electroless plating pretreatment solutions 1 to 4 for the times shown below and dried to form physical development nuclei of palladium on the surface of the recording material composition layer.

[Treatment liquid 1]...30 seconds Aktiheku Neogant 834 8 ml.

(Made by Nippon Schering) Thorium hydroxide 0.6g Pure water
988 nil [Processing liquid 2
] ・・・5 seconds Pure water 1℃ [Processing liquid 3
] ...30 seconds Reso User Neo Gun 1-WA 1 m!
(Made by Roki Schering) Boric acid 1g pure water
990 mfl [Treatment liquid 4]
...Pure water for 5 seconds 12 Next, this sample was heated at 150° C. for 15 minutes to form a reflective metal particle-containing layer on the surface to produce a recording material. Next, this material was placed on a polycarbonate substrate for compact discs with groups attached, and heated in a heat press machine for 12 seconds.
A disc-shaped sample was produced by pressing at a temperature of 0°C and a pressure of 5 kg/- for 10 minutes. The reflectance of this sample was 74χ.

After recording a signal with a laser pulse width of 0.08 μs using a disc recording device, this disc could be played back using a playback-only compact disc player. Further, as light resistance test 1~, this recording material could be played back on a compact disc player even after being left for 500 hours under the condition of illuminance of 20,000 lux using a white fluorescent lamp.

Comparative example 2 A solution consisting of the following components was prepared as a coating liquid.

Silver Hebutafluorobutyrate 5.5g2-t
-butyl-6-(3'-1-butyl-5'methyl-2
'-Hydroxyhensyl) 4-methylphenylacrylate 1.4g Styrene/methylmethacrylate-1-/methylacrylate copolymer 4.6g medyl edyl ketone 23.0 g toluene
A disk-shaped sample was prepared in the same manner as in Example 2, except that the above solution was used as a 7.7 g coating liquid. The reflectance of this sample was 75χ. When this disc was recorded with a signal using a laser pulse width of 0.08 μs using a disc recording device and played back using a compact disc player, a sufficient playback signal could not be obtained. However, when a signal was recorded using a pulse width of 0.5 μs, , it was reproducible (it was reproducible).

〔Effect of the invention〕

As can be seen from the Examples and Comparative Examples, it was possible to obtain a highly reliable optical recording material that was capable of high-speed recording and had excellent light resistance.

Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] An optical recording material in which reflective metal fine particles obtained by reducing an organic silver salt compound and a metal compound other than silver are dispersed in a hydrophobic binder.