JP2003066561A - Photothermographic imaging material having improved light fogging resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photothermographic imaging material having high sensitivity, low fogging and excellent photographic performances, to provide a photothermographic imaging material also having improved light fogging resistance particularly after thermal development and to provide a photothermographic imaging material having a high film strength and less liable to scuffing. SOLUTION: The photothermographic imaging material having at least a photosensitive layer containing photosensitive silver halide grains, an organic silver salt, a reducer for the organic silver salt and a binder on a support, is characterized in that a polymer obtained by copolymerizing a monomer unit having an anti-light-fogging group represented by formula (1) and a vinyl monomer unit having no anti-light-fogging group is contained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photothermographic image-forming material, and more particularly to a photothermographic image having high sensitivity, low fog, high film strength and scratch resistance, and particularly improved photofog resistance after heat development. The present invention relates to an image forming material (hereinafter, also referred to as photothermographic material).

[0002]

2. Description of the Related Art In recent years, a photothermographic material that does not produce waste liquid associated with a wet process has been strongly desired in the fields of medical treatment and printing from the viewpoint of environmental protection and workability. Technologies relating to photothermographic materials capable of forming images and used in photographic technology have been commercialized and rapidly spread. Since these photothermographic materials are usually developed at a temperature of 80 ° C. or higher, they are called photothermographic image forming materials in distinction from conventional photosensitive materials which are liquid-developed in the range of 25 to 45 ° C.

This type of photothermographic image-forming material has hitherto been irradiated to a photosensitive layer containing a highly sensitive silver halide grain spectrally sensitized with a dye, an organic silver salt and a reducing agent, and the photosensitive layer. An irradiation prevention layer (AI layer) for preventing light from passing through without being absorbed and being irregularly reflected at the interface of the support, the intermediate layer, the adhesive layer, or the backing layer (BC layer) provided on the opposite side of the support. Further, a protective layer for preventing scratches during handling is provided on the photosensitive layer and the BC layer.

Generally, a photothermographic image forming material is easy to process because it produces an image only by heat development after exposure, but since there is no fixing step, it is important to suppress light fog after development. In order to suppress the light fog after development, it is known to suppress it with a light fog suppressor.

The use of a polyhalomethane compound as a photofogging inhibitor for controlling photofogging is disclosed in JP-A-63-40611, 2001-1711063 and the like. However, a polyhalomethane compound is used as a photofogging inhibitor in a photothermographic material because it can release a halogen radical by photoexcitation to reduce fog, but it deteriorates sensitivity when the halogen radical releasing ability is high. Since the amount used is limited, the polyhalomethane compound has a problem that the effect of suppressing light fog is not sufficient and high sensitivity is difficult to obtain.

Further, as a light stabilizer, a hindered amine light stabilizing compound (usually abbreviated as HALS)
Has been developed to prevent photo-deterioration of plastics. However, if these are used as they are for the suppression of light fog, the fog may be increased and the sensitivity may be lowered, probably because the so-called basic action of the amine compound is exerted. In addition, there are problems that the film strength is lowered to easily cause scratches, and volatilizes during heat development to generate an odor.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a photothermographic image-forming material having high sensitivity and low fog and excellent photographic performance. Moreover, it is an object of the present invention to provide a photothermographic image-forming material having improved light fog resistance especially after thermal development. Another object of the present invention is to provide a photothermographic image forming material having high film strength and being less likely to be scratched.

[0008]

The above object of the present invention can be achieved by the following constitutions.

1. A photothermographic image-forming material having at least a photosensitive layer containing a photosensitive silver halide grain, an organic silver salt, a reducing agent for the organic silver salt, and a binder on a support is represented by the general formula (1). A photothermographic image-forming material comprising a polymer obtained by copolymerizing a monomer unit having a photo-fogging suppressing group and a vinyl monomer unit having no photo-fogging suppressing group.

2. The number average molecular weight of the polymer is 1,000 to 5
0,000 and glass transition point (Tg) 5 to 100 ° C
2. The photothermographic image forming material described in 1 above.

3. 3. The photothermographic image-forming material as described in 1 or 2 above, wherein at least one of the binders is a polymer represented by the general formula (2).

4. 0.1-20% by mass of the polymer represented by the general formula (2) is obtained by acetalizing at least one polymer represented by the general formula (2) between the molecules.
4. The photothermographic image-forming material as described in any one of 1 to 3 above, which is contained.

5. The binder of the photosensitive layer or a layer adjacent to the photosensitive layer contains a latex using at least one selected from styrene, butadiene and acrylate as a monomer unit.
5. The photothermographic image-forming material according to any one of items 4 to 4.

6. 6. At least one crosslinking agent selected from an isocyanate compound, a vinylsulfonyl compound, an epoxy compound and an alkoxysilane compound is added to the binder described above, Photothermographic image forming material.

7. 7. The photothermographic image-forming material as described in 6 above, wherein the alkoxysilane compound is an alkoxysilane compound represented by the general formula (3).

The present invention will be described in detail below. (Polymer of the Present Invention) A polymer obtained by copolymerizing a monomer unit having a photofogging suppressing group represented by the general formula (1) of the present invention and a vinyl monomer unit having no photofogging suppressing group (hereinafter, simply referred to as (Also referred to as a polymer of the invention).

First, the monomer having a photofogging suppressing group represented by the general formula (1) used in the polymer of the present invention will be described.

In the general formula (1), R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
Examples of the alkyl group of to 4 include a methyl group, an ethyl group, a propyl group, an iso-propyl group, a butyl group, and a te group.
Examples include rt-butyl group. These groups may be substituted with a halogen atom (eg, chlorine, bromine, fluorine atom, etc.), and an aromatic ring group (eg, a group derived from a benzene ring, a naphthalene ring, etc.) and a heterocycle (eg, , A group derived from a pyridine ring, a furan ring, a thiophene ring, a pyrimidine ring, or the like).

L ₁ represents a divalent linking group, and examples thereof include an alkylene group, an alkenylene group, and an alkynylene group each having 1 to 12 carbon atoms (for example, a methylene group, an ethylene group,
Propylene group, butylene group, pentylene group, dodecylene group, propenylene group, butyrenylene group, pentenylene group, dodecylenylene group, ethynylene group, propynylene group and the like). These groups may be substituted with a halogen atom (eg, chlorine, bromine, fluorine atom, etc.) and the like.

V ₁ represents a polymerizable vinyl group, and for example,
Acrylic acid, methacrylic acid, vinyl acetate, itaconic acid,
Examples thereof include a polymerizable vinyl group derived from a monomer having a skeleton such as maleic acid and styrene.

The preferred specific examples of the monomer having a photofogging suppressing group represented by the general formula (1) are shown below, but the invention is not limited thereto.

[0022]

[Chemical 4]

Next, the vinyl monomer having no photofogging suppressing group used in the polymer of the present invention will be described.

As the vinyl monomer having no photofogging suppressing group used in the polymer of the present invention, many commercially available vinyl monomers can be used. For example, styrene (St), butadiene (Bu), methyl acrylate (MA), methyl methacrylate (MMA), isononyl acrylate (INA), cyclohexyl methacrylate (CA), hydroxyethyl acrylate (HE).
A), hydroxyethyl methacrylate (HEMA),
Acrylic acid (AA), methacrylic acid (MAA) itaconic acid (IA), acrylamide (AAm), styrene sulfonic acid (St-S), acrylamido-2-methylpropane sulfonic acid amide (AMPS), isoprene sulfonic acid (IP- S), 2-propenyl-4-nonylphenoxyethylene oxide (n = 10) sulfonic acid ester (PF-S) and the like.

The polymer of the present invention is obtained by copolymerizing the above-mentioned monomer having a photo-fogging suppressing group represented by the general formula (1) with the above-mentioned vinyl monomer having no photo-fogging suppressing group. . As the monomer constituting the copolymer, two or more kinds of monomers having a photo-fogging suppressing group may be used, or two monomers having no photo-fogging suppressing group may be used.
You may use it in combination of 2 or more types. The method of copolymerization is
A plurality of monomers may be added to water, an alcohol solvent, a ketone solvent, a non-polar hydrocarbon solvent or the like in a fixed amount within a fixed time, or may be added in a divided manner, or may be divided into two portions and a double jet method may be used. You may add.

As the polymerization initiator, a general radical polymerization initiator is preferably used, and examples thereof include benzoyl peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, and azobisisobutyronitrile. Can be used. The reaction temperature is usually in the temperature range of 30 to 140 ° C, preferably 60 to 100 ° C.
And the reaction time is usually 1 to 15 hours, preferably 3 to 5 hours.

Preferred specific examples of the polymer of the present invention are shown below, but the present invention is not limited by these.

The ratio of monomers constituting the polymer of the present invention, the number average molecular weight, and the glass transition point (Tg) of the produced polymer are shown below. Among the monomers of Components 1 to 5, Component 3 represents a monomer having a photo-fogging suppressing group of the present invention, and the other components represent a vinyl monomer having no photo-fogging suppressing group.

[0029]

[Chemical 5]

In the present invention, the number average molecular weight of the polymer of the present invention is preferably 1,000 to 500,000, and 1 to 5
It is more preferable that it is 10,000. If it is less than 1,000, the film may be weak and may be easily scratched, and if it exceeds 500,000, the viscosity of the coating solution may be high and uniform coating may be difficult.

Further, the glass transition point (T
g) is preferably from 5 to 100 ° C, preferably from 15 to 60
More preferably, the temperature is ° C. If it is lower than 5 ° C, coagulation may easily occur in the coating solution, and if it exceeds 100 ° C, cracking may easily occur in the film.

The polymer of the present invention can be added to the coating solution by a known addition method. That is, it can be added by dissolving it in alcohols such as methanol and ethanol, ketones such as methyl ethyl ketone and acetone, polar solvents such as dimethyl sulfoxide and dimethylformamide, and the like. Further, it can be added by dispersing it in water or an organic solvent into fine particles of 1 μm or less by sand mill dispersion, jet mill dispersion, ultrasonic dispersion or homogenizer dispersion. Although many techniques for fine particle dispersion have been disclosed, they can be dispersed according to these techniques.

The polymer of the present invention is preferably added to a layer in which an additive such as silver halide, an organic silver salt and a reducing agent is present, but may be added to a layer adjacent to a layer containing these additives. Alternatively, it can be added via the intermediate layer.

When the polymer of the present invention is added, it may be added as fine particles dispersed in water or in an organic solvent without being dissolved in water or a solvent. To disperse the fine particles, the polymer of the present invention is subjected to a sand mill dispersion method using glass beads or zirconia fine particle media, a method in which a solution is jetted at high speed from a thin tube to collide with a hard plate-like object to be crushed, and a thin tube from two directions It is possible to use a method of causing the liquid of FIG. Fine particles are dispersed in an aqueous solution with an average particle size of 1 nm or more 1
The size is preferably 0 μm or less, and the particle distribution is preferably narrow. In order to disperse in an aqueous solution, it is preferable that bubbles are less likely to be generated by stirring.

The polymer of the present invention is preferably added to the photosensitive layer or a layer adjacent to the photosensitive layer, but it may be added to the intermediate layer or the undercoat layer. The amount of the polymer of the present invention added is preferably 1 × 10 ⁻⁸ to 1 × 10 ⁻¹ mol, and particularly preferably 1 × 10 ⁻⁵ to 1 × 10 ⁻² mol, per mol of silver. When added to a layer containing no silver other than the photosensitive layer, the addition amount can be determined by converting it into a unit area. If the addition amount is large, the sensitivity, the contrast and the maximum density are lowered, and if the addition amount is insufficient, it becomes difficult to obtain the effect of the present invention.

(Coating Method and Binder) In the present invention, when coating each layer coating solution containing a binder, solvent-based coating using an organic solvent that dissolves the binder, and latex or binder as a binder are used. There are two methods: aqueous coating using an aqueous solution.

Solvent-based coating refers to the case of coating a coating solution in which the ratio of the organic solvent is 40% or more and 100% or less, particularly 70% or more of the organic solvent. As the organic solvent, there are cases where a non-polar solvent system such as hexane, toluene and xylene and a polar solvent system such as acetone, methyl ethyl ketone, methyl isobutyl ketone, ethanol and isopropyl alcohol are used. It is frequently used because it can dissolve a large amount of additives.

Water-based coating means coating using a coating liquid in which the ratio of the organic solvent to the water content of the coating liquid composition is 0% or more and 40% or less in the preparation of the coating liquid. It is preferably 20% or less, more preferably 10% or less, and most preferably 5% or less.

When solvent-based coating is carried out, the binder is
Cellulose derivative, polyvinyl alcohol derivative, vinyl acetate derivative, acrylate polymer derivative, polyimide derivative, polyamide derivative, phenol resin derivative,
Examples thereof include urethane resin derivatives and polyester derivatives, and among them, polyvinyl alcohol derivatives and vinyl acetate derivatives are preferable. Examples of the binder preferably used in the present invention include the polymers represented by the general formula (2).

In the general formula (2), R ¹ and R ²
Each represents an alkyl group, and as the alkyl group,
An alkyl group having 1 to 12 carbon atoms is preferable, and examples thereof include a methyl group, an ethyl group, a butyl group, a hexyl group, a cyclohexyl group, an octyl group, and a dodecyl group.

D1, d2 and d3 represent monomer composition mass ratios (mass%), d1 represents 20 to 96 mass%, d2 represents 1 to 40 mass%, d3 represents 0.1 to 40 mass%, and d1 + d2 + d3 represents 100.

The polymer represented by the general formula (2) preferably has a molecular weight of 800 to 800,000. More preferably, it is 1 to 400,000. If the molecular weight is less than 800, it may be difficult to obtain film strength. Also, the molecular weight is 80
If it exceeds 50,000, the solubility may be deteriorated or the viscosity may be too large.

The polymer represented by the general formula (2) can also be intermolecular acetalized with each other.

The intermolecular acetalized polyvinyl alcohol derivative is obtained by reacting polyvinyl alcohol or aldehydes at a high concentration when adding aldehydes to polyvinyl alcohol for acetalization, and increasing the amount of acetalization catalyst added. , An acetalization catalyst may be additionally added in the latter stage of the reaction, the reaction temperature may be increased, stirring may be strengthened, and the like. Stirring intensity is Reynolds number of 1,000 to 10,000
It is preferably in the range of 0. The ratio of intermolecular acetalization is preferably in the range of 0.1 to 60% of the total polymer molecules, more preferably 1 to 30%, particularly preferably 3 to.
20%. This range is preferable because it is easy to control the viscosity of the coating liquid, the strength of the formed film is not weak, and there is elasticity.

The ratio of intermolecular acetal can be determined by liquid chromatography (GPC), viscosity measuring method and the like. For the production and analysis of the intermolecular acetal, JP-A-6-25213 can be referred to.

Examples of the polymer represented by the general formula (2) with intermolecular acetal include, for example, the following general formula (4)
The polymer represented by

[0047]

[Chemical 6]

[0048] In the formula, R ^1, R ^2, R ³ have the same meanings as R ^1, R ² in the general formula (2). d1, d2, d3 and d
4 represents the composition mass ratio (d4 represents the composition mass ratio of the intermolecular acetal portion), d4 represents 1 to 40 mass%, and d
1 + d2 + d3 + d4 is 100.

In the present invention, the polymer represented by the general formula (2) is obtained by acetalizing at least one intermolecular molecule of the polymer represented by the general formula (2) (for example, the above general formula). It is preferable to contain 0.1 to 20 mass% of the polymer represented by the formula (4). More preferably, it is 1 to 10 mass%. If it is less than 0.1% by mass, the film may be weak and may be easily damaged. On the other hand, if it exceeds 20% by mass, the viscosity of the coating solution becomes high and it may be difficult to apply it uniformly.

When water-based coating is carried out, a water-soluble polymer or a water-dispersible hydrophobic polymer (hereinafter also referred to as latex) can be mentioned as a preferable polymer used as the binder of the present invention. For example, polyvinylidene chloride, vinylidene chloride-acrylic acid copolymer, vinylidene chloride-itaconic acid copolymer, sodium polyacrylate, polyethylene oxide, acrylic acid amide-acrylic acid ester copolymer, styrene-maleic anhydride copolymerization Examples thereof include a polymer, an acrylonitrile-butadiene copolymer, a vinyl chloride-acetic acid moiety nyl copolymer, and a styrene-butadiene-acrylic acid copolymer. The latex described above constitutes an aqueous coating liquid, and forms a uniform polymer film at the stage of forming a coating film by drying after coating. Therefore, when the above latex is used, an organic silver salt, a silver halide, a reducing agent and the like are mixed as an aqueous dispersion with the above latex to form a uniform dispersion, which is then coated to form a photothermographic layer. To do. Upon drying, the latex coalesces particles to form a uniform film.

In the above latex, those having a glass transition point of -20 ° C to 80 ° C are preferable, and -5 ° C to 60 ° C.
C is more preferred. This is because if the glass transition point is high, the temperature for heat development is high, and if the glass transition point is low, fog is likely to occur, resulting in a decrease in sensitivity and a soft tone. The water-dispersible hydrophobic polymer is preferably dispersed in the form of fine particles having an average particle size of 1 nm to several μm.

Although the above-mentioned latex is widely used as a binder for water-based coating, a latex which improves water resistance as the binder is preferable. The amount of the latex used for obtaining water resistance as the binder is determined in consideration of coatability, but the larger amount is preferable from the viewpoint of moisture resistance, and 50% or more and 100% or less based on the total weight of the binder. It is preferably 80% or more and 100% or less.

In the present invention, among latexes (water-dispersible hydrophobic polymers) preferably used as a binder for aqueous coating, vinylidene chloride latex, styrene-butadiene-acrylic latex and the like, styrene-butadiene. -Specific examples of the acrylic latex are shown below.

[0054]

[Chemical 7]

In the above, St is styrene, Bu is butadiene, MA is methyl acrylate, INA isononyl acrylate, CA is cyclohexyl methacrylate, HEA is hydroxyethyl acrylate, HEMA is hydroxyethyl methacrylate, AA is acrylic acid, and methacrylic acid is methacrylic acid. Acid is MAA Itaconic acid is IA, Acrylamide is AAm, Styrenesulfonic acid is St-S, Acrylamide-2-methylpropanesulfonic acid amide is AMPS, Isoprenesulfonic acid is IP-S, 2-Propenyl-4-nonylphenoxyethylene oxide. (N
= 10) Sulfonic acid ester is abbreviated as PF-S.

In the present invention, the amount of the polymer binder used is 4 (based on the solid content in the case of latex) based on the amount of silver.
The amount is preferably 1 to 10 times, and when the amount of silver is 2.0 g / m ² , the amount of polymer is 0.5 to
It is preferably 20 g / m ² . Further, more preferably 1 to 7 times the amount of half the amount per silver amount per silver is 2.0 g / m ² if 1.0~14g / m ^2.
If the amount of silver adhered is one-fourth or less, the silver color tone may be significantly deteriorated and the product may not be usable. Further, if the amount of silver is 10 times or more, it may become soft and unusable.

(Crosslinking Agent Used in Combination with Binder) By forming a film of the binder alone, it is possible to maintain the adhesion to the lower layer and the upper layer and to obtain a film strength that is not easily scratched. When used together, the film adhesion can be further enhanced. However, if the crosslinking reaction is slow, the photographic performance is not stable and the storage stability is deteriorated. The rapid-acting and preferable crosslinking agent used in the present invention is a polyfunctional crosslinking agent having at least two selected from an isocyanate group, an epoxy group and a vinylsulfonyl group, or an alkoxysilane compound represented by the above general formula (3). Can be mentioned.

The alkoxysilane compound represented by the general formula (3) will be described. In the general formula (3),
R ³ represents an alkyl group, R ⁴ represents an aromatic group or a heterocyclic group, and L ₂ represents a divalent linking group. m and n are 1
Is an integer of 3 and m + n = 4.

Examples of the alkyl group represented by R ³ include a methyl group, an ethyl group, a propyl group, an iso-propyl group, a butyl group, a tert-butyl group and an octyl group.

Examples of the aromatic group represented by R ⁴ include a phenyl group and a naphthyl group.

Examples of the heterocyclic group represented by R ⁴ include a pyridyl group, a piperidyl group, a furyl group, a thiophenyl group, an imidazolyl group, an oxazolyl group, a thiazolyl group, a thiadiazolyl group and an oxadiazolyl group.

The divalent linking group represented by L ₂ is, for example, an alkylene group (eg, methylene group, ethylene group,
Butylene group, hexylene group, etc.), oxyalkylene group (for example, ethyleneoxyethylene group, tri (oxyethylene) group, octa (oxyethylene) group, etc.) and the like can be mentioned.

Specific examples of the crosslinking agent preferably used in the present invention are shown below. (H1) Hexamethylene diisocyanate (H2) Hexamethylene diisocyanate trimer (H3) Tolylene diisocyanate (H4) Phenylene diisocyanate (H5) Xylylene diisocyanate

[0064]

[Chemical 8]

[0065]

[Chemical 9]

The above-mentioned cross-linking agent may be dissolved in water, alcohols, ketones, non-polar organic solvents or the like and added, or may be added as a solid in the coating solution. The addition amount is
The equivalent amount to the crosslinkable group of the binder is preferable, but the amount may be increased up to 10 times, or may be decreased up to 1/10 or less.
If it is less than the above range, the crosslinking reaction may not proceed. On the other hand, if the amount exceeds the above range, the unreacted crosslinking agent may deteriorate the photographic property.

The other components used in the photothermographic image-forming material of the present invention will be described below.

Examples of the organic acid of the metal salt of the organic silver salt used in the present invention include fatty acids such as stearic acid, behenic acid and palmitic acid.

The photosensitive silver halide used in the photothermographic image-forming material of the present invention can be prepared by a method known in the photographic art, such as a single jet method or a double jet method, for example, an ammonia method emulsion, a neutral method or an acidic method. It can be prepared by any method such as a method. After preliminarily prepared in this manner, it can be mixed with other components of the present invention and introduced into the composition used in the present invention. In this case, in order to sufficiently bring the photosensitive silver halide into contact with the organic silver salt, for example, US Pat. Nos. 3,706,564 and 3,706 are used as protective polymers when preparing the photosensitive silver halide. , 5
No. 65, No. 3,713, 833, No. 3,748,
143, means for using polymers other than gelatin such as polyvinyl acetals described in British Patent No. 1,362,970, and photosensitive halogenation as described in British Patent No. 1,354,186. Means for enzymatically degrading gelatin in silver emulsions or US Pat. No. 4,076,5
By preparing the photosensitive silver halide grains in the presence of a surfactant as described in No. 39, it is possible to apply various means such as a means for omitting the use of a protective polymer.

The silver halide functions as a highly photosensitive material, and it is preferable that the grain size is small in order to suppress white turbidity after image formation and to obtain a good image quality. The average particle size is usually 0.1 μm or less,
Preferably 0.01-0.1 μm, 0.02-0.08
μm is more preferable. The shape of silver halide is not particularly limited, and may be cubic, octahedral, so-called normal crystal, non-normal crystal spherical, rod-shaped, tabular, or the like. The silver halide composition is also not particularly limited, and silver chloride, silver chlorobromide,
It may be any of silver chloroiodobromide, silver bromide, silver iodobromide and silver iodide.

The amount of silver halide used is usually 50% or less, preferably 0.1 to 25%, more preferably 0.1 to 15%, based on the total amount of silver halide and the organic silver salt described below.

The photosensitive silver halide used in the photothermographic imaging element of the present invention is also described in British Patent 1,447,
As described in No. 454, when an organic silver salt is prepared, a halogen component such as a halide ion is allowed to coexist with an organic silver salt-forming component, and silver ions are injected to produce an organic silver salt at approximately the same time. It is possible to produce a functional silver halide.

As still another method, a silver halide-forming component is allowed to act on a previously prepared solution or dispersion of an organic silver salt or a sheet material containing the organic silver salt, and a part of the organic silver salt is exposed to light. It can also be converted into a polar silver halide.
The silver halide thus formed is in effective contact with the organic silver salt and exhibits a preferable effect. The silver halide-forming component is a compound capable of reacting with an organic silver salt to produce a photosensitive silver halide. What kind of compound corresponds to this compound and is effective is determined by the following simple test. be able to. That is, the presence or absence of a peak peculiar to silver halide is examined by an X-ray diffraction method after mixing an organic silver salt with a compound to be tested and heating if necessary. The silver halide-forming components which have been confirmed to be effective by such a test include inorganic halides, onium halides, halogenated hydrocarbons, N-halogen compounds and other halogen-containing compounds. Are US Pat. Nos. 4,009,039 and 3,45.
No. 7,075, No. 4,003,749, British Patent No. 1,498,956, and JP-A Nos. 53-27027 and 53-25420 are described in detail below. .

(1) Inorganic halide: For example, a halide represented by MX _n (wherein M represents H, NH ₄ and a metal atom, n is 1 when M is H and NH ₄ , M
When is a metal atom, it represents its valence. Examples of the metal atom include lithium, sodium, potassium, cesium, magnesium, calcium, strontium, barium, zinc, cadmium, mercury, tin, antimony, chromium, manganese, iron, cobalt, nickel, rhodium and cerium), Further, halogen molecules such as bromine water are also effective.

These silver halide-forming components are used stoichiometrically in small amounts with respect to the organic silver salt. The amount used is usually 0.001 mol to 0.7 mol, preferably 0.03 mol to 0.5 mol, per mol of the organic silver salt. Two or more kinds of silver halide-forming components may be used in combination within the above-mentioned use amount range. Although various conditions such as reaction temperature, reaction time and reaction pressure in the step of converting a part of the organic silver salt into silver halide using the above-described silver halide-forming component can be appropriately set according to the purpose of preparation. , Usually the reaction temperature is -2
The reaction time is preferably 0 ° C. to 70 ° C., the reaction time is 0.1 seconds to 72 hours, and the reaction pressure is preferably set to atmospheric pressure. This reaction is also preferably carried out in the presence of the polymers used as binders as described above. The amount of the polymer used in this case is usually 0.01 per 1 part by mass of the organic silver salt.
To 100 parts by mass, preferably 0.1 to 10 parts by mass.

The photosensitive silver halide prepared by the above-mentioned various methods is, for example, a sulfur-containing compound, a gold compound,
Platinum compound, palladium compound, silver compound, tin compound,
It can be chemically sensitized with a chromium compound or a combination thereof. The method and procedure of this chemical sensitization are described in, for example, U.S. Pat. No. 4,036,650, British Patent No. 1,518,850, and JP-A-51-22430.
Nos. 51-78319 and 51-81124. Further, when a part of the organic silver salt is converted into a photosensitive silver halide by the silver halide-forming component, as described in U.S. Pat. No. 3,980,482, a low sensitization is required to achieve sensitization. An amide compound having a molecular weight may coexist.

In addition, these photosensitive silver halides are added to groups 11 to 6 of the Periodic Table of the Elements in order to adjust illuminance and gradation.
Group metals such as Rh, Ru, Re, Ir, O
An ion such as s or Fe, or a complex or complex ion thereof can be contained. These metal ions may be introduced into the silver halide as a metal salt as they are, but can be introduced into the silver halide in the form of a metal complex or a complex ion.

The content of these metal ions, metal complexes and complex ions is generally 1 × 10 ^-9 to 1 × 10 ^-2 mol, preferably 1 mol per mol of silver halide. It is x10 ^-8 to 1 x 10 ^-4 mol. An excessive amount of addition causes a decrease in sensitivity, a soft tone, and a decrease in maximum density, which is not preferable. A compound providing an ion or a complex ion of these metals is preferably added at the time of silver halide grain formation and incorporated into the silver halide grain. Preparation of the silver halide grain, that is, nucleation, growth and physical ripening. It may be added at any stage before and after chemical sensitization, but it is particularly preferable to add at the stage of nucleation, growth and physical ripening, more preferably at the stage of nucleation and growth, and nucleation It is particularly preferable to add at the stage of. At the time of addition, it may be divided and added several times,
It can be incorporated in the silver halide grains uniformly, and it can be incorporated in JP-A-63-29603 and JP-A-2-30623.
No. 6, No. 3-167545, No. 4-76534, No. 6-110146, No. 5-273683, etc., it is also possible to allow the particles to have a distribution.

These metal compounds can be added after being dissolved in water or a suitable organic solvent (eg alcohols, ethers, glycols, ketones, esters, amides). A method of adding an aqueous solution of the powder of (1) or an aqueous solution of a metal compound and NaCl, KCl together to a water-soluble silver salt solution or a water-soluble halide solution during grain formation, or a silver salt solution and a halide solution. When mixed simultaneously, a metal compound is added as a third aqueous solution, a method of preparing silver halide grains by a three-liquid simultaneous mixing method, and a method in which a necessary amount of an aqueous solution of a metal compound is charged into a reaction vessel during grain formation Alternatively, there is a method of adding and dissolving another silver halide grain which is previously doped with a metal ion or a metal complex ion at the time of preparing the silver halide. In particular, a method of adding an aqueous solution of a powder of a metal compound or an aqueous solution in which a metal compound and NaCl or KCl are dissolved together to a water-soluble halide solution is preferable. When added to the surface of silver halide grains, a necessary amount of an aqueous solution of a metal compound may be added to a reaction vessel immediately after grain formation, during or during physical ripening, or at the time of chemical ripening.

The photothermographic image-forming material of the present invention preferably contains a matting agent on the photosensitive layer side, and a matting agent is provided on the surface of the photothermographic material in order to prevent scratching of the image after heat development. It is preferable that the matting agent is contained in an amount of 0.5 to 30% by mass relative to the total binder on the photosensitive layer side.

When a non-photosensitive layer is provided on the side opposite to the photosensitive layer with a support sandwiched between them, it is preferable to include a matting agent in at least one layer on the non-photosensitive layer side, so that the photothermographic material can have excellent slipperiness and fingerprints. It is preferable to dispose a matting agent on the surface of the photothermographic material in order to prevent adhesion, and the matting agent is used in a mass ratio of 0.5 to 4 with respect to the total binder in the layer opposite to the photosensitive layer side.
It is preferable to contain 0%.

The material of the matting agent used in the present invention may be either an organic substance or an inorganic substance. For example, as the inorganic substance, silica described in Swiss Patent No. 330,158, glass powder described in French Patent No. 1,296,995, and alkali described in British Patent No. 1,173,181, etc. An earth metal, a carbonate such as zinc, or the like can be used as a matting agent. Organic substances include US Patent Nos. 2 and 3
Starch described in No. 22,037, etc., Belgian Patent No. 62
No. 5,451 and starch derivatives described in British Patent No. 981,198, polyvinyl alcohol described in Japanese Patent Publication No. 44-3643 and the like, polystyrene or polymethacrylate described in Swiss Patent No. 330,158, etc., Organic matting agents such as polyacrylonitrile described in US Pat. No. 3,079,257 and polycarbonate described in US Pat. No. 3,022,169 can be used.

The shape of the matting agent may be either a fixed shape or an amorphous shape, but a fixed shape is preferable, and a spherical shape is preferably used. The size of the matting agent is represented by the diameter when the volume of the matting agent is converted into a spherical shape. In the present invention, the particle size of the matting agent refers to the spherically converted diameter.

The matting agent used in the present invention preferably has an average particle size of 0.5 to 10 μm, more preferably 1.0 to 8.0 μm. The coefficient of variation of the particle size distribution is preferably 50% or less,
Further, it is preferably 40% or less, particularly preferably 3%.
The matting agent is 0% or less.

Here, the variation coefficient of the particle size distribution is a value represented by the following formula. (Standard deviation of particle size) / (average value of particle size) × 100 These matting agents may be contained in any constituent layer, but in order to achieve the object of the present invention, they are preferably seen from the support. Is the outermost layer.

The method for adding the matting agent according to the present invention may be a method in which the matting agent is preliminarily dispersed in a coating solution and then applied.
A method of spraying the matting agent after applying the coating solution and before the completion of drying may be used. When adding a plurality of types of matting agents, both methods may be used in combination. The amount of the matting agent added can be appropriately determined at a level at which haze does not become a problem depending on the size of the matting particles.
It is preferable to use 0.01 mg / m ^{2 to 1} g / m ² . Excessive addition causes a problem of haze deterioration.

The heat-developable photosensitive material of the present invention forms a photographic image by a heat-development treatment, and comprises a reducible silver source (organic silver salt), a catalytically active amount of silver halide, a reducing agent, and if necessary. Accordingly, the photothermographic image-forming material preferably contains a toning agent that suppresses the tone of silver in a state of being dispersed in an organic binder matrix. The photothermographic image-forming material of the present invention is stable at room temperature, but at a high temperature (for example, 80 to 80 ° C) after exposure.
It is developed by being heated to 140 ° C. When heated, silver is produced through a redox reaction between an organic silver salt (which functions as an oxidizing agent) and a reducing agent. This redox reaction is promoted by the catalytic action of the latent image generated on the silver halide upon exposure. The silver produced by the reaction of the organic silver salt in the exposed areas provides a black image, which contrasts with the unexposed areas and forms an image. This reaction process proceeds without supplying a treatment liquid such as water from the outside.

The photothermographic image-forming material of the present invention has at least one photosensitive layer on a support. Although only the photothermographic layer may be formed on the support, it is preferable to form at least one non-photosensitive layer on the layer.

In order to control the amount or wavelength distribution of light passing through the photosensitive layer, a filter dye layer is formed on the same side as the photosensitive layer and / or an antihalation dye layer, a so-called backing layer, is formed on the opposite side. Alternatively, the photosensitive layer may contain a dye or a pigment.

The photothermographic image-forming material of the present invention preferably contains an antifoggant. Mercury compounds known as effective antifoggants, such as US Pat. No. 3,589,903, are environmentally unfavorable. Therefore, non-mercury antifoggants have been studied for a long time. Non-mercury antifoggants include, for example, US Pat.
Antifoggants as disclosed in 546,075 and 4,452,885 and JP-A-59-57234 are preferable.

Examples of preferable antifoggants include paragraphs [0062] to [0063] in JP-A No. 9-90550.
Are the compounds described in. In addition, other suitable antifoggants include US Pat. No. 5,028,523 and EP 600,587, 605,981,
No. 631,176.

The photothermographic image-forming material of the present invention includes, for example, JP-A-63-159841 and JP-A-60-140335.
No. 63-231437, No. 63-259651.
No. 63-304242, No. 63-15245,
U.S. Pat. Nos. 4,639,414 and 4,740,4
No. 55, No. 4,741,966, No. 4,751,
The sensitizing dyes described in No. 175 and No. 4,835,096 can be used. Useful sensitizing dyes used in the present invention are, for example, Research Disclosure 17
643 IV-A (Dec. 1978, p.23), 18
It is described in the literature described or cited in Item 431X (p.437, August 1979). In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of various scanner light sources can be preferably selected and used. For example, JP-A-9-
34078, 9-54409, 9-80679.
The compounds described in No. 10 are preferably used.

In the present invention, in the photothermographic image forming material,
If necessary, a sensitizer, an organic or inorganic filler, a surfactant, an anti-staining agent, a UV absorber, an antioxidant, a water-proofing agent, a dispersant, a stabilizer, a plasticizer, a coating aid, an eraser. A foaming agent, a fluorescent dye, a metal salt of higher fatty acid, etc. may be added.

The heat-developable photosensitive layer may be composed of a plurality of layers, and the sensitivity may be a high sensitivity layer / low sensitivity layer or a low sensitivity layer / high sensitivity layer for adjusting gradation. Various additives are the photosensitive layer,
It may be added to either the non-photosensitive layer or the other forming layer.

As the support, a support such as paper, synthetic paper, non-woven fabric, metal foil or plastic film can be used, and a composite sheet in which these are combined may be optionally used. (Support) As the support, a support such as polyethylene terephthalate, polyethylene naphthalate or syndiotactic polystyrene is preferred, and biaxially stretched or heat-fixed is highly optically isotropic and usually has good dimensional stability.
Those having a thickness of 0 to 400 μm are preferable.

(Image exposure) As an exposure method, Japanese Patent Laid-Open No.
No. 304869, No. 9-311403 and JP-A-2
Laser exposure can be carried out by the method described in 000-10230. For exposure to the photothermographic image forming material of the present invention, it is desirable to use a light source suitable for the color sensitivity imparted to the photosensitive material. For example, when the sensitive material is made to be sensitive to infrared light, it can be applied to any light source in the infrared light range, but the laser power is high and the photothermographic material is transparent. Infrared semiconductor lasers (780 nm, 820 nm) are more preferably used from the standpoints of capability and the like.

(Heat Developing Device) The device for developing the photothermographic image forming material is disclosed in JP-A-11-65067 and 11-7.
The devices described in 2897 and 11-84619 can be used.

[0098]

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

Example 1 Preparation of undercoated photographic support Commercially available biaxial stretching heat colored blue to 0.170 with optical density
Fixed 175 μm thick polyethylene terephthalate
Corona discharge treatment (8W / m ²・ Minute)
Apply the undercoat coating solution a-1 below on one side and dry.
Dried to form undercoat A-1, and apply the following undercoat on the opposite side.
Coating solution b-1 is applied and dried to form an undercoat layer on the back layer side.
It was set to B-1. Undercoat coating liquid a-1   Butyl acrylate (30% by mass)     t-Butyl acrylate (20 mass%)     Styrene (25% by mass)     2-hydroxyethyl acrylate (25% by mass)     Copolymer latex liquid (solid content 30%) 0.08 g / m²   Hexamethylene-1,6-bis (ethylene urea) 0.008 g / m² Undercoat coating liquid b-1   Butyl acrylate (40% by mass)     Styrene (20 mass%)     Glycidyl acrylate (40% by mass)     Copolymer latex liquid (solid content 30%) 0.08 g / m²   Hexamethylene-1,6-bis (ethylene urea) 0.008 g / m² Subsequently, the upper surface of the undercoat layer A-1 and the undercoat layer B-1
8 W / m²・ Corona discharge for minutes, undercoat layer A-
On top of 1, the undercoating upper layer coating liquid a-2 below was formed into a dry film thickness.
It is applied as an undercoat upper layer A-2 so as to have a thickness of 0.1 μm,
On the undercoat layer B-1, the following undercoat upper layer coating liquid b-2
It was applied as an undercoat upper layer B-2. Undercoat Upper layer coating liquid a-2   Gelatin 0.4 g / m²   Silica particles (average particle size 2 μm) 0.01 g / m² Undercoat upper layer coating liquid b-2   Styrene-butadiene copolymer latex liquid (solid content 20%)                                                      0.08g / m²   Polyethylene glycol (mass average molecular weight 900) 0.036 g / m²   Silica particles (average particle diameter 3 μm) 0.01 g / m² Preparation of photosensitive silver halide emulsion A 7.5 g of inert gelatin and bromine carbonate in 900 ml of water.
Dissolve 10 mg of thorium to a temperature of 35 ° C and a pH of 3.0
After combining, 370 ml of an aqueous solution containing 74 g of silver nitrate was added.
This is equivalent to (98/2) molar ratio of potassium bromide and iodide
Keep 370 ml of an aqueous solution containing potassium at pAg 7.7.
By the way, 10 minutes by controlled double jet method
Added. Then 4-hydroxy-6-methyl-
0.3 g of 1,3,3a, 7-tetrazaindene was added
The pH was adjusted to 5.0 with NaOH and the average particle size was adjusted to 0.
06 μm, variation coefficient of particle size 8%, [100] surface ratio
Cubic silver iodobromide grains having a rate of 87% were obtained. Zera to this emulsion
Phenoxy after desalting by coagulating sedimentation using a tin coagulant
0.1 g of ethanol was added, pH 5.9, pAg 7.5
To obtain a photosensitive silver halide emulsion A. Preparation of powdered silver halide-containing organic silver salt A To 4720 ml of pure water, behenic acid 111.4 g, arachidi
Dissolve 83.8 g of acid and 54.9 g of stearic acid at 80 ° C.
I understand. Next, while stirring at high speed, 1.5M sodium hydroxide
540.2 ml of an aqueous solution of lithium was added and stirred sufficiently.
Next, after adding 6.9 ml of concentrated nitric acid, the mixture was cooled to 55 ° C.
A sodium oxalate solution was obtained. Of the organic acid sodium salt solution
While maintaining the temperature at 55 ° C, the above-mentioned photosensitive silver halide milk
Add agent A (containing 0.038 mol of silver) and 450 ml of pure water.
The mixture was added and stirred for 5 minutes. Then 1M silver nitrate solution 760.6
Add ml over 2 minutes, stir for an additional 20 minutes and filter
To remove water-soluble salts. After that, the conductivity of the filtrate
Rinse with deionized water to 2 μS / cm, then
Fluidized bed dried. Preparation of photosensitive layer coating liquid On the undercoating upper layer A-2 of the above-mentioned undercoated support
The photosensitive layer surface side was coated, and the undercoat was formed on the upper layer B-2 (with the photosensitive layer).
On the other side, apply the following back layer surface and apply the following layers in order.
Next, it was formed and a sample was prepared. In addition, the drying is 75 ℃, 1 respectively
I went in minutes.

<< Coating on Photosensitive Layer Side >> First Layer: Antihalation Layer (AH) Layer Binder PVB-1 (Polymerization degree 600) 1.2 g / m ² Antihalation Dye C1 2 × 10 ⁻⁵ mol / m ² 2 layers: Photosensitive layer The photosensitive layer was prepared by adding the following composition to a methyl ethyl ketone solution to prepare a coating solution.

Powdered silver halide-containing organic silver salt A (amount of silver: 1.2 g / m ² ) Binder PVB-1 (polymerization degree: 600) 5.6 g / m ² Polymer of the present invention (described in Table 1) ) 9.3 × 10 ⁻⁴ mol / m ² sensitizing dye A1 2.1 × 10 ⁻⁴ mol / Ag1 mol antihalation dye C1 1.1 × 10 ⁻⁵ mol / m ² antifoggant 1: pyridinium hydrobromide Paburomido 0.3 mg / m ² antifoggant 2: isothiazolone 1.2 mg / m ² antifoggant 3: 5-methyl-benzotriazole 120 mg / m ² developer (1,1-bis (2-hydroxy-3,5 -Dimethylphenyl) -3,5,5-trimethylhexane) 3.3 mmol / m ² Third layer: photosensitive layer protective layer Binder (cellulose acetate butyrate) 1.2 g / m ² Silica matting agent (average particle size 3 μm) ) .5g / m ² "back layer surface coating" first layer: a back layer binder PVB-1 (degree of polymerization 600) 1.2 g / m ² Dye C1 (AH and the same as the photosensitive layer) 70 mg / m ² Second layer: Back layer Protective layer Cellulose acetate butyrate 0.8 g / m ² Matting agent (PMMA: average particle size 3 μm) 0.02 g / m ² Surfactant (N-propyl perfluorooctyl sulfonamide acetic acid) 0.02 g / m ²

[0102]

[Chemical 10]

Evaluation of Photographic Performance The conditions of exposure and development were 81 for photothermographic image forming materials.
It was exposed with a laser sensitometer having a semiconductor laser of 0 nm, and then subjected to heat development treatment at 120 ° C. for 8 seconds using a heating drum. At that time, exposure and development are 25 ° C. and relative humidity is 50.
I went to a room where the humidity was adjusted to%. The sensitivity and fog of the obtained image were evaluated by an automatic densitometer. Sensitivity was determined as the reciprocal of the ratio of the exposure dose that gives a density 0.3 higher than fog. The relative sensitivity is shown with the sensitivity of the sample 101 being 100.
For the measurement of fog, an unexposed sample was thermally developed and the density was measured.

As for the optical fog, the fog density was measured after the photothermographic image-forming material was allowed to stand in a 10,000 lux Schaukasten for 10 hours.

For the evaluation of scratch resistance, the sample was rubbed while applying a load of 5 kPa with an uneven roller having a depth of 3 μm, and the scratch level was visually evaluated. The scratch-free level was evaluated as 5, the level with the most scratches was 1, and the level of medium and practically no problem was evaluated as 3.

The results are shown in Table 1.

[0107]

[Table 1]

Comparative Compound 1: Triethylamine From Table 1, when the polymer of the present invention is used (the constitution of the invention of claim 1 of the present invention), the fog is low in the photographic characteristics, the sensitivity is high, and particularly the light fog resistance is excellent. It can be seen that a photothermographic image forming material which is hard to be scratched can be obtained.

Example 2 A photothermographic image forming material was prepared in the same manner as in Example 1, except that
Here, a sample was prepared by changing the composition of the compound represented by the general formula (2) used as the binder as shown in Table 2. The composition was changed by saponifying polyvinyl acetate having a degree of polymerization of 600 so that the degree of saponification was 70 to 99%, polyvinyl alcohols having different degrees of saponification were prepared in advance, and this was reacted with butyraldehyde for butyralization. The conditions for acetalization were to add 10% hydrochloric acid to a 30% aqueous solution of saponified polyvinyl alcohol (calculated as solid content) to obtain a pH of 1.
5. The temperature was set to 86 ° C., butyraldehyde in an amount corresponding to the degree of acetalization was added over 10 minutes, and the reaction was performed for 6 hours. The precipitated product was collected by filtration, dried, and washed with ethanol for purification. did. The acetalization degree (d ₁ ) was calculated from the remaining hydroxyl value. Performance evaluation was performed in the same manner as in Example 1.

The results are shown in Table 2.

[0111]

[Table 2]

From Table 2, when the polymer of the present invention and the butyral of the present invention (a polymer represented by the general formula (2)) are used as the binder (constitution of the invention of claim 3 of the present invention), particularly It can be seen that the fog resistance and the scratch resistance can be improved.

Example 3 A sample was prepared in the same manner as in Example 2, but the binder used here was intermolecular acetalized. For the intermolecular acetalized product, saponified polyvinyl alcohol is dissolved in an aqueous acetone solution (water: acetone = 1: 1) so that the solid content concentration is 76%, the pH is set to 1.5, and the temperature is set to 96 ° C. , Butyraldehyde in an amount corresponding to the degree of acetalization was added dropwise over 10 minutes.

The intermolecular ratio was determined by calculating the molecular weight by the viscosity method. Solid content that neglects acetalization between molecules 1
Acetalization of saponified polyvinyl alcohol of% concentration is carried out, the molecular weight is obtained in advance by the viscosity method, and the ratio of acetalization between molecules is obtained from the difference between the molecular weight of acetalization in polyvinyl alcohol having a high solid content. It was The photographic performance of the obtained sample was evaluated in the same manner as in Example 1.

The results are shown in Table 3.

[0116]

[Table 3]

From Table 3, when the polymer of the present invention and the polymer containing the intermolecular acetalized polymer among the polymers represented by the general formula (2) are used (the composition of the invention of claim 4 of the present invention, ), A photothermographic image forming material having particularly excellent light fog resistance and scratch resistance can be obtained.

Example 4 A sample was prepared in the same manner as in Example 1, except that an undercoated support was used for coating the photosensitive layer side, and latex and gelatin were used as the binder on the photosensitive layer side. Application was performed.

That is, a 4% (mass / V) gelatin aqueous solution 1
A liquid prepared by adding 400 ml of an emulsion of 20% (mass / V) latex (described in Table 4) to L was prepared in advance, and additives other than the binder were added so that the coating amount was the same as in Example 1. did. The amount of gelatin applied was 0.4 g / m ² , and the amount of latex applied was 0.8 g / m ² .

As a binder comparison compound, a degree of polymerization of 500,
Polyvinyl alcohol (PVA *) having a saponification degree of 99% was used.

Performance evaluation was performed in the same manner as in Example 1. The results are shown in Table 4.

[0122]

[Table 4]

From Table 4, it can be seen that even when the polymer of the present invention is used in the aqueous coating using a latex as the binder (the constitution of the invention of claim 5 of the present invention), the light fog resistance and the scratch resistance are excellent. .

Example 5 A sample was prepared in the same manner as in Example 1, except that the cross-linking agents shown in Table 5 below were used. The amount used was 0.02 mmol / m ² in the binder of the photosensitive layer.

The results are shown in Table 5.

[0126]

[Table 5]

From Table 5, when the polymer and the crosslinking agent of the present invention are used (the constitutions of the inventions of claims 6 and 7), fog is low in the photographic characteristics, light fog resistance is excellent, and scratches are less likely to occur. It can be seen that a photothermographic imaging material can be obtained.

[0128]

According to the present invention, a photothermographic image forming material having high sensitivity and low fog and excellent photographic performance is provided, and more particularly, a photothermographic image forming material having improved light fog resistance after thermal development is provided. can do. Further, it is possible to provide a photothermographic image forming material having high film strength and being hardly scratched.

Claims (7)

[Claims] 1. A photothermographic image-forming material having at least a photosensitive layer containing a photosensitive silver halide grain, an organic silver salt, a reducing agent for the organic silver salt, and a binder on a support, wherein 1) A photothermographic image forming material containing a polymer obtained by copolymerizing a monomer unit having a photofogging suppressing group represented by 1) and a vinyl monomer unit having no photofogging suppressing group. [Chemical 1] (In the formula, R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, V ₁ represents a polymerizable vinyl group, and L ₁ represents a divalent linking group.) 2. The number average molecular weight of the polymer is 1,000 to 50.
The photothermographic image-forming material according to claim 1, which has a glass transition point (Tg) of 5 to 100 ° C. 3. The photothermographic image-forming material according to claim 1, wherein at least one of the binders is a polymer represented by the following general formula (2). [Chemical 2] (In the formula, R ¹ and R ² each represent an alkyl group. D
1, d2 and d3 represent the monomer composition mass ratio (mass%), d1 is 20 to 96 mass%, d2 is 1 to 40 mass%.
And d3 represent 0.1 to 40% by mass, and d1 + d2 +
d3 is 100. ) 4. The polymer represented by the general formula (2) is 0.1 to 20 mass% of a polymer represented by the general formula (2) in which at least one is acetalized between the molecules.
The photothermographic image forming material according to claim 1, wherein the photothermographic image forming material is contained. 5. The binder of the photosensitive layer or a layer adjacent to the photosensitive layer contains a latex using at least one selected from styrene, butadiene and acrylate as a monomer unit. Item 1
5. The photothermographic image-forming material according to any one of items 4 to 4. 6. The binder according to claim 1, wherein at least one crosslinking agent selected from an isocyanate compound, a vinylsulfonyl compound, an epoxy compound and an alkoxysilane compound is added to the binder. The photothermographic image-forming material as described in any one of items. 7. The photothermographic image-forming material according to claim 6, wherein the alkoxysilane compound is an alkoxysilane compound represented by the following general formula (3). [Chemical 3] (In the formula, R ³ represents an alkyl group, R ⁴ represents an aromatic group or a heterocyclic group, L ₂ represents a divalent linking group, m and n are integers of 1 to 3, and m + n = 4)