JPH0378699B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of the Invention] The present invention relates to an information recording medium having heat mode image recording characteristics. [Technical Background of the Invention] The present invention is an invention for improving an information recording medium having high sensitivity and heat mode image recording characteristics (for example, negative image recording characteristics), particularly in terms of image durability and reversibility of photographic characteristics. When the recording layer is an organic dye in an information recording medium that has conventional heat mode image recording characteristics, information is recorded by irradiating the recording layer with a high energy density beam (laser light) to melt or melt the organic dye in the irradiated area. This was done by forming depressions through evaporation. In an information recording medium having a recording layer made of such an organic dye, the organic dye layer is exposed on the surface, so when the recording medium is moved at high speed, it comes into contact with a roller, plate, etc. and the organic dye layer is exposed. There were cases where the product was damaged. When a protective layer is provided on the dye layer to protect such an organic dye layer, there are problems such as a decrease in recording sensitivity and image density. In other words, when a protective layer is formed on an organic dye layer by coating, the organic dye layer may be attacked by the coating solvent, or when a protective film is laminated, it may be attacked by the adhesive used or melted by heat. When deposited, there is a problem in that the organic dye layer may be deformed due to the heat, resulting in defects related to recording characteristics, etc., in the organic dye layer. In addition, an information recording medium having a sandwich structure in which at least one of two substrates has an organic dye layer and is bonded with the organic dye layer side facing inside, the organic dye layer is not exposed to the outside, so the above Although it has a function of preventing scratches and the like and has no adverse effect on recording characteristics, etc., it has the problem of complicating the manufacturing process and being disadvantageous in terms of manufacturing. Therefore, an information recording medium that has heat mode image recording characteristics, has excellent durability, and has photographic characteristics in which reversal does not easily occur has not been obtained. [Summary of the Invention] Various studies were conducted to improve the durability of the information recording medium, and it was found that by further providing a protective layer made of polymer latex on the organic dye layer, the recording material could come into contact with other materials, and In addition to eliminating scratches on the recording material due to friction, etc., the durability of images created by irradiating this information recording medium with a high energy density beam in the form of an image is significantly increased, and the amount of exposure can be increased. The present invention was achieved by discovering that the photographic characteristics are difficult to reverse even when the film is used. Therefore, it is an object of the present invention to provide durable recorded images in real time in heat mode image recording such as negative image recording, and to provide information whose photographic characteristics are difficult to reverse even when the exposure amount is increased. It provides a recording medium. The present invention resides in an information recording medium comprising a recording layer made of an organic dye on a support and a protective layer made of polymer latex provided thereon. Preferred embodiments of the present invention are as follows. (1) The polymer latex is polyvinyl acetate latex, ethylene-vinyl acetate copolymer latex, styrene-butadiene polymer latex, acrylonitrile-butadiene copolymer latex, methyl methacrylate-butadiene copolymer latex, Vinylidene chloride-acrylonitrile copolymer latex, vinylidene chloride-vinyl chloride copolymer latex, polychloroprene latex, polyvinylpyridine latex, polyisoprene latex, butyl rubber latex, polysulfide rubber latex, polyurethane latex, polybutene latex, Polyacrylate latex, polyethylene latex, methyl vinyl ether-maleic anhydride copolymer latex, polyvinyl bityral, polyvinylidene chloride-acrylonitrile copolymer, copolymer latex of alkali metal salt of ethylene and carboxylic acid ester, polyolefin latex The above-mentioned information recording medium is characterized in that it is at least one selected from the group consisting of latices, nitrocellulose, and acrylate and methacrylate latexes. (2) The above-mentioned information recording medium, wherein the thickness of the above-mentioned recording layer is in the range of about 10 nm to about 1 μm. (3) The surface of the support in contact with the recording layer of the support is made of polyethylene terephthalate, polymethyl methacrylate, polyolefin, epoxy resin, gelatin, methyl cellulose, polyethylene oxide, nitrocellulose, polyvinyl alcohol, cellulose diacetate, cellulose acid acetate, methyl vinyl ether. - The above information recording medium method, characterized in that it is a maleic anhydride copolymer, an ethylene-acrylic acid alkali metal salt copolymer, or a polycarbonate of bisphenol A. (4) The information recording medium described above, characterized in that a reflective layer is provided between the recording layer and the support. (5) The information recording medium described above, characterized in that a heat insulating layer is provided between the recording layer and the support. (6) The information recording medium described above, wherein the recording layer is made of an organic dye in which particles are dispersed. [Effects of the Invention] The information recording medium in which a recording layer made of an organic dye is provided on the support of the present invention and a protective layer made of polymer latex thereon can be used to record images in a heat mode such as negative image recording. Can provide durable recorded images in real time,
Furthermore, it has the characteristic that photographic characteristics are not easily reversed even if the exposure amount is increased. The inventors contact the organic dye layer with another one,
In order to improve durability by preventing scratches caused by friction, etc., we have repeatedly studied the material of the protective layer. It has also been found that when polymer latex is used as the material for the protective layer, the above characteristics are significantly improved in addition to improved durability. That is, the organic dye forming the recording layer of the present invention is
It is sensitive to external physical or chemical changes such as application of organic solvents or heat, and the formed recording layer is easily deformed. On the other hand, organic dyes are relatively stable in water, and it is possible to form a protective layer with a water-soluble resin. However, in the case of a protective layer made of water-soluble resin, the recording layer is not susceptible to deformation, but sufficient durability cannot be obtained with water-soluble resin. After repeated studies, the inventors found that by using the polymer latex described above, it is possible to provide durable recorded images in real time, and furthermore, the photographic properties do not easily reverse even if the exposure amount is increased. It has been found that it is possible to obtain an information recording medium having the following properties. That is, although polymer latex has the advantage of not attacking the dye layer like water-soluble resins, it also has better adhesion to dyes and supports than protective layers formed from water-soluble resins.
Furthermore, since it has excellent water resistance, it is possible to provide durable recorded images in real time. Furthermore, especially in the case of negative image recording, the polymer latex protective layer protects the dye with strong adhesion, inhibiting the decomposition of the dye, making it possible to obtain characteristics that make it difficult for the above photographic characteristics to reverse. it is conceivable that. [Detailed Description of the Invention] Next, the present invention will be described based on the drawings. FIG. 1 is a schematic cross-sectional view showing one configuration example of an information recording medium of the present invention. In FIG. 1, the supports are polyester (e.g., polyethylene terephthalate), polymethyl methacrylate, polyolefin, epoxy resin, cellulose acetate (e.g., cellulose diacetate, cellulose triacetate), polycarbonate (e.g., bisphenol A polyester). These include plastic films or plates made of carbonate), polyacrylates, polyamides (eg, nylon-6), paper, coated paper, glass, aluminum plates, or plastic films deposited with tin, aluminum, tellurium, isodium, etc. No. 3 is formed by densely packed fine particles (herein referred to as "particle dispersion").
The recording layer is mainly composed of an organic dye, which has a high light transmittance and whose melting point is generally 80° C. or higher, preferably 100° C. or higher.
4 is a protective layer. The information recording medium of the present invention is characterized in that, as described above, a recording layer made of an organic dye is provided on a support, and a protective layer made of polymer latex is provided thereon. The organic dye that can be used in the present invention is not particularly limited, and any organic dye that undergoes a physical or chemical change when irradiated with a high-energy-density beam and that causes a change in optical properties in the irradiated area. Anything is fine. For example, when recording information by forming a negative image, an organic dye is used that has a high light transmittance through the formed organic dye layer and has a property that the optical density increases when the organic dye layer is irradiated with a beam of high energy density. Bye. The organic dye layer may be a dye layer in which fine particles are densely packed (hereinafter referred to as a particle-dispersed organic dye layer) as described above. For example, the above particle-dispersed organic dye layer can be created by vacuum evaporating the organic dye onto a support, ion plating the organic dye onto the support, or dispersing the organic dye in a solvent in which the organic dye is not soluble. It can be made by coating it on a support with or without the addition of a binder. The thickness of the particle-dispersed organic dye layer ranges from about 10 nm to about 1 μm. Furthermore, a recording layer consisting of an organic dye that is not in a particle-dispersed state or has almost no particles can be obtained by dissolving the organic dye in an organic solvent that can dissolve the organic dye and coating this coating solution on a support. The absorption spectrum of an organic dye dispersed in particles is completely different from the absorption spectrum dissolved in a solvent.
Absorbance is low in the visible range. When an organic dye layer in which particles are dispersed is irradiated with a beam (for example, a laser beam) having a high energy density less than the amount of energy required to evaporate the organic dye in an imagewise manner, the absorbed light intensity increases and an image is formed. The energy required to increase the optical density of the particle-dispersed organic dye layer is less than the energy for sublimation or evaporation. The transmission optical density of the organic dye layer containing the dispersed particles in the visible light region is about 0.25 or less, preferably about 0.15 or less. After the particle-dispersed organic dye layer is irradiated with a high-density energy density beam, the increase in the transmission optical density of the organic dye layer (image area) in the visible light region is about 0.4 or more, preferably about 0.5 or more. In particular, the above-mentioned thickness of approximately
An organic dye layer in which particles in the range of 10 nm to about 1 μm are dispersed is preferred because it satisfies the aforementioned optical density. Furthermore, although the organic dye layer in which particles are dispersed hardly scatters visible light, the organic dye layer (image area) after being irradiated with a high-density energy density beam strongly scatters visible light. When an image created by the above method is enlarged with a microreader or the like and is read on a screen, the contrast between the image portion and the non-image portion is very large, making it easy to read the image or signal. On the other hand, when an organic dye layer is not in a particle-dispersed state or has very few particles, irradiation with a high-density energy density beam causes the irradiated area to melt, change the crystalline state, or form bits, and the optical properties of the irradiated area to change. Change. This allows recording and reading of images or signals. Examples of organic dyes used in the present invention include the following. First, there are organic dyes represented by the following chemical structural formula (). In the general formula (), Q represents an atomic group forming a 5- or 6-membered cyclic hydrocarbon. X is H, NO ₂ or OH, a substituent bonded to the 2nd or 4th position with respect to the carbon atom to which the azo group is bonded, Y is H, Cl, Br, CH ₃ or OCH ₃ represents. However, combinations in which both X and Y are H are excluded. W is H, Cl, Br, OH, _CH3 or _OCH3 , Z is H, OH,

[Formula] or -N=N-. However, combinations in which both W and Z are H are excluded. R ¹ and R ² represent a hydrogen atom, a methyl group, an ethyl group, a propyl group, a hydroxymethyl group, a 2-hydroxyethyl group, or a 3-hydroxypropyl group, and may be the same or different. Among the organic dyes represented by the above general formula (), preferred are organic dyes represented by the following general formula (). A is H or NO ₂ for the azo atomic group, 2
Represents a substituent bonded to the - or 4-position,
Y represents H or _CH3 . However, combinations in which both A and B are H are excluded. D represents H or OH; E represents H, OH or

[Formula] is represented, and R ³ and R ⁴ are both H, CH ₃ , CH ₂ , CH ₃ or
Represents CH ₂ CH ₂ OH, and R ³ and R ⁴ may be the same or different. However, combinations in which both D and E are H are excluded. When forming a negative image by carrying out the method of the present invention using a laser beam using the information recording medium of the present invention, organic dyes that are particularly preferred because of their high recording sensitivity are those in the general formula () where A is NO ₂ , B is H or CH ₃ , D is H or
OH, E is H, OH or

[Formula] (However, combinations in which both D and E are H are excluded.) R ³ and R ⁴ are both H, CH ₃ , CH ₂ CH ₃ or CH ₂ CH ₂ OH (R ³ and
R ⁴ may be the same or different. ) is an organic pigment represented by Specific examples of the organic dye represented by the above general formula are as follows. 2'-nitro-4-(dimethylamino)azobenzene 4'-nitro-4-(dimethylamino)azobenzene 4'-nitro-4-(N-methyl-N-2-hydroxyethylamino)azobenzene 4'-nitro- 4-(N-ethyl-N-2-hydroxyethylamino)azobenzene 2'-chloro-4'-nitro-4-(N-ethyl-
N-2-hydroxyethylamino)azobenzene 2-methyl-4'-nitro-4-(N-ethyl-
N-2-hydroxyethylamino)azobenzene 4'-nitro-4-aminoazobenzene 4'-nitro-4-[di(2-hydroxyethyl)
Amino]azobenzene 4'-methyl-4-[di(2-hydroxyethyl)
Amino]azobenzene 4'-nitro-2,4-dihydroxyazobenzene 4'-nitro-2-chloro-4-[di-(2-hydroxyethyl)amino]azobenzene Even if dyes other than the above are used, they can be added to the organic dye layer. An organic dye that has the property of increasing its optical density when irradiated with a beam of energy density, a change in the crystal state,
Alternatively, any organic dye that causes a change in the optical properties of the irradiated area by forming pits or the like can be used as the organic dye of the present invention. Such organic dyes are already known, and examples thereof include the following. For example, cyanine dyes, phthalocyanine dyes, pyrylium/thiopyrylium dyes, azulenium dyes, squalirium dyes, Ni,
Metal complex dyes such as Cr, naphthoquinone/anthraquinone dyes, indophenol dyes,
Indoaniline dyes, triphenylmethane dyes, triallylmethane dyes, aluminum-based dyes,
Mention may be made of diimmonium dyes and nitroso compounds. When an organic dye layer 3 in which particles are dispersed (Fig. 1) deposited on a support by a vacuum evaporation method is irradiated with a beam (for example, a laser beam) of high energy density in an amount less than the energy for evaporating the dye in an imagewise manner, , an image was created as the absorbance increased, but after 3 to 4 months of being left indoors, the absorbance decreased and the image began to disappear. However, completely unexpectedly, an organic dye layer 3 in which particles are dispersed is provided on a support 1 shown in FIG.
In the information recording medium coated with the material, the absorbance of the image created by irradiating the laser beam in the form of an image did not decrease after 3 to 4 months, and the absorbance remained almost the same after 10 months. That is, in the information recording medium of the present invention, the protective layer made of polymer latex has the effect of preventing the recording layer 3 from being damaged by external mechanical force or making the surface slippery, as well as the conventional effect of making the surface slippery. It also has the effect of significantly increasing the durability of recorded images. Furthermore, the protective layer made of polymer latex has the effect that a negative image can be obtained even if the exposure energy of the information recording medium is varied over a wide range, and that it will not be reversed even if high energy exposure is applied. The present invention requires the use of a polymer latex as described below as a protective layer. Thereby, it is possible to form a durable recorded image in real time by forming a negative image, and to obtain an image whose photographic characteristics are unlikely to be reversed even if the exposure amount is increased. Furthermore, even if images or signals are recorded not by negative image formation but by changes in optical properties, the protective layer of the polymer latex of the present invention provides durable recorded images or signals. I can do it. Furthermore, it is preferable to use a polymer latex for the protective layer in which the sum of the optical density (fog density, Dmin) of the particle-dispersed organic dye layer provided on the support and the optical density of the protective layer is 0.25 or less. Specific examples of polymer latex include polyvinyl acetate latex (e.g., ethylene-vinyl acetate copolymer latex, maleic acid-vinyl acetate copolymer latex), styrene-butadiene-based polymer latex (e.g., EBR latex, SBR
latex, SB latex, HS latex,
PS latex), acrylonitrile-butadiene copolymer latex, methyl methacrylate
Butadiene copolymer latex, polyvinylidene chloride copolymer latex, (e.g., vinylidene chloride-acrylonitrile copolymer latex, vinylidene chloride-vinyl chloride copolymer latex),
Polychloroprene latex, polyvinylpyridine latex, polyisoprene latex, butyl rubber latex, polysulfide rubber latex, polyurethane latex, polybutene latex, polyacrylate latex, polyethylene latex, natural rubber latex, methyl vinyl ether-maleic anhydride- Examples include copolymer latexes, copolymer latexes of ethylene and alkali metal salts of carboxylic acid esters, polyvinyl butyral, polyolefin latexes, and latexes of nitrocellulose and acrylates or methacrylates. As a method for providing a protective layer on an organic dye layer,
The above-mentioned latex is applied as it is, or with water added thereto, onto the organic dye layer in which particles are dispersed. The solvent may include a small amount of organic solvent in addition to water. The thickness of the protective layer is 0.4 μm or more and 10 μm or less, preferably 0.6 μm or more and 4 μm or less. If the protective layer is too thin, the durability of the image cannot be improved, and if it is too thick, the recording sensitivity will be reduced. Therefore, the range in which the durability of the image is enhanced and the recording sensitivity is not easily reduced is 0.6 μm or more and 4 μm or less. A resin layer made of an ultraviolet curable resin may be provided on the protective layer to further improve durability. FIG. 2 is a schematic cross-sectional view showing another example of the structure of the information recording medium of the present invention. 1 is a support, and 2 is an organic polymer layer different from the support, a porous heat insulating layer, or a reflective layer. 3 is an organic dye layer in which fine particles are densely dispersed. 4 is a protective layer, which is a feature of the present invention. The porous heat insulating layer may be made by any method, and examples of methods for forming the porous layer include the following. Using an organic polymer as a binder, fine particles that do not react with the binder (average particle diameter of approximately 0.2 μm to approximately 10 μm) are dispersed and coated on a support, and then only these fine particles are dissolved and removed to obtain a porous layer. be. Another method for forming a porous layer is a method for forming a membrane filter layer, which is described in US Pat. No. 3,129,159 and the like. The method of forming the membrane filter layer consists of a polymer being mixed with a liquid that is a good solvent for the polymer and another liquid that has a higher boiling point and is a non-solvent, or at least a poor solvent, for the polymer. The polymer solution is coated onto a support, and the coating is then dried. Because of their low boiling points, the good solvents mentioned above evaporate easily, and as this evaporation progresses, the poor solvent or non-solvent liquid becomes concentrated in the coating, which causes the polymer to become particulate. It begins to precipitate in the form of , and a close porous layer is formed on the support. A wide variety of polymers can be used to make membrane filter layers, typical examples being polycarbonates, polyamides, and cellulose esters. The organic layer may be formed by any method, for example, the following method. This is a method in which a solution of an organic substance in an organic solvent is applied to a support, or a layer of an organic substance is vacuum evaporated or ion plated. The thickness of the organic layer is from several tens of nm to 3 μm. For example, as the organic substance, the low melting point substance described in JP-A-54-66849 can be used. A transparent organic polymer layer is created by applying a solution of the polymer. Examples of organic polymers include polyvinyl butyral, polyvinyl formal, polymethyl methacrylate, polyvinyl alcohol, gelatin,
Ethylene-acrylic acid copolymer, ethylene-acrylic acid alkali metal salt copolymer, methyl vinyl ether-maleic anhydride copolymer, polyethylene oxide, methyl cellulose, cellulose triacetate, cellulose diacetate, ethyl cellulose, polyvinyl chloride, poly Examples include vinylidene chloride, acrylonitrile-vinylidene chloride copolymer, polybutadiene, polyvinyl acetate, polyvinylpyrrolidone, epoxy resin, and bisphenol A polycarbonate. When an organic dye layer is provided on an organic polymer coated on a support, the following organic polymers are preferable in terms of high recording sensitivity. Gelatin, acrylonitrile-vinylidene chloride copolymer, polyvinylpyrrolidone, polyvinyl alcohol, ethylene-acrylic acid ester alkali metal salt copolymer,
Methyl vinyl ether-maleic anhydride copolymer, polyethylene oxide, methyl cellulose,
It is a polycarbonate of cellulose triacetate and bisphenol A. The thickness of the organic polymer layer is approximately 0.5μ
m to approximately 5 μm. FIG. 3 is a schematic cross-sectional view when the information recording medium of the present invention (the one illustrated in FIG. 1) is irradiated with a beam of high energy density. In Figure 3,
1, 3, and 4 are the same as those shown in FIG. 5 is an image-like high energy density beam, 6
is a phase transition or melting of 3, and 6
The optical density of is higher than that of 3. The area irradiated with the high energy beam density generally becomes uneven. This unevenness also has the secondary effect of increasing the density of the image area and improving the contrast when projected onto the screen of a projection type reader (for example, a microfilm reader manufactured by Fuji Photo Film Co., Ltd.). In the information recording medium provided with the protective layer made of the polymer latex of the present invention, when irradiated with the image-like high energy density beam as described above, the recording layer undergoes a phase transition or melts, and the optical density of the irradiated area increases. Instead of recording an image by increasing the height of the recording layer, the recording layer may be removed by pits or the like. High energy density beams that can be used in the method of the present invention include laser light, light emitted from a Canon lamp, light emitted from a mercury lamp, and electron beams. In particular, laser light (e.g. He
-Cd laser, Kr laser, Ar laser, He-Ne laser, semiconductor laser), electron beams can be scanned and recorded on information recording media, so the energy beam can be modulated by electrical signals photoelectrically read from computer output or originals. It is useful because it can be done. The information recording medium of the present invention can be suitably used for various information recording media. For example, it is used for COM, ultra-micro imaging, micro-facsimile, video signal recording, etc. Furthermore, the information recording method by increasing optical density used in the present invention has the following characteristics: recording can be performed by irradiation with low energy, and photographic characteristics of negative image formation where the optical density is high in the area irradiated with a high energy density beam. to show that
DRAW (Direct
It has advantages such as read-after-write characteristics, the ability to handle it in a bright room, the durability of images, and the wide range of exposure energy at which negative images can be obtained. Next, examples of the present invention will be described. Examples 1 to 4 4′-nitro-4 on a 100 μm thick PET film
-(N-Ethyl-N-2-hydroxyethylamino)azobenzene was vacuum deposited to a thickness of 500 nm using a resistance heating method to prepare an organic dye layer in which particles were dispersed. On this dye layer, the latex shown in Table 3 is applied with a spinner with or without mixing with water.
It was applied at 2000 rpm for 20 seconds, and after drying, a protective layer was provided to prepare a recording medium. To this, argon laser light (wavelength 514.5 nm, beam diameter 10 μm) was applied with a scanning degree of 3.6
A negative image was obtained when irradiated at m/sec. These negative images did not turn brown after 10 months, and there was no reversal phenomenon in which the density of the negative images decreased even when the recording medium was exposed to light with an energy six times the recording value energy. The optical density (Dmax) of the irradiated area and the optical density (Dmin) of the unexposed area were measured using a microdensitometer.

[Table] The physical properties of the latex are shown below (1) Polyolefin latex Product name: Chemipearl S-100, manufactured by Mitsui Petrochemical Industries, Ltd., solid content 27%, viscosity 1000 cps, Vikatsu softening point 59°C (2 ) Nitrocellulose-acrylic polymer latex Product name: Cellnax-1000, Daicel Corporation
Manufactured, individual type concentration 45%, viscosity 50cps or less, PH6~
8. Anionic (3) Copolymer of styrene and butadiene Product name: Norcatex 2752, Sumitomo Naugatatsu Co., Ltd., solid content 48%, bound styrene content 49% (4) Ionomer (alkali of ethylene and carboxylic acid ester) Copolymer latex of metal salt) Product name: Corpolene Latex L-4000, manufactured by Asahi Dow Co., Ltd., solid content concentration approximately 40%, Vikatsu softening point
70°C, specific gravity 0.94 Reference Example 1 Instead of applying polyolefin latex as a protective layer in Example 1, an information recording medium without a protective layer was prepared and irradiated with Alcon laser light under the same conditions as Example 1. A negative image as shown in Table 2 was obtained, but it turned brown after 3 months, and only a faint residue remained after 5 months. It was found that the durability of the negative image of the information recording medium of Comparative Example 1 was inferior to that of Example 1, and that when exposed to laser light of 0.08 J/cm ² or more, the image was reversed and the image density became lower than Dmax. .

[Table] Example 5 The following known cyanine dyes 1 g was dissolved in isopropanol to prepare a coating solution for forming a dye layer (concentration: 1% by weight). Disc-shaped polycarbonate substrate (outer diameter: 130mm,
The coating solution was applied onto the surface (inner diameter: 15 mm, thickness: 1.2 mm) using a spin coating method at a rotation speed of 2000 rpm, and then dried at a temperature of 70°C for 10 minutes to a film thickness of 600 Å.
A recording layer was formed. Polymer latex coating liquid Styrene/butadiene latex (solid content:
10wt%, Nipol LX407C, manufactured by Zeon Corporation)
100 parts by weight The above-mentioned polymer latex coating solution was applied onto the obtained recording layer at a rotation speed of 700 rpm using a spin coating method, and then dried at a temperature of 120°C for 5 minutes to form a polymer latex with a film thickness of 20 μm. A protective layer was formed. UV curable resin coating liquid trimethylolpropane triacrylate
15 parts by weight dipentaerythritol hexaacrylate
15 parts by weight Tetrahydrofurfuryl alcohol 10 parts by weight Benzoin isopropyl ether 2 parts by weight Furthermore, the above-mentioned ultraviolet curable resin coating liquid is applied onto the above-mentioned protective layer, and the coating layer is cured by irradiating with a 2Kw ultraviolet lamp for 10 seconds, An ultraviolet curable resin protective layer was provided as a functional layer with a layer thickness of 5 μm. In this way, an information recording medium consisting of a substrate, a recording layer, a latex protective layer and an ultraviolet curable resin protective layer was manufactured. Comparative Example 1 Water-soluble resin coating liquid Polyvinyl alcohol 10 parts by weight Water 100 parts by weight Example 5 except that the above-mentioned water-soluble resin coating liquid was applied instead of the polymer latex protective layer to provide a protective layer. An information recording medium was manufactured in the same manner. Evaluation tests were conducted on the information recording media obtained in Example 5 and Comparative Example 1 as follows. (1) Recording of information When the obtained information recording medium was rotated and irradiated with a laser beam with a wavelength of 830 nm from the substrate side, pits were formed on both media, confirming that information could be recorded. (2) Adhesiveness When the adhesiveness between each layer of each of the obtained information recording media was evaluated by cellophane tape peeling test, no peeling occurred between any layers in Example 5, but partial peeling occurred in Comparative Example 1. It occurred in (3) Condition of dye recording layer When observing what kind of changes occurred in the dye recording layer when a protective layer etc. was applied thereon, it was found that Example 5 was not affected by the overcoat. Although there was no change, surface condition deterioration occurred in Comparative Example 1.

[Brief explanation of drawings]

1 and 2 are schematic cross-sectional views showing the structure of the information recording medium of the present invention, and FIG. 3 is an explanatory view showing a method of recording on the information recording medium of the present invention. 1: Support, 2: Organic polymer layer, organic substance layer or heat insulating layer, 3: Recording layer consisting of organic dye in which particles are dispersed, 4: Protective layer, 5: High energy density beam, 6: Image area.

Claims (1)

[Claims] 1. An information recording medium comprising a support, a recording layer made of an organic dye, and a protective layer made of polymer latex provided thereon.