JPH03258589A - Manufacture of optical recording material - Google Patents

Abstract

PURPOSE:To make it possible to manufacture a flawless and highly reliable recording material simply and at low cost by forming a metal catalytic nucleus on a specified transparent substrate without any change in reflection factor, then forming and heating a silver salt compound with the formation of a metal silver particle-dispersed layer on a substrate surface side and increasing the reflection factor to 10 to 90% through the transparent substrate. CONSTITUTION:In the manufacture of an optical recording material which consists of a reflective recording layer composed of metal silver particles dispersed in a hydrophobic binder, laminated on a transparent substrate, and regenerates a recorded information optically through the transparent substrate, a metal catalytic nucleus of silver or a nobler metal than silver is formed on the transparent substrate having 85% or higher transmissivity of light for record regeneration and 100nm or lower double refraction in double pass without any substantial change in reflection factor. Next, a silver salt compound containing an organic silver oxidizing agent, a reduction agent and a hydrophobic binder is formed. Then a metal silver particle-dispersed layer is densely formed on the substrate side of the silver salt compound by heating the compound at 100 to 200 deg.C. After that, an optical recording material is manufactured so that th reflection factor becomes 10 to 90% through the transparent substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing an optical recording material that utilizes the change in reflectance caused by laser light.

[Conventional technology]

BACKGROUND ART In recent years, laser-related technology has made remarkable progress, information has become increasingly digitalized, and various new optical recording materials necessary for this have been proposed.

An optical disc is a typical digital recording material. Optical discs are compact discs (CDs)
), write-once optical discs that can be recorded only once, rewritable optical discs that can be recorded many times, etc.

Apart from this, an optical card material has been proposed that has high density and can be carried at any time as a material that can be easily handled.

A well-known example of this is the optical card developed by Drexler, which is described in JP-A-59-501239 and JP-A-58-188346. Furthermore, optical cards are being developed by various companies using materials similar to those used for optical disks.

These optical recording materials usually have a laminated structure consisting of an optical recording layer and an optically transparent substrate or protective layer.
By performing optical recording and reproducing through these substrates, we provide highly reliable optical recording materials that protect the optical recording layer and are resistant to scratches and scratches.

On the other hand, the present applicants have proposed a new optical recording material having a reflective layer consisting of metallic silver particles and a hydrophobic binder substance. This recording material has excellent storage stability under high temperature and high humidity conditions, can be used satisfactorily as a recording material even under severe usage conditions such as bending, and is a low-cost optical recording material. There is a method of laminating this reflective recording material and a transparent substrate or a transparent protective layer using an adhesive, but defects such as dust and air bubbles are likely to occur on the surface of the reflective recording material during adhesion, making it difficult to use as a recording material. reduce reliability. Further, in the case of a transparent substrate having grooves, since the grooves of the grooves are minute, it is difficult to completely bring the reflective recording material into close contact with the transparent substrate, and standard products cannot be used, which is also disadvantageous from an industrial perspective.

[Problem to be solved by the invention]

In an optical recording material in which a reflective recording layer in which fine metal silver particles are dispersed in a hydrophobic binder and a transparent substrate are laminated, and recording and reproduction are performed optically through the transparent substrate, there is no dust or dirt on the recording surface. It is extremely important industrially to provide a method for producing highly reliable recording materials that are free from defects such as voids.

[Means to solve the problem]

As a result of various studies conducted by the present inventors, we discovered that a reflective recording layer in which metallic silver particles are dispersed in a hydrophobic binder and a transparent substrate are laminated, and recording and reproduction can be optically performed via the transparent substrate. In the method for manufacturing optical recording materials, the transmittance of recording and reproducing light is 85% or more, and the birefringence is 11% in double pass.
Silver or a metal catalyst nucleus nobler than silver is formed on the substrate having a particle diameter of 00n or less without a substantial change in reflectance, and then a silver salt composition containing an organic silver salt oxidizing agent, a reducing agent, and a hydrophobic binder is applied. Then, by heating to 100 to 200'C, a metal silver particle dispersed layer is formed densely on the substrate surface side of the silver salt composition, and the reflectance through the transparent substrate is 10 to 90.
%, and further relates to a method for producing an optical recording material in which a transparent substrate has grooves provided in advance.

More preferably, after forming the silver salt composition, the illuminance is 1
This method of producing an optical recording material is characterized by drying at 50-80'C in a dark place of 0 lux or less and then heating at 100-200'C.

The transparent substrate used in the present invention may be any material as long as it has a transmittance of recording and reproducing light of 85% or more and a birefringence of 1100 nm or less in double pass. For example, glass or plastics such as polymethyl methacrylate, polycarbonate, and epoxy resin can be used as the material. size, shape,
Although the thickness is not particularly limited, if the birefringence is large, the photodetector will not function properly during optical recording and reproduction, so it is necessary that the transparent substrate has birefringence of 1100 nm or less in double pass. Further, the side on which the recording material is not laminated may be surface-treated to prevent scratches.

Further, the transparent substrate may have a groove.

This groove is a guide groove necessary for tracking during optical recording and reproduction, and for example, in an optical disk, it is installed in a concentric circle or a spiral shape on the substrate surface. Of course, in the case of a rectangular recording material such as an optical card, parallel lines may be used.

The depth of the groove is λ/8n as in the case of phase difference photodetection.
(λ is the wavelength of the recording/reproduction light, n is the refractive index of the transparent substrate), or another depth may be used.

Silver or metal catalyst nuclei nobler than silver are formed on the transparent substrate or on the groove-forming surface of the transparent substrate having grooves by coating or adsorbing a composition containing them, or by using vacuum evaporation, sputtering, etc. . At this time, the amount of metal catalyst nuclei formed is determined by a change width of 1% in the reflectance of the transparent substrate.
A very small amount with no substantial change from the following is sufficient. If the range of change in reflectance is large, the metal silver particle dispersed layer will become non-uniform, which is not preferable. A particularly preferred formation method is a method of immersing the composition in a solution or dispersion of a composition containing metal catalyst nuclei, which allows uniform metal catalyst nuclei to be formed. For example, there are electroless plating catalyst nucleation methods in which metal catalyst nuclei of palladium are provided, such as a method of sequentially immersing in an aqueous solution of stannous chloride and an aqueous solution of palladium chloride, or a method of sequentially immersing in an aqueous organic palladium colloid solution and a reduced aqueous solution. These immersion liquids have a low concentration and viscosity, so when forming the metal catalyst nuclei on a transparent substrate having grooves with a fine groove structure, the metal catalyst nuclei can be formed without any unformed areas or unevenness in the grooves. A mask is formed.

The silver salt composition used in the present invention contains a vIA silver salt oxidizing agent, a reducing agent, and a hydrophobic binder as essential components,
Furthermore, various additives capable of enhancing material performance can be contained as optional components. For example, a compound that controls the size of silver particles in the metallic silver luster layer, such as a toning agent such as phthalazinone used in dry silver salt sensitive materials, can be added. Further, antifoggants, sensitizers, etc. can be added as necessary.

Organic silver salt oxidizing agents that can be used include silver salts of various carboxylic acids including long-chain fatty acids, silver salts of sancarinate, and silver salts of hensitriazole. Silver fluoroacetate and the like are particularly useful.

The hydrophobic organic polymer binder and U7 may be any organic polymer as long as it is hydrophobic; examples include polyvinyl butyral, polymethyl methacrylate,
These include polyvinyl formal, polycarbonate, cellulose acetate, cellulose butyrate, polystyrene, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, and the like. Two or more of these polymer binders can also be used in combination. The amount of these used is about 10:1 to about 1:1 by weight to the organic silver salt oxidizing agent.
0, preferably about 4:1 to 1:4.

Reducing agents include inhibiting phenols in which a sterically bulky group is bound to the carbon adjacent to the carbon to which the hydroxyl group is bound, sterically inhibiting the hydroxyl group, such as 2,6-di-t-butyl. -4-methylphenol, 2,2'-methylenebis-(4-methyl6-t-butylphenol),
2.2'-methylenebis-(4-ethyl-6-t,-butylphenol), 2.4.4-trimethylpentylbis-(2-hydroxy-3,5-dimethylphenyl)
Examples include methane, 2,5-di-t-butyl-4-methoxyphenol, and the like.

Also hydroquinone, 2,5-dimethylhydroquinone,
Reducing agents for silver salts such as chlorohydroquinone, p-aminophenol, methylhydronaphthalene, phenidone, methyl gallate, p-phenyldenol, bisphenol A
, 2,4-dihydroxybenzoic 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 about 10 mol, preferably about 0.1 mol, per 1 mol of organic silver salt oxidizing agent. It is about 3 moles.

The composition of these optical recording materials is prepared by dispersing or dissolving the above-mentioned essential components and optional components in an organic solvent, and coating the liquid on the metal catalyst nucleation surface of a transparent substrate and drying, preferably at an illuminance of 10 lux or less. Dry in a dark place. When the illuminance exceeds 10 lux, the organic silver salt oxidizing agent undergoes photodecomposition, reducing the recording sensitivity of the optical recording material. Furthermore, if the drying temperature is lower than 50°C, the solvent and trace water contained in the composition tend to remain, which is undesirable because defects such as bubbles and voids occur during the next heating. Further, when the temperature exceeds 80''C, the organic silver salt oxidizing agent decomposes, resulting in a decrease in recording sensitivity.

It is necessary to select an organic solvent to be used that does not swell or deteriorate the transparent substrate. 1 laminate thus prepared
Heat at a temperature of 00 to 200°C for a few seconds to about 10 minutes. At this time, it is important to consider the heat resistance of the transparent substrate and perform the heat treatment at a temperature below the heat distortion temperature. On the other hand, if it is less than 100'C, the formation rate of the metal silver particle dispersed layer is too slow to be practical. If the temperature exceeds 200°C, the metal silver particle layer 0 becomes non-uniform and cannot be used as an optical recording material.

Metallic silver particles are formed on the transparent substrate side of the silver salt composition by heating, and an optical recording material having a reflectance of 10 to 90% through the transparent substrate can be easily and quickly formed.

A protective layer may be provided to protect the recording layer of the optical recording material of the present invention, and in order to prevent warping, etc., two sheets of the recording material may be bonded together with the transparent substrate side outside, or a hollow type may be used. It can also have a sand inch structure.

The recording material of the present invention can be used as a so-called write-once recording material, and can be used for, for example, a write-once optical disc, a write-once compact disc, or an optical card. Of course, read-only ROM disks, compact disks,
It can also be used as a ROM card.

Examples are shown below, but the following examples are merely examples and do not limit the scope of the present invention in any way.

Example 1 Optical polycarbonate plate with a thickness of 0.4 mm (light transmittance 9
3%, birefringence double pass 40 nm) was covered with a protective film, and after being sequentially immersed in the following aqueous solutions for 10 seconds each, it was washed with water and air-dried.

(Aqueous solution 1) Stannous chloride 7g Distilled water 200ml concentrated hydrochloric acid 4ml (Aqueous solution 2) Palladium chloride 0.1g Distilled water 200ml concentrated hydrochloric acid
5 ml A suspension consisting of the following components was homogenized using a ball mill for about 13 hours, and then passed through a filter with an average pore size of 1.5 μm. This solution was uniformly applied onto the sample obtained above using a small applicator to a dry film thickness of 6 μm, and dried at 60° C. for 1 hour in a dark place with an illuminance of 5 lux.

Silver behenate 22g Polyvinyl butyral 18g Fucrazone 3g 2-t-butyl-6-(3-t-butyl-2-human-Uxy-5-methylbenzyl)4-methylphenylacrylate 8g Methyl ethyl ketone 170g Methanol 20g Toluene 55g Obtained When the resulting laminate was heated at 110° C. for 3 minutes, a sample was obtained in which the polycarbonate substrate side had a metallic luster with a reflectance of 40%.

It was confirmed that this sample could be recorded with a 10 mW 50 μs pulsed light from a semiconductor laser having an emission wavelength of 830 nm. Further, a good recording material was obtained, with no defects such as bubbles or short edges between the substrate and the metallic gloss layer.

Example 2 A glass substrate for a 5-inch optical disk with a thickness of 1.2 mm (
Metal development nuclei, that is, palladium nuclei, were formed on the surface using a catalyst nucleation method for electroless plating manufactured by Nippon Sailing Co., Ltd. . The method is shown below.

After being immersed in the following aqueous solutions for 20 seconds each, it was washed with water and air-dried.

(Aqueous solution 1) Activator Neo Gant 834 40 mfl (trade name of Nippon Sailing Co., Ltd.) Distilled water 956 ml Sodium hydroxide 3 g (Aqueous solution 2) Reducer Neo Gant WA 5 ml (trade name of Nippon Sailing Co., Ltd.) Boric acid 5 g Distilled water 950 m A solution consisting of the following components was stirred for about 1 hour to homogenize it, and then the solution was filtered through a filter with an average pore size of 1.5 μm, and then the solution was applied uniformly to a dry film thickness of 5 μm using a casting method, and the illumination intensity was 1. It was dried for 2 hours at a temperature of 60°C in a dark place below lux.

3 4 Silver trifluoroacetate 20g26-Gt
-Butyl-4 Methylphenol 9g2-Butanone
200g toluene
60 g polymethyl meccrylate 18 g The obtained laminate was heated at 150° C. for 5 minutes to obtain a sample having a metallic luster with a reflectance of 70% on the glass substrate side.

This sample was tested on an optical disc evaluation machine, and it was confirmed that the groove-based tracking servo worked, and it was also confirmed that recording and playback could be performed using a semiconductor laser. In addition, a good recording material without defects was obtained, with no bugs or air bubbles between the substrate and the metallic gloss layer.

(Effects of the Invention) According to the present invention, it is possible to provide a highly reliable optical recording material having no defects and comprising a reflective recording layer and a transparent substrate. Furthermore, it can be manufactured easily and inexpensively, and its effects are extremely large.

5

Claims (2)

[Claims] (1) A method for producing an optical recording material, in which a reflective recording layer in which metal silver particles are dispersed in a hydrophobic binder and a transparent substrate are laminated, and optical recording and reproduction are performed via the transparent substrate, Silver or a metal catalyst nucleus nobler than silver is formed on a transparent substrate having a transmittance of recording and reproducing light of 85% or more and a birefringence of 100 nm or less in a double pass without any substantial change in reflectance, and then organic silver hydrochloric acid A silver salt composition containing a reducing agent, a reducing agent, and a hydrophobic binder is formed, and then
An optical recording characterized in that a metal silver particle dispersed layer is formed densely on the substrate surface side of the silver salt composition by heating to 00°C, and the reflectance through the transparent substrate is 10 to 90%. Method of manufacturing the material. (2) In the method for producing an optical recording material according to claim (1), the transparent substrate has a groove formed in advance, and a reflective recording layer is laminated on the groove-forming surface of the substrate. A method for producing an optical recording material characterized by: