JP2003276337A - Information recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information recording medium which can form an image using a water-base ink and can form and erase an image by utilizing heat generated upon laser beam irradiation. <P>SOLUTION: This information recording medium is characterized by comprising: a reversible thermal recording layer containing a usually colorless or light- colored leuco dye, a photothermal conversion dye, and a reversible thermal developer which can cause color development of the leuco dye upon heating and can erase the color upon reheating; and at least one ink-receptive layer. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reversible information recording medium whose color tone changes reversibly by controlling heat energy.

[0002]

2. Description of the Related Art In recent years, there is an increasing demand for recording information by combining a plurality of recording methods. In particular, in a magnetic recording medium or an optical recording medium, there is an increasing demand for recording and organizing images and characters representing the recorded contents of the medium on the surface opposite to the surface for writing / reading.

As such an optical recording medium on which an image can be recorded, an optical recording medium which is provided with an ink receiving layer on the surface opposite to the surface on which optical writing / reading is performed and which can be printed by an ink jet system is becoming common. is there.

However, in such a conventional information recording medium, once an image is formed, it is impossible to erase the portion and return to the state before the image is formed again. There was no choice but to add to the part where the image was not formed. Therefore, when the area of the heat-sensitive recording portion is limited, there is a problem that the recordable information is limited and it is impossible to record all the necessary information.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an information recording medium capable of forming an image using an aqueous ink and forming / erasing an image by heat generated by irradiating a laser beam. .

[0006]

As a result of studies to solve these problems, the present inventors have found that the above invention can solve the above problems.

At least one reversible thermosensitive recording layer containing a colorless or light-colored leuco dye, a photothermal conversion dye, and a reversible developer that develops the color of the leuco dye by heating and reheats it to decolorize it. An information recording medium provided with the ink receiving layer of.

The above information recording medium is characterized in that at least one heat insulating layer is provided between the ink receiving layer and the layer containing a photothermal conversion dye.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention provides an information recording medium capable of forming an image using an aqueous ink and forming / erasing an image by heat generated by irradiating a laser beam. The components of the present invention, the recording method and the manufacturing method will be described below.

The information recording medium according to the first invention comprises an ink receiving layer, a reversible thermosensitive recording layer and a support.

When the ink-receiving layer according to the present invention is provided on the reversible thermosensitive recording layer, a highly transparent ink-receiving layer is preferable in terms of improving the visibility of the reversible thermosensitive recording layer.
When such an ink-receiving layer contains a hydrophilic polymer, preferably a surfactant having an HLB value of 3 to 8, and an inorganic pigment, a cationic polymer, a hardener, etc. at appropriate times (hereinafter referred to as “swelling property”). "Ink receiving layer"), hydrophilic polymer, inorganic fine particles, preferably primary particles having an average particle diameter of 5 to 5
In some cases, the inorganic fine particles of 50 nm and a surfactant having an HLB value of 3 to 8 are contained, and an inorganic pigment, a cross-linking agent, a cationic polymer and the like are contained at appropriate times (hereinafter referred to as “void ink receiving layer”). The coating liquid for the ink receiving layer is applied so that a coating layer having a thickness of several tens to several hundreds μm is formed on the support, and then dried. A preferred example of the manufacturing method is
The ink receiving layer applied to the information recording medium is once cooled in an atmosphere of 20 ° C. or lower, and then dried in a drying step.

In the present invention, the hydrophilic polymer used in the case of the swellable ink receiving layer is gelatin, polyvinyl alcohol, polyvinylpyrrolidone, polyvinylpyridinium halide, polyacrylamide, sodium polyacrylate, starch, carboxy starch, cationic starch, Examples thereof include dialdehyde starch, casein, ethyl cellulose, carboxymethyl cellulose, polyethylene glycol, polypropylene glycol, styrene-maleic anhydride copolymer and modified products thereof.

In the present invention, the inorganic fine particles used in the porous ink receiving layer include light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, titanium dioxide, zinc oxide, zinc hydroxide, calcium silicate and silicic acid. Examples thereof include magnesium, synthetic silica, alumina, hydrated alumina, aluminum oxide, magnesium hydroxide and the like. Preferably, the average particle size of the primary particles is 5 to 5
Inorganic fine particles of 0 nm are used, and synthetic silica, alumina,
Alumina hydrate is selected.

The synthetic silica is classified into a wet method and a vapor phase method. Usually, silica fine particles often refer to wet-process silica. As the wet process silica, silica sol obtained through metathesis of sodium silicate with an acid or the like or an ion exchange resin layer, or colloidal silica obtained by heating and aging this silica sol, and gelation of the silica sol, and by changing the formation conditions thereof Silica gel in which primary particles of several μm to 10 μm are siloxane-bonded to form three-dimensional secondary particles, and further silica sol, sodium silicate, sodium aluminate, etc. There are synthetic silicic acid compounds and the like.

Vapor phase silica is also called a dry method as opposed to a wet method, and is generally produced by a flame hydrolysis method. Specifically, a method of burning silicon tetrachloride with hydrogen and oxygen is generally known, but instead of silicon tetrachloride, silanes such as methyltrichlorosilane and trichlorosilane may be used alone or in the form of silicon tetrachloride. It can be used as a mixture with. The vapor phase silica is available from Aerosil Japan and QS from Tokuyama Corporation.
It is commercially available as a type and can be obtained.

In the present invention, the solid content per unit area of the ink receiving layer is generally 10 g / m ² or more, and 1
The range of 3 to 35 g / m ² is preferable.

The porous ink receiving layer used in the present invention has a binder for maintaining the characteristics as a film. As the binder, a hydrophilic polymer having high transparency and high penetrability of ink is preferably used. In using the hydrophilic polymer, it is important that the hydrophilic polymer does not swell and block the voids during the initial permeation of the ink, and from this viewpoint, it is exemplified as the hydrophilic polymer used in the swellable ink receiving layer. Among the types, hydrophilic polymers having a low swelling property at around room temperature are preferably used. Particularly preferred hydrophilic polymers are fully or partially saponified polyvinyl alcohol or cation-modified polyvinyl alcohol.

Among the polyvinyl alcohols, those partially or completely saponified with a saponification degree of 80% or more are particularly preferable. Polyvinyl alcohol having an average degree of polymerization of 1000 to 5000 is preferable.

As the cation-modified polyvinyl alcohol, for example, as described in JP-A-61-10483, primary to tertiary amino groups and quaternary ammonium groups are added to the main chain or side chains of polyvinyl alcohol. It is a polyvinyl alcohol in the chain.

Further, other hydrophilic polymers can be used in combination, but the content is 20% by mass based on polyvinyl alcohol.
It is preferably not more than the degree.

In the present invention, the mass ratio of the hydrophilic polymer to the inorganic fine particles in the porous ink-receiving layer is determined mainly by the transparency of the ink-receiving layer, the ink absorbency and the surface strength, but generally 100 / 60 to 100/8,
It is preferably in the range of 100/50 to 100/15.
When the ratio of the inorganic fine particles to the hydrophilic polymer is increased, the ink absorbability is improved, but the transparency is lowered, cracks are likely to occur during drying, the surface strength is lowered, and the powder is likely to fall off. On the contrary, when the ratio is lowered, the transparency and the surface strength are improved, but the ink absorption is lowered.

The surfactants used in the present invention include, as cationic surfactants, aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts and the like. , As amphoteric surfactants, carboxybetaine type, aminocarboxylic acid salts, imidazolinium betaine, lecithin, etc., as nonionic surfactants, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene sorbitan Fatty acid ester,
One or more kinds are appropriately selected from polyethylene glycol fatty acid ester, sucrose fatty acid ester, fatty acid alkanolamide and the like. Anionic surfactants such as carboxylic acid salts and sulfonic acid salts can be used, but the amount is limited due to their cohesiveness with the ink receiving layer composition. Above all, the HLB value is 3 to 8 in order to adjust the contact angle with linseed oil.
The above-mentioned surfactants are preferably selected.

The ink receiving layer of the present invention preferably contains a cationic compound. Examples of the cationic compound used in the present invention include a cationic polymer and a water-soluble metal compound used for the purpose of improving water resistance. The cationic polymer tends to lower the transparency when used in combination with the vapor-phase method silica, but the water-soluble metal compound suppresses the generation of fine cracks and conversely improves the transparency. Therefore, in the present invention, the gas-phase method silica and the water-soluble metal compound have good ink absorbability and water resistance,
It has the advantage of high transparency.

Examples of the cationic polymer used in the present invention include polyethyleneimine, polydiallylamine, polyallylamine, JP-A-59-20696 and 59-59.
33176, 59-33177, 59-155.
No. 088, No. 60-11389, No. 60-49990.
No. 60-83882, No. 60-109894,
62-198493, 63-49478, 6
3-115780, 63-280681, JP-A-1-40371, 6-234268, 7-12.
Polymers having a primary to tertiary amino group and a quaternary ammonium salt group described in JP 5411, 10-193776 and the like are preferably used. The molecular weight of these cationic polymers is 5,000 or more, and further 5,000 to
About 100,000 is preferable.

The amount of these cationic polymers used is 1 to 10% by mass, preferably 2 to 7% by mass, based on the inorganic fine particles.

Examples of the water-soluble metal compound used in the present invention include water-soluble polyvalent metal salts. Examples thereof include water-soluble salts of metals selected from calcium, barium, manganese, copper, cobalt, nickel, aluminum, iron, zinc, zirconium, chromium, magnesium, tungsten and molybdenum. Specifically, for example, calcium acetate, calcium chloride, calcium formate, calcium sulfate, barium acetate, barium phosphate, manganese chloride, manganese acetate, manganese formate dihydrate, manganese ammonium sulfate hexahydrate, cupric chloride. , Ammonium chloride copper (II) dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate tetrahydrate, nickel ammonium sulfate hexahydrate Hydrate, nickel amido sulfate tetrahydrate, aluminum sulfate, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate, aluminum chloride hexahydrate, ferrous bromide,
Ferrous chloride, ferric chloride, ferrous sulfate, ferric sulfate, zinc bromide, zinc chloride, zinc nitrate hexahydrate, zinc sulfate, zirconium acetate, zirconium chloride, zirconium chloride octahydrate , Hydroxyzirconium chloride, chromium acetate, chromium sulfate, magnesium sulfate, magnesium chloride hexahydrate, magnesium citrate nonahydrate, sodium phosphotungstate, sodium tungsten citrate, 12 tungstophosphoric acid n hydrate, 12 tungsto Silicic acid 2
Hexahydrate, molybdenum chloride, n-molybdophosphoric acid n-hydrate and the like can be mentioned. A zirconium-based compound is preferable in view of characteristics.

Further, examples of the cationic compound include a basic polyaluminum hydroxide compound which is an inorganic aluminum-containing cationic polymer. The basic polyaluminum hydroxide compound is, for example, [Al ₆ (OH) ₁₅ ]
³⁺ , [Al ₈ (OH) ₂₀ ] ⁴⁺ , [Al ₁₃ (O
H) ₃₄ ] ⁵⁺ , [Al ₂₁ (OH) ₆₀ ] ³⁺ , and the like are water-soluble polyaluminum hydroxides which stably contain basic and polymeric polynuclear condensed ions.

The content of the water-soluble metal compound used in the present invention in the ink receiving layer is 0.1 g / m ² to 10
g / m ^2, and preferably from ^{0.2g / m 2 ~5g / m 2} .

Two or more kinds of the above-mentioned cationic compounds can be used in combination. For example, a cationic polymer and a water-soluble metal compound may be used together.

In the present invention, the ink receiving layer may be hardened with an appropriate hardener for the purpose of improving water resistance and dot reproducibility. Specific examples of the hardener include aldehyde compounds such as formaldehyde and glutaraldehyde, ketone compounds such as diacetyl and chloropentanedione, and bis (2-chloroethylurea) -2-hydroxy-4,6-dichloro-1. , 3,5-triazine,
Compounds having a reactive halogen as described in US Pat. No. 3,288,775, divinyl sulfone, compounds having a reactive olefin as described in US Pat. No. 3,635,718, US Pat. N-methylol compounds as described in US Pat. No. 3,103,43.
Isocyanates such as those described in US Pat.
No. 7,280, 2,983,611, aziridine compounds, US Pat. No. 3,100,704, carbodiimide compounds, US Pat. No. 3,093.
There are epoxy compounds as described in No. 1,537, halogen carboxaldehydes such as mucochloric acid, dioxane derivatives such as dihydroxydioxane, and inorganic hardeners such as chromium alum, zirconium sulfate, boric acid and borate. They may be used alone or in combination of two or more. The amount of the hardener added is 0.01 to 40 with respect to 100 g of the hydrophilic polymer constituting the ink receiving layer.
g is preferable, and more preferably 0.1 to 30 g.

In the present invention, the ink receiving layer further comprises a coloring dye, a coloring pigment, a fixing agent for the ink dye, an ultraviolet absorber, an antioxidant, a pigment dispersant, an antifoaming agent, an organic solvent, a leveling agent, Antiseptic, optical brightener, viscosity stabilizer,
Various known additives such as a pH adjuster can also be added.

The method for applying the ink receiving layer according to the present invention uses various devices such as spin coating, various blade coaters, roll coaters, air knife coaters, bar coaters, rod blade coaters, short dwell coaters and size presses. be able to. Further, after coating or impregnation, finishing may be performed using a calendar such as a machine calendar, a TG calendar, a super calendar, and a soft calendar.

The ink referred to in the present invention means the following colorants,
A recording liquid composed of a liquid medium and other additives.

Examples of the coloring agent include water-soluble dyes or coloring pigments such as direct dyes, acid dyes, basic dyes, reactive dyes and food dyes.

As the ink solvent, water and various water-soluble organic solvents such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol and isobutyl are used. Alkyl alcohols having 1 to 4 carbon atoms such as alcohols; amides such as dimethylformamide and dimethylacetamide; ketones or ketone alcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; polyethylene glycol, polypropylene glycol, etc. Polyalkylene glycols; ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol Le, hexylene glycol,
Examples include alkylene glycols having 2 to 6 alkylene groups such as diethylene glycol; lower alkyl ethers of polyhydric alcohols such as glycerin, ethylene glycol methyl ether, diethylene glycol methyl (or ethyl) ether, and triethylene glycol monomethyl ether. Among these many water-soluble organic solvents, polyhydric alcohols such as diethylene glycol and lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl ether and triethylene glycol monoethyl ether are preferable. Other additives include, for example, a pH adjusting agent, a sequestering agent, an antifungal agent, a viscosity adjusting agent, a surface tension adjusting agent, a wetting agent, a surfactant, and a rust preventive agent.

As an image recording method using the water-based ink according to the present invention, an ink jet method using an ink jet printer is preferable. Further, recording with a commonly used water-based or oil-based pen is also possible.

The constituent elements of the reversible thermosensitive recording layer according to the present invention include a photothermal conversion dye, a leuco dye and a reversible developer.

A reversible thermosensitive recording material in which an image is repeatedly recorded and erased by a near infrared laser beam many times using the photothermal conversion dye according to the present invention requires high heat resistance and laser light resistance. Is. Among the constituent materials of this recording material, the laser light resistance property of the photothermal conversion dye is the most important factor for recording and erasing many times. Specific examples of the photothermal conversion dye used in the present invention include, but are not limited to, phthalocyanine compounds, metal complex compounds, polymethine compounds, and naphthoquinone compounds. Preferable photothermal conversion dyes include phthalocyanine compounds and metal complex compounds in terms of photothermal conversion efficiency, solubility in solvents, dispersibility in resins, and light resistance to ultraviolet light, and phthalocyanine compounds are particularly preferred.

Preferred examples of the phthalocyanine compound are naphthalocyanine compounds, metal-free phthalocyanine compounds, iron phthalocyanine compounds, copper phthalocyanine compounds, zinc phthalocyanine compounds, nickel phthalocyanine compounds, vanadyl phthalocyanine compounds, indium phthalocyanine chloride compounds, tin phthalocyanine compounds and the like. , And more preferably a vanadyl phthalocyanine compound. The phthalocyanine compound used in the present invention may have a substituent on the aromatic ring for the purpose of adjusting absorption wavelength, improving solubility in a solvent, improving light resistance and the like. Examples of the substituent include an alkyl group, an acyl group, an acyloxy group, an aryl group, an alkylamino group, an arylamino group, an arylcarbonylamino group, an alkylether group, an alkylthioether group, an arylether group, an arylthioether group, an amide group, and an amino group. Group, alkyl ester group,
Examples thereof include an aryl ester group, chlorine atom, fluorine atom, cyano group, nitro group, sulfonyl group, sulfonic acid group, pyridyl group and aminocarbonyl group. When the aromatic ring has two or more substituents, they may be the same or different, and the substituents may be bonded to each other to form a ring.

In particular, when the near-infrared absorbing dye is contained in the same layer as the leuco dye and the reversible developer, the solubility or dispersibility in an organic solvent is desired. Therefore, an alkyl group, an alkyl ether group or an alkyl thioether is desired. Group, an aryl ether group, or an aryl thioether group, which is 4 kinds of substituents.
Phthalocyanine compounds having three or more are preferred. As the alkyl group, a linear or branched alkyl group having 4 to 12 carbon atoms is preferable. Further, by having an amide group, an amino group, a nitro group, a chlorine atom, a fluorine atom or the like as a substituent, it is possible to adjust the absorption wavelength and improve light resistance.

Specific examples of the phthalocyanine compound having a vanadyl group include vanadyl phthalocyanine and vanadyl 2,9,16,23-tetra-t-butyl-29.
H, 31H-phthalocyanine, vanadyl 2,9,16,
23-tetraacetyl-29H, 31H-phthalocyanine, vanadyl 2,9,16,23-tetrachloro-29
H, 31H-phthalocyanine, vanadyl 2,9,16,
23-Tetrafluoro-29H, 31H-phthalocyanine, vanadyl 2,9,16,23-tetranitro-29
H, 31H-phthalocyanine, vanadyl 2,9,16,
23-Tetraphenoxy-29H, 31H-phthalocyanine, vanadyl 2,9,16,23-tetraphenoxycarbonyl-29H, 31H-phthalocyanine, vanadyl 2,9,16,23-acetyloxy-29H, 31
H-phthalocyanine, vanadyl 2,9,16,23-acetylamino-29H, 31H-phthalocyanine, vanadyl 2,9,16,23-tetraphenylthio-29
H, 31H-phthalocyanine, vanadyl 2,9,16,
23- (4-pyridylmethoxy) -29H, 31H-phthalocyanine, vanadyl 2,3,9,10,16,1
7,23,24-Octakis (octyloxy) -29
H, 31H-phthalocyanine, vanadyl 2,11,2
0,29-tetra-t-butyl-2,3-naphthalocyanine, vanadyl 3,10,17,24-tetra-t-butyl-1,8,15,22-tetrakis (dimethylamino) -29H, 31H- Phthalocyanine, vanadyl 5,
14,23,32-Tetraphenyl-2,3-naphthalocyanine, vanadyl 5,9,14,18,23,27,
32,36-octabutoxy-2,3-naphthalocyanine, vanadyl 5,9,14,18,23,27,32,
36-octabutylthio-2,3-naphthalocyanine,
Vanadyl phthalocyanine tetrasulfonic acid tetrasodium salt, vanadyl tetrakis (4-cumylphenoxy)
Examples thereof include phthalocyanine, but are not limited thereto.

Specific examples of the leuco dye according to the present invention include the followings, but the present invention is not limited thereto.

3-diethylamino-7-o-chlorophenylaminofluorane, 3-diethylamino-7-m-
Chlorophenylaminofluorane, 3-diethylamino-7-p-chlorophenylaminofluorane, 3-diethylamino-7-o-fluorophenylaminofluorane, 3-diethylamino-7-m-fluorophenylaminofluorane, 3-diethylamino- 7-p-fluorophenylaminofluorane, 3-di-n-butylamino-7-m-chlorophenylaminofluorane, 3-di-n-butylamino-7-p-chlorophenylaminofluorane, 3-di- n-butylamino-7-o-fluorophenylaminofluorane, 3-di-n-butylamino-7-m-fluorophenylaminofluorane, 3-
Di-n-butylamino-7-p-fluorophenylaminofluorane,

3-diethylamino-6-methyl-7-phenylaminofluorane, 3-diethylamino-6-methyl-7-o-chlorophenylaminofluorane, 3-
Diethylamino-6-methyl-7-m-chlorophenylaminofluorane, 3-diethylamino-6-methyl-
7-p-chlorophenylaminofluorane, 3-diethylamino-6-methyl-7-o-fluorophenylaminofluorane, 3-diethylamino-6-methyl-7-
o-Tolylaminofluorane, 3-diethylamino-6
-Methyl-7-m-tolylaminofluorane, 3-diethylamino-6-methyl-7-p-tolylaminofluorane, 3-diethylamino-6-methyl-7-o-trifluoromethylphenylaminofluorane, 3 -Diethylamino-6-methyl-7-m-trifluoromethylphenylaminofluorane, 3-diethylamino-6-methyl-7-p-acetylphenylaminofluorane, 3
-Diethylamino-6-methoxy-7-phenylaminofluorane, 3-diethylamino-6-ethoxy-7-
Phenylaminofluorane,

3-di-n-butylamino-6-methyl-
7-phenylaminofluorane, 3-di-n-butylamino-6-methyl-7-o-tolylaminofluorane,
3-di-n-butylamino-6-methyl-7-m-tolylaminofluorane, 3-di-n-butylamino-6-
Methyl-7-p-tolylaminofluorane, 3-di-n
-Butylamino-6-methyl-7-o-chlorophenylaminofluorane, 3-di-n-butylamino-6-methyl-7-m-chlorophenylaminofluorane, 3-
Di-n-butylamino-6-methyl-7-p-chlorophenylaminofluorane, 3-di-n-butylamino-
6-methyl-7-o-fluorophenylaminofluorane, 3-di-n-butylamino-6-methyl-7-m-
Fluorophenylaminofluorane, 3-di-n-butylamino-6-methyl-7-p-fluorophenylaminofluorane, 3-di-n-butylamino-6-methyl-7-o-trifluoromethylphenyl Aminofluorane, 3-di-n-butylamino-6-methyl-7-m-
Trifluoromethylphenylaminofluorane, 3-di-n-butylamino-6-methyl-7-p-trifluoromethylphenylaminofluorane, 3-di-n-butylamino-6-methoxy-7-phenylamino Fluorane, 3-di-n-butylamino-6-ethoxy-7-phenylaminofluorane,

3-di-n-pentylamino-6-methyl-7-phenylaminofluorane, 3-di-n-pentylamino-6-methyl-7-m-trifluoromethylphenylaminofluorane, 3- Pyrrolidyl-6-methyl-7-phenylaminofluorane, 3-piperidyl-6
-Methyl-7-phenylaminofluorane, 3-N-methyl-N-isopentylamino-6-methyl-7-phenylaminofluorane, 3-N-methyl-N-cyclohexylamino-6-methyl-7- Phenylaminofluorane, 3-N-methyl-N-n-butylamino-6-methyl-7-phenylaminofluorane, 3-N-methyl-N-n-propylamino-6-methyl-7-phenylamino Fluorane, 3-N-ethyl-N-isopentylamino-6-methyl-7-phenylaminofluorane,
3-N-ethyl-N-isopentylamino-6-methyl-7-o-chlorophenylaminofluorane, 3-N-
Ethyl-N-p-tolylamino-6-methyl-7-phenylaminofluorane, 3-N-ethyl-N- (4-ethoxybutyl) amino-6-methyl-7-phenylaminofluorane, 3-diethylamino- 7-dibenzylaminofluorane, 3-diethylamino-7-octylaminofluorane, 3-diethylamino-7-phenylfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-6-chloro-7-methyl Fluorane, 3-diethylamino-7- (3,4-dichloroanilino) fluorane, 3-diethylamino-7- (2
-Chloroanilino) fluoran,

3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (crystal violet lactone), 3,3-bis (p-dimethylaminophenyl) phthalide, 3- (p-dimethylaminophenyl) ) -3- (1,2-Dimethylindol-3-yl)
Phthalide, 3- (p-dimethylaminophenyl) -3-
(2-Methylindol-3-yl) phthalide, 3-
(P-Dimethylaminophenyl) -3- (2-phenylindol-3-yl) phthalide, 3,3-bis (1,
2-Dimethylindol-3-yl) -5-dimethylaminophthalide, 3,3-bis (1,2-dimethylindol-3-yl) -6-dimethylaminophthalide, 3,
3-bis (9-ethylcarbazol-3-yl) -5-
Dimethylaminophthalide, 3,3-bis (2-phenylindol-3-yl) -5-dimethylaminophthalide, 3-p-dimethylaminophenyl-3- (1-methylpyrrol-2-yl) -6 -Dimethylaminophthalide,

3- (2-Ethoxy-4-aminophenyl) -3- (1-ethyl-2-methylindole-3-
Yl) -4-azaphthalide, 3- (2-ethoxy-4-)
Methylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3-
(2-Ethoxy-4-ethylaminophenyl) -3-
(1-Ethyl-2-methylindol-3-yl) -4
-Azaphthalide, 3- (2-ethoxy-4-propylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-ethoxy-4-hexylaminophenyl) ) -3- (1-Ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-ethoxy-4-dimethylaminophenyl) -3- (1-ethyl-2-methylindole-3) −
Yl) -4-azaphthalide, 3- (2-ethoxy-4-)
Diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3-
(2-Ethoxy-4-dipropylaminophenyl) -3
-(1-Ethyl-2-methylindol-3-yl)-
4-azaphthalide, 3- (2-ethoxy-4-dihexylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-
Ethoxy-4-phenylaminophenyl) -3- (1-
Ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-ethoxy-4-pyridylphenyl) -3- (1-ethyl-2-methylindol-3-
Yl) -4-azaphthalide, 3- (3-ethoxy-4-)
Diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide,

3- (2-Methyl-4-diethylaminophenyl) -3- (1-ethyl-2-methylindole-
3-yl) -4-azaphthalide, 3- (2-ethyl-4)
-Diethylaminophenyl) -3- (1-ethyl-2-
Methylindol-3-yl) -4-azaphthalide, 3
-(2-propyl-4-diethylaminophenyl) -3
-(1-Ethyl-2-methylindol-3-yl)-
4-Azaphthalide, 3- (2-butyl-4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-pentyl-4-diethylaminophenyl) -3- (1-Ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-hexyl-4-diethylaminophenyl) -3- (1-ethyl-2-methylindole-3-
Yl) -4-azaphthalide, 3- (2-cyclohexyl-4-diethylaminophenyl) -3- (1-ethyl-
2-Methylindol-3-yl) -4-azaphthalide, 3- (2-cyano-4-diethylaminophenyl)
-3- (1-Ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-nitro-4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) ) -4-Azaphthalide, 3- (2
-Chloro-4-diethylaminophenyl) -3- (1-
Ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-bromo-4-diethylaminophenyl) -3- (1-ethyl-2-methylindole-3
-Yl) -4-azaphthalide, 3- (2-methyl-4-)
Diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3-
(2-Ethoxy-4-diethylaminophenyl) -3-
(2-Methylindol-3-yl) -4-azaphthalide, 3- (2-ethoxy-4-diethylaminophenyl) -3- (1-methyl-2-methylindol-3-
Yl) -4-azaphthalide, 3- (2-ethoxy-4-)
Diethylaminophenyl) -3- (1-propyl-2-
Methylindol-3-yl) -4-azaphthalide, 3
-(2-Ethoxy-4-diethylaminophenyl) -3
-(1-Butyl-2-methylindol-3-yl)-
4-azaphthalide, 3- (2-ethoxy-4-diethylaminophenyl) -3- (1-pentyl-2-methylindol-3-yl) -4-azaphthalide,

3- (2-Ethoxy-4-diethylaminophenyl) -3- (1-hexyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-ethoxy-4-diethylaminophenyl)- 3- (1-heptyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-ethoxy-4-diethylaminophenyl) -3- (1-octyl-2-methylindole-3
-Yl) -4-azaphthalide, 3- (2-ethoxy-4)
-Diethylaminophenyl) -3- (1-nonyl-2-
Methylindol-3-yl) -4-azaphthalide, 3
-(2-Ethoxy-4-diethylaminophenyl) -3
-(1-Isopropyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-ethoxy-4-diethylaminophenyl) -3- (1-isobutyl-2-
Methylindol-3-yl) -4-azaphthalide, 3
-(2-Ethoxy-4-diethylaminophenyl) -3
-(1-Isopentyl-2-methylindol-3-yl) -4-azaphthalide,

3- (2-Ethoxy-4-diethylaminophenyl) -3- (1-methyl-2-ethylindol-3-yl) -4-azaphthalide, 3- (2-ethoxy-4-diethylaminophenyl)- 3- (1-ethyl-
2-Propylindol-3-yl) -4-azaphthalide, 3- (2-ethoxy-4-diethylaminophenyl) -3- (1-ethyl-2-butylindol-3-
Yl) -4-azaphthalide, 3- (2-ethoxy-4-)
Diethylaminophenyl) -3- (1-ethyl-2-pentylindol-3-yl) -4-azaphthalide, 3
-(2-Ethoxy-4-diethylaminophenyl) -3
-(1-Ethyl-2-hexylindol-3-yl)
-4-azaphthalide, 3- (2-ethoxy-4-diethylaminophenyl) -3- (1-ethyl-2-isopropylindol-3-yl) -4-azaphthalide, 3-
(2-Ethoxy-4-diethylaminophenyl) -3-
(1-Ethyl-2-isobutylindol-3-yl)
-4-azaphthalide, 3- (2-ethoxy-4-diethylaminophenyl) -3- (1-ethyl-2-phenylindol-3-yl) -4-azaphthalide,

4,4'-bis (dimethylaminophenyl) benzhydryl benzyl ether, N-chlorophenyl leuco auramine, N-2,4,5-trichlorophenyl leuco auramine, benzoyl leuco methylene blue, p-nitrobenzoyl leuco Methylene blue, 3
-Methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3,3'-dichlorospirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-methylnaphtho- (3-methoxybenzo) spiropyran, 3-propylspiro Examples thereof include benzopyran.

The above leuco dyes may be used either individually or in combination of two or more. In addition, toning can be performed by mixing a leuco dye that develops another hue.

The reversible color developer according to the present invention is preferably a compound represented by the following general formula (1), but the present invention is not limited thereto.

[0055]

[Chemical 1]

In the compound represented by the general formula (1), X ¹ and X ² may be the same or different, and each does not contain an oxygen atom, a sulfur atom or a hydrocarbon atomic group at both ends. -Represents a divalent group having a bond as a minimum structural unit. R ¹ represents a single bond or a divalent hydrocarbon group having 1 to 12 carbon atoms. R ² represents a divalent hydrocarbon group having 1 to 18 carbon atoms. Preferred is a divalent hydrocarbon group having 1 to 4 carbon atoms. R ³ represents a monovalent hydrocarbon group having 1 to 24 carbon atoms, preferably a hydrocarbon group having 6 to 24 carbon atoms, and more preferably a hydrocarbon group having 8 to 24 carbon atoms. Furthermore, the sum of carbon numbers of R ¹ , R ² and R ³ is 11 or more and 3
The case of 5 or less is particularly preferable. R ¹ , R ² and R ³ mainly represent an alkylene group and an alkyl group, respectively. R
^In the case of ¹ , it may contain an aromatic ring. f is 0 to 4
R ² and X ^{2 which} are repeated when f is 2 or more may be the same or different.

X ¹ and X ² in the general formula (1) include a divalent group having a minimum constitutional unit of a —CONH— bond which does not contain a hydrocarbon atom group at both ends, and specific examples thereof include Diacylamine (-CONHCO-), diacylhydrazine (-CONHNHCO-), oxalic acid diamide (-NH
COCONH-), acyl urea (-CONHCONH
-, -NHCONHCO-), semicarbazide (-NH
CONHNH-, -NHNHCONH-), acyl semicarbazide (-CONHNHCONH-, -NHCON)
HNHCO-), diacylaminomethane (-CONHC
H ₂ NHCO -), 1- acylamino-1- Ureidometan (-CONHCH ₂ NHCONH -, - NHCON
HCH ₂ NHCO-), malonamide (-NHCOCH
₂ CONH-), 3-acylcarbazic acid ester (-
Examples thereof include groups such as CONHNHCOO- and -OCONHNHCO-, but diacylhydrazine, oxalic acid diamide, and acyl semicarbazide are preferable.

Specific examples of the reversible color developer according to the present invention include the following structural formulas (1-1) to (1-1)
However, the present invention is not limited to this.

[0059]

[Chemical 2]

[0060]

[Chemical 3]

Among the specific examples of the reversible color developer, particularly preferable compounds are (1-3), (1-4), (1-6) and (1
-9) and (1-16).

The reversible color developer according to the present invention is 1
One kind or a mixture of two or more kinds may be used, and the amount used is usually 5 to 5,000 with respect to a colorless or pale leuco dye.
It is mass%, preferably 10 to 3000 mass%.

Next, a specific method for producing the reversible thermosensitive recording layer according to the present invention will be described, but the present invention is not limited thereto.

Specific examples of the method for producing the reversible thermosensitive recording layer according to the present invention include a colorless or pale leuco dye, a reversible developer, and a photothermal conversion dye as main components, which are coated on a support. Alternatively, a method of printing to form a reversible thermosensitive recording layer can be mentioned.

Usually, a colorless or light-colored leuco dye, a reversible color developer, and a photothermal conversion dye are contained in the reversible thermosensitive recording layer after each compound is dissolved in a solvent or dispersed in a dispersion medium. A method of mixing, a method of dissolving each compound in a solvent or dispersing in a dispersion medium, mixing each compound by heating to dissolve and homogenize, and then cooling.
A layer can be formed by preparing a mixed solution by a method of dissolving it in a solvent or dispersing it in a dispersion medium, and coating or printing it on a support and then drying it.

When the photothermal conversion dye is contained in a layer different from that of the leuco dye and the reversible developer, the photothermal conversion dye is dispersed alone or together with a binder in a layer adjacent to the layer containing the reversible developer. It is preferable to contain

It is also possible to add a binder to the reversible thermosensitive recording layer for the purpose of improving the strength of the reversible thermosensitive recording layer. Specific examples of the binder include starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, sodium polyacrylate, acrylic acid amide / acrylic acid ester copolymer, acrylic acid amide / acrylic. Acid ester / methacrylic acid terpolymer, alkali salt of styrene / maleic anhydride copolymer, alkali salt of ethylene / maleic anhydride copolymer, polyvinyl acetate, polyurethane, polyacrylic ester, styrene / butadiene copolymer Polymer, acrylonitrile / butadiene copolymer,
Methyl acrylate / butadiene copolymer, ethylene / vinyl acetate copolymer, ethylene / vinyl chloride copolymer, polyvinyl chloride, ethylene / vinylidene chloride copolymer, polyvinylidene chloride, polycarbonate, polyvinyl butyral and the like can be mentioned. The role of these binders is
The purpose is to keep each material of the composition uniformly dispersed by applying heat for printing and erasing without deviation. Therefore, it is preferable to use a resin having high heat resistance as the binder resin. Recently, high value-added information recording media such as prepaid cards and stored cards are often used, and along with this, high durability products such as heat resistance, water resistance, and adhesiveness are required. Is coming. Curable resins are particularly preferable for such requirements.

Examples of the curable resin include a thermosetting resin, an electron beam curing resin, an ultraviolet curing resin and the like.
As the thermosetting resin, for example, phenoxy resin, polyvinyl butyral resin, cellulose acetate propionate resin and the like, which are cured by reacting a hydroxyl group and a carboxyl group with a crosslinking agent, can be mentioned. Examples of the crosslinking agent at this time include isocyanates, amines, phenols, epoxies and the like.

Monomers used for electron beam and ultraviolet ray curable resins include monofunctional monomers represented by acrylics, bifunctional monomers, polyfunctional monomers and the like. In particular, in the case of ultraviolet crosslinking, photopolymerization initiation Agents and photopolymerization accelerators are used.

The problem was that the heat energy applied to the reversible thermosensitive recording layer discolored the image recorded on the ink receiving layer. It has been found that the problem can be solved by providing it between the layer containing the dye and the second invention. Further, it is more preferable to contain an ultraviolet absorber for the purpose of improving the light resistance of the leuco dye and the photothermal conversion dye. Moreover, you may contain at least one of an organic pigment and an inorganic pigment as needed.

Specific examples of the synthetic resin used in the heat insulating layer according to the present invention include polyolefin resins such as polycarbonate, epoxy resin, polyethylene, polypropylene, TPX, polyester resin, polyamide resin, polyvinyl acetate, styrene vinyl acetate. Copolymer resin, acrylic resin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl ether, polyvinyl ketone, polyether, polyvinyl alcohol resin,
In addition to synthetic resin materials such as diene resins and polyurethane resins, the compounds exemplified as the binder used in the reversible thermosensitive recording layer can be used. Insulation layer is 0.5μ
It is preferably provided in the range of m to 30 μm, and more preferably 1 to 25 μm.

For the purpose of preventing aging of the reversible thermosensitive recording layer, an antioxidant used in rubber products and the like can be added. Further, an antioxidant may be contained in the upper layer or the lower layer of the reversible thermosensitive recording layer. For the purpose of preventing the deterioration of the photothermal conversion dye due to ultraviolet rays, an antiaging agent may be contained in the layer containing the photothermal conversion dye or the upper layer of the layer containing the photothermal conversion dye. Antiaging agents include p, p'-diaminodiphenylmethane, aldol-α-naphthylamine, N, N'-diphenyl-
Examples thereof include amine compounds such as p-phenylenediamine, hydroquinone monobenzyl ether, phenol compounds such as 1,1-bis (p-hydroxyphenyl) cyclohexane, benzotriazole compounds, triazine compounds, benzophenone compounds, and benzoic acid esters. Other examples include o-phenylene thiourea, zinc salt of 2-aminobenzimidazole, nickel dibutylthiocarbamate, zinc oxide, paraffin and the like. Further, a polymer containing such a monomer having an antioxidant structure as one component of polymerization, or a polymer having a polymer main chain grafted with an antioxidant structure can also be used. It is also possible to use two or more anti-aging agents in combination.

A heat-fusible substance may be contained in the reversible thermosensitive recording layer as an additive for controlling the color developing sensitivity and the decoloring temperature of the reversible thermosensitive recording layer. 60 ° C
Those having a melting point of ~ 200 ° C are preferable, and especially 80 ° C.
Those having a melting point of ˜180 ° C. are preferred. It is also possible to use a sensitizer which is used for general thermal recording paper. For example, waxes such as N-hydroxymethylstearic acid amide, stearic acid amide, and palmitic acid amide, naphthol derivatives such as 2-benzyloxynaphthalene, biphenyl derivatives such as p-benzylbiphenyl and 4-allyloxybiphenyl, 1,2, and the like. -Polyether compounds such as -bis (3-methylphenoxy) ethane, 2,2'-bis (4-methoxyphenoxy) diethyl ether, bis (4-methoxyphenyl) ether, diphenyl carbonate, dibenzyl oxalate, bis (oxalate) Carbonic acid such as p-methylbenzyl) ester or an oxalic acid diester derivative or the like can be added in combination.

Examples of the support according to the present invention include paper, non-woven fabric, synthetic resin, synthetic paper, metal plate, metal plate, glass and the like. As the synthetic resin material, polycarbonate,
Epoxy resin, polyethylene, polypropylene, TPX
Polyolefin resin, polyester resin, polyamide resin, polyvinyl acetate, styrene-vinyl acetate copolymer resin, acrylic resin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl ether, polyvinyl ketone, polyether, polyvinyl alcohol resin A synthetic resin material such as a diene resin or a polyurethane resin can be used. These synthetic resin materials may be used as they are, or may be blended and used, or may be kneaded with a pigment and used, for example, as a white plastic sheet. Paper, various non-woven fabrics, woven fabrics, synthetic resin films, synthetic resin laminated paper, synthetic paper, metal foil, a composite sheet combining glass, etc. can be arbitrarily used according to the purpose, and further,
It may be transparent, semi-transparent or opaque. Moreover, it is not limited to these. When an optical disk is used as the support, polycarbonate is preferable from the viewpoint of moisture resistance and dimensional stability.

The layer structure of the information recording medium according to the present invention is as follows:
An intermediate layer may be provided between the reversible thermosensitive recording layer and the support. In this case, the protective layer and the intermediate layer may be composed of a plurality of layers of 2 layers or 3 layers or more. Further, in the reversible thermosensitive recording layer, a material capable of electrically, magnetically and optically recording information may be contained in another layer, a surface on which the reversible thermosensitive recording layer is provided or an opposite surface. . Also, curling is prevented on the surface opposite to the surface on which the reversible thermosensitive recording layer is provided,
A back coat layer may be provided for the purpose of antistatic.

For the reversible thermosensitive recording layer, protective layer and intermediate layer, diatomaceous earth, talc, kaolin, calcined kaolin,
Pigments such as calcium carbonate, magnesium carbonate, titanium oxide, zinc oxide, silicon oxide, aluminum hydroxide, and urea-formalin resin, as well as higher fatty acid metal salts such as zinc stearate and calcium stearate, paraffin, paraffin oxide, polyethylene, Waxes such as oxidized polyethylene, stearic acid amide, and castor wax, dispersants such as sodium dioctylsulfosuccinate, surfactants, fluorescent dyes, and the like can be included.

The method for recording / erasing an image on the reversible thermosensitive recording layer according to the present invention includes laser irradiation energy capable of developing a leuco dye without causing ablation, regardless of the amount of the photothermal conversion dye contained. By erasing by irradiating with a laser beam having an energy of 25% or more and 65% or less, it is possible to repeatedly record and erase an image with a clear contrast many times. The more preferable erasing energy is 30% or more and 50% or less of the laser irradiation energy that can develop the leuco dye without causing ablation, and by using the energy in this range, the image can be recorded more times. Record
I found that I can erase.

As a method of changing the irradiation energy of the laser light used for recording and erasing, a method of changing the irradiation time of the laser light while keeping the laser output constant, a method of changing the laser output itself, and moving the focus of the laser. There is a method of changing the laser energy reaching the recording surface by a method, a method of applying a filter, or the like. According to the study of the present inventors, among these, a method of changing the laser energy reaching the recording surface by changing the irradiation time of the laser beam while keeping the laser output constant, recording an image many times It is preferable because erasing can be realized at a higher level. When the laser output is kept constant, by setting the laser light irradiation time during erasing within the range of 25% or more and 65% or less of the laser light irradiation time required for coloring the leuco dye, the energy applied to the unit area is set to 25 It can be set in the range of from% to 65%. High-speed erasing is possible by shortening the laser light irradiation time without reducing the laser output.

As a method for changing the laser irradiation time, there is a method for changing the laser scanning speed. When the laser output is constant, the laser light irradiation time can be set to 25% or more and 63% or less by setting 1.6 times or more and 4 times or less of the laser scanning speed required for coloring the leuco dye. .

As a method for erasing an image with a pulse laser, the laser output and the number of spots in a unit area are kept constant, and the time (pulse width) for irradiating one spot with the laser light is changed to obtain a laser beam in a unit area. The irradiation time can be adjusted. The pulse width during erasing should be 25% or more of the pulse width required for coloring the leuco dye 65
The laser light irradiation time can be set to 25% or more and 65% or less by setting the ratio to be% or less.

Further, by making the laser output and the pulse width constant and reducing the number of spots of the laser light, the laser light irradiation time per unit area can be shortened. In this case, the laser light irradiation time can be set to 25% or more and 65% or less by setting the number of spots to 25% or more and 65% or less of the number of spots required for coloring the leuco dye. The number of spots can be changed by irradiating every few spots with a laser beam, irradiating every few lines with a laser beam, or by combining these spots of laser light radiated per unit area. The number of can be changed. In order to reduce unevenness when erasing an image, it is preferable to irradiate a laser beam with a regular pattern.

The method for adjusting the laser light irradiation time may be a combination of the above methods. For example, the erasing energy can be set to 25% of the laser irradiation energy during image formation by setting the pulse width during erasing to 50% during image formation and the number of spots to 50% during image formation.

In the present invention, a preferable example of the near infrared laser used for recording and erasing an image is 740n.
a semiconductor laser having a light emitting region at m to 910 nm or 90
A YAG laser having an emission region of 0 nm to 1500 nm can be used. In the case of image erasing, since the colored leuco dye is irradiated with laser light, it is more preferable to use laser light of 800 nm or more for the purpose of reducing deterioration of the leuco dye. In addition, since many dyes that are stable and can efficiently convert laser light into heat have a wavelength of 1200 nm or less,
It is more preferable to use laser light having a wavelength of 00 nm or more and 1200 nm or less.

The amount of the photothermal conversion dye used is preferably set so that the absorbance at the oscillation wavelength of the light source used is 0.2 or more. If the amount is less than this amount, the energy required to obtain sufficient heat is increased. On the other hand, the photothermal conversion dye also has some absorption in the visible region, and if the amount used is too large, the contrast is lowered. 400 nm
It is preferable to set the upper limit of the amount of the photothermal conversion dye used so that an average transmittance of 60 to 700 nm can be secured at 60% or more. Two or more kinds of photothermal conversion dyes can be mixed and used.

The photothermal conversion dye is preferably contained in at least one of the same layer and an adjacent layer with respect to the layer containing the leuco dye and the reversible developer, and it is contained in the same layer. Is more preferable for obtaining good sensitivity.

[0086]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In addition, the number of copies in the examples is based on mass.

Example 1 [Preparation of reversible thermosensitive recording material] 3-diethylamino-6
-Methyl-7-m-trifluoromethylphenylaminofluoran (Yamada Chemical Co., Ltd., BLACK 100)
20 parts, N- [3- (p-hydroxyphenyl) propiono] -N'-n-docosanohydrazide 100 parts, polyester polyol (manufactured by Dainippon Ink and Chemicals, Inc.,
50 parts of Vernock D-293-70), 50 parts of a curing agent (Nippon Polyurethane Co., Ltd., Coronate HL), 300 parts of methyl ethyl ketone, and 300 parts of toluene, vanadyl 2,11,20,29-tetra-t as a photothermal conversion dye. −
1 part of butyl-2,3-naphthalocyanine was added, and the mixture was pulverized with glass beads for 5 hours on a paint shaker to obtain a dispersion liquid. The above dispersion liquid was applied to a polyethylene terephthalate (25 μm transparent PET) sheet to give a solid content of 7 g /
It was coated so as to have a size of m ^2, and dried to obtain a reversible thermosensitive recording layer. Next, 10 parts of tinuvin, polyester polyol (manufactured by Dainippon Ink and Chemicals, Inc., Burnock D-293-)
70) 50 parts, curing agent (Nippon Polyurethane Co., Ltd., Coronate HL) 50 parts, methyl ethyl ketone 300 parts,
300 parts of toluene was crushed together with glass beads for 5 hours with a paint shaker to obtain a dispersion of a heat insulating layer. This liquid
The reversible thermosensitive recording layer was coated so that the solid content was 10 g / m ^2, and dried to obtain a heat insulating layer. Next, 95 parts of vapor phase silica (average particle size 0.2 μm), wet silica (Nipseal E-220A manufactured by Nippon Silica Co., Ltd.), 3 parts of dimethyldiallylammonium chloride homopolymer, 4 parts of boric acid, polyvinyl alcohol ( A mixture of 88% of kettle, 20 parts of an average degree of polymerization of 3500), 1 part of a surfactant and 2 parts of zirconium acetate was prepared to a solid content concentration of 10% so as to obtain a concentration of 15 g / m ² . After coating and drying, an ink receiving layer was provided to obtain the information recording medium of Example 1.

[Recording by Inkjet Method] An adhesive was spray-coated on the surface opposite to the ink receiving layer of the information recording medium of Example 1 and bonded to PPC paper, and then red, blue, and Images of yellow and green were formed, and it was confirmed that the image did not bleed by dripping water droplets on the image area.

[Recording by Laser Light] Ink jet recording part and unrecorded part have oscillating wavelength of 830n.
m, an output of 1 W, and a continuous wave semiconductor laser were used to form an image by adjusting the scanning speed to a speed capable of forming an image under irradiation conditions of a spot system of 50 μm. Next, laser light was irradiated under the condition that the scanning speed was increased to erase the image previously recorded by the laser light. Similarly, recording and erasing with laser light were repeated 100 times. As a result, it was confirmed that the recording and erasing could be performed with clear contrast even after 100 times of repeated tests.

Example 2 An information recording medium of Example 2 was obtained in the same manner except that an ink receiving layer was provided directly on the reversible thermosensitive recording layer without providing a heat insulating layer. When evaluated in the same manner as in Example 1, the results up to the 50th repetition were the same as in Example 1. 100
A slight discoloration was observed in the inkjet recorded image after the second repeated test.

Example 3 A commercially available CD-R (manufactured by Taiyo Yuden Co., Ltd., 7 was coated with an adhesive on the side opposite to the ink receiving layer of the information recording medium of Example 1.
The information recording medium of Example 3 was obtained by adhering it to the surface opposite to the writing / reading surface (00 MB). A repeated test was conducted in the same manner as in Example 1 except that an image was directly formed using an inkjet printer without being stuck to a PPC paper. As a result, the same result as in Example 1 was obtained. Next, the CD-R of Example 3 was set in the CD-R drive and 10 MB of information was written / read. As a result, it was possible to write / read information without generating an error.

[0092]

According to the present invention, there is provided an information recording medium capable of forming an image using an aqueous ink and forming / erasing an image by heat generated by irradiating a laser beam.

Claims (2)

[Claims] 1. A reversible thermosensitive recording layer containing a normally colorless or light-colored leuco dye, a photothermal conversion dye, and a reversible developer that develops the color of the leuco dye by heating and reheats it to decolorize it. An information recording medium provided with at least one ink receiving layer. 2. The information recording medium according to claim 1, wherein at least one heat insulating layer is provided between the ink receiving layer and the layer containing a photothermal conversion dye.