JP2005091841A - Photothermographic imaging material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an excellent photothermographic imaging material having high sensitivity and low fog with respect to photographic performances, and also to provide a photothermographic imaging material excellent in storage stability before development (raw stock preservability) and in storage stability after development (image preservability). <P>SOLUTION: In the photothermographic imaging materials with a photosensitive layer containing photosensitive silver halide grains, an organic silver salt, a reducing agent and a binder, formed on a support, a protective layer on the photosensitive layer, and a backing layer on a side of the support opposite to a side with the photosensitive layer, a compound represented by the formula (1) is contained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a photothermographic image forming material that forms an image by thermal development, and more particularly to a photothermographic image forming material that can obtain high sensitivity and low fog and is excellent in storage stability.

  In recent years, there has been a strong demand for photothermographic materials that do not generate waste liquids due to wet processing in terms of environmental protection and workability in the medical and printing fields. In particular, high-resolution and clear black images can be formed by thermal development. There is a need for techniques relating to photothermographic materials that can be used for photographic technology. Since these photothermographic materials are usually developed at a temperature of 80 ° C. or higher, they are called photothermographic image forming materials.

  Conventionally, this type of photothermographic image-forming material has been provided with a photosensitive layer containing highly sensitive photosensitive silver halide grains spectrally sensitized with a dye, an organic silver salt and a reducing agent, and light irradiated to the photosensitive layer. It is composed of an irradiation prevention layer (AI layer) or a backing layer (BC layer) provided on the opposite side of the support that prevents the material from passing through without being absorbed and diffusely reflected at the interface, intermediate layer, adhesive layer, etc. of the support. In addition, a protective layer is provided on the photosensitive layer or the BC layer to prevent scratches during handling.

  In general, the photothermographic image forming material is easy to process because it produces an image only by heat development after exposure. However, since there is no fixing step, it is important to improve the storage stability of the image after development. In order to improve the storage stability after development, it is preferable to develop the image at a high temperature so that an image appears. However, if the temperature is too high, fog is likely to occur and the sensitivity is lowered. Therefore, development is generally performed at a temperature around 120 ° C. ± 10 ° C. The use of a mercapto compound to reduce fog is disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-19681 (Patent Document 1). However, mercapto compounds have little effect of suppressing fogging, and it is difficult to obtain high sensitivity, and there is a limit to improving storage stability. A polyhalomethane compound used to suppress the occurrence of baked-out silver due to exposure to Schaukasten at the time of image interpretation after development processing is effective for fog suppression and raw storage stability. Although disclosed in 2), there is a limit to its use and effect because sensitivity decreases when the amount used is large. In order to improve the storage stability, attempts have been made to use a compound known as a crosslinking agent for the binder, but it has not been sufficient.

Certain compounds of phenol derivatives are said to be good for improving fog, sensitivity, storage stability and the like as disclosed in JP-A-2003-7592 (Patent Document 3), but they are not sufficient. Attempts have been made to search for free radical scavengers as a method of suppressing fog generation during storage, but no good one has been found.
JP 2000-199681 pages 1 to 20 JP-A-9-319022, pages 1 to 22 JP-A-2003-7592 pages 1-6

  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 excellent in photographic performance with high sensitivity and low fog. A second object of the present invention is to provide a photothermographic image-forming material that is excellent in preservative storage (also referred to as raw preservability) and post-development preservability (also referred to as image preservability).

The above object of the present invention is achieved by the following configurations.
(Claim 1)
A photosensitive layer containing photosensitive silver halide grains, an organic silver salt, a reducing agent and a binder is provided on the support, and a protective layer is provided on the photosensitive layer, on the opposite side of the support from the side having the photosensitive layer. A photothermographic image forming material having a backing layer, comprising a compound represented by the following general formula (1):

(In the formula, R ₁ represents a hydrogen atom or a hydroxyl group, and R _{2 to} R ₅ are each a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, an aryl group, a heterocyclic group, an acyl group, an alkoxycarbonyl group. Group, aryloxycarbonyl group, cyano group, carboxyl group, alkoxy group, aryloxy group, acyloxy group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group, carbamoyl group, mercapto group or alkylthio group. Z represents a heterocyclic group selected from Z _{1 to} Z ₉ , and J _{1 to} J ₁₀ each represents a group having the same meaning as the group represented by R _{2 to} R _5. )
(Claim 2)
2. The photothermographic image forming material according to claim 1, wherein the photosensitive layer or a layer adjacent to the photosensitive layer contains a phthalazine compound.
(Claim 3)
3. The photothermographic image-forming material according to claim 1, wherein a polyhalomethane compound is contained in the photosensitive layer or a layer adjacent to the photosensitive layer.
(Claim 4)
The reducing agent contained in the photosensitive layer or a layer adjacent to the photosensitive layer is a bisphenol compound, and the bisphenol compound has at least one unsaturated group in a group for bonding two phenol groups. The photothermographic image-forming material according to any one of claims 1 to 3, wherein
(Claim 5)
The photothermographic image formation according to any one of claims 1 to 4, wherein the crosslinking agent that crosslinks the binder of the photosensitive layer or a layer adjacent to the photosensitive layer is an isocyanate compound or a vinyl sulfone compound. material.

  According to the present invention, it is possible to provide a photothermographic image forming material excellent in photographic performance with high sensitivity and low fog. Further, it is possible to provide a photothermographic image forming material that is excellent in storage stability before development (raw storage stability) and storage stability after development (image storage stability).

  Hereinafter, although the best mode for carrying out the present invention will be described, the present invention is not limited to these.

  The photothermographic image-forming material of the present invention usually comprises at least two layers comprising at least one photosensitive layer and a layer adjacent to the photosensitive layer on a support, and is provided on the opposite side of the photosensitive layer. It is preferable that a BC layer, a protective layer thereof, and the like are included. The photosensitive layer of the photothermographic image forming material contains photosensitive silver halide grains that may be sensitized with a spectral sensitizing dye, and the photosensitive layer or an adjacent layer thereof is an organic silver serving as a silver source. It is preferable that the reducing agent for developing a salt and silver salt to form a silver image is contained, and the compound represented by the general formula (1) of the present invention is contained. The photosensitive layer of the photothermographic image forming material and the adjacent layer of the photosensitive layer contain a hydrophilic binder or a hydrophobic binder that provides a field for heat development reaction. In the photothermographic image forming material, it is preferable to provide an AI layer or a BC layer containing a dye for preventing irradiation or preventing halation as necessary.

  Hereinafter, the compound represented by formula (1), the phthalazine compound, the polyhalomethane compound, the reducing agent, and the crosslinking agent contained in the photothermographic image forming material of the present invention will be described in order. The photosensitive silver halide grains contained in the photosensitive layer of the photothermographic image forming material, the organic silver salt contained in the photosensitive layer or its adjacent layer, the reducing agent, the high content contained in the photosensitive layer or its adjacent layer. The molecular binder and the like will be further described later.

(Compound represented by the general formula (1))
In the compound represented by the general formula (1), R ₁ represents a hydrogen atom or a hydroxyl group, and R _{2 to} R ₅ are each a hydrogen atom, a halogen atom (for example, a chlorine atom, a bromine atom, etc.), straight chain, branched or cyclic. Alkyl groups (for example, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, t-butyl group, n-hexyl group, n-octyl group, iso-octyl group, n-dodecyl group) Group, adamantyl group, cyclohexyl group, cyclobutyl group etc.), aryl group (eg phenyl group etc., naphthyl group etc.), heterocyclic group (eg pyridyl group, quinolyl group, imidazolyl group, thiazolyl group, thiadiazolyl group etc.), Acyl group, alkoxycarbonyl group, aryloxycarbonyl group, cyano group, carboxyl group, alkoxy group (for example, methoxy group, ethoxy group, Butoxy group, octoxy group, dodecyloxy group, etc.), aryloxy group (eg, phenoxy group, naphthoxy group, etc.), acyloxy group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group, carbamoyl group, It represents a group selected from a mercapto group and an alkylthio group (for example, a methylthio group, an ethylthio group, etc.).

Z represents a group selected from nine heterocyclic groups of Z _{1 to} Z ₉ , and J _{1 to} J ₁₀ are groups having the same meaning as the group represented by R _{2 to} R ₅ . A method for synthesizing these compounds can be synthesized with reference to JP-A-8-225449.

The compound is preferably used in an amount of 1 × 10 ⁻⁸ mol to 1 × 10 ⁻² mol relative to the silver halide. Addition method is dissolved in water, alcohol (eg, methanol, ethanol, isobutyl alcohol, etc.), tons (eg, acetone, methyl ethyl ketone, isobutyl ketone, etc.), aromatic organic solvent (eg, toluene, xylene, etc.) and added. It can also be added as a fine particle. In this case, jet mill dispersion, ultrasonic dispersion or homogenizer dispersion is carried out to form fine particles of 1 μm or less, and if necessary, a surfactant or viscosity modifier can be added and dispersed in water or an organic solvent. . The addition amount is preferably added to the coating solution in the range of 1/1000% by mass to 60% by mass, particularly preferably in the range of 1/100% by mass to 30% by mass, and the addition amount is adjusted appropriately within this range. Can be used.

  Specific examples of the compound represented by the general formula (1) used in the present invention are shown below, but are not limited thereto.

(Phthalazine compound)
The phthalazine compound can be obtained by introducing various substituents into the phthalazine ring.

  A preferred phthalazine compound can be represented by the general formula (2).

In the formula, R ^{2 to} R ⁷ are each a hydrogen atom, a halogen atom, a cyano group, a hydroxy group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryl group, or a heterocyclic group, each of which may have a substituent. Represents. The function as the group of R ^{2 to} R ⁷ may be a group such as a group that controls diffusibility, a non-diffusible group, a diffusible group, an adsorbing group, or an acidic group. As for carbon number of an alkyl group, an alkenyl group, an alkynyl group, and an alkoxy group, 1-60 are preferable, Most preferably, it is 1-40. When the number of carbon atoms is large, it is difficult to obtain good effects on fog suppression, color tone, and storage stability. Specific examples of these groups may be the same groups as those on the ring of the general formula (1). The method for synthesizing phthalazine can be synthesized with reference to WO96 / 05176A. Specific examples of preferred phthalazine compounds are shown below.

(Polyhalomethane compound)
The polyhalomethane compound used in the present invention is preferably a compound having at least one trihalomethane group in one molecule, and the trihalomethane group is substituted on an aliphatic group, a hydrocarbon aromatic ring group, Substitution is introduced into the aromatic heterocyclic group. The hydrocarbon aromatic ring or aromatic heterocycle of these cyclic groups may be further linked to a hydrocarbon aromatic ring or aromatic heterocycle via a divalent linking group. The hydrocarbon aromatic ring group is preferably a phenyl group or a naphthalene group, and on these rings, a rogen atom (for example, chlorine atom, bromine atom, fluorine atom, etc.) alkyl group (for example, methyl group, ethyl group, butyl group) , An octyl group, a dodecyl group, an octadecyl group, etc.). Examples of the aromatic heterocyclic group include a pyridine ring group, a pyrimidine ring group, a quinoline ring group, a furan ring group, a thiophene ring group, an imidazole ring group, a triazole ring group, an oxazole ring group, a thiazole ring group, a thiadiazole ring group, Examples thereof include an oxadiazole ring group, and these rings may have the same substituent as in the case of the hydrocarbon aromatic ring group. Further, a group for imparting diffusion resistance or a group that promotes adsorption to silver halide may be substituted on the hydrocarbon aromatic ring or aromatic heterocycle. The group adjacent to the trihalomethane group is preferably a sulfonyl group or a carbonyl group, but may be directly bonded onto a hydrocarbon aromatic ring or aromatic heterocycle, and the bonding method is not limited. The hydrocarbon aromatic ring or aromatic heterocycle may be reduced to be a non-aryl saturated ring. The halogen atom of the trihalomethane group is preferably a bromine atom, but may be chlorine, fluorine, iodine, or a combination thereof. Examples of the compound having a preferred structure include compounds represented by the following general formula (3).

In the formula, X ¹ , X ² and X ³ are each independently a hydrogen atom, a halogen atom (eg, bromine atom, chlorine atom, etc.), an acyl group (eg, acetyl group, benzoyl group, etc.) or an alkoxycarbonyl group (eg, methoxy). Carbonyl group, ethoxycarbonyl group, etc.), aryloxycarbonyl group (phenoxycarbonyl group, naphthyloxy bank carbonyl group, etc.), sulfonyl group, alkyl group (eg, methyl group, ethyl group, etc.) or aryl group (eg, phenyl group, Naphthyl group), at least two of which are halogen atoms. Z ₂ represents a cyclic group. L ₁ represents —C (═O) —, —SO— or —SO ₂ —, and p represents 0 or 1.

Z ₂ represents a cyclic group, and examples of the cyclic group include a saturated or unsaturated monocyclic or optionally condensed hydrocarbon cyclic group, preferably a monocyclic or bicyclic group having 6 to 30 carbon atoms. Group (for example, adamantyl group, cyclobutyl group, cyclopropyl group, cyclopentyl group, cyclooctyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cyclopentenyl group, cyclohexenyl group, phenyl, naphthyl group, etc.), more preferably cyclopentyl. Group, a cyclohexyl group, a cyclohexenyl group, a cyclopentenyl group, a phenyl group and a naphthyl group, more preferably a phenyl group.

When Z ₂ is a heterocyclic group, it is a 3- to 10-membered saturated or unsaturated heterocyclic group containing at least one atom of N, O or S, which may be monocyclic, A condensed ring may be formed with other rings. The heterocyclic group is preferably a 5- or 6-membered saturated or unsaturated heterocyclic group which may have a condensed ring, more preferably a 5- or 6-membered aromatic which may have a condensed ring. It is a heterocyclic group. More preferably a 5- or 6-membered saturated or unsaturated heterocyclic group which may have a condensed ring containing a nitrogen atom, particularly preferably a condensed ring containing 1 to 4 nitrogen atoms. A good 5- or 6-membered unsaturated heterocyclic group. Examples of the heterocyclic ring in such a heterocyclic group include imidazole, pyrazole, pyridine, pyrimidine, pyrazine, pyridazine, triazole, triazine, indole, phospholene, purine, thiadiazole, oxadiazole, quinoline, phthalazine, naphthyridine, quinoxaline, and quinazoline. Cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, thiazole, oxazole, benzimidazole, benzoxazole, benzthiazole, indolenine, tetrazaindene, more preferably imidazole, pyridine, pyrimidine, pyrazine, pyridazine, triazole, Triazine, thiadiazole, oxadiazole, quinoline, phthalazine, naphthyridine, quinoxaline, quinazo , Tetrazole, thiazole, oxazole, benzimidazole, benzoxazole, benzthiazole, tetrazaindene, more preferably imidazole, pyridine, pyrimidine, pyrazine, pyridazine, triazole, triazine, thiadiazole, quinoline, phthalazine, naphthyridine, quinoxaline, Rings such as quinazoline, cinnoline, tetrazole, thiazole, benzimidazole, and benzthiazole are exemplified, and rings such as piperidine, piperazine, pyridine, thiadiazole, quinoline, and benzthiazole are particularly preferable. Specific examples of these compounds are listed below.

The phthalazine compound, polyhalomethane compound, bisphenol compound, crosslinking agent and the like used in combination with the compound represented by the general formula (1) of the present invention are 1 × 10 to 1 mol of the compound represented by the general formula (1) of the present invention. It is preferable to add from ⁻² mol to 1 × 10 ³ mol. The addition position is not limited to the photosensitive layer in which silver halide exists, and may be an adjacent layer or an undercoat layer. The addition method can be performed in the same manner as the compound represented by the general formula (1). Preferred specific examples are shown below.

  Next, organic silver salts, reducing agents, photosensitive silver halide grains, binders, dyes, matting agents and other supports used in the photothermographic image forming material of the present invention will be described in order.

(Organic silver salt)
The organic silver salt contained in the photothermographic image-forming material of the present invention is a reducible silver source, a silver salt of an organic acid, a silver salt of a heteroorganic acid and a silver of an acid polymer containing a reducible silver ion source. Salt or the like is used. Also useful are organic or inorganic silver salt complexes whose ligands have a total stability constant for silver ions of 4.0-10.0. Examples of silver salts are described in Research Disclosure Nos. 17029 and 29963 and include the following: silver salts of organic acids (eg, gallic acid, oxalic acid, behenic acid, arachidic acid, stearic acid, palmitic acid, Silver salt such as lauric acid).

(Reducing agent)
Examples of preferable reducing agents contained in the photothermographic image-forming material of the present invention are described in U.S. Pat. Nos. 3,770,448, 3,773,512, 3,593,863, etc. And Research Disclosure Nos. 17029 and 29963, including the following:

  Bisphenols (for example, bis (2-hydroxy-3-t-butyl-5-methylphenyl) methane, 2,2-bis (4-hydroxy-3-methylphenyl) propane), UV-sensitive ascorbic acid derivatives or 3 -A pyrazolidone etc. can be mentioned. Of these, particularly preferred reducing agents are bisphenols. Examples of the bisphenols include compounds represented by the following general formula (4).

  In the formula, R is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms (for example, a butyl group, 2,4,4-trimethylpentyl group, etc.), an unsaturated alicyclic group (preferably as a cycloalkenyl group, for example, Cyclopentenyl group, cyclohexenyl group, 2,4-dimethylcyclohexenyl group, cyclopentadienyl group, etc.), hydrocarbon aromatic ring group (for example, phenyl group, naphthyl group, etc.), or heterocyclic group (furyl group) Thiophenyl group, pyridyl group, oxazolyl group, thiazolyl group, etc.), wherein R ′ and R ″ are linear or branched alkyl groups having 1 to 5 carbon atoms (for example, methyl group, ethyl group, t-butyl) In particular, in the formula, R is preferably a cyclic group, more preferably an unsaturated cyclic group, the most preferred cyclic group being a cyclohexenyl group, and 2,4-dimethylsilane. B hexenyl group, cyclohexenyl group cyclohexylene, cyclopentadienyl group, a furyl group, preferably followed by a thiophenyl group.

  Specific examples of the compound represented by the general formula (4) are shown below. However, the present invention is not limited to the following compounds.

The amount of the reducing agent including the compound represented by the general formula (4) is preferably 1 × 10 ⁻² to 10 mol, particularly 1 × 10 ^{−2 to} 1.5 mol, per mol of silver. .

(Photosensitive silver halide grains)
The photosensitive silver halide grains contained in the photosensitive layer of the photothermographic image forming material of the present invention can be obtained by any method known in the field of photographic technology such as a single jet or double jet method, such as an ammonia emulsion. It can be prepared in advance by any method such as an acid method or an acidic method, and then mixed with the 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 grains into contact with the organic silver salt, for example, US Pat. Nos. 3,706,564 and 3rd as protective polymers for preparing photosensitive silver halide grains. , 706,565, 3,713,833, 3,748,143, British Patent 1,362,970 and polymers other than gelatin such as polyvinyl acetals. Means used, enzymatic means for degrading gelatin of photosensitive silver halide emulsions as described in GB 1,354,186, or as described in US Pat. No. 4,076,539 As described above, various means such as means for omitting the use of the protective polymer can be applied by preparing photosensitive silver halide grains in the presence of a surfactant.

  The photosensitive silver halide grains preferably have a small grain size in order to keep the white turbidity after image formation low and to obtain good image quality. The average particle size is 0.1 μm or less, preferably 0.01 to 0.1 μm, particularly preferably 0.02 to 0.08 μm. Further, the shape of the photosensitive silver halide grains is not particularly limited, and there are cubic, octahedral so-called normal crystals, non-normal crystals such as spherical, rod-like, and tabular grains. The silver halide composition is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide, and silver iodide.

  The amount of the photosensitive silver halide grains is 50% by mass or less, preferably 25 to 0.1% by mass, more preferably 15 to 0.1% by mass, based on the total amount of the photosensitive silver halide grains and the organic silver salt described later. Between. Various conditions such as reaction temperature, reaction time, reaction pressure, etc. in the step of converting a part of the organic silver salt into silver halide using the above-mentioned photosensitive silver halide grain forming component should be appropriately set according to the purpose of preparation. However, usually, the reaction temperature is −23 ° C. to 74 ° C., the reaction time is 0.1 seconds to 72 hours, and the reaction pressure is preferably set to atmospheric pressure.

  The photosensitive silver halide grains prepared by the various methods described above can be chemically sensitized by, for example, a sulfur-containing compound, a gold compound, a platinum compound, a palladium compound, a silver compound, a tin compound, a chromium compound, or a combination thereof. it can. Regarding the method and procedure of this chemical sensitization, for example, U.S. Pat. No. 4,036,650, British Patent No. 1,518,850 and the like, JP-A-51-22430, JP-A-51-78319. , 51-81124, etc. In addition, when a part of the organic silver salt is converted to photosensitive silver halide by the photosensitive silver halide grain forming component, sensitization is performed as described in US Pat. No. 3,980,482. In order to achieve this, a low molecular weight amide compound may coexist.

  These photosensitive silver halide grains include illuminance failure and metals belonging to groups 6 to 10 of the periodic table of elements for adjusting gradation, such as Rh, Ru, Re, Ir, Os, Fe, etc. Or its complex or complex ion. In particular, it is preferable to contain ions or complex ions of metals belonging to Groups 6 to 10 of the Periodic Table of Elements. As the above metal, W, Fe, Co, Ni, Cu, Ru, Rh, Pd, Re, Os, Ir, Pt, and Au are preferable. Among them, when used for a photosensitive material for printing plate making, Rh, Re, It is preferably selected from Ru, Ir, and Os. These metals can be introduced into the silver halide in the form of a complex.

The content of metal ions or complex ions is generally 1 × 10 ⁻⁹ to 1 × 10 ⁻² mol per mol of silver halide, preferably 1 × 10 ⁻⁸ to 1 × 10. ^-4 moles. The compounds providing these metal ions or complex ions are preferably added at the time of silver halide grain formation and incorporated into the silver halide grains. Preparation of silver halide grains, that is, nucleation, growth, physical ripening , May be added at any stage before or after chemical sensitization, but is preferably added at the stage of nucleation, growth and physical ripening, more preferably at the stage of nucleation and growth, most preferably Preferably, it is added at the stage of nucleation. In addition, it may be divided and added several times, or it can be uniformly contained in the silver halide grains. JP-A-63-29603, JP-A-2-306236, 3 As described in publications such as 167545, 4-76534, 6-110146, and 5-273683, the particles can be contained with a distribution. Preferably, a distribution can be provided inside the particles. These metal compounds can be added by dissolving in water or an appropriate organic solvent (for example, alcohols, ethers, glycols, ketones, esters, amides). A method in which an aqueous solution or an aqueous solution in which a metal compound and NaCl, KCl are dissolved together is added to a water-soluble silver salt solution or a water-soluble halide solution during particle formation, or the silver salt solution and the halide solution are mixed simultaneously. When adding a third aqueous solution, a method of preparing silver halide grains by a method of three-liquid simultaneous mixing, a method of adding a required amount of an aqueous solution of a metal compound to the reaction vessel during grain formation, or a silver halide preparation There is a method of adding and dissolving another silver halide grain that has been previously doped with metal ions or complex ions. In particular, a method of adding an aqueous solution of a metal compound powder or an aqueous solution in which a metal compound and NaCl, KCl are dissolved together is added to the water-soluble halide solution. When added to the surface of the silver halide grains, a necessary amount of an aqueous solution of the metal compound can be charged into the reaction vessel immediately after the formation of the silver halide grains, during or after physical ripening, or at the time of chemical ripening.

(Spectral sensitizing dye)
Spectral sensitizing dyes used in the present invention are, for example, disclosed in JP-A Nos. 63-159841, 60-140335, 63-231437, 63-259651, 63-304242, 63-15245. No. 4,639,414, US Pat. No. 4,740,455, US Pat. No. 4,741,966, US Pat. No. 4,751,175, US Pat. No. 4,835,096 Sensitizing dyes described in each specification such as No. can be used. Useful sensitizing dyes used in the present invention are described in, for example, the literature described or cited in Research Disclosure Item 17643IV-A (December 1978, p.23) and Item 1831X (August 1978, p.437). Has been. In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of various scanner light sources can be advantageously selected. For example, the compounds described in JP-A Nos. 9-34078, 9-54409, and 9-80679 are preferably used.

(binder)
The polymer binder that is a binder used in the photosensitive layer or the non-photosensitive layer of the photothermographic image forming material of the present invention is a material preferable as a place where photosensitive silver halide grains, an organic silver salt, and a reducing agent react with each other. A material preferable for the reaction in which the color dye is decolored by heat of 80 to 200 ° C. or a material from which the base generating precursor quickly generates a base by heat is selected. Examples of the polymer binder include alcohols such as methanol and ethanol, ketones such as methyl ethyl ketone and acetone, polymers used by dissolving in polar solvents including dimethyl sulfoxide and dimethylformamide, and water-dispersed polymers. Any polymer binder may be used in the photothermographic image-forming material of the present invention. Further, regarding the preferred polymer composition, the glass transition point is preferably from -20 ° C to 80 ° C, particularly preferably from -5 ° C to 60 ° C. This is because if the glass transition point is high, the temperature at which heat development is performed becomes high, and if it is low, fog is likely to occur, resulting in a decrease in sensitivity and softness.

  Examples of the polymer (polymer binder) used by being dissolved in the above polar solvent include cellulose derivatives such as hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, and ethyl cellulose, starch and derivatives thereof, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl butyral, poly Sodium acrylate, polyethylene oxide, acrylamide-acrylic acid ester copolymer, styrene-maleic anhydride copolymer, polyacrylamide, sodium alginate, gelatin, casein, polystyrene, polyvinyl acetate, polyurethane, polyacrylic acid, poly Acrylic ester, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, vinyl chloride-vinyl acetate copolymer, steel Down - butadiene - like acrylic copolymer. Further, after drying, a film is formed, and then the coating film having a low equilibrium water content is preferable. Examples of particularly low water content include poly ((methacrylic acid) such as cellulose acetate, cellulose acetate butyrate, and poly (methyl methacrylic acid). Acrylic esters), poly (acrylic acid), poly (methacrylic acid), poly (vinyl chloride), copoly (styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinyl) Acetals) (eg, poly (vinyl formal) and poly (vinyl butyral)), poly (esters), poly (urethanes), phenoxy resins, poly (vinylidene chloride), poly (epoxides), poly (carbonates) Poly (vinyl acetate), cellulose esters, poly (amino ) S can be mentioned.

(Crosslinking agent)
By forming a film alone, the binder can maintain adhesion to the lower layer and upper layer and obtain a film strength that is difficult to get scratched. However, by using a crosslinking agent, the film adhesion and film strength can be further increased. Can do. The crosslinking agent can be used by adding it to the method of adding to the undercoat layer, AI layer, photosensitive layer, protective layer, backing layer, backing protective layer and the like. From the viewpoint of the stability of the coating solution, it is preferably added using a static mixer immediately before coating, but may be added at the time of preparing the coating solution. A preferred crosslinking agent is a crosslinking agent having an isocyanate group or a vinylsulfonyl group. Particularly preferred crosslinking agents include polyfunctional crosslinking agents having at least 2, more preferably 3, isocyanate groups or vinylsulfonyl groups. JP, 2003-2874, A can be referred to for the synthesis method of a vinyl sulfonyl compound. H-1 to H-13 are shown below as preferred crosslinking agents.

(H-1) Hexamethylene diisocyanate (H-2) Trimer of hexamethylene diisocyanate (H-3) Tolylene diisocyanate (H-4) Phenylene diisocyanate (H-5) Xylylene diisocyanate Naruto

(Dye used for AI layer or BC layer if necessary)
The photothermographic image-forming material of the present invention is provided with an AI layer or BC layer for preventing irradiation or preventing halation of the photothermographic image-forming material, if necessary, and the dye used for the AI layer or BC layer is an image. Any dye can be used as long as it absorbs exposure light. Preferably, the thermodecolorable dye described in US Pat. No. 5,384,237 described above is used. If the dye used is not thermodecolorable, the amount used is limited to a range that does not affect the photothermographic image-forming material, but if it is a thermodecolorable dye, a sufficient amount of dye is necessary if necessary. Can be added.

(Matting agent)
The matting agent may be either organic or inorganic. Examples of the inorganic matting agent include silica described in Swiss Patent No. 330,158 and polystyrene or polymeta described in Swiss Patent No. 330,158. Acrylate, polyacrylonitrile described in US Pat. No. 3,079,257, polycarbonate described in US Pat. No. 3,022,169, and the like can be used.

  The shape of the matting agent may be either a regular shape or an irregular shape, but is preferably a regular shape, and a spherical shape is preferably used. The size of the matting agent is represented by a diameter when the volume of the matting agent is converted into a sphere. In the present invention, the particle size of the matting agent indicates the diameter converted into a spherical shape. 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 monodispersity of the particles is preferably 50 or less, more preferably 40 or less, and particularly preferably 20 or less. Here, the monodispersity of the particles is represented by a number obtained by dividing the standard deviation of the particle size by the average value of the particle size and multiplying by 100. The method for adding the matting agent according to the present invention may be a method in which the matting agent is dispersed and applied in advance in the coating solution, or a method in which the matting agent is sprayed after the coating solution is applied and before drying is completed. May be.

(Support)
As the support, a support such as paper, synthetic paper, non-woven fabric, metal foil, and plastic film can be used, and a composite sheet combining these may be arbitrarily used.

<Image exposure>
As the exposure method, laser exposure can be performed by the methods described in JP-A-9-304869, JP-A-9-311403 and JP-A-2000-10230.

<Heat development device>
As an apparatus for developing the photothermographic image forming material, apparatuses described in JP-A Nos. 11-65067, 11-72897 and 84619 can be used.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.

Example 1
<Preparation of underdrawn support>
A corona discharge treatment of 8 W / m ² · min is applied to both sides of a 175 μm thick polyethylene terephthalate support, and the following undercoat coating solution a-1 is applied to one surface so as to have a dry film thickness of 0.8 μm. The undercoat layer A-1 is provided by drying, and the following undercoat coating solution b-1 is applied on the opposite surface so as to have a dry film thickness of 0.8 μm and dried to form the undercoat layer B-1. Provided.

<< Undercoat coating liquid a-1 >>
Butyl acrylate (30% by mass), t-butyl acrylate (20% by mass), styrene (25% by mass), 2-
270 g of copolymer latex liquid of hydroxyethyl acrylate (25% by mass) (solid content 30%)
Hexamethylene-1,6-bis (ethylene urea) 0.8g
Finish to 1 liter with water.

<< Undercoating liquid b-1 >>
Butyl acrylate (40% by mass), styrene (20% by mass),
Copolymer latex solution of glycidyl acrylate (40% by mass) (solid content 30%) 270 g
Hexamethylene-1,6-bis (ethylene urea) 0.8g
Finish to 1 liter with water.

Subsequently, a corona discharge of 8 W / m ² · min is applied to the upper surfaces of the undercoat layer A-1 and the undercoat layer B-1, and the following undercoat upper layer coating solution a is applied on the undercoat layer A-1. -2 is applied and dried to a dry film thickness of 0.1 μm to provide an undercoat layer A-2. On the undercoat layer B-1, the following undercoat upper layer coating solution b-2 is applied to a dry film thickness of 0. A subbing upper layer B-2 having an antistatic function was applied and dried so as to have a thickness of 8 μm.

<< Undercoating upper layer coating liquid a-2 >>
Gelatin 0.4 g / m ² Mass Silica particles (average particle size 3 μm) 0.1 g
Finish to 1 liter with water 《Undercoating upper layer coating solution b-2》
Styrene-butadiene copolymer latex liquid (solid content 20%) 80g
Polyethylene glycol (mass average molecular weight 600) 6g
Finish to 1 liter with water.

<Preparation of silver halide grain emulsion A>
After dissolving 7.5 g of inert gelatin and 10 mg of potassium bromide in 900 ml of water and adjusting the temperature to 28 ° C. and pH to 3.0, bromide with a molar ratio of (98/2) to 370 ml of an aqueous solution containing 74 g of silver nitrate An aqueous solution containing potassium and potassium iodide was added over 10 minutes by the controlled double jet method while maintaining pAg 7.7. In synchronization with the addition of silver nitrate, 10 ^-6 mol / silver 1 mol of sodium salt of hexachloroiridium was added. Thereafter, 0.3 g of 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene was added, the pH was adjusted to 5 with NaOH, the average particle size was 0.036 μm, and the variation coefficient of the projected diameter area was 8%. Cubic silver iodobromide grains having a [100] face ratio of 87% were obtained. This emulsion was coagulated and precipitated using a gelatin flocculant, desalted and then 0.1 g phenoxyethanol was added to adjust the pH to 5.9 and pAg 7.5 to obtain silver halide grain emulsion A.

<Preparation of water-dispersed organic silver salt>
In 4720 ml of pure water, 111.4 g of behenic acid, 83.8 g of arachidic acid, and 54.9 g of stearic acid were dissolved at 80 ° C. Next, 540.2 ml of a 1.5 molar sodium hydroxide aqueous solution was added while stirring at high speed, and 6.9 ml of concentrated nitric acid was added, followed by cooling to 55 ° C. to obtain an organic acid sodium solution. While maintaining the temperature of the organic acid sodium solution at 55 ° C., the silver halide grain emulsion A (containing 0.038 mol of silver) and 420 ml of pure water were added and stirred for 5 minutes. Next, 760.6 ml of 1 mol silver nitrate solution was added over 2 minutes, and the mixture was further stirred for 20 minutes, and water-soluble salts were removed by filtration. Thereafter, washing with deionized water and filtration were repeated until the conductivity of the filtrate reached 2 μS / cm, and water was added to a predetermined concentration to finish.

[Production of photothermographic image forming materials]
The following layers were sequentially formed on the support provided with the undercoat layer to prepare photothermographic image forming material samples 101 to 114.

<< BC layer side application >>
On the back surface side, a BC coating layer was formed by applying and drying a coating solution prepared by adding water to an aqueous dispersion or water dispersion of the following thermodecolorable dye composition and adding the following amount.

<< BC layer application >>
Inert gelatin 1.8g / m ²
Dye C 1.2 × 10 ⁻⁵ mol / m ²
Activator: N-propyloctylsulfonamidoacetic acid
0.02 g / m ²
Dihexyl sulfosuccinic acid sodium salt 0.02 g / m ²
Hardener: 1,2-bis (vinylshonamide) ethane 0.02 g / m ²
<< Application of BC protective layer >>
Inert gelatin 1.1 g / m ²
Hardener: 1,2-bis (vinylshonamide) ethane 0.01 g / m ²
Activator: N-propyl perfluorooctylsulfonamidoacetic acid
0.02 g / m ²
Matting agent (PMMA: average particle size 5 μm) 0.12 g / m ²
<< Coating on the photosensitive layer side >>
<Application of AI layer>
Binder: PVB-1 0.4 g / m ²
Dye: C (same type as BC layer) 6 × 10 ⁻⁶ mol / m ²
<Application of photosensitive layer>
A coating solution was prepared by dissolving the following composition in a methyl ethyl ketone solvent for forming a photosensitive layer. This coating solution was kept at around 35 ° C. and dried so as to have the following weight.

Water-dispersed organic silver salt 1.36 g / m ² as the amount of silver
Binder: PVB-1 (same as AI layer) 2.6 g / m ²
Compounds represented by general formula (1): listed in Table 1 3.2 × 10 ⁻⁴ mol / m ²
(In addition, the compound of No. 13 4-41 of Table 3 in the Example of Unexamined-Japanese-Patent No. 2003-75952 was used as a comparative compound as comparative compound VB-0.)
Compounds represented by general formula (2): listed in Table 1 2.2 × 10 ⁻⁴ mol / m ²
Compounds represented by the general formula (3): listed in Table 1 1.2 × 10 ⁻⁴ mol / m ²
Spectral sensitizing dye: D 2 × 10 ⁻⁵ mol / m ²
Antifoggant-1: pyridinium hydrobromide perbromide
0.3 mg / m ²
Antifoggant-2: isothiazolone 1.2 mg / m ²
Reducing agent represented by formula (4): described in Table 1 3.3 mmol / m ²
(Note that 2,6-di-t-butyl-4-methylphenol was used as a comparative reducing agent (BP-0).)
Cross-linking agent: listed in Table 1 2 × 10 ⁻⁵ mol / m ²
(Phenylaminoethoxytrimethoxysilane (H-0) was used as a comparative crosslinking agent.)
<Surface protective layer>
A coating solution prepared by adding the following composition was applied and dried on the photosensitive layer so as to have the following weight to form a surface protective layer.

Cellulose acetate butyrate 1.2 g / m ²
4-methylphthalic acid 0.7 g / m ²
Tetrachlorophthalic acid 0.2g / m ²
Tetrachlorophthalic anhydride 0.5g / m ²
Silica matting agent (average particle size 5 μm) 0.5 g / m ²
Surfactant E 0.1 g / m ²

<Evaluation of photographic performance>
After preparing 50 samples with the size of 5 cm × 12 cm, the sample was divided into two, and one (room temperature and humidity instant sample) was sensitized for 810 nm semiconductor laser exposure in an atmosphere of 46% RH at 23 ° C. After the exposure, the sample was heated at 127 ° C. for 8 seconds, and the photographic performance of the obtained sample was evaluated. The other one is 23 ° C. RH 46% in a confidential aluminum foil packaging bag under reduced pressure (10 hPa) and heat-sealed and stored in a constant temperature room at 40 ° C. for 30 days. Similarly, the photographic performance of samples obtained by exposure and development was evaluated. The laser exposure and the development treatment were performed in a room adjusted to a humidity of 25% ± 1 ° C. and a relative humidity of 54% ± 1%.

(Evaluation of instant photo performance)
Sensitivity and fog of the above (room temperature and normal humidity immediate sample) were measured with a densitometer. Sensitivity was expressed as a relative value with the reciprocal of the ratio of the exposure amount giving a density 0.3 higher than the fog density as the sensitivity and the sample 101 as the reference (100).

(Evaluation of raw preservation)
The fog of the above (raw preservation test sample stored at high temperature in a normal humidity seal) was measured with a densitometer.

(Evaluation of image preservation)
Preservability after image development (image preservability) was measured with a densitometer after the developed sample (room temperature and humidity instant sample) was left on a shaucusten having a luminance of 10,000 lux for 10 hours.

  The results are shown in Table 1.

VB-0: No. of Table 3 in the Example of JP2003-75952A. 13-41 compound (used as a comparative compound of the compound represented by the general formula (1))
BP-0: 2,6-di-t-butyl-4-methylphenol (used as a reducing agent for comparison with the reducing agent represented by the general formula (4))
H-0: Phenylaminoethoxytrimethoxysilane (used as comparative crosslinker)
From Table 1, it can be seen that when the compound represented by the general formula (1) of the present invention is used, the photographic performance (sensitivity and fog characteristics), raw storability and image storability during development are excellent. When the compound represented by the general formula (1) of the present invention and a phthalazine, polyhalomethane, or bisphenol compound are used in combination, or further crosslinked with an isocyanate or a vinylsulfonyl crosslinking agent, the photographic performance and the raw storability and image storability during heat development It can be seen that is improved.

Claims (5)

A photosensitive layer containing photosensitive silver halide grains, an organic silver salt, a reducing agent and a binder is provided on the support, and a protective layer is provided on the photosensitive layer, on the opposite side of the support from the side having the photosensitive layer. A photothermographic image forming material having a backing layer, comprising a compound represented by the following general formula (1):

(In the formula, R ₁ represents a hydrogen atom or a hydroxyl group, and R _{2 to} R ₅ are each a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, an aryl group, a heterocyclic group, an acyl group, an alkoxycarbonyl group. Group, aryloxycarbonyl group, cyano group, carboxyl group, alkoxy group, aryloxy group, acyloxy group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group, carbamoyl group, mercapto group or alkylthio group. Z represents a heterocyclic group selected from Z _{1 to} Z ₉ , and J _{1 to} J ₁₀ each represents a group having the same meaning as the group represented by R _{2 to} R _5. ) 2. The photothermographic image forming material according to claim 1, wherein the photosensitive layer or a layer adjacent to the photosensitive layer contains a phthalazine compound. 3. The photothermographic image-forming material according to claim 1, wherein a polyhalomethane compound is contained in the photosensitive layer or a layer adjacent to the photosensitive layer. The reducing agent contained in the photosensitive layer or a layer adjacent to the photosensitive layer is a bisphenol compound, and the bisphenol compound has at least one unsaturated group in a group for bonding two phenol groups. The photothermographic image-forming material according to any one of claims 1 to 3, wherein The photothermographic image formation according to any one of claims 1 to 4, wherein the crosslinking agent for crosslinking the binder of the photosensitive layer or a layer adjacent to the photosensitive layer is an isocyanate compound or a vinyl sulfone compound. material.