JP2001109101A - Heat developable sensitive material and x-ray image forming unit and x-ray image recording method each using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a heat developable sensitive material containing a dye and free from color stain due to the remnants of the dye after heat development and to provide an X-ray image forming unit and an X-ray image recording method each using the sensitive material. SOLUTION: The heat developable sensitive material has at least one heat developable photosensitive layer containing photosensitive silver halide on each of both sides of the support and contains a dye which is bleached under heat or light in the photosensitive layer or at least in one layer between the photosensitive layer and the support. Each of the photosensitive layer and the dye- containing layer is formed by coating with a coating fluid in which water occupies >=30% of all solvents.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photothermographic material, an X-ray image forming unit using the same, and an X-ray image recording method, and more particularly, to a dye which is bleached by heat or light after exposure and image recording. In a photosensitive layer or at least one layer between a photosensitive layer and a support, an X-ray image forming unit using the same, an X-ray image recording method, 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 photothermographic material which forms a photographic image by using a heat development processing method is exemplified. For example, see US Pat. No. 3,152,9.
No. 04, 3,457,075, and D.I. Morgan and B.A. "Silver System Treated by Heat (Thermall) by Shelly
y Processed Silver System
s) "(Imaging Processes and Materials
d Materials) Neblette 8th edition,
Sturge, V.S. Wallworth (Wa
lworth), A.I. Shepp, page 2, 1969).

In such a photothermographic material, 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 are usually dispersed in a (organic) binder matrix. It is contained in a state. The photothermographic material is stable at room temperature, but generates silver through an oxidation-reduction reaction between a reducible silver source (which functions 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 contrasts with the unexposed areas, resulting in the formation of an image.

However, in this method, silver halide must be used which is smaller than that of a conventional wet-processed light-sensitive material, so that the photographic sensitivity is extremely low, and it has not been applied to medical X-ray photography. There is no example done.

[0006] However, considerable sensitivity is obtained by increasing the grain size of the silver halide to such an extent that the developability is not significantly impaired, applying chemical sensitization, and further enhancing the developability by making sufficient contact with an organic silver salt. For example, Japanese Patent Application Laid-Open No. 10-282602 describes that it is possible to use the intensifying screen for direct photographing due to an increase in luminous efficiency from the intensifying screen side.

Further, when a photosensitive material is used in combination with a fluorescent screen as a medical X-ray photographing material, the photosensitive material is exposed from both sides, but if the exposure is performed from both sides, the image is blurred due to crossover light. Therefore, it is usually necessary to provide a dye layer for blocking crossover light.
It is common in light-sensitive materials. The dye is preferably bleached or decolored immediately after exhibiting its effect at the time of exposure.
It hinders diagnosis. Since the X-ray photosensitive material obtained by the solution processing is processed in the processing solution, even if the crossover cut dye remains, it flows out into the processing solution and does not remain in the photosensitive material. However, in the photothermographic material, the dye must be completely decolorized or removed after the exposure and before the heat development.

Decolorizing dyes are also used in heat-developable photosensitive materials to prevent sharpness deterioration due to halation or the like. In this case, decolorization of these dyes still poses a problem. Usually, a dye that is easily decolorized by heat is selected, but decolorization may be insufficient due to fluctuations in heat development conditions and the like. In order to solve such a problem, a decoloring agent is added to the layer in order to accelerate the decolorization of the dye and complete the decoloring.

However, since such a dye exists in the layer in the vicinity of the decoloring agent, there is a disadvantage that the decoloring proceeds during storage before exposure. Residuals of these dyes cause diagnostic problems, especially in medical applications, and need to be fully resolved.

[0010]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a photothermographic material which is free from color contamination due to the residual dye after photothermographic processing of a photothermographic material having a dye, and an X-ray image using the same. An object is to obtain a forming unit and an X-ray image recording method.

[0011]

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

1. At least one on each side of the support
In a photothermographic material having a photothermographic layer containing a photosensitive silver halide layer, a dye which is bleached by heat or light is contained in at least one layer between the photosensitive layer or the photosensitive layer and the support. And a photothermographic material, wherein the photosensitive layer and the dye-containing layer are coated using a coating solution in which 30% or more of the solvent is water.

2. 2. The photothermographic material according to the above item 1, wherein the photosensitive silver halide is spectrally sensitized with a sensitizing dye so that the maximum photosensitive wavelength is 300 nm or more and 600 nm or less.

3. 3. The photothermographic material according to the above item 1 or 2, wherein the photosensitive silver halide is chemically sensitized with a noble metal or a chalcogen compound.

4. (4) The photothermographic material as described in (1), (2) or (3) above, further comprising at least one compound represented by the general formula 1.

[0016]

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[In the formula, Hal ₁ and Hal ₂ represent a halogen atom. Hal ₁ and Hal ₂ may be the same or different. X represents an anionic group. R ₁ represents a group having a carbonyl group as a partial structure, and R ₂ and R ₃ represent a substituent which can be substituted on a nitrogen atom or a hydrogen atom. R _{1 to} R ₃
Are not bonded to each other so as to form a ring structure in which the nitrogen atoms become ring atoms. n represents 1 or 2. ] 5. 5. An X-ray image forming unit, wherein the photothermographic material according to any one of 1 to 4 above is brought into close contact with a phosphor screen of an X-ray intensifying screen having rare earth phosphor particles.

6. 6. The X-ray image forming unit according to the item 5, wherein the X-ray intensifying screen has an emission spectrum by X-rays of 300 nm or more and 600 nm or less.

[7] 7. An X-ray image recording method, wherein an image is obtained by irradiating an X-ray to the X-ray image forming unit described in 5 or 6 above using an X-ray generator as a light source.

8. 7. The photothermographic material, on which an image has been recorded by the X-ray image recording method described in 7 above,
An image forming method characterized in that an image is obtained by heating to ° C.

The photothermographic material has a photosensitive layer containing a non-photosensitive organic silver salt, a photosensitive silver halide and a reducing agent usually in a state of being dispersed in an organic binder matrix. These photothermographic materials are stable at room temperature, but when heated to a high temperature after exposure, dissolution physical development (organism) in the photosensitive layer using the latent image on the photosensitive silver halide generated by exposure as a catalyst nucleus is performed. Silver is generated by a redox reaction between a silver salt (functioning as an oxidizing agent) and a reducing agent.

As described above, the present invention can be achieved by using a photothermographic material containing a dye which is bleached by heat or light after exposure in a photosensitive layer or any one layer between a photosensitive layer and a support.

In the present invention, the layer containing a dye which is bleached by heat or light is, in the case of an X-ray photographic material, a dye layer which is bleached by heat or light, so that it can be subjected to heat development during image exposure. By absorbing and blocking light from the fluorescent intensifying screen passing through the layer, sharpness of the light-sensitive material is improved. These layers effectively act as so-called cross-over light blocking layers from the opposite side of the support in the case of an X-ray photographic material having a photosensitive layer on both sides of the support.

In the present invention, a dye which is bleached by light is heated and developed, and the entire surface of the dye is exposed to light, and a photosensitive halogen-containing compound is used as a decolorizing agent for decolorizing the dye.
A dye which is decolorized by the action of a halogen radical or hydrohalic acid generated by the photolysis, and a preferable dye is a merocyanine dye. Further, a method of decoloring and making transparent using such a halogen-containing compound and a merocyanine dye is preferably used.

Another bleaching dye of the present invention is a heat bleaching dye. This is a reducing dye that is reduced by a ketyl group formed from benzopinacol during heating, and is a decolorizing method using a reducing dye.

As a result, the dye does not decolorize during storage, and bleaching of the dye occurs due to halogen radicals or ketyl groups generated only when the dye is exposed to light or heat. Not an effective crossover light-cut dye.

The preferred binder for these light and heat bleached dye layers is an aqueous binder. Japanese Patent Application No. 1
No. 1-196657 also discloses a technique for a crossover light blocking layer having a dye which is bleached by light and heat, but in the present invention, an aqueous binder is used, and 30% or more of a solvent is water. By using one coated with a certain coating solution, the dye of the present invention that is bleached by light and heat is stably present as a fine particle dispersion in the layer, causing an unnecessary reaction before exposure to bleach the dye. And that the halogen-containing compound and pinacol do not cause unnecessary reactions and do not adversely affect the performance of the photothermographic material. The aqueous binder polymer will be described later in detail.

The photosensitive halogen-containing compound, which is one element of the photobleachable coloring composition preferably used in the crossover light-shielding layer of the present invention, decomposes upon irradiation with light to release halogen radicals or hydrohalic acid. Organic compounds. Such compounds are described, for example, in U.S. Pat. No. 3,902,903, British Patent 1,432,138.
JP-A-50-120328, JP-A-50-120328
Many such compounds are known from, for example, 19624 and 55-24113, and in the present invention, any of such known photosensitive halogen-containing compounds can be appropriately selected and used.

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

[0030]

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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,

[0033]

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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:

[0035]

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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,

[0037]

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Wherein R ₈ has 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:

[0039]

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

[0041]

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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).

[0044]

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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).

[0048]

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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.

[0052]

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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.

[0054]

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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.

[0057]

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[0058]

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The amount of these photosensitive halogen-containing compounds used is such that halogen radicals generated when exposed to light absorbed by these photosensitive halogen-containing compounds or hydrohalic acid generated by the radicals decolorize the dye. Need to be sufficient.

As the dye used together with the photosensitive halogen-containing compound, any dye can be used as long as it is bleached by a halogen radical generated by photolysis of the photosensitive halogen-containing compound or hydrohalic acid generated by the radical. Although good, preferred dyes include merocyanine dyes. Although the amount of the halogen-containing compound generally varies depending on the combination with the dye used together, it is preferable to determine the appropriate amount by coating at various ratios. In the case of a merocyanine dye, the amount of the photosensitive halogen-containing compound is generally 0.1 mol to 100 mol, preferably 1 mol to 10 mol, per 1 mol of the merocyanine dye.

The merocyanine dyes preferably used together with these are as follows.

The merocyanine dye has a basic nucleus and an acidic nucleus,

[0063]

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

The merocyanine dye preferred for use in the present invention has 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 a basic nucleus. It has a hydantoin nucleus, rhodanine nucleus, oxazolidinedione nucleus, thiazolidione nucleus, barbituric acid nucleus, thiazoline on nucleus, malononitrile nucleus or pyrazolone nucleus. These merocyanine dyes are known, for example, Mees
and James, "The Theory of
the Photographic Procedures
s "3rd Ed. (1967) PP218-227;
Or F. M. By Hamer, "The Cyanine
Dyes and RelatedCompound
The merocyanine dye to be used can be appropriately selected with reference to the description such as s "(1964).

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.

[0068]

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[0069]

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[0070]

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[0071]

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[0072]

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As the heat bleaching dye preferably used in the present invention, a reducing dye present in the same image element is reduced by a ketyl group formed from benzopinacol upon heating, whereby the dye is easily prepared. It is a dye that is bleached. 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 require heating at a temperature of 120 ° C. or higher for 10 seconds or longer. Is done. 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:

[0076]

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Wherein R ¹ and R ⁵ are independently halogen atoms such as fluorine, bromine and chlorine; alkyls having 1 to 10 carbon atoms 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 ² , R ⁴ , R ⁶ 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.

[0079] 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

[0080]

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Is represented by

Wherein 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, for example, 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

Any dye which is known to prevent a change 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 that 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
Any azo dye represented by -Ar-N = N-Ar, where Ar represents an aromatic group that can contain any substituents well known in the azo dye art. Is also 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 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.

In the present invention, silver halide grains function as an optical sensor. In a heat development system, the average grain size is preferably smaller in order to suppress the 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 the 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).

Further, 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 used in the present invention is 0.5 mol.
%, More preferably 0.7 mol% or more and 5 mol% or more.
It is as follows. 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 for the purpose of improving illuminance failure and adjusting the improvement. As the above metals, W, Fe, Co, Ni,
Cu, Ru, Rh, Pd, Re, Os, Ir, and Pt are preferable. These metal ions may be introduced into a silver halide in the form of a metal complex or a complex ion. Can be introduced. 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,-, 2-, 3- or Represents 4-. Specific examples of the ligand represented by L include:
Halides (fluoride, chloride, bromide and iodide),
Examples include cyanide, cyanate, thiocyanate, selenocyanate, tellurocyanate, azide, and aquo ligands, nitrosyl, thionitrosyl, and the like, and 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 transition metal complex ions.

[0098] 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 can be added by dissolving them in water or a suitable organic solvent (eg, alcohols, ethers, glycols, ketones, esters, amides). A method of adding an aqueous solution of a powder or an aqueous solution in which a metal compound and NaCl and KCl are dissolved together to a water-soluble silver salt solution or a water-soluble halide solution during grain formation, or a method in which a silver salt solution and a halide solution are used. When they are mixed simultaneously, they are added as a third aqueous solution to prepare silver halide grains by a three-liquid simultaneous mixing method, a method in which a required amount of an aqueous solution of a metal compound is charged into a reaction vessel during grain formation, or a method in which halogen is added. There is a method in which another silver halide grain doped with a metal ion or a complex ion in advance at the time of preparing silver halide is added and dissolved. 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, but in the present invention, they may or may not be desalted. Good.

In the present invention, the photosensitive silver halide is preferably chemically sensitized with a noble metal or a chalcogen compound.

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 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, selenium compounds disclosed in conventionally known patents 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 (eg, tri Phenylphosphine selenide), colloidal metal selenium, and the like.

The preferred types of unstable selenium compounds have been described above, but these are not limitative. 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.

The 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.

Examples of 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. ), Diacyl ditellurides, bis (oxycarbonyl) ditellurides, bis (carbamoyl) ditellurides (specifically, for example, dibenzoyl ditelluride,
Bis (N-methyl-N-phenylcarbamoyl) ditelluride, bis (N, N-diphenylcarbamoyl) ditelluride and the like. ), (Te-b) a compound having a P = Te bond (e.g., phosphine tellurides (e.g., tributylphosphine telluride, tri-iso-butylphosphine telluride, tri-iso-propylphosphine telluride, n-butyldiene) -Iso-propylphosphine telluride)), tellurophosphonic acid amides (such as tris (dimethylamino) phosphane telluride, tris (diethylamino) phosphane telluride and the like), tellurophosphinic acid esters (such as , Diethyltellurophosphinic acid-O-ethyl ester (Et ₂
(EtO) P = Te), tellurophosphonic acid esters (e.g., ethyldiethoxyphosphane telluride), (Te-c) tellurocarboxylates (e.g., tellurobenzoic acid potassium salt, 2-methoxy) (Te-d) Te-organyltellurocarboxylates (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, ethane terrol, sodium ethane tellurate, etc.) ), (Te-g) telluroacetals (for example, , 1-bis (methyltelluro) butane, tritellurane, etc.), (Te-h) tellurosulfonates (eg, Te-ethylbenzenetellurosulfonate), (Te-i) a compound having a P-Te bond (eg, telluro) Phosphoric acid), Te-organyl esters (for example, specifically, tellurophosphoric acid-O, O-diethyl-Te-methyl ester, tellurophosphoric acid-O, O-dibutyl-Te-ethyl ester Etc.), (Te-j) Te-containing heterocycles (for example, telluradiazoles), (Te-k) tellurocarbonyl compounds (for example, telluroureas (for example, N, N'-dimethylethylenetellurorea) , N, N'-diethylethylenetellurorea, etc.)
Cyclic tellurourea compounds are preferred. ), Telluroamides (eg, dimethyltellurobenzamide, N, N-dipropyl-4-methoxytellurobenzamide, etc.), tellurohydrazides (eg, (N, N ′, N′-trimethyl) tellurobenzohydrazide, etc.), (Te -L) inorganic tellurium compounds (for example, tellurium sulfides, sodium telluride, potassium telluride,
And (Te-m) colloidal tellurium.

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 a chalcogen sensitizer in the present invention is not particularly limited as long as the effects of the present invention are exhibited. Preferably, after forming silver halide grains, organic fatty acid silver (described later) and 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 in addition to a noble metal sensitization method such as a gold compound, platinum, palladium or iridium compound or a reduction sensitization method, in addition 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.

Spectral sensitizing dyes are adsorbed on silver halide grains and contribute 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-band is 3.
It is preferably from 00 nm to 600 nm. In the application to X-ray medical light-sensitive materials utilizing a phosphor, the spectral sensitizing dye according to the present invention is adsorbed on silver halide emulsion grains,
When the reflection spectrum is measured, it is preferable that the J-band is formed in the same wavelength region as the blue light and the green light from the phosphor used for the intensifying screen. That is, the maximum absorption wavelength is preferably in the range of 300 nm to 600 nm, and more preferably, in the range of 330 to 570 nm. In the case of a blue phosphor, it is preferable to select and combine spectral sensitizing dyes such that a J-band having the maximum absorption in the range of 340 to 500 nm is formed, and more preferably 350 to 450 nm. Preferably 36
0 to 420 nm. In the case of a green phosphor, 52
It is preferable to select and combine spectral sensitizing dyes such that a J-band having the maximum absorption in the range of 0 to 555 nm is formed, and more preferably 530 to 553 nm.
And most preferably 540 to 550 nm.

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 composite merocyanine dye includes 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 the combination of sensitizing dyes is often used particularly for supersensitization. Along with the sensitizing dye, the emulsion may contain a dye which does not itself have a spectral sensitizing effect or a substance which does not substantially absorb visible light and exhibits supersensitization. For 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.

In the present invention, the amount of the spectral sensitizing dye added 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, and 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.

As a dispersant for the spectral sensitizing dye, a surfactant has conventionally been used. 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 a 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.

The photothermographic material of the present invention preferably contains a compound represented by the general formula 1. These compounds act as antifoggants and are effective in increasing the sensitivity of the photothermographic material of the present invention and minimizing fog when combined with the chemical sensitization by the chalcogen compound.

The compound represented by Formula 1 used in the present invention will be described in detail.

The halogen atoms represented by Hal ₁ and Hal ₂ may be the same or different and each independently represents a chlorine atom, a bromine atom, an iodine atom or a fluorine atom. Is the case.

Specific examples of the anion group represented by X include a halogen anion (chlorine anion, bromine anion, iodine anion and fluorine anion), a carboxylate anion,
Sulfonate anion, phosphate anion and the like can be mentioned, but a halogen anion is preferable, and a bromine anion is more preferable.

R ₁ represents a group having a carbonyl group as a partial structure, specifically, an acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms). And 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 2 carbon atoms).
12, for example, methoxycarbonyl, ethoxycarbonyl and the like. ), An aryloxycarbonyl group (preferably having 7 to 20 carbon atoms, more preferably having 7 to 16 carbon atoms, particularly preferably having 7 to 12 carbon atoms, and examples thereof include phenyloxycarbonyl).
Acylamino group (preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms)
And include, for example, acetylamino, benzoylamino and the like. ), An alkoxycarbonylamino group (preferably having 2 to 20 carbon atoms, more preferably having 2 to 1 carbon atoms)
6, particularly preferably having 2 to 12 carbon atoms, such as methoxycarbonylamino. ), An aryloxycarbonylamino group (preferably having 7 to 2 carbon atoms)
0, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonylamino. ), A carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 16 carbon atoms,
Particularly preferably, it has 1 to 12 carbon atoms, and examples thereof include carbamoyl, methylcarbamoyl, diethylcarbamoyl, and phenylcarbamoyl. ), A ureido group (preferably having 1 to 20 carbon atoms, more preferably 1 carbon atom)
To 16, particularly preferably 1 to 12 carbon atoms, for example, ureide, methylureide, phenylureide and the like. ). An acyl group is preferred, and an acetyl group is particularly preferred.

R ₂ and R ₃ represent a hydrogen atom or a substituent which can be substituted on a nitrogen atom. Specific examples of the group that can be substituted for a nitrogen atom include a halogen atom (a chlorine atom, a bromine atom, an iodine atom, a fluorine atom, and preferably a bromine atom), an alkyl group (preferably having 1 to 20 carbon atoms, More preferably, it has 1 to 12 carbon atoms, and particularly preferably 1 to 12 carbon atoms.
8, for example, methyl, trifluoromethyl, ethyl, iso-propyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl,
Cyclopentyl, cyclohexyl and the like can be mentioned. ), An alkenyl group (preferably having 2 to 20 carbon atoms, more preferably having 2 to 12 carbon atoms, and particularly preferably having 2 carbon atoms.
-8, for example, vinyl, allyl, 2-butenyl, 3
-Pentenyl and the like. ), Alkynyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, for example, propargyl,
Pentenyl and the like. ), An aryl group (preferably having 6 to 30 carbon atoms, more preferably having 6 to 20 carbon atoms,
Particularly preferably, it has 2 to 12 carbon atoms, and examples thereof include phenyl, p-methylphenyl, and naphthyl. ), An amino group (preferably having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, and particularly preferably 0 to 6 carbon atoms).
And examples thereof include amino, methylamino, dimethylamino, diethylamino, dibenzylamino and the like. ), An acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 1 carbon atoms).
2, 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, for example, methoxycarbonyl, ethoxycarbonyl and the like.), Aryloxycarbonyl A group (preferably having 7 to 20 carbon atoms, more preferably having 7 to 16 carbon atoms, particularly preferably having 7 to 12 carbon atoms, for example, phenyloxycarbonyl and the like), an acylamino group (preferably having 2 to 2 carbon atoms). 20, more preferably 2 carbon atoms
-16, particularly preferably 2-10 carbon atoms, such as acetylamino and benzoylamino. ), 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, for example, methoxycarbonylamino and the like), an aryloxycarbonyl group (Preferably 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonyl, etc.), a sulfonylamino group (preferably 1 to carbon atoms). 2
0, 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 having 0 to 20 carbon atoms, more preferably having 0 to 16 carbon atoms, and particularly preferably having 0 to 12 carbon atoms.
And include, for example, sulfamoyl, methylsulfamoyl, dimethylsulfamoyl and the like. ), A carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include carbamoyl, methylcarbamoyl, diethylcarbamoyl, and phenylcarbamoyl). An alkylsulfonyl group (preferably having 1 carbon atom)
20 to 20, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylsulfonyl and ethylsulfonyl. ), An arylsulfonyl 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, phenylsulfonyl and the like can be mentioned. ), A sulfinyl group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 16 carbon atoms, particularly preferably having 1 to 12 carbon atoms and including methanesulfinyl and benzenesulfinyl), and a ureido group (preferably Carbon number 1-2
It has 0, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and examples thereof include ureide, methylureide, and phenylureide. ), A silyl group (for example, trimethylsilyl group), a nitro group, a hydroxy group, a phosphate group, and a heterocyclic group (for example, triazolyl, imidazolyl, pyridyl, furyl, piperidyl, morpholinyl and the like). These groups may be further substituted. n is 1 or 2
And more preferably 2.

When the silver halide sensitized with a chalcogen compound is used in a photothermographic material, the compound represented by the general formula 1 becomes an effective antifoggant as described above. Specific examples of the compound represented by the general formula 1 are shown below. The present invention is not limited to these compounds.

[0136]

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[0137]

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[0138]

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Many of the above compounds of the present invention are known and can be purchased directly from reagent manufacturers such as Tokyo Chemical Industry. Further, it can be easily synthesized and produced according to the following literature. Representative document names are listed below. Japan Chemical Magazine 78, 1400, 1957, Ar
m. Khim. Zh. Vol. 30, p. 845, 1977, DE
No. 2018719, Dokl. Chem. 146, 851, 1962; Prakt. Chem.
<2> 129: 273, 1931; Gen. Ch
em. USSR 56 6 No. 1147 1986, Z
h. Obshch. Khim. 26, 3139, 195
Six years, Angew. Chem. 71, 126, 1959
Years, Seances Acad. Sci. 136 vol.14
71, 1903; Amer. Chem. Soc.
79, 4622, 1957, Bull. Soc. Ch
im. Fr. <3> Vol. 7, p. 73, 1892; Che
m. Soc. 2783, 1931; Prakt.
Chem. <2> 145: 257, 1936; C
hem. Soc. Dalton Trans. 821, 1980; Chem. Soc. Dalton T
rans. 15, 2261, 1993, Bull. C
hem. Soc. Jpn. 31, 347, 1958
Chem. Ber. 16: 559, 1883, Re
c. Trav. Chim. Pays-Bas. Volume 6 38
0 page 1887, Chem. Ber. 40, 4572, 1907, Zh. Org. Khim. 6, 2150, 1970, Synthesis 573, 1979,
SU968261, J.C. Amer. Chem. S
oc. 91, 1679, 1969; Org. Ch
em. 37, 2172, 1972; Chem. S
oc. 77, 799, 1900, Pol. J. Che
m. 69, No. 4, p. 605, 1995, Angew. Ch
em. Vol. 36, No. 21, p. 2342, 1997, Bull.
Chem. Soc. Jpn. 60, 4187, 1997
Year, Chem. Ber. 26, 425, 1893, L
iebigs Ann. Chem. 607: 109
957, Org. Synth. Coll. Vol. IV
489, 1963, An. Asoc. Quim An
gent. 37, 192, 1949; Org. C
hem. 28, 1100, 1963, Tetrah
drone Lett. 2, 117, 1969, Che
m. Heterocycl. Compd. 5, 844, 1969; Chem. Soc. Perkin T
rans. 1, 909, 1978; Org. Ch
em. 34, 3434, 1969, Synthesi
s6: 511, 1979, Tetrahedron3
8, 10977, 1976; Chem. Res.
Miniprint 7, page 1734, 1995; C
hem. Soc. P.2783, 1931, Justus
Liebigs Ann. Chem. 346, 217, 1906, Chem. Ber. 34, 2087, page 19
2001, Chem. Ber. 36, 987, 1981
Year, Collect. Czeuch. Chem. Com
mun. Vol. 53, No. 12, page 3166, 1988, Bull
l. Chem. Soc. Jpn. 60, 3 pages 1159, 1987, Synthesis 12, 987, 198
One year, Bull. Chem. Soc. Jpn. 64 volumes 3
No. 796, 1991, Justus Liebigs
Ann. Chem. 679, 133, 1961;
Org. Chem. USSR Vol. 3, No. 3, p. 449, 198
8 years, J. Chem. Soc. Chem. Commu
n. 16, 1127, 1985; Org. Che
m. USSR Vol. 28, No. 9, pp. 1543, 1992, Bull
l. Chem. Soc. Jpn. 60, No. 7, page 2667, 1987, Synth. Commun. 25, No. 21, p. 3497, 1995; Org. Chem. USS
R 28: 9.2, 1543, 1992, Bull.
Chem. Soc. Jpn. 44, 1141, 1971
Year, J. Amer. Chem. Soc. 19, 562, 1897.

The amount of the compound represented by the general formula 1 used in the present invention is not particularly limited, but may be from 10 ^-6 to 1 mol / Ag.
Mol is preferable, and particularly preferably 10 ^-4 to 10 ^-2 mol / Ag mol.

The compound represented by the general formula 1 used in the present invention can be added to a photosensitive layer or a non-photosensitive layer. Preferably, it is a photosensitive layer. Further, the compound represented by the general formula 1 of the present invention is preferably added after being dissolved in an organic solvent.

In the present invention, the organic silver salt is a reducible silver source, and a silver salt of an organic acid or a heteroorganic 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.) and hydroxy-substituted acids (eg, salicylic acid, benzoic acid, 3,
Silver complex of a reaction product with 5-dihydroxybenzoic acid, 5,5-thiodisalicylic acid); silver salts or complexes of thiones (for example, 3- (2-carboxyethyl) -4-hydroxymethyl-4- (Thiazoline-2-thione, and 3
-Carboxymethyl-4-thiazoline-2-thione)), imidazole, pyrazole, urazole, 1,
Complexes or salts of silver with a nitrogen acid selected from 2,4-thiazole and 1H-tetrazole, 3-amino-5-benzylthio-1,2,4-triazole and benzotriazole; saccharin, 5-chlorosalicylaldoxime And silver salts of mercaptides. Preferred silver sources are silver behenate, silver arachidate and silver stearate. The organic silver salt is preferably contained at a silver amount of 4 g / m ² or less. More preferably, it is 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 fatty acid silver to fatty acid ratio 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 Res
No. 17029, and 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 , 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) -1-methylethylidene) -1,3-oxazolidine-2-thione-4-one); 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 (eg, 6-chlorophthala) Dinone + sodium benzenesulfinate or 8-methylphthalazinone + p-tolyl Phosphate sodium); combinations of phthalazine + phthalic acid; phthalazine (including phthalazine adducts) with maleic anhydride, and phthalic acid, 2,3
Combination with at least one compound selected from naphthalenedicarboxylic acid or o-phenylene acid derivatives and anhydrides thereof (for example, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride); quinazolinedione , Benzoxazine, naloxazine derivatives; benzoxazine-2,4-diones (eg, 1,3-benzoxazine-2,4-dione); pyrimidines and asymmetric triazines (eg,
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.

The binder of the photosensitive layer and the dye-containing layer of the present invention is a polymer soluble or dispersible in an aqueous solvent (aqueous solvent). By using such a polymer, it is possible to coat a photosensitive layer using a water solvent containing 30% by weight or more of water as a coating solvent, which is advantageous in terms of environment and cost, and particularly in a high humidity atmosphere. The occurrence of fogging due to storage in the storage is suppressed.

The aqueous solvent in which the polymer of the present invention is soluble or dispersible means water or 70% by weight of water.
It is a mixture of the following water-miscible organic solvents. Examples of water-miscible organic solvents include, for example, methyl alcohol,
Examples thereof include alcohols such as ethyl alcohol and propyl alcohol, cellosolves such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve, ethyl acetate, and dimethylformamide.

A system in which the polymer is not thermodynamically dissolved but exists in a so-called dispersed state (latex)
In this case, the term "aqueous solvent" is used here.

As the polymer of the present invention, for example, acrylic resin, polyester resin, polyurethane resin, vinyl chloride resin, vinylidene chloride resin, rubber resin (for example, S
(BR resin and NBR resin), vinyl acetate resin, polyolefin resin, polyvinyl acetal resin and the like.

The polymer may be a homopolymer obtained by polymerizing a single monomer or a copolymer obtained by polymerizing two or more polymers. The polymer may be a linear or branched polymer. Further, the polymers may be crosslinked.

As the molecular weight of the polymer, the weight average molecular weight Mw is 1,000 to 1,000,000, preferably 3,000.
~ 500,000 is desirable. Those having a molecular weight of less than 1000 generally have low film strength after coating, and may cause inconveniences such as cracks in the photosensitive layer.

Specific examples of the polymer of the main binder of the photosensitive layer of the present invention include the following.

[0154] _{P-1 :-( MMA) 50 -} (EA) 45 -
(AA) ₅ - latex (Mw = 3 million _{in) P-2 :-( 2EHA) 30} - (MMA) 50 - (St) 15
- (MAA) ₅ - latex (Mw = 5 million _{in) P-3 :-( BR) 50} - (St) 47 - (AA) 3 - latex (Mw = 1 million in) P-4 :-( BR) _40- (DVB) _10- (St) _45-
(MAA) ₅ - latex (Mw = 5 million _{in) P-5 :-( VC) 70} - (MMA) 25 - (AA) 5 - latex (Mw = 1.5 million in) P-6 :-( VDC ) _60- (MMA) _30- (EA) _5-
(MAA) Latex of ₅ (Mw = 80,000) In the above, abbreviations represent structural units derived from the following monomers, and numerical values are wt%.

MMA: methyl methacrylate, EA: ethyl acrylate, AA: acrylic acid, 2EHA: 2-
Ethylhexyl acrylate, St: styrene, MA
A: methacrylic acid, BR: butadiene, DVB: divinylbenzene, VC: vinyl chloride, VDC: vinylidene chloride Also, such polymers are commercially available and the following can be used.

For example, as the acrylic resin, Sebian A
−4635, 46583, 4601 (all manufactured by Daicel Chemical Industries, Ltd.), Nipol LX811, 814, 8
As polyester resins such as 20, 821, 857 (all manufactured by Zeon Corporation), FINETEX ES
650, 611, 679, 675, 525, 801, 8
50 (all manufactured by Dainippon Ink and Chemicals, Inc.), WDsize
Examples of polyurethane resins such as WHS (manufactured by Eastman Chemical) include HYDRAN AP10, 20, 3
0, 40, 101H, HYDRAN HW301, 31
Examples of vinylidene chloride resins such as L.0, 350 (all manufactured by Dainippon Ink and Chemicals, Inc.) include L502, L513, L1
Examples of vinyl chloride resins such as 23c, L106c, L111 and L114 (all manufactured by Asahi Kasei Corporation) include G35
Examples of polyolefin resins such as 1, G576 (all manufactured by Nippon Zeon Co., Ltd.) include Chemipearl S-120, S-3
00, SA-100, A-100, V-100, V-2
00 and V-300 (all manufactured by Mitsui Petrochemical Co., Ltd.).

In the binder of the present invention, these polymers may be used alone or as a blend of two or more.

In the photosensitive layer and the dye layer of the present invention, the above polymer is used as a main binder. The main binder as used herein means “70% by weight of all binders in the photosensitive layer or the dye layer.
The above is the state in which the above-mentioned polymer occupies. It is more preferably at least 80 wt%, and it is also preferable to use only these polymers. When two or more types are used, the total amount is used.

In the present invention, the photosensitive layer and the dye layer are formed using a coating solution. The solvent for the coating solution is a water solvent containing 30% by weight or more of water. A water-miscible organic solvent may be contained. Examples of the preferred water solvent include water (100), a water / methanol system, for example, water (90) / methanol (10), water (7).
0) / methanol (30), water (60) / methanol (40), water (40) / methanol (60), water / methanol / isopropyl alcohol system, for example, water (80)
/ Methanol (10) / isopropyl alcohol (1
0), water / dimethylformamide system such as water (95)
/ Dimethylformamide (5), water / ethyl acetate system, for example, water (96) / ethyl acetate (4), water / methanol /
A butyl cellosolve type, for example, water (80) / methanol (10) / butyl cellosolve (10) is mentioned (however, a numerical value shows wt%). Above all, 70 water
It is preferable that the solvent contains not less than wt%.

The amount of the binder in the photosensitive layer of the invention is 5: 5 by weight in terms of the ratio of the binder to the photosensitive silver halide.
It is preferably 1-1500: 1, more preferably 10: 1-800: 1. The ratio of the binder to the non-photosensitive silver salt is preferably 15: 1 to 1: 2, more preferably 8: 1 to 1: 1.

In the present invention, when a dye layer is separately provided,
The binder of the dye layer is the amount of 0.01g~10g / m ^2, preferably 0.1-5 g / m ^2.

The same binder can be applied to the protective layer provided on the outermost surface side of the light-sensitive material, but gelatin is preferred as the binder for the protective layer. By using an aqueous coating solution, the dye which is bleached by light and heat according to the present invention is stably present as a fine particle dispersion in the layer, and does not cause unnecessary reaction before exposure and does not cause bleaching of the dye. The halogen compound does not adversely affect the performance of the photothermographic material without causing an unnecessary reaction. The amount of the binder in the protective layer is also 0.01 g to 10 g / m ² , preferably 0.1 g / m ² .
1 to 5 g / m ² .

In the present invention, the protective layer on both sides preferably contains a matting agent. In order to improve the repeatability of the dimensions of the present invention, a polymer matting agent or an inorganic matting agent is added to all binders on the emulsion layer side. On the other hand, the weight ratio is 0.5 to
It is preferable to contain 10%.

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 variation coefficient 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, but is preferably used in order to achieve the object of the present invention. Is a constituent layer other than the photosensitive layer, and is more preferably the outermost layer as viewed from the support.

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 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. In the photothermographic material of the present invention, for example, a surfactant, an antioxidant, a stabilizer, a plasticizer, an ultraviolet absorber,
A coating aid or the like may be used.

The layer having a dye which is bleached by heat or light after exposure according to the present invention may be used for the purpose of blocking crossover light when the photosensitive material is sandwiched between fluorescent intensifying screens and exposed from both sides. More preferably, it is contained in a layer closer to the support. The dye used in the crossover light-blocking layer of the present invention absorbs light transmitted through the photothermographic layer at the time of image exposure, blocks the crossover light by absorbing the dye in the blocking layer, and then thermally decomposes. Alternatively, it is decomposed and decolored by overall exposure after heat development.

There are no particular restrictions on the method of coating the necessary layers on the light-sensitive material of the present invention, such as a light-sensitive layer, a protective layer, and a back coat layer.
Methods such as dip coating, bar coating, curtain coating, and hopper coating can be used. Further, two or more of these layers may be applied simultaneously.

As the support on which the above-mentioned photosensitive layer, crossover cut layer, protective layer and the like in the photothermographic material of the present invention are coated, a plastic film (for example, a cellulose acetate film, a polyester film, a polyethylene terephthalate film, a polyethylene terephthalate film) A naphthalate film, a polyamide film, a polyimide film, a cellulose triacetate film, a polycarbonate film, or the like) is preferable. In the present invention, a biaxially stretched polyethylene terephthalate film and a polyethylene naphthalate film are particularly preferable. The thickness of the support is about 50 to 300 μm, preferably 70 to 180 μm.

The photothermographic material of the present invention is stable at room temperature, but is developed by heating to 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.

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

When the heat-developable photographic material of the present invention is applied to medical X-ray radiography, for example, a fluorescent intensifier mainly composed of a phosphor that generates near-ultraviolet light or visible light upon exposure to penetrating radiation. An impression paper 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. In the present invention, as a preferred phosphor used in the fluorescent intensifying screen,
The following are mentioned.

Tungstate phosphors (CaWO ₄ ,
MgWO ₄ , CaWO ₄ : Pb, etc.), terbium-activated rare earth oxysulfide-based phosphor [Y ₂ O ₂ S: Tb, Gd ₂ O ₂ S: T
b, La ₂ O ₂ S: Tb, (Y, Gd) ₂ O ₂ S: Tb,
(Y, Gd) O ₂ S: Tb, Tm, etc.], terbium-activated rare earth phosphate-based phosphor (YPO ₄ : Tb, GdPO ₄ : T
b, LaPO ₄ : Tb, etc.), terbium-activated rare earth oxyhalide phosphor (LaOBr: Tb, LaOB)
r: Tb, Tm, LaOCl: Tb, LaOCl: T
b, Tm, LaOBr: Tb, GdOBr: Tb, Gd
OCL: Tb, etc.), thulium-activated rare earth oxyhalide-based phosphors (LaOBr: Tm, LaOCl: Tm)
Etc.), barium sulfate-based phosphor [BaSO ₄ : Pb, Ba
SO ₄ : Eu ²⁺ , (Ba, Sr) SO ₄ : Eu ²⁺ etc.), 2
-Valent europium-activated alkaline earth metal phosphate-based phosphor [(Ba ₂ PO ₄ ) ₂ : Eu ²⁺ , (Ba ₂ PO ₄ ) ₂ : Eu ²⁺
Etc.], divalent europium-activated alkaline earth metal fluorohalide-based phosphor [BaFCl: Eu ²⁺ , BaFB
r: Eu ²⁺ , BaFCl: Eu ²⁺ , Tb, BaFBr:
Eu ²⁺ , Tb, BaF ₂ .BaCl.KCl: Eu ²⁺ ,
(Ba, Mg) F ₂ .BaCl.KCl: Eu ²⁺ etc.],
Iodide phosphors (CsI: Na, CsI: Tl, Na
I, KI: Tl, etc.), sulfide-based phosphors [ZnS: Ag
(Zn, Cd) S: Ag, (Zn, Cd) S: Cu,
(Zn, Cd) S: Cu, Al, etc.], hafnium phosphate-based phosphor (HfP ₂ O ₇ : Cu, etc.), provided that the phosphor used in the present invention is not limited to these, Any phosphor that emits light in the visible or near ultraviolet region can be used.

The fluorescent intensifying screen used in the present invention is preferably filled with a phosphor having a gradient particle size structure. In particular, it is preferable to apply phosphor particles having a large particle diameter to the surface protective layer side and to apply phosphor particles having a small particle diameter to the support side. Those with a particle size of 10 to 30 μm
Is preferable.

Hereinafter, a preferred method for producing a fluorescent intensifying screen will be described.

Step of Forming Phosphor Sheet Composed of Binder and Phosphor The phosphor sheet is placed on a support, and the phosphor sheet is compressed at a temperature equal to or higher than the softening temperature or the melting point of the binder. It is preferable to manufacture it in the step of bonding to a support.

The phosphor sheet serving as the phosphor layer of the fluorescent intensifying screen is prepared by applying a coating solution in which a phosphor is uniformly dispersed in a binder solution onto a temporary support for forming a phosphor sheet, and drying. Then, it can be manufactured by peeling off from the temporary support. That is, first, a binder and phosphor particles are added to an appropriate organic solvent, and the mixture is stirred and mixed to prepare a coating solution in which the phosphor is uniformly dispersed in the binder.

The binder has a softening temperature or melting point of 30.
A thermoplastic elastomer having a temperature of from 150C to 150C is used alone or together with another binder. Since the thermoplastic elastomer has elasticity at normal temperature and becomes fluid when heated, it is possible to prevent the phosphor from being damaged by the pressure at the time of compression. Examples of the thermoplastic elastomer include polystyrene, polyolefin, polyurethane, polyester, polyamide, polybutadiene, ethylene vinyl acetate, polyvinyl chloride, natural rubber, fluorine rubber, polyisoprene, chlorinated polyethylene, styrene-butadiene rubber, and silicon rubber. At least one type of thermoplastic elastomer selected from the group is exemplified. The mixing ratio of the thermoplastic resin in the binder is 10% by weight or more and 100% by weight or more.
The binder may be made up of as much thermoplastic elastomer as possible, in particular 100% by weight.

Examples of the solvent for preparing the coating solution include lower alcohols such as methanol, ethanol, n-propanol and n-butanol, hydrocarbons containing chlorine atoms such as methylene chloride and ethylene chloride, acetone, methyl ethyl ketone and methyl isobutyl ketone. Ketones, esters of lower fatty acids with lower alcohols such as methyl acetate, ethyl acetate and butyl acetate, ethers such as dioxane, ethylene glycol monoethyl ester and ethylene glycol monomethyl ester, and mixtures thereof.

The mixing ratio between the binder and the phosphor in the coating solution varies depending on the characteristics of the intended fluorescent intensifying screen, the type of the phosphor, and the like. Generally, the mixing ratio between the binder and the phosphor is 1: 1.
It is selected from the range of 1 to 1: 100 (weight ratio), and particularly preferably selected from the range of 1: 8 to 1:40 (weight ratio).

In the coating solution, a dispersant for improving the dispersibility of the phosphor in the coating solution or a bonding force between the binder and the phosphor in the formed phosphor layer are improved. Various additives such as a plasticizer may be mixed.

Examples of dispersants include phthalic acid, stearic acid, caproic acid, lipophilic surfactants and the like.

Examples of the plasticizer include phosphoric esters such as triphenyl phosphate, tricresyl phosphate and diphenyl phosphate; phthalic esters such as diethyl phthalate and dimethoxyethyl phthalate; ethyl phthalethyl glycolate;
Glycolic acid esters such as butyl phthalate butyl glycol and the like, polyesters of triethylene glycol and adipic acid, polyesters of polyethylene glycol such as polyester of diethylene glycol and succinic acid, and polyesters of aliphatic dibasic acids can be exemplified.

The coating solution containing the phosphor and the binder prepared as described above is uniformly applied to the surface of the temporary support for sheet formation to form a coating film of the coating solution.

As the coating means, for example, a doctor blade, a roll coater, a knife coater or the like can be used.

As the temporary support, for example, those made of various materials such as glass, wool, cotton, paper, and metal can be used. What can be processed into is preferred. From this point, for example, cellulose acetate film, polyester film, polyethylene terephthalate film, polyamide film, polyimide film, triacetate film, plastic film such as polycarbonate film, metal sheet such as aluminum foil and aluminum alloy foil, general paper and photographic base paper Base paper for printing, such as coated paper or art paper, baryta paper, resin coated paper, paper sized with polysaccharide as described in Belgian Patent No. 784,615, titanium dioxide, etc. Pigmented paper containing pigments, and processed paper such as paper sized with polyvinyl alcohol are particularly preferred.

After the coating solution for forming a phosphor layer is applied to the temporary support and dried, the coating solution is peeled off from the temporary support to form a phosphor sheet to be a phosphor layer of a fluorescent intensifying screen. Therefore, it is preferable that a release agent is applied to the surface of the temporary support in advance so that the formed phosphor sheet is easily peeled from the temporary support.

A description will now be given. A sheet for setting the phosphor formed as described above is prepared. This support can be arbitrarily selected from the materials listed for the temporary support.

The fluorescent intensifying screen is provided with an undercoat layer for imparting adhesiveness by applying a polymer substance such as gelatin on the surface of the support in order to strengthen the bond between the support and the phosphor layer.
In order to improve image quality (sharpness, granularity), a light reflecting layer made of a light reflecting material such as titanium dioxide or a light absorbing layer made of a light absorbing material such as carbon black may be provided.

The fluorescent intensifying screen used in the present invention can also be provided with these various layers, and the structure thereof can be arbitrarily selected according to the desired purpose and use of the fluorescent intensifying screen.

The phosphor sheet obtained as described above is placed on a support, and the phosphor sheet is bonded to the support while being compressed at a temperature not lower than the softening temperature or the melting point of the binder.

In this way, by using the method of pressing the sheet without fixing it to the phosphor sheet support in advance, the sheet can be spread thinly and not only can prevent the phosphor from being damaged but also fix the sheet. It is possible to obtain a high phosphor filling rate even at the same pressure as compared with the case where the pressure is increased.

Examples of the compression device used for the compression process include generally known devices such as a calender roll and a hot press. For example, the compression treatment using a calender roll is performed by placing the phosphor sheet obtained on a support and passing the phosphor sheet at a constant speed between rollers heated to a temperature higher than the softening temperature or melting point of the binder. The pressure during compression is 50 kg / cm ²
It is preferable that this is the case.

Usually, the fluorescent intensifying screen is provided with a transparent protective film for physically and chemically protecting the phosphor layer on the surface of the phosphor layer opposite to the side in contact with the support described above. . Such a transparent protective film is preferably provided also for the fluorescent intensifying screen of the present invention. The thickness of the protective film is generally in the range of 0.1 to 20 μm.

The transparent protective layer is made of a cellulose derivative such as cellulose acetate or nitrocellulose, or a synthetic polymer such as polymethyl methacrylate, polyethylene terephthalate, polyvinyl butyral, polyvinyl formal, polycarbonate, polyvinyl acetate, or vinyl chloride / vinyl acetate copolymer. Is dissolved in an appropriate solvent, and a solution prepared by coating the solution on the surface of the phosphor layer can be formed.

Alternatively, a plastic sheet made of polyethylene terephthalate, polyethylene naphthalate, polyethylene, polyvinylidene chloride, polyamide, or the like, or a sheet for forming a protective film such as a transparent glass plate is separately prepared and is appropriately bonded to the surface of the phosphor layer. It can be formed by a method such as bonding using an agent.

In the present invention, as the protective layer used in the fluorescent intensifying screen, a film formed by a coating film containing a fluorine-based resin soluble in an organic solvent is particularly preferable. The fluorine-based resin refers to a polymer of an olefin containing fluorine (fluoroolefin) or a copolymer containing an olefin containing fluorine as a copolymer component. The film formed by the coating film of the fluorine-based resin may be cross-linked. The advantage of a protective film made of a fluorine-based resin is that dirt such as a plasticizer that comes out of a film or the like when coming into contact with another material or an X-ray film hardly penetrates into the protective film, so that the dirt can be easily removed by wiping or the like. There is.

When a fluorine-based resin soluble in an organic solvent was used as the material for forming the protective film, this resin was prepared by dissolving the resin in an appropriate solvent. That is, the protective film is formed by uniformly applying a coating liquid for a protective film forming material containing a fluorine-based resin soluble in an organic solvent to the surface of the phosphor layer using a doctor blade or the like, followed by drying. The formation of this protective film may be performed simultaneously with the formation of the phosphor by simultaneous multilayer coating.

The fluorine-based resin is a polymer of a fluorine-containing olefin (fluoroolefin) or a copolymer containing a fluorine-containing olefin as a copolymer component, such as polytetrafluoroethylene, polychlorotrifluoroethylene, or polyfluorene. Examples include ethylene fluoride, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, and fluoroolein-vinyl ether copolymer.

The fluorine-based resin is generally insoluble in an organic solvent, but a copolymer containing a fluoroolefin as a copolymer component becomes soluble in an organic solvent by a structural unit other than the fluoroolefin to be copolymerized. A protective layer can be easily formed by applying a solution prepared by dissolving in a suitable solvent on the phosphor layer and drying. Examples of such a copolymer include a fluoroolefin-vinyl ether copolymer. Also, polytetrafluoroethylene and its modified products are soluble in a suitable fluorine-based organic solvent such as a perfluoro solvent, and thus are protected by coating in the same manner as the copolymer containing the above-mentioned fluoroolefin as a copolymer component. A film can be formed.

The protective film may contain a resin other than the fluorine-based resin, and may contain a cross-linking agent, a hardening agent, an anti-yellowing agent and the like. However, in order to sufficiently achieve the above object, the content of the fluorine-based resin in the protective film must be 30% by weight.
Or more, more preferably 50% by weight.
The content is most preferably 70% by weight or more.

Examples of the resin other than the fluorine-based resin contained in the protective film include polyurethane resin, polyacryl resin, cellulose derivative, polymethyl methacrylate, polyester, epoxy resin and the like.

The protective film of the fluorescent intensifying screen used in the present invention may be formed from a coating film containing either one or both of a polysiloxane skeleton-containing oligomer and a perfluoroalkyl group-containing oligomer.

The polysiloxane skeleton-containing oligomer has, for example, a dimethylpolysiloxane skeleton.
Preferably, it has at least one functional group, for example, a hydroxyl group, and has a molecular weight of 500 to 100,000.
Is preferably within the range. Especially when the molecular weight is 1000
It is preferably in the range of 100,000, and more preferably in the range of 3,000 to 10,000. Further, the oligomer containing a perfluoroalkyl group, such as a tetrafluoroethylene group, is preferably one containing at least one functional group, for example, a hydroxyl group in the molecule,
The molecular weight is preferably in the range of 500 to 100,000. In particular, the molecular weight is preferably in the range of 1,000 to 100,000.

If the oligomer containing a functional group is used, a crosslinking reaction occurs between the oligomer and the resin for forming the protective layer at the time of forming the protective film, and the oligomer is incorporated into the molecular structure of the resin for forming the film. The oligomer is not removed from the protective film by long-term repeated use of the fluorescent intensifying screen or the operation of cleaning the surface of the protective film. Is advantageous. The oligomer is preferably contained in the protective film in an amount of 0.01 to 10% by weight, particularly preferably 0.1 to 2% by weight.

The protective layer may contain a perfluoroolefin resin powder or a silicon resin powder. As the perfluoroolefin resin powder or the silicon resin powder, those having an average particle diameter in the range of 0.1 to 10 μm are preferable, and particularly preferably the average particle diameter is 0.3 to 5 μm.
m. These perfluoroolefin resin powder or silicon resin powder is preferably contained in the protective film in an amount of 0.5 to 30% by weight, more preferably 2 to 20% by weight, based on the weight of the protective film. Preferably, it is most preferably in an amount of from 5 to 15% by weight.

[0211] The protective film of the fluorescent intensifying screen is preferably a transparent synthetic resin layer having a thickness of 5 µm or less formed on the phosphor layer. By using such a thin protective layer, the distance from the phosphor of the fluorescent intensifying screen to the silver halide emulsion is reduced, which contributes to the improvement of the sharpness of the obtained X-ray image.

In the present invention, the filling rate of the phosphor is determined by peeling off the protective layer of the fluorescent intensifying screen, eluting the phosphor layer with methyl ethyl ketone, filtering, drying and drying using an electric furnace.
When the weight of the phosphor obtained by baking at 1 ° C. for 1 hour to remove the resin on the surface is Og, the thickness of the phosphor layer is Pcm, the screen area used for elution is Qcm ² , and the phosphor density is Rg / cm ³ , the phosphor is filled. Rate = [O ÷ (P × Q × R)] × 100.

In the present invention, the intrinsic filtration is equivalent to 2.2 mm of aluminum, and the X-ray energy in the X-ray generator is at least 45% with respect to the X-ray of 80 kVp, more preferably 5%.
It is preferable to use a fluorescent intensifying screen showing an absorption amount of 0% or more. The X-ray absorption of the fluorescent intensifying screen can be measured by the following method.

X-rays generated from a tungsten target tube operated at 80 kVp with a three-phase
mm through the aluminum plate and reach the fluorescent screen of the sample fixed at a position 200 cm from the tungsten anode of the target tube. Then, the amount of X-rays transmitted through the fluorescent screen is measured by the fluorescent screen. 50cm from the phosphor layer
Measurement is performed at a later position using an ionizing dosimeter to determine the amount of X-ray absorption. Note that, as a reference, the X-ray dose at the above-described measurement position measured without passing through the fluorescent intensifying screen can be used.

It is preferable that the thickness of the phosphor is 135 to 200 μm, and the filling rate of the phosphor at this time is 68% or more.

With the fluorescent intensifying screen obtained in this way, the fluorescent screen is sandwiched from both sides so as to be in close contact with the photosensitive surface of the photothermographic material having an emulsion surface on both sides of the support to constitute an X-ray image forming unit. Then, this is exposed to X-rays transmitted through the subject using the X-ray generator as a light source, and a radiation image can be obtained. Examples of the X-ray generator include an X-ray imaging apparatus such as a penetrometer type B (manufactured by Konica Medical Co., Ltd.). Usually, a tube voltage of 50 to 200 kVp and a tube current of 50 to 4 are used.
X-ray irradiation is performed under conditions such as 00 mA and irradiation time of 5 to 100 msec.

Thereafter, an X-ray image can be obtained by performing heat development processing at a high temperature as described later using an automatic developing machine having a heat drum and a metal back roll.

[0218]

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 (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 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 and (98/2) potassium bromide, potassium iodide and iridium chloride in a molar ratio of 1 × 1 per mole of silver were used.
0 ^-4 mol aqueous solution containing 370 ml, was added over 10 minutes by the controlled double jet method while maintaining the pAg 7.7. Thereafter, 4-hydroxy-6-methyl-1,
0.3 g of 3,3a, 7-tetrazaindene was added and Na was added.
Adjust the pH to 5 with OH and average particle size 0.06μ
m, coefficient of variation of particle size 12%, [100] face ratio 8
7% of cubic silver iodobromide grains 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. This photosensitive silver halide emulsion was dissolved at 55 ° C., 1.0 × 10 ⁻⁴ mol / mol Ag of sodium thiosulfate was added, the mixture was stirred for 10 minutes, and then the selenium compound triphenylphosphine selenide was added to 1.0 × 10 ⁻⁴ mol / mol Ag. Add 10 ^-5 mol / mol Ag and add 20
The solution was quenched to ℃ to terminate the chemical sensitization to prepare a photosensitive silver halide emulsion a.

<Preparation of Powdered Organic Silver Salt A> In 4720 ml of pure water, 111.4 g of behenic acid and 83.8 of arachidic acid were used.
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.

When the temperature of the above-mentioned organic acid sodium acid 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 (MEK)
The mixture was dissolved in 1457 g, and 500 g of powdered organic silver salt A was gradually added to the mixture while stirring with a dissolver-type homogenizer, followed by thorough mixing. Then, add 1mmZr beads (Toray)
Dispersion was performed at a peripheral speed of 13 m and a residence time in the mill of 0.5 minute with a media type disperser (manufactured by Gettzmann) filled with 0% 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. with stirring, and the compound (1-1) of the compound of the formula (1-1) was used as an antifoggant. ) (10% methanol solution) was added, and the mixture was stirred for 1 hour. Further, 889 μl of calcium bromide (10% methanol solution) was added, and 3
Stirred for 0 minutes. Next, the sensitizing dye solution was added to 1.416 m
After adding 667 μl of the stabilizer solution and 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 (Butvar B-79, Monsanto)
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 (1,1′-bis (2-hydroxy-3,5-dimethylphenyl) -2-methylpropane) 3.00 g phthalazine 305 mg tetrachlorophthalic acid 102 mg 4-methylphthalic acid 137 mg After stirring for 1. minute, antifoggant solution 5.47 ml Desmodur N3300 (Mobay, Inc., aliphatic isocyanate) 1.60 ml of 10% MEK solution was sequentially added and stirred to obtain photosensitive layer coating solution 1.

[0230]

Embedded image

<< Preparation of Double-sided Photosensitive Coating Sample >> A crossover light blocking layer was coated on both sides of the support in order from the side closer to the support according to the following formulation, and then the photosensitive layer coating solution 1 was used. A photosensitive layer and a protective layer were successively formed according to the following formulation. However, the coated silver amount of the photosensitive layer was 1.5
g / m ² , and drying was performed at 75 ° C. for 5 minutes each. Thus, the coating sample 1 shown in Table 1 was produced.

<Crossover light blocking layer (COC-
1)> A crossover light blocking layer was provided below the photosensitive layer on both sides of the 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 <Surface protective layer solution 1> The surface protective layer solution 1 was coated so as to have the coating amount shown below. Coated on 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 monodisperse silica 70 mg / m ² Developer (same as above) 0.1 g / m ² or Further, coating samples 2 to 5 were prepared as follows.

<Preparation of Photosensitive Silver Halide Emulsion b> 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, potassium bromide and potassium iodide in a molar ratio of (98/2) were equimolar to silver nitrate, and iridium chloride was converted to silver 1
370 ml of an aqueous solution containing 1 × 10 ^-4 mol per mol was added to p
Ag was added over 10 minutes by a controlled double jet method while keeping the Ag at 7.7. Then 4-hydroxy-
6-methyl-1,3,3a, 7-tetrazaindene
After adding 3 g and adjusting the pH to 5 with NaOH, the average particle size was 0.06 μm, the variation coefficient of the particle size was 12%, and [1
00] Cubic silver iodobromide grains having an area ratio of 87% were obtained. This emulsion was subjected to coagulation sedimentation using a gelatin coagulant and desalting treatment, and then 0.1 g of phenoxyethanol was added thereto.
Ag was adjusted to 7.5 to obtain a photosensitive silver halide emulsion. The photosensitive silver halide emulsion was dissolved at 55 ° C., and the sensitizing dye (A) was added at 3.5 × 10 ⁻⁴ mol / molA.
g, sensitizing dye (B) at 3.5 × 10 ⁻⁴ mol / molA
g was added and stirred for 20 minutes. Thereafter, 1.0 × 10 ⁻⁴ mol / mol Ag of sodium thiosulfate was added, and chloroauric acid 3.4.
× 10 ⁻⁶ mol / molAg and 2.6 × 10 ⁻⁴ mol / molAg of ammonium thiocyanate were added and stirred for 10 minutes, and then a selenium compound (triphenylphosphine selenide) was added as a chalcogen compound to 1.0 × 10 ⁶ mol / molAg. ^-Five
mol / mol Ag was added, and the mixture was quenched to 20 ° C. to terminate the chemical sensitization, thereby preparing a photosensitive silver halide emulsion b.

<Preparation of Organic Acid Silver Crystalline Dispersion> 40 g of behenic acid, 7.3 g of stearic silver and 500 ml of water were stirred at 90 ° C. for 15 minutes, 187 ml of 1N NaOH was added over 15 minutes, and 1N NaOH was added. A nitric acid aqueous solution (61 ml) was added, and the temperature was lowered to 50 ° C. Next, 1N silver nitrate aqueous solution 124
ml was added over 2 minutes and stirred for 30 minutes. Thereafter, the solid content was separated by suction filtration, and the solid content was washed with water until the conductivity of the filtrate reached 30 μS / cm. The solid content thus obtained was handled as a wet cake without being dried, and a wet cake having a dry solid content of 34.8 g was added to 12 g of polyvinyl alcohol and 150 g of water.
ml was added and mixed well to form a slurry. Prepare 840 g of zirconia beads having an average diameter of 0.5 mm, put them in a vessel together with the slurry, disperse them in a dispersing machine (1 / 4G sand grinder mill: manufactured by IMEX Co., Ltd.) for 5 hours, and observe the average shortness by electron microscopy. 0.04μm in diameter,
The preparation of a microcrystalline dispersion of silver organic acid, which is needle-like particles having an average major axis of 0.8 μm and a projected area variation coefficient of 30%, was completed.

<Preparation of Material Solid Fine Particle Dispersion> Tetrachlorophthalic acid, 4-methylphthalic acid, 1,1-bis (2
-Hydroxy-3,5-dimethylphenyl) -3,5
Solid fine particle dispersions were prepared for 5-trimethylhexane, phthalazine, and tribromomethylphenylsulfone.

With respect to tetrachlorophthalic acid, 0.81 g of hydroxypropylmethylcellulose and 94.2 ml of water were used.
Was added, and the mixture was stirred well and left as a slurry for 10 hours. Thereafter, 100 ml of zirconia beads having an average diameter of 0.5 mm was prepared, placed in a vessel together with the slurry, and dispersed for 5 hours using the same dispersing machine as used in the preparation of the organic acid silver salt microcrystal dispersion, to obtain tetrachloromethane. A solid fine particle dispersion of phthalic acid was obtained. The particle size is 70μ% 1.0μ
m or less. For other materials, the amount of the dispersant used and the dispersion time were changed to obtain a desired average particle size, and solid fine particle dispersions were obtained for each material.

<Preparation of Coating Solution for Photosensitive Layer> The silver halide microcrystal dispersion (corresponding to 1 mol of silver) prepared above was prepared by adding a photosensitive silver halide emulsion b to 10 mol% of silver halide (based on organic acid). Silver) and the following polymer latex (Polymer P-
1) and a material were added to obtain a photosensitive layer coating solution 2. The average particle size of the polymer latex was about 0.1 μm.

Polymer latex (Polymer P-1) 430 g Tetrachlorophthalic acid 5 g 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane 98 g Phthalazine 9.2 g Tribromo 12 g of methylphenyl sulfone 7 g of 4-methylphthalic acid <Preparation of emulsion surface protective layer solution 2> 0.26 g of surfactant A and 0.2 g of surfactant B were added to 10 g of inert gelatin.
09 g, silica fine particles (average particle size 2.5 μm)
0.9 g, 1,2-bis {(vinylsulfonyl) acetamido} ethane, 0.3 g, and water, 64 g, were added to prepare a surface protective layer solution 2.

Surfactant A: potassium perfluorooctylsulfonylpropylaminoacetate Surfactant B: sodium tridecylbenzenesulfonate <Crossover light blocking layer (COC-2 to 5)> Merocyanine dye as follows: Photosensitive halogen-containing compounds,
N, N-dimethyl-p- (nitrophenylazo) aniline, and 2,3,4,5,6,2 ′, 3 ′, 4 ′, 5 ′,
The composition containing 6'-decafluorobenzopinacol was made into an aqueous solid fine particle dispersion by the same method as described above, and a crossover light-shielding layer was prepared. And dried as a crossover light blocking layer.

(COC-2) Gelatin 2 g / m ² Merocyanine dye (29) 30 mg / m ² Photosensitive halogen-containing compound 6 60 mg / m ² (COC-3) Gelatin 2 g / m ² Merocyanine dye (29) 30 mg / m ² Photosensitive halogen-containing compound 19 60 mg / m ² (COC-4) Gelatin 1 g / m ² N, N-dimethyl-p- (nitrophenylazo) aniline 10 mg / m ² p-Toluenesulfonic acid 300 mg / m ² 2, 3,4,5,6,2 ′, 3 ′, 4 ′, 5 ′, 6′-decafluorobenzopinacol 200 mg / m ² (COC-5) polysulfonamide 1 g / m ² N, N-dimethyl-p- (nitrophenylazo) aniline 20 mg / m ² toluenesulfonic acid ^{300mg / m 2 2,3,4,5,6,2 ', 3} ', 4 ', 5', 6 '- Dekafu B benzopinacol 400 mg / m ² polysulfonamide: those described in JP-A-53-145629. Water-soluble polymer having the following repeating unit

[0243]

Embedded image

<< Preparation of Double-sided Photosensitive Coating Samples 2-5 >> On the crossover light blocking layers COC-2 to COC-5, the photosensitive layer coating solution 2 and the surface protective layer solution 2 were coated in this order. 1.5 g / m ² , protective layer gelatin 2.3 g / m ²
m ² , and coating samples 2 to 5 shown in Table 1 were prepared.

(Preparation of Photosensitive Layer Coating Solution 3) Photosensitive layer was prepared except that compound (1-1) of general formula 1 of the present invention was added as an antifoggant in an amount of 3.6 × 10 ⁻³ mol / mol Ag at the beginning of coating solution preparation. Photosensitive layer coating solution 3 was prepared in the same manner as for layer coating solution 2.

(Preparation of Double-sided Photosensitive Coating Sample 6) The crossover light blocking layer COC-2, photosensitive layer coating solution 3, and protective layer coating solution 2 were arranged on both sides of the support in this order from the side closest to the support. The coated sample was coated and dried so that the coated silver amount of the photosensitive layer was 1.5 g / m ² and the gelatin amount of the protective layer was 2.3 g / m ^2, to thereby prepare a coated sample 6 shown in Table 1.

[0247]

[Table 1]

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

Separately, 90 g of a soft acrylic resin solid 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.

250 μm thickness kneaded with titanium dioxide
Polyethylene terephthalate base (support) was placed horizontally on a glass plate, and the coating solution for forming an undercoat layer was uniformly coated on the support using a doctor blade.
The coating film was dried by gradually raising the temperature from 100 ° C. to 100 ° C. to form an undercoat layer on the support. The thickness of the coating film is 15μ
m.

The above-mentioned coating solution for forming a phosphor layer was uniformly coated thereon 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 78.4 Pa and a temperature of 80 ° C. After this compression, a transparent protective film having a thickness of 3 μm was formed by the method described in Example 1 of JP-A-6-75097, and a fluorescent intensifying screen 1 was produced.

<< Exposure and Development Treatment >> Coating Samples 1 to 6
Was cut into 25 cm × 30 cm, and the fluorescent screen was sandwiched from both sides of the fluorescent intensifying screen 1 so that the fluorescent screen was in close contact with the coated sample. The tube voltage was 100 kVp and the tube current was 200 mA through a penetrometer B (manufactured by Konica Medical Co., Ltd.). , Irradiation time 50ms
X-ray irradiation was performed under the conditions of ec.

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. At that time, exposure and development were performed at 23 ° C and 50% R.
We went in a room conditioned to H. Samples 1 to 3 and 6 were exposed to light for 5 seconds from a distance of 10 cm with a 1 kW mercury lamp after the heat development treatment to decolorize the crossover cut dye.

The obtained image was evaluated by 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, and are shown in Table 2 as relative values with the sensitivity of the coated sample 1 being 100. Table 2 shows the results.

<< Evaluation of Raw Preservability >> Each of the coated samples 1 to 6 was cut into two pieces each having a size of 25 cm × 30 cm.
° C, RH55% for 3 days, the other one at 55 ° C, 55RH
% 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 equation.
Shown in

ΔDmin = Dmin (55 ° C., 55 RH
% For 3 days) -Dmin (3 days at 25 ° C. and 55 RH%) << Evaluation of residual color >> Each of the coated samples is 25 cm × 30 c.
m, and after performing the same development processing as the sensitometry processing, each of the obtained developed samples was visually evaluated in the following five stages. Table 2 shows the results.

5: Good with no residual color at all 4: Slight residual color on the whole but no problem in practical use 3: Pale residual color on the whole, lower limit of practical use 2: Dyes in some places 1: The residual color of the dye is strong on one side and is at a level that cannot be used. << Evaluation of Sharpness >> Each of the coated samples cut into 25 cm × 30 cm was sensitized. After performing the same exposure and development treatments as the metrology treatment, each of the resulting developed samples 1 to 1 was obtained.
6 was visually evaluated in the following four grades.
Table 2 shows the results.

A: very sharp B: good but slightly blurred C: blur is noticeable and there is some difficulty in interpretation D: difficult to read due to blur << Evaluation of sharpness after storage >> 25 cm × 30 cm Each of the cut coated applied samples was stored under the same conditions as the evaluation of the raw preservability, and then subjected to the same exposure and development processing as in the sensitometry process. ,
A four-level evaluation was performed as described above. Table 2 shows the results.

[0260]

[Table 2]

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

[0262]

According to the present invention, a photothermographic material for forming an X-ray image having good sharpness without contamination by a crossover cut dye, an X-ray image forming unit using the same and an X-ray image forming unit
A line image recording method was obtained.

Claims (8)

[Claims] 1. A photothermographic material having at least one photothermographic layer containing photosensitive silver halide on both sides of a support, wherein at least one layer between the support and the photothermographic layer is provided. One layer contains a dye that is bleached by heat or light, and the photosensitive layer and the layer containing the dye are applied using a coating solution in which 30% or more of the solvent is water. A photothermographic material comprising: 2. The photothermographic material according to claim 1, wherein the photosensitive silver halide is spectrally sensitized with a sensitizing dye so that a maximum photosensitive wavelength is 300 nm or more and 600 nm or less. 3. The photothermographic material according to claim 1, wherein the photosensitive silver halide is chemically sensitized with a noble metal or a chalcogen compound. 4. The photothermographic material according to claim 1, further comprising at least one compound represented by the general formula 1. Embedded image [In the formula, Hal ₁ and Hal ₂ represent a halogen atom. H
al ₁ and Hal ₂ may be the same or different. X represents an anionic group. R ₁ represents a group having a carbonyl group as a partial structure, and R ₂ and R ₃ represent a substituent which can be substituted on a nitrogen atom or a hydrogen atom. R _{1 to} R ₃ do not bond to each other so as to form a cyclic structure in which the nitrogen atom is an inner ring atom. n represents 1 or 2. ] 5. An X-ray image forming unit, 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. 6. The X-ray image forming unit according to claim 5, wherein the X-ray intensifying screen has a maximum emission spectrum by X-rays in a range from 300 nm to 600 nm. 7. An X-ray image recording method, wherein an image is obtained by exposing an X-ray to the X-ray image forming unit according to claim 5 using an X-ray generator as a light source. 8. A photothermographic material, on which an image has been recorded by the X-ray image recording method according to claim 7, is provided at 100 ° C. to 150 ° C.
An image forming method characterized in that an image is obtained by heating to ° C.