Photothermographic material Number:6,800,430 from the United States Patent and Trademark Office (PTO) owispatent

Title: Photothermographic material

Abstract: A photothermographic material comprising a photosensitive silver halide, a reducible silver salt, a phenolic reducing agent, a binder and a compound represented by the following formula on the same surface of a support: ##STR1##wherein X.sup.1 is a substituent, X.sup.2 to X.sup.4 are a hydrogen atom or a substituent, and R.sup.1 is an alkyl group etc. The photothermographic material shows high sensitivity, high Dmax and low fog and can provide images suitable for use in photomechanical process.

Patent Number: 6,800,430 Issued on 10/05/2004 to Kyota,   et al.

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Inventors:	Kyota; Hirokazu (Minami-ashigara, JP), Ezoe; Toshihide (Minami-ashigara, JP), Sakai; Minoru (Minami-ashigara, JP), Oya; Toyohisa (Minami-ashigara, JP)
Assignee:	Fuji Photo Film Co., Ltd. (Kanagawa, JP)
Appl. No.:	10/108,728
Filed:	March 29, 2002

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Foreign Application Priority Data

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Mar 29, 2001 [JP]			2001-096643

Current U.S. Class:	430/619 ; 430/264; 430/523; 430/598
Current International Class:	G03C 1/498 (20060101)
Field of Search:	430/619,264,598,566,523

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References Cited [Referenced By]

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U.S. Patent Documents

	6413712		July 2002		Yoshioka et al.
	2001/0051319		December 2001		Oya et al.

Foreign Patent Documents

	2000267222		Sep., 2000		JP
	2001-264929		Sep., 2001		JP

Primary Examiner: Chea; Thorl
Attorney, Agent or Firm: Birch, Stewart, Kolasch & Birch, LLP

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Claims

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What is claimed is:

1. A photothermographic material comprising (a) a photosensitive silver halide, (b) a reducible silver salt of an organic acid, (c) a reducing agent represented by the following formula (1), (d) a binder, (e) a compound represented by the following formula (2), and (f) a nucleating agent on the same surface of a support: ##STR38##

wherein V.sup.1 to V.sup.8 each independently represent a hydrogen atom or a substituent, and L represents a bridging group consisting of --CH(V.sup.9)-- or --S--where V.sup.9 represents a hydrogen atom or a substituent; ##STR39##

wherein X.sup.1 represents a substituent, X.sup.2 to X.sup.4 each independently represent a hydrogen atom or a substituent, provided that X.sup.1 to X.sup.4 do not represent a hydroxy group and X.sup.3 does not represent a sulfonamido group, the substituents represented by X.sup.1 to X.sup.4 optionally bonding to each other to form a ring, and R.sup.1 represents a hydrogen atom, an alkyl group having 1-7 carbon atoms, an aryl group, a heterocyclic group, an amino group or an alkoxy group.

2. The photothermographic material according to claim 1, wherein, in the formula (2), R.sup.1 represents an aryl group or an alkyl group having 1-7 carbon atoms.

3. The photothermographic material according to claim 1, wherein, in the formula (2), at least one of X.sup.1 and X.sup.3 represents an electron-withdrawing group, and R.sup.1 represents an aryl group or an alkyl group having 1-7 carbon atoms.

4. The photothermographic material according to claim 1, wherein, in the formula (2), both of X.sup.1 and X.sup.3 represent a halogen atom, and R.sup.1 represents an aryl group or an alkyl group having 1-7 carbon atoms.

5. The photothermographic material according to claim 1, wherein, in the formula (2), at least one of X.sup.1 and X.sup.3 represents a halogen atom, X.sup.2 and X.sup.4 represent a hydrogen atom or an alkyl group and R.sup.1 represents an aryl group or an alkyl group having 1-7 carbon atoms.

6. The photothermographic material according to claim 1, wherein, in the formula (2), both of X.sup.1 and X.sup.3 represent a chlorine atom or a bromine atom, X.sup.2 and X.sup.4 represent a hydrogen atom or an alkyl group, and R.sup.1 represents an aryl group.

7. The photothermographic material according to claim 1, wherein, in the formula (2), both of X.sup.1 and X.sup.3 represent a chlorine atom or bromine atom, X.sup.2 represents a hydrogen atom or an alkyl group, X.sup.4 represents a hydrogen atom and R.sup.1 represents an aryl group.

8. The photothermographic material according to claim 1, wherein the compound represented by the formula (2) has a total molecular weight in the range of 170-800.

9. The photothermographic material according to claim 1, wherein the compound represented by the formula (2) has a total molecular weight in the range of 220-600.

10. The photothermographic material according to claim 1, wherein the compound represented by the formula (2) has a total molecular weight in the range of 220-500.

11. The photothermographic material according to claim 1, wherein the content of the compound represented by the formula (2) is 0.001-4.0 g per 1 m.sup.2 of the photothermographic material.

12. The photothermographic material according to claim 1, wherein the content of the compound represented by the formula (2) is 0.01-2.0 g per 1 m.sup.2 of the photothermographic material.

13. The photothermographic material according to claim 1, wherein the content of the compound represented by the formula (2) is 0.1-2.0 g per 1 m.sup.2 of the photothermographic material.

14. The photothermographic material according to claim 1, wherein the content of the compound represented by the formula (2) is 0.1-1000 mole % with respect to the content of the compound represented by the formula (1).

15. The photothermographic material according to claim 1, wherein the content of the compound represented by the formula (2) is 1-100 mole % with respect to the content of the compound represented by the formula (1).

16. The photothermographic material according to claim 1, wherein the content of the compound represented by the formula (2) is 5-50 mole % with respect to the content of the compound represented by the formula (1).

17. The photothermographic material according to claim 1, which contains two or more of the compounds represented by the formula (2).

18. The photothermographic material according to claim 1, wherein the compounds represented by the formula (2) is contained in a layer containing silver halide or a layer adjacent thereto.

19. The photothermographic material according to claim 1, which has an undercoat layer containing gelatin between the support and the photosensitive layer.

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Description

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BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a photothermographic material. In particular, the present invention relates to a photothermographic material for scanners, image setters and so forth, which is suitable for photomechanical process. More precisely, the present invention relates to a photothermographic material for photomechanical process that shows high sensitivity, high Dmax (maximum density) and low fog and can provide images suitable for use in photomechanical process.

2. Description of the Related Art

There are known many photosensitive materials having a photosensitive layer on a support, with which image formation is attained by light-exposing imagewise. Those materials include those utilizing a technique of forming images by heat treatment as systems that can contribute to the environmental protection and simplify image-forming means.

In recent years, reduction of amount of waste processing solutions is strongly desired in the field of photomechanical process from the standpoints of environmental protection and space saving. Therefore, development of techniques relating to photothermographic materials for use in photomechanical process is required, which materials enable efficient exposure by a laser scanner or laser image setter and formation of clear black images having high resolution and sharpness. Such photothermographic materials can provide users with simpler and non-polluting heat development processing systems that eliminate the use of solution-type processing chemicals.

Methods for forming images by heat development are described in, for example, U.S. Pat. Nos. 3,152,904 and 3,457,075 and D. Morgan and B. Shely, "Thermally Processed Silver Systems A", Imaging Processes and Materials, Neblette, 8th ed., compiled by J. Sturge, V. Walworth and A. Shepp, p.2 (1969). Such photothermographic materials comprise a reducible non-photosensitive silver salt (e.g., silver salt of an organic acid), a photocatalyst (e.g., silver halide) in a catalytically active amount and a reducing agent for silver, which are usually dispersed in an organic binder matrix. While the photosensitive materials are stable at an ordinary temperature, when they are heated to a high temperature (e.g., 80.degree. C. or higher) after light exposure, silver is produced through an oxidation-reduction reaction between the reducible silver salt (which functions as an oxidizing agent) and the reducing agent. The oxidation-reduction reaction is accelerated by catalytic action of a latent image generated upon exposure. The silver produced from the reaction of the reducible silver salt in the exposed areas shows black color and provides contrast with respect to the non-exposed areas, and thus images are formed.

European Patent Publication (hereinafter referred to as EP-A) 762,196, Japanese Patent Laid-open Publication (Kokai, hereinafter referred to as JP-A) 9-90550 and so forth disclose that high-contrast photographic property can be obtained by incorporating Group VII or VIII metal ions or metal complex ions of such a metal into photosensitive silver halide grains for use in photothermographic materials, or incorporating a hydrazine derivative into the photosensitive materials. Further, U.S. Pat. No. 5,545,515 discloses use of hindered phenols as a reducing agent and use of acrylonitrile compounds as a nucleating agent (ultrahigh contrast agent).

Furthermore, there are also already reported examples of use of phenol compounds as a reducing agent, which compounds have an amino group substituted with an electron-withdrawing group as a substituent (e.g., sulfonamidophenol compounds). For example, as described in JP-A-49-80386, JP-A-5-257227 and JP-A-10-221806, there are known methods of individually utilizing 2,6-dichloro-4-benzenesulfonamidophenol, p-benzenesulfonamidophenol and so forth as a reducing agent. However, even use of these compounds cannot improve sensitivity and cannot solve the problems concerning change of photographic performance (in particular, fog) during storage of photosensitive materials. Meanwhile, there is also known a method of using an aminophenol derivative together with a reducing agent as reported in JP-A-2000-267222. However, it does not satisfy the requirements of high Dmax (maximum density), low fog and high contrast. Accordingly, it has been desired to provide a photothermographic material for photomechanical process that shows high sensitivity, high Dmax (maximum density) and low fog and can provide images suitable for use in photomechanical process.

SUMMARY OF THE INVENTION

The objects of the present invention are to solve the aforementioned problems of the prior art. That is, a first object to be achieved by the present invention is to provide a photothermographic material that shows high sensitivity, high Dmax (maximum density) and low fog, and can provide images suitable for photomechanical process, in particular, as a photothermographic material for photomechanical process, more specifically, a photothermographic material for scanners, image setters and so forth. A second object to be achieved by the present invention is to provide a photothermographic material that can be prepared by coating of an aqueous system, which is advantageous for environment and cost.

The inventors of the present invention assiduously studied in order to achieve the aforementioned objects. As a result, they found that an excellent photothermographic material that provided the desired effects could be obtained by using a particular bisphenol compound and a particular phenol compound in combination in an image-forming layer, and thus accomplished the present invention.

That is, the present invention provides a photothermographic material comprising (a) a photosensitive silver halide, (b) a reducible silver salt, (c) a reducing agent represented by the following formula (1), (d) a binder and (e) a compound represented by the following formula (2) on the same surface of a support. ##STR2##

In the formula (1), V.sup.1 to V.sup.8 each independently represent a hydrogen atom or a substituent, and L represents a bridging group consisting of --CH(V.sup.9)-- or --S-- where V.sup.9 represents a hydrogen atom or a substituent. ##STR3##

In the formula (2), X.sup.1 represents a substituent, and X.sup.2 to X.sup.4 each independently represent a hydrogen atom or a substituent, provided that X.sup.1 to X.sup.4 do not represent hydroxy group and X.sup.3 does not represent a sulfonamido group. The substituents represented by X.sup.1 to X.sup.4 may bond to each other to form a ring. R.sup.1 represents a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, an amino group or an alkoxy group.

Preferably, in the formula (2), R.sup.1 represents a hydrogen atom, an aryl group, a heterocyclic group, an amino group, an alkoxy group or an alkyl group having 1-7 carbon atoms. More preferably, in the formula (2), at least one of X.sup.1 and X.sup.3 is an electron-withdrawing group, and R.sup.1 is an aryl group or an alkyl group having 1-7 carbon atoms. Still more preferably, in the formula (2), both of X.sup.1 and X.sup.3 represent a halogen atom, and R.sup.1 represents an aryl group or an alkyl group having 1-7 carbon atoms. Most preferably, in the formula (2), both of X.sup.1 and X.sup.3 represent a chlorine atom or a bromine atom, X.sup.2 and X.sup.4 represent a hydrogen atom or an alkyl group, and R.sup.1 represents an aryl group.

Preferably, the photothermographic material of the present invention further contains a nucleating agent (ultrahigh contrast agent). Further, it is preferably has an undercoat layer containing gelatin between the support and the photosensitive layer.

The photothermographic material of the present invention provides high Dmax (maximum density), high contrast and low fog, in the presence of a nucleating agent and thus it has photographic properties suitable for use in photomechanical process. It also provides good photographic properties of high Dmax and low fog, even if it does not contain a nucleating agent.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a side view of an exemplary heat development apparatus used for heat development of the photothermographic material of the present invention. In the FIGURE, there are shown a photothermographic material 10, carrying-in roller pairs 11, carrying-out roller pairs 12, rollers 13, a flat surface 14, heaters 15, and guide panels 16. The apparatus consists of a preheating section A, a heat development section B, and a gradual cooling section C.

PREFERRED EMBODIMENTS OF THE INVENTION

The photothermographic material of the present invention will be explained in detail hereafter. In the present specification, ranges indicated with "-" mean ranges including the numerical values before and after "-" as the minimum and maximum values.

The photothermographic material of the present invention comprises (a) a photosensitive silver halide, (b) a reducible silver salt and (d) a binder on the same surface of a support. The photothermographic material of the present invention may be one having an image-forming layer containing a reducible silver salt (silver salt of an organic acid) and binder and a photosensitive silver halide emulsion layer (photosensitive layer) containing a photosensitive silver halide as separate layers or one having a photosensitive image-forming layer containing the reducible silver salt (silver salt of an organic acid), photosensitive silver halide and binder all together. Preferred is the latter one.

The photothermographic material of the present invention is characterized by further containing, in addition to the aforementioned three types of components, both of (c) a reducing agent represented by the aforementioned formula (1) and (e) a compound represented by the aforementioned formula (2). This characteristic makes it possible to provide a photothermographic material that shows high sensitivity, high Dmax (maximum density) and low fog and can provide images suitable for photomechanical process.

The photothermographic material of the present invention comprises a bisphenol compound represented by the aforementioned formula (1) on the same surface of a support as the photosensitive silver halide and the reducible silver salt.

In the formula (1), V.sup.1 to V.sup.8 each independently represent a hydrogen atom or a substituent. The substituents represented by V.sup.1 to V.sup.8 may be the same or different from one another. Preferred examples of the substituents include a halogen atom (e.g., fluorine atom, chlorine atom, bromine atom and iodine atom), a linear, branched or cyclic alkyl group having preferably 1-20 carbon atoms, more preferably 1-16 carbon atoms, further preferably 1-13 carbon atoms (e.g., methyl group, ethyl group, n-propyl group, isopropyl group, sec-butyl group, tert-butyl group, tert-octyl group, n-amyl group, tert-amyl group, n-dodecyl group, n-tridecy group, cyclohexyl group etc.) an alkenyl group having preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, further preferably 2-12 carbon atoms (e.g., vinyl group, allyl group, 2-butenyl group, 3-pentenyl group etc.), an aryl group having preferably 6-30 carbon atoms, more preferably 6-20 carbon atoms, further preferably 6-12 carbon atoms (e.g., phenyl group, p-methylphenyl group, naphthyl group etc.), an alkoxy group having preferably 1-20 carbon atoms, more preferably 1-16 carbon atoms, further preferably 1-12 carbon atoms (e.g., methoxy group, ethoxy group, propoxy group, butoxy group etc.) an aryloxy group having preferably 6-30 carbon atoms, more preferably 6-20 carbon atoms, further preferably 6-12 carbon atoms (e.g., phenyloxy group, 2-naphthyloxy group etc.), an acyloxy group having preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, further preferably 2-12 carbon atoms (e.g., acetoxy group, benzoyloxy group etc.), an amino group having preferably 0-20 carbon atoms, more preferably 1-16 carbon atoms, further preferably 1-12 carbon atoms (e.g., dimethylamino group, diethylamino group, dibutylamino group, anilino group etc.), an acylamino group having preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, further preferably 2-13 carbon atoms (e.g., acetylamino group, tridecanoylamino group, benzoylamino group etc.), a sulfonylamino group having preferably 1-20 carbon atoms, more preferably 1-16 carbon atoms, further preferably 1-12 carbon atoms (e.g., methanesulfonylamino group, butanesulfonylamino group, benzenesulfonylamino group etc.), a ureido group having preferably 1-20 carbon atoms, more preferably 1-16 carbon atoms, further preferably 1-12 carbon atoms (e.g., ureido group, methylureido group, phenylureido group etc.), a carbamate group having preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, further preferably 2-12 carbon atoms (e.g., methoxycarbonylamino group, phenyloxycarbonylamino group etc.), a carboxyl group, a carbamoyl group having preferably 1-20 carbon atoms, more preferably 1-16 carbon atoms, further preferably 1-12 carbon atoms (e.g., carbamoyl group, N,N-diethylcarbamoyl group, N-dodecylcarbamoyl group, N-phenylcarbamoyl group etc.), an alkoxycarbonyl group having preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, further preferably 2-12 carbon atoms (e.g., methoxycarbonyl group, ethoxycarbonyl group, butoxycarbonyl group etc.), an aryloxycarbonyl group having preferably 6-20 carbon atoms, more preferably 6-16 carbon atoms, further preferably 6-12 carbon atoms, an acyl group having preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, further preferably 2-12 carbon atoms (e.g., acetyl group, benzoyl group, formyl group, pivaloyl group etc.), a sulfo group, a sulfonyl group having preferably 1-20 carbon atoms, more preferably 1-16 carbon atoms, further preferably 1-12 carbon atoms (e.g., mesyl group, tosyl group etc.), a sulfamoyl group having preferably 0-20 carbon atoms, more preferably 0-16 carbon atoms, further preferably 0-12 carbon atoms (e.g., sulfamoyl group, methylsulfamoyl group, dimethylsulfamoyl group, phenylsulfamoyl group, etc.), a cyano group, a nitro group, a mercapto group, an alkylthio group having preferably 1-20 carbon atoms, more preferably 1-16 carbon atoms, further preferably 1-12 carbon atoms (e.g., methylthio group, butylthio group etc.), a heterocyclic group having preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, further preferably 2-12 carbon atoms (e.g., pyridyl group, imidazoyl group, pyrrolidyl group etc.) and so forth. These substituents may be further substituted with other substituents.

Particularly preferred examples of the substituents represented by V.sup.1 to V.sup.8 are alkyl groups (for example, methyl group, ethyl group, n-propyl group, isopropyl group, sec-butyl group, tert-butyl group, tert-octyl group, n-amyl group, tert-amyl group, n-dodecyl group, n-tridecyl group, cyclohexyl group etc.).

In the formula (1), L represents a bridging group consisting of --CH(V.sup.9)-- or --S--, and V.sup.9 represents a hydrogen atom or a substituent. Preferred examples of the substituent represented by V.sup.9 include a halogen atom (e.g., fluorine atom, chlorine atom, bromine atom and iodine atom), a linear, branched or cyclic alkyl group having preferably 1-20 carbon atoms, more preferably 1-16 carbon atoms, further preferably 1-13 carbon atoms (e.g., methyl group, ethyl group, n-propyl group, isopropyl group, sec-butyl group, tert-butyl group, tert-octyl group, n-amyl group, tert-amyl group, n-dodecyl group, n-tridecyl group, cyclohexyl group, 2,4,4-trimethylpentyl group etc.), an alkenyl group having preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, further preferably 2-12 carbon atoms (e.g., vinyl group, allyl group, 2-butenyl group, 3-pentenyl group etc.), an aryl group having preferably 6-30 carbon atoms, more preferably 6-20 carbon atoms, further preferably 6-12 carbon atoms (e.g., phenyl group, p-methylphenyl group, naphthyl group etc.), an alkoxy group having preferably 1-20 carbon atoms, more preferably 1-16 carbon atoms, further preferably 1-12 carbon atoms (e.g., methoxy group, ethoxy group, propoxy group, butoxy group etc.), an aryloxy group having preferably 6-30 carbon atoms, more preferably 6-20 carbon atoms, further preferably 6-12 carbon atoms (e.g., phenyloxy group, 2-naphthyloxy group etc.), an acyloxy group having preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, further preferably 2-12 carbon atoms (e.g., acetoxy group, benzoyloxy group etc.), an amino group having preferably 0-20 carbon atoms, more preferably 1-16 carbon atoms, further preferably 1-12 carbon atoms (e.g., dimethylamino group, diethylamino group, dibutylamino group, anilino group etc.), an acylamino group having preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, particularly preferably 2-13 carbon atoms (e.g., acetylamino group, tridecanoylamino group, benzoylamino group etc.), a sulfonylamino group having preferably 1-20 carbon atoms, more preferably 1-16 carbon atoms, further preferably 1-12 carbon atoms (e.g., methanesulfonylamino group, butanesulfonylamino group, benzenesulfonylamino group etc.), a ureido group having preferably 1-20 carbon atoms, more preferably 1-16 carbon atoms, further preferably 1-12 carbon atoms (e.g., ureido group, methylureido group, phenylureido group etc.), a carbamate group having preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, further preferably 2-12 carbon atoms (e.g., methoxycarbonylamino group, phenyloxycarbonylamino group etc.), a carboxyl group, a carbamoyl group having preferably 1-20 carbon atoms, more preferably 1-16 carbon atoms, further preferably 1-12 carbon atoms (e.g., carbamoyl group, N,N-diethylcarbamoyl group, N-dodecylcarbamoyl group, N-phenylcarbamoyl group etc.), an alkoxycarbonyl group having preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, further preferably 2-12 carbon atoms (e.g., methoxycarbonyl group, ethoxycarbonyl group, butoxycarbonyl group etc.), an acyl group having preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, further preferably 2-12 carbon atoms (e.g., acetyl group, benzoyl group, formyl group, pivaloyl group etc.), a sulfo group, a sulfonyl group having preferably 1-20 carbon atoms, more preferably 1-16 carbon atoms, further preferably 1-12 carbon atoms (e.g., mesyl group, tosyl group etc.), a sulfamoyl group having preferably 0-20 carbon atoms, more preferably 0-16 carbon atoms, further preferably 0-12 carbon atoms (e.g., sulfamoyl group, methylsulfamoyl group, dimethylsulfamoyl group, phenylsulfamoyl group etc.), a cyano group, a nitro group, a hydroxyl group, a mercapto group, an alkylthio group having preferably 1-20 carbon atoms, more preferably 1-16 carbon atoms, further preferably 1-12 carbon atoms (e.g., methylthio group, butylthio group etc.), a heterocyclic group having preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, further preferably 2-12 carbon atoms (e.g., pyridyl group, imidazoyl group, pyrrolidyl group etc.) and so forth. These substituents may be further substituted with other substituents.

Particularly preferred examples of the substituent represented by V.sup.9 are an alkyl group (e.g., methyl group, ethyl group, n-propyl group, isopropyl group, sec-butyl group, tert-butyl group, tert-octyl group, n-amyl group, n-octyl group, tert-amyl group, n-dodecyl group, n-tridecyl group, cyclohexyl group, 2,4,4-trimethylpentyl group etc.), an alkenyl group (e.g., vinyl group, allyl group, 2-butenyl group, 3-pentenyl group etc.), an aryl group (e.g., phenyl group, p-methylphenyl group, naphthyl group etc.), a hydroxyl group, a mercapto group, an alkylthio group (e.g., methylthio group, butylthio group etc.) and so forth.

Specific examples of the bisphenol compound represented by the formula (1) will be shown below. However, the bisphenol compound used for the present invention is not limited to these examples. ##STR4## ##STR5## ##STR6## ##STR7## ##STR8## ##STR9##

The compound represented by the formula (1) can be easily synthesized by a usual method for condensing an aldehyde (sulfur dichloride for the cases of I-25 and I-26) and a phenol.

The amount of the bisphenol compound represented by the formula (1) is preferably 0.01-4.0 g, more preferably 0.2-2.0 g, further preferably 0.5-2.0 g, per 1 m.sup.2 of the photothermographic material. Further, it is preferably contained in an amount of 2-40 moles, more preferably 5-30 moles, per mole of silver present on the surface having the image-forming layer.

The bisphenol compound used in the present invention may be added in any form, for example, as a solution, powder, solid microparticle dispersion and so forth. The solid microparticle dispersion can be formed by a known pulverization means (for example, a ball mill, vibration ball mill, sand mill, colloid mill, jet mill, roller mill etc.). Further, when solid microparticle dispersion is prepared, a dispersing aid may be used.

The bisphenol compound used in the present invention may be added to any layer provided on the same side on a support as the aforementioned photosensitive silver halide and reducible silver salt. However, it is preferably added to a layer containing the silver halide or a layer adjacent thereto.

The photothermographic material of the present invention comprises a phenol compound represented by the aforementioned formula (2) on the same surface of a support as the aforementioned photosensitive silver halide and reducible silver salt.

In the formula (2), X.sup.1 represents a substituent that can substitute on the benzene ring (it is not a hydrogen atom). However, X.sup.1 does not represent a hydroxy group. Examples of the substituent include, for example, a halogen atom, an alkyl group (including a cycloalkyl group and a bicycloalkyl group), an alkenyl group (including a cycloalkenyl group and a bicycloalkenyl group), an alkynyl group, an aryl group, a heterocyclic group, a cyano group, a nitro group, a carboxyl group, an alkoxy group, an aryloxy group, a silyloxy group, a heterocyclyloxy group, an acyloxy group, a carbamoyloxy group, an alkoxycarbonyloxy group, an aryloxycarbonyloxy, an acylamino group, an aminocarbonylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfamoylamino group, an alkyl- or arylsulfonylamino group, a mercapto group, an alkylthio group, an arylthio group, a heterocyclylthio group, a sulfamoyl group, a sulfo group, an alkyl- or arylsulfinyl group, an alkyl- or arylsulfonyl group, an acyl group, an aryloxycarbonyl group, an alkoxycarbonyl group, a carbamoyl group, an aryl- or heterocyclylazo group, an imido group, a phosphino group, a phosphinyl group, a phosphinyloxy group, a phosphinylamino group, a silyl group and so forth.

More specifically, the followings can be mentioned as examples of the substituent: a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), an alkyl group [a linear, branched or cyclic substituted or unsubstituted alkyl group including an alkyl group (preferably an alkyl group having 1-30 carbon atoms, e.g., methyl group, ethyl group, n-propyl group, isopropyl group, tert-butyl group, n-octyl group, eicosyl group, 2-chloroethyl group, 2-cyanoethyl group and 2-ethylhexyl group), a cycloalkyl group (preferably a substituted or unsubstituted cycloalkyl group having 3-30 carbon atoms, e.g., cyclohexyl group, cyclopentyl group and 4-n-dodecylcyclohexyl group), a bicycloalkyl group (preferably a substituted or unsubstituted bicycloalkyl group having 5-30 carbon atoms, i.e., a monovalent group obtained by removing one hydrogen atom from a bicycloalkane having 5-30 carbon atoms, e.g., bicyclo[1,2,2]heptan-2-yl group and bicyclo[2,2,2]octan-3-yl group), and an alkyl group having a structure containing more rings such as tricyclic structure and so forth, the alkyl groups in the substituents explained below (for example, alkyl group of alkylthio group) also represent such a conception of alkyl group], an alkenyl group [a linear, branched or cyclic substituted or unsubstituted alkenyl group, including an alkenyl group (preferably a substituted or unsubstituted alkenyl group having 2-30 carbon atoms, e.g., vinyl group, allyl group, prenyl group, geranyl group and oleyl group), a cycloalkenyl group (preferably a substituted or unsubstituted cycloalkenyl group having 3-30 carbon atoms, i.e., a monovalent group obtained by removing one hydrogen atom from a cycloalkene having 3-30 carbon atoms, e.g., 2-cyclopenten-1-yl group and 2-cyclohexen-1-yl group), and a bicycloalkenyl group (a substituted or unsubstituted bicycloalkenyl group, preferably a substituted or unsubstituted bicycloalkenyl group having 5-30 carbon atoms, i.e., a monovalent group obtained by removing one hydrogen atom from a bicycloalkene having one double bond, e.g., bicyclo[2,2,1]hept-2-en-1-yl group and bicyclo[2,2,2]oct-2-en-4-yl) group], an alkynyl group (preferably a substituted or unsubstituted alkynyl group having 2-30 carbon atoms, e.g., ethynyl group, propargyl group, trimethylsilylethynyl group etc.), an aryl group (preferably a substituted or unsubstituted aryl group having 6-30 carbon atoms, e.g., phenyl group, p-tolyl group, naphthyl group, m-chlorophenyl group and o-hexadecanoylaminophenyl group), a heterocyclic group (preferably a 5- or 6-membered substituted or unsubstituted monovalent group obtained by removing one hydrogen atom from an aromatic or non-aromatic heterocyclic compound, more preferably 5- or 6-membered aromatic heterocyclic group having 3-30 carbon atoms, e.g., 2-furyl group, 2-thienyl group, 2-pyrimidinyl group and 2-benzothiazolyl group), a cyano group, a nitro group, a carboxyl group, an alkoxy group (preferably a substituted or unsubstituted alkoxy group having 1-30 carbon atoms, e.g., methoxy group, ethoxy group, isopropoxy group, tert-butoxy group, n-octyloxy group and 2-methoxyethoxy group), an aryloxy group (preferably a substituted or unsubstituted aryloxy group having 6-30 carbon atoms, e.g., phenoxy group, 2-methylphenoxy group, 4-tert-butylphenoxy group, 3-nitrophenoxy group and 2-tetradecanoylaminophenoxy group), a silyloxy group (preferably a silyloxy group having 3-20 carbon atoms, e.g., trimethylsilyloxy group and tert-butyldimethylsilyloxy group), a heterocyclyloxy group (preferably a substituted or unsubstituted heterocyclyloxy group having 2-30 carbon atoms, e.g., 1-phenyltetrazol-5-oxy group and 2-tetrahydropyranyloxy group), an acyloxy group (preferably a formyloxy group, a substituted or unsubstituted alkylcarbonyloxy group having 2-30 carbon atoms, a substituted or unsubstituted arylcarbonyloxy group having 6-30 carbon atoms, e.g., formyloxy group, acetyloxy group, pivaloyloxy group, stearoyloxy group, benzoyloxy group and p-methoxyphenyl-carbonyloxy group), a carbamoyloxy group (preferably a substituted or unsubstituted carbamoyloxy group having 1-30 carbon atoms, e.g., N,N-dimethylcarbamoyloxy group, N,N-diethylcarbamoyloxy group, morpholinocarbonyloxy group, N,N-di-n-octylaminocarbonyloxy group and N-n-octylcarbamoyl-oxy group), an alkoxycarbonyloxy group (preferably a substituted or substituted alkoxycarbonyloxy group having 2-30 carbon atoms, e.g., methoxycarbonyloxy group, ethoxycarbonyloxy group, tert-butoxycarbonyloxy group and n-octylcarbonyloxy group), an aryloxycarbonyloxy group (preferably a substituted or unsubstituted aryloxycarbonyloxy group having 7-30 carbon atoms, e.g., phenoxycarbonyloxy group, p-methoxyphenoxycarbonyloxy group and p-n-hexadecyloxyphenoxycarbonyloxy group), an acylamino group (preferably a formylamino group, a substituted or unsubstituted alkylcarbonylamino group having 1-30 carbon atoms or a substituted or unsubstituted arylcarbonylamino group having 6-30 carbon atoms, e.g., formylamino group, acetylamino group, pivaloylamino group, lauroylamino group, benzoylamino group and 3,4,5-tri-n-octyloxyphenylcarbonylamino group), an aminocarbonylamino group (preferably a substituted or unsubstituted aminocarbonylamino group having 1-30 carbon atoms, e.g., carbamoylamino group, N,N-dimethylaminocarbonyl-amino group, N,N-diethylaminocarbonylamino group and morpholinocarbonylamino group), an alkoxycarbonylamino group (preferably a substituted or unsubstituted alkoxycarbonylamino group having 2-30 carbon atoms, e.g., methoxycarbonylamino group, ethoxycarbonylamino group, tert-butoxycarbonylamino group, n-octadecyloxycarbonylamino group and N-methyl-methoxycarbonylamino group), an aryloxycarbonylamino group (preferably a substituted or unsubstituted aryloxycarbonylamino group having 7-30 carbon atoms, e.g., phenoxycarbonylamino group, p-chlorophenoxy-carbonylamino group, m-n-octyloxyphenoxycarbonylamino group) a sulfamoylamino group (preferably a substituted or unsubstituted sulfamoylamino group having 0-30 carbon atoms, e.g., sulfamoylamino group, N,N-dimethylaminosulfonylamino group and N-n-octylaminosulfonylamino group), an alkyl- or arylsulfonylamino group (preferably a substituted or unsubstituted alkylsulfonylamino group having 1-30 carbon atoms or a substituted or unsubstituted arylsulfonylamino group having 6-30 carbon atoms, e.g., methylsulfonylamino group, butylsulfonylamino group, phenylsulfonylamino, 2,3,5-tri-chlorophenylsulfonylamino and p-methylphenylsulfonylamino group), a mercapto group, an alkylthio group (preferably a substituted or unsubstituted alkylthio group having 1-30 carbon atoms, e.g., methylthio group, ethylthio group and n-hexadecylthio group), an arylthio group (preferably a substituted or unsubstituted arylthio group having 6-30 carbon atoms, e.g., phenylthio group, p-chlorophenylthio group and m-methoxyphenylthio group), a heterocyclylthio group (preferably a substituted or unsubstituted heterocyclylthio group having 2-30 carbon atoms, e.g., 2-benzothiazolylthio group and 1-phenyltetrazol-5-ylthio group), a sulfamoyl group (preferably a substituted or unsubstituted sulfamoyl group having 0-30 carbon atoms, e.g., N-ethylsulfamoyl group, N-(3-dodecyloxypropyl) sulfamoyl group, N,N-dimethylsulfamoyl group, N-acetylsulfamoyl group, N-benzoylsulfamoyl group and N-(N'-phenylcarbamoyl)sulfamoyl group), a sulfo group, an alkyl- or arylsulfinyl group (preferably a substituted or unsubstituted alkylsulfinyl group having 1-30 carbon atoms or a substituted or unsubstituted arylsulfinyl group having 6-30 carbon atoms, e.g., methylsulfinyl group, ethylsulfinyl group, phenylsulfinyl group and p-methylphenylsulfinyl group), an alkyl- or arylsulfonyl group (preferably a substituted or unsubstituted alkylsulfonyl group having 1-30 carbon atoms or a substituted or unsubstituted arylsulfonyl group having 6-30 carbon atoms, e.g., methylsulfonyl group, ethylsulfonyl group, phenylsulfonyl group and p-methylphenylsulfonyl group), an acyl group (preferably a formyl group, a substituted or unsubstituted alkylcarbonyl group having 2-30 carbon atoms, a substituted or unsubstituted arylcarbonyl group having 7-30 carbon atoms, a substituted or unsubstituted heterocyclylcarbonyl group having 4-30 carbon atoms, in which a heterocyclic ring is bonded to a carbonyl group at a carbon atom, e.g., acetyl group, pivaloyl group, 2-chloroacetyl group, stearoyl group, benzoyl group, p-n-octyloxyphenylcarbonyl group, 2-pyridylcarbonyl group and 2-furylcarbonyl group), an aryloxycarbonyl group (preferably a substituted or unsubstituted aryloxycarbonyl group having 7-30 carbon atoms, e.g., phenoxycarbonyl group, o-chlorophenoxycarbonyl group, m-nitrophenoxycarbonyl group and p-tert-butylphenoxycarbonyl group), an alkoxycarbonyl group (preferably a substituted or unsubstituted alkoxycarbonyl group having 2-30 carbon atoms, e.g., methoxycarbonyl group, ethoxycarbonyl group, tert-butoxycarbonyl group and n-octadecyloxycarbonyl group), a carbamoyl group (preferably a substituted or unsubstituted carbamoyl group having 1-30 carbon atoms, e.g., carbamoyl group, N-methylcarbamoyl group, N,N-dimethylcarbamoyl group, N,N-di-n-octylcarbamoyl group and N-(methylsulfonyl)carbamoyl group), an aryl- or heterocyclylazo group (preferably a substituted or unsubstituted arylazo group having 6-30 carbon atoms or a substituted or unsubstituted heterocyclylazo group having 3-30 carbon atoms, e.g., phenylazo group, p-chlorophenylazo group and 5-ethylthio-1,3,4-thiadiazol-2-ylazo group), an imido group (preferably N-succinimido group and N-phthalimido group), a phosphino group (preferably a substituted or unsubstituted phosphino group having 2-30 carbon atoms, e.g., dimethylphosphino group, diphenylphosphino group and methylphenoxyphosphino group), a phosphinyl group (preferably a substituted or unsubstituted phosphinyl group having 2-30 carbon atoms, e.g., phosphinyl group, dioctyloxyphosphinyl group and diethoxyphosphinyl group), a phosphinyloxy group (preferably a substituted or unsubstituted phosphinyloxy group having 2-30 carbon atoms, e.g., diphenoxyphosphinyloxy group and dioctyloxyphosphinyloxy group), a phosphinylamino group (preferably a substituted or unsubstituted phosphinylamino group having 2-30 carbon atoms, e.g., dimethoxyphosphinylamino group and dimethylaminophosphinylamino group), and a silyl group (preferably a substituted or unsubstituted silyl group having 3-30 carbon atoms, e.g., trimethylsilyl group, tert-butyldimethylsilyl group and phenyldimethylsilyl group).

Preferred examples of the substituents represented by X.sup.1 include a halogen atom (fluorine atom, chlorine atom, bromine atom and iodine atom, more preferably chlorine atom and bromine atom), an acylamino group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., formylamino group, acetylamino group, benzoylamino group etc.), an alkyl group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., methyl group, ethyl group, isopropyl group, cyclohexyl group etc.), an aryl group having preferably 6-20 carbon atoms, more preferably 6-14 carbon atoms, particularly preferably 6-8 carbon atoms (e.g., phenyl group, naphthyl group, p-methylphenyl group etc.), an alkoxy group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., methoxy group, ethoxy group etc.), an aryloxy group having preferably 6-20 carbon atoms, more preferably 6-14 carbon atoms, particularly preferably 6-8 carbon atoms (e.g., phenyloxy group, 2-naphthyloxy group etc.), an acyloxy group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., acetoxy group, benzoyloxy group etc.), a sulfonylamino group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., methanesulfonylamino group, benzenesulfonylamino group etc.), a carbamoyl group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., carbamoyl group, N,N-diethylcarbamoyl group, N-phenylcarbamoyl group etc.), an acyl group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., formyl group, acetyl group, benzoyl group etc.), an alkoxycarbonyl group having preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, further preferably 2-12 carbon atoms (e.g., methoxycarbonyl group, ethoxycarbonyl group, butoxycarbonyl group etc.), an aryloxycarbonyl group having preferably 6-20 carbon atoms, more preferably 6-16 carbon atoms, further preferably 6-12 carbon atoms (e.g., phenoxycarbonyl group, 2-naphthyloxycarbonyl group etc.), a cyano group and a nitro group. X.sup.1 is more preferably a halogen atom, an acylamino group or an alkyl group, particularly preferably a chlorine atom or bromine atom.

In the formula (2), X.sup.3 represents a hydrogen atom or a substituent. However, X.sup.3 does not represent a hydroxy group or a sulfonamido group. As specific examples of the substituent, those mentioned as examples of X.sup.1 in the formula (2) can be mentioned (except for sulfonamido group). X.sup.3 is preferably a hydrogen atom, a halogen atom (fluorine atom, chlorine atom, bromine atom and iodine atom, more preferably chlorine atom and bromine atom), an acylamino group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., formylamino group, acetylamino group, benzoylamino group etc.), an alkyl group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., methyl group, ethyl group, isopropyl group, cyclohexyl group etc.), an aryl group having preferably 6-20 carbon atoms, more preferably 6-14 carbon atoms, particularly preferably 6-8 carbon atoms (e.g., phenyl group, naphthyl group, p-methylphenyl group etc.), an alkoxy group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., methoxy group, ethoxy group etc.), an aryloxy group having preferably 6-20 carbon atoms, more preferably 6-14 carbon atoms, particularly preferably 6-8 carbon atoms (e.g., phenyloxy group, 2-naphthyloxy group etc.), an acyloxy group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., acetoxy group, benzoyloxy group etc.), a carbamoyl group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., carbamoyl group, N,N-diethylcarbamoyl group, N-phenylcarbamoyl group etc.), an acyl group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., formyl group, acetyl group, benzoyl group etc.), an alkoxycarbonyl group having preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, further preferably 2-12 carbon atoms (e.g., methoxycarbonyl group, ethoxycarbonyl group, butoxycarbonyl group etc.), an aryloxycarbonyl group having preferably 6-20 carbon atoms, more preferably 6-16 carbon atoms, further preferably 6-12 carbon atoms (e.g., phenoxycarbonyl group, 2-naphthyloxycarbonyl group etc.) a cyano group or a nitro group. X.sup.3 is more preferably a halogen atom, an acylamino group or an alkyl group, particularly preferably a chlorine atom or a bromine atom.

It is preferred that at least one of the substituents represented by X.sup.1 and X.sup.3 should be an electron-withdrawing group. The electron withdrawing group is a substituent that gives a positive value of the Hammett's substituent constant .sigma.p, and specific examples thereof include a halogen atom, a cyano group, a nitro group, an alkoxycarbonyl group, an aryloxycarbonyl group, an imino group, an imino group substituted at N atom, a thiocarbonyl group, a perfluoroalkyl group, a sulfonamido grop, a formyl group, a phosphoryl group, a carboxyl group, a carbamoyl group, an acyl group, a sulfo group (or a salt thereof) an alkylsulfonyl group, an arylsulfonyl group, a sulfamoyl group, an acyloxy group, an acylthio group, a sulfonyloxy group, a heterocyclic group, an aryl group substituted with any one of these electron-withdrawing groups and so forth. More preferably, both of X.sup.1 and X.sup.3 represent an electron-withdrawing group, further preferably the both represent a halogen atom, and particularly preferably the both represent a chlorine atom or a bromine atom.

In the formula (2), X.sup.2 and X.sup.4 represent a hydrogen atom or a substituent. However, X.sup.2 and X.sup.4 do not represent a hydroxy group. As specific examples of the substituent, those substituents mentioned as examples of X.sup.1 in the formula (2) can be mentioned. Preferred examples X.sup.2 and X.sup.4 include a halogen atom (fluorine atom, chlorine atom, bromine atom and iodine atom, more preferably chlorine atom and bromine atom), an acylamino group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., formylamino group, acetylamino group, benzoylamino group etc.) an alkyl group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., methyl group, ethyl group, isopropyl group, cyclohexyl group etc.), an aryl group having preferably 6-20 carbon atoms, more preferably 6-14 carbon atoms, particularly preferably 6-8 carbon atoms (e.g., phenyl group, naphthyl group, p-methylphenyl group etc.), an alkoxy group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., methoxy group, ethoxy group etc.), an aryloxy group having preferably 6-20 carbon atoms, more preferably 6-14 carbon atoms, particularly preferably 6-8 carbon atoms (e.g., phenyloxy group, 2-naphthyloxy group etc.), an acyloxy group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., acetoxy group, benzoyloxy group etc.), a sulfonylamino group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., methanesulfonylamino group, benzenesulfonylamino group etc.) a carbamoyl group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., carbamoyl group, N,N-diethylcarbamoyl group, N-phenylcarbamoyl group etc.), an acyl group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., formyl group, acetyl group, benzoyl group etc.), an alkoxycarbonyl group having preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, further preferably 2-12 carbon atoms (e.g., methoxycarbonyl group, ethoxycarbonyl group, butoxycarbonyl group etc.), an aryloxycarbonyl group having preferably 6-20 carbon atoms, more preferably 6-16 carbon atoms, further preferably 6-12 carbon atoms (e.g., phenoxycarbonyl group, 2-naphthyloxycarbonyl group etc.), a cyano group and a nitro group. X.sup.2 and X.sup.4 more preferably represent a hydrogen atom, an alkyl group, an aryl group, a halogen atom or an acylamino group, and they particularly preferably represent a hydrogen atom, methyl group or ethyl group.

X.sup.1 to X.sup.4 may further have a substituent. As specific examples of the substituent, those substituents mentioned as examples of X.sup.1 in the formula (2) can be mentioned. Further, X.sup.1 to X.sup.4 may bond to each other or one another to form a ring.

In the formula (2), R.sup.1 represents a hydrogen atom, an alkyl group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-7 carbon atoms (e.g., methyl group, ethyl group, isopropyl group, cyclohexyl group etc.), an aryl group having preferably 6-20 carbon atoms, more preferably 6-14 carbon atoms, particularly preferably 6-8 carbon atoms (e.g., phenyl group, naphthyl group, p-methylphenyl group etc.), a heterocyclic group (e.g., pyridyl group, imidazoyl group, pyrrolidyl group etc.), an amino group having preferably 0-20 carbon atoms, more preferably 0-14 carbon atoms, particularly preferably 0-8 carbon atoms (e.g., amino group, methylamino group, N,N-dimethylamino group, N-phenylamino group etc.), or an alkoxy group having preferably 1-20 carbon atoms, more preferably 1-14 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., methoxy group, ethoxy group etc.). R.sup.1 preferably represents a hydrogen atom, an aryl group, a heterocyclic group, an amino group, an alkoxy group or an alkyl group having 1-7 carbon atoms, further preferably an aryl group or an alkyl group having 1-7 carbon atoms, particularly preferably an aryl group. R.sup.1 may further have a substituent. As specific examples of the substituent, those substituents mentioned as examples of X.sup.1 in the formula (2) can be mentioned.

In a preferred combination of X.sup.1 to X.sup.4 and R.sup.1, at least one of X.sup.1 and X.sup.3 represents a halogen atom, X.sup.2 and X.sup.4 represent a hydrogen atom or an alkyl group and R.sup.1 represents an aryl group or an alkyl group having 1-7 carbon atoms. In a further preferred combination of them, both of X.sup.1 and X.sup.3 represent a chlorine atom or bromine atom, X.sup.2 represents a hydrogen atom or an alkyl group, X.sup.4 represent a hydrogen atom and R.sup.1 represents an aryl group.

The compound represented by the formula (2) has a total molecular weight in the range of preferably 170-800, more preferably 220-650, particularly preferably 220-500.

Specific examples of the compound represented by the formula (2) will be listed below. However, compounds of the formula (2) that can be used in the present invention are not limited to these specific examples. ##STR10## ##STR11## ##STR12## ##STR13## ##STR14## ##STR15## ##STR16## ##STR17## ##STR18## ##STR19## ##STR20##

The compound represented by the formula (2) used in the present invention can be readily synthesized by a method for synthesizing a phenol coupler known in the field of photography, for example, a method utilizing a reaction of an o-aminophenol and an acid halide.

The amount of the phenol compound represented by the formula (2) is preferably 0.001-4.0 g, more preferably 0.01-2.0 g, further preferably 0.1-2.0 g, per 1 m.sup.2 of the photothermographic material. Further, the amount of the compound represented by the formula (2) is preferably 0.1-1000 mole %, more preferably 1-100 mole %, particularly preferably 5-50 mole %, with respect to the compound represented by the formula (1). The compounds represented by the formula (2) may be used each alone, or as a combination of two or more of them.

The compound represented by the formula (2) may be used after being dissolved in water or an appropriate organic solvent such as alcohols (e.g., methanol, ethanol, propanol, fluorinated alcohol etc.), ketones (e.g., acetone, methyl ethyl ketone etc.), dimethylformamide, dimethyl sulfoxide or methyl cellosolve. Further, they may also be used as an emulsion dispersion mechanically prepared according to an already well known emulsion dispersion method by using an oil such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate, ethyl acetate or cyclohexanone as an auxiliary solvent for dissolution. Alternatively, the compound of the formula (2) may be used by dispersing its powder in water by using a ball mill, colloid mill, sand grinder mill, MANTON GAULIN, microfluidizer, or by means of ultrasonic wave according to a known method for solid dispersion.

While the compound represented by the formula (2) may be added to any layer on the same side as the aforementioned photosensitive silver halide and reducible silver salt, it is preferably added to a layer containing silver halide or a layer adjacent thereto.

The photothermographic material of the present invention may contain a compound called "color tone adjuster" as required in order to improve image density of silver images, color tone of silver and heat developability.

For photothermographic materials using a silver salt of an organic acid, color tone adjusters of a wide range have been disclosed. For example, there can be mentioned color tone adjusters disclosed in JP-A-46-6077, JP-A-47-10282, JP-A-49-5019, JP-A-49-5020, JP-A-49-91215, JP-A-50-2524, JP-A-50-32927, JP-A-50-67132, JP-A-50-67641, JP-A-50-114217, JP-A-51-3223, JP-A-51-27923, JP-A-52-14788, JP-A-52-99813, JP-A-53-1020, JP-A-53-76020, JP-A-54-156524, JP-A-54-156525, JP-A-61-183642, JP-A-4-56848, Japanese Patent Publication (Kokoku, hereinafter referred to as JP-B) 49-10727, JP-B-54-20333, U.S. Pat. Nos. 3,080,254, 3,446,648, 3,782,941, 4,123,282 and 4,510,236, British Patent No. 1,380,795, Belgian Patent No. 841,910, JP-B-1-25050 and so forth. Specific examples of the color tone adjuster include phthalimide and N-hydroxyphthalimide; succinimide, pyrazolin-5-ones and cyclic imides such as quinazolinone, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and 2,4-thiazolidinedione; naphthalimides such as N-hydroxy-1,8-naphthalimide; cobalt complexes such as cobalt hexaminetrifluoroacetate; mercaptanes such as 3-mercapto-1,2,4-triazole, 2,4-dimercaptopyrimidine, 3-mercapto-4,5-diphenyl-1,2,4-triazole and 2,5-dimercapto-1,3,4-thiadiazole; N-(aminomethyl)aryldicarboxyimides such as N,N-(dimethylaminomethyl)phthalimide and N,N-(dimethylaminomethyl)naphthalene-2,3-dicarboxyimide; blocked pyrazoles, isothiuronium derivatives and a certain kind of photobleaching agents such as N,N'-hexamethylenebis(1-carbamoyl-3,5-dimethylpyrazole), 1,8-(3,6-diazaoctane)bis(isothiuroniumtrifluoroacetate) and 2-(tribromomethylsulfonyl)benzothiazole; 3-ethyl-5-[(3-ethyl-2-benzothiazolinylidene)-1-methylethylidene]-2-thio-2, 4-oxazolidinedione; phthalazinone, phthalazinone one derivatives and metal salts thereof, such as 4-(1-naphthyl)phthalazinone, 6-chlorophthalazinone, 5,7-dimethyloxyphthalazinone and 2,3-dihydro-1,4-phthalazinedione; combinations of phthalazinone with a phthalic acid derivative (e.g., phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid, tetrachlorophthalic acid anhydride, homophthalic acid); phthalazine, phthalazine derivatives (e.g., 4-(1-naphthyl)phthalazine, 6-chlorophthalazine, 5,7-dimethoxyphthalazine, 6-isopropylphthalazine, 6-isobutylphthalazine, 6-tert-butyl-phthalazine, 5,7-dimethylphthalazine, 2,3-dihydrophthalazine) and metal salts thereof; combinations of phthalazine or a derivative thereof and a phthalic acid derivative (e.g., phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid, tetrachlorophthalic acid anhydride, homophthalic acid etc.); quinazolinedione, benzoxazine and naphthoxazine derivatives; rhodium complexes that function not only as a color tone adjuster but also as a halide ion source for the formation of silver halide at the site, such as ammonium hexachlororhodate(III), rhodium bromide, rhodium nitrate and potassium hexachlororhodate (III); inorganic peroxides and persulfates such as ammonium disulfide peroxide and hydrogen peroxide; benzoxazine-2,4-diones such as 1,3-benzoxazine-2,4-dione, 8-methyl-1,3-benzoxazine-2,4-dione and 6-nitro-1,3-benzoxazine-2,4-dione; pyrimidines and asymmetric triazines such as 2,4-dihydroxpyrimidine and 2-hydroxy-4-aminopyrimidine; azauracil and tetraazapentalene derivatives such as 3,6-dimercapto-1,4-diphenyl-1H,4H-2,3a,5,6a-tetraazapentalene and 1,4-di(o-chlorophenyl)-3,6-dimercapto-1H,4H-2,3a,5,6a-tetraazapentalene and so forth.

The color tone adjusters have been searched in view of desired performances (image density, silver color tone, improvement of heat developability), properties for volatilization, sublimation or the like from photosensitive materials, properties of photosensitive materials comprising them in combination with other additives such as antifoggants. It is known that superior results can be obtained by, inter alia, a combinations of a phthalazine compound represented by the formula (3) and a phthalic acid derivative.

The photothermographic material of the present invention preferably further contains a phthalazine compound represented by the formula (3). ##STR21##

In the formula (3), Y represents a hydrogen atom or a monovalent substituent, and m represents an integer of 1 to 6. That is, (Y)m means that 1-6 of Y independently exist on the phthalazine ring, and when m is 2 or more, adjacent two of Y may form an aliphatic or aromatic ring.

Examples of the substituents represented by Y include, for example, an alkyl group having preferably 1-20 carbon atoms, more preferably 1-12 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, iso-butyl group, tert-butyl group, n-octyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group etc.), an alkenyl group preferably having 2-20 carbon atoms, more preferably 2-12 carbon atoms, particularly preferably 2-8 carbon atoms (e.g., vinyl group, allyl group, 2-butenyl group, 3-pentenyl group etc.), an alkynyl group preferably having 2-20 carbon atoms, more preferably 2-12 carbon atoms, particularly preferably 2-8 carbon atoms (e.g., propargyl group, 3-pentynyl group etc.), an aryl group preferably having 6-30 carbon atoms, more preferably 6-20 carbon atoms, particularly preferably 6-12 carbon atoms (e.g., phenyl group, p-methylphenyl group, naphthyl group etc.), an aralkyl group preferably having 7-30 carbon atoms, more preferably 7-20 carbon atoms, still more preferably 7-12 carbon atoms, particularly preferably 7 or 8 carbon atoms (e.g., benzyl group, .alpha.-methylmenzyl group, 2-phenylethyl group, naphthylmethyl group, (4-methylphenyl)methyl group etc.), an amino group preferably having 0-20 carbon atoms, more preferably 0-10 carbon atoms, particularly preferably 0-6 carbon atoms (e.g., amino group, methylamino group, dimethylamino group, diethylamino group, dibenzylamino etc.), an alkoxy group preferably having 1-20 carbon atoms, more preferably 1-12 carbon atoms, particularly preferably 1-8 carbon atoms (e.g., methoxy, ethoxy, butoxy etc.), an aryloxy group preferably having 6-20 carbon atoms, more preferably 6-16 carbon atoms, particularly preferably 6-12 carbon atoms (e.g., phenyloxy group, 2-naphthyloxy group etc.), an acyl group preferably having 1-20 carbon atoms, more preferably 1-16 carbon atoms, particularly preferably 1-12 carbon atoms (e.g., acetyl group, benzoyl group, formyl group, pivaloyl group etc.) an alkoxycarbonyl group preferably having 2-20 carbon atoms, more preferably 2-16 carbon atoms, particularly preferably 2-12 carbon atoms (e.g., methoxycarbonyl group, ethoxycarbonyl group etc.), an aryloxycarbonyl group preferably having 7-20 carbon atoms, more preferably 7-16 carbon atoms, particularly preferably 7-10 carbon atoms (e.g., phenyloxycarbonyl group etc.), an acyloxy group preferably having 2-20 carbon atoms, more preferably 2-16 carbon atoms, particularly preferably 2-10 carbon atoms (e.g., acetoxy group, benzoyloxy group etc.), an acylamino group preferably having 2-20 carbon atoms, more preferably 2-16 carbon atoms, particularly preferably 2-10 carbon atoms (e.g., acetylamino group, benzoylamino group etc.), an alkoxycarbonylamino group preferably having 2-20 carbon atoms, more preferably 2-16 carbon atoms, particularly preferably 2-12 carbon atoms (e.g., methoxycarbonylamino group etc.), an aryloxycarbonylamino group preferably having 7-20 carbon atoms, more preferably 7-16 carbon atoms, particularly preferably 7-12 carbon atoms (e.g., phenyloxycarbonylamino group etc.), a sulfonylamino group preferably having 1-20 carbon atoms, more preferably 1-16 carbon atoms, particularly preferably 1-12 carbon atoms (e.g., methanesulfonylamino group, benzenesulfonylamino group etc.), a sulfamoyl group preferably having 0-20 carbon atoms, more preferably 0-16 carbon atoms, pa