JP2001022027A - Heat developable photographic sensitive material, x-ray image forming unit and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a heat developable photographic sensitive material applicable to a medical X-ray photographing photosensitive material, having high sensitivity and high sharpness and free from color residue after processing by disposing a layer containing an organic silver salt, photosensitive silver halide and a reducing agent for silver ions on each of both sides of a substrate comprising polyethylene naphthalate. SOLUTION: The heat developable photographic sensitive material has a layer containing an organic silver salt, photosensitive silver halide and a reducing agent for silver ions on each of both sides of the substrate comprising polyethylene naphthalate. The photosensitive silver halide has been chemically sensitized with a chalcogen compound. The reducing agent may be contained in a layer other than the photosensitive silver halide-containing layer. The heat developable photographic sensitive material preferably contains at least one compound of the formula, wherein W1-W4 each H or a monovalent substituent but at least one of W1-W4 is the monovalent substituent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photothermographic material, an X-ray image forming unit and an image forming method.

[0002]

2. Description of the Related Art Conventionally, in the field of printing plate making and medical treatment, a waste liquid accompanying wet processing of an image forming material has been a problem in terms of workability. There is a strong demand for weight loss.

[0003] Techniques for preventing the processing waste liquid from being discharged include:
A heat-developable photographic light-sensitive material that forms a photographic image by using a heat-development processing method is exemplified. See, for example, US Pat.
No. 2,904, No. 3,457,075, and D.C. Morgan and B.A. "The Silver System Treated by Heat (Therma)" by Shelly
llly Processed Silver System
ems) "(Imaging Processors and
Materials (Imaging Processes)
and Materials) Neblette Eighth Edition, Sturge, V.A. Walworth, A .; Shepp, page 2, 1969.

Such a photothermographic material is prepared by dispersing a reducible silver source (for example, an organic silver salt), a catalytically active amount of a photocatalyst (for example, silver halide), and a reducing agent in a usual (organic) binder matrix. It is contained in a state where it is used. The photothermographic material is stable at room temperature, but generates silver through a redox reaction between a reducible silver source (functioning as an oxidizing agent) and a reducing agent when heated to a high temperature after exposure. This oxidation-reduction reaction is promoted by the catalytic action of the latent image generated by the exposure. The silver formed by the reaction of the organic silver salt in the exposed areas provides a black image, which is in sight with the unexposed areas, and the image is formed.

However, in this method, there is no processing step for dissolving and removing silver halide as in the case of conventional wet-processed light-sensitive materials, and a small silver halide must be used. There is no example applied in fields such as X-ray photography.

Further, such a heat-developable photographic material is referred to as X
When used as a double-sided photosensitive material for radiography, a dye layer is required to block crossover light from one side, and there is no step of removing the dye as in the conventional wet processing in the development processing step. , Making it more difficult to apply.

[0007]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to solve these problems and to provide a high-sensitivity, high-sharpness, heat-developable photographic light-sensitive material which can be applied to medical X-ray photographic materials. It is to provide materials.

[0008]

The above object of the present invention is achieved by the following constitution.

(1) A photothermographic method comprising a layer containing an organic silver salt, a photosensitive silver halide and a reducing agent for silver ions on both sides of a support made of polyethylene naphthalate. material.

(2) The photothermographic material as described in (1) above, wherein the photosensitive silver halide is chemically sensitized with a chalcogen compound.

(3) The photothermographic material as described in (1) or (2) above, wherein the reducing agent is contained in a layer different from the layer containing the photosensitive silver halide.

(4) The above-mentioned item (1), which comprises at least one compound represented by the following general formula (1):
3. The photothermographic material according to claim 1.

[0013]

Embedded image

[Wherein W _{1 to} W ₄ each independently represent a hydrogen atom or a monovalent substituent, and at least one of W _{1 to} W ₄ is a monovalent substituent. (5) In a photothermographic material having a layer containing an organic silver salt, a photosensitive silver halide and a reducing agent for silver ions on both sides of the support, at least one of the layers on the support A photothermographic material comprising at least one dye which is bleached by heat or light in the support or in both.

(6) The organic silver salt comprises a long-chain fatty acid silver, and the ratio of the long-chain fatty acid silver to the fatty acid is 85:15 to 15:15.
6. The photothermographic material according to any one of the above items 1 to 5, wherein the ratio is 100: 0.

(7) 0.5 mol of photosensitive silver halide
7. The photothermographic material according to any one of items 1 to 6, comprising silver iodobromide grains containing 1% or more of iodine.

(8) An X-ray, wherein the photothermographic material according to any one of (1) to (7) is brought into close contact with a phosphor screen of an X-ray intensifying screen having rare earth phosphor particles. Image forming unit.

(9) The X-ray intensifying screen is 200 n
9. The X-ray image forming unit according to the item 8, wherein the emission spectrum by X-rays is maximum in the range of m to 500 nm.

(10) An image recording method characterized in that an image is obtained by irradiating the X-ray image forming unit according to (8) or (9) with X-rays using an X-ray generator as a light source.

(11) The heat-developable photographic light-sensitive material, on which an image has been recorded by the image recording method described in the above item 10, is used in an amount of 100 to 150
An image forming method characterized in that an image is obtained by heating to ° C.

Hereinafter, the present invention will be described in detail. First, polyethylene naphthalate as a support used in the photothermographic material of the present invention will be described.

The term "polyethylene naphthalate" as used in the present invention is a polyethylene-2,6-naphthalate which is a polymer whose constituent units are substantially composed of ethylene-2,6-naphthalate units. For example, 10 mol% or less, preferably 5 mol% or less of the third
Also included are ethylene-2,6-naphthalate polymers modified by the component.

Polyethylene-2,6-naphthalate is
In general, it is prepared by condensing naphthalene-2,6-dicarboxylic acid or a functional derivative thereof, for example, methyl naphthalene-2,6-dicarboxylate and ethylene glycol under appropriate reaction conditions in the presence of a catalyst. . In that case, as the third component, for example, adipic acid, oxalic acid, isophthalic acid, terephthalic acid, naphthalene-2,
Dicarboxylic acids such as 7-dicarboxylic acid and diphenyl ether dicarboxylic acid or lower alkyl esters thereof, p
Dicarboxylic acids such as oxybenzoic acid and p-ethoxybenzoic acid, or lower alkyl esters thereof, or dihydric alcohols such as propylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, diethylene glycol, and polyethylene; And polyalkylene glycols such as glycol and polytetramethylene glycol.

In the polymerization, a lubricant such as titanium dioxide,
Stabilizers such as phosphoric acid, phosphorous acid and ester salts thereof, antioxidants such as hindered phenol, polymerization regulators, plasticizers and the like may be added.

The polyethylene naphthalate used in the present invention has a limiting viscosity of 0.4 or more, preferably 0.55 to 5, since the mechanical stability is reduced if the degree of polymerization is too low.
0.9 is preferred. It is not preferable that the crystallinity is too low for dimensional stability.
5% or more and 60% or less are preferable.

The use of the polyethylene-2,6-naphthalate film of the present invention is such that if the dust adheres to the film during use, the commercial value of the film is reduced, so that the surface specific resistance value is 10 ^14.
It is preferably Ω · cm or less. As a method of obtaining such a film, a method of applying an antistatic agent, a method of forming a thin layer of a metal or a metal compound on the film surface, a method of adding an antistatic agent during polymerization of polyester raw material, and a method of forming a film It is appropriately used such as a method of mixing a polyester raw material and an antistatic agent. Among them, polyethylene-2,6-naphthalene obtained by performing polycondensation in the presence of sodium alkylbenzenesulfonate and polyalkylene glycol as raw materials may be used.

The polyethylene-2,6 used in the present invention
-Naphthalene refers to a monomer in which 40 mol% or more of the monomer to be polymerized is dimethyl naphthalene-2,6-dicarboxylate, preferably 60 mol% or more, more preferably 80 mol% or more.

The surface of these supports may be provided with an undercoat layer, or subjected to corona discharge, ultraviolet irradiation, etc. in order to improve the adhesion of the coating layer.

In the present invention, the silver halide grains function as an optical sensor. In a heat development system, the average grain size is preferably smaller in order to suppress white turbidity after image formation and to obtain good image quality. Are preferable, and the average particle size is 0.1 μm or less, more preferably 0.01 μm or less.
μm to 0.1 μm, particularly preferably 0.02 μm to 0.08 μm. The term "grain size" as used herein refers to the length of a ridge of a silver halide grain when the silver halide grain is a cubic or octahedral so-called normal crystal. In the case of non-normal crystals, for example, in the case of spherical, rod-shaped or tabular grains, it refers to the diameter of a sphere equivalent to the volume of silver halide grains. Further, the silver halide is preferably monodispersed. Here, the monodispersion means that the degree of monodispersion determined by the following formula is 40% or less. More preferably 30%
Or less, particularly preferably 0.1% or more and 20% or less.

Monodispersity = (standard deviation of particle size) / (average value of particle size) × 100 The shape of silver halide grains is not particularly limited, but the proportion occupied by the Miller index [100] plane is high. It is preferable that this ratio is 50% or more, further 70% or more,
In particular, it is preferably at least 80%. Miller index [1
The ratio of the [00] plane is determined by utilizing the dependence of the adsorption of the photosensitive dye on the [111] plane and the [100] plane. Tan
i. Imaging Sci. , 29, 165 (1
985).

Another preferred form of silver halide is tabular grains. The term “tabular grain” as used herein means that the thickness in the vertical direction is h when the square root of the projected area is the particle size r μm.
The aspect ratio = r / h in the case of μm is 3 or more. Among them, the aspect ratio is preferably 3 or more and 5 or more.
0 or less. The particle size is preferably 0.1 μm or less, and more preferably 0.01 μm to 0.08 μm. These are disclosed in U.S. Pat.
Nos. 314,798 and 5,320,958, and the like, and the desired tabular grains can be easily obtained. When these tabular grains are used in the present invention,
Further, the sharpness of the image is improved. The halogen composition is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide, and silver iodide. However, the photosensitive silver halide of the present invention preferably comprises silver iodobromide grains containing 0.5 mol% or more of iodine, more preferably 0.7 mol% to 5 mol%. If the iodine content is lower than this range, it is difficult to obtain the required sensitivity, and if the iodine content is high, the developability deteriorates and the gradation becomes soft, which is not preferable.

The photographic emulsion used in the present invention is described in US Pat. Gl
afkids Chimieet Physique
e Photographique (Paul Mon
tel, 1967); F. By Duffin
Photographic Emulsion Chem
istry (published by The Focal Press, 19
66); L. By Zelikman et al
Making and Coating Photog
raphic Emulsion (TheFocal
Press, 1964) and the like. That is, any of an acidic method, a neutral method, an ammonia method, and the like may be used, and a method of reacting a soluble silver salt with a soluble halide may be any of a one-sided mixing method, a simultaneous mixing method, a combination thereof, and the like. Good. The silver halide may be added to the image forming layer by any method, in which case the silver halide is arranged close to the reducible silver source. Further, the silver halide may be prepared by converting a part or all of the silver in the organic acid silver by the reaction of the organic acid silver and the halogen ion into silver halide, or may be prepared by preparing silver halide in advance. In advance, this may be added to a solution for preparing an organic silver salt, or a combination of these methods is possible, but the latter is preferred. Generally, silver halide is 0.75 to organic silver salt.
Preferably, it is contained in an amount of 30% by weight.

The silver halide used in the present invention preferably contains ions of a transition metal belonging to Group 6 to Group 10 of the Periodic Table of the Elements in order to improve illuminance failure and adjust the improvement. As the above metals, W, Fe, Co, Ni,
Cu, Ru, Rh, Pd, Re, Os, Ir, Pt, A
u is preferred, and these metal ions may be introduced into silver halide in the form of a metal complex or complex ion, although a metal salt may be directly introduced into silver halide. As the transition metal complex and the metal complex ion, a hexacoordinate complex ion represented by the following general formula is preferable.

In the formula [ML ₆ ] ^m , M is a transition metal selected from the elements of Groups 6 to 10 of the periodic table, L is a bridging ligand, and m is 0, 1-, 2-, or 3-.
Or 4-. Specific examples of the ligand represented by L include halides (fluoride, chloride, bromide and iodide), cyanide, cyanate, thiocyanate, selenocyanate, tellurocyanate, azide and aquo. Ligand, nitrosyl, thionitrosyl and the like, preferably aquo, nitrosyl and thionitrosyl. If an aquo ligand is present, it preferably occupies one or two of the ligands. L may be the same or different.

Particularly preferred examples of M are rhodium (Rh), ruthenium (Ru), rhenium (Re), iridium (Ir) and osmium (Os).

The following are specific examples of the transition metal coordination complex ion.

[0037] 1: [RhCl _6] ^3- 2: [RuCl _6] ^3- 3: [ReCl _6] ^3- 4: [RuBr _6] ^3- 5: [OsCl _6] ^3- 6: [IrCl _6] ^{4 -} 7: [Ru (NO) Cl _5] ^2- 8: [RuBr ₄ (H ₂ O)] ^2- 9: _{[Ru (NO) (H 2 O} ) Cl 4 ] ^- 10: [RhCl ₅ (H ₂ O)] ^2- 11: [Re (NO) Cl _5] ^2- 12: [Re (NO) CN _5] ^2- 13: [Re (NO) ClCN _4] ^2- 14: [Rh (NO) ₂ Cl _4] ^- 15: _{[Rh (NO) (H 2 O} ) Cl 4 ] ^- 16: [Ru (NO) CN _5] ^2- 17: [Fe (CN) _6] ^3- 18: [Rh (NS) Cl _5] ^2- 19: [Os (NO) Cl _5] ^2- 20: [Cr (NO) Cl _5] ^2- 21: [Re (NO) Cl _5] ^- 22: [Os (NS) Cl ₄ (TeCN )] ^2- 23: Ru (NS) Cl _5] ^2- 24: _{[Re (NS) Cl 4 (SeCN} ) ] ^2- 25: [Os (NS) Cl (SCN) 4 ] ^2- 26: [Ir (NO) Cl _5] ^{2 -} 27: [Ir (NS) Cl _5] ^2- 28: [IrCl _6] ^2- these metal complexes or complex ions may be one type,
Two or more metals of the same type and different types of metals may be used in combination.

The content of these metal ions, metal complexes and complex ions is generally from 1 × 10 ^-9 to 1 × 10 ^-2 mol per mol of silver halide, preferably from 1 × 10 ^-9 to 1 × 10 ^-2 mol. X 10 ^-8 to 1 X 10 ^-4 mol. Compounds that provide these metal ions or complex ions are preferably added during silver halide grain formation and incorporated into silver halide grains, and preparation of silver halide grains,
That is, it may be added at any stage before and after nucleation, growth, physical ripening, and chemical sensitization, but it is particularly preferable to add at the stage of nucleation, growth, and physical ripening. It is preferably added at the stage of nucleation. In the addition, the compound may be added in several divided portions, may be uniformly contained in the silver halide grains, or may be added uniformly to the silver halide grains, as described in JP-A-63-29603, JP-A-2-306236, and JP-A-2-306236. No. 167545, 4-
No. 76534, No. 6-110146, No. 5-2736
As described in JP-A-83, etc., the particles can be contained in the particles with a distribution. These metal compounds may be water or a suitable organic solvent (eg, alcohols, ethers, glycols, ketones, esters, amides).
, For example, an aqueous solution of a powder of a metal compound or a metal compound and NaCl, KCl
A method in which an aqueous solution obtained by dissolving the silver halide solution and the silver salt solution is added to a water-soluble silver salt solution or a water-soluble halide solution during grain formation, or added as a third aqueous solution when the silver salt solution and the halide solution are simultaneously mixed. A method of preparing silver halide grains by a three-liquid simultaneous mixing method, a method of charging a required amount of an aqueous solution of a metal compound into a reaction vessel during grain formation, or a method of preparing metal ions or complex ions in advance when preparing silver halide. A method of adding another silver halide grain doped with and dissolving it. In particular, a method of adding an aqueous solution of a powder of a metal compound or an aqueous solution in which a metal compound and NaCl and KCl are dissolved together is added to a water-soluble halide solution. When adding to the particle surface, a required amount of an aqueous solution of a metal compound can be charged into the reaction vessel immediately after the formation of the particles, during or at the end of physical ripening, or at the time of chemical ripening.

The photosensitive silver halide grains can be desalted by washing with a method known in the art such as a noodle method or a flocculation method. Good.

In the present invention, the sensitization by a chalcogen compound is carried out by preparing a silver halide separately, sensitizing the same as in a normal silver halide photograph, and mixing and contacting with an organic silver salt. And a method of mixing these silver halides at the time of preparing an organic silver salt, and both methods can be applied. After the organic silver salt is prepared, a part of these may be converted to silver halide by conversion by adding a halogen source and then sensitized. However, the former method is preferred because high sensitivity can be obtained.

For the sensitization with a chalcogen compound, the method used in the preparation of a conventional silver halide light-sensitive material can be advantageously applied. For example, as a step of preparing silver halide, generally, these compounds are added to a silver halide emulsion, and a process called ripening for holding the silver halide emulsion under appropriate conditions for a certain period of time is performed. be able to.

The chemical sensitization method using a chalcogen compound in the present invention is preferably a sulfur sensitization method, a selenium sensitization method, or a tellurium sensitization method.

As the sulfur sensitizer that can be used in the present invention, various sulfur compounds such as thiosulfates, thioureas, thiazoles, rhodanines and the like can be used in addition to the sulfur compounds contained in gelatin. Can be. Specific examples are described in U.S. Pat. Nos. 1,574,944 and 2,278,9.
No. 47, 2,410,689, 2,728,66
No. 8, 3,501, 313, 3,656,955
It is described in the issue.

As the selenium sensitizer that can be used in the present invention, a selenium compound disclosed in a conventionally known patent can be used. That is, the emulsion is usually used by adding an unstable selenium compound and / or a non-unstable selenium compound and stirring the emulsion at a high temperature, preferably at 40 ° C. or higher for a certain period of time. Examples of unstable selenium compounds include JP-B-41-15748 and JP-B-43-134.
No. 89, JP-A-4-25832, JP-A-4-109240
It is preferable to use the compounds described in the above.

Specific examples of unstable selenium sensitizers include isoselenocyanates (for example, aliphatic isoselenocyanates such as allyl isoselenocyanate), selenoureas, selenoketones, selenoamides, and selenocarboxylic acids (for example, , 2-selenopropionic acid, 2-selenium butyric acid), selenoesters, diacyl selenides (eg, bis (3-chloro-2,6-dimethoxybenzoyl) selenide), selenophosphates, phosphine selenides, colloidal metals And selenium.

Although the preferred types of unstable selenium compounds have been described above, they are not intended to be limiting. Those skilled in the art will note that an unstable selenium compound as a sensitizer for a photographic emulsion is not very important as long as selenium is unstable, and the structure of the selenium sensitizer molecule is not important. It is generally understood that the moieties carry selenium and have no role other than to make them present in the emulsion in an unstable manner. In the present invention, an unstable selenium compound having such a broad concept is advantageously used.

Non-labile selenium compounds used in the present invention include JP-B-46-4553 and JP-B-52-3449.
Compounds described in Nos. 2 and 52-34491 are used. Non-labile selenium compounds include, for example, selenous acid, potassium selenocyanide, selenazoles, quaternary salts of selenazoles, diaryl selenides, diaryl diselenides, dialkyl selenides, dialkyl diselenides, 2-selenazolidinediones, 2-selenooxazolidinethione and derivatives thereof.

The tellurium sensitizers used in the present invention include, for example, JP-A-4-204640 and JP-A-4-271.
No. 341, 4-33343, 5-303157
Nos. 6-27573, 6-175258, 6
-180478, 6-208184, 6-20
Nos. 8146, 6-317867 and 7-92599
Nos. 7-98483, 7-104415, 7
No. 140579, and Journal of Chemical Society Chemical Communication (J.
Chem. Soc. Chem. Commun. ) 635
(1980); Patai (S. Patai), The
Chemistry of Organic Selenium and Tellurium Compounds (The Chemis)
try of Organic Selenium T
ellurium compounds), Vol. 1
(1986), Vol. 2 (1987) can be used.

Specific compounds include (Te-a) diacyl tellurides, bis (oxycarbonyl) tellurides, bis (carbamoyl) tellurides (specifically, for example, dibenzoyl telluride, bis (2,6 -Dimethoxybenzoyl) telluride, bis (ethoxycarbonyl) telluride, bis (N-methyl-N-phenylcarbamoyl) telluride, bis (N-benzyl-N-phenylcarbamoyl) telluride, and the like; and diacyl ditellurides. , Bis (oxycarbonyl) ditellurides,
Bis (carbamoyl) ditellurides (specifically, for example, dibenzoylditelluride, bis (N-methyl-N-
Phenylcarbamoyl) ditelluride, bis (N, N-diphenylcarbamoyl) ditelluride and the like. ),
(Te-b) Compounds having a P = Te bond (for example, phosphine tellurides (for example, tributylphosphine telluride, tri-iso-butylphosphine telluride, tri-iso-propylphosphine telluride, n-butyldi-iso) -Propylphosphine telluride), tellurophosphonic acid amides (e.g., tris (dimethylamino) phosphane telluride, tris (diethylamino) phosphane telluride, etc.), tellurophosphinic acid esters (e.g., diethyl telluro) Phosphinic acid-O-ethyl ester (Et ₂ (E
tO) P = Te)), tellurophosphonic acid esters (e.g., ethyldiethoxyphosphane telluride), (Te-c) tellurocarboxylates (e.g., tellurobenzoic acid potassium salt, 2-methoxytel) Lobenzoic acid potassium salt),
(Te-d) Te-organyl tellurocarboxylates (eg, Te- (3'-oxobutyl) tellurobenzoate, Te-methyltellurobenzoate, etc.),
(Te-e) di (poly) tellurides, tellurides (eg, diethyl ditelluride, bis (cyanoethyl) ditelluride, dipyridyl ditelluride, etc.), (Te-f) tellurols (eg, ethanetellurol, (Te-g) telluroacetals (e.g., 1,1-bis (methyltelluro) butane, tritellurane, etc.), (Te-h) tellurosulfonates (e.g., Te-ethylbenzenetellurosulfonate) ), (Te-i) a compound having a P-Te bond (for example, tellurophosphoric acid), Te-organyl ester (for example, specifically, tellurophosphoric acid-O, O-diethyl-Te) -Methyl ester,
Tellurophosphoric acid-O, O-dibutyl-Te
-Ethyl ester), (Te-j) -containing Te heterocycles (eg, tellaradiazoles and the like), (Te-k)
Tellurocarbonyl compounds (e.g., telluroureas (e.g., N, N'-dimethylethylene
Cyclic tellurourea compounds such as N'-diethylethylene tellurorea are preferred. ), Telluroamides (eg, dimethyltellurobenzamide, N, N-dipropyl-4-)
Methoxytellurobenzamide, etc.), tellurohydrazides (eg, (N, N ', N'-trimethyl) tellurobenzohydrazide, etc.), (Te-1) inorganic tellurium compounds (eg, tellurium sulfides, sodium telluride, potassium telluride) , Etc.), (Te-m) colloidal tellurium, and the like.

In the present invention, chemical sensitization by sulfur sensitization and / or selenium sensitization and / or tellurium sensitization is preferably performed.
Alternatively, at least chemical sensitization by tellurium sensitization is preferably performed. Further, in the present invention, sulfur sensitization, selenium sensitization, and tellurium sensitization may be used alone or in any combination, however, as a preferred embodiment, any two or three types are used. Combinations are included.

The amount of the chalcogen sensitizer used in the present invention is not particularly limited as long as the effects of the present invention are exhibited, but is not less than 1 × 10 ^-8 mol per mol of silver halide.
× 10 ^-1 mol or less, more preferably ¹ × 10 ^-1 mol
^-7 mol or more and 1 × 10 ^-2 mol or less.

The addition of the chalcogen sensitizer in the present invention is not particularly limited as long as the effects of the present invention are exhibited. Preferably, after forming the silver halide grains, the organic fatty acid silver (to be described later) and the silver halide grains are added. Is more preferable, and more preferably, after desalting silver halide grains and before mixing with organic fatty acid silver.

The silver halide emulsion of the present invention can be used by adding a noble metal sensitization method such as a gold compound, platinum, palladium or iridium compound or a reduction sensitization method to the above-described sensitization method using a chalcogen compound. . As the compound preferably used in these sensitization methods, known compounds can be used, and the compounds described in JP-A-7-128768 can be used. Compounds preferably used in the noble metal sensitization method include, for example, chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, gold selenide, and US Pat. No. 2,448,06.
No. 0, British Patent 618,061 and the like can be preferably used. As specific compounds of the reduction sensitization method, in addition to ascorbic acid and thiourea dioxide, for example, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds and the like can be used. . Further, reduction sensitization can be achieved by ripening the emulsion while maintaining the pH of the emulsion at 7 or more or the pAg at 8.3 or less.
Further, reduction sensitization can be achieved by introducing a single addition portion of silver ions during grain formation.

The silver halide emulsion of the present invention is preferably spectrally sensitized with a spectral sensitizing dye.

The spectral sensitizing dye is adsorbed on silver halide grains and contributes to sensitization. In the present invention, when the sensitizing dye is adsorbed on silver halide emulsion grains and the reflection spectrum is measured, the maximum absorption wavelength of the J aggregation band is 55%.
It is preferably 5 nm or less. In the application to X-ray medical light-sensitive materials utilizing a phosphor emitting green light, the spectral sensitizing dye according to the present invention is adsorbed on silver halide emulsion grains, and the fluorescence is measured when its reflection spectrum is measured. Preferably, the J-band is formed in the same wavelength range as the green light from the body. That is, it is preferable to select and combine spectral sensitizing dyes such that a J-band having a maximum absorption is preferably formed in the region of 520 nm to 555 nm. More preferably 53
0-553 nm, most preferably 540-550 nm
It is.

These spectral sensitizing dyes may be used in combination with other spectral sensitizing dyes. Dyes used include cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, holopolar cyanine dyes, hemicyanine dyes, styryl dyes, and hemioxonol dyes. Particularly useful dyes are those belonging to the cyanine dyes, merocyanine dyes and complex merocyanine dyes. These dyes can be applied to any of the nuclei commonly 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 nucleus such as a nucleus in which an alicyclic hydrocarbon ring is fused to these nuclei, Indolenine nucleus, benzindolenin nucleus, indole nucleus, naphthoxazole nucleus, benzothiazole nucleus, naphthothiazole nucleus, benzoselenazole nucleus, benzimidazole nucleus, quinoline nucleus and the like can be applied. These nuclei may be substituted on carbon atoms.

The merocyanine dye or the complex merocyanine dye has pyrazoline- as a nucleus having a ketomethine structure.
A 5- to 6-membered heterocyclic nucleus such as a 5-one nucleus, a thiohydantoin nucleus, a 2-thiooxazolidine-2,4-dione nucleus, a thiazoline-2,4-dione nucleus, a rhodanine nucleus, and a thiobarbituric acid nucleus is applied. can do.

These dyes are described in German Patent No. 929,0.
No. 80, U.S. Pat. Nos. 2,231,658 and 2,4
No. 93,748, No. 2,503,776, No. 2,
No. 519,001, No. 2,912,329, No. 3,655,394, No. 3,656,959, No. 3,672,897, No. 3,649,217,
British Patent No. 1,242,588, JP-B-44-140
No. 30, etc.

These sensitizing dyes may be used alone or in combination, and a 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 exposure of the photothermographic material of the present invention, an Ar laser (488 n
m), a He-Ne laser (633 nm), a red semiconductor laser (670 nm), and an infrared semiconductor laser (780
nm, 820 nm), and the like. When used for medical X-ray photography, it is preferable to irradiate a unit consisting of a fluorescent intensifying screen and a photosensitive material with X-rays for exposure.

The addition amount of the spectral sensitizing dye in the present invention is
Type of dye and structure, composition, ripening condition of silver halide,
Depending on the purpose and application, the coverage of the monomolecular layer on the surface of each photosensitive particle in the silver halide emulsion is 30% or more and 90% or more.
%, Preferably 40% to 8%.
0% is particularly preferred.

The appropriate addition amount of the spectral sensitizing dye per mole of silver halide varies depending on the total surface area of silver halide grains dispersed in the emulsion, but is preferably less than 600 mg.
Further, it is preferably 450 mg or less.

As a solvent for the sensitizing dye, a conventionally used water-miscible organic solvent can be used. Specific examples thereof include alcohols, ketones, nitriles, and alkoxy alcohols. Examples include propyl alcohol, isopropyl alcohol, ethylene glycol, propylene glycol, 1,3-propanediol, acetone, acetonitrile, 2-methoxyethanol, and 2-ethoxyethanol.

A surfactant has conventionally been used as a dispersant for the spectral sensitizing dye. Surfactants include anionic, cationic, nonionic and amphoteric surfactants, and any of these surfactants can be used in the present invention.

The sensitizing dye may be added after the silver halide is formed and before the organic silver salt is formed, or after the organic silver salt is dispersed,
It may be at any time during the preparation of the photosensitive layer coating solution.

These sensitizing dyes may be used alone or in combination, and the combination of sensitizing dyes is often used particularly for supersensitization. A dye that does not itself have a spectral sensitizing effect or a substance that does not substantially absorb visible light, together with a sensitizing dye,
A substance exhibiting supersensitization may be contained in the emulsion.

In the present invention, the organic silver salt is a reducible silver source, and a silver salt of an organic acid or a hetero organic acid containing a reducible silver ion source, particularly a long chain (10 to 30, preferably 15 to 25, And the nitrogen-containing heterocycle is preferred. Organic or inorganic silver salt complexes wherein the ligand has a total stability constant for silver ions of 4.0 to 10.0 are also useful. Examples of suitable silver salts are Research
h Disclosure Nos. 17029 and 29963
And salts thereof: organic acid salts (eg, salts of gallic acid, oxalic acid, behenic acid, stearic acid, arachidic acid, palmitic acid, lauric acid, etc.); carboxyalkylthiourea salts of silver (Eg, 1- (3-carboxypropyl) thiourea, 1- (3-carboxypropyl) -3,3-dimethylthiourea, etc.); a silver complex of a polymer reaction product of an aldehyde and a hydroxy-substituted aromatic carboxylic acid ( For example, aldehydes (formaldehyde, acetaldehyde, butyraldehyde, etc.), hydroxy-substituted acids (eg, salicylic acid, benzoic acid, 3,5
-Dihydroxybenzoic acid, 5,5-thiodisalicylic acid), silver salts or complexes of thiones (eg, 3- (2-carboxyethyl) -4-hydroxymethyl-4- (thiazoline-2-thione, and 3- Carboxymethyl-4-
Thiazoline-2-thione)), imidazole, pyrazole, urazole, 1,2,4-thiazole and 1H-tetrazole, 3-amino-5-benzylthio-1,2,2
Complexes or salts of silver and a nitrogen acid selected from 4-triazole and benzotriazole; silver salts such as saccharin and 5-chlorosalicylaldoxime; and silver salts of mercaptides. Preferred silver sources are silver behenate, silver arachidate,
It is silver stearate. The organic silver salt is preferably contained at a silver amount of 4 g / m ² or less. More preferably 3 g
/ M ² or less.

The organic silver salt compound can be obtained by mixing a water-soluble silver compound and a compound which forms a complex with silver, and can be obtained by a forward mixing method, a reverse mixing method, a simultaneous mixing method, and a method described in JP-A-9-12764.
A controlled double jet method as described in No. 3 is preferably used.

The long-chain fatty acid silver preferably used in the present invention has a ratio of fatty acid silver to fatty acid of 85:15 to 100: 0.
And more preferably 87:13 to 9
5: 5. Below this ratio, when trying to coat the silver amount of fatty acid silver to obtain the required concentration, Dmin
The transparency of the portion deteriorates, and if it is higher than that, the fog density increases, which is not preferable. This ratio is determined by the amount of silver in 100 g of long chain fatty acid silver powder by X-ray crystal diffraction,
It is calculated as the silverization rate from the raw material fatty acid. It is preferable to add a toning agent to the photothermographic material of the present invention. Examples of suitable toning agents are Research Disc
No. 17029, which includes the following:

Imides (eg, phthalimide); cyclic imides, pyrazolin-5-ones, and quinazolinones (eg, succinimide, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and 2 , 4-thiazolidinedione); naphthalimides (eg, N-hydroxy-1,8-naphthalimide); cobalt complexes (eg, hexamine trifluoroacetate of cobalt), mercaptans (eg, 3
-Mercapto-1,2,4-triazole); N- (aminomethyl) aryldicarboximides (for example,
N- (dimethylaminomethyl) phthalimide); blocked pyrazoles, isothiuronium (isoth
uronium) derivatives and certain photobleaches (eg, N, N'-hexamethylene (1-carbamoyl-3,5-dimethylpyrazole), 1,8-
A combination of (3,6-dioxaoctane) bis (isothiuronium trifluoroacetate) and 2- (tribromomethylsulfonyl) benzothiazole; a merocyanine dye (e.g., 3-ethyl-5-((3-ethyl -2-benzothiazolinylidene (benzothiazolinylidene))-1-methylethylidene) -2-thio-2,4
Oxazolidinedione); phthalazinone, a phthalazinone derivative or a metal salt of these derivatives (for example, 4-
(1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7-dimethyloxyphthalazinone, and 2,3
-Dihydro-1,4-phthalazinedione); a combination of phthalazinone and a sulfinic acid derivative (for example, 6-chlorophthalazinone + sodium benzenesulfinate or 8-methylphthalazinone + sodium p-trisulfonate); phthalazine + phthalate Acid combinations; phthalazine (including phthalazine adducts) and maleic anhydride,
And phthalic acid, 2,3-naphthalenedicarboxylic acid or o
At least one selected from phenylene acid derivatives and anhydrides thereof (for example, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride);
Quinazolinediones, benzoxazines, naloxazine derivatives; benzoxazine-2,4-diones (eg, 1,3-benzoxazine-2,4-dione); pyrimidines and asymmetric triazines (E.g., 2,4-dihydroxypyrimidine) and tetraazapentalene derivatives (e.g., 3,
6-dimercapto-1,4-diphenyl-1H, 4H-
2,3a, 5,6a-tetraazapentalene). Preferred toning agents are phthalazone or phthalazine.

Further preferred examples of the color tone agent include the compounds represented by the above formula (1).

As the substituent represented by W _{1 to} W ₄ , for example, an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, Methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), alkenyl Group (preferably having 2 to 2 carbon atoms)
20, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, for example, vinyl, allyl, 2-butenyl, 3-pentenyl and the like. ), Alkynyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 2 carbon atoms)
12, particularly preferably 2 to 8, for example, propargyl, 3-pentynyl and the like. ), An aryl group (preferably having 6 to 30 carbon atoms, more preferably having 6 carbon atoms)
-20, particularly preferably 6-12 carbon atoms, for example, phenyl, p-methylphenyl, naphthyl and the like. ), An amino group (preferably 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 0 carbon atoms)
6, for example, amino, methylamino, dimethylamino, diethylamino, dibenzylamino and the like. ), An alkoxy group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 12 carbon atoms, and particularly preferably having 1 carbon atoms.
To 8, for example, methoxy, ethoxy, butoxy and the like. ), An aryloxy group (preferably having 6 to 20 carbon atoms, more preferably having 6 to 16 carbon atoms, particularly preferably having 6 to 12 carbon atoms, for example, phenyloxy,
2-naphthyloxy and the like. ), An acyl group (preferably having 1 to 20 carbon atoms, more preferably having 1 carbon atom)
To 16, particularly preferably 1 to 12 carbon atoms, for example, acetyl, benzoyl, formyl, pivaloyl and the like. ), An alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, more preferably having 2 to 16 carbon atoms, particularly preferably having 2 to 12 carbon atoms, and examples thereof include methoxycarbonyl, ethoxycarbonyl, and cyclohexyloxycarbonyl.) An aryloxycarbonyl group (preferably having 7 to 20 carbon atoms, more preferably having 7 to 16 carbon atoms, particularly preferably having 7 to 10 carbon atoms, such as phenyloxycarbonyl), and an acyloxy group (preferably It has 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, such as acetoxy and benzoyloxy.), An acylamino group (preferably 2 to 2 carbon atoms).
It has 0, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, and includes, for example, acetylamino, benzoylamino and the like. ), An alkoxycarbonylamino group (preferably having 2 to 20 carbon atoms, more preferably having 2 to 16 carbon atoms, particularly preferably having 2 to 12 carbon atoms, and examples thereof include methoxycarbonylamino and the like), aryloxycarbonylamino Group (preferably having 7 to 20 carbon atoms, more preferably having 7 to 16 carbon atoms, particularly preferably having 7 to 12 carbon atoms, such as phenyloxycarbonylamino, etc.), and a sulfonylamino group (preferably having a carbon number of 7). 1 to 20, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, methanesulfonylamino, benzenesulfonylamino and the like.), A sulfamoyl group (preferably 0 to 20 carbon atoms, More preferably 0 to 1 carbon atoms
6, particularly preferably having 0 to 12 carbon atoms, for example, sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, phenylsulfamoyl and the like. ), A carbamoyl group (preferably having 1 to 20 carbon atoms,
More preferably, it has 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include carbamoyl, methylcarbamoyl, ethylcarbamoyl, diethylcarbamoyl, and phenylcarbamoyl. ), An alkylthio group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably having 1 to 12 carbon atoms, such as methylthio and ethylthio, etc.), and an arylthio group (preferably carbon A number 6 to 20, more preferably a carbon number 6 to 16, particularly preferably a carbon number 6 to 12, for example, phenylthio and the like; a sulfonyl group (preferably 1 to 20 carbon atoms, more preferably carbon number) 1 to 16, particularly preferably 1 to 12 carbon atoms, for example, mesyl, tosyl and the like.), Sulfinyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably It has 1 to 12 carbon atoms, for example, methanesulfinyl, benzenesulfinyl, etc.), a ureido group (preferably 1 carbon atom) 20, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, ureide, methylureide, butylureide, phenylureide and the like, a phosphoric amide group (preferably 1 carbon atom) ~
20, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, diethylphosphoric acid amide,
And phenylphosphoramide. ), Hydroxy group, mercapto group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, heterocyclic group (For example, imidazolyl, pyridyl, furyl, piperidyl, morpholino, etc.). These substituents may be further substituted.

As W _{1 to} W ₄ , preferably, a hydrogen atom,
An alkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an acylamino group, a sulfonylamino group, a carbamoyl group, a hydroxy group, a halogen atom, and more preferably a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, An aryloxy group, an acylamino group, a sulfonylamino group, and a halogen atom.

The most preferable group represented by W _{1 to} W ₄ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms,
Preferably, at least one is an alkyl group having 1 to 4 carbon atoms. Further, it is preferable that two or three of the groups represented by W _{1 to} W ₄ represent a hydrogen atom.

W in the compound of the general formula (1) of the present invention
_The monovalent substituent represented by _{1 to} W ₄ may be further substituted, and preferred examples of the substituent are the same as those described above as examples of W _{1 to} W ₄ except for the hydrogen atom. Is mentioned.

Further, two adjacent ones of W _{1 to} W ₄ may be bonded to each other to form a ring, and examples of such a ring include a benzene ring and a 1,3-dioxolen ring.

The following are typical examples of the compound represented by formula (1) of the present invention, but the present invention is not limited thereto.

[0077]

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[0078]

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[0079]

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[0080]

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The compound represented by the general formula (1) of the present invention is described, for example, in R. G. FIG. Elder Field, "He
Trocyclic Compounds ", Joh
n Wiley and Sons, Vol. 1-9,
1950-1967 and A.I. R. Katritzky, "
Comprehensive Heterocyclic
c Chemistry ", Pergamon Pre
ss, 1984 and the like.

Most of the known synthetic methods basically synthesize the corresponding phthalic acid derivatives (phthalaldehyde, phthalic anhydride, phthalic ester, etc.) and condense these with hydrazine to form a phthalazine skeleton. But Tetrahedron Letters, 22,
345 (1981), it is also possible to synthesize from a cyclization reaction of an aryl aldazine derivative.

When W _{1 to} W _{4 have} a nitro group, an amino group, an acylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfonylamino group, a ureido group, a phosphoric amide group, etc., first, nitro-substituted phthalazine Is generally converted to an amino-substituted phthalazine by reduction, and then reacted with various reactants to form the above substituent.

The nitro-substituted phthalazine derivatives include, for example,
A commercially available 3- or 4-nitro-substituted phthalic anhydride is reacted with hydrazine to give a nitro-substituted phthalazinedione (3.
-Or 4-nitro-substituted phthalazinediones are also commercially available), which can be converted to 1,4-dichlorophthalazine and the chlorine atom is removed by a reduction reaction. Further, the phthalazine derivative can be synthesized by directly nitrating it.

When W _{1 to} W _{4 have} a carboxyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group or the like, first, an alkoxycarbonyl-substituted phthalazine is synthesized, and then the ester group is hydrolyzed to a carboxyl group. After the conversion or as it is, the ester group is reacted with various reactants to form the above substituent.

The alkoxycarbonyl-substituted phthalazine derivatives are described, for example, in Heterocycles, 20, 12
79 (1983).

As W _{1 to} W ₄ , a mercapto group, a sulfo group,
In the case of having a sulfino group, a sulfamoyl group, an alkylthio group, an arylthio group, a sulfonyl group, and a sulfinyl group, first, a halogen-substituted phthalazine derivative is synthesized, and a halogen atom is formed of sodium hydrosulfide, or an alkyl mercaptan, or a mercapto group such as an aryl mercaptan, Alternatively, after substitution with an alkylthio group or an arylthio group, the compound is generally reacted with various reactants to form the above substituent.

The halogen-substituted phthalazine derivative can be synthesized by synthesizing phthalazinedione from a halogen-substituted phthalic anhydride and hydrazine, converting it to 1,4-dichlorophthalazine and reducing it in the same manner as in the nitro-substituted phthalazine derivative described above. It is possible.

When W _{1 to} W _{4 have} a hydroxy group, an alkoxy group, an aryloxy group, or an acyloxy group, first, an alkoxy-substituted phthalazine derivative is synthesized, and the O-alkyl group is removed. To form the above substituent.

The alkoxy-substituted phthalazine derivatives are described, for example, in J. Am. Pharm. Sci. , 69, 120 (198
0) or J.I. Org. Chem. , 31, 1912
(1966).

These compounds may be used alone or in combination of two or more.

The compound of the formula (1) of the present invention is preferably contained in an amount of 0.1 to 50% (mol) per mol of silver on the surface having the image forming layer, and 0.5 to 20% ( Mol) is more preferably included.

The compound of the general formula (1) according to the present invention may be a solution,
Any method such as powder and solid fine particle dispersion may be added. Dispersion of solid fine particles can be performed by a known means of micronization (for example,
Ball mill, vibrating ball mill, sand mill, colloid mill, jet mill, roller mill, etc.). When dispersing the solid fine particles, a dispersing aid may be used.
It is preferable that the compound of the general formula (1) of the present invention is added as a solid dispersion.

The addition position of the compound of the general formula (1) of the present invention is not limited, and it is added to the image forming layer (photosensitive layer or heat-sensitive layer), the protective layer and other layers. It is particularly preferable that the layer is the same as or adjacent to the layer containing the organic silver salt, or the same as or adjacent to the layer containing the silver halide.

Binders suitable for the photothermographic material of the present invention are transparent or translucent, generally colorless, and include natural polymer synthetic resins, polymers and copolymers, and other film-forming media such as gelatin, gum arabic, Poly (vinyl alcohol), hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, poly (vinyl pyrrolidone), casein, starch, poly (acrylic acid), poly (methyl methacrylic acid), poly (vinyl chloride), poly (methacrylic acid) ), Copoly (styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinyl acetal) s (eg, poly (vinyl formal) and poly (vinyl butyral)), poly (ester) ) Kind, po (Urethanes), phenoxy resins, poly (vinylidene chloride), poly (epoxides),
Poly (carbonate) s, poly (vinyl acetate),
There are cellulose esters and poly (amides). It may be hydrophilic or non-hydrophilic.

In the present invention, the binder amount of the photosensitive layer is preferably from 1.5 to 6 g / m ² .

More preferably, it is 1.7 to 5 g / m ² . If it is less than 1.5 g / m ² , the density of the unexposed portion will increase significantly and may not be usable.

In the present invention, a matting agent is preferably contained in both the backing layer and the protective layer. In order to improve the dimensional repetition accuracy of the present invention, a polymer matting agent or an inorganic matting agent is added to the entire emulsion layer side. It is preferable to contain 0.5 to 10% by weight to the binder.

The material of the matting agent used in the present invention may be either an organic substance or an inorganic substance. For example, inorganic substances include silica described in Swiss Patent No. 330,158, glass powder described in French Patent No. 1,296,995, etc., and alkali described in British Patent No. 1,173,181 and the like. An earth metal or a carbonate such as cadmium or zinc can be used as a matting agent. As organic matter,
Starch described in U.S. Pat. No. 2,322,037, Belgian Patent 625,451 and British Patent 981,19
No. 8 and the like, and starch derivatives described in JP-B-44-3643.
No. 33, Swiss Patent No. 33
No. 0,158, polystyrene or polymethacrylate; U.S. Pat. No. 3,079,257; polyacrylonitrile; U.S. Pat. No. 3,022,16.
An organic matting agent such as polycarbonate described in No. 9 or the like can be used.

The shape of the matting agent may be either regular or irregular, but is preferably regular and spherical. The size of the matting agent is represented by a diameter when the volume of the matting agent is converted into a sphere. In the present invention, the particle diameter of the matting agent indicates the diameter converted into a sphere.

The matting agent used in the present invention preferably has an average particle size of 0.5 μm to 10 μm, more preferably 1.0 μm to 8.0 μm. The matting agent has a coefficient of variation of the particle size distribution of preferably 50% or less, more preferably 40% or less, and particularly preferably 30% or less.

Here, the coefficient of variation of the particle size distribution is a value represented by the following equation.

(Standard deviation of particle size) / (Average value of particle size) ×
100 The matting agent according to the present invention can be contained in any constituent layer. However, in order to achieve the object of the present invention, the matting agent is preferably a constituent layer other than the photosensitive layer, more preferably from the viewpoint of the support. The outermost layer.

The method of adding the matting agent according to the present invention may be a method of dispersing in a coating solution in advance and applying the solution.
A method of spraying a matting agent after the application liquid is applied and before the drying is completed may be used. When a plurality of types of matting agents are added, both methods may be used in combination.

The photothermographic material of the present invention is stable at room temperature, but is developed by heating to a high temperature after exposure. The heating temperature is preferably from 80 ° C to 200 ° C, more preferably from 100 ° C to 150 ° C. If the heating temperature is 80 ° C. or lower, a sufficient image density cannot be obtained in a short time, and if the heating temperature is 200 ° C. or higher, the binder is melted, and the image itself and the transportability such as transfer to a roller are adversely affected, which is not preferable. Heating generates silver through an oxidation-reduction reaction between an organic silver salt (functioning as an oxidizing agent) and a reducing agent. This oxidation-reduction reaction is accelerated by the catalytic action of the latent image generated on the silver halide upon exposure. The silver formed by the reaction of the organic silver salt in the exposed areas provides a black image, which contrasts with the unexposed areas, resulting in the formation of an image. This reaction process proceeds without supplying a processing liquid such as water from the outside.

The photothermographic material of the present invention has at least one photosensitive layer on both sides of the support. Although only a photosensitive layer may be formed on the support, it is preferable to form at least one non-photosensitive layer on the photosensitive layer. A filter layer may be formed to control the amount or wavelength distribution of light passing through the photosensitive layer, or a dye or pigment may be included in the photosensitive layer. The photosensitive layer may be composed of a plurality of layers, and the sensitivity may be changed to a high-sensitive layer / low-sensitive layer or a low-sensitive layer / high-sensitive layer for adjusting the gradation. Various additives may be added to any of the photosensitive layer, the non-photosensitive layer, and other forming layers. The photothermographic material of the present invention may contain, for example, a surfactant, an antioxidant, a stabilizer, a plasticizer, an ultraviolet absorber, and a coating aid.

In the present invention, a dye which is bleached by heat or light after exposure is contained in the support or in any one of the layers on the support. For the purpose of blocking the crossover light, it is preferable that the compound is contained in a layer closer to the support than the photosensitive layer or in the support.

The dyes used in the crossover light-blocking layer of the present invention include a merocyanine dye that absorbs light transmitted through the photothermographic layer at the time of image exposure to block the crossover light. A method in which the merocyanine dye is decolorized by the action of a halogen radical or hydrohalic acid generated by photodecomposition of the photosensitive halide containing material by overall exposure to make the merocyanine dye transparent (photobleaching) is preferably used.

The photosensitive halogen-containing compound, which is one element of the photobleachable coloring composition preferably used in the crossover light-blocking layer of the present invention, decomposes by irradiation with light to release an organic compound which releases halogen radicals or hydrohalic acid. Compound. Such compounds are described, for example, in US Pat.
No. 2,903, British Patent Nos. 1,432,138, JP-A-50-120328 and JP-A-50-11962.
No. 4, No. 55-24113 and the like, and in the present invention, any of such known photosensitive halogen-containing compounds can be appropriately selected and employed as the photosensitive halogen-containing compound. .

Typical examples of the photosensitive halogen-containing compound of the present invention include compounds represented by the following general formula (I).

[0111]

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In the formula, X represents a halogen atom. R ₁ ,
R ₂ and R ₃ may be the same or different and each represents a hydrogen atom, a halogen atom, a nitro group, an alkyl group having 1 to 10 carbon atoms,
An aryl group having 6 to 14 carbon atoms, an alkylcarbonyl group having 2 to 11 carbon atoms, an arylcarbonyl group having 7 to 15 carbon atoms, an alkyl group having 1 to 10 carbon atoms or 6-1.
Amide group substituted by 4 aryl groups or 1 to 10 carbon atoms
A sulfonate group substituted with an alkyl group or an aryl group having 6 to 14 carbon atoms (the alkyl group or the aryl group in these groups further includes a halogen atom, a hydroxy group, a nitro group, an alkyl group, an aryl group, an alkoxy group, a carbamate Group, a carbonate group, a sulfonate group or a carboxylate group). R
₁ and R ₂ may combine with each other to form a cycloalkyl ring.

More specifically, the compounds included in the general formula (I) include carbon tetrabrombutane, hexabromocyclohexane, α-chloro-p-nitrotoluene, iodoform, hexabromoethane, and benzotrichloride. Α-bromo-p-nitrotoluene, α-bromo-m-nitrotoluene, α, α′-dichloro-o-xylene, α, α′-dibromo-p-xylene, α, α,
Besides α ′, α′-tetrabromoxylene, tribromoethylcinnamate and the like,

[0114]

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Wherein R ₄ represents an alkyl group or an aryl group, and R ₅ represents a hydroxy group, an alkoxy group, a carbamate group, a carbonate group, a sulfonate group, a phosphate group or a carboxylate group;
X represents a halogen atom. For example, 2,2,2-tribromoethanol, 2,2,2-tribromoethylcyclohexanecarbamate, 2,2,2-tribromoethylbenzenecarbamate, 2,2,2-tribromoethylbenzoate, 2,2 2-tribromoethylethyl carbonate, 1,1,1-trichloropropanol,
2,2,2-trichloroethanol, 2,2-dibromo-2-chloro-1-phenylethanol, 2-methyl-
1,1,1-tribromo-2-propanol, bis (2,2,2-tribromoethoxy) diphenylmethane, p-toluenesulfonyltribromoethylurethane, 2,2,2-tribromoethyl stearate, 2,
2,2-tribromoethyl-furoate, bis (2
(2,2-tribromoethyl) succinate and the like:

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Wherein R ₆ represents an amino group, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 14 carbon atoms, and R ₇ represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms. Represents an acyl group having 1 to 10 carbon atoms, and X represents a halogen atom. For example, 2-bromoacetophenone,
2-bromo-2-phenylacetophenone, 2-bromo-1,3-diphenyl-1,3-propanedione, α-
Bromo-2,5-dimethoxyacetophenone, α-bromo-γ-nitro-β-phenylbutyrophenone, α-iodo-γ-nitro-β-phenylbutyrophenone, 2-
Bromo-p-phenylacetophenone, 2-chloro-p
-Phenylacetophenone, 2-bromo-p-bromoacetophenone, 1,3-dichloroacetone, 2,2'-
Formulas such as dichloro-4-chloromethylcarbonamide-benzophenone,

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Wherein R ₈ is a compound having 6 carbon atoms
To 12 aryl groups or benzothiazole groups;
₉ and R ₁₀ may be the same or different, each represents a hydrogen atom, a halogen atom, an alkyl group or an amide group having 1 to 11 carbon atoms having 1 to 5 carbon atoms, X represents a halogen atom. For example, 2-bromo-2-phenylsulfonylacetamide, 2-bromo-2- (p-tolylsulfonyl)
Acetamide, 2-tribromomethylsulfonylbenzothiazole, dibromomethylsulfonylbenzene, tribromomethylsulfonylbenzene, etc., and the formula:

[0120]

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Wherein n and m are 1 to
And R ₁₁ and R ₁₂ are OH

[0122]

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Or --SO ₂ --R ', wherein R' represents an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 12 carbon atoms, and X represents a halogen atom. For example, 2-bromo-
2-nitro-1,3-propanediol, 1,3-dibenzoyloxy-2-bromo-2-nitropropane, 2
-Bromo-2-nitrotrimethylenebis-phenyl carbonate.

Another example is a compound represented by the following general formula (II).

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In the formula, A represents a heterocyclic ring which may have a substituent, and B ₁ , B ₂ and B ₃ each represent an atom selected from a hydrogen atom, a chlorine atom and a bromine atom. However, B ₁ ,
At least one of B ₂ and B ₃ is a chlorine atom or a bromine atom.

As specific examples, ω, ω, ω-tribromoquinaldine, ω, ω-dibromoquinaldine, 2-ω,
ω, ω-tribromomethyl-4-methylquinaldine,
U.S. Pat.
902,903.

Further, there may be mentioned compounds represented by the following general formula (III).

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In the formula, D represents an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms which may be substituted with a halogen atom, X represents a halogen atom, and n represents 1 to 3
Represents an integer.

Specific examples include 2,4-bis (tribromomethyl) -6-methyltriazine, 2,4,6-tris (dibromomethyl) triazine, 2,4,6-tris (tribromomethyl) triazine, , 4,6-tris (trichloromethyl) triazine, 2,4-bis (trichloromethyl) -6-methyltriazine, 2,4-bis (trichloromethyl) -6-phenyltriazine and the like.

Further, a compound represented by the following general formula (IV) is also preferable.

[0133]

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In the formula, Wa represents _a substituted or unsubstituted phenyl group or unsubstituted naphthyl, and the phenyl group is a halogen atom, a nitro group, a cyano group, an alkyl group having 1 to 3 carbon atoms or a carbon atom having 1 carbon atom. It has up to 4 alkoxy groups as substituents. A phenyl group has a structure in which two alkoxy groups form a ring.

[0135]

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It may take the form of The number of substituents is one or two in the case of a halogen atom, but 1 in other cases.
One. Y represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a phenyl group. X represents a halogen atom, and n represents 1
Represents an integer of 1 to 3.

As a specific example, the following JP-A-55-2
There are compounds described in US Pat.

[0138]

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[0139]

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The amount of the photosensitive halogen-containing compound used is such that the halogen radical generated when the photosensitive halogen-containing compound is exposed to light absorbed by the photosensitive halogen-containing compound or the hydrohalic acid generated by the radical decolorizes the merocyanine dye. It is necessary that the amount be sufficient. In general, an appropriate amount is determined by coating at various ratios in combination with a merocyanine dye.
The mole is suitably from 100 to 100 mol, preferably from 1 to 10 mol.

The merocyanine dye preferably used in the present invention has a basic nucleus and an acidic nucleus,

[0142]

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A dye having a resonance structure represented by the following formula and having an absorption band in the photosensitive wavelength region of the heat-developable photosensitive layer.

Preferred merocyanine dyes for use in the present invention have a thiazoline nucleus, an oxazoline nucleus, a pyrroline nucleus, a pyridine nucleus, an oxazole nucleus, a thiazole nucleus, a selenazole nucleus, a tetrazole nucleus or an imidazole nucleus as basic nuclei. Hydantoin nucleus, rhodanine nucleus, oxazolidinedione nucleus, thiazolidione nucleus,
It has a barbituric acid nucleus, thiazoline-on nucleus, malononitrile nucleus or pyrazolone nucleus. These merocyanine dyes are known and include, for example, Mees a
nd James, "The Theory of t
he Photographic Process "3
rd Ed. (1967) PP218-227; M. Hamer, "The Cyanine Dy
es andRelatedCompounds "(1
964) and the like, and the merocyanine dye to be used can be appropriately selected.

In the present invention, the amount of the merocyanine dye used is preferably an amount sufficient to make the transmission optical density of the crossover light blocking layer at least 0.1 or more, especially 0.3 or more.

The following are specific examples of merocyanine dyes particularly suitable for use in the present invention.

[0147]

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[0148]

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[0149]

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[0150]

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[0151]

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As the heat bleaching dye preferably used in the present invention, the reducing dye present in the same image element is reduced by a ketyl group formed from benzopinacol upon heating, whereby the dye is easily bleached. Dye. Therefore, the structure of the heat-bleached crossover light blocking layer preferably used in the present invention comprises a binder, benzopinacol that generates a ketyl group when heated to a temperature of 100 ° C. or more, and a reducing dye or a reducing dye precursor. And a support coated with a neutral or acidic thermal bleachable layer. Benzopinacol, which is usually unstable in a solution, can be blended with a binder in a neutral or acidic layer to make it stable for a long time. While some of the benzopinacol-containing elements described herein require slightly higher temperatures or longer times for ketyl group formation, preferred elements of the invention are 12
Heating at a temperature of 0 ° C. or more for 10 seconds or more is required. The thermogenic ketyl groups react with the aforementioned dyes in a substantially irreversible reaction to provide the desired degree of bleaching permanence.

Many types of benzopinacols can be used in the present invention. Useful benzopinacols produce ketyl groups, which are believed to be due to dissociation reactions upon heating above 100 ° C.

Preferred benzopinacols include:

[0155]

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Wherein R ¹ and R ⁵ are independently halogen atoms such as fluorine, bromine and chlorine; C ^1-10 alkyl, including halogen-substituted alkyls such as chloromethyl; methoxy and ethoxy. Selected from the group consisting of alkoxy having 1 to 10 carbon atoms; phenoxy having 6 to 12 carbon atoms; and a hydroxyl group, wherein R ³ and R ⁷ are independently selected from hydrogen and all the groups defined for R ¹ and R ⁵ above. R ³ , R ⁴ , R ⁷ and R ⁸
Is independently selected from fluorine, bromine and chlorine, preferably a halogen atom which is fluorine; and trifluoromethyl, and both ortho groups of each phenyl group can be substituted only when both substituents are fluorine; Is independently an integer of 1 to 4, and m is independently an integer of 0 to 4.
These substituted benzopinacols generally require only slightly lower activation temperatures, but at the same time maintain long-term stability in the image element.

Combinations of different benzopinacols are also useful in the benzopinacol dye layer.

The highly preferred benzopinacol has the advantages of ease of processing and long life, while retaining other advantages.
It makes ketyl groups more reactive than ketyl groups made from other pinacols. These preferred benzopinacols have the formula

[0159]

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In the formula, R ¹¹ is hydrogen; alkyl having 1 to 16 carbon atoms, for example, alkyl (including cycloalkyl) such as methyl, ethyl and propyl; or substituted aryl such as methoxyphenyl, methylphenyl and the like. R ¹² and R ¹⁶ are independently selected from the group consisting of hydrogen; halogen; and trifluoromethyl; R ¹³ and R ¹⁵ are hydrogen; halogen; Alkyl is selected from the group consisting of alkyl such as methyl, ethyl and propyl, or together with R ¹⁴ represents a tetramethylene group.

R ¹⁴ is hydrogen; halogen; alkyl having 1 to 16 carbon atoms, including cycloalkyl and substituted alkyl, such as alkyl such as methyl, ethyl and propyl; and substituted alkoxy such as methoxyphenoxy or methylphenoxy. It is selected from the group consisting of phenoxy including substituted phenoxy and alkoxy having 1 to 16 carbon atoms, provided that when both ortho positions of the phenyl group to which R ¹² and R ¹⁶ are bonded are substituted, the substituent is fluorine. And

Useful binders for the image forming layer and the benzopinacol containing layer are very extensive. Useful binders are water permeable because the elements of the present invention need not be treated with an aqueous solution. Not necessary, however,
Must be compatible with the benzopinacol and dye used. Compatibility means that it does not adversely affect pinacol or the dye and does not adversely affect the intended imaging properties of the image element. Examples of binders are cellulose ester derivatives such as, for example, alkyl esters or carboxylated cellulose; polyacetals such as polyvinyl butyral and polyvinyl formal; polyvinyl alcohol; various vinyl polymers such as polyvinylidene halide;
There are polymers of α, β-ethylenically unsaturated carboxylic acids such as polymethyl methacrylate. The binder chosen must be able to withstand the processing temperatures used without adversely affecting the desired properties of the layers used. Combinations of various binders are also useful.
Preferred binders are polysulfonamide binders.

Although benzopinacol can be mixed with a wide range of binders to form the bleaching performance of the present invention, a particularly preferred binder is the Res.
arch Disclosure No. 18107. Polysulfonamide binder described in No. 18107. Benzopinacol blended in the polysulfonamide binder exhibits excellent stability even during long-term storage, and exhibits excellent image forming properties. The polysulfone amide is characterized having a maximum absorption wavelength below about 850nm in the spectral range contains a moiety of the -SO ₂ -N <in formula or during its side chain in the main chain, and 200 to 750 nm.

Various sulfonamide polymers having a —SO ₂ —N <group as part of the polymer backbone or as a side chain moiety have a maximum absorption wavelength of less than about 850 nm in the spectral range from 200 to 750 nm. It proved useful on certain conditions. Particularly useful groups of polymers include those containing toluene-2,4-disulfonamide units and those containing N- (vinylphenyl) sulfonamide units. These binders can be homopolymers, copolymers or physical mixtures with polysulfonamide polymers. Whether the polymer is an addition polymer, or Whether a condensation polymer, the smallest portion of the polymer is -SO ₂ -N <in repeated sulfonamide group, therefore sulfur should be at least about 4 wt%.

The binder concentration can be varied over a very wide range. Typically, the weight of any reactive component, including benzopinacol and dye, to the binder should not be greater than about 50%. 50 coatings
To 99% binder,
More preferably, it contains from 80 to 95% of the binder.

Any dye which is known to prevent changes in the electromagnetic radiation absorption properties upon reduction and which can react with the described ketyl groups can be used. As the crossover light blocking layer, for example, it is preferable that the heat bleaching layer has substantially uniform absorption in a spectral region to which the image forming composition is sensitive. The crossover light blocking layer must have at least about 90% of the layers change from colored to colorless or reduced to substantially no concentration.

A wide variety of dyes which are bleached or discolored upon reduction are known. Dyes of this type have long been used in known silver halide photographic materials. For example,
There are cyanine dyes, diphenylmethine dyes, formazan dyes, aminotriarylmethine and thiocyanine dyes. It is necessary that the dye be sufficiently reduced by reacting with a ketyl group formed from benzopinacol upon heating.

Although several groups of reducing dyes and reducing dye precursors are useful in the present invention, the preferred type of reducing dye is an azo dye. because,
Because they are very reactive to the ketyl group and the reaction is irreversible. Having one or more azo groups and having the formulas Ar-N = N-Ar and Ar-N =
N-Ar-N = N-Ar-N = N-Ar, where Ar represents an aromatic group that can contain any substituents well known in the art of azo dyes. ,
Any azo dye is useful. These substituents include: alkyl; aryl; cyano; halogen; halogen-substituted alkyl and aryl, such as trifluoromethyl; alkyl or arylsulfonyl, such as ethylsulfonyl and methylsulfonyl; alkoxy, such as methoxy and ethoxy; Nitro; substituted amino such as diethylamino and dimethylamine, and the like. Dyes belonging to this class include azo dyes such as monoazo and diazo dyes having amino, pyrazolone, hydroxy, alkoxy and other substituents and diazo dyes having stilbene and triphenylmethane linkages.

The benzopinacol dye layer of the element of the present invention must be neutral or acidic. To provide a neutral layer or the desired degree of acidity, an acid, typically an organic acid,
An inorganic acid or Lewis acid can be added to the coating composition before coating. Useful acids include sulfonic acid, acetic acid,
There are hydrochloric acid, aluminum chloride and the like. In some embodiments, such an acid may not be used because the binder itself provides the necessary acidity to the layer.

The types and ratios of the various components forming the benzopinacol dyes of the present invention can vary very widely depending on the application. For the crossover light blocking layer, it is preferred that the dye be present in an amount sufficient to provide an optical density of about 0.3 to 0.8, and that benzopinacol be present in at least a stoichiometric amount. For example, when using an azo dye, the stoichiometric amount is 2 moles of benzopinacol per mole of azo dye. Typically, an excess of benzopinacol will ensure complete reduction of the azo dye in practice. The upper limit of the ratio of benzopinacol to azo dye is determined from an economic point of view and can be 80: 1. The preferred ratio is from about 1: 1 to 4: 1, with the optimal ratio for complete reduction being about 2.4: 1.

The heat bleachable layer and other layers of the element of the present invention can be coated using any of the various methods known in the photographic art such as doctor blade coating, hopper coating, dipping, jet printing and the like. It can be performed.

Dyes useful in the present invention can be mordant to prevent migration to undesirable locations in the image element. Any of a wide variety of mordants known in the photographic art can be used.

In the present invention, the unit for forming an X-ray image is a unit in which a surface having a photosensitive layer and a fluorescent intensifying screen are brought into close contact with each other to imagewise expose the photosensitive material of the present invention by X-ray irradiation. Say

When the silver halide photographic light-sensitive material of the present invention is applied to medical X-ray radiography, for example, a fluorescent material mainly composed of a phosphor which generates near-ultraviolet light or visible light upon exposure to penetrating radiation. An intensifying screen is used. This is brought into close contact with both surfaces of a light-sensitive material obtained by coating the emulsion of the present invention on both surfaces and exposed. Here, the penetrating radiation is a high-energy electromagnetic wave and means X-rays and γ-rays.

First, the fluorescent intensifying screen according to the present invention will be described. Usually, the radiographic intensifying screen has a configuration in which a phosphor layer is provided on the surface of a support. The phosphor layer absorbs X-rays and emits visible light. For a photosensitive material, by converting the fluorescent intensifying screen into high-sensitivity visible light, the sensitivity of the X-ray imaging system can be significantly improved and the radiation dose can be reduced. The fluorescent intensifying screen can be produced, for example, by the following method.

The support can be appropriately selected from various materials used as supports for intensifying screens (or X-ray intensifying screens) in conventional X-ray photography. Examples of such materials include plastic films such as cellulose acetate and polyethylene terephthalate, metal sheets such as aluminum foil, ordinary paper, baryta paper, and resin-coated paper. When a plastic film is used as the support, a light-reflective substance such as titanium dioxide may be kneaded in the film, or a light-absorbing substance such as carbon black may be kneaded in the film.

The surface of the support of the X-ray intensifying screen provided with the phosphor layer is provided with an adhesion imparting layer, a light reflecting layer,
A light absorbing layer or the like may be provided.
As described in Japanese Patent Application Laid-Open No. 182599, fine irregularities may be uniformly formed (the irregularities may be formed on the surface of the support on the side of the phosphor layer, the adhesion imparting layer, the light reflecting layer, and the light absorbing layer). Is formed on the surface thereof.)

Next, a phosphor layer is formed on the support of the X-ray intensifying screen. This phosphor layer is a layer that can be composed of a binder such as gelatin that contains and supports the phosphor particles in a dispersed state.

The phosphor used in the practice of the present invention is X
Phosphors that emit in the blue region of about 350-500 nm when excited by radiation such as radiation are preferred. An example of such a blue-emitting phosphor is disclosed in JP-A-55-28095.
And JP-A Nos. 4-300993 and 4-300994.

Further, in the present invention, a fluorescent intensifying screen containing a yttrium tantalate-based phosphor and / or a barium halide-based phosphor as a main component is preferably used. These phosphors may be used alone or in combination of two or more. In the present invention, the ratio of the phosphor contained in the intensifying screen is such that at least 50% or more, more preferably 80% or more, and most preferably 100% of the above-mentioned phosphor is contained. It is preferable in terms of graininess and sharpness when combined with a photosensitive material.

The method for producing an intensifying screen in the present invention can be produced by a known means described in JP-A-5-273706 and JP-A-7-209496. For example, it can be manufactured as follows.

That is, the phosphor particles and a binder such as gelatin are added to an appropriate solvent (eg, lower alcohol, hydrocarbon containing a chlorine atom, ketone, ester, ether), and the mixture is mixed well to form a binder. A coating solution in which the phosphor is uniformly dispersed in the solution is prepared.

Examples of the binder are represented by proteins such as gelatin, and synthetic high molecular substances such as polyvinyl acetate, nitrocellulose, polyurethane, polyvinyl alcohol, polyalkyl (meth) acrylate, linear polyester and the like. Binders can be mentioned.

The mixing ratio between the binder and the phosphor in the coating solution is usually preferably in the range of (1: 8) to (1:40) (weight ratio). After a coating film of the coating solution is formed by uniformly applying the coating solution on the surface of the support, the coating film is dried to complete the formation of the phosphor layer on the support. The thickness of the phosphor layer is generally 50 to 500 μm.

Further, a transparent protective layer for physically and chemically protecting the phosphor layer may be provided on the surface of the phosphor layer opposite to the side in contact with the support. Examples of the material used for the transparent protective layer include cellulose acetate, polymethyl methacrylate, polyethylene terephthalate, and polyethylene. The thickness of the transparent protective layer is usually about 3 to 20 μm.

[0186]

EXAMPLES The present invention will be described below in detail with reference to examples, but embodiments of the present invention are not limited thereto.

Example 1 (Preparation of Support 1) A color of 0.170 (densitometer PDA-65 manufactured by Konica Corporation) was colored blue and had a thickness of 17
A corona discharge treatment of 8 W / m ² · min was applied to both sides of a 5 μm PET film to prepare a support 1.

(Preparation of Support 2) As in the case of Support 1, PEN having a thickness of 175 μm and a blue color with a concentration of 0.170 was used.
A corona discharge treatment of 8 W / m ² · min was applied to both sides of the film, and a support 2 was produced.

(Preparation of Photosensitive Silver Halide Emulsion a) Water 9
6. Ossein gelatin having an average molecular weight of 100,000 in 00 ml
5 g and 10 mg of potassium bromide were dissolved at a temperature of 35 ° C.
After adjusting the pH to 3.0, 370 ml of an aqueous solution containing 74 g of silver nitrate, an aqueous solution containing potassium bromide and potassium iodide in a molar ratio of (98/2), and iridium chloride were added at 1 × 10 ^-4 mole per mole of silver. Was added over 10 minutes by the controlled double jet method while maintaining the pAg at 7.7. Thereafter, 4-hydroxy-6-methyl-1,3,3
a) Cubic silver iodobromide having an average grain size of 0.06 μm, a grain size variation coefficient of 12%, and a [100] face ratio of 87% by adjusting the pH to 5 with NaOH and adding 0.3 g of 7-tetrazaindene. Particles 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 to obtain a photosensitive silver halide emulsion. The above-mentioned photosensitive silver halide emulsion was dissolved at 55 ° C., 1.0 × 10 ⁻⁴ mol / mol Ag of sodium thiosulfate was added, and the mixture was stirred for 10 minutes. 10 ^-5 mol / mol Ag is added and 20 ° C
To complete the chemical sensitization to prepare a photosensitive silver halide emulsion a.

(Preparation of Powdered Organic Silver Salt A) 111.4 g of behenic acid and 83.8 of arachidic acid were added to 4720 ml of pure water.
g and 54.9 g of stearic acid were dissolved at 80 ° C. Next, while stirring at a high speed, 540.2 ml of a 1.5 M aqueous sodium hydroxide solution was added, and 6.9 ml of concentrated nitric acid was added.
Upon cooling to 55 ° C., a sodium organic acid solution was obtained.

The temperature of the above-mentioned organic acid sodium solution was 55
While maintaining the temperature, the photosensitive silver halide emulsion a (containing 0.038 mol of silver) and 450 ml of pure water were added and stirred for 5 minutes. Next, 760.6 ml of a 1 M silver nitrate solution was added to 2
The mixture was added over a period of 20 minutes, stirred for another 20 minutes, and the water-soluble salts were removed by filtration. Thereafter, the conductivity of the filtrate was 2 μS /
The powder was repeatedly washed with deionized water and filtered until centrifugation, and centrifugally dehydrated, followed by hot-air drying at 37 ° C. until the weight was no longer reduced.

(Preparation of photosensitive emulsion dispersion) Polyvinyl butyral powder (Butvar B manufactured by Monsanto)
-79) 14.57 g of methyl ethyl ketone 1457 g
And, while stirring with a dissolver-type homogenizer, 500 g of powdered organic silver salt A was gradually added and mixed well. Thereafter, dispersion was performed at a peripheral speed of 13 m and a residence time in the mill for 0.5 minute with a media type disperser (manufactured by Gettzmann) filled with 80% of 1 mm Zr beads (manufactured by Toray) to prepare a photosensitive emulsion dispersion.

<Preparation of Sensitizing Dye Liquid> The following spectral sensitizing dyes (A) and (B) were dissolved in methanol at a ratio of 4: 6. At this time, the sensitizing dye (A) was adjusted to have a concentration of 0.2%.

Sensitizing dye (A): 5,5'-di-chloro-
9-ethyl-3,3'-di- (3-sulfopropyl) oxacarbocyanine-sodium salt anhydride Sensitizing dye (B): 5,5'-di- (butoxycarbonyl) -1,1'-diethyl -3,3'-Di- (4-sulfobutyl) benzimidazolocarbocyanine-sodium salt anhydride <Preparation of stabilizer solution> To 1.0 g of stabilizer 1, 0.5 g of potassium acetate and 8.5 g of methanol After dissolution, a stabilizer solution was prepared.

<Preparation of Antifoggant Solution> Antifoggant 2
5.81 g, dissolved in MEK, finished to 100 ml,
An antifoggant solution was used.

(Preparation of Coating Solution for Photosensitive Layer) The above-mentioned photosensitive emulsion dispersion (50 g) and 15.11 g of MEK were kept at 21 ° C. while stirring, and 390 μl of antifoggant 1 (10% methanol solution) was added, followed by 1 hour. Stirred. Further, 889 μl of calcium bromide (10% methanol solution) was added, and the mixture was stirred for 30 minutes. Next, the sensitizing dye solution was added to 1.41.
After adding 6 ml and 667 μl of the stabilizer solution and stirring for 1 hour, the temperature was lowered to 13 ° C. and further stirred for 30 minutes.

While keeping the temperature at 13 ° C., polyvinyl butyral (Monvarto Butvar B-79) was used.
After adding 13.31 g and stirring for 30 minutes, the following additives were added at intervals of 15 minutes while stirring was continued.

Developer: 150 mg phthalazine or compound of general formula (1): (the amount added is shown in Table 1) Tetrachlorophthalic acid: 102 mg 4-methylphthalic acid: 137 mg After adding the above and stirring for 15 minutes, fog prevention Chemical solution: 5.47 ml Desmodur N3300 (Mobay, Inc., aliphatic isocyanate) 10% MEK solution: 1.60 ml was added sequentially and stirred to obtain a photosensitive layer coating solution.

[0199]

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The following layers were sequentially formed on a support to prepare a light-sensitive material. The drying was performed at 75 ° C. for 5 minutes.

<Photosensitive layer> A photosensitive layer was prepared in the same manner as the photosensitive layer except that the developer was not used.

(Preparation of Coating Solution for Protective Layer) <Surface Protective Layer> A solution having the following composition was coated on the photosensitive layer.

Methyl ethyl ketone 17 ml / m ² Cellulose acetate 2.3 g / m ² Matting agent: Monodispersity 10% Average particle size 4 μm Monodispersed silica 70 mg / m ² Developer: 0.1 g / m ² <Surface protective layer> Development A surface protective layer was prepared in the same manner as the surface protective layer except that the agent was not used.

(Preparation of double-sided photosensitive coated sample) The photosensitive layer coating solution and the surface protective layer were coated on one side of the support so that the coated silver amount was 1.5 g / m ² . Coating was performed on the back surface in the same layer configuration, and coating samples 1 to 8 described in Table 1 were applied.
Was prepared.

(Production of Fluorescent Intensifying Screen 1) Fluorescent intensifying screen 1: <Yttrium tantalate fluorescent intensifying screen> Particles of YTaO ₄ and a linear polyester resin (Vylon #
500: manufactured by Toyobo Co., Ltd.), methyl ethyl ketone was added, and nitrocellulose having a nitrification degree of 11.5% was further added to prepare a dispersion liquid containing phosphor particles in a dispersed state.

Next, tricresyl phosphate, n-
Butanol and methyl ethyl ketone were added. After that, mix well with a propeller mixer,
The phosphor particles are uniformly dispersed, the mixing ratio between the binder and the phosphor is 1:20 (weight ratio), and the viscosity is 25 to 35 PS (2
(5 ° C.).

Next, a coating solution was uniformly applied on a polyethylene terephthalate film (support thickness: 250 μm) kneaded with white pigment horizontally placed on a glass plate using a doctor blade. After the coating, the support on which the coating film was formed was placed in a dryer, and the temperature inside the dryer was reduced to 25%.
C. to 100.degree. C., and the coating was dried. Thus, a phosphor layer having a thickness of about 180 μm was formed on the support.

Next, a transparent film of polyethylene terephthalate (thickness: 12 μm, to which a polyester-based adhesive is applied) is placed on the phosphor layer with the adhesive layer side facing down, and adhered to the phosphor layer. A protective film was formed, and a radiation fluorescent intensifying screen 1 comprising a support, a phosphor layer, and a transparent protective film was manufactured.

<Evaluation of sensitometry> 3.5 cm ×
The coated samples 1 to 8 cut to 30 cm are sandwiched between the fluorescent intensifying screens 1 from both sides such that the fluorescent surfaces are in close contact with the coated samples,
X-ray irradiation was performed via a penetrometer type B (manufactured by Konica Medical Inc.).

Thereafter, heat development was performed at 120 ° C. for 15 seconds using an automatic developing machine having a heat drum and a metal back roll. Further, the sample No. For 4 and 5, 1k
The colored portion was decolorized by irradiating with a W high pressure mercury lamp at a distance of 10 cm for 12 seconds. At that time, exposure and development were performed in a room conditioned at 23 ° C. and 50% RH. The obtained image was evaluated using a densitometer. The results of the measurement were evaluated by sensitivity (reciprocal of the ratio of the exposure amount giving a density higher than that of the unexposed portion by 1.0) and fog.

<Evaluation of Raw Preservation> 3.5 cm × 30 cm
Each of the coated samples 1 to 8 cut into two pieces was cut into two pieces.
One sheet at 25 ° C, 55% for 3 days, the other at 55 ° C, 55%
% For 3 days, and then developed without exposure, in the same manner as in the evaluation of sensitometry. Table 2 shows ΔDmin obtained by the following calculation formula.

ΔDmin = Dmin (stored at 55 ° C., 55% for 3 days) −Dmin (stored at 25 ° C., 55% for 3 days).

<Evaluation of Silver Tone> Each of the coated samples cut into 25 cm × 30 cm was exposed and developed in the same manner as in the sensitometry process. Then, a five-step evaluation was performed as follows. Table 2 shows the results.

5: No yellowishness and cool black tone 4: Slightly yellowish, but barely noticeable 3: Yellowish, but practically acceptable 2: Strong yellowishness, which is problematic for practical use 1: Yellowishness is remarkably strong, and is not practically suitable.

<Evaluation of Sharpness> A: Very sharp B: Good but slightly blurred C: Blur is noticeable and there is some difficulty in image interpretation D: Difficult to interpret due to blur.

[0216]

[Table 1]

[0219]

[Table 2]

From Table 2, it can be seen that the sample of the present invention has sufficient sensitivity, low fog, and good raw storability, residual color and sharpness of the photographic material.

Example 2 (Preparation of Coating Solution for Photosensitive Layer) The photosensitive emulsion dispersion liquid (50 g) prepared in Example 1 and 15.11 g of MEK were kept at 21 ° C. while stirring, and an antifoggant 1 (10% methanol 390 μl) and stirred for 1 hour. Further, 889 μl of calcium bromide (10% methanol solution) was added, and the mixture was stirred for 30 minutes.

Next, the sensitizing dye solution prepared in Example 1 was used.
416 ml and 667 μ of the stabilizer liquid prepared in Example 1.
After stirring for 1 hour, the temperature was lowered to 13 ° C., and the mixture was further stirred for 30 minutes. While keeping the temperature at 13 ° C., polyvinyl butyral (Monsanto Butva)
(rB-79) 13.31 g was added and stirred for 30 minutes, and then the following additives were added at 15-minute intervals while stirring was continued.

Phthalazine: 305 mg Tetrachlorophthalic acid: 102 mg 4-Methylphthalic acid: 137 mg After adding the above and stirring for 15 minutes, antifoggant solution: 5.47 ml Developer solution: 14.06 ml Desmodur N3300 (Mobay, Inc., aliphatic) Isocyanate) 10% MEK solution: 1.60 ml was sequentially added and stirred to obtain photosensitive layer coating solution 1.

The preparation of the above developer solution is as follows.

17.74 g of a developer was dissolved in MEK, and
Finished to 00 ml to make a developer solution.

The following layers were sequentially formed on a support to prepare a light-sensitive material. The drying was performed at 75 ° C. for 5 minutes.

<Crossover Light Blocking Layer> A crossover light blocking layer was provided below the photosensitive layer on both sides of the (COC-1) support so as to have the following amounts.

Polyvinyl butyral 2 g / m ² Merocyanine dye (29) 30 mg / m ² Photosensitive halogen-containing compound (6) 60 mg / m ² (COC-2) A crossover light blocking layer was provided so that

Polyvinyl butyral 2 g / m ² Merocyanine dye (29) 30 mg / m ² Photosensitive halogen-containing compound (19) 60 mg / m ² (COC-3) A crossover light blocking layer was provided so that

Polysulfonamide 1 g / m ² N, N-dimethyl-p- (nitrophenylazo) aniline 10 mg / m ² Toluenesulfonic acid 300 mg / m ² 2,3,4,5,6,2 ′, 3 ′, 4 ', 5', 6'-Decafluorobenzopinacol 200 mg / m ² (COC-4) A crossover light blocking layer was provided below the photosensitive layer on both sides of the support so as to have the following coverage.

Polysulfonamide 1 g / m ² N, N-dimethyl-p- (nitrophenylazo) aniline 20 mg / m ² Toluenesulfonic acid 300 mg / m ² 2,3,4,5,6,2 ′, 3 ′, 4 ′, 5 ′, 6′-Decafluorobenzopinacol 400 mg / m ² <Surface protective layer> A solution having the following composition was coated on the photosensitive layer.

Methyl ethyl ketone 17 ml / m ² Cellulose acetate 2.3 g / m ² Matting agent: Monodispersity 10% Average particle size 4 μm Monodispersed silica 70 mg / m ² (Preparation of double-sided photosensitive coating sample) One of the supports Coated with the above-mentioned photosensitive layer coating solution and a surface protective layer, and coated silver amount 1.5 g / m 2
After the application was performed so as to be ² , the coating was applied to the back surface of the support with the same layer configuration to prepare Application Samples 11 to 15 shown in Table 3.

<Production of Fluorescent Intensifying Screen ₂ > Phosphor Gd ₂ O ₂ S: Tb (average particle size: 1.8 μm) 200 g Combined polyurethane thermoplastic elastomer Demolac TPKL-5-2625 40% solid content [Sumitomo Bayer Urethane Co., Ltd.] 20 g Nitrocellulose (nitrification: 11.5%) 2 g A methyl ethyl ketone solvent was added to the above and dispersed with a propeller mixer to prepare a coating solution for forming a phosphor layer having a viscosity of 25 ps (25 ° C.). (Binder / Phosphor ratio = 1/2)
2).

Separately, 90 g of soft acrylic resin solids and 50 g of nitrocellulose were separately used as a coating solution for forming an undercoat layer.
Is added with methyl ethyl ketone, dispersed and mixed to obtain a viscosity of 3 to 3.
A 6 ps (25 ° C.) dispersion was prepared.

A thickness of 250 μm into which titanium dioxide has been kneaded.
The polyethylene terephthalate base (support) was placed horizontally on a glass plate, and the coating solution for forming an undercoat layer was uniformly applied on the support using a doctor blade.
To 100 ° C. to dry the coating film to form an undercoat layer on the support. The thickness of the coating film is 15 μm
Met.

The above-mentioned coating solution for forming a phosphor layer was uniformly coated with a doctor blade to a thickness of 240 μm and dried, and then compressed. Compression was performed using a calender roll at a pressure of 800 kgw / cm ² and a temperature of 80 ° C. After this compression, Example 1 of JP-A-6-75097 was used.
A transparent protective film having a thickness of 3 μm was formed by the method described above, and a fluorescent intensifying screen 2 was manufactured.

The sensitometry, raw storage stability and sharpness were evaluated by the method of Example 1 and are shown in Table 4.

<Evaluation of Residual Color Contamination> Each of the coated samples cut into a size of 25 cm × 30 cm was subjected to the same developing treatment as in the sensitometry process. Five-stage evaluation was performed as follows.
Table 4 shows the results.

5: no residual color contamination and good 4: almost slight residual color contamination but almost good 3: somewhat residual color contamination, but at a practical level 2: some residual color contamination, but practical Within the limit of range 1: Plenty of residual color contamination, impractical

[0238]

[Table 3]

[0239]

[Table 4]

From Table 4, it can be seen that the sample of the present invention has sufficient sensitivity, low fog, and good raw storability, residual color and sharpness of the photographic material.

[0241]

The sample of the present invention has sufficient sensitivity, low fog, and good raw preservability, residual color and sharpness of the photographic material.

Claims (11)

[Claims] 1. A photothermographic material having a layer containing an organic silver salt, a photosensitive silver halide and a reducing agent for silver ions on both sides of a support made of polyethylene naphthalate. . 2. The photothermographic material according to claim 1, wherein the photosensitive silver halide is chemically sensitized with a chalcogen compound. 3. The photothermographic material according to claim 1, wherein the reducing agent is contained in a layer different from the layer containing the photosensitive silver halide. 4. The photothermographic material according to claim 1, which comprises at least one compound represented by the following general formula (1). Embedded image [Wherein, W _{1 to} W ₄ are each independently a hydrogen atom or 1
Represents a monovalent substituent, and at least one of W _{1 to} W ₄ is a monovalent substituent. ] 5. A photothermographic material having a layer containing an organic silver salt, a photosensitive silver halide, and a reducing agent for silver ions on both sides of a support, wherein at least one of the layers on the support is provided. A heat-developable photographic material comprising at least one dye which is bleached by heat or light in one layer or in the support, or both. 6. The organic silver salt comprises a long-chain fatty acid silver, and the ratio of the long-chain fatty acid silver to the fatty acid is 85:15 to 100:
6. The photothermographic material according to claim 1, wherein the value is 0. 7. The photothermographic material according to claim 1, wherein the photosensitive silver halide comprises silver iodobromide grains containing 0.5 mol% or more of iodine. . 8. An X-ray, wherein the photothermographic material according to claim 1 is brought into close contact with a phosphor screen of an X-ray intensifying screen having rare earth phosphor particles. Image forming unit. 9. The X-ray image forming unit according to claim 8, wherein the X-ray intensifying screen has a maximum emission spectrum by X-rays in a range from 200 nm to 500 nm. 10. An image recording method, wherein an image is obtained by exposing an X-ray to the X-ray image forming unit according to claim 8 using an X-ray generator as a light source. 11. An image forming method, wherein an image is obtained by heating a photothermographic material having an image recorded thereon by the image recording method according to claim 10 to 100 to 150 ° C.