JPH0690487B2 - Photothermographic material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a photothermographic material, and more particularly to a photothermographic material having a layer containing a modified polyvinyl alcohol polymer having excellent compatibility with gelatin and the like. It is a thing.

[Prior Art] The conventionally known photographic method using photosensitive silver halide is superior to other photographic methods in terms of photosensitivity, gradation and image storability, and has been most widely used. It is a photographic method.

However, in this method, since a wet processing method is used for processing steps such as development, fixing, and washing with water, the processing takes time and labor, and there is concern that the processing chemicals may affect the human body, or the processing room or work There are many problems such as concern about contamination of the person by the above chemicals, and consideration of pollution caused by waste liquid. Therefore, it has been desired to develop a photosensitive material which uses photosensitive silver halide and which can be dry-processed.

Although many proposals have been made regarding the above dry processing photographic method, a photothermographic material capable of performing a developing step by heat treatment has been attracting attention as a photosensitive material satisfying the above demand.

For such a photothermographic material, for example, Japanese Patent Publication No. 43-4
Nos. 921 and 43-4924 disclose the same, and a light-sensitive material comprising an organic silver salt, a silver halide and a reducing agent is disclosed.

Attempts have been made to improve the photothermographic material and obtain a color image by various methods.

For example, in U.S. Pat. Nos. 3,531,286, 3,761,270, 3,764,328 and the like, heat-developable color sensitizers for forming a color image by reacting an oxidant of an aromatic primary amine developing agent with a coupler. Materials are disclosed.

Research Disclosure No. 15108 and 1
Japanese Patent No. 5127 discloses a heat-developable color light-sensitive material which forms a color image by reacting an oxidized product of a sulfonamidephenol or sulfonamideaniline derivative developing agent with a coupler. However, in these methods, after heat development, an image of reduced silver and a color image are simultaneously generated in the exposed area, so that there is a problem that the color image becomes turbid. As a method for solving this problem, a silver image is formed. There is a method of removing it by liquid treatment or transferring only the dye to another layer, for example, an image receiving sheet having an image receiving layer.

In addition, in Research Disclosure No. 16966, an organic imino silver salt having a dye part is used, and the imino group is released in the exposed part by heat development, and a solvent is used to form a color image on the image receiving layer as a transfer paper. A color light-sensitive material is disclosed.

Further, JP-A-52-105821, JP-A-52-105822 and JP-A-56-50328
Publications, U.S. Pat.No. 4,235,957, Research
Disclosure 14448, 15227 and 18137
U.S. Pat. No. 4,968,961 discloses a heat-developable color light-sensitive material capable of forming a positive color image by a heat-sensitive silver dye bleaching method.

Further, in U.S. Pat.Nos. 3,180,732, 3,985,565 and 4,022,617 and Research Disclosure 12533, a heat-developable color photosensitive material for forming a color image using a leuco dye is disclosed. .

Furthermore, JP-A-57-179840 discloses a heat-developable color light-sensitive material in which a color image is formed by using a dye-releasing aid and a reducing dye-donor substance that releases a diffusible dye.

Furthermore, JP-A-57-186744, JP-A-58-123533, and JP-A-58-1
Each publication of 49046 discloses a heat-developable color light-sensitive material for obtaining a transferred color image by releasing or forming a diffusible dye by heat development.

Gelatin has conventionally been used as a binder for the photosensitive layer of a heat-developable light-sensitive material, but it has the drawback of poor heat developability because it is not thermoplastic. In particular, when gelatin is used as a binder of the photosensitive layer of a transfer type photothermographic material, the dye permeability is poor. In order to improve this, there is a method in which gelatin is mixed with polyvinyl alcohol, polyvinyl pyrrolidone, or polyvinyl butyral. According to this method, the heat developability and the dye permeability are slightly improved as compared with the case where only gelatin is used, but it is still insufficient, and the compatibility with the above-mentioned polymer mixed with gelatin is poor, so that in the transfer type. Transfer unevenness is likely to occur.

Generally, three layers of full-color light-sensitive materials are layered.
It is common to have an intermediate layer separating the photosensitive layers in addition to the photosensitive layers sensitive to different types of spectral sensitivity regions.
In a normal color light-sensitive material, the same gelatin as that of the emulsion layer is used in consideration of the permeability of an alkaline aqueous solution, the set coatability and the like. However, in the transfer type photothermographic material, a film having good permeability of the released or formed dye is required in order to diffuse the dye in the layered film in a substantially water-free state.

Gelatin is advantageous in that the film is highly uniform because it can be coated in multiple layers at the same time as the photosensitive layer and can be set-coated, but in the case where the release in the dry film or the permeability of the formed dye is gelatin. Since it is low, it has been proposed to use gelatin in combination with other polymers, as described in Japanese Patent Application No. 58-223274.

In particular, an attempt has been made to improve the permeability of the dye while maintaining the above advantages of using gelatin by using gelatin in combination with other water-soluble thermoplastic polymer such as polyvinyl acetal, polyvinyl alcohol, polyvinylpyrrolidone. However, it is desired that uniform coating is difficult and that the dye permeability is further improved.

Further, it is generally known to provide a protective film on a photosensitive material. Also in the photothermographic material, a protective film is coated for the purpose of preventing scratches, improving developability, and preventing smoke emission. When gelatin, for example, is used as the protective film, it is characterized in that it can be applied uniformly, but it hinders the thermal transfer of the released dye and is not very effective for the stickiness of the film. Further, polyvinyl alcohol and the like have little inhibition of the transferability of the dye and have a considerable performance as a protective film, but are inferior to gelatin in coating property. Gelatin has good coating properties because it has the property of being set-coatable.
Generally, gelatin and other aqueous polymer are mixed and applied.

However, even if gelatin and polyvinyl alcohol are mixed and applied, it is difficult to form a very uniform film and satisfactory performance cannot be obtained.

The present situation is that none of the mixed films of other water-soluble polymers and gelatin can sufficiently achieve the above object.

[Object of the Invention] In view of the above-mentioned conventional drawbacks, the present invention provides a modified polyvinyl alcohol-based polymer having excellent compatibility with gelatin or the like as a binder of a photosensitive layer, an intermediate layer provided between photosensitive layers, or a protective film. It is an object of the present invention to provide a photothermographic material containing the photothermographic material, which has good heat developability and dye permeability, has no transfer unevenness, and has excellent coatability during production.

[Constitution of Invention] The above object of the present invention is to provide a photothermographic material having a photosensitive layer containing at least silver halide grains on a support, wherein the photosensitive material is a polyvinyl alcohol polymer (hereinafter referred to as PVA-based polymer). PVA for a polymer having an ionic group, which has a layer containing a water-soluble or water-dispersible block copolymer containing a polymer having an ionic group as another component This is achieved by providing a photothermographic material in which the weight ratio of the system polymer is 0.2 or more and 50 or less.

[Concrete Structure of the Invention] A water-soluble or water-dispersible block copolymer (hereinafter simply referred to as “the PVA polymer used in the present invention as one component and a polymer having an ionic group as another component” The modified PVA-based polymer) can be produced by various arbitrary methods, for example, a mercapto group at the terminal obtained by saponifying a polyvinyl ester-based polymer having a thiol ester group at the terminal. Most preferred is a method of producing a radically polymerizable monomer having an ionic group by radical polymerization in the presence of a PVA-based polymer having

The details of the method will be described below.

First of all, the PVA-based polymer having a mercapto group at the terminal is obtained by polymerizing a vinyl monomer mainly composed of vinyl ester monomers in the presence of thiol acid to saponify the polyvinyl ester-based polymer by a conventional method. can get.

The thiol acid used here includes an organic thiol acid having a -COSH group. Examples thereof include thiol acetic acid, thiol propionic acid, thiol butyric acid, and thiol valeric acid. Thiol acetic acid is particularly preferable because of its degradability.

The amount of thiol acid added to the polymerization system and the method of addition are not particularly limited and are appropriately determined depending on the physical properties of the desired PVA polymer.

Further, the vinyl ester can be used as long as it is a radically polymerizable vinyl ester, for example, vinyl formate, vinyl acetate,
Examples thereof include vinyl propionate, vinyl versatate, vinyl laurate, vinyl stearate and the like, and vinyl acetate is particularly preferred because it has the highest polymerizability.

Polymerization of vinyl monomers mainly composed of vinyl esters such as vinyl acetate in the presence of thiol acid can be carried out by any method such as bulk polymerization method, solution polymerization method, pearl polymerization method and emulsion polymerization method in the presence of a radical polymerization initiator. Although it can be carried out, the solution polymerization method using methanol as a solvent is industrially most advantageous. A known process such as a batch process, a semi-continuous process, or a continuous process can be adopted as the polymerization process.

Examples of the radical polymerization initiator include known radical polymerization initiators such as 2,2′-azobisisobutyronitrile, benzoyl peroxide, and carbonate carbonate, and 2,2′-azobisisobutyronitrile and the like. Azo initiators are particularly preferable because they are easy to handle. Also, the polymerization can be carried out by using radiation, electron beam or the like. The polymerization temperature is preferably selected from the range of 30 to 90 ° C, although it is desirable to adopt an appropriate temperature depending on the kind of the initiator used. After polymerization for a predetermined period of time, unpolymerized vinyl esters are removed by a usual method to obtain a polyvinyl ester polymer having a thiolate ester group at the terminal.

The polyvinyl ester-based polymer thus obtained is saponified by a conventional method, but it is usually advantageous to carry out the polyvinyl ester-based polymer as an alcohol solution, particularly a methanol solution. As the alcohol, not only an anhydride but also a small amount of a water-containing alcohol may be used according to the purpose, and an organic solvent such as methyl acetate or ethyl acetate may be optionally contained. The saponification temperature is usually selected from the range of 10 to 70 ° C. As the saponification catalyst, alkaline catalysts such as sodium hydroxide, potassium hydroxide, sodium methylate and potassium methylate are preferable. The amount of the saponification catalyst used is appropriately determined depending on the degree of saponification, the amount of water, etc., but it is desirable to use 0.001 or more, preferably 0.002 or more in molar ratio to the vinyl ester unit. On the other hand, since the residual alkali is removed from the polymer, the molar ratio is preferably 0.2 or less.

This saponification reaction saponifies the terminal thiolate ester of the polyvinyl ester polymer having a thiolate ester group at the end and the vinyl ester bond of the main chain, the polymer end is a mercapto group, and the main chain becomes vinyl alcohol, The degree of saponification of the vinyl ester unit in the main chain can be changed according to the purpose of use, but is preferably 20 mol% or more, more preferably 50 mol% or more, and further preferably 70 mol% or more, without any particular limitation. The polymer precipitated after the saponification reaction is purified by a known method such as washing with methanol, residual alkali, and impurities such as an alkali metal salt of acetic acid are removed and dried to usually obtain a mercapto group at the end as a white powder. A PVA-based polymer having is obtained.

Next, a method of radically polymerizing a monomer having an ionic group in the presence of a PVA-based polymer having a mercapto group at the terminal will be described. As the polymerization method, a generally known method, for example, any method such as bulk polymerization, solution polymerization, pearl polymerization, and emulsion polymerization can be adopted, but a solvent capable of dissolving the PVA-based polymer, such as water or dimethyl sulfoxide, can be used. It is particularly preferred to carry out the polymerization in a predominant medium. As the polymerization process, the batch method,
Both the semi-batch method and the continuous method can be adopted.

Examples of the radical polymerization initiator for the radical polymerization include, for example, 2,2′-azobisisobutyronitrile, benzoyl peroxide, lauroyl peroxide, diisopropyl peroxycarbonate, potassium persulfate, ammonium persulfate, etc. In the case of water-based polymerization, redox initiation is also possible with a mercapto group at the PVA end and an oxidizing agent such as potassium bromate, potassium persulfate, ammonium persulfate, or hydrogen peroxide. Among them, potassium bromate does not generate a radical by itself under ordinary polymerization conditions, and decomposes only by a redox reaction with a mercapto group at the PVA terminal to generate a radical, thereby synthesizing the above block copolymer. Above all, it is a particularly preferable initiator.

When radical polymerization is carried out in the presence of the above-mentioned PVA-based polymer having a mercapto group, the polymerization system is preferably acidic. This is because when the mercapto group is basic, the rate of ionic addition to and disappearance from the double bond of the monomer is large, and the polymerization efficiency is significantly reduced. It is desirable to carry out at pH 4 or less.

The PVA-based polymer as referred to in the present invention is preferably a polymer containing 20 mol% or more of vinyl alcohol units, more preferably 50 mol% or more, and further preferably 70 mol% or more, As other monomer components, for example, vinyl acetate, vinyl formate, vinyl propionate, vinyl versatate, ethylene, propylene, (meth) acrylic acid and salts thereof, itaconic acid, maleic acid,
It may contain fumaric acid and salts thereof, 2-acrylamidopropanesulfonic acid and salts thereof, (meth) acrylamidopropyltrimethylammonium chloride and the like. The degree of polymerization is preferably 10 or more and 3500 or less, but is not particularly limited.

In the modified PVA-based polymer, other components than the PVA-based polymer component are not particularly limited as long as they are polymers containing an ionic group, and for example, radical (co) polymerizable ionic monomers such as acryl Acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, vinyl sulfuric acid, vinyl sulfonic acid, p-styrene sulfonic acid, 2-acrylamido propane sulfonic acid, 2-acryloyloxyethyl phosphoric acid, etc., and their metal salts and ammonium salts. Anionic monomer, a homopolymer or copolymer of a cationic monomer such as dimethylaminoethyl (meth) acrylate or (meth) acrylamidopropyltrimethylammonium chloride, or the above ionic monomer and acrylamide, methacrylamide, N, N -Dimethylacrylamide, N-bi Rupiroridon, (meth) acrylate, (meth) acrylate, (meth) acrylonitrile, ethylene, composed of a copolymer of radically (co) polymerizable nonionic monomers such as propylene.

Of the above radical (co) polymerizable ionic monomers,
In particular, monomers containing a carboxyl group (including metal salt and ammonium salt) such as acrylic acid and methacrylic acid, or sulfonic acid groups (metal salt and metal carboxylic acid) such as vinyl sulfonic acid, p-styrene sulfonic acid, and 2-acrylamido propane sulfonic acid. (Including ammonium salts), etc., and among the nonionic monomers that can be copolymerized with these ionic monomers, especially acrylamide,
Methacrylamide, N, N-dimethylacrylamide, N
-Vinylpyrrolidone and the like are preferable as the monomer constituting the ionic polymer. The amount of ionic groups in the ionic polymer is 0.5 mol% because it interacts with gelatin.
The amount is preferably 1 mol% or more, more preferably 2 mol% or more.

The weight ratio of the PVA polymer component in the modified PVA polymer and the ionic polymer which is another component is not particularly limited, but preferably 0.2 ≦ (PVA polymer) / (ionic weight). Combined) ≦ 50, more preferably 0.3 ≦ (PVA-based polymer) / (ionic polymer) ≦ 40, and at this time, the compatibility with gelatin and the like is particularly excellent.

The binder used in the photosensitive layer of the photothermographic material of the present invention includes the modified PVA polymer or the modified PVA.
Polymers and polyvinyl butyral, polyvinyl acetate, ethyl cellulose, polymethylmethacrylate, cellulose acetate butyrate, polyvinyl alcohol, polyvinylpyrrolidone, gelatin and phthalated gelatin are used in combination with one or more polymer substances. I can do this. Particularly, it is preferable to use gelatin or a derivative thereof and a modified PVA polymer in combination.

In the case of using the above polymeric substance and a modified PVA polymer in combination,
This weight ratio is as follows: Polymer: Modified PVA polymer = 1: 9-9:
1 is preferable, and more preferably 2: 8 to 7: 3.

The gelatin may be lime-treated or acid-treated, and may be ossein gelatin, pigskin gelatin, hide gelatin or modified gelatin obtained by esterification or phenylcarbamoylation thereof.

The amount of binder used is usually 0 per 1 m ² per layer.
05g to 50g, preferably 0.1g to 10g. Also,
The binder is 0 for 1 g of the dye-donor monomer unit.
It is preferable to use 1 to 10 g, more preferably 0.25 to 4 g
Is.

As the intermediate layer which is optionally used in the photothermographic material of the present invention, the modified PVA polymer may be used alone, but is preferably used in combination with gelatin, a gelatin derivative or a water-soluble polymer substance. It

The gelatin used in combination may be lime-treated or acid-treated, and may be ossein gelatin, pigskin gelatin, hide gelatin, or modified gelatin obtained by esterification or phenylcarbamoylation thereof.

As the water-soluble polymer substance used in combination, polyvinyl butyral, polyvinyl acetate, ethyl cellulose, polymethyl methacrylate, cellulose acetate butyrate,
Examples thereof include polyvinyl alcohol and polyvinylpyrrolidone, and these can be used alone or in combination of two or more.

When the gelatin or the like and a modified PVA-based polymer are used in combination as the intermediate layer, the modified PVA-based polymer is preferably contained in an amount of 10 to 90% by weight, more preferably 40 to 90% by weight.

The coating amount of the intermediate layer is usually 0.01 g to 1 per 1 m ² per layer.
It is 0 g, preferably 0.05 g to 5 g.

As the protective film optionally used in the photothermographic material of the present invention, the modified PVA polymer may be used alone, but is preferably used in combination with gelatin, a gelatin derivative or another water-soluble polymer substance. To be done.

The gelatin used in combination may be lime-treated or acid-treated, and may be ossein gelatin, pigskin gelatin, hide gelatin, or modified gelatin obtained by esterification or phenylcarbamoylation thereof.

As the water-soluble polymer substance used in combination, polyvinyl butyral, polyvinyl acetate, ethyl cellulose, polymethyl methacrylate, cellulose acetate butyrate,
Examples thereof include polyvinyl alcohol and polyvinylpyrrolidone, and these can be used alone or in combination of two or more.

When the gelatin or the like and a modified PVA-based polymer are used together as a protective film, the modified PVA-based polymer is preferably contained in an amount of 10 to 90% by weight, more preferably 30 to 80% by weight.

The coating amount of the protective film is usually 0.1 to ² per 1 m ² per layer.
It is 0 g, preferably 1 g to 5 g.

A component other than silver halide, such as a thermal solvent, an organic silver salt, a reducing agent, etc., may be added to the protective film. When the photothermographic material is a transfer type, the adhesion to the image receiving layer and the property after transfer are A matting agent may be used in combination for improving the peelability, or a heat-melting compound such as wax may be mixed.

The dye-providing substance that can be used in the present invention will be described. The dye-donating substance may be any one as long as it can participate in the reduction reaction of the photosensitive silver halide and / or the organic silver salt optionally used and can form or release a diffusible dye as a function of the reaction, Depending on the reaction mode,
Negative-type dye-donors that act on positive functions (ie,
A negative dye image is formed when a negative silver halide is used) and a positive dye-donor which acts on a negative function (that is, a positive dye image when a negative silver halide is used) Form)). Negative type dye-donor substances are further classified as follows.

That is, the negative dye-providing substance is divided into a compound that releases a diffusible dye when oxidized (a reducing dye-releasing compound) and a compound that forms a diffusible dye by a coupling reaction with a reducing agent, and the latter. Can be further divided into coupling dye releasing compounds and coupling dye forming compounds.

Each dye-donor will be further described.

Examples of the reducing dye releasing compound include compounds represented by the general formula (1).

Formula (1) Car-NHSO ₂ -Dye wherein Car, upon reduction of the organic silver salt used in accordance with the photosensitive silver halide and / or necessary, reducing the substrate (so-called carrier that releases the oxidized dye ), And Dye is a diffusible dye residue.

Specific examples of the above reducing dye-releasing compound include those disclosed in JP-A-
57-179840, 58-116537, 59-60434, 59
-65839, 59-71046, 59-87450, 59-887
No. 30, 59-123837, 59-165054, 59-165055
The following compounds are mentioned, for example.

As another reducing dye-releasing compound, for example, general formula (2)
The compound shown by is mentioned.

General formula (2) In the formula, A ₁ and A ₂ each represent a hydrogen atom, a hydroxy group or an amino group, and Dye has the same meaning as Dye represented by the general formula (1). Specific examples of the above compounds are shown in JP-A-59-124329.

As the coupling dye-releasing compound, a compound represented by the general formula (3)
The compound shown by is mentioned.

General formula (3) Cp ₁ J _n Dye In the formula, Cp ₁ is an organic group capable of reacting with an oxidant of a reducing agent to release a diffusible dye (so-called coupler residue).
And J is a divalent linking group, and the bond between Cp ₁ and J is cleaved by the reaction with the oxidized form of the reducing agent. n is 0 or 1
And Dye has the same meaning as defined in the general formula (1). Further, Cp ₁ is preferably substituted with various ballast groups in order to make the coupling dye-releasing compound non-diffusible. The ballast group has 8 or more carbon atoms depending on the form of the photosensitive material used. (More preferably 12
Or more) organic groups, or hydrophilic groups such as sulfo groups and carboxy groups, or groups having both 8 or more (more preferably 12 or more) carbon atoms and hydrophilic groups such as sulfo groups and carboxy groups. is there. Another particularly preferred ballast group may include a polymer chain.

Specific examples of the compound represented by the above general formula (3) include JP-A Nos. 57-186744, 57-122596, and 57-1606.
98, 59-174834, 57-224883, 59-159159
And Japanese Patent Application No. 59-104901, and examples thereof include the following compounds.

Examples of the coupling dye forming compound include compounds represented by the general formula (4).

General formula (4) Cp ₂ XQ) has the same meaning, Y represents an alkylene group, an arylene group or an aralkylene group, Z represents a divalent organic group, and L represents an ethylenically unsaturated group or an ethylenically unsaturated group. Represents a group having.

Specific examples of the coupling dye-forming compounds represented by the general formulas (4) and (5) are described in JP-A-59-124339 and JP-A-59-124339.
59-181345, Japanese Patent Application No. 58-109293, 59-179657,
No. 59-181604, No. 59-182506, No. 59-182507, and the like, and the following compounds are exemplified.

In the formula, Cp ₂ is an organic group (so-called coupler residue) capable of reacting with an oxidized form of a reducing agent (coupling reaction) to form a diffusible dye, and X represents a divalent linking group. , Q represents a ballast group.

The coupler residue represented by Cp ₂ has a molecular weight of preferably 700 or less, more preferably 500 or less because of the diffusibility of the dye formed.

Further, the ballast group is preferably the same ballast group as the ballast group defined by the general formula (3), particularly 8 or more (more preferably 12 or more) carbon atoms and a hydrophilic group such as a sulfo group or a carboxy group. A group having both groups is preferable, and a polymer chain is more preferable.

As the coupling dye forming compound having this polymer chain, a polymer having a repeating unit derived from the monomer represented by the general formula (5) is preferable.

General formula (5) Cp ₂ XY _l ZL) In the formula, Cp ₂ and X are as defined in the general formula (4). polymer In the above general formulas (3), (4) and (5), Cp ₁
Further, the coupler residue defined by Cp ₂ will be described in more detail, and a group represented by the following general formula is preferred.

In the formula, R ₁ , R ₂ , R ₃ and R ₄ are each a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an aryl group, an acyl group, an alkyloxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, aryl. Sulfonyl group, carbamoyl group, sulfamoyl group, acyloxy group, amino group, alkoxy group, aryloxy group,
Represents a cyano group, a ureido group, an alkylthio group, an arylthio group, a carboxy group, a sulfo group or a heterocyclic residue,
These are further substituted with hydroxyl group, carboxy group, sulfo group, alkoxy group, cyano group, nitro group, alkyl group, aryl group, aryloxy group, acyloxy group, acyl group, sulfamoyl group, carbamoyl group, imide group, halogen atom, etc. It may have been done.

These substituents are selected according to the purpose of Cp ₁ and Cp ₂ ,
As described above, in Cp ₁ , _one of the substituents is preferably a ballast group, and in Cp ₂ , it is substituted so that the molecular weight is 700 or less, more preferably 500 or less in order to enhance the diffusibility of the dye formed. It is preferred that a group is selected.

As the positive type dye-donating substance, for example, the following general formula (1
There are oxidizing dye-releasing compounds represented by 6).

General formula (16) In the formula, W ₁ represents a group of atoms necessary for forming a quinone ring (which may have a substituent on this ring), and R ₅
Represents an alkyl group or a hydrogen atom, and E represents (In the formula, R ₆ represents an alkyl group or a hydrogen atom, and R ₇ represents an oxygen atom or Represents ) Or —SO ₂ —, r represents 0 or 1, and Dye has the same meaning as defined in formula (1). Specific examples of this compound are disclosed in JP-A-59-166954 and JP-A-59-166954.
No. 154445 and the like, and examples thereof include the following compounds.

Another positive dye-donating substance is a compound represented by the following general formula (17), which loses its dye releasing ability when oxidized.

General formula (17) In the formula, W ₂ represents a group of atoms necessary for forming a benzene ring (which may have a substituent on the ring), R ₅ ,
E and Dye have the same meaning as defined by the general formula (16). Specific examples of this compound are disclosed in JP-A-59-124329 and 59-124.
No. 154445 and the like, and examples thereof include the following compounds.

Still another positive type dye-providing substance is a compound represented by the following general formula (18).

General formula (18) In the above formula, W ₂ , R ₅ and Dye have the same meanings as defined in the general formula (17). Specific examples of this compound are described in JP-A-59-154445 and the like, for example, the following compounds.

The above general formulas (1), (2), (3), (16), (17)
Further, the residue of the diffusible dye represented by Dye in (18) will be described in more detail. As the residue of the diffusible dye,
Due to the diffusibility of the dye, the molecular weight is 800 or less, more preferably 6
It is preferably 00 or less, and examples thereof include residues of azo dyes, azomethine dyes, anthraquinone dyes, naphthoquinone dyes, styryl dyes, nitro dyes, quinoline dyes, carbonyl dyes, phthalocyanine dyes and the like. These dye residues may be in the form of a temporary short-wave that allows multiple colors during heat development or transfer. Further, these dye residues are used for the purpose of improving the light resistance of an image, for example, JP-A-59-48765 and 59-1.
The chelatable dye residue described in JP 24337 is also a preferred form.

These dye-providing substances may be used alone or in combination of two or more. The amount thereof is not limited, and may be one kind of dye-donating substance, one kind or a combination of two or more kinds, or a single photosensitive layer of the photothermographic material of the present invention.
It may be determined according to the number of layers or more, but the amount used is, for example, 0.005 g to 50 g, preferably 0.1 g to 1 g per m ^2.
0g can be used.

The method of incorporating the dye-donor substance into the photosensitive layer of the photothermographic material is arbitrary, and examples include low-boiling point solvents (methanol, ethanol, ethyl acetate, etc.) or high-boiling point solvents (dibutyl phthalate, dioctyl phthalate, tricresyl phosphate, etc.). Or ultrasonically dispersed or dissolved in an alkaline aqueous solution (for example, 10% sodium hydroxide aqueous solution) and then neutralized with a mineral acid (for example, hydrochloric acid or nitric acid), or It can be used after being dispersed with a suitable polymer aqueous solution (eg, gelatin, polyvinyl butyral, polyvinyl pyrrolidone, etc.) using a ball mill.

The heat-developable light-sensitive material of the present invention contains a light-sensitive silver halide together with the above-mentioned dye-providing substance.

The photosensitive silver halide used in the present invention includes silver chloride, silver bromide, silver iodide, silver chlorobromide, silver chloroiodide, silver iodobromide,
Examples thereof include silver chloroiodobromide. The photosensitive silver halide is
Although it can be prepared by any method such as a single jet method and a double jet method in the field of photographic technology, in the present invention, a photosensitive silver halide prepared according to a usual method for preparing a silver halide gelatin emulsion is used. A light-sensitive silver halide emulsion containing the same gives favorable results.

The photosensitive silver halide emulsion may be chemically sensitized by any method in the photographic art. As such a sensitizing method,
Various methods such as gold sensitization, sulfur sensitization, gold-sulfur sensitization and reduction sensitization can be used.

The silver halide in the above light-sensitive emulsion may be coarse particles or fine particles, but the preferable grain size is about 0.001 μm to about 1.5 μm, and more preferably about 0.01 μm to about 0.01 μm. It is about 0.5 μm.

The light-sensitive silver halide emulsion prepared as described above can be most preferably applied to the heat-developable light-sensitive layer which is a constituent layer of the heat-developable light-sensitive material of the present invention.

In the present invention, as another method for preparing photosensitive silver halide, a photosensitive silver salt-forming component may be allowed to coexist with an organic silver salt described below to form photosensitive silver halide on a part of the organic silver salt. . As the photosensitive silver salt forming component used in this preparation method, an inorganic halide, for example, a halide represented by MXn (wherein M represents an H atom, an NH ₄ group or a metal atom, and X represents Cl, Br Or I, n
Indicates 1 when M is an H atom or an NH ₄ group, and its valence when M is a metal atom. As the metal atom, lithium, sodium, potassium, rubidium, cesium, copper, gold, beryllium, magnesium, calcium, strontium, barium, zinc, cadmium, mercury, aluminum, indium, lanthanum, ruthenium, thallium, germanium, tin, Lead, antimony, bismuth, chrome,
Molybdenum, tungsten, manganese, rhenium, iron,
Examples thereof include cobalt, nickel, rhodium, palladium, osmium, iridium, platinum and cerium. ),
Halogen-containing metal complex (eg, K ₂ PtCl ₆ , K ₂ PtBr ₆ , HA
_{uCl 4, (NH 4) 2} IrCl 6, (NH 4) 3 IrCl 6, (NH 4) 2 RuCl 6, (NH 4)
₃ RuCl ₆ , (NH ₄ ) ₃ RhCl ₆ , (NH ₄ ) ₃ RuBr _6, etc.), onium halides (eg, tetramethylammonium bromide,
Quaternary ammonium halides such as trimethylphenylammonium bromide, cetylethyldimethylammonium bromide, 3-methylthiazolium bromide, trimethylbenzylammonium bromide, quaternary phosphonium halides such as tetraethylphosphonium bromide, benzylethylmethylsulfonium Bromide, tertiary sulfonium halides such as 1-ethylthiazolium bromide), halogenated hydrocarbons (eg, iodoform, bromoform, carbon tetrabromide, 2-bromo-2-methylpropane, etc.), N-halogen compounds (N-chlorosuccinimide, N-bromosuccinimide, N-bromophthalimide, N-bromoacetamide, N-iodosuccinimide, N-bromophthalazinone, N-ku Rofutarajinon, N- bromo acetanilide, N, N- dibromo benzenesulfonamide,
N-bromo-N-methylbenzenesulfonamide, 1,3
-Dibromo-4,4-dimethylhydantoin, etc.), other halogen-containing compounds (for example, triphenylmethyl chloride,
Triphenylmethyl bromide, 2-bromobutyric acid, 2-bromoethanol, etc.) and the like.

These photosensitive silver halide and photosensitive silver salt-forming component can be used in combination in various methods, and the amount used is
It is preferably 0.001 g to 50 g, and more preferably 0.1 g to 10 g per 1 m ² per layer.

The photothermographic material of the present invention has a multi-layered structure as each layer having photosensitivity to blue light, green light and red light, that is, a photothermographic blue photosensitive layer, a photothermographic green photosensitive layer and a photothermographic red photosensitive layer. You can also Further, the photosensitive layer of the same color may be divided into two or more layers (for example, a high sensitivity layer and a low sensitivity layer).

In the above case, the blue-sensitive silver halide emulsion, green-sensitive silver halide emulsion and red-sensitive silver halide emulsion used in each case are obtained by adding various spectral sensitizing dyes to the silver halide emulsion. You can

Representative spectral sensitizing dyes used in the present invention include, for example, cyanine, merocyanine, complex (trinuclear or tetranuclear) cyanine, holobora cyanine, styryl, hemicyanine, oxonol and the like. Among the cyanine dyes, those having a basic nucleus such as thiazoline, oxazoline, pyrroline, pyridine, oxazole, thiazole, selenazole, and imidazole are more preferable. Such a nucleus may have an alkyl group, an alkylene group, a hydroxyalkyl group, a sulfoalkyl group, a carboxyalkyl group, an aminoalkyl group or an enamine group capable of forming a condensed carbocyclic or heterocyclic ring. Good. Further, it may be symmetrical or asymmetrical, and the methine chain or polymethine chain may have an alkyl group, a phenyl group, an enamine group or a heterocyclic substituent.

The merocyanine dye may have, in addition to the basic nucleus, an acidic nucleus such as a thiohydantoin nucleus, a rhodanine nucleus, an oxazotool acid nucleus, a thiazoline thione nucleus, a malononitrile nucleus, and a pyrazolone nucleus. These acidic nuclei are further alkyl group, alkylene group, phenyl group, carboxyalkyl group, sulfoalkyl group, hydroxyalkyl group,
It may be substituted with an alkoxyalkyl group, an alkylamine group or a heterocyclic nucleus. If necessary, these dyes may be used in combination. Furthermore, ascorbic acid derivatives, azaindene cadmium salts, organic sulfonic acids, etc.
For example, a supersensitizing additive which does not absorb visible light as described in the specifications of US Pat. Nos. 2,933,390 and 2,937,089 can be used in combination.

The addition amount of these dyes is 1 × 10 ⁻⁴ to 1 mol per mol of silver halide or a silver halide-forming component. More preferably, it is 1 × 10 ^-4 mol to 1 × 10 ^-1 mol.

In the photothermographic material of the present invention, various organic silver salts can be used, if necessary, for the purpose of increasing sensitivity and improving developability.

Examples of the organic silver salt used in the photothermographic material of the present invention include JP-B-43-4921, JP-B-44-26582, and JP-B-45-18416.
45-12700, 45-22185, JP-A-49-52626, 52
-31728, 52-137321, 52-141222, 53-36224
No. 53-37610 and other publications and U.S. Pat.
330,633, 3,794,496, 4,105,451, and
4,123,274, silver salts of aliphatic carboxylic acids as described in each specification such as 4,168,980, etc., for example, silver laurate, silver myristate, silver palmitate, silver stearate, silver arachidonate, behen. Acid silver, α- (1-phenyltetrazolethio) acetic acid silver, etc., aromatic carboxylic acid silver salts such as silver benzoate, silver phthalate, etc.
No. 82, No. 45-12700, No. 45-18416, No. 45-22185, JP-A-52-31728, JP-A-52-137321, JP-A-58-118638,
No. 58-118639 and the like, silver salts of imino groups such as silver benzotriazole, silver 5-nitrobenzotriazole, silver 5-chlorobenzotriazole, silver 5-methoxybenzotriazole, and 4- Sulfobenzotriazole silver, 4-hydroxybenzotriazole silver, 5-aminobenzotriazole silver, 5-carboxybenzotriazole silver, imidazole silver, benzimidazole silver, 6-nitrobenzimidazole silver, pyrazole silver, urazole silver, 1,2, 4-triazole silver, 1H-
Tetrazole silver, 3-amino-5-benzylthio-1,2,
4-triazole silver, saccharin silver, phthalazinone silver,
Others such as silver phthalimide, 2-mercaptobenzoxazole silver, mercaptooxadiazole silver, 2-mercaptobenzothiazole silver, 2-mercaptobenzimidazole silver, 3-mercapto-4-phenyl-1,2,4-
Triazole silver, 4-hydroxy-6-methyl-1,3,3
Examples thereof include a, 7-tetrazaindene silver and 5-methyl-7-hydroxy-1,2,3,4,6-pentazaindene silver. Among the above organic silver salts, the silver salt of imino group is preferable, the silver salt of benzotriazole derivative is more preferable, and the silver salt of sulfobenzotriazole derivative is more preferable.

The organic silver salt used in the present invention may be used alone or in combination of two or more kinds, and the isolated silver salt may be dispersed in a binder by a suitable means before use. The silver salt may be prepared in a binder and used as it is without isolation.

The amount of the organic silver salt used is 1 mol of photosensitive silver halide.
It is preferably 0.01 to 500 mol, more preferably
It is 0.1 mol to 100 mol.

The reducing agent used in the photothermographic material of the present invention, it is possible to use those usually used in the field of photothermographic material, for example, U.S. Patent No. 3,531,286, the same 3,761,270,
Nos. 3,764,328, Research Disclosure Nos. 12146, No. 15108, No. 15127, and p-phenylenediamine-based and p-aminophenol-based developments described in JP-A-56-27132. Examples include main agents, phosphoramidophenol-based and sulfonamidephenol-based developing agents, and hydrazone-based color developing agents. Also, U.S. Pat.Nos. 3,342,599 and 3,719,492,
The color developing agent precursors described in JP-A-53-135628 and JP-A-54-79035 can also be advantageously used.

Particularly preferred reducing agents include reducing agents represented by the following general formula (19) described in JP-A-56-146133.

General formula (19) In the formula, R ₈ and R ₉ represent a hydrogen atom or an alkyl group having 1 to 30 (preferably 1 to 4) carbon atoms which may have a substituent, and R ₈ and R ₉ are ring-closed. A heterocycle may be formed. R ₁₀ , R ₁₁ R ₁₂ and R ₁₃ are a hydrogen atom, a halogen atom,
R ₁₀ represents a hydroxy group, an amino group, an alkoxy group, an acylamide group, a sulfonamide group, an alkylsulfonamide group or an optionally substituted alkyl group having 1 to 30 carbon atoms (preferably 1 to 4), and R ₁₀ And R ₈ and R ₁₂ and R ₉
May each be ring-closed to form a heterocycle. M represents a compound containing an alkali metal atom, an ammonium group, a nitrogen-containing organic base or a quaternary nitrogen atom.

The nitrogen-containing organic base in the above general formula (19) is an organic compound containing a nitrogen atom showing basicity capable of forming a salt with an inorganic acid, and particularly important organic bases include amine compounds. Primary amines, secondary amines, tertiary amines, and the like are used as chain amine compounds, and pyridine, quinoline, and piperidine, which are prominent examples of typical heterocyclic organic bases, are used as cyclic amine compounds. , Imidazole and the like. In addition, compounds such as hydroxylamine, hydrazine and amidine are also useful as chain amines. As the salt of the nitrogen-containing organic base, the inorganic acid salt of the above-mentioned organic base (for example, hydrochloride, sulfate, nitrate, etc.) is preferably used.

On the other hand, examples of the compound containing a quaternary nitrogen in the general formula (19) include salts or hydroxides of nitrogen compounds having a tetravalent covalent bond.

The reducing agent represented by the general formula (19) can be produced by a known method,
For example, Houben-Weyl, Mesoden
Der Organischen Kemi (Methoden der Organis
Chen Chemie), Band XI / 2, pages 645 to 703.

Other reducing agents such as those described below can also be used.

For example, phenols (for example, p-phenylphenol, p-methoxyphenol, 2,6-di-tert-butyl-p-cresol, N-methyl-p-aminophenol, etc.), sulfonamide phenols [for example, 4-benzene Sulfonamidophenol, 2-benzenesulfonamidophenol, 2,6-dichloro-4-benzenesulfonamidophenol, 2,6-dibromo-4- (p-toluenesulfonamido) phenol, etc.], or polyhydroxybenzenes (eg, Hydroquinone, tert-butylhydroquinone, 2,6-dimethylhydroquinone, chlorohydroquinone, carboxyhydroquinone, catechol, 3-carboxycatechol, etc., naphthols (for example, α-naphthol, β-naphthol, 4-aminonaphthol, 4-methoxynaphtho). Le etc.), hydroxy binaphthyls and methylene bis naphthols [e.g.
1,1'-dihydroxy-2,2'-binaphthyl, 6,6'-dibromo-2,2'-dihydroxy-1,1'-binaphthyl, 6,
6-dinitro-2,2'-dihydroxy-1,1'-binaphthyl, 4,4'-dimethoxy-1,1'-dihydroxy-2,2 '
-Binaphthyl, bis (2-hydroxy-1-naphthyl)
Methane, etc.], methylenebisphenols [eg 1,1-
Bis (2-hydroxy-3,5-dimethylphenyl) -3,
5,5-trimethylhexane, 1,1-bis (2-hydroxy-3-tert-butyl-5-methylphenyl) methane, 1,
1-bis (2-hydroxy-3,5-di-tert-butylphenyl) methane, 2,6-methylenebis (2-hydroxy-
3-tert-butyl-5-methylphenyl) -4-methylphenol, α-phenyl-α, α-bis (2-hydroxy-3,5-di-tert-butylphenyl) methane, α-
Phenyl-α, α-bis (2-hydroxy-3-tert-
Butyl-5-methylphenyl) methane, 1,1-bis (2
-Hydroxy-3,5-dimethylphenyl) -2-methylpropane, 1,1,5,5-tetrakis (2-hydroxy-3,5
-Dimethylphenyl) -2,4-ethylpentane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3-methyl-5-ter
t-butylphenyl) propane, 2,2-bis (4-hydroxy-3,5-di-tert-butylphenyl) propane, etc.], ascorbic acids, 3-pyrazolidones, pyrazolones, hydrazones and paraphenylenediamines Is mentioned.

These reducing agents may be used alone or in combination of two or more. The amount of the reducing agent used depends on the type of the photosensitive silver halide used, the type of the organic acid silver salt and the type of other additives, but is usually 0.01 per 1 mol of the photosensitive silver halide. The range is ˜1500 mol, preferably 0.1-200 mol.

The support used in the photothermographic material of the present invention includes
For example, a polyethylene film, a cellulose acetate film and a polyethylene terephthalate film, a synthetic plastic film such as polyvinyl chloride, and a paper support such as photographic base paper, printing paper, baryta paper and resin coated paper, and a reflective layer on the above synthetic plastic film. And a support provided with.

Various additives may be added to the photothermographic material of the present invention, if necessary, in addition to the above components. For example, as a development accelerator, U.S. Patent Nos. 3,220,840 and 3,531,285
No. 4,012,260, No. 4,060,420, No. 4,088,49
No. 6, No. 4,207,392 specifications, Research Disclosure No. 15733, No. 15734, No. 15776, JP-A-56
Urea described in No. 130745 and No. 56-132332, alkali releasing agents such as guanidinium trichloroacetate, organic acids described in JP-B-45-12700, -CO- described in U.S. Pat. No. 3,667,959. SO ₂ -, - SO- non-aqueous polar solvent a compound having a group, U.S. Patent No. 3,438,776 No. described melt formers, U.S. Patent No. 3,666,477, polyalkylene glycols and the like is described in JP-a-51-19525 . Examples of color toning agents include JP-A-46-4928, JP-A-46-6077, and JP-A-46-6077.
-5019, 49-5020, 49-91215, 49-107727
No. 50, No. 50-2524, No. 50-67132, No. 50-67641, No. 50-
114217, 52-33722, 52-99813, 53-1020
No. 53, No. 53-55115, No. 53-76020, No. 53-125014, No. 5
4-156523, 54-156524, 54-156525, 54-156
No. 526, No. 55-4060, No. 55-4061, No. 55-32015, etc. and West German Patent No. 2,140,406, No. 2,147,063
No. 2,220,618, U.S. Pat.Nos. 3,080,254, 3,84
No. 7,612, No. 3,782,941, No. 3,994,732, No. 4,1
23,282, 4,201,582 and the like, which are compounds described in each specification, such as phthalazinone, phthalimide, pyrazolone, quinazolinone, N-hydroxynaphthalimide,
Benzoxazine, naphthoxazinedione, 2,3-dihydro-phthalazinedione, 2,3-dihydro-1,3-oxazine-2,4-dione, oxypyridine, aminopyridine, hydroxyquinoline, aminoquinoline, isocarbostyryl , Sulfonamide, 2H-1,3-benzothiazine-2,4- (3H) dione, benzotriazine, mercaptotriazole, dimercaptotetrazapentalene, phthalic acid, naphthalic acid, phthalamic acid, etc., one of these Alternatively, a mixture of more than one and an imidazole compound, a mixture of at least one of an acid or an acid anhydride such as phthalic acid and naphthalic acid, and a phthalazine compound, and further a mixture of phthalazine and maleic acid, itaconic acid, quinolinic acid, gentisic acid. And the like.
Further, 3-amino-5-mercapto-1,2,4-triazoles, 3-acylamino-5-mercapto-1,2, described in JP-A Nos. 58-189628 and 58-193460 are disclosed. 4-
Triazoles are also effective.

Further, as the antifoggant, for example, Japanese Patent Publication No.
-11113, JP-A-49-90118, 49-10724, 49-976
No. 13, No. 50-101019, No. 49-130720, No. 50-123331
No. 51, No. 51-47419, No. 51-57435, No. 51-78227, No. 51
-104338, 53-19825, 53-20923, 51-50725
No. 51, No. 51-3223, No. 51-42529, No. 51-81124, No. 54-
Publications such as 51821 and 55-93149, as well as British Patent No.
1,455,271, U.S. Pat.Nos. 3,885,968, 3,700,457
No. 4,137,079, No. 4,138,265, West German Patent No. 2,
No. 617, 907, a mercuric salt which is a compound described in each specification, or an oxidizing agent (for example, N-halogenoacetamide, N-halogenosuccinimide, perchloric acid and salts thereof, inorganic peroxides, Persulfate, etc.), or acid and salts thereof (eg, sulfinic acid, lithium laurate, rosin, diterpenes, thiosulfonic acid, etc.), or sulfur-containing compounds (eg, mercapto compound-releasing compound, thiouracil, disulfide, sulfur) Single,
Mercapto-1,2,4-triazole, thiazoline thione, polysulfide compound and the like), and other compounds such as oxazoline, 1,2,4-triazole and phthalimide. As another antifoggant, JP-A-59-1
The thiol (preferably thiophenol compound) compounds described in 11636 are also effective.

Other antifoggants include hydroquinone derivatives described in Japanese Patent Application No. 59-56506 (for example, di-t-octylhydroquinone, dodecanylhydroquinone, etc.) and hydroquinone derivatives described in Japanese Patent Application No. 59-66380. A combination with a benzotriazole derivative (for example, 4-sulfobenzotriazole, 5-carboxybenzotriazole, etc.) can be preferably used.

In addition, a printout preventing agent after treatment may be used as a stabilizer at the same time, and examples thereof include JP-A-48-45228 and JP-A-50-1.
No. 19624, No. 50-120328, No. 53-46020 and the like halogenated hydrocarbons, specifically tetrabromobutane, tribromoethanol, 2-bromo-2-tolylacetamide, 2-bromo- 2-tolylsulfonylacetamide, 2-tribromomethylsulfonylbenzothiazole, 2,4-bis (tribromomethyl) -6-methyltriazine and the like can be mentioned.

In particular, it is preferable to add various thermal solvents to the photothermographic material of the present invention. The hot solvent may be a substance that promotes heat development and / or heat transfer, and is preferably a solid, a semisolid or a liquid at room temperature (preferably a boiling point of 100 ° C. or higher at atmospheric pressure, more preferably 150 ° C. or higher). Which is a substance which dissolves or melts in a binder upon heating, and is preferably a urea derivative (eg, dimethylurea, diethylurea, phenylurea, etc.), an amide derivative (eg, acetamide, benzamide, etc.), polyvalent Examples thereof include alcohols (for example, 1,5-pentanediol, 1,6-pentanediol, 1,2-cyclohexanediol, pentaerythritol, trimethylolethane, etc.) and polyethylene glycols. A detailed specific example is described in Japanese Patent Application No. 58-104249. These hot solvents may be used alone or in combination of two or more.

Also, Japanese Patent Publication No. 46-5393, Japanese Patent Laid-Open Nos. 50-54329 and 50-77034.
Post-treatment may be carried out using a sulfur-containing compound as described in each publication.

Furthermore, U.S. Pat.Nos. 3,301,678 and 3,506,444,
No. 3,824,103, No. 3,844,788 isothiuronium-based stabilizer precursor described in each specification, also U.S. Patent No. 3,669,670, No. 4,012,260, No. 4,060,42
The activator stabilizer precursor described in the specification No. 0 and the like may be contained.

Further, a water-releasing agent such as sucrose, NH ₄ Fe (SO ₂ ) ₂ · 12H ₂ O may be used, and further, as described in JP-A-56-132332, water is supplied for thermal development. Good.

In addition to the above components, the photothermographic material of the present invention may further contain various agents such as spectral sensitizing dyes, antihalation dyes, optical brighteners, hardeners, antistatic agents, plasticizers, and spreaders. Additives, coating aids, etc. are added.

The photothermographic material of the present invention basically contains (1) a photosensitive silver halide, (2) a reducing agent, (3) a dye-providing substance, and (4) a binder in the same layer, and further, if necessary. Accordingly, it is preferable to contain (5) an organic silver salt.

However, these do not necessarily have to be contained in a single photosensitive layer. For example, the photosensitive layer is divided into two layers, and the components (1), (2), (4), and (5) are contained on one side. It may be contained in two or more photosensitive layers as long as they can react with each other, such as being contained in the photosensitive layer and containing the dye-donor substance (3) in the layer on the other side adjacent to the photosensitive layer. .

In addition, the photosensitive layer may be divided into two or more layers such as a high-sensitivity layer and a low-sensitivity layer, and may have one or more photosensitive layers having different color sensitivities. Further, it may further have various constituent layers such as a protective film layer, an undercoat layer, a backing layer, an intermediate layer, or a filter layer.

Similar to the heat-developable photosensitive layer, a protective film layer, an intermediate layer, a subbing layer, a backing layer, each coating solution is prepared for other constituent layers, dipping method, air knife method, curtain coating method or U.S. Pat. The photosensitive material can be prepared by various coating methods such as the hopper coating method described in No.

Furthermore, if desired, two or more layers can be coated simultaneously by the methods described in US Pat. No. 2,761,791 and British Patent No. 837,095.

The above components used in the photosensitive layer of the photothermographic material of the present invention are coated on a support, and the thickness of coating is 1
The thickness is preferably 1,000 μm, more preferably 3 to 20 μm.

The photothermographic material of the present invention is exposed imagewise as it is,
Usually, color development is carried out only by heating in the temperature range of 80 ° C. to 200 ° C., preferably 120 ° C. to 170 ° C. for 1 second to 180 seconds, preferably 1.5 seconds to 120 seconds. Further, if necessary, a water-impermeable material may be brought into close contact with the surface for development, or preheating may be carried out at a temperature range of 70 ° C. to 180 ° C. before exposure.

Various exposing means can be used for the photothermographic material of the present invention. The latent image is obtained by imagewise exposure to radiation containing visible light. Generally, a light source used for ordinary color printing, for example, a tungsten lamp, a mercury lamp, a xenon lamp, a laser beam, a CRT beam or the like can be used as the light source.

As the heating means, all methods applicable to ordinary photothermographic materials can be used, for example, contact with a heated block or plate, contact with a heat roller or a heat drum, or passage through a high temperature atmosphere. Alternatively, high frequency heating may be used, or a conductive layer may be provided in the light-sensitive material of the present invention or in the image transfer layer (element) for thermal transfer, and Joule heat generated by energization or a strong magnetic field may be used. The heating pattern is not particularly limited, and it includes a method of preheating (preheating) in advance and then heating again, rising at a high temperature for a short time or at a low temperature for a long time, continuously rising, descending or repeating, and further discontinuous. Although heating is possible, a simple pattern is preferable. Further, it may be a system in which exposure and heating proceed simultaneously.

The photothermographic material of the present invention includes a so-called transfer type photographic material in which a dye formed on the photographic layer by heat development is transferred to the image receiving layer to form a color image, and can be preferably applied.

The heat-developable image-receiving layer may have a function of receiving a dye released or formed by heat development, and may be a mordant used in a dye diffusion transfer type photosensitive material or a glass transition described in JP-A-57-207250. It is preferably formed of a heat resistant organic polymer substance having a temperature of 40 ° C. or higher and 250 ° C. or lower.

Specific examples of the mordant, nitrogen-containing secondary, tertiary amines, nitrogen-containing heterocyclic compounds, these quaternary cationic compounds, U.S. Patent Nos. 2,548,564, 2,484,430, 3,4,
Vinyl pyridine polymers and vinyl pyridinium cation polymers disclosed in 148,061 and 3,756,814, polymers containing dialkylamino groups disclosed in U.S. Pat.No. 2,675,316, aminoguanidine derivatives disclosed in U.S. Pat. , JP-A-54-137
Covalently bonded reactive polymers described in U.S. Pat. No. 3,625,694, U.S. Pat. No. 3,859,096, British Patent 1,277,453.
Nos. 2,011,012 and mordants capable of crosslinking with gelatin and the like, U.S. Patent Nos. 3,958,995 and 2,721,852
No. 2,798,063 aqueous sol type mordant disclosed in JP-A-50-61228, water-insoluble mordant disclosed in US Pat. No. 3,788,855, West German patent application (OLS) No. 2,
843, 320, JP-A-53-30328, 52-155528, 53-1
No. 25, No. 53-1024, No. 54-74430, No. 54-124726, No.
55-22766, U.S. Pat.Nos. 3,642,482, 3,488,706,
The various mordants disclosed in No. 3,557,066, No. 3,271,147, No. 3,271,148, Japanese Patent Publication Nos. 55-29418, 56-36414, 57-12139, Research Disclosure 12045 (1974) may be mentioned. it can.

Particularly useful mordants are polymers containing ammonium salts,
It is a polymer containing a quaternary amino group described in US Pat. No. 3,709,690. Examples of the polymer containing an ammonium salt include polystyrene-co-N, N, N-tri-n-hexyl-N-vinylbenzylammonium chloride,
The ratio of styrene to vinylbenzylammonium chloride is 1: 4 to 4: 1, preferably 1: 1.

A typical image receiving layer for dye diffusion transfer is obtained by mixing a polymer containing an ammonium salt with gelatin and coating the mixture on a support.

An example of the heat-resistant organic polymer substance has a molecular weight of 2,000.
~ 85,000 polystyrene, polystyrene derivatives having substituents with 4 or less carbon atoms, polyvinyl cyclohexane, polyvinyl benzene, polyvinyl pyrrolidone, polyvinyl carbazole, polyallyl benzene, polyvinyl alcohol, polyvinyl formal and polyvinyl butyral and other polyacetals, polyvinyl chloride , Chlorinated polyethylene, polytrifluoroethylene, polyacrylonitrile, poly-N, N-dimethylacrylamide, p-cyanophenyl group, pentachlorophenyl group and 2,4-
Polyacrylate with dichlorophenyl group, polyacrylchloroacrylate, polymethylmethacrylate,
Polyethylmethacrylate, polypropylmethacrylate, polyisopropylmethacrylate, polyisobutylmethacrylate, poly-tert-butylmethacrylate,
Examples thereof include polyesters such as polycyclohexyl methacrylate, polyethylene glycol dimethacrylate, poly-2-cyano-ethyl methacrylate and polyethylene terephthalate, polysulfones, polycarbonates such as bisphenol A polycarbonate, polyanhydrides, polyamides and cellulose acetates. Also, Polymer Handbook 2nd ed. (J. Brandr
Synthetic polymers having a glass transition temperature of 40 ° C. or higher described in John Wiley & Sons, published by up, EHImmergut) are also useful. These polymeric substances, even when used alone,
Further, a plurality of them may be combined and used as a copolymer.

Particularly useful polymers include cellulose acetates such as triacetate and diacetate, heptamethylenediamine and terephthalic acid, fluorenedipropylpropylamine and adipic acid, hexamethylenediamine and diphenic acid, and polyamides by a combination of hexamethylenediamine and isophthalic acid, Examples thereof include polyester, polyethylene terephthalate, polycarbonate, and vinyl chloride, which are combinations of diethylene glycol and diphenylcarboxylic acid, bis-p-carboxyphenoxybutane and ethylene glycol, and the like. These polymers may be modified. For example, polyethylene terephthalate using cyclohexanedimethanol, isophthalic acid, methoxypolyethylene glycol, 1,2-dicarbomethoxy-4-benzenesulfonic acid or the like as a modifier is also effective. Of these, Japanese Patent Application No. Sho 58 is particularly preferable.
-97907, layer made of polyvinyl chloride and Japanese Patent Application No.
A layer composed of the polycarbonate and the plasticizer described in 58-128600 can be mentioned.

The above-mentioned polymer is dissolved in a suitable solvent and applied on a support to form an image-receiving layer, or a film-like image-receiving layer comprising the above-mentioned polymer is laminated on the support and used, or applied on the support. Alternatively, the member (for example, a film) made of the above polymer may be used alone to form the image receiving layer (also used as the image receiving layer support).

Further, the image receiving layer may be formed by providing an opaque layer (reflective layer) containing titanium dioxide dispersed in gelatin on the image receiving layer on a transparent support. With this opaque layer, a reflective color image can be obtained by viewing the transferred color image from the transparent support side of the image receiving layer.

[Specific effects of the invention] As described above, the photothermographic material of the present invention contains a modified polyvinyl alcohol-based polymer having excellent compatibility with gelatin and the like, and in particular, a binder of the photosensitive layer and, if necessary, Since it is contained in the provided intermediate layer, protective film, etc., it has good heat developability and dye permeability, and in the case of a transfer type, it has no transfer unevenness and is excellent in coatability during production.

When a modified polyvinyl alcohol-based polymer is contained in, for example, gelatin which constitutes the binder of the photosensitive layer, it is particularly excellent in heat developability and dye permeability and has good compatibility with gelatin, so that transfer unevenness does not occur. Further, when the modified polyvinyl alcohol-based polymer is contained in gelatin, which constitutes the intermediate layer, the dye permeability is particularly good. Further, when the protective film is formed, for example, when gelatin contains a modified polyvinyl alcohol-based polymer, it is particularly excellent in dye permeability and further has good compatibility with gelatin to form a uniform and non-sticky film during production. The transferability is also good.

[Examples] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these embodiments.

Example 1 22.7 g of benzotriazole silver and 400 ml of methyl alcohol,
Polyvinyl alcohol and each of the various water-soluble polymers shown in Table 1 were added with 500 ml of 8% aqueous solution and dispersed by a ball mill for 18 hours. Next, the silver iodobromide emulsion chemically sensitized while stirring this dispersion (5 mol% silver iodide, emulsion 1K)
An average particle size of 0.05 containing 60 g of gelatin and 0.353 mol of silver in 0.05 g
84 cubic particles). (Contains about 5.4 g of gelatin) 9 ml of 2% methanol solution of 3-amino-4-allyl-5-mercaptotriazole, 8.9 g of ascorbic acid
And 10 ml of 10% gelatin aqueous solution were mixed, 30 g of D-xylitol was further added, and the mixture was stirred well. The coating liquid thus prepared was applied onto baryta paper and dried to prepare samples 1 to 8.

Then, each sample was uniformly heated in a heat block at 130 ° C. for 20 seconds and thermally developed. The sensitivity, maximum concentration (Dmax), and minimum concentration (Dmin) of each sample are shown below.

The modified PVA shown in Table 1 was obtained as follows.

After adding 420 parts of distilled water to 100 parts of polyvinyl alcohol having a mercapto group at the end (saponification degree = 98.7 mol%, [HS] = 1.46 × 10 ⁻⁵ eq / g) and boiling to dissolve, cool to room temperature, pH was adjusted to 3.0 with 1N-H ₂ SO _4. Then, 10 parts of acrylic acid monomer was added and dissolved, and after nitrogen substitution, the temperature was raised to 70 ° C., and an initiator aqueous solution in which 0.38 part of K ₂ S ₂ O ₈ was dissolved in 20 parts of distilled water was added to carry out polymerization. Started. After stirring and polymerizing at 70 ° C. for 3 hours, the mixture was cooled to room temperature to obtain a polyvinyl alcohol-polyacrylic acid block copolymer aqueous solution. pH
Adjusted to 5.5, the concentration was 17.3%. The viscosity at 20 ° C was 4500 cp. Modified PV of this block copolymer
Notated as A (A).

The modified PVA (B) to (D) were prepared in the same manner as described below.
The composition, concentration and pH are summarized in Table 2.

From the results shown in Table 1, the sensitivity of the sample of the present invention [relative sensitivity (fog + 0.1) was measured by setting the sensitivity of sample 6 of the present invention to 100]. ] And the maximum density are both high, and the minimum density is low,
It can be seen that the present invention has good properties in heat developability.

Example-2 400 ml of 1% gelatin aqueous solution to 22.6 g of benzotriazole silver
Was added and dispersed by a ball mill for 18 hours, and a 7.2% gelatin aqueous solution was added to prepare a dispersion liquid.

The same benzotriazole silver 22.6g, methanol 400ml,
500 ml of an 8% polyvinyl alcohol (saponification degree 99.5%, viscosity average degree of polymerization 1750) aqueous solution was added, and ball mill dispersion was performed to prepare a dispersion liquid. Chemically resensitized silver iodobromide emulsions (4 mol% silver iodide, 60 g gelatin and 0.35 silver in 1 kg emulsion)
280 ml of cubic particles having an average particle size of 0.1 μm and containing 3 mol) were added.

Further, 8.2 g of p-amino-N, N-diethylaniline and 23.7 g of the following coupler (1) as a cyan dye-forming coupler.
Was dissolved in 10 g of di-n-butyl phthalate and 40 ml of ethyl acetate, mixed with 5 ml of 5% alkanol XC (manufactured by DuPont, trade name of sodium dialkylnaphthalene sulfonate) and 100 ml of 5% gelatin aqueous solution, and ultrasonically dispersed. . Further, 9 ml of a 2% aqueous solution of 3-amino-4-allyl-5-mercaptotriazole in methanol and 50 g of 50 g of 3-methylpentane-1,3,5-triol were added and well stirred.

The coating solution thus prepared was coated and dried on a polyethylene terephthalate base with gelatin subbing (3 μm dry film thickness) to obtain samples 9 and 10. Also PVA (saponification degree 99.5%,
Samples 11 to 17 in which the viscosity average degree of polymerization 1750) was changed to another water-soluble polymer as follows were prepared in the same manner.

Sample No. 9 Gelatin 10 PVA117 (Kuraray, saponification degree 98.5%, degree of polymerization 1750) 11 PVA105 (Kuraray, saponification degree 98.5%, degree of polymerization 550) 12 PVA217 (Kuraray, saponification degree 88.0%, degree of polymerization 1700) 13 S-REC w-201 (manufactured by Sekisui Chemical, butyralization degree 1
1%, degree of polymerization 650) 14 Polyvinylpyrrolidone k-30 (Tokyo Kasei, degree of polymerization
40000) 15 Modified PVA (A) 16 Modified PVA (C) 17 Modified PVA (D) All of the above samples are Gel: Water-soluble polymer = 2 by weight ratio.
2:40.

Separately, on a photographic baryta paper, a 5% tetrahydrofuran solution of polyvinyl chloride was added to 1.20 g of polyvinyl chloride per 1 m ^2.
To obtain an image-receiving paper.

After exposing samples 9 to 17 with wedges, they were brought into close contact with the image receiving paper,
Thermal development and thermal transfer were carried out for 0 seconds. The results are shown in Table 3.

In addition, these samples 9 to 17 under the conditions of 28 ℃, 70% relative humidity
After storing for 30 minutes, the sample No. 14 was particularly sticky and could not be overlaid.

From the results shown in Table 3, it can be seen that the present invention exhibits favorable properties in heat developability, dye permeability and transferability.

Example-3 In Example-2, benztriazole silver was added to 32.8 g of sulfobenztriazole (Na salt) silver, and p-amino-
Example except that N, N-diethylaniline was replaced by 17.3 g of p-N, N-diethylaminophenylsulfamate sodium salt-
A sample was prepared in exactly the same manner as 2 and the same comparison was performed. The results are shown in Table 4.

No stickiness was observed in all samples under the same conditions as in Example-2.
No. 3 could not overlap the samples.

Example-4 Silver iodobromide emulsions chemically sensitized using the same nine kinds of dispersions as in Example-2 (4 mol% of silver iodide, 60 g of gelatin and 0.353 mol of silver in 1 kg of emulsion) 280 ml of cubic particles having a particle size of 0.1 μm) were added.

Further, 53.7 g of the magenta dye-donating substance (1) represented by the following structure, 50 g of tricresyl phosphate and 150 ml of ethyl acetate are added, and the mixture is heated and dissolved at about 60 ° C. to form a uniform solution. 15 ml of this solution and 5% alkanol XC aqueous solution and 5%
What was mixed with 300 ml of gelatin aqueous solution and ultrasonically dispersed was added. Further, 20 ml of a 5% aqueous solution of the following compound (1) and 5.0 g of the following compound (2) were added and well stirred. The coating solution thus prepared was coated on a polyethylene terephthalate base with a gelatin subbing (thickness of 3 μm) and dried to obtain a sample.
27 to 35.

Compound (2) H ₂ N-SO ₂ -N (CH ₃ ) ₂ or poly (methyl acrylate-co-N, N, N-) as an image receiving layer
10 g of trimethyl-N-vinylbenzylammonium chloride) (the ratio of methyl acrylate and vinylbenzylammonium was 1: 1) was dissolved in 200 ml of water and uniformly mixed with 100 g of gelatin. This mixed solution was uniformly applied on polyethylene terephthalate in which titanium dioxide was dispersed to a wet film thickness of 90 μm. On top of this, the following composition 2
The second layer was uniformly applied so as to have a wet film thickness of 60 μm and dried.

Urea 20g N-methylurea 20g Water 80ml Guanidinium trichloroacetic acid 4g Polyvinyl alcohol (PVA117 saponification degree 98%, average degree of polymerization 1750) 10% aqueous solution 120ml Emulgen 908 5% aqueous solution 20ml Sodium dodecylbenzenesulfonate 5% aqueous solution 5ml This After the sample is dried, it is used as an image receiving material.

The above-mentioned light-sensitive materials No. 27 to 35 were exposed to wedges, then overlapped with the image-receiving material and heated at 140 ° C. for 60 seconds, and then the image-receiving material was peeled from the light-sensitive material. The results are shown in Table 5.

As described above, it can be seen that the present invention has a high Dmax value. As in Examples 1 to 3, the sample No. 32 was particularly sticky and could not be overlaid.

Example-5 To 32.8 g of silver sulfobenztriazole (Na salt), 400 ml of methanol and 500 ml of an 8% polyvinylpyrrolidone (K-30) aqueous solution were added and dispersed by a ball mill for 18 hours. Next, this dispersion was chemically sensitized while stirring the emulsion (4 mol% of silver iodobromide, 60 g of gelatin and 0.
280 ml of cubic particles with an average particle size of 0.1 μm containing 353 mol (G
el 17g), and p-N, N-diethylaminophenylsulfamate sodium salt 17.3g were added, and coupler (2) 23.7g represented by the following structural formula was added to n-dioctyl phthalate 1
0g, dissolved in 60 ml of ethyl acetate, alkanol B 5% aqueous solution
5 ml and 100 ml of 5% gelatin aqueous solution, mixed and ultrasonically dispersed, were added. Furthermore, 3-amino-4-allyl-5-
2% methanol solution of mercaptotriazole 9ml, 50g
50 g of 3-methylpentane-1,3,5-triol was added and stirred well. The coating solution thus prepared was coated and dried on a polyethylene terephthalate base having a gelatin subbing (coating amount of 3 g / m ² ) so that the amount of silver was 1 g / m ² . Then, a protective film having the following composition was dried on it at 3 g / m ²
Sample Nos. 36 to 43 were prepared by coating so that the coating amount becomes.

No.36 is the same gelatin protective film as normal photosensitive materials, No.37-
No. 39 uses a typical synthetic water-soluble polymer alone as a protective film, and Nos. 40 to 43 use gelatin and a mixture of these typical water-soluble polymers as a protective film. Nos. 37 to 39 are coating liquids that do not contain gelatin, so the film flows slightly after coating and becomes non-uniform.
Nos. 36, 40, 41, 42 and 43 were evenly applied.

In addition, polyvinyl chloride (n = 1,10
0, manufactured by Wako Pure Chemical Industries, Ltd.) was applied as a tetrahydrofuran solution to form an image receiving layer so that the dry film thickness of the polyvinyl chloride layer would be 10 μm.

Each of Sample Nos. 36 to 43 described above was overlapped with the image receiving element after wedge exposure, and uniformly heated at 150 ° C. for 30 seconds to be peeled off. The results are shown in Table 6.

Also, the stickiness of the surface of the photosensitive material when stored under conditions of 28 ° C. and 70% relative humidity is: ○ not very sticky, △ slightly sticky,
× It was evaluated as being extremely sticky and the photosensitive material could not be overlaid. From the above results, it is understood that the sample of the present invention has excellent coatability, excellent dye permeability, little surface tackiness, and good properties as a protective film.

Example-6 Instead of the coupler of Example-5, 23.7 g of a coupler (3) represented by the following structural formula and 10 g of di-octyl phthalate were used.
50 g of 3-methylpentane-1,3,5 as a hot solvent
-The one using triotyl is E, the one using D-xylinal in place of it is F, the one using N, N'-dimethylurea is G, the one using 1,5-pentanediol is H. did.

Samples E-1, F-1, G-1, and H- were prepared by applying a binder and a thermal solvent having the same composition ratio as that of the photosensitive layer on the sample.
It was set to 1. Also, modified PVA instead of polyvinylpyrrolidone
Those using (A) and (B) are E-2 and E-, respectively.
3, F-2, F-3, G-2, G-3, H-2, H-3
(Binder coating amount 3 g / m ² ). E-1, F-1,
G-1 and H-1 were so sticky that they could not be superposed on each other when stored at 28 ° C. and 70% relative humidity. F-2 to H-2 and F-3 to H-3 were good without stickiness. After exposure of each of these samples, they were combined with the image-receiving layer and subjected to heat development in the same manner as in Example-5.
The results are shown in Table 7.

Table 7 Sample No. Dmax Remarks E-1 1.68 Comparison F-1 1.28 〃 G-1 1.70 〃 H-1 1.60 〃 E-2 1.70 Present invention F-2 1.31 〃 G-2 1.68 〃 H-2 1.65 〃 E-3 1.65 〃 F-3 1.25 〃 G-3 1.66 〃 H-3 1.60 〃 Samples E-1, F-1, G-1, and H-1 have high density but are films at the time of heat development Scratch (crush) was large and uneven transfer was observed.

Protective film composition E-1,2,3 Gel / Polymer / 3-methylpentane-1,3,5-
Triol = 22/40/50 F-1,2,3 Gel / Polymer / D-xylitol = 22/40/50 G-1,2,3 Gel / Polymer / N, N'-dimethylurea =
〃 H-1,2,3 Gel / Polymer / 1,5-Pentanediol =
It can be seen that in the present invention, by using the modified PVA as the protective film, it is possible to obtain a good light-sensitive material having good dye permeability and being less sticky even when the thermal solvent is changed.

Example-7 Red-sensitive silver halide emulsion (silver iodide content 4 mol%, chemically ripened silver iodobromide emulsion having a grain size of 0.1 μm was added to 3,3′-di-
0.2 g of (γ-sulfopropyl) -9-methylthiadicarbocyanine sodium salt added at 600 mg per mol of silver) was converted to silver in an aqueous poly (4-vinylpyrrolidone) solution. 0.2g of 3-methylpentane-1,3,5-triol, 1.6g of 4-diethylamino-2-methylphenylsulfamine was calculated by converting equimolar amounts of triazole and silver nitrate to pH 6.0 and converting to silver. 0.4 g of acid soda, 2-acetamido-4- (1-carboxy-tridecyloxy)-
A coating solution containing 0.52 g of 5-methyl-6-chlorophenol and 6 mg of 3-amino-4-allyl-5-mercapto-1,2,4-triazole, and additional gelatin, a surfactant and a gelatin hardener. Photographed thickness
It was coated on a 100 μm transparent polyethylene terephthalate film. The coating amount of silver, gelatin and poly (4-vinylpyrrolidone) is 1.2 g / m ² , 1.25 g / m ² and 2.9 g / m ² , respectively.
It was m ² . Then, an intermediate layer made of the following polymers was provided as an intermediate layer.

The coating amount of the intermediate layer was 1 g / m ² in total of the binder and contained 0.7 g / m ^{2 of} 3-methylpentane-1,3,5-triol. Furthermore, the red-sensitive silver halide emulsion was further coated thereon with a green-sensitive silver halide emulsion (silver iodide content 4 mol%, average grain size).
0.125 μm, cubic grains of chemically ripened silver iodobromide emulsion with 3,3′-carboxyethyl-1,5′-dichloro-oxacarbocyanine added at 500 mg per silver mole)
In place of α-benzoyl-α- [1
-Phenyl-2- [4- {2-octadecenyl-3-carboxypropane-amido} benzyl] -1,2,4-triazolidine-3,5-dione-4-yl-]-2-chloroacetanilide to 0.65 g The same coating liquid was applied on this in the same manner except that it was replaced, and each sample was applied to the intermediate layers No. 1 to 7.
It corresponds to 44 to 50. Each sample was exposed to red light, and after overlapping with the image-receiving paper prepared in Example 5, heat development and heat transfer were performed. The results are shown in Table 8.

Sample No.44 has extremely poor dye permeability, and Sample No.4
5,46,48 had uneven transfer. In contrast, the sample of the present invention has a high transfer density and does not cause transfer unevenness.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ken Iwagaki 1 Sakura-cho, Hino-shi, Tokyo Konishi Roku Photo Industrial Co., Ltd. (72) Toshiaki Sato 1621 Sakata, Kurashiki-shi, Okayama Kuraray Co., Ltd. (72) ) Inventor Junnosuke Yamauchi 1621 Sakurazu, Kurashiki City, Okayama Prefecture Kuraray Co., Ltd. (72) Inventor Takuji Okaya 1621 Sakata Tsu, Kurashiki City, Okayama Prefecture (56) Reference JP-A-59-178456 (JP, Sho A)

Claims (1)

[Claims] 1. A photothermographic material having a photosensitive layer containing at least silver halide grains on a support, wherein the photosensitive material comprises a polymer containing a polyvinyl alcohol polymer as a component and having an ionic group. Having a layer containing a water-soluble or water-dispersible block copolymer as another component, the weight ratio of the polyvinyl alcohol polymer to the polymer having the ionic group is 0.2 or more and 50 or less. Characterized photothermographic material.