JPH031733B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an optical information recording medium, and more specifically, the present invention relates to an optical information recording medium containing one or more compounds selected from the group consisting of silicic acid, polyorganosiloxane, and silyl ether between a substrate and an information recording layer. The present invention relates to an optical information recording medium provided with layers. "DRAW" (Direct Read
2. Description of the Related Art Recently, the use of a recording medium having an after-write characteristic or an erasable recording medium as a memory medium for video information such as document files and image files has been attracting attention. Conventionally, glass substrates with excellent smoothness have been used as substrates for such recording media, but these have had problems such as being heavy and easily damaged and dangerous when handled. For the above reasons, synthetic resins have also been used as substrates. However, during the manufacturing process of sheet or film-like substrates made of synthetic resin, dust, foreign matter, scratches, unevenness, etc. of several micrometers may be present on the substrate due to frictional electrification or contamination of foreign matter due to process operations. is unavoidable. Since the surface of synthetic resin cannot be polished to a mirror finish to remove these particles, surface defects such as the above foreign particles cause noise and dropouts during optical recording and reproduction of information, which poses a practical problem. . Furthermore, the surface of the synthetic resin is often hydrophobic and has poor adhesion to the recording layer. In particular, when applying an aqueous solution containing metal fine particles dispersion containing a hydrophilic substance to an information recording layer, etc., pinholes, uneven coating, repelling, etc. occur, which has become a very serious problem. In order to solve this drawback, it is known that a layer for recording information is provided by vapor deposition after forming a vapor-deposited film of silicon dioxide on the substrate (for example, tellurium). Also, the adhesive strength between silicon dioxide and the information recording layer was not sufficient. As another method for solving this drawback, the present applicant has proposed in Japanese Patent Application No. 1983-1982 that this problem can be solved by subjecting the surface of the synthetic resin substrate to gas discharge treatment such as plasma discharge and chemical treatment such as alkali immersion treatment.
This method was proposed as No. 13350, and although a certain degree of adhesion can be obtained by this surface treatment, this method requires many processing steps, and the equipment used in the gas discharge treatment becomes larger due to the use of high voltage and high frequency. The disadvantage was that the risk could not be completely eliminated. The object of the present invention is to eliminate the above-mentioned disadvantages and to:
An object of the present invention is to provide an optical information recording medium which is formed by simply applying an information recording layer that has good adhesiveness to a substrate and has a stable adhesiveness that does not deteriorate over time, and also provides an optical information storage It is an object of the present invention to provide an optical information recording medium having a good S/N ratio by removing surface defects of the substrate or information recording layer that cause noise and dropouts during recording and reproduction. It is an object of the present invention to provide an optical information recording medium that records and reproduces information using a high-density energy beam, in which an information recording layer is formed between a substrate and an organic material layer in which fine metal particles are dispersed. A layer containing one or more compounds selected from the group consisting of silicates, polyorganosiloxanes, and silyl ethers (hereinafter referred to as undercoat layer)
This can be achieved by an optical information recording medium characterized by being provided with. The present invention will be explained in more detail. The present invention relates to an optical information recording medium that records and reproduces information using a high-density energy beam. irradiating the recording medium with a high-density energy beam from the substrate side or the opposite side of the substrate to blow off the information recording layer and eliminate the reflectivity of the information recording layer in the recording portion. It is done by twisting. The part of the record that is blown away is called a pit. On the other hand, in order to reproduce information, a high-density energy beam is irradiated onto the recorded recording medium from the substrate side or the opposite side of the substrate, and the information is read and reproduced using the reflectivity of the information recording layer. That is, since the pit portion has no reflective property, the high-density energy beam is hardly reflected, and the beam is well reflected in the unrecorded portion. Next, the present invention will be explained in detail with reference to the drawings. 1, 2, and 3 are cross-sectional views of exemplary embodiments of the present invention. In FIG. 1, 1 is a substrate (preferably made of synthetic resin), 3 is an information recording layer containing dispersed metal fine particles, and is coated with a dispersion liquid made of an organic material in which the metal fine particles are dispersed and suspended. It is formed by 2 is an undercoat layer provided between the substrate 1 and the information recording layer 3. The layer structure shown in FIG. 1 is the basic structural unit of the present invention. In FIG. 2, 4 is a layer in which a reducible metal salt is dispersed in a dispersion medium consisting of an organic layer, for example, a silver halide emulsion layer used in a photographic light-sensitive material;
Fogging nuclei that become the precipitation nuclei of metallic silver are generated by exposure or fogging agent, and then physical development (generally reduction) is performed.
This is to generate silver (generally metal) fine particles to form the information recording layer 3. In addition, FIG. 3 shows the information recording layer 3 of the basic structural unit.
For example, the above-mentioned silver halide emulsion layer 4 was further coated thereon, and the metal fine particles dispersed in the information recording layer 3 were physically developed as precipitation nuclei of metallic silver from the layer 4 to reinforce the metal fine particles. Thereafter, the silver halide emulsion layer 4 is peeled off to obtain the basic structural unit. Further, as shown in FIG. 4, a physical development nucleus layer 5 containing physical development nuclei particularly suitable for physical development is added to the emulsion layer 4.
It is also possible to provide a structure between the information recording layer 3 and the information recording layer 3. It should be noted that the developer used in the above-mentioned physical development may have the following composition, for example. It is preferable to wash with water after development. Example of physical developer Development conditions: 30°C, 60 seconds Phenidone 1.0g Anhydrous sodium sulfite 65.0g Hydroquinone 12.0g Potassium hydroxide 15.0g Potassium bromide 0.5g Sodium thiosulfate 5.0g Add water 1 Also, embodiments of the present invention In this case, a polymeric protective film can be provided directly on the information recording layer 3, which is the basic structural unit, or by providing an adhesive layer and using means such as lamination or coating. Furthermore, an optical information recording medium having a double structure may be obtained in which the information recording layers of the basic structural unit having information recording layers of the same type or different types are faced to each other, and a spacer is provided between them and fixed by adhesive. It is preferable that the above-mentioned protective film and spacer be substantially transparent to the high-density energy beam when information is recorded or reproduced from the substrate side using the high-density energy beam; The membrane and the spacer need not be substantially transparent to the high density energy beam. Further, the thickness of the substrate 1 used in the present invention is not limited at all, and in practice, it can be used from 7 μm to 30 mm without any problem, and a tracking guide groove may be provided as necessary. The undercoat layer according to the present invention is preferably a layer that has an affinity for the substrate (preferably made of a synthetic resin with relatively low surface hardness) and the organic layer constituting the information recording layer. This layer contains one or more compounds selected from the group consisting of acid salts, polyorganosiloxanes, and silyl ethers. The silicates are salts consisting of silicon dioxide and metal oxides, and include hydrated salts, double salts, and other forms containing negative atomic groups such as other acid groups (e.g.
(aluminosilicate containing Al ₂ O ₃ , borosilicate containing B ₂ O ₃ , etc.). In addition, the metal atoms contained in the silicate include Al, Fe(),
There are Ca, Mg, Na, K, etc., and it is desirable that the silicic acid used in the present invention is water-soluble.If it is water-insoluble, it can be treated with alkali hydroxide or alkali carbonate to make it water-soluble. can.
In addition, from the viewpoint of ease of application and ease of handling, potassium silicate, which is a compound with a composition of potassium oxide and silicon dioxide combined, or sodium silicate, which is a sodium salt of silicic acid, is particularly preferred as the silicate. . Examples of the potassium silicate include potassium metasilicate (K ₂ SiO ₃ ) and potassium hydrogen disilicate (KHSiO ₅ or K ₂ Si ₄ O ₉ ·H ₂ O).
Examples of the sodium silicate include sodium metasilicate (NaSiO ₃ ) and its various hydrated salts, sodium orthosilicate (Na ₄ SiO ₄ ), sodium disilicate (Na ₂ SiO ₅ ), and sodium tetrasilicate (Na ₂ Si ₄ O ₉ ), etc. The silicate-containing undercoat layer according to the present invention also has the advantage of increasing the hardness of the substrate and preventing the occurrence of scratches and the like during the production of the information recording medium. The undercoat layer using silicate according to the present invention is
The film was superior in film strength and adhesion to the substrate and information recording layer than the conventional undercoat layer made of a vapor-deposited film of silicon dioxide, but this is because the layer using the silicic acid is applied by coating, so the layer is ionic. Because it is formed by strong bonds, it is considered to be superior to an undercoat layer made of a vapor-deposited film of silicon dioxide, which is formed by intermolecular forces. What is the polyorganosiloxane?

Among polymer compounds composed of the basic unit of [formula]

[Formula] indicates a polymer compound composed of a basic unit in which an organic group R is bonded to a silicon atom, such as a chain polyorganosiloxane such as R-(R ₂ SiO(-nSiR ₃₎ . , ( _R2SiO )
There are cyclic polyorganosiloxanes such as n, and ladder-like, cage-like, and three-dimensional network-like polyorganosiloxanes, and any of these can be used in the present invention (n represents a positive number). It also contains an organic group (Rc) in the main chain of the polymer.

[expression] or

Polyorganosiloxanes having the formula [formula] as a basic unit can also be used in the present invention. The polyorganosiloxane will be explained in more detail by way of example. Examples of the chain polyorganosiloxane include those shown in Table (a) below.

[Table] In Table (a), methyl group, phenyl group, hydrogen atom, chlorine atom, bromine atom, hydroxyl group, methoxy group, vinyl group, ClCH ₂ −, HOCH ₂ −,
NCCH ₂ CH ₂ −, CF ₃ CH ₂ CH ₂ CH ₂ −, HOOC
Represents either (CH ₂ ) ₃ − or an acetoxy group. In each of formulas 1 to 6, R may be the same or different. n and m represent positive numbers. Examples of the basic skeletons of the above-mentioned cyclic polyorganosiloxanes and ladder-shaped, cage-shaped, and three-dimensional network-shaped polyorganosiloxanes are those shown in Table (b).

【table】

【table】

[Table] In Table 10 to 16 of (B), R is a methyl group, phenyl group, hydrogen atom, chlorine atom, bromine atom, hydroxyl group,
Methoxy group, vinyl group, HOOC(CH ₂ ) ₃ −,
ClCH ₂ −, HOCH ₂ −, NCCH ₂ CH ₂ −,
CF ₃ CH ₂ CH ₂ CH ₂ −, or an acetoxy group, and in each formula of 10 to 16, R
may be the same or different. Polyorganosiloxanes according to the present invention also include polyorganosiloxanes obtained by polymerizing the compounds represented by the formulas in Table 2 (b) with open rings. In addition, polyorganosiloxanes include Al, Ti, B, Ge,
Polyorganosiloxanes according to the present invention also include those containing elements such as Sn, P, As, Mg, Pb, Zr, Sb, Cr, Fe, and Ni in the form of covalent bonds. The silyl ether is at least one

[Formula] (x represents an element other than a silicon atom) indicates a low molecular weight organic compound having a bond,
For example, commercially available silane coupling agents and the like are included. For example, there are compounds shown in Table 1 below. Among the group consisting of silicates, polyorganosiloxanes, and silyl ethers, a case containing at least a silicate is particularly preferred since it provides a wide range of substrate selection. The undercoat layer according to the present invention can also be formed by coating. Any solvent can be used for the coating solution as long as it dissolves the silicate, organopolysiloxane, silyl ether, etc. and the organic polymer compound as a binder added as necessary. Preferably it is a solvent. That is, it is preferable to use water, alcohols such as methanol and ethanol, ketones such as acetone methyl ethyl ketone, and ethers such as methyl cellosolve and tetrahydrofuran. In addition, one selected from the group consisting of the above-mentioned silicates, polyorganosiloxanes and silyl ethers.
30 parts by weight of a hydrophilic organic polymer compound as the binder along with 100 parts by weight of a species or two or more compounds.
By using less than one part by weight, it is possible to improve the coating properties and the dry strength of the coating film. Examples of hydrophilic organic polymers include natural polymers such as gelatin, gelatin derivatives, gum arabic, albumin, and agar, and hydrophilic polymers such as polyvinyl alcohol, polyvinylpyrrolidone, cellulose ether, cellulose acetate, polyacrylic acid, and polyacrylamide. Synthetic polymers can be used. Furthermore, the coating of the undercoat layer 2 is carried out in a room with clean air to prevent dust, foreign matter, etc. from entering the polymer layer. When the substrate is a flat plate, the coating method is suitable, such as the dipping method or bar coating method.If the substrate is a disk, the spin coating method is suitable.For film-shaped substrates, the dipping method or bar coating method is suitable. , roll coating method, etc. can also be applied. The same applies to the coating of the information recording layer 3, emulsion layer 4, etc. The film thickness of the undercoat layer can be substantially coated.
0.01 μm to 1 μm is practically preferable.
If it is less than 0.01 μm, it is difficult to coat, and it is inconvenient to fill in the irregularities (0.1 μm before and after) of the substrate 1 and provide a smooth surface base for the information recording layer 3, etc., which is laminated. Optical troubles due to density are likely to occur. The undercoat layer according to the present invention provided extremely good adhesion between the substrate and the information recording layer. Further, the undercoat layer according to the present invention makes it possible to remove dust, foreign matter, scratches, irregularities, etc. on the substrate, and eliminates noise and dropouts caused by these. In addition, the undercoat layer according to the present invention can prevent the information recording layer from being damaged due to poor adhesion between the undercoat layer and the information recording layer when the information recording layer, etc. is coated on the undercoat layer. Pinholes, uneven application, repellency, etc. are gone. Further, since the undercoat layer according to the present invention can be formed by coating, the equipment can be simplified and the danger is reduced compared to gas discharge treatment or the like. Examples of high-density energy beams that can be used in the present invention include mercury arc lamps, xenon flash lamps, and laser beams. Laser light is preferred as the energy beam, and both continuous wave oscillation and pulse oscillation laser light can be used.Specifically, ruby laser, argon ion laser, glass laser,
He−Ne laser, Kr ion laser, He−Cd ⁺
Examples include lasers, dye lasers, semiconductor lasers, and the like. Furthermore, in the optical information recording medium of the present invention, a layer structure is provided that allows laser light for recording and reproduction to be irradiated onto the information recording layer 3 from the substrate 1 side or from the opposite side. Can be done. In the present invention, the substrate 1 has a protective function for the information recording layer 3, and may be transparent or opaque to recording and reproduction laser beams, but is preferably substantially transparent. Something is chosen.
For example, polymethyl methacrylate, a copolymer mainly composed of methyl methacrylate, a sheet or film mainly composed of polyvinyl chloride, polystyrene, polyester, or polycarbonate can be used. In particular, polymethyl methacrylate is particularly suitable for the present invention because it has excellent surface smoothness and optical properties. The information recording layer 3 used in the present invention preferably consists of an organic layer in which fine metal particles are dispersed, and the average particle size of the fine metal particles is 100 to 300 Å.
Metals include Cu, Ag, Au, Ni, Pd, Pt, Fe,
Although Co, In, and Tl can be used as dispersion media, various synthetic polymer compounds can be used, including gelatin, gelatin derivatives, gum arabic, albumin, agar, natural polymer compounds such as cellulose, polyvinyl alcohol, polyvinylpyrrolidone, cellulose ether, and polyamide. It is preferable to use a hydrophilic synthetic polymer compound such as cellulose acetate. When the information recording layer 3 is obtained by coating the hydrophilic aqueous solution in which fine metal particles are dispersed, the adhesiveness with the undercoat layer 2 according to the present invention described above is extremely good. The dispersion solution of metal fine particles can be easily produced by a solution reduction method using a suitable reducing agent for the metal salt used, such as a nitrate, sulfate, halide, or peroxide. The content of colloidal metal fine particles in the dispersion solution is usually 1 to 20
Weight%. The thickness of the information recording layer is arbitrary, but if the thickness is 0.01 μm or less, it is difficult to coat and it is difficult to ensure flatness, and if it is 1 μm or more, it is not practical due to flatness. Although it may not be preferable, it is preferably 0.01 μm to 1 μm. Further, in the case where a photosensitive silver halide emulsion layer 4 is provided as the information recording layer matrix shown in FIG. 3, and in the case where the physical development nucleus layer 5 and the silver halide emulsion layer 4 shown in FIG. Similarly, favorable adhesion properties were obtained for both cases. The adhesion between the information recording layer 3 and the undercoat layer 2 can be further enhanced by adding a suitable silane coupling agent to the hydrophilic aqueous solution in which fine metal particles are dispersed or to the silver halide emulsion. For example, SH-6020, SH-6026, SH manufactured by Toray Silicone Co., Ltd.
−6032, SH-6050, SH-6075, SH-6040, etc.
or KBM-403, KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.
KBM-602 etc. are used, but when a polymethyl methacrylate substrate is used, especially the above-mentioned SH
-6020 had extremely good adhesion to the information recording layer. Similar to the silane coupling agent described above, a titanium coupling agent can also be used. Examples of titanium-based coupling agents include Kenrich in the United States.
Preact TTS manufactured by Petrochemicals,
38S, 46B, 55, 138S, 134S, etc. can be used, but when used in a dilute solution, 46B provided particularly excellent adhesion to polymethyl methacrylate substrates. The silane coupling agent and the titanium coupling agent are as shown in Tables 1 and 2.

【table】

【table】

[Table] The optical information recording medium according to the present invention, which can be produced, for example, as described above, has an information recording layer that has good adhesion to a substrate and has a stable adhesion that does not deteriorate over time. It was an optical information recording medium coated with Furthermore, the optical information recording medium had a good S/N ratio and was free of surface defects in the substrate or information recording layer that would cause noise and dropouts during optical recording and reproduction of information. EXAMPLES The present invention will be specifically described below with reference to Examples, but the embodiments of the present invention are not limited thereby. Example 1 Clean 8-inch square, 1 mm thick polymethyl methacrylate substrate (Acrylite manufactured by Mitsubishi Rayon Co., Ltd.)
5% of sodium metasilicate (manufactured by Wako Pure Chemical Industries) on top
Dry film thickness is increased by dipping using an aqueous solution.
A layer of the sodium silicate was provided to a thickness of 800 Å. After drying, an aqueous gelatin dispersion solution of colloidal silver containing 0.5% by weight of a silane coupling agent (SH-6020 manufactured by Toray Silicone Co., Ltd.) was applied using a wire bar to a dry film thickness of 0.3 μm. A recording layer was provided. The gelatin-dispersed aqueous solution of colloidal silver particles was obtained by reducing silver nitrate with dextrin, the weight ratio of silver to gelatin was 32%, and the particle size of the colloidal particles was about 300 Å. The adhesion of this sample when dry was examined by a peel test using a self-adhesive tape, and it was found to be good with no peeled portions observed. By coating a silver halide emulsion on the sample and subjecting it to physical development, the surface of the colloidal silver layer on the substrate side of the information recording layer is exposed to the following recording laser beam at 42°C.
The information recording layer was reinforced with a reflective surface having a reflectance of 50%. The obtained optical information recording medium sample of the present invention was scanned with 8 mW He-Ne laser light (6328 Å) at a scanning speed of 5.2 m/sec on the recording surface with a beam diameter of 1.4 μm. Then, writing and recording was performed by applying a pulse signal of 500 nsec using an acousto-optic device to form pits. After that, reproduction was performed using continuous 0.5 mW He-Ne laser light, and an S/N ratio of 47 dB was obtained. When the reflected light intensity was observed on an oscilloscope, almost no noise was observed in the unrecorded areas. Example 2 The same procedure as in Example 1 was carried out except that potassium metasilicate was used instead of sodium metasilicate, and the same good results were obtained in terms of adhesiveness and recording/reproducing S/N ratio. Example 3 Example 1 was carried out in the same manner as in Example 1 except that sodium aluminosilicate was used instead of sodium metasilicate, and the same good results were obtained in terms of adhesion and recording/reproduction S/N ratio. Example 4 When the same procedure as in Example 2 was carried out except that 3% by weight of polyacrylic acid was added to a 5% aqueous solution of potassium metasilicate, the same good recording/reproduction S/N ratio was maintained. Adhesion was also good. Example 5 In Example 1, 5% by weight of silane coupling agent SH-6040 manufactured by Toray Silicone Co., Ltd. was added to sodium metasilicate as a methanol solution, and an optical information recording medium was obtained in the same manner. .
The recording medium provided good adhesion. Further, when recording was performed using a He--Ne laser beam in the same manner as in Example-1, a good reproduced signal S/N ratio of 42 dB was obtained. Example 6 An optical information recording medium was obtained in the same manner as in Example 2 except that 1% by weight of silicone oil was added to potassium metasilicate as a tetrahydrofuran solution. The recording medium provided good adhesion. In addition, a good reproduced signal S/N ratio of 40 dB was obtained using the same recording method as in Example-1. Comparative Example-1 When a melamine resin paint was used instead of the sodium metasilicate aqueous solution in Example 1,
The colloidal silver coating solution caused some repellency and the recording layer became non-uniform, making it undesirable as an optical information recording medium. Comparative Example-2 The same procedure as in Example 1 was carried out except that a vapor-deposited film of silicon dioxide was provided instead of the sodium metasilicate aqueous solution, and the dry adhesion of the thus prepared sample was determined to be self-adhesive. When a peel test using a tape was conducted in the same manner as in Example-1, there were many peeled parts and the sample was inferior to the sample in Example-1. Comparative Example 3 When the undercoat layer in Examples 1 to 4 was not used, that is, when the hydrophilic colloidal silver dispersion was applied directly onto the polymethyl methacrylate substrate, repelling occurred and the application could not be completed. The hydrophilic colloidal silver dispersion is obtained by reducing silver nitrate with dextrin using an aqueous gelatin solution as a dispersion medium, the weight ratio of silver to gelatin is 32%, and the particle size of the colloidal particles is about 300 Å. It was hot. From the above, it has been found that the undercoat layer according to the present invention has a great effect on the adhesiveness between the information recording layer and the like and the substrate, especially the synthetic resin substrate.

[Brief explanation of the drawing]

1 to 4 are partial cross-sectional views of the optical information recording medium of the present invention. In the figure, 1 is a synthetic resin substrate, 2 is an undercoat layer according to the present invention, 3 is a metal fine particle dispersion layer, 4 is a layer in which a reducible metal salt is dispersed in a dispersion medium consisting of an organic layer, and 5 is a physical layer. This is a physical development nucleus layer containing development nuclei.

Claims (1)

[Claims] 1. In an optical information recording medium that records and reproduces information using a high-density energy beam, a silicate material is provided between a substrate and an information recording layer consisting of an organic layer in which fine metal particles are dispersed. 1. An optical information recording medium comprising a layer containing one or more compounds selected from the group consisting of polyorganosiloxane and silyl ether. 2 The thickness of the layer containing one or more compounds selected from the group consisting of silicates, polyorganosiloxanes, and silyl ethers is 0.01
2. The optical information recording medium according to claim 1, wherein the optical information recording medium has a thickness of 1.0 μm to 1.0 μm. 3. The optical information recording medium according to claim 1 or 2, wherein the substrate is a polymethyl methacrylate plate. 4. The optical information recording medium according to claim 2 or 3, wherein the organic substance of the organic substance layer is gelatin.