JP2001022021A - Heat developable photosensitive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a heat developable photosensitive material having high sensitivity, high contrast and little fog by incorporating a specified amount of a solvent into a treat developable photosensitive material containing an organic silver salt, photosensitive silver halide, a reducing agent and a contrast enhancer on the substrate. SOLUTION: In the heat developable photosensitive material containing an organic silver salt, photosensitive silver halide, a reducing agent and a contrast enhancer on the substrate, 10-150 mg/m2 solvent is contained. The solvent content of a back layer disposed by coating on the side of the substrate opposite to the photosensitive layer side is 50 mg/m2. The contrast enhancer is represented by the formula, wherein A0 is an aliphatic group, an aromatic group, a heterocyclic group or -G0-D0, B0 is a blocking group, A1 and A2 are each H or one of A1 and A2 is H and the other is acyl or the like, G0 is -COCO-, -CSor the like and D0 is H, an aliphatic group, an aromatic group, a heterocyclic group or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a photothermographic material.

[0002]

2. Description of the Related Art Conventionally, in the field of printing plate making and medical treatment, waste liquids caused by wet processing of image forming materials have become a problem in terms of workability. Weight loss is strongly desired. Therefore, laser
There is a need in the art for photothermographic materials for photographic applications that can be efficiently exposed with an imagesetter or laser imager and that can form high resolution, clear black images.

As this technique, for example, US Pat.
No. 152,904, No. 3,487,075 and D.C.
"Dry Silver Photographi" by Morgan
c Materials) "(Handbook of
Imaging Materials, Marcel
Dekker, Inc. 48, 1991), a photothermographic material containing an organic silver salt, photosensitive silver halide particles, a reducing agent and a binder on a support is known.

[0004] These photothermographic materials form a photographic image by a heat development process, and include a reducible silver source (organic silver salt), a photosensitive silver halide, a reducing agent and, if necessary, a silver salt. A color toning agent for suppressing color tone is usually contained in a dispersed state in an (organic) binder matrix.

The photothermographic material described above is stable at room temperature, and is developed by heating to a high temperature (for example, 80 ° C. to 140 ° C.) after exposure. 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 production of such a photothermographic material, the coating composition is often applied in a state of being dissolved in an organic solvent such as methyl ethyl ketone or acetone. In the photosensitive material using the organic solvent described above,
As described in JP-A-6-301140, there is known a dry silver salt photoreceptor in which the amount of residual solvent after coating is kept constant to thereby reduce fluctuations in development temperature and concentration over time.

However, in the above photoreceptor,
Since no high contrast agent is used, there is a problem in that gradation adjustment during raw preservation of the photographic material for printing plate making cannot be sufficiently prevented only by adjusting the amount of the solvent in the layer.

For printing plate making, a light-sensitive material capable of obtaining a high-contrast image is required, and such high-contrast technology is disclosed in US Pat. Nos. 5,545,505 and 5,464,738. It is known to use a hydrazine derivative for the above.

It has been found that, in a photosensitive material employing these high contrast techniques, if the amount of the solvent in the photosensitive material is large, the high contrast is lost due to softening during development, fogging and the like. Further, when the amount of the solvent is too small, there is a problem that the sensitivity is greatly reduced. Then, improvement of the above-mentioned problem was demanded.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a photothermographic material having high sensitivity, high contrast and low fog.

[0011]

The above objects of the present invention have been attained by the following items 1-3.

1. A photothermographic material containing an organic silver, a photosensitive silver halide, a reducing agent and a contrast agent on a support, wherein the photothermographic material contains 10 to 150 mg / m ^{2 of a} solvent. Photosensitive material.

2. In a photothermographic material containing an organic silver, a photosensitive silver halide, a reducing agent and a high contrast agent on a support, the amount of the solvent on the photosensitive layer side of the support is 10 to 150.
mg / m ² , and the amount of solvent in the back layer coated on the support opposite to the photosensitive layer with the support interposed therebetween is not more than 50 mg / m ^2. Characteristic photothermographic material.

3. 3. The photothermographic material according to the above item 1 or 2, wherein the high contrast agent is represented by the following general formula [H].

[0015]

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In the formula, A ₀ represents an aliphatic group, an aromatic group, a heterocyclic group or a -G ₀ -D ₀ group, B ₀ represents a blocking group, and A ₁ and A ₂ are both hydrogen atoms or one of them. Represents a hydrogen atom and the other represents an acyl group, a sulfonyl group or an oxalyl group. Here, G ₀ is a -CO- group, a -COCO- group,-
CS-group, -C (= NG ₁ D ₁ ) -group, -SO- group, -S
O ₂ - group or _{-P (O) (G 1 D} 1) - represents a group, G ₁ is a bond, -O- group, -S- group, or -N (D ₁₎ - represents a group, D ₁ Represents an aliphatic group, an aromatic group, a heterocyclic group or a hydrogen atom, and when a plurality of D ₁ are present in the molecule, they may be the same or different. D ₀ is a hydrogen atom,
Represents an aliphatic group, an aromatic group, a heterocyclic group, an amino group, an alkoxyl group, an aryloxy group, an alkylthio group or an arylthio group.

Hereinafter, the present invention will be described in more detail.

The solvent contained in the photothermographic material of the present invention will be described.

Examples of the solvent contained in the photothermographic material of the present invention include organic solvents, water and the like.

Examples of the organic solvent include ketones such as acetone, isophorone, ethyl amyl ketone, methyl ethyl ketone, and methyl isobutyl ketone. As alcohols methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol,
Examples thereof include diacetone alcohol, cyclohexanol, and benzyl alcohol. Glycols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, hexylene glycol and the like. Examples of ether alcohols include ethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and the like. Examples of ethers include ethyl ether, dioxane, and isopropyl ether.

Examples of the esters include ethyl acetate, butyl acetate, amyl acetate, and isopropyl acetate. Examples of the hydrocarbons include n-pentane, n-hexane, n-heptane, cyclohexane, benzene, toluene, xylene and the like. Examples of chlorides include methyl chloride, methylene chloride, chloroform, and dichlorobenzene. Examples of the amines include monomethylamine, dimethylamine, triethanolamine, ethylenediamine, and triethylamine. Other examples include water, formamide, dimethylformamide, nitromethane, pyridine, toluidine, tetrahydrofuran, acetic acid and the like.

Of the above descriptions, water, ketones such as MEK (methyl ethyl ketone) and acetone, alcohols such as methanol, ethanol and isopropanol, toluene, xylene and ethyl acetate are preferably used. These solvents can be used alone or in combination of several kinds.

The content of the above-mentioned organic solvent, water and the like in the photosensitive material can be adjusted by changing conditions such as temperature conditions in a drying step after the coating step.

For example, the content of the organic solvent can be measured by gas chromatography under conditions suitable for detecting the solvent.

As a method for analyzing water, a sample can be heated using a head sampler model HP7694 manufactured by Hewlett-Packard Company, and the amount of evaporated water can be quantified by the Karl Fischer method.

Further, the sample is cut into a specific size, and dried in a thermo machine containing a desiccant such as silica gel (conditions are 60 ° C. or more and 3 days or more). By measuring, the amount of the solvent in the sample may be calculated.

The amount of the solvent contained in the photothermographic material of the present invention is 10 to 150 mg / m ² , and the amount of the solvent contained in the layer on the photosensitive layer side is 10 to 100 mg / m ^2.
/ M ² are preferred, more preferably 10～60Mg / m ²
It is. The amount of the solvent in the back layer formed on the support opposite to the photosensitive layer side with respect to the support is 50 m
g / m ² or less. In the present invention, when the content of the solvent in the photothermographic material is in the above-mentioned range, a thermosensitive material having high contrast, high sensitivity, and low fog density can be obtained.

In order to obtain a photothermographic material containing a solvent as described above, the solid content of the coating solution during production is preferably 1 to 10% for each of an undercoat layer, a photosensitive emulsion, a back layer and the like. 45 wt% is preferred. In addition, W
The thickness of a single layer is 5 μm to 100 μm. In the simultaneous multilayer, it is preferable that the thickness be 10 to 250 μm on one side. As drying conditions after application, the drying temperature is 50 to 100 ° C.,
The drying time is preferably set to 1 to 60 minutes, more preferably the drying temperature is 65 to 90 ° C., and the drying time is 2 to
20 minutes.

The amount of air flow on the surface of the light-sensitive material in the drying step is preferably 5 to 300 m ³ / min per 1 m of the width of the light-sensitive material. The larger the air volume is, the better the drying of the photosensitive material is. However, the sensitization of the air volume in the early stage of drying tends to cause uneven drying and fog. It is preferable that the time of １ ／ is adjusted to 100 m ³ / min as the air volume.

The distance between the nozzle for blowing air during drying and the photosensitive material is preferably 5 to 4000 mm, more preferably 20 to 300 mm.

The nozzle pressure described above is 0.5 to 100 m
mAq is preferable, and the number of nozzles is 5 /
m ² -100 / m ² is preferred.

It is also preferable to perform seasoning after drying once for 0.5 to 20 days at a temperature of 60 ° C. or less.

The contrast agent used in the present invention will be described.

The photothermographic material of the present invention contains a high contrast agent. As the high contrast agent, a hydrazine derivative or a compound represented by the following general formula [G] is preferable.

As the hydrazine derivative, a compound represented by the following general formula [H] is preferable.

[0036]

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[0037] In the formula, A ₀ is an aliphatic group which may have a substituent, respectively, an aromatic group, a heterocyclic group or -G ₀ -D ₀ group, B ₀ represents a blocking group, A _1, A ₂ represents a hydrogen atom or one of them represents a hydrogen atom and the other represents an acyl group, a sulfonyl group or an oxalyl group. Here, G ₀ is −C
O-group, -COCO- group, -CS- group, -C (= NG ₁
D ₁ ) —, —SO—, —SO ₂ —, or —P (O)
(G ₁ D ₁ ) —, wherein G ₁ is a mere bond, —O—
A group, —S— group or —N (D ₁ ) — group, wherein D ₁ represents an aliphatic group, an aromatic group, a heterocyclic group or a hydrogen atom, and when a plurality of D ₁ are present in a molecule, They can be the same or different. D ₀ represents a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, an amino group, an alkoxyl group, an aryloxy group, an alkylthio group, or an arylthio group.

In the general formula [H], the aliphatic group represented by A ₀ preferably has 1 to 30 carbon atoms, particularly preferably a straight-chain, branched or cyclic alkyl group having 1 to 20 carbon atoms. For example, a methyl group, an ethyl group, a t-butyl group,
Octyl group, cyclohexyl group, benzyl group, and these further include appropriate substituents (for example, aryl group, alkoxyl group, aryloxy group, alkylthio group, arylthio group, sulfoxy group, sulfonamide group, sulfamoyl group, acylamino group, Ureido group).

In the general formula [H], the aromatic group represented by A ₀ is preferably a monocyclic or condensed-ring aryl group.
For example, a benzene ring or a naphthalene ring is mentioned, and A ₀
The heterocyclic group represented by is preferably a heterocyclic ring containing at least one hetero atom selected from nitrogen, sulfur, and oxygen atom in a single ring or a condensed ring, for example, a pyrrolidine ring,
Imidazole ring, a tetrahydrofuran ring, a morpholine ring, a pyridine ring, a pyrimidine ring, a quinoline ring, a thiazole ring, a benzothiazole ring, a thiophene ring, a furan ring, and, in -G ₀ -D ₀ group represented by A _0, G ₀ represents a -CO- group, -COCO- group, -CS- group, -C (= N
G ₁ D ₁ ) —, —SO—, —SO ₂ —, or —P
(O) represents a (G ₁ D ₁ ) — group. G ₁ is just a bond,
O—, —S— or —N (D ₁ ) —, wherein D ₁ represents an aliphatic group, an aromatic group, a heterocyclic group or a hydrogen atom;
When multiple D ₁ are present in a molecule, they may be the same or different. D ₀ represents a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, an amino group, an alkoxyl group, an aryloxy group, an alkylthio group, an arylthio group,
Preferred D ₀ includes a hydrogen atom, an alkyl group, an alkoxyl group, an amino group and the like. Aromatic groups A _0, heterocyclic group or -G ₀ -D ₀ group may have a substituent.

Particularly preferred as A ₀ are an aryl group and a -G ₀ -D ₀ group.

In the general formula [H], A ₀ preferably contains at least one of a diffusion-resistant group or a silver halide adsorbing group. As the diffusion-resistant group, a ballast group commonly used in immobile photographic additives such as couplers is preferable, and as the ballast group, a photographically inert alkyl group, alkenyl group, alkynyl group, alkoxyl group, phenyl group,
Examples thereof include a phenoxy group and an alkylphenoxy group, and the total number of carbon atoms in the substituent is preferably 8 or more.

In the general formula [H], examples of the silver halide adsorption promoting group include thiourea, thiourethane group, mercapto group, thioether group, thione group, heterocyclic group, thioamide heterocyclic group, mercapto heterocyclic group, 64-9
No. 0439.

In the general formula [H], B ₀ represents a blocking group, preferably a -G ₀ -D ₀ group, and G ₀ represents-
CO- group, -COCO- group, -CS- group, -C (= NG
₁ D ₁₎ - group, -SO- group, -SO ₂ - group or -P
(O) A preferred (G ₀ ) representing a (G ₁ D ₁ ) — group is
C _O - group, -COCO- group, and the like, G ₁ is a single bond, -O- group, -S- group, or -N (D ₁₎ - represents a group, D ₁ is an aliphatic group, an aromatic Represents a group, a heterocyclic group or a hydrogen atom, and when a plurality of D ₁ are present in a molecule, they may be the same or different. D ₀ represents a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, an amino group, an alkoxyl group, an aryloxy group, an alkylthio group, or an arylthio group, and preferred D ₀ is a hydrogen atom, an alkyl group, an alkoxyl group, And an amino group. A ₁ ,
A ₂ is a hydrogen atom, or one is a hydrogen atom, and the other is an acyl group (acetyl group, trifluoroacetyl group, benzoyl group, etc.), a sulfonyl group (methanesulfonyl group, toluenesulfonyl group, etc.), or an oxalyl group (ethoxalyl group) Etc.).

Next, specific examples of the compound represented by the general formula [H] are shown below, but it should not be construed that the invention is limited thereto.

[0045]

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[0046]

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[0047]

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[0048]

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[0049]

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[0050]

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More preferred hydrazine derivatives are represented by the following general formulas (H-1), (H-2), (H-3) or (H-
It is a compound represented by 4).

[0052]

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In the formula, R ₁₁ , R ₁₂ and R ₁₃ each represent an aryl group or a heteroaryl group. R ₁₄ represents a heterocyclic oxy group or a heteroarylthio group. A ₁ ,
A ₂ represents a hydrogen atom or one of them represents a hydrogen atom and the other represents an acyl group, an alkylsulfonyl group or an oxalyl group.

[0054]

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In the formula, R ₂₁ represents a substituted or unsubstituted alkyl group, aryl group or heteroaryl group. R ₂₂
Represents hydrogen, an alkylamino group, an arylamino group, or a heteroarylamino group. A ₁ and A ₂ are represented by the general formula (H-1)
Synonymous with that of

[0056]

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In the formula, G ₃₁ and G ₃₂ represent a — (CO) p- group,
C (= S)-group, sulfonyl group, sulfoxy group, -P
(＝ O) represents an R ₃₃ — group or an iminomethylene group, p represents an integer of 1 or 2, and R ₃₃ represents an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkoxyl group, an alkenyloxy group, an alkynyloxy group. , An aryloxy group or an amino group. However, when G ₃₁ is a sulfonyl group, G ₃₂ is not a carbonyl group. R ₃₁ and R ₃₂ represent a monovalent substituent. A ₁ and A ₂ have the same meanings as those in formula (H-1).

[0058]

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In the formula, R ₄₁ , R ₄₂ and R ₄₃ each represent an aryl group or a heteroaryl group. R ₄₄ and R ₄₅ represent an alkyl group. A ₁ and A ₂ have the same meanings as those in formula (H-1).

In the general formula (H-1), the aryl group represented by R ₁₁ , R ₁₂ and R ₁₃ is a phenyl group,
Examples include a methylphenyl group and a naphthyl group, and examples of the heteroaryl group include a triazole residue, an imidazole residue, a pyridine residue, a furan residue, and a thiophene residue. Further, R ₁₁ , R ₁₂ and R ₁₃ may be bonded via an arbitrary linking group. Examples of the substituent which R ₁₁ , R ₁₂ and R ₁₃ may have include an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a heterocyclic group containing a quaternized nitrogen atom (a pyridinio group) Etc.), a hydroxy group, an alkoxyl group (including a group repeatedly containing an ethyleneoxy group or a propyleneoxy group unit), an aryloxy group, an acyloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a urethane group, Carboxyl group, imide group, amino group, carbonamide group, sulfonamide group, ureido group, thioureido group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group,
Quaternary ammonium group, (alkyl, aryl or heterocycle) thio group, mercapto group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) sulfinyl group, sulfo group, sulfamoyl group, acylsulfamoyl group, (alkyl or Examples thereof include an (aryl) sulfonyluureido group, an (alkyl or aryl) sulfonylcarbamoyl group, a halogen atom, a cyano group, a nitro group, and a phosphoric amide group. All of R ₁₁ , R ₁₂ and R ₁₃ are preferably phenyl groups, and more preferably all are unsubstituted phenyl groups.

The heteroaryloxy group represented by R ₁₄ includes a pyridyloxy group, an indolyloxy group, a benzothiazolyloxy group, a benzimidazolyloxy group,
A furyloxy group, a thienyloxy group, a pyrazolyloxy group, an imidazolyloxy group, and the like.Examples of the heteroarylthio group include a pyridylthio group, a pyrimidylthio group, an indolylthio group, a benzothiazolylthio group, a benzimidazolylthio group, a furylthio group, Examples include a thienylthio group, a pyrazolylthio group, and an imidazolylthio group. R ₁₄ is preferably a pyridyloxy group or a thienyloxy group. The acyl group represented by A ₁ or A ₂ includes an acetyl group, a trifluoroacetyl group, a benzoyl group, and the like. The sulfonyl group includes a methanesulfonyl group, a toluenesulfonyl group, and the like, and the oxalyl group includes ethoxalyl. Groups. A ₁ , A ₂
Both are preferably hydrogen atoms.

In the general formula (H-2), examples of the alkyl group represented by R ₂₁ include a methyl group, an ethyl group, a t-butyl group, a 2-octyl group, a cyclohexyl group, a benzyl group and a diphenylmethyl group. And an aryl group, a heteroaryl group, and a substituent which may be present include R
₁₁ is the same as R ₁₂ and R _13. R ₂₁ is preferably an aryl group or a heteroaryl group, and particularly preferably a phenyl group. The alkylamino group represented by R _22, methylamino group, ethylamino group, propylamino group, butylamino group, dimethylamino group, diethylamino group, etc. ethylmethylamino group. Examples of the arylamino group anilino Examples of the group and heteroaryl group include a thiazolylamino group, a benzimidazolylamino group, and a benzthiazolylamino group. R ₂₂
Is preferably a dimethylamino group or a diethylamino group.

In the general formula (H-3), the substituents represented by R ₃₁ and R ₃₂ are the same as those described in the general formula (H-1), but are preferably an alkyl group or an aryl group. , A heteroaryl group, an alkoxyl group or an amino group, further an aryl group or an alkoxyl group, particularly preferably R ₃₁ is a phenyl group and R ₃₂ is
a t-butoxycarbonyl group. G ₃₁ and G ₃₂ are preferably a —CO— group, a —COCO— group, a sulfonyl group or a —CS— group, and more preferably both are —C—.
This is the case of an O- group or a sulfonyl group.

In formula (H-4), R ₄₁ , R ₄₂ and R ₄₃ are the same as R ₁₁ , R ₁₂ and R ₁₃ in formula (H-1).
Is synonymous with Preferably, all are phenyl groups, and all are unsubstituted phenyl groups. R ₄₄ , R ₄₅
As the alkyl group represented by, a methyl group, an ethyl group,
Examples thereof include a t-butyl group, a 2-octyl group, a cyclohexyl group, a benzyl group, a diphenylmethyl group, and the like. Preferably, both are ethyl groups.

Specific examples of the compounds represented by formulas (H-1) to (H-4) are shown below, but the invention is not limited thereto.

[0066]

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[0067]

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[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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[0073]

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Other hydrazine derivatives which can be preferably used include compounds H-1 to H-29 described in columns 11 to 20 of US Pat. No. 5,545,505.
U.S. Pat. No. 5,464,738, column 9 to column 1
Compounds 1 to 12 described in 1. These hydrazine derivatives can be synthesized by a known method.

The hydrazine derivative-added layer is a photosensitive layer containing silver halide and / or a layer adjacent to the photosensitive layer. The optimum amount is not uniform depending on the particle size of the silver halide grains, the halogen composition, the degree of chemical sensitization, the type of the inhibitor, etc., but is preferably from 10 ^-6 mol per mol of silver halide.
The range is preferably about 10 ^-1 mol, particularly preferably 10 ^-5 mol to 10 ^-2 mol.

Next, the compound represented by formula (G) will be described.

[0077]

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In the general formula [G], X and R are represented in the form of cis. However, the general formula [G] includes X and R in the form of trans. This is the same in the structural representation of a specific compound.

In the formula, X represents an electron-withdrawing group, W represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a halogen atom, an acyl group, a thioacyl group, an oxalyl group, an oxyoxalyl group. Group, thiooxalyl group, oxamoyl group, oxycarbonyl group, thiocarbonyl group, carbamoyl group, thiocarbamoyl group,
Sulfonyl group, sulfinyl group, oxysulfinyl group, thiosulfinyl group, sulfamoyl group, oxysulfinyl group, thiosulfinyl group, sulfinamoyl group, phosphoryl group, nitro group, imino group, N-carbonylimino group, N-sulfonylimino group, dicyano It represents an ethylene group, an ammonium group, a sulfonium group, a phosphonium group, a pyrylium group, or an immonium group.

R represents a halogen atom, a hydroxy group, an alkoxyl group, an aryloxy group, a heterocyclic oxy group, an alkenyloxy group, an acyloxy group, an alkoxycarbonyloxy group, an aminocarbonyloxy group, a mercapto group, an alkylthio group, an arylthio group, Organic or inorganic salts of ring thio group, alkenylthio group, acylthio group, alkoxycarbonylthio group, aminocarbonylthio group, hydroxy group or mercapto group (for example, sodium salt, potassium salt, silver salt, etc.), amino group, alkyl Amino group, cyclic amino group (for example, pyrrolidino group),
It represents an acylamino group, an oxycarbonylamino group, a heterocyclic group (e.g., a 5- to 6-membered nitrogen-containing heterocyclic ring such as a benzotriazolyl group, an imidazolyl group, a triazolyl group, or a tetrazolyl group), a ureido group, or a sulfonamide group. X and W, and X and R may be bonded to each other to form a cyclic structure. The ring formed by X and W includes, for example, pyrazolone, pyrazolidinone, cyclopentanedione, β-
Ketoractone, β-ketolactam and the like.

The general formula [G] will be further described.
Is a substituent whose Hammett's substituent constant σp can take a positive value. Specifically, a substituted alkyl group (eg, halogen-substituted alkyl), a substituted alkenyl group (eg, cyanovinyl), a substituted / unsubstituted alkynyl group (eg, trifluoromethylacetylenyl, cyanoacetylenyl), and a substituted aryl group (eg, cyanovinyl) Phenyl, etc.), substituted / unsubstituted heterocyclic groups (pyridyl, triazinyl, benzoxazolyl, etc.), halogen atoms, cyano groups, acyl groups (acetyl, trifluoroacetyl, formyl, etc.),
Thioacetyl group (thioacetyl, thioformyl, etc.), oxalyl group (methyloxalyl, etc.), oxyoxalyl group (ethoxalyl, etc.), thiooxalyl group (ethylthiooxalyl, etc.), oxamoyl group (methyloxamoyl, etc.), oxycarbonyl group (ethoxycarbonyl, etc.) etc),
Carboxyl group, thiocarbonyl group (such as ethylthiocarbonyl), carbamoyl group, thiocarbamoyl group, sulfonyl group, sulfinyl group, oxysulfonyl group (such as ethoxysulfonyl), thiosulfonyl group (such as ethylthiosulfonyl), sulfamoyl group, and oxysulfinyl Group (such as methoxysulfinyl), thiosulfinyl group (such as methylthiosulfinyl), sulfinamoyl group,
Sphinamoyl group, phosphoryl group, nitro group, imino group, N-carbonylimino group (N-acetylimino, etc.), N-sulfonylimino group (N-methanesulfonylimino, etc.), dicyanoethylene group, ammonium group, sulfonium group, phosphonium Groups, a pyrylium group, and an immonium group, and a heterocyclic group in which an ammonium group, a sulfonium group, a phosphonium group, an immonium group, and the like form a ring is also included. Particularly preferred as the σp value is a substituent having a value of 0.30 or more.

Examples of the alkyl group represented by W include methyl, ethyl, trifluoromethyl and the like, examples of the alkenyl group include vinyl, halogen-substituted vinyl and cyanovinyl, and examples of the alkynyl group include acetylenyl and cyanoacetylenyl. Examples of the group include nitrophenyl, cyanophenyl, and pentafluorophenyl, and examples of the heterocyclic group include pyridyl, pyrimidyl, triazinyl, succinimide, tetrazolyl, triazolyl, imidazolyl, and benzoxazolyl. W is σ
A p-value is preferably a positive electron-withdrawing group, and more preferably, the value is 0.30 or more.

Among the above substituents for R, preferred are a hydroxy group, a mercapto group, an alkoxyl group, an alkylthio group, a halogen atom, an organic or inorganic salt of a hydroxy group or a mercapto group, and a heterocyclic group. Examples include an organic or inorganic salt of a hydroxy group, an alkoxyl group, a hydroxy group or a mercapto group, and a heterocyclic group, and particularly preferably an organic or inorganic salt of a hydroxy group, a hydroxy group or a mercapto group.

Further, among the substituents of X and W, those having a thioether bond in the substituent are preferable.

Next, specific examples of the compound represented by the general formula [G] are shown below, but the present invention is not limited thereto.

[0086]

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[0087]

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[0088]

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[0089]

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[0090]

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[0091]

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[0092]

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[0093]

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[0094]

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[0095]

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[0096]

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[0097]

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[0098]

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[0099]

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[0100]

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[0101]

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[0102]

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[0103]

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[0104]

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[0105]

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[0106]

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[0107]

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[0108]

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[0109]

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[0110]

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The photothermographic material of the present invention includes hydroxylamine compounds, alkanolamine compounds and ammonium phthalate compounds described in US Pat. No. 5,545,505, and US Pat. No. 5,545,507. Hydroxamic acid compounds; N described in 5,558,983
-Acyl-hydrazine compounds, 5,545,515
Acrylonitrilo compound described in No. 5,937,
No. 449, it is preferable to add a high-contrast accelerator such as a hydrogen atom donor compound such as benzhydrol, diphenylphosphine, dialkylpiperidine or alkyl-β-ketoester. Among them, a quaternary onium compound represented by the following general formula (P) is preferably used.

[0112]

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In the formula, Q represents a nitrogen atom or a phosphorus atom;
R ₁ , R ₂ , R ₃ and R ₄ each represent a hydrogen atom or a substituent, and X ⁻ represents an anion. Incidentally, R _{1 to} R ₄ may be connected to each other to form a ring.

In the general formula (P), the substituents represented by R _{1 to} R ₄ include an alkyl group (a methyl group, an ethyl group,
Propyl group, butyl group, hexyl group, cyclohexyl group, etc., alkenyl group (allyl group, butenyl group, etc.), alkynyl group (propargyl group, butynyl group, etc.), aryl group (phenyl group, naphthyl group, etc.), heterocyclic group (Piperidinyl group, piperazinyl group, morpholinyl group, pyridyl group, furyl group, thienyl group, tetrahydrofuryl group, tetrahydrothienyl group, sulfolanyl group, etc.), amino group and the like.

The ring which may be formed by connecting R _{1 to} R ₄ to each other includes a piperidine ring, a morpholine ring, a piperazine ring,
Examples include a quinuclidine ring, a pyridine ring, a pyrrole ring, an imidazole ring, a triazole ring, and a tetrazole ring.

The groups represented by R _{1 to} R ₄ may have a substituent such as a hydroxyl group, an alkoxyl group, an aryloxy group, a carboxyl group, a sulfo group, an alkyl group and an aryl group.

R ₁ , R ₂ , R ₃ and R ₄ are preferably a hydrogen atom and an alkyl group.

Examples of the anion represented by X ⁻ include inorganic and organic anions such as a halogen ion, a sulfate ion, a nitrate ion, an acetate ion and a p-toluenesulfonic acid ion.

More preferably, the following general formulas (Pa) and (P
a compound represented by b) or (Pc); and a compound represented by the following general formula [T].

[0120]

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In the formula, A ¹ , A ² , A ³ , A ⁴ and A ⁵ represent a group of nonmetal atoms for completing a nitrogen-containing heterocyclic ring, and may contain an oxygen atom, a nitrogen atom and a sulfur atom. And the benzene ring may be condensed. A ¹ , A ² , A ³ , A ⁴ and A ⁵
May have a substituent and may be the same or different. Examples of the substituent include an alkyl group, an aryl group, an aralkyl group, an alkenyl group, an alkynyl group, a halogen atom, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a sulfo group, a carboxy group, a hydroxy group, an alkoxyl group, and an aryloxy group. Amide group, sulfamoyl group, carbamoyl group, ureido group, amino group, sulfonamide group, sulfonyl group, cyano group, nitro group, mercapto group, alkylthio group and arylthio group. Preferred examples of A ¹ , A ² , A ³ , A ⁴ and A ⁵ include a 5- to 6-membered ring (pyridine,
Imidazole, thiazole, oxazole, pyrazine,
Each ring such as pyrimidine), and a more preferred example is a pyridine ring.

B _P represents a divalent linking group, and m represents 0 or 1. Examples of the divalent linking group include an alkylene group, an arylene group, an alkenylene _{group, -SO 2 -, - SO -} , -
O -, - S -, - CO -, - N (R 6) - (R 6 is an alkyl group, an aryl group, a hydrogen atom) represents what is configured alone or in combination. Preferred examples of B _p include an alkylene group and an alkenylene group.

R ¹ , R ² and R ⁵ each have 1 to 20 carbon atoms
Represents an alkyl group. R ¹ and R ² may be the same or different. The alkyl group represents a substituted or unsubstituted alkyl group, and the substituent is the same as the substituents described as the substituents for A ¹ , A ² , A ³ , A ⁴ and A ⁵ .

Preferred examples of R ¹ , R ² and R ⁵ include:
Each is an alkyl group having 4 to 10 carbon atoms. More preferred examples include an alkyl group substituted with an aryl group.

[0125] X _p ^- represents a counter ion necessary to neutralize the charge of the whole molecule, for example chloride, bromide,
It represents iodine ion, nitrate ion, sulfate ion, p-toluenesulfonate, oxalate and the like. n _p represents the number of counter ions required to neutralize the charge of the whole molecule, and n _p is 0 in the case of an internal salt.

[0126]

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The substituents R ₅ and R ₆ of the phenyl group of the triphenyltetrazolium compound represented by the general formula [T],
R ₇ is preferably a hydrogen atom or a compound having a negative Hammett sigma value (σP) indicating electron-withdrawing degree.

The Hammett's sigma value at the phenyl group is described in many literatures, for example, Journal of Medical Chemistry.
chemistry, 20, 304, 1977. The group having a particularly preferable negative sigma value is, for example, a methyl group (σP = −0.17 or less, all σP values) and an ethyl group (− 0.15), cyclopropyl group (-0.21), n-propyl group (-0.13), is
o-propyl group (-0.15), cyclobutyl group (-
0.15), n-butyl group (-0.16), iso-butyl group (-0.20), n-pentyl group (-0.1
5), cyclohexyl group (-0.22), amino group (-
0.66), acetylamino group (-0.15), hydroxy group (-0.37), methoxy group (-0.27), ethoxy group (-0.24), propoxy group (-0.2
5), butoxy group (-0.32), pentoxy group (-
0.34), etc., each of which has the general formula [T]
Is useful as a substituent of the compound of

N represents 1 or 2, and examples of the anion represented by X _T ^n- include halogen ions such as chloride ion, bromide ion and iodide ion, nitric acid, sulfuric acid, and the like.
Acid radicals of inorganic acids such as perchloric acid, acid radicals of organic acids such as sulfonic acid and carboxylic acid, anionic activators, specifically p-
Lower alkylbenzene sulfonic acid anions such as toluene sulfonic acid anion; higher alkyl benzene sulfonic acid anions such as p-dodecyl benzene sulfonic acid anion; higher alkyl sulfate anions such as lauryl sulfate anion; boric acid anions such as tetraphenyl boron; Dialkyl sulfosuccinate anions such as 2-ethylhexyl sulfosuccinate anion,
Examples thereof include higher fatty acid anions such as cetyl polyethenoxy sulfate anion, and polymers having an acid radical attached to a polymer such as polyacrylate anion.

Hereinafter, specific examples of the quaternary onium compound will be shown below, but it should not be construed that the invention is limited thereto.

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[0132]

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[0133]

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[0134]

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[0135]

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[0136]

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[0137]

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[0138]

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[0139]

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[0140]

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The above quaternary onium compound can be synthesized with reference to a known method. For example, the above tetrazolium compound can be synthesized as described in Chemical Reviews 55 p. 335
To 483 can be referred to.

The addition amount of these quaternary onium compounds is about 1 × 10 ^-8 to 1 mol, preferably 1 × 10 ^-7 to 1 × 10 ^-1 mol per mol of silver halide. These can be added to the light-sensitive material at any time from the time of silver halide grain formation to the time of coating.

The quaternary onium compound may be used alone or
More than one species may be used in combination. The compound may be added to any of the constituent layers of the photosensitive material, but is preferably added to at least one of the constituent layers on the side having the photosensitive layer, and further to the photosensitive layer and / or a layer adjacent thereto.

The silver halide grains used in the present invention function as an optical sensor. In the present invention, the average particle size is preferably 0.1 μm or less, more preferably 0.01 μm to 0.1 μm, particularly preferably 0.01 μm to 0.1 μm, in order to suppress white turbidity after image formation and obtain good image quality. It is 0.02 μm to 0.08 μm.

When the silver halide grains are cubic or octahedral, so-called normal crystals, the grain size refers to the length of the edge of the silver halide grains. In the case of non-normal crystals, for example, in the case of spherical, rod-shaped, or tabular grains, the diameter of a sphere equivalent to the volume of silver halide grains is indicated. Further, the silver halide is preferably monodispersed.

The term “monodispersion” as used herein means a case where the degree of monodispersion determined by the following equation is 40% or less. In the present invention, the monodispersity is 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 In the invention, the silver halide particles have an average particle size of 0.1.
μm or less and more preferably monodisperse particles,
Within this range, the graininess of the image is also improved.

The shape of the silver halide grains is not particularly limited, but it is preferable that the ratio occupied by the Miller index [100] plane is high, and this ratio is 50% or more, more preferably 7%.
It is preferably at least 0%, particularly preferably at least 80%. The ratio of the Miller index [100] plane is determined by the T.M. Tani, J .; Imaging Sci. , 29,
165 (1985).

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.mu.
When m, the aspect ratio = r / h means 3 or more. Among them, the aspect ratio is more preferably 3 or more and 50 or less. The particle size is preferably 0.1 μm or less, more preferably 0.01 μm to 0.08 μm. These are described in U.S. Patent Nos. 5,264,337, 5,314,798, and 5,320,958, and the desired tabular grains can be obtained with reference to the above patents. .

When these tabular grains are used in the present invention, the sharpness of an image is further 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. AgX particles used in the present invention are P.A. Glafk
by chimes et Physique
Photographique (Paul Monte)
l, 1967); F. Duffin's Ph
autographic Emulsion Chemi
story (published by The Focal Press, 196)
6 years). L. By Zelikman et al M
aking and Coating Photogr
aphic Emulsion (The Focal
Press, 1964) and the like, and can be prepared using an Ag emulsion prepared by a method described in US Pat.

The silver halide used in the present invention is preferably contained in an amount of 0.75 to 30% by weight based on the organic silver salt.

The silver halide used in the present invention preferably contains metal ions belonging to groups 6 to 11 of the periodic table. As the above metals, W, Fe, Co,
Ni, Cu, Ru, Rh, Pd, Re, Os, Ir, P
t and Au are preferred.

These metal ions can be introduced into silver halide in the form of a metal complex or a metal complex ion. As these metal complexes or metal complex ions, hexacoordinate metal complexes represented by the following general formula are preferable.

In the formula [ML ₆ ] ^m , M is a transition metal selected from the elements of Groups 6 to 11 of the periodic table, L is a ligand, and m is 0,-, 2-, 3- or 4-
Represents Specific examples of the ligand represented by L include halides (fluoride, chloride, bromide and iodide), cyanide, cyanate, thiocyanate, selenocyanate, tellurocyanate, azide and aquo. Ligand, nitrosyl, thionitrosyl and the like, preferably aquo, nitrosyl and thionitrosyl. If an aquo ligand is present, it preferably occupies one or two of the ligands. L may be the same or different.

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

Specific examples of transition metal complex ions are shown below, but the present invention is not limited to these.

[0157] 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) Cl (CN) 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- These metal ions, metal complexes or metal complex ions may be of one kind or a combination of two or more of the same and different metals. Is also good. The content of these metal ions, metal complexes or metal complex ions, generally is suitably ¹ × 10 -9 ~1 × 10 ^-2 mol per mol of silver halide, preferably 1 × 10 ^{- It is 8} to 1 × 10 ^-4 mol.

Compounds which provide these metal ions or complex ions are added during silver halide grain formation.
It is preferably incorporated into silver halide grains, and may be added at any stage before and after preparation of silver halide grains, that is, nucleation, growth, physical ripening, and chemical sensitization. It is preferably added at the stage of physical ripening, more preferably at the stage of nucleation and growth, and most preferably at the stage of nucleation.

In the addition, it may be added several times in several portions, may be added uniformly in silver halide grains, or may be added to silver halide grains.
-306236, 3-167545, 4-76
No. 534, No. 6-110146, No. 5-273683
As described in Japanese Patent Application Laid-Open No. H10-284, etc., the particles can be contained in the particles with a distribution. Preferably, a distribution can be provided inside the particles.

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 in which an aqueous solution of a powder or an aqueous solution in which a metal compound and NaCl and KCl are dissolved together is added to a water-soluble silver salt solution or a water-soluble halide solution during grain formation, or 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 metal ions or complex ions in advance during the preparation of 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 during physical ripening, or at the time of chemical ripening.

The silver halide grains used in the present invention may or may not be desalted after grain formation. When desalting is performed, methods known in the art such as a noodle method and a flocculation method are used. Can be desalted by washing with water.

The silver halide grains used in the present invention are preferably chemically sensitized. Preferred chemical sensitization methods are sulfur sensitization, as is well known in the art,
Selenium sensitization and tellurium sensitization can be used. Further, a noble metal sensitization method or a reduction sensitization method of a gold compound, platinum, palladium, an iridium compound or the like can be used. As the compound preferably used in the sulfur sensitization method, the selenium sensitization method, and the tellurium sensitization method, known compounds can be used, and the compounds described in JP-A-7-128768 can be used. Examples of tellurium sensitizers include diacyl tellurides, bis (oxycarbonyl) tellurides,
Bis (carbamoyl) tellurides, diacyl tellurides, bis (oxycarbonyl) ditellurides, bis (carbamoyl) ditellurides, compounds having a P = Te bond, tellurocarboxylates, Te-organyltellurocarboxylates, Use of (poly) tellurides, tellurides, tellurols, telluroacetals, tellurosulfonates, compounds having a P-Te bond, Te-containing heterocycles, tellurocarbonyl compounds, inorganic tellurium compounds, colloidal tellurium, etc. Can be. Compounds preferably used for the noble metal sensitization method include, for example, chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, gold selenide, US Pat. No. 2,448,060, British Patent No. 618,061 and the like. Can be preferably used.

As specific compounds for 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 are used. be able to. 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 organic silver salt used in the present invention is a reducible silver source, and is an organic acid containing a reducible silver ion source. Examples of the organic acid used in the present invention include an aliphatic carboxylic acid, a carbocyclic carboxylic acid, a heterocyclic carboxylic acid, and a heterocyclic compound.
An aliphatic carboxylic acid having 0, preferably 15 to 25 carbon atoms) and a heterocyclic carboxylic acid having a nitrogen-containing heterocyclic ring are preferably used. Moreover, when the ligand is 4.0-10.
Organic silver salt complexes having a total stability constant for silver ions of 0 are also useful.

Examples of the silver salt of an organic acid used in the present invention include Research Disclosure No. 170.
And silver salts of fatty acids (eg, silver salts of gallic acid, oxalic acid, behenic acid, arachidic acid, stearic acid, palmitic acid, lauric acid, etc.); Carboxyalkylthiourea salts (eg, 1- (3-carboxypropyl) thiourea, 1- (3-carboxypropyl) -3,3-dimethylthiourea); polymerization reaction products of aldehydes and hydroxy-substituted aromatic carboxylic acids (E.g., aldehydes (formaldehyde, acetaldehyde, butyraldehyde, etc.) and hydroxy-substituted aromatic carboxylic acids (e.g., salicylic acid, benzoic acid, 3,5-dihydroxybenzoic acid, 5,5-thiodisalicylic acid, etc.) Silver complex or the like of a polymerization reaction product of), a silver salt or complex of a thione (for example, 3- (2-carbo) (Silethyl) -4-hydroxymethyl-4-thiazoline-2-thione and 3-carboxymethyl-4-thiazoline-2-thione), imidazole, pyrazole, urazole, 1,2,4-thiazole and 1H-tetrazole, -Amino-5-benzylthio-1,2,4-triazole and benzotriazole, and complexes and salts of silver with nitrogen acids; silver salts such as saccharin and 5-chlorosalicylaldoxime; and silver salts of mercaptides . Among the organic silver salts described above, silver salts of fatty acids are preferably used, and silver behenate, silver arachidate and silver stearate are more preferably used. The aqueous organic silver salt dispersion used in the present invention can be obtained by mixing silver nitrate and an organic acid alkali metal salt.A simultaneous mixing method in which silver nitrate and silver halide are simultaneously added and mixed when an organic silver salt is formed, is used. It is preferably manufactured using

For example, after adding an alkali metal hydroxide (eg, sodium hydroxide, potassium hydroxide, etc.) to an organic acid to prepare an organic acid alkali metal salt soap (eg, sodium behenate, sodium arachidate, etc.) By using a controlled double jet method, silver nitrate and silver halide can be simultaneously added and mixed to prepare an aqueous organic silver salt dispersion used in the present invention.

Further, an aqueous organic silver salt dispersion used in the present invention can be prepared by a so-called controlled triple jet method in which an alkali metal salt of an organic acid, silver nitrate and silver halide are simultaneously added and mixed, respectively. it can.

In the present invention, from the viewpoint of simplicity in the production process, the above-mentioned method for producing an aqueous organic silver salt dispersion using the controlled double jet method is preferably used. From the viewpoint of producing a high-sensitivity photothermographic material, the method for producing an aqueous organic silver salt dispersion using the above-described controlled triple jet method is preferably used.

The photothermographic material of the present invention preferably contains a reducing agent. Examples of suitable reducing agents are described in U.S. Patent Nos. 3,770,448, 3,773,512,
No. 3,593,863 and Research D
No. 17029 and 29996, and include the following: Aminohydroxycycloalkenones (eg, 2-hydroxypiperidino-2-cyclohexenone); aminoreductones esters (eg, piperidinohexose reductone monoacetate) as precursors of reducing agents; N- Hydroxyurea derivatives (eg, Np-methylphenyl-N-hydroxyurea); hydrazones of aldehydes or ketones (eg, anthracenaldehyde phenylhydrazone); phosphoramidophenols; phosphoramidoanilines; polyhydroxybenzenes (Eg, hydroquinone, t-butyl-hydroquinone, isopropylhydroquinone, and (2,5-dihydroxy-phenyl) methylsulfone); sulfhydroxamic acids (eg, benzenesulfhydroxam) ); Sulfonamides anilines (e.g., 4-(N-
Methanesulfonamido) aniline); 2-tetrazolylthiohydroquinones (for example, 2-methyl-5- (1-
Phenyl-5-tetrazolylthio) hydroquinone); tetrahydroquinoxalines (e.g., 1,2,3,4-
Amidoximes (eg, phenylamidooxime, 2-thienylamidooxime); azines (eg, combination of aliphatic carboxylic acid arylhydrazides and ascorbic acid); combinations of polyhydroxybenzene and hydroxylamine; Reductone and / or hydrazine; Hydroxamic acids; Combination of azines and sulfonamidophenols; α-cyanophenylacetic acid derivative; Combination of bis-β-naphthol and 1,3-dihydroxybenzene derivative; 5-pyrazolones; Reducing agents; 2-phenylindane-1,3-dione and the like; chromans; 1,4-dihydropyridines (for example, 2,6-
Dimethoxy-3,5-dicarbethoxy-1,4-dihydropyridine); bisphenols (for example, bis (2
-Hydroxy-3-t-butyl-5-methylphenyl)
Methane, bis (6-hydroxy-m-tri) mesitol, 2,2-bis (4-hydroxy-
3-methylphenyl) propane, 4,5-ethylidene-
Bis (2-t-butyl-6-methyl) phenol), ultraviolet-sensitive ascorbic acid derivatives and 3-pyrazolidones. Among them, particularly preferred reducing agents are hindered phenols. Examples of the hindered phenols include compounds represented by the following general formula (A).

[0171]

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In the formula, R represents a hydrogen atom or a group having 1 to 1 carbon atoms.
Represents an alkyl group of 10 (eg, butyl group, 2,4,4-trimethylpentyl group, etc.), and R ′ and R ″ represent an alkyl group having 1 to 5 carbon atoms (eg, methyl group, ethyl group, t- Specific examples of the compound represented by the formula (A) are shown below, but the present invention is not limited thereto.

[0173]

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[0174]

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The amount of the reducing agent including the compound represented by formula (A) is preferably 1 × 1 per mol of silver.
It is from 0 ^-2 to 10 mol, especially from 1 x 10 ^{-2 to} 1.5 mol.

The photothermographic material of the present invention may contain an antifoggant. Known as an effective antifoggant is mercury ion, and the use of a mercury compound as an antifoggant in a light-sensitive material is disclosed in, for example, US Pat. No. 3,589,903. However, mercury compounds are environmentally unfavorable and are, for example, disclosed in U.S. Patent Nos. 4,546,075 and 4,452.
Non-mercury antifoggants such as those disclosed in JP-A-885-85 and JP-A-59-57234 are preferably used in the present invention.

Particularly preferred non-mercury antifoggants include US Pat. Nos. 3,874,946 and 4,753.
No. 6,999, the compound -C (X
₁ ) Heterocyclic compounds having at least one substituent represented by (X ₂ ) (X ₃ ) (where X ₁ and X ₂ each represent a halogen atom, and X ₃ represents hydrogen or a halogen atom). Can be

Other suitable antifoggants include paragraph [0030] of JP-A-9-288328.
To [0036], JP-A-9-9
Compounds described in paragraph Nos. [0062] to [0063] of US Pat. No. 0550, US Pat. No. 5,028,523 and European Patent Nos. 600,587 and 605,981.
Nos. 631,176 and the like can be used.

It is preferable to add a toning agent to the photothermographic material of the present invention for the purpose of improving the silver tone after development. Examples of suitable toning agents are Research Discl
No. 17029, which includes the following:

Imides (for example, phthalimide); cyclic imides, pyrazolin-5-ones, and quinazolinones (for example, 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 (benzothiazolinylidene))-1-methylethylidene) -2-thio-2,4
Oxazolidinedione); phthalazinone, a phthalazinone derivative or a metal salt of these derivatives (for example, 4-
(1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7-dimethyloxyphthalazinone, and 2,3
-Dihydro-1,4-phthalazinedione); a combination of phthalazinone and a sulfinic acid derivative (for example, 6-chlorophthalazinone + sodium benzenesulfinate or 8-methylphthalazinone + sodium p-trisulfonate); phthalazine + phthalate Combinations of acids; phthalazine (including adducts of phthalazine) and maleic anhydride, and phthalic acid, 2,3-naphthalenedicarboxylic acid or o-phenylene acid derivatives and anhydrides thereof (for example,
Combination with at least one compound selected from phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride; quinazolinediones, benzoxazine, naloxazine derivatives; benzoxazine-2,4-dione (Eg, 1,3-benzoxazine-2,4-dione); pyrimidines and asymmetric-triazines (eg, 2,4-dihydroxypyrimidine), and tetraazapentalene derivatives (eg,
3,6-dimercapto-1,4-diphenyl-1H, 4
H-2,3a, 5,6a-tetraazapentalene). Preferred toning agents are phthalazone or phthalazine.

The photothermographic materials of the present invention include, for example, JP-A-63-159814, JP-A-60-140335, JP-A-63-231437, JP-A-63-259651, and JP-A-6-259561.
3-304242, 63-15245, U.S. Pat. Nos. 4,639,414 and 4,740,455,
Nos. 4,741,966 and 4,751,175
No. 4,835,096.

Useful sensitizing dyes for use in the present invention include, for example, Research Disclosure Item
17643 IV-A (p. 23, December 1978), and Item 18431 (p. 437, August 1979), etc. In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of various scanner light sources can be advantageously selected. For example, JP-A-9-34078, JP-A-9-54409, and JP-A-9-806
The compounds described in No. 79 are preferably used.

In the present invention, a mercapto compound, a disulfide compound, and a thione compound are contained in order to control development by suppressing or accelerating development, to improve spectral sensitization efficiency, and to improve storage stability before and after development. be able to.

When a mercapto compound is used in the present invention, it may be of any structure,
Those represented by -SS-Ar are preferred. In the formula, M is a hydrogen atom or an alkali metal atom, and Ar represents an aromatic ring or a condensed aromatic ring having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms.

As the aromatic ring, an aromatic carbon ring and a heteroaromatic ring are used. In the present invention, a heteroaromatic ring is preferably used. As the heteroaromatic ring, for example, benzimidazole, naphthymidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzotellurazole, imidazole, oxazole, pyrazole, triazole, thiadiazole, tetrazole, triazine, pyrimidine, Pyridazine, pyrazine, pyridine, purine, quinoline or quinazolinone. The heteroaromatic ring includes, for example, a halogen atom (eg, Br and Cl), a hydroxy group, an amino group, a carboxy group, an alkyl group (eg, one or more carbon atoms, preferably
Having a substituent selected from the group consisting of a substituent having from 1 to 4 carbon atoms and an alkoxyl group (e.g., having at least one carbon atom, preferably having from 1 to 4 carbon atoms). Is also good. Examples of the mercapto-substituted heteroaromatic compound include 2-mercaptobenzimidazole and 2-mercaptobenzimidazole.
Mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-mercapto-5-methylbenzothiazole, 3-mercapto-1,2,4-triazole,
-Mercaptoquinoline, 8-mercaptopurine, 2,
3,5,6-tetrachloro-4-pyridinethiol,
-Hydroxy-2-mercaptopyrimidine, 2-mercapto-4-phenyloxazole and the like,
The present invention is not limited to these.

In the present invention, a matting agent is preferably contained on the photosensitive layer side. In order to prevent the image after thermal development from being damaged, it is preferable to provide a matting agent on the surface of the photosensitive material. Is preferably contained in a weight ratio of 0.5 to 30% based on all binders on the emulsion layer side.

The material of the matting agent used in the present invention may be either an organic substance or an inorganic substance.

For example, as the inorganic substance, Swiss Patent No. 3
Silica described in No. 30,158, French Patent No. 1,29
No. 6,995, etc., British Patent No. 1,17
Alkaline earth metals or carbonates such as cadmium and zinc described in 3,181 and the like can be used as a matting agent. As organic substances, US Pat. No. 2,322,03
7, starch derivatives described in Belgian Patent No. 625,451 and British Patent No. 981,198, polyvinyl alcohol described in Japanese Patent Publication No. 44-3643, and Swiss Patent No. 330,158. Polystyrene or polymethacrylate described in U.S. Pat.
Organic matting agents such as polyacrylonitrile described in No. 79,257 and polycarbonate described in U.S. Pat. No. 3,022,169 can be used.

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

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

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

(Standard deviation of particle size) / (average value of particle size) × 100 The matting agent used in the present invention can be contained in any constituent layer, but in order to achieve the object of the present invention, It is preferably a constituent layer other than the photosensitive layer, and more preferably the outermost layer as viewed from the support.

The method of adding the matting agent used in the present invention may be a method in which the matting agent is dispersed in a coating solution in advance, or may be sprayed after the coating solution 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.

In the present invention, a conductive compound such as a metal oxide and / or a conductive polymer can be included in the constituent layer in order to improve the chargeability. These may be contained in any layer, but are preferably contained in an undercoat layer, a backing layer, a layer between the photosensitive layer and the undercoat, and the like.

In the present invention, US Pat.
The conductive compounds described in No. 773 columns 14 to 20 are preferably used.

Various additives may be added to any of the photosensitive layer, the non-photosensitive layer, and other constituent 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, and the like may be used in addition to the above. These additives and the other additives mentioned above are used in Research Disclosure.
re Item 17029 (June 1978, p. 9-
The compound described in 15) can be preferably used.

Binders suitable for the photothermographic material of the present invention are transparent or translucent and generally colorless, and include natural polymer synthetic resins, polymers and copolymers, and other film-forming media such as gelatin, gum arabic,
Poly (vinyl alcohol), hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, poly (vinyl pyrrolidone), casein, starch, poly (acrylic acid), poly (methyl methacrylic acid), poly (vinyl chloride), poly (methacrylic acid) ), Copoly (styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinyl acetal) s (eg, poly (vinyl formal) and poly (vinyl butyral)), poly (ester) ), Poly (urethane), phenoxy resin, poly (vinylidene chloride), poly (epoxide),
Poly (carbonate) s, poly (vinyl acetate),
There are cellulose esters and poly (amides). It may be hydrophilic or non-hydrophilic. In order to protect the surface of the light-sensitive material and prevent abrasion, a non-light-sensitive layer may be provided outside the light-sensitive layer. The binder used for these non-photosensitive layers may be the same as or different from the binder used for the photosensitive layers.

In the present invention, the amount of the binder is 5 to 90 wt.% Of the total material weight on the photosensitive layer side including the photosensitive layer and the protective layer.
%, Preferably 0.5 to 20 g / m ² , and the same range is preferably used for the back layer. The total weight including binder and each material is 1 to 1 per side
30 g / m ² is preferred.

Further, in the present invention, in order to increase the speed of thermal development, the amount of binder in the photosensitive layer is 1.5 to 10 g /
m ² is preferred. More preferably 1.7 to
8 g / m ² .

The support used in the present invention may be a plastic film (for example, polyethylene terephthalate, polycarbonate, or the like) in order to prevent deformation of an image after development processing.
Polyimide, nylon, cellulose triacetate, polyethylene naphthalate) are preferred.

Among them, a preferred support is a support of polyethylene terephthalate (hereinafter abbreviated as PET) and a plastic (hereinafter abbreviated as SPS) containing a styrene polymer having a syndiotactic structure. The thickness of the support is about 50 to 300 μm, preferably 70 to 180 μm.

Further, a heat-treated plastic support can also be used. The plastics to be employed include the above-mentioned plastics. The heat treatment of the support means that after forming these supports and before the photosensitive layer is applied, at a temperature higher than the glass transition point of the support by 30 ° C. or more,
Preferably at a temperature higher than 35 ° C., more preferably 40 ° C.
It is preferable to heat at a temperature higher than ℃. However, the effect of the present invention cannot be obtained by heating at a temperature exceeding the melting point of the support.

Next, the plastic used will be described.

PET is a polyester in which all of the polyester components are made of polyethylene terephthalate. In addition to polyethylene terephthalate, terephthalic acid, naphthalene-2,6-dicarboxylic acid, isophthalic acid, butylene dicarboxylic acid, and 5-sodium sulfo acid are used as acid components. A polyester containing a modified polyester component of isophthalic acid, adipic acid or the like and a glycol component such as ethylene glycol, propylene glycol, butanediol, cyclohexanedimethanol or the like in an amount of 10 mol% or less of the entire polyester may be used.

SPS is a polystyrene having steric regularity unlike ordinary polystyrene (atactic polystyrene). The regular stereoregular structure part of SPS is called a racemo chain, and it is preferable that there are more regular parts such as two, three, five or more. In the present invention, the racemo chain is 2 It is preferably 85% or more in the chain, 75% or more in the three chains, 50% or more in the five chains, and 30% or more in the further chains. The polymerization of SPS can be carried out according to the method described in JP-A-3-131843.

As the method of forming a support and the method of producing an undercoat used in the present invention, known methods can be used. Preferably, the method described in paragraph [0030] of JP-A-9-50994 is used.
To [0070].

The photothermographic material of the present invention is for forming a photographic image by a heat development process, and includes a reducible silver source (organic silver salt), a photosensitive silver halide, a reducing agent and, if necessary, silver. It is preferable that the photothermographic material contains a color toning agent which suppresses the color tone of the present invention in a state of being usually dispersed in an (organic) binder matrix. The photothermographic material of the present invention is stable at room temperature, but is exposed to high temperature (for example,
(0 ° C.). Heating generates silver through an oxidation-reduction reaction between an organic silver salt (functioning as an oxidizing agent) and a reducing agent. This oxidation-reduction reaction is accelerated by the catalytic action of the latent image generated on the silver halide upon exposure. The silver formed by the reaction of the organic silver salt in the exposed areas provides a black image, which contrasts with the unexposed areas, resulting in the formation of an image. This reaction process proceeds without supplying a processing liquid such as water from the outside.

The photothermographic material of the present invention has at least one photosensitive layer on a 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. To control the amount or wavelength distribution of light passing through the photosensitive layer, a filter dye layer on the same side as the photosensitive layer and / or an antihalation dye layer, a so-called backing layer, may be formed on the opposite side. A dye or pigment may be included in the active layer. As the dye to be used, any compound may be used as long as it has a desired absorption in a desired wavelength range, and examples thereof include JP-A-59-6481 and JP-A-59-1.
No. 82436, U.S. Pat. No. 4,271,263, U.S. Pat. No. 4,594,312, European Patent Publication 533,0
08, European Patent Publication 652,473, JP-A-2-2-2
No. 16140, JP-A-4-348339, JP-A-7-
Compounds described in JP-A-191432 and JP-A-7-301890 are preferably used.

These non-photosensitive layers preferably contain the binder or matting agent described above, and may further contain a slip agent such as a polysiloxane compound, wax or liquid paraffin.

The light-sensitive layer may be composed of a plurality of layers, and the sensitivity may be changed to a high-sensitivity layer / low-sensitivity layer or a low-sensitivity layer / high-sensitivity layer for adjusting the gradation.

For details of the photothermographic material, see, for example, US Pat. Nos. 3,152,904 and 3,457,
No. 075, and D.A. “Dry Silver Photographic Materials (Dry Silver P) by Morgan
photographic Material) ”and D.C.
Morgan and B.A. Shelley
y) "Heat treated silver system (The
rally Processed Silver S
systems) "(Imaging Processes and Materials)
es and Materials) Neblette
Eighth Edition, Sturge, V.S. Walworth, A .; Shep
p) Edit, page 2, 1969).
Among them, in the present invention, the photosensitive material is 80 to 140
It is characterized in that an image is formed by heat development at a temperature of ° C. and no fixing is performed. Therefore, the silver halide and the organic silver salt remaining in the unexposed area remain in the photosensitive material without being removed.

In the present invention, after the heat development processing,
The optical transmission density of the light-sensitive material containing the support at 400 nm is preferably 0.2 or less. A more preferable value of the optical transmission density is 0.02 or more and 0.2 or less.

[0213]

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

Example 1 (Preparation of Subbed PET Support) A commercially available biaxially stretched heat-fixed PET film having a thickness of 100 μm was coated on both surfaces with 8 W /
m ² · m of corona discharge treatment, the following undercoating coating liquid a-1 is applied to one side to a dry film thickness of 0.8 μm, and dried to form an undercoating layer A-1, and vice versa. On the side surface, the following antistatic coating solution b-1 was applied with a dry film thickness of 0.8 μm
And dried to form an antistatic subbing layer B-
It was set to 1.

<< Undercoat Coating Solution a-1 >> Butyl acrylate (30% by weight) t-butyl acrylate (20% by weight) Styrene (25% by weight) 2-hydroxyethyl acrylate (25% by weight) copolymer latex liquid (Solid content 30%) 270 g (C-1) 0.6 g hexamethylene-1,6-bis (ethylene urea) 0.8 g polystyrene fine particles (average particle diameter 3 μm) 0.05 g colloidal silica (average particle diameter 90 μm) 0 Make up to 1 liter with 1g water.

<< Undercoat Coating Solution b-1 >> SnO ₂ / Sb (9/1 weight ratio, average particle size 0.18 μm) Amount to become 200 mg / m ² Butyl acrylate (30% by weight) Styrene (20% by weight) Glycidyl acrylate (40% by weight) copolymer latex liquid (solid content 30%) 270 g (C-1) 0.6 g Hexamethylene-1,6-bis (ethylene urea) 0.8 g Finished to 1 liter with water.

Subsequently, the undercoat layer A-1 and the undercoat layer B-1
A corona discharge of 8 W / m ² · min is applied to the upper surface of the lower layer, and the lower layer upper layer coating solution a-2 described below is coated on the lower layer A-1 so as to have a dry film thickness of 0.1 μm. Sublayer B as Layer A-2
-1 is coated with the following undercoating layer coating solution b-2 having a dry film thickness of 0.
Coating was performed as a subbing upper layer B-2 having an antistatic function so as to have a thickness of 8 μm.

<< Coating Solution a-2 for Subbing Upper Layer >> Weight of gelatin 0.4 g / m ² (C-1) 0.2 g (C-2) 0.2 g (C-3) 0.1 g Silica particles ( (Average particle size: 3 μm) 0.1 g Finish to 1 liter with water.

<< Lower Coating Upper Layer Coating Solution b-2 >> (C-4) 60 g Latex liquid containing (C-5) as a component (solid content: 20%) 80 g Ammonium sulfate 0.5 g (C-6) 12 g Polyethylene glycol ( (Weight average molecular weight: 600) 6 g Finished to 1 liter with water.

[0220]

Embedded image

[0221]

Embedded image

(Heat Treatment of Support) In the undercoat drying step of the undercoated support, the support was heated at 140 ° C.
Thereafter, it was gradually cooled.

(Preparation of silver halide emulsion A) 900 m of water
7.5 g of inert gelatin and 10 ml of potassium bromide
mg, and adjusted to a temperature of 35 ° C. and a pH of 3.0, and 370 ml of an aqueous solution containing 74 g of silver nitrate (60/3
8/2) 370 m aqueous solution containing sodium chloride, potassium bromide and potassium iodide (equimolar to silver nitrate) in a molar ratio of 8/2)
1 and K ₂ [Ir (NO) Cl ₅ ] salt in an amount of 1
× 10 ^-6 mole and rhodium chloride salt at 1 × per mole of silver
10 ^-6 mol was added by the controlled double jet method, keeping the pAg at 7.7. Thereafter, 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene was added, the pH was adjusted to 8 with NaOH, and the pAg was adjusted to 6.5 to perform reduction sensitization. Coefficient of variation of the projected diameter area of 10% with a dispersion degree of 8%, [100]
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 was performed.

(Preparation of Fatty Acid Sodium Salt Solution) 945
32.4 g of behenic acid and 9.9 of arachidic acid in ml of pure water
g and stearic acid 5.6 g were dissolved at 90 ° C. Next, while stirring at a high speed, a 1.5 M aqueous sodium hydroxide solution 9 was added.
8 ml was added. Next, after adding 0.93 ml of concentrated nitric acid, the mixture was cooled to 55 ° C. and stirred for 30 minutes to obtain a fatty acid sodium salt solution.

(Preparation of Preform Emulsion of Fatty Acid Silver and Silver Halide Emulsion A) 15.1 g of the silver halide emulsion A was added to the above fatty acid sodium salt solution, and the pH was adjusted to 8.1 with a sodium hydroxide solution. 147 ml of a 1M silver nitrate solution was added over 7 minutes, and the mixture was further stirred for 20 minutes, and ultra-filtration was performed to remove water-soluble salts. The resulting fatty acid silver particles had an average particle size of 0.8 μm and a monodispersity of 8%. After the floc of the dispersion has formed, the water is removed and an additional 6
After performing water washing and water removal several times, drying was performed to obtain a preform emulsion.

(Preparation of Photosensitive Emulsion) The preform emulsion thus prepared was divided, and a solution of polyvinyl butyral (average molecular weight: 3000) in methyl ethyl ketone (17w) was prepared.
t%) 544 g and toluene 107 g were gradually added and mixed, and then mixed at 280 kgf / cm ² with a media disperser using a 0.5 mm ZrO ₂ bead mill.
The dispersion was performed at 10 ° C. for 10 minutes.

The following layers were simultaneously coated on both sides of the support to prepare a sample.

(Back surface side coating) A liquid having the following composition was coated on layer B-1 of the support.

Cellulose acetate butyrate 15 ml / m ² (10% methyl ethyl ketone solution) Dye-A 7 mg / m ² Dye-B 7 mg / m ² Matting agent: monodispersity 15% Average particle size 8 μm monodisperse silica 90 mg / m ² _{C 8 F 17 (CH 2 CH} 2 O) 12 C 8 F 17 50mg / m 2 C 9 F 17 -C 6 H 4 -SO 3 Na 10mg / m 2

[0230]

Embedded image

(Coating on Photosensitive Layer Surface Side) Photosensitive layer 1: A solution having the following composition was coated on layer A-1 of the support so that the coated silver amount was 2.4 g / m ² .

Photosensitive emulsion 240 g Sensitizing dye (0.1% methanol solution) 1.7 ml Pyridinium bromide perbromide (6% methanol solution) 3 ml Calcium bromide (0.1% methanol solution) 1.7 ml Oxidizing agent ( 10 ml methanol solution) 1.2 ml 2-4-chlorobenzoylbenzoic acid (12% methanol solution) 9.2 ml 2-mercaptobenzimidazole (1% methanol solution) 11 ml tribromomethylsulfoquinoline (5% methanol solution) 17 ml Agents Hardening accelerator P-51 0.3 g shown in Table 1 Phthalazine 0.6 g 4-Methylphthalic acid 0.25 g Tetrachlorophthalic acid 0.2 g Calcium carbonate with an average particle size of 3 μm 0.1 g Developer A-4 ( 20% methanol solution) 20.5 ml Isocyanate compound 0.5 g (Desmodur N3300, manufactured by Mobay Corporation)

[0233]

Embedded image

Surface protective layer: A solution having the following composition was coated simultaneously on the photosensitive layer.

[0235] Acetone 5 ml / m ² methyl ethyl ketone 21 ml / m ² Cellulose acetate butyrate 2.3 g / m ² methanol 7 ml / m ² phthalazine 250 mg / m ² developer A-4 (20% methanol solution) 10 ml / m ² Matting agent : Monodispersity 10% average particle size 4 μm monodisperse silica 5 mg / m ² CH ₂ ＣＨCHSO ₂ CH ₂ CH ₂ OCH ₂ CH ₂ SO ₂ CH = CH ₂ 35 mg / m ² fluorinated surfactant C ₁₂ F ₂₅ ( CH ₂ CH ₂ O) ₁₀ C ₁₂ F ₂₅ 10 mg / m ² C ₈ F ₁₇ —C ₆ H ₄ —SO ₃ Na 10 mg / m ^{2 For} drying, a nozzle is provided in a drying box with a 1 m ³ exhaust duct. 5 nozzles / m ² from top, nozzle pressure 8m
It was set to mAq, the air volume, temperature, and time were changed as shown in the table, drying was performed under drying condition A, and then the coated sample was dried under drying condition B.

(Drying condition A): Drying temperature 50 to 95 ° C.
Nozzle position 250 mm, air volume 20 m ³ / min (drying condition B): drying temperature 50 to 95 ° C., nozzle position 5
0 mm, air flow 200 m ³ / min. The order of drying was first performed when there was a backing layer, and then the emulsion layer side (photosensitive layer, multilayer coating of the photosensitive layer and the protective layer) was performed.

The smoother value of the surface on the photosensitive layer side is 25 m.
mHg, and the smoother value of the surface on the backing layer side was 200 mmHg. The smoother value was measured by keeping the sample unexposed and humidifying at 23 ° C. and 48% RH for 2 hours, and measuring the smoother value of the surface on the photosensitive layer side in the same environment by using a SM-produced by Toyo Denshi Kogyo KK. 6B.

Using the sample after forming the coating film, removing the binder, and observing with an electron microscope by a replica method, the organic silver particles were found to have a major axis diameter of 0.5 ± 0.05 μm.
m, tabular grains having a minor axis diameter of 0.4 ± 0.05 μm and a thickness of 0.01 μm are monodispersity of 5%, which is 90% of all organic silver grains.
Particles.

A sample was prepared by cutting the photothermographic material prepared as described above into a 30 cm width and 50 m length in a dark room.

<< Exposure and development treatment >>
Using a Dotex 2dry manufactured by Scitex, which is an image setter equipped with an 80 nm semiconductor laser, 3
Halftone dots were exposed so as to change the exposure amount in 5% steps at 00 lines, and heat development was performed at 120 ° C. for 25 seconds. At that time, exposure and development were performed in a room conditioned at 23 ° C. and 50% RH.

<< Evaluation of High Contrast >> Halftone dots of 5% of the exposed and heat-developed ones were visually observed with a 100-fold loupe for the dot image quality. We scored 5 without any fringes and dropped ranks as the fringes came out. Less than three ranks are not practical.

<< Evaluation of Sensitivity >> Comparative sample no. The relative value of the amount of light when the amount of light at which the solid exposure (full surface exposure) density of No. 1 is 4 is set to 100 is shown.

<< Evaluation of Fog >> The density of the unexposed portion after the heat development was measured by a Cobbes densitometer. 0.3 or less is preferable.

<< Evaluation of Raw Preservability >> The backing layer was brought into contact with the emulsion layer side and stored at 40 ° C., 55% RH for 3 days using a thermo machine to evaluate.

<< Measurement of Organic Solvent Content in Film >> 46.3 cm ² was cut out as a film area,
It was finely chopped to about mm, stored in a special vial, sealed with a septum and an aluminum cap, and then set in a Hewlett-Packard headspace sampler model HP7694. A gas chromatography (GC: Model 5971 manufactured by Hewlett-Packard) connected to a headspace sampler was equipped with a flame ionization detector (FID) as a detector. The measurement conditions are shown below.

Headspace sampler heating condition: 120 ° C, 20 minutes GC introduction temperature: 150 ° C Column: DB-624 manufactured by J & W Increasing temperature: 45 ° C, hold for 3 minutes → 100 ° C (8 ° C / min) Measurement described above Under the conditions, a gas chromatogram was obtained.
As the solvent to be measured, MEK and methanol were used, and a fixed amount diluted with each of butanol in the solvent on the left was stored in a dedicated vial, and the peak area of the chromatogram obtained by the same measurement as above was used. The solvent content in the film was calculated using the prepared calibration curve.

<< Evaluation of Density Change after Thermal Development >> The sample subjected to the exposure and thermal development was divided into two parts, and one of them was put into a thermo machine at 50 ° C. and 60% RH for five days as an evaluation for the age. The density was measured using a densitometer to determine how much the density changed from 2.5 before the thermometer was injected to the thermometer.

The results are shown in Table 1.

[0249]

[Table 1]

From Table 1, it is clear that the sample of the present invention has higher sensitivity, higher contrast and less fog than the comparative sample.

Example 2 After the back layer (BC) surface was coated and dried, the photosensitive layer and the protective layer were then coated and dried, and the amount of residual solvent in the back layer was adjusted as shown in Table 2. , Sample N of Example 1
o. Samples shown in Table 2 were produced in the same manner as in the production of Sample No. 9.

[0252]

[Table 2]

From Table 2, it is clear that Sample 21 having a high residual solvent amount in the back layer has high fog and insufficient contrast.

Example 3 A sample 2 was prepared in the same manner as the sample 16 in Table 1 of Example 1 except that the drying conditions A and B were changed as shown in Table 3.
7 to 30 were produced.

Each sample was processed and evaluated in the same manner as in Example 1. Table 3 shows the obtained results. The drying unevenness was visually evaluated as follows.

<< Evaluation of Drying Unevenness >> X: Drying unevenness occurs on one side and cannot be used practically. ：: No drying unevenness, suitable for practical use.

[0257]

[Table 3]

From Table 3, it can be seen that Sample 27 was 200
It can be seen that since drying was performed under the drying condition B under air flow conditions as high as m ³ / min, uneven drying occurred, fog was high, and the high contrast rank was low.

[0259]

According to the present invention, a photothermographic material having high sensitivity, high contrast and little fog can be provided.

Claims (3)

[Claims] 1. A photothermographic material comprising an organic silver, a photosensitive silver halide, a reducing agent and a high contrast agent on a support, wherein the photosensitive material contains a solvent in an amount of 10 to 150 mg / m ^2. Characteristic photothermographic material. 2. A photothermographic material containing an organic silver, a photosensitive silver halide, a reducing agent and a high contrast agent on a support, wherein the amount of the solvent on the photosensitive layer side of the support is 10 to 150 m.
g / m ² , and the amount of the solvent in the back layer coated on the support opposite to the photosensitive layer with the support interposed therebetween is not more than 50 mg / m ^2. Characteristic photothermographic material. 3. The photothermographic material according to claim 1, wherein the high contrast agent is represented by the following general formula [H]. Embedded image Wherein A ₀ is an aliphatic group, an aromatic group, a heterocyclic group or-
Represents a G ₀ -D ₀ group, B ₀ represents a blocking group, A ₁ ,
A ₂ represents a hydrogen atom or one of them represents a hydrogen atom and the other represents an acyl group, a sulfonyl group or an oxalyl group. Here, G ₀ is a —CO— group, a —COCO— group, a —CS— group,
—C (＝ NG ₁ D ₁ ) —, —SO—, —SO ₂ — or —P (O) (G ₁ D ₁ ) —, wherein G ₁ is a bond,
-O- group, -S- group, or -N (D ₁₎ - represents a group, D ₁
Represents an aliphatic group, an aromatic group, a heterocyclic group or a hydrogen atom, and when a plurality of D ₁ are present in the molecule, they may be the same or different. D ₀ is a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, an amino group, an alkoxyl group,
Represents an aryloxy group, an alkylthio group or an arylthio group. ]