JPH06167792A - Heat developable photosensitive material - Google Patents

Abstract

PURPOSE:To provide a heat developable photosensitive material which forms a black and white dyestuff image by forming or releasing the diffusive dyestuff image by heat development and transferring this image to an image receiving layer, forms the black image hardly deteriorated in neutral characteristic even by a difference in the density of the transferred image, has the good white ground after the transfer and forms the black and white image suppressing the increase in stains even when preserved under high-temp. conditions,. CONSTITUTION:The polymer dyestuff donative material of the heat developable photosensitive material contg. a photosensitive silver halde emulsion, binder and the polymer dyestuff donative material forming or releasing the diffusive dyestuff at the time of heat development on a base is the polymer dyestuff donative material having the repeating units derived from at least two kinds of the dyestuff donative material monomers forming or releasing the diffusive dyestuff having the color tones substantially different from each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photothermographic material, and more particularly to a photothermographic material which transfers a diffusible dye to an image receiving layer to form a black and white image.

[0002]

BACKGROUND OF THE INVENTION A thermal development process in which a development process is performed by heating is known, and a process for obtaining a monochrome image and a color image is known. Further, a so-called transfer type photothermographic material is also well known, which transfers an image obtained by heat development from the photosensitive material to the image receiving layer.

The heat-developable light-sensitive material usually has a binder, a light-sensitive silver halide emulsion, a reducing agent, and, if necessary, a dye-donor substance, an organic silver salt and various other photographic additives on a support. is doing. Further, in the transfer type photothermographic material, the above-mentioned image receiving material having an image receiving layer capable of receiving silver or a dye, and an image receiving material having an image receiving layer capable of receiving a silver or a dye separately from the photosensitive material. May be used together.

Many conventional dry thermal development methods have been known in which a color image is obtained by simply heating a silver halide photographic light-sensitive material.

For example, JP-A-57-186744 discloses a photothermographic material which releases a diffusible dye image by binding with an oxidant of a reducing agent produced by a reaction between a reducing agent and an organic silver salt oxidizing agent. Is listed.

For example, JP-A-58-58543 describes a photothermographic material containing a dye-donor substance that releases a dye that is reducing and diffusible with an organic silver salt oxidizing agent. There is.

For example, JP-A-59-180548 describes a photothermographic material that releases a diffusible dye by causing a cleavage reaction of a heterocycle containing a nitrogen atom and a sulfur atom in the presence of silver ions. ing.

For example, JP-A-60-2950 describes a heat development method for forming a diffusible dye image by a coupling method using a specific polymer coupler and a p-phenylenediamine color developer precursor. There is.

For example, JP-A-60-244947 describes a photothermographic material containing an oxidative dye-providing substance which releases a quinometide type diffusible dye.

In each of the above photothermographic materials, a diffusible dye image is formed or released during heat development.
These are preferably transferred to the dye image-receiving layer under heating to obtain a clear image.

On the other hand, obtaining a black-and-white image by heat development has also been performed for a long time, and is usually achieved by forming an image of silver by heat development, which is put to practical use in "Dry Silver" of 3M Company. Has been done. However, in this method, unused silver halide and organic silver salt remain in the image area even after development, so that there is a problem that the white background portion is gradually colored (printed out) during storage of the image. .

In order to solve the problem of printout, a diffusible dye is conventionally formed during heat development,
Several proposals have been made to transfer this to an image receiving layer to obtain a black and white image.

Japanese Unexamined Patent Publication (Kokai) No. 60-66249 discloses a diffusion transfer type photothermographic material which forms or releases a diffusible black dye during heat development and transfers it to an image-receiving layer to form a black and white image. .

JP-A-60-162251 discloses heat development in which an image dye capable of obtaining a substantially black image is produced or released by heat development and this dye is transferred to a dye fixing layer to form a black and white image. A light sensitive material is disclosed. And, from the description of the specification, a description preferably carried out by containing a yellow dye-releasing substance that releases a yellow dye, a magenta dye-donor substance that releases a magenta dye, and a cyan dye-donor substance that releases a cyan dye in combination. There is.

JP-A-3-296746 discloses that the maximum absorption wavelength is 57
Heat for black-and-white image formation using a combination of two kinds of dye-donor which forms or emits a dye in the range of 0 to 610 nm and dye-donor which forms or releases a dye in the maximum absorption wavelength of 470 to 520 nm Developing light-sensitive materials are described.

JP-A-4-147254 discloses a photothermographic material containing yellow, magenta and cyan dye-donor substances and limiting the molecular weight of diffusible dyes formed or released from the dye-donor substances to a specific range. Is listed.

However, the black-and-white photothermographic material obtained by transferring various dye images described above has various drawbacks.

In the diffusion transfer type photothermographic material described in JP-A-60-66249, a diffusible black dye is formed or released at the time of thermal development and transferred to an image receiving layer to form a black and white image. It cannot be said that the black dye to be obtained has sufficient neutrality, and the dye-donor substance is transferred to the image-receiving layer to deteriorate the white background or the image-receiving layer after transfer is stored under high temperature conditions. In this case, there is a drawback that stains are easily generated. In the case of a photothermographic material containing yellow, magenta and cyan dye-donor substances described in JP-A-60-162251, a difference in the density of the transferred image tends to cause a difference in neutrality, resulting in a low density. There was a problem that it was difficult to obtain stable neutrality from high to high concentrations.

When the dye-donor substance is a polymer, in addition to this, the polymerization conditions of the polymer influence the rate at which the diffusible dye is formed or released, and the mixing ratio must be changed for each production lot. There is a problem of not becoming.

As described in JP-A-3-296746, a dye-donor which forms or emits a dye having a maximum absorption wavelength in the range of 570 to 610 nm and a dye having a maximum absorption wavelength in the range of 470 to 520 nm are formed. Also, a black and white image forming photothermographic material using a combination of two types of releasing dye-providing substances has the same problem as described above.

All of the above points are caused by the fact that the dye-donor substances are mixed and used, which brings about a subtle difference in the stability and the dye formation rate between the dye-donor substances having different compositions. I think

[0022]

SUMMARY OF THE INVENTION In order to solve the above problems, the first object of the present invention is to form or release a diffusible dye image by heat development and transfer it to an image receiving layer to form a black and white dye image. It is an object of the present invention to provide a heat-developable light-sensitive material which gives a black image in which the neutrality is hardly deteriorated even by the difference in the density of the transferred image.

A second object of the present invention is to provide a photothermographic material which has a good white background after transfer and which can form a black and white image with suppressed increase in stain even when stored under high temperature conditions. Especially.

[0024]

The above object of the present invention is to provide a photothermographic material containing on a support a light-sensitive silver halide emulsion, a binder, and a polymer dye-donor substance which forms or releases a diffusible dye during heat development. The polymer dye-donor is a polymer dye-donor having repeating units derived from at least two dye-donor monomers that form or release diffusible dyes having substantially different tones. And a photothermographic material.

The structure of the present invention will be specifically described below.

The polymer dye-donating substance used in the photothermographic material of the invention is obtained by copolymerizing at least two kinds of dye-donor substance monomers which form or release diffusible dyes having substantially different color tones. It is a dye-providing substance.

The term "substantially different in color tone" as used herein means that a color tone that is substantially neutral can be formed when a diffusible dye released or formed from the polymer dye-donor is combined. Is different, and changes depending on the spectral absorption characteristics of each diffusible dye (λmax, full width at half maximum, secondary absorption, etc.), but preferably the maximum absorption wavelength at 400 to 700 nm is at least 50 nm. There are differences.

The polymer dye-donating substance of the present invention is obtained by copolymerizing at least two or more monomers of the dye-donating substance which form or release diffusible dyes having substantially different color tones during thermal development. The upper limit is not particularly limited as long as it is 2 or more, and it may be copolymerization of 3, 4 or 5 kinds of dye-donor monomers. However, in practice, copolymerization of 2 or 3 kinds of dye-donor monomers is preferably used in terms of cost.

The polymer dye-donating substance of the present invention is a copolymer with a monomer that does not form or release a diffusible dye during thermal development, in addition to the above-mentioned dye-donor substance monomer.
It is preferable in the dispersibility of the polymer dye-donor.

Such a monomer is a monomer having one or more kinds of polymerizable ethylenically unsaturated groups, and examples of the monomer having such an ethylenically unsaturated group include: For example, vinyl esters (eg, vinyl acetate, vinyl butyral, etc.), vinyl amides (eg, acrylamide, N-butyl acrylamide, etc.), acrylic acid or methacrylic acid derivatives (eg, acrylic acid, methacrylic acid, butyl acrylate, ethyl methacrylate,
2-hydroxyl ethylmethacrylate etc.), olefins (eg ethylene, propylene, butadiene etc.), vinyl aromatics (eg styrene etc.), N-vinylphthalamide, N-vinylpyrrolidone and other polymerizable compounds known in the art. The ethylenically unsaturated compound of can be mentioned.

The above-mentioned polymer dye-donating substance of the present invention is preferably a polymer derived from two types of dye-donor substance monomers represented by the above-mentioned general formula (1) (2) A polymer derived from the monomers of the three kinds of dye-donor substances represented by (Chemical Formula 2) is preferable.

In the general formula (1) or the general formula (2), the alkyl group represented by R ₁ , R ₂ , R ′ ₁ , R ′ ₂ and R ′ ₃ preferably has 1 to 18 carbon atoms. And an alkyl group having 1 to 4 carbon atoms is particularly preferable.

In the general formula (1) or (2), the linking groups represented by J ₁ , J ₂ , J ' ₁ , J' ₂ and J ' ₃ are diffusible dyes at the time of thermal development. It depends on the mechanism of formation or release.

The groups represented by D ₁ , D ₂ , D' ₁ , D' ₂ , and D' ₃ have a dye moiety, and J ₁ , J ₂ , J ' ₁ , J'during thermal development. _2, and if detached from J _'3,
The monomer of the dye-donor substance constituting the general formula (1) or the general formula (2) is preferably a monomer represented by the following general formula (3a) or (3b).

General formula (3a) R _3a -SO ₂ -D General formula (3b) R _3b -L _3b -D Among the groups represented by general formulas (3a) and (3b), D
Is D ₁ , D ₂ in the general formula (1) or the general formula (2),
It is synonymous with D' ₁ , D' ₂ , and D' ₃ .

R _{3a in the} general formula (3a) represents a group that can be oxidized during thermal development, and is a reducing group that can be oxidized in the process of reducing the silver ion of an organic silver salt or a photosensitive silver halide to a silver atom. is there. Preferable reducing groups represented by R _3a are, for example, JP-B-62-14823, page 4, column 8, line 21 to page 5, 9
The reducing groups represented by the general formulas (II) to (IX) described in the 40th line of the column are preferably used.

R _{3b in the} general formula (3b) is a group which is bonded to the oxidant of the reducing agent formed by the redox reaction between the reducing agent contained in the photothermographic material and the organic silver salt, and is preferably p -A group capable of binding to an oxidation product of an aminophenol-based or p-phenylenediamine-based reducing agent, and is described, for example, in JP-B-62-14822, page 4, column 8, line 20 to page 5, column 10, line 8. It is a group that has been

L _{3b in the} general formula (3b) represents a linking group of R _3b and D, and the bond between R _6b and L _6b is cleaved during the reaction with the oxidant of the reducing agent.

Preferred L _3b is, for example, Japanese Patent Publication No. 62-1.
No. 4822, page 8, column 15, line 16 to page 9, column 18, line 15 can be mentioned.

The reducing agent used with the dye-providing substance represented by the general formula (3b) of the present invention is a group whose oxidant can be bonded to the dye-providing substance, and is preferably the one represented by the general formula (5) described later. It is a color developer or a color developer precursor represented.

On the other hand, D ₁ , D ₂ , D' ₁ , D' ₂ , and D' ₃
When the group represented by the formula (3) is bonded to the oxidized form of the reducing agent at the active site and is separated from J ₁ , J ₂ , J ' ₁ , J' ₂ and J ' ₃ to form a diffusible dye, The monomer of the dye-providing substance constituting the formula (1) or the general formula (2) is preferably a monomer represented by the following general formula (3c).

[0042] R ₂₀ in the general formula _{(3c) CH 2 = C (} R 20) -J 20 -Cp general formula (3c) is a hydrogen atom or an alkyl group, the alkyl group is preferably a number of 1 to 6 carbon atoms Is an alkyl group (eg, methyl group, ethyl group, etc.). J ₂₀ is preferably represented by the following general formula (6a).

In the general formula (6a), J ₂₁ is -O - - [0043] Formula _{(6a) -J 21 - (Y} ) m20 -P 20, - COO-,
-OCO -, - CONH -, - C 6 H 4 -, or represents a single bond.

Y represents an alkylene group, an arylene group, an aralkylene group, an alkylenearylene group, an arylenearylene group or an aralkylenearylene group.

P20 is -O-,-in relation to Cp.
S-, -OCOO-, (Cp) -OCONH-, (C
p) -OCO-, -N = N-, (Cp) -NHCO-,
_{(Cp) -NHSO 2 -, (} Cp) -O-SO 2 -, (C
p) -O-CH (COOR ')-, and

[0046]

[Chemical 3]

Represents m20 represents 0 or 1.

R'represents a hydrogen atom, an alkyl group or an aryl group. Q'represents a non-atom group necessary for forming a 5- or 6-membered nitrogen-containing heterocycle.

Cp is preferably the following general formula (6b),
It is represented by (6c), (6d), (6e), (6f), (6g) or (6h).

[0050]

[Chemical 4]

In the formula, Rp, Rq, Rs and Rt are a hydrogen atom, a halogen atom, a nitro group, a sulfo group, a carboxyl group, a hydroxyl group, a cyano group, a substituted or unsubstituted alkyl group, a cycloalkyl group and an alkenyl group, respectively. Base,
Cycloalkenyl group, alkoxy group, aryloxy group, aryl group, acyl group, acylamino group, amino group, alkylsulfonyl group, arylsulfonyl group, alkylsulfonylamino group, arylsulfonylamino group, hydroxylalkyl group, alkoxycarbonyl group, aryl A substituent selected from an oxycarbonyl group, an alkylcarbonyloxy group, an arylcarbonyloxy group, an alkoxyalkyl group, a sulfamoyl group, a carbamoyl group, an N-substituted carbamoyl group, an N-substituted sulfamoyl group, an alkylthio group and an arylthio group. Represents

The monomer represented by the general formula (3a) is described, for example, in JP-A-62-65037, and can be easily synthesized according to the synthetic method described therein.

Specific examples thereof include the following monomers.

[0054]

[Chemical 5]

In addition to the above, for example, the exemplified monomers (m-1) to (m) described in JP-A-62-65037, page 7, upper right column to page 8, upper left column.
-12) can also be used in the present invention.

The monomer represented by the general formula (3b) is described, for example, in JP-A-61-210349 and 61-210351, and specific examples thereof include the following monomers. You can

[0057]

[Chemical 6]

[0058]

[Chemical 7]

[0059]

[Chemical 8]

In addition to the above, for example, JP-A-61-210351 11
Exemplified Monomers (1) to (25) on pages 13 to 13 and JP-A-61
-210349, Exemplified compounds (4), (6), and
(8), (10), (11) and (13) can also be used in the present invention.

Examples of the monomer represented by the general formula (3c) include, for example, Japanese Examined Patent Publication Nos. 3-60419, 1-40973, and 1-3533.
No. 4, No. 3-74818, No. 2-9333, No. 2-9332, JP-A-62
-129851, 63-38935, JP-A-2-300744, 3-397
No. 40, No. 3-67253, No. 3-67254, No. 3-67255, No. 3-1
Nos. 42449 and 3-296746, and specific examples thereof include the following compounds.

[0062]

[Chemical 9]

[0063]

[Chemical 10]

[0064]

[Chemical 11]

[0065]

[Chemical 12]

Besides the above, each monomer described in each of the above publications can be used in the present invention.

Next, a method for synthesizing the polymer dye-donor of the present invention using the above-mentioned monomer will be described.

The above-mentioned polymer dye-donating substance of the present invention is preferably a copolymer having at least one repeating unit which does not form or release a diffusible dye during thermal development, as described above. Examples of the monomer constituting the unit include acrylic acid esters, methacrylic acid esters, vinyl esters, acrylamides, methacrylamides, vinyl ethers, olefins, styrenes, acrylic acids, methacrylic acids,
There are itaconic acids, maleic acids, and the like. In particular,
The monomers described in JP-A-62-260152 may be mentioned.
Among them, acrylic acid esters (for example, butyl acrylate, ethyl acrylate, etc.), methacrylic acid esters (butyl methacrylate, octyl methacrylate, etc.), and styrenes are preferable.

The polymer dye-donating substance of the present invention may be one polymerized by a known emulsion polymerization method or solution polymerization method. Emulsion polymerization methods are described, for example, in US Pat.
No. 0,211 and 3,370,952 are polymerized by the method described in US Pat. No. 3,451,820, and a lipophilic polymer is dispersed in a hydrophilic colloid aqueous solution such as gelatin in the form of a latex. You can also

Examples of emulsifiers used in the emulsion polymerization method include surfactants, polymeric protective colloids, and copolymer emulsifiers. As the surfactant, known anions, cations, and amphoteric surfactants can be used.

On the other hand, when the polymerization is carried out by the solution polymerization method,
Solution polymerization is carried out in the presence of a polymerization initiator in a good solvent for the polymer monomer to be solution polymerized. As a good solvent for the polymer monomer, water, toluene, alcohols, acetone, methyl ethyl ketone, tetrahydrofuran, dioxane,
Examples thereof include dimethylformamide, ethyl acetate, dimethylsulfoxide, acetonitrile and methylene chloride, and an appropriate solvent is appropriately selected from these to perform polymerization. These solvents may be used alone or in combination of two or more.

The polymerization temperature varies depending on the type of polymerization initiator, the type of solvent used, etc., but is generally 30 to 120 ° C.

The polymerization initiator used in the emulsion polymerization method and solution polymerization method of the polymer dye-donating substance of the present invention includes
For example, the following can be mentioned.

Water-soluble polymerization initiators; persulfates (potassium persulfate, ammonium persulfate, etc.), water-soluble azo compounds (4,
4'-azobis-4-cyanovalerate sodium, 2,2'-azobis (2-aminopropane) hydrochloride, etc.) Hydrogen peroxide lipophilic polymerization initiator; azo compound (azobisisobutylnitrile, 2,2'- Azobis- (2,4dimethylvaleronitrile), 2,2'-azobisisocyanobutyric acid, etc. Peroxides (benzoyl peroxide, lauryl peroxide, chlorobenzyl peroxide, etc.) These polymerization initiators are emulsion polymerization methods. And in the solution polymerization method, it is used in the range of 0.01 to 10% by weight, preferably 0.1 to 5% by weight, based on the total amount of the monomers.

More specific examples of polymerization of the polymer dye-donating substance of the present invention are described in, for example, Japanese Patent Publication No. 1-35334 or US Pat. No. 5,141,844, which can be easily synthesized with reference to these. .

Synthesis Example-1 Synthesis of Exemplified Polymer PC-4 Exemplified Monomers 3c-1 (2 mol), 3c-4 (1 mol), 3c
-9 (1.4 mol) and BA (5.6 mol) in 10000 ml D
It was dissolved in MF and heated to 80 to 82 ° C while introducing nitrogen gas. While maintaining this temperature, 60 g of 2,2′-azobisisobutyronitrile was added and the reaction was carried out for 4 hours. After the reaction was completed, the reaction solution was poured into 100 l of water and the precipitate was filtered off.
This precipitate was dissolved in ethyl acetate, dried over magnesium sulfate, and filtered. The filtrate was concentrated to dryness to obtain the target polymer.

The polymer dye-donor material of the present invention is preferably a copolymer of two or three kinds of dye-donor material monomers that form or release a diffusible dye during thermal development. Those obtained by copolymerizing the monomers of the three kinds of dye-providing substances represented by the general formula (2) are particularly preferable.

In the general formula (2), the molar ratios of p, q and r are the spectral absorption characteristics of the dye formed or released from each repeating unit, the maximum wavelength, the molecular absorption coefficient at the maximum wavelength, and the diffusible dye. It depends on the efficiency of formation or release. These conditions largely depend not only on the structure of the dye to be used but also on the constitution of the entire photothermographic material and the heat development conditions (temperature, time, etc.), and are set to optimum conditions in consideration of them. .

The optimum condition is that the black color of the transferred image is JIS-Z-8720.
Image color is JIS-Z-8729 based on standard light source C
By adjusting the molar ratio of each monomer so that a * and b * obtained from tristimulus values in the 10-degree visual field XYZ system become a * = 10 to -18 and b * = 10 to -18. S in the general formula (2) is an optimum value from the viewpoint of solubility and dispersion stability in low boiling point organic solvents (ethyl acetate, acetone, methyl ethyl ketone, etc.) that are preferably used when dispersing the polymer dye. Is selected, but usually 0.2
~ 0.8 is preferably used.

Next, Table 1 shows specific examples of the polymer dye-providing substance of the present invention.

In the table, Monomers-1, 2 and 3 each represent a monomer dye-donor of the present invention which releases or forms a diffusible dye at the time of thermal development. It represents the molar ratio to the total amount. The copolymerization monomer represents a monomer that does not release or form a diffusible dye at the time of heat development and is represented by the following abbreviations.

BA: n-butyl acrylate BMA: n-butyl methacrylate ST: styrene MMA: methyl methacrylate

[0083]

[Table 1]

The polymer dye-donating substance of the present invention preferably has a number average molecular weight of 5,000 or more from the viewpoint of diffusion resistance.
Particularly preferably, 10000 or more is used. Also,
The component having a molecular weight of 2000 or less is preferably 5% by weight or less.

The heat-developable light-sensitive material of the present invention forms or releases a single diffusible dye during heat development for the purpose of correcting variations in polymerization of the polymer dye-donor substance, in addition to the polymer dye-donor substance. It is preferable to contain a dye-providing substance that

The color-forming property or dye-releasing property of the copolymerized polymer is peculiar to the polymerization lot, and a slight difference inevitably occurs between the synthetic lots. In order to correct the difference in color tone between lots, it is very difficult in actual production to change the constituent conditions of the photothermographic material other than the dye-providing substance or to change the heat development conditions.

In order to correct such a variation in performance between lots in advance, a dye-donor substance (hereinafter referred to as a correction dye-donor substance) that forms or releases a minimum amount of a single diffusible dye is used. It is preferable to use it in order to stabilize the quality in manufacturing.

The number of such correction dye-donating substances may be one or two, but normally one type is generally sufficient because variations in performance are originally reduced. Of course, it is optional to change the correction dye-donor substance to be added between polymerization lots of the polymer dye-donor substance.

The amount of the correction dye-providing substance added is 0.1 to 10 mol%, preferably 0.2 to 5 mol% based on the total molar amount of the dye-donor substance monomers contained in the polymer dye-providing substance.
Is the range. The above-mentioned correction dye-donor substance may be a non-polymer because the amount thereof added is small, but a polymer dye-donor substance is preferred. Further, as a matter of course, the polymer dye-donor substance and the correction dye-donor substance form or release a diffusible dye by the same thermal development reaction system.

The above-mentioned correction dye-providing substance can be appropriately selected and used from the known dye-providing substances for photothermographic materials, and Table 2 shows specific examples thereof.

In the table, the numerical value in the parentheses represents the molar ratio of copolymerization. The abbreviations of the copolymerization monomers are the same as those in Table 1.

[0092]

[Table 2]

Other than the above, examples of the polymer-correcting dye-providing substance include, for example, JP-A-62-65037 and 61-210349.
No. 61-210351, Japanese Kokoku 3-60419, 1-40973,
1-35334, 3-74818, 2-9333, 2-9332,
JP-A-62-129851, JP-A-63-38935, JP-A-2-300744
No. 3, No. 3-39740, No. 3-67253, No. 3-67254, No. 3-672
The compounds described in each of the publications such as No. 55, No. 3-124449 and No. 3-296746 can be used.

Examples of the non-polymeric dye-donor substances include JP-A-59-159151, 59-71046 and 59-123837.
No. 60-93434, No. 62-118343, No. 63-40152 and No. 63-71845 can be used.

In the image forming method of the present invention, the diffusible dye formed or released during thermal development has a molecular weight of
It is preferably 800 or less from the viewpoint of dye transferability, and particularly 7
Those of 00 or less are preferable.

Next, a method for adding the polymer dye-donor substance and the correction dye-donor substance of the present invention to the photothermographic material will be described.

The polymer dye-providing substance and the correction dye-providing substance of the present invention may be added by wet pulverizing into fine particles by a ball mill, sand mill or the like, or by emulsifying and dispersing in a hydrophilic colloid solution. It is preferably emulsified and dispersed in a hydrophilic colloid solution containing an anionic surfactant.

At this time, known high-boiling point organic solvents (dioctyl phthalate, diisodecyl phthalate, tricresyl phosphate, trinonyl phosphate, N, N-).
It is preferable to emulsify and disperse with (eg, diethyllaurylamide).

Next, the photothermographic material used in the image forming method of the present invention will be described.

As the photosensitive silver halide used in the photothermographic material of the present invention, those known in the art can be used, for example, silver chloride, silver bromide, silver iodobromide and silver chlorobromide. Alternatively, silver chloroiodobromide can be used.

These silver halides have a uniform composition from the inside to the surface of the grain, a so-called core / shell type in which the composition is different between the inside and the surface, or a multi-layer structure in which the composition changes stepwise or continuously. It may be silver halide.

The shape of silver halide is cubic, spherical,
Those having a clear crystal habit such as octahedron, dodecahedron, and tetrahedron, and those not having a clear crystal habit can be used. Further, for example, as described in JP-A-58-111933, JP-A-58-111934 and Research Disclosure 22,534, there are two parallel crystal planes, and these crystal planes are different from each other. Tabular silver halide grains having an area larger than the surface and having a grain diameter to thickness ratio of about 5: 1 or more can also be used.

In addition, for example, US Pat.
3,220,613, 3,271,257, 3,317,322, 3,51
1,622, 3,531,291, 3,447,927, 3,761,266
No. 3, No. 3,703,584, No. 3,736,140, No. 3,761,276,
JP-A-50-8524, 50-38525, 52-15661, 55-
The internal latent image type silver halide emulsions whose grain surfaces are not fogged in advance, such as those described in 127549, can also be used.

Further, the photosensitive silver halide can be added with a metal ion species such as iridium, gold, rhodium, iron and lead in the form of an appropriate salt at the grain forming stage.

The light-sensitive silver halide emulsion has a grain size of about 0.1.
02 to 2 μm, preferably about 0.05 to 0.5 μm.

In the present invention, as a method for preparing a photosensitive silver halide, a photosensitive silver salt forming component is allowed to coexist with an organic silver salt described below, and a part of the organic silver salt is converted into a part of the photosensitive silver halide. Can also be formed.

The photosensitive silver halide emulsion is obtained by chemically sensitizing the surface of the silver halide grain with a known sensitizer (eg, active gelatin, inorganic sulfur, sodium thiosulfate, thiourea dioxide, sodium chloroaurate). You can The chemical sensitization can also be performed in the presence of a nitrogen-containing heterocyclic compound or a mercapto group-containing heterocyclic compound.

Further, the photosensitive silver halide can be spectrally sensitized to blue, green, red and infrared rays by a known spectral sensitizing dye. Typical sensitizing dyes are cyanine,
Examples thereof include merocyanine, trinuclear or tetranuclear cyanine, holopolar cyanine, styryl, hemicyanine and oxonol. The amount of these sensitizing dyes used is 1 μmol to 1 mol, preferably 10 μmol to 0.1, per mol of silver halide.
mol. The sensitizing dye may be added at any stage of the silver halide emulsion, and specifically, during formation of silver halide grains, removal of soluble salts, before initiation of chemical sensitization, during chemical sensitization, or chemical sensitization. It may be after the end.

These light-sensitive silver halide and light-sensitive silver salt-forming components are used in an amount of about 0.01 to 50 g, preferably 0.1 to 10 g per 1 m ² of the light-sensitive material.

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

Organic silver salts that can be used in the present invention include, for example, JP-A Nos. 53-4921, 49-52626 and 52-52.
141222, 53-36224, 53-37626, 53-36224
No. 53-37610, etc. and U.S. Pat.
Nos. 3,794,496, 4,105,451 and the like, long-chain aliphatic carboxylic acid silver salts and heterocyclic carboxylic acid silver salts (for example, silver behenate, α- (1-
(Phenyltetrazolethio) silver acetate, etc.) or Japanese Patent Publications No. 44-26582, No. 45-12700, No. 45-18416, and No. 45-228
No. 15, JP-A Nos. 52-137321, 58-118638 and 58-11863.
There is a silver salt of a compound having an imino group, which is described in US Pat. No. 9,123,274 and the like. Furthermore, JP-A-61
The acetylene silver described in -249044 can also be used.

Of these, silver salts of compounds having an imino group are preferable, and silver salts of benzotriazole and its derivatives (for example, silver benzotriazole and silver 5-methylbenzotriazole) are particularly preferable.

The above organic silver salts may be used alone or in combination of two or more kinds. These are prepared in an aqueous solution of hydrophilic colloid such as gelatin, and the soluble salts are removed before use as they are. Alternatively, the organic silver salt can be isolated and mechanically pulverized and dispersed into solid fine particles for use. The amount of organic silver salt used is 0.01 g per 1 m ² of light-sensitive material.
-20g, preferably 0.1-5g. A thermal solvent is preferably used in the photothermographic material of the invention for the purpose of accelerating the transfer of dyes and other purposes.

The thermal solvent is a compound having a function of liquefying during thermal development and promoting thermal development and thermal transfer of dye, and it is preferably in a solid state at room temperature.

Examples of the thermal solvent that can be used in the present invention include US Pat. Nos. 3,347,675, 3,667,959, and 3,347,675.
438,776, 3,666,477, Research Disclosure (No. 17,643, JP-A-51-19525, 53-24829,
53-60223, 58-118640, 58-198038, 59-2
29556, 59-68730, 59-84236, 60-191251
No. 60, No. 60-232547, No. 60-14241, No. 61-52643, No. 6
2-78554, 62-42153, 62-44737, 63-53548
No. 63-161446, JP-A Nos. 1-224751 and 2-863, and the like.

Specifically, urea derivatives (dimethylurea,
Dimethylurea, phenylurea, etc.), amide derivatives (eg acetamide, stearylamide, benzamide, p
-Toluamide, p-acetoxyethoxybenzamide,
P-butanoyloxyethoxybenzamide etc.), sulfonamide derivative (eg p-toluenesulfonamide etc.) and polyhydric alcohols (eg 1,6 hexanediol, pentaerythritol, polyethylene glycol etc.) are preferably used.

Among the above-mentioned thermal solvents, a water-insoluble solid thermal solvent is particularly preferably used, and among them, an amide-based thermal solvent or a urea-based thermal solvent is preferably used from the viewpoint of color developability.

The following can be mentioned as such specific examples.

The above thermal solvent can be added to any layer such as a photosensitive silver halide emulsion layer, an intermediate layer, a protective layer, an image receiving layer of an image receiving member, and the addition amount thereof is usually relative to the binder. It is 10% by weight to 500% by weight, more preferably 30% by weight to 300% by weight.

The binder that can be used in the photothermographic material of the present invention includes polyvinyl butyral, polyvinyl acetate, ethyl cellulose, polymethacrylate, polyvinyl alcohol, polyvinyl pyrrolidone, gelatin, gelatin derivatives such as phthalated gelatin, and cellulose derivatives. , Protein, starch, gum arabic, carrageenan, and other synthetic or natural polymer substances, and these can be used alone or in combination of two or more. In particular, it is preferable to use gelatin or a derivative thereof in combination with a hydrophilic polymer such as polyvinylpyrrolidone, polyethylene glycol or polyvinyl alcohol, and particularly preferably a mixed binder of gelatin and polyvinylpyrrolidone or polyethylene glycol and gelatin is used.

The amount of the binder used is usually 0.05 g to 20 g, and preferably 0.2 g to 10 g per 1 m ^{2 of the} support.

In addition to the above, various additives can be added to the photothermographic material of the present invention, if necessary.

Examples of development accelerators that can be used in the present invention include those disclosed in JP-A-59-177550 and JP-A-59-1116.
No. 36, No. 59-124333, No. 61-72233, No. 61-236548,
The compounds described in JP-A-1-152454 are useful, and the development accelerator releasing compounds described in JP-A-61-159642, JP-A-1-104645 and JP-A-3-67256, or JP-A-1 -1046
Metal ions having an electronegativity of 4 or more described in No. 45 can also be used.

Examples of the antifoggants which can be used in the present invention include higher fatty acids described in US Pat. No. 3,645,739, secondary mercury salts described in JP-B-47-11113, and JP-A-51. -47419, N-halides, US Pat. No. 3,700,457, and JP-A-51-50725.
JP-A-2-297548, mercapto compound-releasing compounds described in JP-A No. 2-282241, arylsulfonic acid described in JP-A-49-125016, lithium carboxylic acid salt described in JP-A-51-47419, British Patent No. 1,455,271 And oxidants described in JP-A-50-101019, sulfinic acids and thiosulphonic acids described in 53-19825, thiouracils described in 51-3223, and 5
1-26019 Sulfur, 51-42529, 51-81124, and 55-93149 disulfides and polysulfides, 51-57435 rosin or diterpenes, 51-104338 Polymeric acid having a carboxyl group or a sulfonic acid group described, U.S. Pat. No. 4,138,265 thiazolithion, JP-A-54-51821, JP-A-55-142331,
Triazoles described in U.S. Pat.
Thiosulfinic acid esters described in 5-140883, JP
59-46641, 59-57233, di- or tri-halides described in 59-57234, thiol compounds described in JP-A-59-111636, 60-198540 and 60-227255 described. Examples thereof include hydroquinone derivatives. Further preferred examples of the antifoggant include an antifoggant having a hydrophilic group described in JP-A-62-78554, a polymer anti-foggant described in JP-A-62-121452, and JP-A-62-123456. The antifoggants having the described ballast group may be mentioned. The colorless coupler described in JP-A 1-161239 is also preferably used.

Examples of the base precursor that can be used in the present invention include compounds that decarboxylate by heating to release a basic compound (guanidine trichloroacetic acid, etc.), amines that are decomposed by an intramolecular nucleophilic substitution reaction. And a base precursor that releases a base by the reaction of a compound that is difficult to dissolve in water (basic metal compound such as zinc hydroxide) and a compound (picolinic acid) that can form a complex with the metal ion that forms it Examples of such techniques include, for example, JP-A-56-130745, 59-157637, and 59-166943.
No. 59-180537, 59-174830, 59-195237,
62-108249, 62-174745, 62-187847, 63-
No. 97942, No. 63-96159, JP-A No. 1-68746 and the like.

The photothermographic material of the present invention may contain a reducing agent other than the above.

Examples of such reducing agents include ascorbic acid or its derivatives, hydroquinone and its derivatives, catechol and its derivatives, pyrogallol and its derivatives, 1-phenyl-3-pyrazolidone and its derivatives, and the like.

Particularly when a diffusible dye is formed or released from a dye-donor substance and it is necessary to combine with an oxidant of the reducing agent, a reducing agent represented by the following general formula (5) is used. Particularly preferred.

[0129]

[Chemical 13]

R ₃₁ and R ₃₂ each independently represent an alkyl group or an alkenyl group. R ₃₃ , R ₃₄ , R ₃₅ and R ₃₆
Each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkoxy group, a halogen atom, a carbamoyl group, an acylamino group, an aminosulfonyl group, a sulfamoyl group or a heterocyclic group.

A represents an --OH group or an --NH--W group.
W is -SO ₃ R ₃₇ group (R ₃₇ is a hydrogen atom, an alkali metal atom, -NH ₄₊ group, an alkyl group, an alkenyl group, a cycloalkyl group or an aryl group) or -CONHR
Group ₃₈ (R ₃₈ represents an alkyl group, an alkenyl group, an aryl group or a heterocyclic group).

Various known photographic additives other than those mentioned above can be used in the photothermographic material of the invention. Examples thereof include antihalation dyes, colloidal silver, optical brighteners,
A hardener, an antistatic agent, a surfactant, an inorganic or organic matting agent, an anti-fading agent, an ultraviolet absorber and a white background color tone adjusting agent may be contained. These are specifically RD
(Research Disclosure) Magazine No.17029, N
No. 29,963, JP-A Nos. 62-135825 and 64-13546.

Particularly, halogen-substituted heterocyclic compounds described in JP-A-63-118155, and JP-A-2-44356
It is preferred to include an adsorbent material that adsorbs contaminants such as the activated carbon described in US Pat.

These various additives can be appropriately added not only to the photosensitive layer but also to any constituent layer such as an intermediate layer, an undercoat layer, a protective layer or a backing layer.

The support used in the photothermographic material of the present invention is, for example, glass, polypropylene film,
On transparent or opaque synthetic plastic films such as cellulose acetate film, polyethylene terephthalate film, polyethylene naphthalate film, various coated papers such as art paper, cast coated paper, baryta paper, polyethylene resin coated paper, and various such supports. Examples thereof include a support coated and cured with an electron beam curable resin composition.

The photothermographic material of the present invention comprises at least one layer containing the polymer dye-donor of the present invention on a support. The polymer dye-donor-containing layer comprises two or more layers. It may be. In that case, the polymeric dye-donor materials contained in each layer may be the same or different. The layer to which the correction dye-donor substance preferably used in the present invention is added may be the same as or different from the layer containing the polymer dye-donor substance.

The photothermographic material of the present invention contains a photosensitive silver halide, but preferably the photosensitive silver halide is added to the layer containing the polymeric dye-donating substance of the present invention.
The photosensitivity of the photosensitive silver halide may be any of blue, green, red, infrared, etc., and may have two or more color sensitivities.

An image receiving material is used in the image forming method of the present invention. The image-receiving material is composed of a support and an image-receiving layer having a dye-receiving ability provided on the support,
The support itself can also serve as an image receiving layer having a dye receiving ability. The image-receiving layer is roughly classified into a case where the binder itself constituting the image-receiving layer has a dye-receiving ability and a case where a mordant capable of receiving the dye is contained in the binder.

When the binder has a dye-accepting ability, a substance preferably used has a glass transition temperature of about 40 ° C. or higher,
Those formed of a polymer having a temperature of about 250 ° C. or lower are preferable, and specifically, “Polymer Handbook Second
Edition "(Joy Brand Wrap, E.
H. Inmargat) John Willie and Sons Publishing {Polymer Handbook 2nd. Ed. (J. Bran
Drup, EH Immergut ed) John Wiley & Sons} synthetic polymers with a glass transition temperature of about 40 ° C or higher are useful. Generally, a polymer having a molecular weight of about 2,000 to 200,000 is useful. Is. These polymers may be used alone or in combination of two or more.
It may be a copolymerizable polymer having one or more repeating units.

Specific examples thereof include polyvinyl chloride, polyester, polycarbonate, polyvinylidene chloride, and polyether, and the polyvinyl chloride described in JP-A-59-223425 and the polycarbonate described in JP-A-60-19138 are particularly preferable. .

Further, in the image receiving member in which the image receiving layer contains a mordant in the binder, a polymer containing a tertiary amine or a quaternary ammonium salt is preferably used as the mordant. For example, US Pat. 64-1354
The compounds described in No. 6 are mentioned. As the binder used for holding these mordants, hydrophilic binders such as gelatin and polyvinyl alcohol are preferably used.

A dye-receiving layer obtained by dispersing a hydrophobic polymer latex having dye-receiving ability in a hydrophilic binder in a form similar to the image-receiving layer having the mordant in the binder can also be used in the present invention.

The image-receiving material of the present invention may have a single image-receiving layer provided on a support, or may have a plurality of constituent layers coated thereon, in which case all of them are dyes. It may be an image receiving layer, or only a part of the constituent layers may be an image receiving layer.

When the image receiving material has a support separately from the image receiving layer, the support of the image receiving material may be either a transparent support or a reflective support. Specifically, for example, polyethylene phthalate, polycarbonate, polystyrene, polyvinyl chloride, polypropylene, and a support obtained by adding a white pigment such as barium sulfate, calcium carbonate, or titanium dioxide to the support, art paper, cast coat. It is possible to use paper, baryta paper, laminated paper in which a thermoplastic resin (polyethylene or the like) containing a white pigment is coated on a paper support, cloth, glass, metal foil such as aluminum, and the like. In addition, a support obtained by coating and curing an electron beam curable resin composition containing a pigment on the support, a reflective support having type II diffuse reflection, and the like are also supports of the image receiving material of the present invention. , Can be used.

The photothermographic material of the present invention is described in RD (Research Disclosure) No. 15,108, JP-A-57-198458.
No. 57-207250, No. 61-80148, etc., a so-called monosheet type photothermographic material in which a photosensitive layer and an image receiving layer are previously laminated on the same support can also be used. .

Various known additives can be added to the image receiving material of the present invention. Examples of such additives include stain inhibitors, ultraviolet absorbers, optical brighteners, image stabilizers, development accelerators, antifoggants, pH adjusters (acid and acid precursors, base precursors, etc.), heat Examples thereof include solvents, organic fluorine compounds, oil drops, surfactants, hardeners, matting agents and various metal ions.

The photothermographic material of the present invention can be exposed by a known exposure means suitable for the color sensitivity of the photosensitive material.

As the exposure light source that can be used, a tungsten lamp, a halogen lamp, a xenon lamp,
A mercury lamp, a CRT light source, a FO-CRT light source, a light emitting diode, a laser light source (for example, a gas laser, a dye laser, a YAG laser, a semiconductor laser, etc.) can be used alone or in combination. Further, a light source in which a semiconductor laser and an SHG element (second harmonic generation element) are combined can also be used. In addition, the light can be exposed by the light emitted from the phosphor excited by an electron beam, X-ray, γ-ray, α-ray, or the like.

The photothermographic material of the present invention is preferably 70 to 200 ° C., more preferably 90 to 170 ° C., preferably 1 to 180 seconds, more preferably 2 to 120 after imagewise exposure or at the same time as exposure. It is heat-developed for a second to form a dye image. The transfer of the diffusible dye to the image-receiving material may be carried out simultaneously with the heat-development by bringing the image-receiving layer side of the image-receiving material into close contact with the photosensitive layer side of the photosensitive material during the heat-development. The dye may be transferred by bringing it into close contact with the material, and further, after supplying water, the photosensitive material and the image receiving material may be brought into close contact with each other. Further, the light-sensitive material is preheated in the range of 70 to 160 ° C. before exposure, or as described in JP-A-60-143338 and 61-162041, the light-sensitive material and the image-receiving material immediately before development. At least one of 80-120 ℃
It is also possible to preheat in the temperature range of.

When the heat-developable photosensitive material of the present invention is heat-developed, known heating means can be applied. For example, it is brought into contact with a heated heat block or surface heater, or a heating roller or a heating drum. With a high-temperature heating method, a method using a high-frequency heating method, a heating method with a far-infrared heating means, or a heating conductive material such as a carbon black layer on the back surface of the photosensitive material or the image receiving material. It is possible to apply a method in which Joule heat generated by providing a conductive substance and applying electricity is used.

The heating pattern at the time of heat development is not particularly limited, and it may be carried out at a constant temperature, at a high temperature in the early stage of development and at a low temperature in the latter half of the development, or vice versa, or at a temperature of 3 steps or more. Any method such as a method of changing the area or a method of continuously changing the temperature can be used.

[0152]

EXAMPLES Examples of the present invention will be shown below, but the embodiments of the present invention are not limited thereto.

Example 1 [Preparation of Photothermographic Material] A photothermographic material was prepared by coating the following layers on a photographic variator paper support having a thickness of 160 μm.
1-6 were created.

Here, the addition amount of each material is the photothermographic material 1
m indicates an amount per ^2, the amount of light sensitive silver halide emulsions and silver benzotriazole emulsion represents respectively in terms of silver, the amount of dye-providing material showed in terms of the total amount of diffusible dye .

Undercoat layer Polyphenylene ether 2.0 g Polystyrene 2.0 g Trapping agent 0.4 g First layer Benzotriazole silver 0.62 g Green photosensitive silver halide emulsion 0.33 g Dye-donor (Table 3) 2.0 mmol TCP (tricresyl phosphate) 0.3g DAP 0.03g DID 0.06g Polyvinylpyrrolidone (PVP; K = 30) 0.13g Gelatin 1.72g Phenylcarbamoyl gelatin 0.36g Potassium bromide 0.005g Hot solvent-A 1.65g ST-2 0.01g Anti-irradiation dye-1 0.03 g surfactant -1 0.09 g surfactant -2 0.011 g second layer gelatin 0.50g PVP 0.08g ZnSO ₄ 0.14g color developer precursor (R-1) 3.2 mmol of surfactants -2 0.04 g hardener ( H-1) 0.15 g The structural formulas of the additives used, the photosensitive silver halide emulsion, the silver benzotriazole, and the thermal solvent are shown below.

[0156]

[Chemical 14]

[0157]

[Chemical 15]

[0158]

[Chemical 16]

(Green-Sensitive Silver Halide Emulsion) Cubic AgBrI (AgI composition; 2 mol%) having an average grain size of 0.165 μm.

Chemical sensitization was performed to the optimum point with sodium thiosulfate in the presence of the above-mentioned sensitizing dye (GSD-1) and 1-phenyl-5-mercaptotetrazole.

After the chemical sensitization, 1 g of 4-hydroxy-6-methyl-1-3-1 was used as a stabilizer per mol of silver halide as a stabilizer.
3a-7-Tetrazaindene was added.

(Benzotriazole silver) Benzotriazole and silver nitrate aqueous solution were simultaneously mixed in a phenylcarbamoyl gelatin aqueous solution to prepare silver benzotriazole. After the pH was lowered and desalted, the pH of the solution was adjusted to 6.0. A needle crystal dispersion having a length of 0.3 to 1.5 μm and a width of 0.1 to 0.5 μm was obtained.

(Hot-solvent dispersion) 100 g of hot-solvent was added to 0.2% gelatin aqueous solution, and the particle size was adjusted to about 0.4 with a sand mill disperser.
A μm fine particle solid dispersion was obtained.

(Dye-donor substance dispersion liquid) Dye-donor substance 2.0
6000 ml of mol, DAP30g, DID60g, and TCP300g
Heat-dissolve it in ethyl acetate, and add it to a 3% aqueous gelatin solution.
It was added to 12000 ml (containing 60 g of surfactant-1), emulsified and dispersed by a high-speed homogenizer, and ethyl acetate was removed under reduced pressure to a total amount of 14000 ml.

Photothermographic Material Dye Donor 1 PC-42 PC-6 3 PC-9 4 PC-11 The resulting photothermographic material was stored for 2 days at 40 ° C. and 60% relative humidity to obtain the desired hardness. Hardened to the film thickness.

[Preparation of Image Receiving Material] An image receiving layer having the following composition was coated on the photographic baryter paper support used for preparing the photothermographic material 1 to prepare an image receiving material-1.

Polycarbonate 12 g Trap agent 1.2 g Hot solvent-B 4.2 g Image stabilizer-2 1.0 g UV absorber-1 1.0 g The image receiving layer was formed by coating the above composition on a support using dichloroethane as a solvent.

[Evaluation of Photothermographic Material] The photothermographic material prepared as described above was subjected to uniform exposure by changing the exposure amount, and then heat-developed at 150 ° C. for 60 seconds. Then, the dye image was transferred onto the image receiving layer by superposing it on the image receiving material 1 and heating at 130 ° C. for 30 seconds.

The obtained transferred image was measured for spectral reflection density with a 607 type color analyzer manufactured by Hitachi Ltd.
L *, a *, and b * were determined by the method specified in -Z-8729.

Next, the value of L * was plotted on the abscissa and a * and b * were plotted on the ordinate respectively, and a * and b * at which L * was 20, 30, and 40 were obtained. The results are shown in Table 3.

[0171]

[Table 3]

From the results shown in Table 3, it can be seen that each of the photothermographic materials-1 to 4 of the present invention can obtain good neutral stability against a change in transfer density. In particular, it can be seen that the photothermographic materials-1 to 3 using the polymer dye-providing substance consisting of three monomers show good neutral stability.

Comparative Example 1 Using the polymer dye-donating substances (monomer polymers) shown in Table 2, photothermographic materials-1 and -2
Comparative photothermographic materials-1R and 2R were prepared in the same manner as in.

The photothermographic material 1R contains CC-7, CC-8, and CC-9 instead of the polymer dye-donor, and the photothermographic material-2R contains CC-10, CC-8, and CC. -9 was added so that the molar amount of each of the monomers was equal to the ratio of PC-4 and PC-6.

Each of the polymeric dye-providing substances was dispersed at the same time when the emulsion was dispersed.

The resulting photothermographic materials-1R and 2R
Was evaluated in the same manner as in Example-1. The results are shown in Table 4.

[0177]

[Table 4]

From the results shown in Table 4, it can be seen that the neutral stability tends to be lower than that of the photothermographic material of the present invention when the polymer dye-donating substance is mixed.

Example 2 Photothermographic materials prepared in Example 1 and Comparative Example 1
1, 2, 1R and 2R were stored at 40 ° C. and 80% relative humidity for 5 days. Then, the same evaluation as in Example 1 was performed. The results are shown in Table 5.

[0180]

[Table 5]

From the results shown in Table 5, it can be seen that the photothermographic material of the present invention shows little reduction in neutral stability even when stored under high humidity conditions.

Example 3 A photothermographic material-10 was prepared by coating the following layers on the photographic baryrator paper support having a thickness of 160 μm used in Example 1.

(Undercoat layer) Polyphenylene ether 2.0 g Polystyrene 2.0 g Trap agent 0.4 g (First layer) Benzotriazole silver 0.52 g Green light-sensitive silver halide emulsion 0.329 g Dye-donor (PC-2) 1.3 mmol TCP ( Tricresyl phosphate) 0.3g DAP 0.03g polyvinylpyrrolidone (PVP; K = 30) 0.13g gelatin 1.72g phenylcarbamoyl gelatin 0.36g potassium bromide 0.005g hot solvent-A 1.65g ST-2 0.01g anti-irradiation dye- 1 0.03 g surfactant -1 0.09 g surfactant -2 0.011 g (second layer) gelatin 0.50g PVP 0.08g ZnSO ₄ 0.14g color developer precursor (R-1) 3.2 mmol of surfactants -2 0.04 g Hardener (H-1) 0.15 g On the other hand, in the photothermographic material-10, a dye-donor substance was added as P.
A photothermographic material-11 in which C-2 was changed to a mixture of CC-4, CC-5 and CC-6 was prepared in the same manner as the photothermographic material-10. Further, in the photothermographic material-10, the dye-donor substance is a non-polymer dye-donor substance (R
Y, RM, RC) modified photothermographic material-
Created 11. The amounts of the dye-donor substances added were all equimolar when converted to diffusible dyes.

[0184]

[Chemical 17]

The resulting heat-developable light-sensitive materials-10 to 11 were subjected to uniform exposure with different exposure amounts in the same manner as in Example 1 and heat-developed under the same conditions as in Example 1 to obtain the image-receiving material described in Example 1. Was used to perform dye transfer. The neutral stability was investigated in the same manner as in Example 1. The results are shown in Table 6.

[0186]

[Table 6]

From the results shown in Table 6, it can be seen that the photothermographic material using the polymer dye-donor of the present invention has a high neutral stability.

Example 4 The photothermographic materials-10 to 12 prepared in Example 3 were subjected to thermal development and dye transfer in the same manner as in Example 3 with the unexposed state.
The blue, green and red reflection densities of the obtained white background were measured.
On the other hand, a dye image receiving material having a transferred image is set at 60 ° C and a relative humidity of 65.
% For 7 days, and the white density was measured in the same manner. The results are shown in Table 7.

[0189]

[Table 7]

Example 5 A synthetic scale of the polymer dye-donor PC-4 used in the photothermographic material-1 prepared in Example 1 was used as Synthesis Example-1.
A photothermographic material-1X having the same constitution as the photothermographic material-1 prepared in Example-1 was prepared by using the polymer obtained by halving the above. Thermal development in the same manner as in Example-1,
As a result of dye transfer, the results shown in Table 8 were obtained.

On the other hand, in the photothermographic material-1X, the correction dye-donating substance (CC-8) which is a magenta coupler was used as a dye-donating substance in an amount of 0.8 mol% relative to PC-4 (the total dye-donating amount contained in PC-4). Table 8 also shows the results of preparing the photothermographic material-1Y in which the ratio of the material to the monomer) was added.

[0192]

[Table 8]

From this result, it is understood that stable neutrality can be achieved by using a small amount of the correction dye-donating substance even if the polymer changes.

[0194]

INDUSTRIAL APPLICABILITY According to the present invention, in the photothermographic material which forms or releases a diffusible dye image by heat development and transfers it to the image receiving layer to form a black and white dye image, the difference in the density of the transferred image Gives a black image in which the neutrality hardly deteriorates, and the white background after transfer is good,
Moreover, it was possible to provide a photothermographic material capable of forming a black and white image in which the increase in stain was suppressed even when stored under high temperature conditions.

Claims (4)

[Claims] 1. A photosensitive silver halide emulsion on a support,
In a photothermographic material containing a binder and a polymer dye-donor substance that forms or releases a diffusible dye upon thermal development, the polymer dye-donor substance forms or releases a diffusible dye having substantially different color tones from each other. A photothermographic material, which is a polymer dye-providing substance having a repeating unit derived from at least two kinds of dye-donor substance monomers. 2. The photothermographic material according to claim 1, wherein the polymer dye donating substance is a polymer dye donating substance represented by the following general formula (1). [Chemical 1] [In the formula, R ₁ and R ₂ represent a hydrogen atom or an alkyl group, J ₁ and J ₂ represent a divalent linking group, and D ₁ and D ₂
Represents a dye moiety which becomes diffusible by separating from J ₁ and J ₂ during thermal development, respectively, or binds with an oxidant of a reducing agent at an active point and separates from J ₁ and J ₂ to form a diffusible dye. Represents a coupler residue to be formed. However, the maximum absorption wavelength of the diffusible dye derived from D ₁ is in the range of 420 to 550 nm, and the maximum absorption wavelength of the diffusible dye derived from D ₂ is 5
It is in the range of 70 to 700 nm. B represents a repeating unit that does not form or release a diffusible dye upon heat development. x, y and z each represent the ratio (molar ratio) of repeating units constituting the polymer, and each is 0.10 to 0.90 (provided that x + y +
The range is z = 1). ] 3. The photothermographic material according to claim 1, wherein the polymer dye donating substance is a polymer dye donating substance represented by the following general formula (2). [Chemical 2] [In the formula, R ′ ₁ , R ′ ₂ and R ′ ₃ represent a hydrogen atom or an alkyl group, J ′ ₁ , J ′ ₂ and J ′ ₃ represent a divalent linking group, and D ′ ₁ , D ′ ₂ and D ′ ₃ are D ₁ in the general formula (1)
Alternatively, it has the same meaning as D ₂ . However, D' ₁ , D' ₂ and D' ₃
The maximum absorption wavelengths of diffusible dyes derived from
420-480 nm, 520-580 nm and 620-720 nm. B '
Is synonymous with B in the general formula (1). p, q, r and s each represent the ratio (molar ratio) of the repeating units constituting the polymer, and each is 0.05 to 0.90 (where p + q + r + s =
It is the range of 1). ] 4. The photothermographic material according to claim 1, 2 or 3 further comprises, in addition to the polymer dye-donating substance, a dye-donor substance which forms or releases a single diffusible dye upon thermal development. The photothermographic material according to claim 1, 2, or 3.