JPH10104781A - Heat developable photosensitive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high sharpness thin heat developable photosensitive material with a colored layer having aging stability and excellent in decolorability at the time of heating while using reduced amts. of additives. SOLUTION: This heat developable photosensitive material has a colored layer decolorable by heating and contg. at least a dye decolorable by cycloaddition reaction on the substrate and holds a decoloring agent that causes cycloaddition reaction with the dye and decolors the dye on the substrate, this material has a sheet including a colored layer contg. at least a dye decolorable by cycloaddition reaction and a sheet contg. at least a decoloring agent that causes cycloaddition reaction with the dye and decolors the dye, or this material has a colored layer contg. at least photosensitive silver halide and a dye decolorable by cycloaddition reaction on the substrate and holds a decoloring agent that causes cycloaddition reaction with the dye and decolors the dye on the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a photothermographic material. More specifically, the present invention relates to a photothermographic material having, on a support, a colored layer which is easily decolored by heat treatment.

[0002]

2. Description of the Related Art In a photothermographic material, a light-sensitive silver halide emulsion layer or another layer is often colored in order to absorb light of a specific wavelength.

For example, when it is necessary to control the spectral composition of light to be incident on a silver halide emulsion layer, a coloring layer is provided on a side farther from a support than an emulsion on a photographic material. Such a colored layer is also called a filter layer. When there are a plurality of photographic emulsion layers such as a multilayer color light-sensitive material, a filter layer may be located between them.

Light scattered when passing through or after passing through the emulsion layer is reflected on the interface between the emulsion layer and the support or on the surface of the photosensitive material on the side opposite to the emulsion layer and reenters the emulsion layer. For the purpose of preventing image blurring due to the phenomenon, that is, halation, a colored layer is provided between the emulsion layer and the support or on the surface of the support opposite to the emulsion layer. Such a colored layer is called an antihalation layer. In the case of multilayer color photosensitive material,
An antihalation layer may be placed between the layers.

Further, in order to prevent a decrease in image sharpness due to light scattering in the emulsion layer (this phenomenon is generally called irradiation), the emulsion layer is colored.

In the case of a photothermographic material which is usually processed at 100 ° C. to 200 ° C. by simple heating for a short time, these colored layers, ie, an antihalation layer, an anti-irradiation layer, and a filter layer are subjected to heat development conditions. It is necessary to completely decolorize under or after heating conditions. Also,
These dyes must be photochemically inert. That is, it is essential that the performance of the silver halide emulsion layer is not adversely affected in a chemical sense, such as a decrease in sensitivity, a regression of a latent image, or a fog.

As a system for decoloring by heat treatment in a heat development system, for example, US Pat. No. 3,745,099
No. 3615432, No. 4033948, No. 40
No. 88497, No. 4196002, No. 4153463
Nos. 4,197,131, 4,283,487, JP-A-59-182436 and JP-A-3-26765. However, these methods require a large amount of an excessive decoloring agent to completely decolorize the film, increase the film thickness, color the reaction product, or adversely affect the silver halide. There were problems such as the effect.

[0008]

SUMMARY OF THE INVENTION The present invention addresses these prior art problems. That is, an object of the present invention is to provide a photothermographic material having a colored layer that is stable over time and excellent in decolorability during heat treatment.

Another object of the present invention is to provide a photothermographic material having high sharpness.

It is a further object of the present invention to provide a photothermographic material having a small film thickness and a small amount of added material.

[0011]

The above object has been attained by the following constitutions. (1) In a photothermographic material having a colored layer which is decolorized by heat treatment, the colored layer contains at least a dye which is decolorized by a cycloaddition reaction, and causes a cycloaddition reaction with the dye on the support. Photothermographic material having a decoloring agent for decoloring. (2) In a photothermographic material having on a support a colored layer that is decolorized by heat treatment, the colored layer contains at least a dye that is decolorized by a cycloaddition reaction, and is on a support different from the support. A photothermographic material comprising at least a decolorant capable of causing a cycloaddition reaction with a dye to decolor. (3) In a photothermographic material having a colored layer decolorizable by heat treatment on a support, a color layer containing at least photosensitive silver halide, a dye decolorable by a cycloaddition reaction, is provided on the support. A photothermographic material having a decoloring agent that causes a cycloaddition reaction with a dye to decolor.

The idea of using a dye that decolorizes by a cyclization addition reaction as a halation / irradiation preventing layer or a filter layer of a photothermographic material and reacting it with a decoloring agent by heat treatment to decolorize it. Is not known at all.

[0013]

DETAILED DESCRIPTION OF THE INVENTION The cycloaddition reaction of the present invention refers to a cup of two unsaturated molecules having one or more (conjugated) unsaturated bonds as generally known in organic chemistry. 3 shows a ring reaction. For example, a 1,2-cycloaddition reaction, a 1,3-cycloaddition reaction, a 1,4-cycloaddition reaction and the like can be mentioned, and specifically, [2 + 2], [4 + 2], [4+
4] and the like, an ene reaction, a 1,3-dipolar cycloaddition reaction, and the like. In the present invention, a thermal [4 + 2] cycloaddition, that is, a Diels-Alder reaction is preferable, and a combination of a diene part of a decolorizable dye and a double bond of a decolorant is more preferable.

As the dye which can be used in the present invention, there can be used compounds which directly or indirectly undergo a cyclization addition reaction to cause the π-conjugated system involved in the main absorption of the dye to be cleaved and decolored. Dye Handbook, edited by the Society of Organic Chemistry, 1970, "Chemistry of Functional Dyes", CMC1
981 published, "Functional dyes" Kodansha 1992 published,
`` Dienes in the Diels-Alder reaction '', John Wiley
& Sons, Inc., 1990, `` Hetero Diels-Alder metho
dology in organic Synthesis '', Academic Press, IN
C., 1987, etc., polymethine dyes, azomethine dyes, azo dyes, various cyanine dyes, carbonium dyes, stilbene dyes, quinone dyes, anthracene dyes, naphthacene dyes, pentacene dyes, tetrazine dyes, isobenzofuran Known dyes such as dyes, isoindole dyes, oxopyran dyes, tropone dyes, cyclopentadienone dyes, and fulvene dyes can be used. Among these compounds, 1,3-substituted isobenzofurans and cyclones as shown in the following general formulas (1) and (2) are particularly preferably used.

[0015]

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[0016]

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In the above general formula (1), R1, R2, R
3 and R4 are each a hydrogen atom, a halogen atom, preferably an alkyl group having 1 to 32 carbon atoms, preferably an alkenyl group having 2 to 32 carbon atoms, and preferably 7 to 18 carbon atoms.
Aralkyl group, hydroxyl group, thiol group, amino group which may have a substituent, preferably an alkoxy group having 1 to 32 carbon atoms, preferably an aryloxy group having 6 to 18 carbon atoms, 32 alkylthio groups,
Preferably an arylthio group having 6 to 18 carbon atoms, preferably an acylamino group having 2 to 32 carbon atoms, preferably an alkoxycarbonyl group having 2 to 32 carbon atoms, preferably a sulfonylamino group having 1 to 32 carbon atoms, preferably 6 ~
18 aryl groups, preferably a carbamoyl group having 1 to 32 carbon atoms, preferably a ureido group having 1 to 32 carbon atoms, preferably a urethane group having 2 to 18 carbon atoms, a sulfamoyl group which may have a substituent, preferably Is an acyl group having 2 to 32 carbon atoms, preferably an acyloxy group having 2 to 32 carbon atoms, preferably an alkoxycarbonyl group having 2 to 32 carbon atoms, a cyano group, a carboxy group, a sulfo group, and preferably having 1 to 32 carbon atoms. Sulfonyl group, preferably having 3 to 3 carbon atoms
32 represents a heterocyclic group, and R1 to R4 may be linked to form a ring (for example, formation of a saturated ring by a trimethylene group, tetramethylene group, etc., formation of a naphthalene ring by benzolog). Further, these substituents may be further substituted by another substituent. R1 to R4
May be the same or different. R1 to R4
Preferred examples include a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a substituted amino group and the like.

R5 and R6 may have a substituent, and are preferably an aryl group having 6 to 32 carbon atoms (eg, phenyl, 4-methoxyphenyl, 4-trifluoromethylphenyl, 4-phenylsulfonylphenyl) , 2-
Methoxy-4-diethylaminophenyl group, 4-diethylaminophenyl group, 3,5-dichlorophenyl group, etc.), which may have a substituent, preferably having 2 to 32 carbon atoms.
Alkenyl group (for example, 2-phenylethenyl group, 2
-(4-diethylaminophenyl) ethenyl group, 2-
(4-trifluoromethylphenyl) ethenyl group, 2-
(2,4-dimethoxyphenyl) ethenyl group, etc.), and optionally substituted arylcarbonyl group (eg, benzoyl group, 4-propoxybenzoyl group, 4-diethylaminobenzoyl group, 3,5-dichlorobenzoyl group, etc.) , Which may have a substituent, preferably having 3 to 32 carbon atoms.
(E.g., a 2-pyridyl group, a 4-pyridyl group, a 2-furyl group, a 2-thiophenyl group, a 2-thiazolyl group, a 2-benzthiazolyl group, and the like). Also, R5
And R6 may be the same or different from each other. When these have a substituent, the substituent is preferably a substituent which may be substituted by halogen, an alkyl group having 1 to 18 carbon atoms, more preferably a dialkylamino group having 1 to 18 carbon atoms of alkyl (for example, A diethylamino group), and more preferably an arylsulfonyl group having 6 to 32 carbon atoms.

X represents -O-, -S-, -NR7-, and R7 represents an alkyl group or an aryl group which may have a substituent and preferably has 1 to 32 carbon atoms.

In the above general formula (2), R8 to R
11 is an aryl group having 6 to 32 carbon atoms which may have a substituent (for example, phenyl group, 4-methoxyphenyl group, 4-
Trifluoromethylphenyl group, 2-methoxy-4-diethylaminophenyl group, 4-diethylamino group, 3,
5-dichlorophenyl group, 4-cyanophenyl group, 3-
A nitrophenyl group or the like, which may have a substituent, preferably a heterocyclic group having 3 to 32 carbon atoms (for example, a 2-pyridyl group, a 4-pyridyl group, a 2-furyl group, a 2-thiophenyl group, R8 to R11 may be the same or different from each other. R8 to R
11 may be linked to form a ring, particularly a condensed copolycyclic ring (eg, a Phencyclones derivative, an Acecyclones derivative, etc.), or an alkyloxycarbonyl group having preferably 2 to 18 carbon atoms (eg, a methoxycarbonyl group, an ethoxycarbonyl group). The substituent is preferably a dialkylamino group of alkyl having 1 to 18 carbon atoms (eg, diethylamino group, dibutylamino group), an alkoxy group (eg, butoxy group), an alkylthio group. (Eg, butylthio group), halogen atom, cyano group, nitro group and the like are preferable.

It is desirable to adjust the absorption wavelength of these dyes by introducing a substituent, or to control the reaction rate by changing the energy level of HOMO or LUMO.

Hereinafter, specific examples of the decolorizable dye useful in the present invention will be shown, but the present invention is not limited thereto.

Specific Examples of Decolorable Dye

[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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[0030]

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It is desirable to confirm by a model test system that the decolorizable dye used in the present invention is decolorized by a cycloaddition reaction. For example, in a test tube, a dye, a decoloring agent, a suitable high boiling point solvent (alkyl phthalate, phosphate, citrate, benzoate, alkylamide, fatty acid ester, trimesate,
(Polyalcohols, etc.) and heating at 100 to 200 ° C. for several minutes. Alternatively, a pigment or decolorant is dissolved in a suitable solvent (water, a water-soluble organic solvent, a low-boiling or high-boiling organic solvent) and dispersed in a suitable binder (gelatin, polyvinyl alcohol, polyvinyl butyral, etc.), It can be confirmed by heating a sample coated and dried on a transparent support at 100 to 200 ° C. for several minutes. The decolorizable dye used in the present invention is 0.1 to
It is preferable to use in the range of 100 mmol / m ² ,
More preferably, it is used in the range of 5 to 10 mmol / m ² .

Various decolorizing agents usable in the present invention include:
"Dienes in the Diels-Alder reaction", John Wiley
& Sons, Inc., 1990, "Hetero Diels-Alder met
hodology in organic synthesis '', Academic Press, IN
C., 1987, "Tetrahedron organic chemistry se
ries ", vol8, PERGAMON PRESS, 1990," 1,4-Cycl
oaddition reactions ", Academic Press, INC., 196
All chemical species generally known in organic chemistry, such as those described in 7 years, can be used.

For example, there may be mentioned cycloaddition-reactive monomers, oligomers and polymers thereof. Cycloaddition-reactive monomers include C—C unsaturated bonds, C
Compounds having at least one -N unsaturated bond, CS unsaturated bond, NN unsaturated bond, and N-O unsaturated bond can be used. Examples of these are acrylic acid and its salts, acrylic esters, acrylamides, methacrylic acid and its salts, methacrylic esters, methacrylamides, vinyl alkyl ketones, acrylonitriles, maleic anhydride, maleic esters , Fumaric acid esters, acetylene carboxylic acid esters, benzoquinones, 1,4-naphthoquinones, N-substituted maleimides, N-substituted-1,2,4-triazoline-3,
5-diones, itaconic esters, styrenes, vinyl ethers, vinyl esters, N-vinyl heterocycles and the like. These may be monomers or oligomers or polymers having a degree of polymerization of 10,000 or less as long as these monomer units are polymerized at the terminals.

Although all of these compounds are useful in the present invention, in the present invention, those which hardly diverge during heating and have a boiling point of 80 ° C. or more are preferred because they are subjected to heat development. Hereinafter, specific examples of the decoloring agent particularly useful in the present invention will be described.
The present invention is not limited to this.

Specific Examples of Decoloring Agent

[0036]

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[0037]

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[0038]

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[0039]

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[0040]

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The decoloring agent used in the present invention is preferably used in the range of 50 to 1000 mol%, more preferably 100 to 500 mol%, based on the dye.

The decoloring agent is preferably applied in the form of microcapsules.

When forming two sheets of recording material,
What is necessary is just to apply | coat and apply the layer containing the microcapsule in which the decoloring agent was included, and the decolorable pigment | dye to separate sheets respectively.

When a mono-sheet recording material is formed, a decolorizable dye is added to a layer different from the layer containing microcapsules containing a decolorant from the viewpoint of raw storage stability and discrimination. It is preferred to add. It is more preferable to provide an intermediate layer between the layer containing the microcapsules containing the decoloring agent and the layer containing the decolorable dye.

The microcapsules preferably used in the present invention have a heat-responsive property capable of strictly shielding the substance in the capsule at normal temperature, and at the same time, increasing the permeability of the wall at the time of heating, thereby releasing the inclusions. Microcapsules are preferred.

As the wall material of the capsule, gelatin, polyurea, polyurethane, polyimide, polyester, polycarbonate, melamine resin, urea resin and the like can be used. From the viewpoint of obtaining a thermoresponsive microcapsule, polyurea and / or polyurethane can be used. It is preferred to use

The glass transition temperature of the capsule wall can be controlled by selecting one kind of polymer of the capsule wall or adding an appropriate plasticizer. Examples of such a plasticizer include a phenol compound, an alcohol compound, an amide compound, and a sulfonamide compound. These may be contained in a capsule or may be added as a dispersion to the outside of a microcapsule.

Regarding the technique of microencapsulation, specific examples of materials and compounds used, see, for example, US Pat.
No. 726804 and No. 3796696.

The average particle size of the microcapsules is 0.0
It is preferably from 5 to 25 μm, more preferably from 0.1 to 3 μm. The addition amount of the wall material is generally 5 to 500% by weight, preferably 10 to 100% by weight of the included substance.

In the production of microcapsules preferably used in the present invention, when an oily liquid containing a compound containing an ethylenically unsaturated bond is dispersed in an aqueous medium, the aqueous medium contains a water-soluble polymer. Is preferred. In this case, the amount of the oily liquid containing the polymerizable decolorizing agent is preferably 10 to 120% by weight based on the aqueous medium, and 20 to 9% by weight.
0% by weight is more preferred.

Examples of the water-soluble polymer include various kinds of gelatin, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, polymethyl vinyl ether, polyacryloyl morpholine, polyhydroxyethyl acrylate, polyhydroxyethyl methacrylate-coacrylamide, hydroxyethyl cellulose, and hydroxypropyl cell. Ross and methyl cellulose, polystyrene sulfinic acid, copolymer of styrene sulfinic acid, polystyrene sulfonate, copolymer of styrene sulfonic acid, polyvinyl sulfate, polyvinyl sulfonate, maleic anhydride / styrene copolymer, maleic anhydride Acids, isobutylene copolymers and the like can be mentioned.

In the present invention, various accelerators can be used to accelerate the decoloring reaction of the dye. As the accelerator, a compound generally known in organic chemistry that promotes a cycloaddition reaction can be used. An example is a Lewis acid catalyst. Specifically, generally known AlCl ₃ , TiCl ₄ , SnCl ₄ , Z
In addition to nCl ₂ etc., Mg (NTf ₂ ) ₂ , ZN (NTf ₂ ) ₂ , La (N) described in Chemistry Letters, 307 (1995)
Tf ₂ ) ₃ · H ₂ O, La (NTfSO ₂ C ₄ F ₉ ) ₃
・ 2H ₂ O, La (NTfSO ₂ C ₈ F ₁₇ ) ₃・ 1.5
H ₂ O, etc., Journal of the Society of Synthetic Organic Chemistry, 53, p370
(1995), Yb (OTf) ₃ , JACS, 5
464 (1992) [Ti (Cp) ₂ (H ₂ O) ₂ ] ²⁺
(TfO) ₂ ^2- (Cp = 1,2,3,4,5-pentamethylcyclopenta-1,3-diene) or the like, or Nafio
Acid resins such as nH are preferably used. These accelerators can be used alone or in combination of several kinds, and may be introduced into any layer of the light-sensitive material. Further, the addition amount of these catalysts can be used in a wide range. Useful ranges are from 1 mol% to 300 mol%, more preferably from 10 mol% to 100 mol%, based on the dye.

The silver halide emulsifier which can be used in the present invention may be any of silver chloride, silver bromide and silver iodide, or silver chlorobromide, silver chloroiodide, silver iodobromide and silver chloroiodobromide. good. The halogen composition in the grains may be uniform. Multiple structures having different compositions on the surface and inside may be used (JP-A-57-154232, JP-A-58-108533, JP-A-59-48755, JP-A-59-52237, U.S. Pat. No. 4,433,048 and EP100984). . Also,
The thickness of the particles is not more than 0.5 μm,
tabular grains having an average aspect ratio of 5 or more (US Pat. Nos. 4,414,310 and 4,435,499;
S3241646A1) or a monodisperse emulsion having a nearly uniform particle size distribution (JP-A-57-178235, JP-A-58-100846, JP-A-58-14829, WO8)
3 / 02338A1, EP64412A3, and 83377A1) can also be used in the present invention. 2 different in habit, halogen composition, grain size, grain size distribution, etc.
More than one kind of silver halide may be used in combination. The gradation can also be adjusted by mixing two or more kinds of monodispersed emulsions having different grain sizes.

The average grain size of the silver halide used in the present invention is preferably from 0.001 μm to 10 μm, more preferably from 0.01 μm to 5 μm. These silver halide emulsions may be prepared by any of an acidic method, a neutral method, and an ammonia method. The reaction between the soluble silver salt and the soluble halide may be a one-sided mixing method, a simultaneous mixing method. Alternatively, any of these combinations may be used. Back-mixing method in which particles are formed in excess of silver ions, or a controlled method for keeping pAg constant
The double jet method can also be adopted. Further, in order to accelerate the grain growth, the addition concentration, the amount or the addition speed of the silver salt and the halogen salt to be added may be increased (Japanese Patent Application Laid-Open No. 55-7955).
Nos. 142329 and 55-158124; U.S. Pat.
No. 650575).

Epitaxial silver halide emulsions can also be used (JP-A-56-16124, US Pat. No. 409).
No. 4684).

In the present invention, when silver halide is used alone without using an organic silver salt oxidizing agent, it is preferable to use silver chloroiodide or iodobromide which can recognize the X-ray pattern of silver iodide crystals. It is silver and silver chloroiodide. For example, when a nitric acid solution is added to a potassium bromide solution to produce silver bromide particles, and then potassium iodide is added, silver iodobromide having the above characteristics can be obtained.

In the step of forming silver halide grains used in the present invention, ammonia may be used as a silver halide solvent, including an organic thioether derivative described in JP-B-47-11386 or an organic thioether derivative described in JP-A-53-144319. A sulfur compound or the like can be used. Cadmium salts, zinc salts, lead salts, thallium salts, and the like may be allowed to coexist in the process of particle formation or physical ripening.

Further, for the purpose of improving high light failure and low light failure, water-soluble iridium salts such as iridium chloride (III), (IV), ammonium hexachloroiridate, etc.
Alternatively, a water-soluble rhodium salt such as rhodium chloride can be used.

The soluble salts may be removed from the silver halide emulsion after the formation of the precipitate or after the physical ripening. Therefore, the silver halide emulsion can be subjected to the Nudel washing method or the sedimentation method. The silver halide emulsion may be used as it is immature, but is usually used after chemical sensitization. A known chalcogen sensitization method, reduction sensitization method, noble metal sensitization method, or the like can be used alone or in combination with an emulsion for a normal photosensitive material. These chemical sensitization methods can also be carried out in the presence of a nitrogen-containing heterocyclic compound (Japanese Patent Application Laid-Open No. 58-1983).
-126526 and 58-215644).

The silver halide emulsion of the present invention may be a surface latent image type in which a latent image is mainly formed on the surface of a grain, or an internal latent image type in which a latent image is formed inside a grain. When an internal latent image type emulsion is used, it is preferable to use a direct reversal emulsion in combination with a nucleating agent. Internal latent image type emulsions suitable for this purpose are described in U.S. Pat. Nos. 2,592,250 and 3,761,276.
No., JP-B-57-136641, and the like.
Preferred nucleating agents for combination are described in US Pat.
No. 7552, No. 4245037, No. 4255511
No. 4266013, No. 4276364 and O
It is described in LS2635316.

The coating amount of the photosensitive silver halide used in the present invention is preferably 1 mg / m ² to 50 g / m ² in terms of silver. More preferably, it is in the range of 50 mg / m ² to 10 g / m ² .

In the present invention, an organic silver salt which is relatively stable to light can be used in combination with the photosensitive silver halide as an oxidizing agent. In this case, it is necessary that the photosensitive silver halide and the organic silver salt are in a contact state or in a close distance. When heated to a temperature of 80 ° C., preferably 100 ° C. or higher, it is considered that the organometallic oxidizing agent participates in redox using the latent image of silver halide as a catalyst.

Examples of the organic compound that can be used to form such an organic silver salt oxidizing agent include aliphatic or aromatic carboxylic acids, compounds containing a mercapto group or a thiocarbonyl group having an α-hydrogen, and imino groups. Contained compounds and the like.

The silver salts of the aliphatic carboxylic acids include behenic acid, stearic acid, oleic acid, lauric acid, capric acid, myristic acid, palmitic acid, maleic acid, fumaric acid, tartaric acid, fruic acid, linoleic acid and linolenic acid. ,
Silver salts derived from adipic, sebacic, succinic, acetic, butyric or camphoric acid are typical examples.
Silver salts derived from aliphatic carboxylic acids having a halogen atom or a hydroxyl group-substituted product or a thioether group of these fatty acids can also be used.

Silver salts of aromatic carboxylic acids and other compounds containing a carboxyl group include benzoic acid, 3,5-
Dihydroxybenzoic acid, o-, m- or p-methylbenzoic acid, 2,4-dichlorobenzoic acid, acetamidobenzoic acid, p-phenylbenzoic acid, gallic acid, tannic acid, phthalic acid, terephthalic acid, salicylic acid, phenylacetic acid , Pyromellitic acid or 3-carboxymethyl-4-
A typical example is a silver salt derived from methyl-4-thiazoline-2-thione.

Examples of silver salts of compounds having a mercapto or thiocarbonyl group include 3-mercapto-4-phenyl-1,2,4-triazole, 2-mercaptobenzimidazole, 2-mercapto-5-aminothiadiazole, Dithiocarboxylic acids such as mercaptobenzthiazole, S-alkylthioglycolic acid (alkyl groups having 12 to 22 carbon atoms), dithioacetic acid; thioamides such as thiostearoamide; 5-carboxy-1-methyl-2-phenyl-4-thiopyridine, mercapto Triazine, 2-mercaptobenzoxazole, mercaptooxadiazole or 3-amino-5-benzylthio-1,2,4
And silver salts derived from mercapto compounds described in U.S. Pat. No. 4,123,274.

The silver salt of the compound having an imino group includes
Benzotriazole or derivatives thereof described in JP-B-44-30270 or JP-B-5-18416, for example, alkyl-substituted benzotriazoles such as benzotriazole and methylbenzotriazole; halogen-substituted benzotriazoles such as 5-chlorobenzotriazole; Carboimidobenzotriazoles such as imidobenzotriazole; nitrobenzotriazoles described in JP-A-58-118639;
No. 38, such as sulfobenzotriazole, carboxybenzotriazole or a salt thereof, or hydroxybenzotriazole; and from 1,2,4-triazole, 1H-tetrazole, carbazole, saccharin, imidazole and derivatives thereof described in U.S. Pat. No. 4,220,709. Derived silver salts are mentioned as typical examples.

Also, RD17029 (June 1978)
Organic salts other than silver salts and silver salts such as copper stearate described in JP-A-60-113235, and silver salts of carboxylic acids having an alkynyl group such as phenylpropiolic acid described in JP-A-60-113235 can also be used in the present invention.

The above organic silver salt is 1 m of photosensitive silver halide.
It is preferably 0.01 to 500 mol, more preferably 0.3 to 30 mol, per ol. The total coating amount of the photosensitive silver halide and the organic silver salt is preferably 0.05 to 20 g / m ² , more preferably 0.1 to 10 g / m ² , in terms of silver.

The silver halide used in the present invention may be spectrally sensitized with dyes. The dyes used include methine dyes, cyanine dyes, merocyanine dyes,
Complex cyanine dyes, complex merocyanine dyes, polopolar cyanine dyes, hemicyanine dyes, styryl dyes and hemioxonol dyes are included. Particularly useful dyes are those belonging to the cyanine dyes, merocyanine dyes, and complex merocyanine dyes. For these dyes, any of the nuclei usually used for cyanine dyes as basic heterocyclic nuclei can be used. That is, a pyrroline nucleus, an oxazoline nucleus, a thiazoline nucleus, a pyrrole nucleus, an oxazole nucleus, a thiazole nucleus, a selenazole nucleus, an imidazole nucleus, a tetrazole nucleus, a pyridine nucleus, and the like; a nucleus in which an alicyclic hydrocarbon ring is fused to these nuclei; Nucleus fused with an aromatic hydrocarbon ring, i.e., indolenine nucleus, benzoindolenine nucleus, indole nucleus, benzoxazole nucleus, naphthoxazole nucleus, benzothiazole nucleus, naphthothiazole nucleus, benzoselenazole nucleus, benzimidazole A nucleus, a quinoline nucleus and the like can be applied. These nuclei may be substituted on carbon atoms. The merocyanine dye or composite merocyanine dye includes, as nuclei having a ketomethylene structure, pyrazolin-5-one nucleus, thiohidatoin nucleus, 2-thiooxazoline-2,4-dione nucleus, thiazolidine-2,4-dione nucleus, rhodanine nucleus, thione A 5- to 6-membered heterocyclic nucleus such as a barbituric acid nucleus can be applied.

These sensitizing dyes may be used alone or in combination, and the combination of sensitizing dyes is often used particularly for supersensitization. Along with the sensitizing dye, the emulsion may contain a dye which does not itself have a spectral sensitizing effect or a substance which does not substantially absorb visible light and exhibits supersensitization. For example, aminosyltyl compounds substituted with a nitrogen-containing heterocyclic group (for example, those described in US Pat. Nos. 2,933,390 and 3,635,721), and aromatic organic acid formaldehyde condensates (for example, those described in US Pat. No. 3,743,510) , Cadmium salts, azaindene compounds and the like. U.S. Pat. Nos. 3,615,613, 3,615,641 and 3,
The combinations described in 617295 and 3635721 are particularly useful.

In the photothermographic material of the present invention, a reducing agent can be used, and those which are usually used in the field of photothermographic materials can be used.

Examples of the reducing agent usable in the present invention include, for example, US Pat. Nos. 3,531,286 and 3,7612.
Nos. 70, 3764328, 3342599 and 3719492, and Research Disclosure No. 12146, No. 15108, No. 15127
And JP-A-56-27132 and JP-A-53-13562.
No. 8, No. 57-79035, p-phenylenediamine-based and p-aminophenol-based developing agents, phosphoramidophenol-based, sulfonamidoaniline-based developing agents, and hydrazone-based color developing agents,
Use of phenols, sulfonamidophenols, or polyhydroxybenzenes, naphthols, hydroxybinaphthols, methylenebisnitols, methylenebisphenols, ascorbic acid, 3-pyrazolidones, pyrazolones, hydrazines, hydrazides, and the like. Can be.

Particularly preferred reducing agents include hindered phenols, methylene bisphenols, hydrazides, sulfonamide phenols and the like. Two or more reducing agents may be used simultaneously.

The amount of the reducing agent used in the photothermographic material of the present invention depends on the type of the photosensitive silver halide used,
Although it is not always constant depending on the type of the organic acid silver salt and the type of the other additives, it is usually preferably 0.01 mol to 1500 m per 1 mol of the photosensitive silver halide.
ol, more preferably 0.1 mol to 200 mol
It is.

In the present invention, various accelerators can be used to accelerate the reaction between the silver salt and the reducing agent. Accelerators include compounds that make the reaction system basic and promote development, including bases or base precursors.

Various bases or base precursors are known. The base precursor mentioned here releases a base component by heating, and a three-dimensionally bulky organic base is preferable.

Examples of preferred bases include aliphatic amines (trialkylamines, hydroxyalkylamines, aliphatic polyamines), aromatic amines (N-alkyl-substituted aromatic amines, N-hydroxyalkyl-substituted) Aromatic amines and bis [p- (dialkylamino)
Phenyl] methanes), heterocyclic amines, polysubstituted amidines, cyclic amidines, polysubstituted guanidines, cyclic guanidines, polysubstituted bisguanidines, and pK
Those having a of 8 or more are preferable, and those having a pKa of 10 or more are more preferable.

When a base is contained in the light-sensitive material, it is preferably added in the form of a precursor. Examples of the base precursor include salts of an organic acid and a base which decompose and decompose by heating, compounds which decompose to release amines by reactions such as intramolecular nucleophilic substitution reaction, Rossen rearrangement, Beckmann rearrangement, etc. Those which cause a reaction to release a base are preferably used. Preferred base precursors include salts of trichloroacetic acid described in British Patent No. 998949, salts of α-sulfonylacetic acid described in US Pat. No. 4,060,420, salts of propiolic acids described in JP-A-59-180537, and US Pat. Patent No. 40884
No. 96 2-carboxycarboxamide derivative,
Examples thereof include hydroxam carbamates described in JP-A-59-168440 utilizing the Rossen rearrangement, and aldoxime carbamates described in JP-A-59-157637 which generates a nitrile by heating. In addition, British Patent No. 998945, U.S. Pat. No. 3,220,846,
JP-A-50-22625, British Patent No. 2079480
The base precursors described in (1) are also useful. These bases can be used alone or in combination of several kinds.

The base or base precursor can be added in a wide range. The useful range is 50 wt.
%, More preferably 0.01 wt% to 40 wt%.

In the present invention, the decolorizable dye and the decolorant can be introduced into the image recording material by various methods. For example, a solution dissolved in water or a hydrophilic organic solvent can be directly provided on a support together with a binder, if necessary. Further, it can be introduced into a layer of a photosensitive material by a known method such as the method described in U.S. Pat. No. 2,322,027. In that case, a high-boiling organic solvent or a low-boiling organic solvent as described below can be used.

For example, alkyl phthalate (eg, dibutyl phthalate, dioctyl phthalate), phosphate (eg, diphenyl phosphate, triphenyl phosphate), citrate (eg, tributyl acetyl citrate), and benzoate (eg, octyl benzoate) , Alkylamides (eg, diethyl laurylamide), fatty acid esters (eg, dibutoxyethyl succinate, dioctyl azelate), trimesic acid esters (eg, tributyl trimesate) and the like; or a boiling point of about 30 to 1000 ° C. Organic solvents such as ethyl acetate, lower alkyl acetates such as butyl acetate, ethyl propionate, secondary butyl alcohol,
After dissolving in methyl isobutyl ketone, β-ethoxyethyl acetate methyl cellosolov acetate, cyclohexanone, etc., it is dispersed in a hydrophilic colloid. The above-mentioned high-boiling organic solvent and low-boiling organic solvent may be mixed and used.

Further, a dispersion method using a polymer described in JP-B-51-39853 and JP-A-51-59943 can also be used. When dispersed in hydrophilic colloid,
Various surfactants can be used.

The binder used in the present invention can be contained alone or in combination. As the binder, a hydrophilic one can be mainly used. Representative examples of the hydrophilic binder include transparent or translucent hydrophilic binders, such as gelatin, gelatin derivatives, proteins such as cellulose derivatives, starch, natural products such as polysaccharides such as gum arabic, and polyvinyl. It includes synthetic polymer substances such as water-soluble polyvinyl compounds such as alcohol, modified polyvinyl alcohol, polyvinylpyrrolidone, and acrylamide polymer. Other synthetic polymeric materials include vinyl compounds on dispersion which increase the dimensional stability of the photographic material, especially in the form of a latex.

The support used for the photosensitive material in the present invention can withstand the processing temperature. As a general support, not only glass, paper, metal and its analogs are used, but also acetylcellulose film, cellulose ester film, polyvinyl acetal film, polystyrene film, polycarbonate film, polyethylene terephthalate film and related materials. Film or resin material is included. Also, a paper support laminated with a polymer such as polyethylene can be used. The polyesters described in U.S. Pat. Nos. 3,640,089 and 3,725,070 are preferably used.

The photothermographic material of the present invention may optionally contain a protective layer, an anti-curl layer, a fluorescent whitening agent, a fading inhibitor, a pigment,
It may contain a water release agent, a thermal polymerization inhibitor, a surfactant, a thermal solvent and the like.

The decolorizable dye of the present invention may be added to any layer of the light-sensitive material. That is, any layer of the photosensitive material may be a colored layer in the present invention. For example, the coloring composition of the present invention may be added to the layer under the emulsion layer or the backside of the support for the purpose of preventing halation, or may be added to the silver halide emulsion layer for the purpose of preventing irradiation. Alternatively, a filter dye may be added to an intermediate layer (for example, an intermediate layer sandwiched between different color-sensitive emulsion layers or an intermediate layer sandwiched between substantially the same color-sensitive emulsion layers) or a protective layer.

The photothermographic material according to the present invention can take various forms depending on the silver halide emulsion, the decolorizable dye, the method of introducing the decolorant, the layer structure at the time of coating, and the like. It is.

When a mono-sheet recording material is formed, it is necessary to introduce a decolorizable dye and a decolorant in a separated form from the viewpoint of raw storage stability. As a method of separation, for example, a decolorizable dye and a decolorant are added to separate layers in a multilayer structure. In this case, it is preferable to provide an intermediate layer. Alternatively, it is also possible to disperse the decolorizable dye and / or the decolorant in a solid state and incorporate them in the same layer or another layer so that they do not react until heat treatment.

When two sheets of the photothermographic material are formed, the decolorizable dye may be incorporated in the sheet containing the silver halide emulsion and the decolorant may be incorporated in the other sheet. Can be performed using any of the introduction methods described above.

For the photothermographic material of the present invention, various means can be used as an imagewise exposure method. For example, as an exposure light source, a tungsten lamp, a halogen lamp, a xenon lamp, a mercury lamp, a cathode ray tube flying spot, a light emitting diode, a laser (for example, a gas laser, a YAG laser, a dye laser, a semiconductor laser, etc.), a CRT light source, a FOT, etc. Various types can be used alone or in combination. A semiconductor laser and a second harmonic generation element (SHG element) can also be used. In addition, exposure may be performed using light emitted from a phosphor excited by an electron beam, X-ray, γ-ray, α-ray, or the like. The exposure time is usually 1/1000 second to 1 second, which is usually used in cameras, and is 1/10
Exposure shorter than 00 seconds, for example, exposure using a xenon flashlight or a cathode ray tube, can also be used. If necessary, the spectral composition of light used for exposure can be adjusted by a color filter.
The photosensitive material of the present invention can be used for scanner exposure using a laser or the like.

The photothermographic material of the present invention includes a step of subjecting the photothermographic material to thermal development simultaneously with or after imagewise exposure and heating to decolor the colored layer. The colored layer of the photothermographic material of the present invention can be decolored in the case of a mono-sheet system at the time of heat development or by a reheating treatment thereafter. In the case of a two-sheet system, the photosensitive sheet can be decolorized by exposing and thermally developing the sheets, superimposing the sheets containing the decoloring agent, and performing heat treatment again.

The heating means is described in JP-A-61-29
As in the case of the photosensitive material described in Japanese Patent No. 4434, a heating element layer may be provided on the surface of the support on which the photosensitive layer of the photosensitive material is not coated, and heating may be performed. Further, as described in JP-A-61-147244, a hot plate, an iron, and a heat roller are used, or as described in JP-A-62-144166, a photosensitive material is sandwiched between a heat roller and a belt for heating. A method may be used.

That is, the photosensitive material may be brought into contact with a heating element having a surface area greater than the area of the photosensitive material, and the entire surface may be heated simultaneously. In addition to the heating method of directly contacting the heating element and the photosensitive material as described above, electromagnetic waves, infrared rays,
Hot air or the like can be applied to the photosensitive material to heat it in a non-contact state.

In the heat development and decoloring by heating, it is preferable that heating is performed after 0.1 seconds or more have passed after image exposure. The heating temperature is generally between 60 ° C and 250 ° C, preferably 8 ° C.
0 ° C. to 150 ° C. and the heating time is between 0.1 second and 5 minutes.

[0096]

EXAMPLES The method for producing the light-sensitive material of the present invention will be specifically described below with reference to experimental examples and examples, but the present invention is not limited thereto.

Example 1 <Preparation of microcapsules (cp-1)> In a 100 cc stainless steel cup for a homogenizer, 21.6 g of the monomers shown in Table 1 were dissolved in 10.56 g of ethyl acetate. Takenate D-110N (manufactured by Takeda Pharmaceutical) 5.
76 g was added and the mixture was stirred at room temperature for 10 minutes to prepare an oily solution. To this solution, 30 g of a 10% aqueous solution of PVA-217E (manufactured by Kuraray) was added, and the mixture was stirred at 10,000 rpm for 5 minutes using a cutter blade. Further, add 15 cc of water, stir at 10,000 rpm for 10 seconds, and
An emulsion in the form of an emulsion was obtained. This emulsion was stirred for 5 minutes at 1200 rpm with a propeller blade.
The temperature was raised to 0 ° C., and the mixture was further stirred for 60 minutes. After cooling to room temperature, 25 cc of water was added and stirred,
A microcapsule dispersion liquid (cp-1) having a polyurea resin as a capsule wall was prepared.

<Preparation of Antihalation Layer> 6.6 g of polyvinyl butyral having an average molecular weight of 5,000 was dissolved in a mixed solution of 31 g of toluene and 121 g of methyl ethyl ketone to obtain a polymer solution. Decolorable dye 3.1 shown in Table 1
mmol was dissolved in 24.5 g of the polymer solution to prepare a coating solution.

The above coating solution was applied on a heat-treated 100 μm-thick polyethylene terephthalate film so as to have a wet application amount of 21 cc / m ² and dried at room temperature.

Further, 12 g of a 10% aqueous solution of PVA-405 (manufactured by Kuraray), 20.6 cc of water, 12 g of the microcapsules (cp-1) and a surfactant (WW-
0.8 cc of a 5% aqueous solution of 1) is added in sequence, and
The coating solution stirred for 1 minute was applied so as to have a wet application amount of 21 cc / m ^2, and dried at 45 ° C. to prepare materials 1 to 10.

The above-prepared materials 1 to 10 were heat-treated at 100 ° C., 115 ° C., and 130 ° C. for 20 seconds using a heat drum.

<Evaluation of Decolorability in Heat Treatment> The blue light density and green light density of the heat-treated material were measured using a Macbeth densitometer. With respect to the evaluation of the color erasing property, the color erasing rate (%) by the heat treatment was obtained by comparing with the concentration before the heat treatment using the following formula.

(Decolorization rate by heat treatment) = 100− (concentration after heat treatment) × 100 / (concentration before heat treatment) The results obtained are shown in Table 1.

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[0105]

[Table 1]

Table 1 shows that the material of the present invention loses its color at 115 ° C. or higher. In addition, it was confirmed that equivalent results could be obtained with various combinations of the above-described exemplary decolorizable dyes and decolorants.

Example 2 <Preparation of silver halide grains A> 7.5 g of inert gelatin and 10 mg of potassium bromide were dissolved in 900 ml of water, the temperature was adjusted to 35 ° C. and the pH was adjusted to 3.0, and 74 g of silver nitrate was added. An aqueous solution containing 370 ml of an aqueous solution containing potassium bromide and potassium iodide in a molar ratio of (96/4) was added over 10 minutes by a control double jet method while maintaining the pAg at 7.7. At this time, hexacyanoferrate (III) and hexachloroiridium (III) are added simultaneously with the start of silver nitrate addition.
The complex salt was added at 1 × 10 ⁻⁵ mol / Ag mol. Then 4
-Hydroxy-6-methyl 1,3,3a, 7-tetrazaindene (0.3 g) was added and the pH was adjusted to 5 with sodium hydroxide.
Thus, cubic silver iodobromide grains having an average grain size of 0.06 μm, a variation coefficient of the projected diameter area of 8%, and a [100] face ratio of 87% were obtained. This emulsion was subjected to coagulation sedimentation using a gelatin coagulant, and after desalting, 0.1 g of phenoxyethanol was added to adjust the pH to 5.9 and the pAg to 7.5.

<Preparation of Organic Acid Silver Emulsion A> 10.6 g of behenic acid was put in 300 ml of water, dissolved by heating at 90 ° C., and sufficiently stirred, 31.1 ml of 1N sodium hydroxide was added. Was left for 1 hour. Then 3
After cooling to 0 ° C., 7.0 ml of 1N phosphoric acid was added and, with sufficient stirring, 0.13 g of N-bromosuccinimide was added. Thereafter, the silver halide grains A prepared in advance were added while stirring at 40 ° C. so that the silver amount was 10 mol% with respect to behenic acid. Further, 25 ml of a 1N aqueous solution of silver nitrate was continuously added over 2 minutes, and the mixture was left for 1 hour with stirring.

While stirring the aqueous mixture, 37 g of a 1.2 wt% solution of polyvinyl acetate in n-butyl acetate was gradually added to form a floc of the dispersion, and water was removed. Was removed, 20 g of a mixed solution of polyvinyl butyral (average molecular weight 3000) of 2.5 wt% butyl acetate and isopropyl alcohol 1: 2 was added with stirring, and the thus obtained gel-like silver behenate and To the mixture of silver halides, 12.5 g of polyvinyl butyral (average molecular weight: 4000) and 57 g of isopropyl alcohol were added and dispersed to obtain an organic fatty acid silver emulsion A.

On the opposite side of the material 8 prepared in Example 1, the following photosensitive layer and surface protective layer were sequentially applied.

<Coating on Photosensitive Layer Surface Side> Photosensitive layer: A solution having the following composition was applied to the opposite side of the back layer so that the coated silver amount was 1.5 g / m ² to form a photosensitive layer. Organic fatty acid silver salt emulsion A 73 g Sensitizing dye D-1 (0.05% methanol solution) 4 ml Phthalazine (5% methanol solution) 2.5 ml Hydrazine derivative H-1 (1% methanol solution) 2 ml Antifoggant-1 (1.7% DMF solution) 2.5 ml Developer-1 (10% acetone solution) 13 ml 2-mercapto-5-methylbenzotriazole (0.5% DMF solution) 5 ml CaBr ₂ (0.3% methanol solution) 6.5 ml

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Surface protective layer: A liquid having the following composition was wetted to a thickness of 1
It was applied on the photosensitive layer so as to have a thickness of 00 μm. Acetone 175 ml methanol 15 ml cellulose acetate 8.0 g 4-methylphthalic acid 0.72 g tetrachlorophthalic acid 0.22 g tetrachlorophthalic anhydride 0.5 g The photothermographic material was prepared as described above.

The heat-developable photosensitive material was subjected to thermal development at 100 ° C., 115 ° C., and 130 ° C. using a heat drum without exposing the photosensitive material, and the dye of the antihalation layer was decolored at each temperature. I asked for time.

30 seconds at 100 ° C. and 15 seconds at 115 ° C.
At 130 ° C. for 10 seconds.

As described above, it can be seen that the present invention can provide an antihalation layer capable of decoloring even at a temperature of about 100 ° C.

Example 3 <Preparation of antihalation layer> 6.6 g of polyvinyl butyral having an average molecular weight of 5,000 was dissolved in a mixed solution of 31 g of toluene and 121 g of methyl ethyl ketone to obtain a polymer solution. A coating solution was prepared by dissolving 3.1 mmol of the exemplary decolorizable dye D-33 in 24.5 g of the above polymer solution.

The above coating solution was applied onto a heat-treated 100 μm-thick polyethylene terephthalate film at a wet application amount of 21 cc / m 2 and dried at room temperature. <Preparation of photothermographic material>

On the other side of the above film, the photosensitive layer of Example 2 and the surface protective layer were sequentially applied in the same manner as in Example 2, to prepare a photothermographic material. <Preparation of Decolorizing Agent Sheet> 12 g of a 10% aqueous solution of PVA-405 (manufactured by Kuraray), 20.5 cc of water, 12 g of the microcapsules (CP-1) prepared in Example 1 and a surfactant (WW-1) 0.8 cc of a 5% aqueous solution is sequentially added,
For 15 minutes to prepare a coating solution. This coating solution was applied on a heat-treated polyethylene terephthalate film having a thickness of 75 μm so as to have a wet application amount of 21 cc / m 2, and dried at 45 ° C. to prepare a decolorizing agent sheet.

Using a heat drum without exposing the photothermographic material, the decolorizing agent sheet was brought into close contact with the side of the photothermographic material having the antihalation layer, and
Thermal development was performed at 115C and 130C.

In the same manner as in Example 2, the time required for the color of the dye of the antihalation layer to disappear at each temperature was determined.

The results were the same as those in Example 2. Thus, it can be seen that the present invention is effective even in the case of two sheets in which the dye and the decoloring agent are separated, and that an antihalation layer capable of decoloring even at a temperature of about 100 ° C. can be provided.

[0124]

As described above, according to the present invention, it is possible to provide a photothermographic material having a colored layer which is stable with time and excellent in decoloration during heat treatment, and provides a photothermographic material having high sharpness. Thus, a photothermographic material having a small thickness and a small amount of added material can be provided.

Claims (3)

[Claims] 1. A photothermographic material having a colored layer which is decolorized by heat treatment, wherein the colored layer contains at least a dye which is decolorized by a cyclization addition reaction, and the dye is subjected to a cyclization addition reaction on the support. A photothermographic material having a decoloring agent for causing decoloration by causing the color. 2. A photothermographic material comprising a support having thereon a colored layer which is decolorized by heat treatment, wherein the colored layer contains at least a dye which is decolorized by a cycloaddition reaction, and is provided on a support different from the support. A photothermographic material having a decoloring agent for causing a cycloaddition reaction with at least a dye on a body to decolor the body. 3. A photothermographic material having a colored layer decolorizable by heat treatment on a support, wherein the support comprises at least a photosensitive silver halide and a color containing a dye decolorable by a cycloaddition reaction. A photothermographic material comprising a layer and a decoloring agent which causes a cycloaddition reaction with the dye to decolor.