JP2005227440A - Photothermographic imaging material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photothermographic imaging material having high sensitivity and little fog with respect to photographic performances and excellent in storage stability before development and in storage stability after development. <P>SOLUTION: The photothermographic imaging material has on a support a photosensitive layer containing photosensitive silver halide grains, an organic silver salt, a reducing agent and a binder, wherein the photothermographic imaging material contains an imidazole, thiazole or oxazole compound having as a substituent a benzimidazolyl, benzothiazolyl or benzoxazolyl group including an R<SB>1</SB>O- group (where R<SB>1</SB>is H or a substituent). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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

Dry processing systems are widespread in the field of medical image diagnosis by X-ray imaging.
This system absorbs the X-ray energy transmitted through the subject into the stimulable phosphor in the imaging plate, and excites and accumulates the stimulable phosphor in time series with ultraviolet rays, visible rays, or infrared rays. X-ray energy is emitted as fluorescence, and the fluorescence is photoelectrically read to obtain an electrical signal. The obtained electrical signal is converted into the intensity of laser light, and this laser light is used to produce silver halide in the photothermographic image forming material. Then, a latent image is formed and thermally developed at a temperature of 100 ° C. or higher to reproduce an X-ray image of the subject or the subject as a visible image.

  Conventionally, this type of photothermographic image-forming material absorbs a photosensitive layer containing high-sensitivity silver halide grains spectrally sensitized with a dye, an organic silver salt, and a reducing agent, and light irradiated to the photosensitive layer. It consists of an anti-irradiation layer (AI) layer that prevents the light from being diffusely reflected at the interface, intermediate layer, adhesive layer, etc. of the support, or a backing layer (BC) provided on the opposite side of the support, A protective layer is provided on the photosensitive layer and 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 lower fog is disclosed (see, for example, 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. Polyhalomethane compounds used for suppression of printout silver by exposure to Schaukasten during image interpretation after development are disclosed as compounds that are effective for fog suppression and raw storage (see, for example, Patent Document 2). There was a limit because the sensitivity decreased when there was too much. 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.

Although certain specific compounds of phenol derivatives have been disclosed (see, for example, Patent Document 3), improvements such as fogging, sensitivity, and storage stability have not been sufficient. Attempts have also been made to search for free radical scavengers as a method for suppressing the occurrence of fogging during storage, but nothing has been satisfied yet.
JP 2000-19681 A JP-A-9-319022 JP 2003-7592 A

  An object of the present invention is to provide an excellent photothermographic image forming material having high sensitivity and low fog. A second object of the present invention is to provide a photothermographic image forming material which is excellent in preservative storage (abbreviated as raw storage) and post-development storage (abbreviated as image storage).

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

(Claim 1)
In a photothermographic image-forming material having a photosensitive layer containing photosensitive silver halide grains, organic silver salt, reducing agent and binder on a support, a benzimidazolyl group, a benzthiazolyl group or a benzoxa group having an R ₁ O-group A photothermographic image-forming material comprising an imidazole compound, thiazole compound or oxazole compound having a zolyl group as a substituent.

R ₁ represents a hydrogen atom or a substituent.

(Claim 2)
The imidazole compound, thiazole compound or oxazole compound having the benzimidazolyl group, benzthiazolyl group or benzoxazolyl group having the R ₁ O— group as a substituent is a compound represented by the following general formula (1): The photothermographic image-forming material according to claim 1.

(Wherein R ₁ represents a hydrogen atom or a substituent, R _{2 to} R ₆ represent a substituent, and R ₂ and R ₃ , R ₅ and R ₆ are bonded to each other to form a 5- or 6-membered ring. Represents an atomic group, and X and Y represent an oxygen atom, a sulfur atom, or a nitrogen atom.)
(Claim 3)
The photothermographic image-forming material according to claim 1 or 2, comprising at least one compound selected from a phthalazine compound, a polyhalomethane compound, and a bisphenol compound.

(Claim 4)
The photothermographic image-forming material according to any one of claims 1 to 3, wherein the phthalazine compound is a compound represented by the following general formula (2).

(Wherein R ^{2 to} R ^{7 each} represent a halogen atom, a cyano group, a hydroxyl group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aromatic group, or a heterocyclic group, each of which may have a substituent. .)
(Claim 5)
The photothermographic image forming material according to any one of claims 1 to 4, wherein the polyhalomethane compound is a compound represented by the following general formula (3).

Wherein X ¹ , X ² and X ³ represent a hydrogen atom, a halogen atom, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a sulfonyl group or an aryl group, at least one of which is a halogen atom. ₁ represents —C (═O) —, —SO— or —SO ₂ —, and p represents 0 or 1. Z ₂ is a cyclic substituent.
(Claim 6)
The bisphenol compound is a compound represented by the following general formula (4) a and general formula (4) b, and at least two of these compounds are used in combination, and the compound represented by the general formula (4) b is represented by the general formula (4) The photothermographic image-forming material according to any one of claims 1 to 5, wherein the photothermographic image material is contained in a mole number of 1/2 to 1/1000 moles per mole of the compound represented by a.

(In the formula, R represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aromatic ring group or a heterocyclic group, and R _{a1 to} R _a4 and R _{b1 to} R _b4 have 1 to 5 carbon atoms. Represents a linear or branched alkyl group.)
(Claim 7)
The crosslinking agent for crosslinking the binder of the photosensitive layer or a layer adjacent to the photosensitive layer is at least one compound selected from an isocyanate compound and a vinyl sulfone compound. The photothermographic image-forming material according to Item.

As a result of intensive studies, the present inventor has found that the benzimidazolyl group, the benzthiazolyl group, or the benzoxazolyl group having the R ₁ O— group (R ₁ is a hydrogen atom or a substituent) as a substituent, a thiazole compound. Alternatively, the photothermographic image-forming material contains an oxazole compound to improve photographic performance (sensitivity and fog characteristics), raw storage and image storage during development, and further protect the hydroxyl group or hydroxyl group of the present invention. A benzimidazolyl group having a group, a benzthiazolyl group or an imidazole compound having a benzoxazolyl group as a substituent, a thiazole compound or an oxazole compound and at least one compound selected from phthalazine, polyhalomethane, and a bisphenol compound, Or isocyanato and Found that improving during thermal development photographic performance and storage stability and image storage stability by crosslinking at least one crosslinking agent in addition a binder selected from vinyl sulfonyl crosslinking agent

  The photothermographic image forming material according to the present invention has high sensitivity and low fog, and has excellent effects on storage stability before development (abbreviated as raw storage) and storage stability after development (abbreviated as image storage). .

  Next, the best mode for carrying out the present invention will be described, but the present invention is not limited thereto.

  Hereinafter, the present invention will be described in detail.

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. BC layer, its protective layer and the like. 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. A benzimidazolyl group, a benzthiazolyl group, or a benzoxa that contains a reducing agent for developing a salt, a silver salt to form a silver image, and having the R ₁ O— group (R ₁ is a hydrogen atom or a substituent) of the present invention An imidazole compound, thiazole compound or oxazole compound having a zolyl group as a substituent 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, an AI layer or a BC layer containing a dye for preventing irradiation or preventing halation is provided if necessary.

Hereinafter, an imidazole compound having a benzimidazolyl group, a benzthiazolyl group, or a benzoxazolyl group having a R ₁ O— group (R ₁ is a hydrogen atom or a substituent) contained in the photothermographic image forming material of the present invention as a substituent. The compound represented by the general formula (1), the phthalazine compound, the polyhalomethane compound, the reducing agent, and the crosslinking agent, which are preferable compounds of the thiazole compound or the oxazole compound, 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.

In the general formula (1), R ₁ represents a hydrogen atom or a substituent, and the substituent represents an alkyl group (for example, a methyl group, an ethyl group, or a t-butyl group). R _{2 to} R ₆ are each a hydrogen atom, a halogen atom (chlorine atom or bromine atom), a linear, branched or cyclic alkyl group (methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group). Group, t-butyl group, n-hexyl group, n-octyl group, iso-octyl group, n-dodecyl group, adamantyl group, cyclohexyl group, cyclobutyl group, etc.) aryl group (phenyl group, naphthyl group, pyridyl group, quinolyl) Group, imidazolyl group, thiazolyl group, thiadiazolyl group, etc.), acyl group, alkoxycarbonyl group, aryloxycarbonyl group, cyano group, carboxyl group, alkoxy group (methoxy group, ethoxy group, butoxy group, octoxy group, dodecyloxy group, etc.) ), Aryloxy group (phenoxy group, naphthoxy group, etc.), acyloxy group, acyl Amino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfonylamino group, a carbamoyl group, a mercapto group, an alkylthio group (methylthio group, ethylthio group, etc.) a group selected from, R ₂ and R _3, R ₅ and R ₆ may be bonded to each other to form a 5- or 6-membered ring, and X and Y are groups containing a nitrogen atom (> NH group,> N—R group (R is an alkyl group such as> N— _{CH 3,> N-C 2} H 5 , etc.)), a sulfur atom or an oxygen atom. A method for synthesizing these compounds can be synthesized with reference to JP-A-2002-080476.

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. Alternatively, fine particles may be dispersed and added. 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. .

  Specific examples of the compound represented by the general formula (1) that are preferably 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.
The compound represented by the general formula (2), which is a phthalazine compound preferably used in the present invention, will be described.

In the general formula (2), the substituents R ^{2 to} R ⁷ are each a halogen atom, a cyano group, a hydroxy group, an alkyl group that may have a substituent, an alkenyl group, an alkynyl group, an alkoxy group, an aromatic group, Represents a heterocyclic group. The function of the substituent may be a group such as a group that controls diffusibility, a non-diffusible group, a diffusible group, an adsorptive 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, good effects cannot be obtained in terms of fog suppression, color tone and storage stability. These substituents may be the same as the substituents 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.

  The polyhalomethane compound preferably used in the present invention is a compound having at least one trihalomethane group in one molecule, and is substituted on an aliphatic group or substituted with an aromatic ring or a heterocyclic ring. The aromatic ring or hetero ring may be further connected to the aromatic ring or hetero ring via a divalent linking group. The aromatic group is preferably a phenyl group or a naphthalene group, and a rogen atom such as a chlorine atom, a bromine atom, a fluorine atom or an alkyl group such as a methyl group, an ethyl group, a butyl group, an octyl group, a dodecyl group or an octadecyl group on these rings. Examples of the heterocyclic group include a pyridine group, a pyrimidine group, a quinoline group, a furan ring group, a thiophene ring group, an imidazole group, a triazole group, an oxazole group, a thiazole group, a thiadiazole group, and an oxadiazole group. On the ring, you may have a substituent similar to an aromatic ring. In addition, a group for imparting diffusion resistance or a group that promotes adsorption to silver halide may be substituted on the aromatic ring or the hetero ring. The group adjacent to the trihalomethane group is preferably a sulfonyl group or a carbonyl group, but may be directly bonded to an aromatic ring or a hetero ring, and the bonding method is not limited. Aromatic rings and hetero rings are reduced, and non-aryl saturated rings are particularly preferred. The halogen atom of the trihalomethane group is preferably a bromine atom, but may be chlorine, fluorine, iodine, or a combination thereof. A preferred compound is a compound represented by the general formula (3).

In the general formula (3), X ¹ , X ² and X ³ represent a hydrogen atom, a halogen atom, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a sulfonyl group or an aryl group, but at least one is a halogen atom is there. L ₁ represents —C (═O) —, —SO— or —SO ₂ —, and p represents 0 or 1.

The ring represented by Z ₂ may be a saturated or unsaturated monocyclic or condensed ring, and is preferably a monocyclic or bicyclic group having 6 to 30 carbon atoms (for example, phenyl, naphthyl, etc.), The heterocyclic ring represented by Z ₂ 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, and more preferably a 5- to 6-membered aromatic group which may have a condensed ring. It is a heterocyclic group. More preferably, it is a 5- or 6-membered saturated or unsaturated heterocyclic group optionally having a condensed ring containing a nitrogen atom, and particularly preferably a condensed ring containing 1 to 4 nitrogen atoms. A good 5- to 6-membered unsaturated heterocyclic group.

  Heterocycles in such heterocyclic groups include imidazole, pyrazole, pyridine, pyrimidine, pyrazine, pyridazine, triazole, triazine, indole, phospholene, purine, thiadiazole, oxadiazole, quinoline, phthalazine, naphthyridine, quinoxaline, quinazoline , Pteridine, acridine, phenazine, tetrazole, thiazole, oxazole, benzimidazole, benzoxazole, benzthiazole, indolenine, tetrazaindene and the like, more preferably imidazole, pyridine, pyrimidine, pyrazine, pyridazine, triazole , Triazine, thiadiazole, oxadiazole, quinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, tetrazole, thiazo Oxazole, benzimidazole, benzoxazole, benzthiazole, tetrazaindene, more preferably imidazole, pyridine, pyrimidine, pyrazine, pyridazine, triazole, triazine, thiadiazole, quinoline, phthalazine, naphthyridine, quinoxaline, quinazoline , Cinnoline, tetrazole, thiazole, benzimidazole, and benzthiazole, particularly preferably piperidine, piperazine, pyridine, thiadiazole, quinoline, and benzthiazole.

The ring group represented by Z ₂ may have a substituent in addition to —L ₁ —C (X ¹ ), (X ² ), and (X ³ ), and the substituent is preferably an alkyl group or alkenyl. Group, aryl group, alkoxy group, aryloxy group, acyloxy group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group , Sulfonyl group, ureido group, phosphoric acid amide group, halogen atom, cyano group, sulfo group, carboxyl group, nitro group, heterocyclic group, more preferably alkyl group, aryl group, alkoxy group, aryloxy group, acyl Group, acylamino group, alkoxycarbonylamino group, aryloxycarbonyl group Group, sulfonylamino group, sulfamoyl group, carbamoyl group, ureido group, phosphoric acid amide group, halogen atom, cyano group, nitro group, heterocyclic group, more preferably alkyl group, aryl group, alkoxy group, aryloxy Group, acyl group, acylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group, halogen atom, cyano group, nitro group and heterocyclic group, particularly preferably alkyl group, aryl group and halogen atom. X ¹ , X ² and X ³ are preferably a halogen atom, a haloalkyl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a sulfamoyl group, a sulfonyl group or a heterocyclic group, more preferably a halogen atom, A haloalkyl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, and a sulfonyl group, more preferably a halogen atom and a trihalomethyl group, and particularly preferably a halogen atom. Of the halogen atoms, preferred are a chlorine atom, a bromine atom and an iodine atom, more preferred are a chlorine atom and a bromine atom, and particularly preferred is a bromine atom.

  Specific examples of these compounds are listed below.

  Examples of the bisphenols of the present invention include bis (2-hydroxy-3-t-butyl-5-methylphenyl) methane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, and ultraviolet-sensitive ascorbine. Examples thereof include acid derivatives and 3-pyrazolidones. Of these, particularly preferred reducing agents are bisphenols.

  Bisphenols are more preferable than the compounds represented by general formula (4) a and general formula (4) b.

In Formula (4) a and formula (4) b, R is a hydrogen atom, or a carbon atom number of 1 to 10 alkyl group (e.g., -C ₄ H _9, 2,4,4-trimethyl pentyl), Represents an aromatic ring group (for example, phenyl group, naphthyl group, cyclopentadienyl group, cyclohexenyl group, etc.) or heterocyclic group (furyl group, thiophenyl group, pyridyl group, oxazolyl group, thiazolyl group, etc.), R _a1 to R _a4 and R _b1 to R _b4 represents a linear or branched alkyl group having 1 to 5 carbon atoms (e.g., methyl, ethyl, t- butyl, etc.).
Specific examples of the compounds represented by general formula (4) a and general formula (4) b are shown below, but the present invention is not limited to the following compounds.

As a method of using the bisphenols, a phenol group is bonded with a methylene group in the photosensitive layer or a layer adjacent to the photosensitive layer, and the bonding group is in an ortho position (a type) and a para position with respect to the hydroxyl group. It is preferable to use such that at least one bisphenol compound (b-type) is contained. 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. . When two or more types are used, it is preferable to always include the a-type and the b-type, and the total amount used may be within the above range. The b-type is preferably from 1/2 to 1/1000, particularly preferably from 1/10 to 1/100, as compared to the a-type.

Phthalazine compound used in combination with imidazole compound, thiazole compound or oxazole compound having benzimidazolyl group, benzthiazolyl group or benzoxazolyl group having R ₁ O-group (R ₁ is hydrogen atom or substituent) of the present invention as a substituent The polyhalomethane compound, the bisphenol compound, the crosslinking agent and the like are preferably added in an amount of 1 × 10 ⁻² mol to 1 × 10 ³ mol with respect to 1 mol of the compound represented by the general formula (1) of the present invention. 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).

  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, and organic acids, heteroorganic acids and acid polymer silver salts containing a reducible silver ion source are 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: salts of organic acids (eg, gallic acid, oxalic acid, behenic acid, arachidic acid, stearic acid, palmitic acid, lauric acid) Salts of acids and the like).

(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 compounds described in Research Disclosure Nos. 17029 and 29963 can also be used.

(Photosensitive silver halide grains)
The photosensitive silver halide 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, for example, an ammonia emulsion or neutral emulsion. It can be prepared in advance by any method such as a 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 contact the photosensitive silver halide and the organic silver salt, for example, U.S. Pat. Nos. 3,706,564 and 3,706 are used as protective polymers when preparing the photosensitive silver halide. , 565, 3,713,833, 3,748,143, British Patent 1,362,970, etc., and means using a polymer other than gelatin such as polyvinyl acetals Or means for enzymatic degradation of gelatin in light sensitive silver halide emulsions as described in British Patent 1,354,186, or as described in US Pat. No. 4,076,539. Thus, each means such as a 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 preferably has a small grain size in order to keep 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 silver halide is not particularly limited, and examples thereof include cubic and octahedral so-called normal crystals and 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 silver halide 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 silver halide and the organic silver salt described later. 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 silver halide forming component can be appropriately set according to the purpose of preparation. 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 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. . 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 order to achieve sensitization, as described in US Pat. No. 3,980,482, when a part of the organic silver salt is converted to photosensitive silver halide by the silver halide forming component. In addition, an amide compound having a low molecular weight may coexist.

  Further, these photosensitive silver halides include illuminance failure and metals belonging to Groups 6 to 10 of the Periodic Table of Elements, such as Rh, Ru, Re, Ir, Os, Fe, etc. for gradation adjustment. Ions, their complexes or complex ions can be included. 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 simultaneous mixing of three liquids, a method of introducing an aqueous solution of a required amount of a metal compound into a 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 particle surface, a necessary amount of an aqueous solution of a metal compound can be charged into the reaction vessel immediately after the formation of the particle, during or after the physical ripening, or at the 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, compounds described in JP-A Nos. 9-34078, 9-54409, and 9-80679 are preferably used.

(binder)
The polymer binder used in the photosensitive layer or the non-photosensitive layer of the photothermographic image-forming material of the present invention is preferably a material that is preferable for the reaction of silver halide, organic silver salt, and reducing agent, and a thermodecolorable dye of 80 to 200. A material that is preferable for a reaction that is decolorized by heat at a temperature of 0 ° C. or lower, or a material that allows the base-generating precursor to rapidly generate 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 used by dissolving 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, sodium polyacrylate, poly Ethylene oxide, acrylic acid amide-acrylic acid ester copolymer, styrene-maleic anhydride copolymer, polyacrylamide, sodium alginate, gelatin, casein, polystyrene, polyvinyl acetate, polyurethane, polyacrylic acid, polyacrylic acid ester, styrene -Butadiene copolymer, acrylonitrile-butadiene copolymer, vinyl chloride-vinyl acetate copolymer, styrene-butadiene-a Such as Lil 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 the binder alone, it is possible to maintain adhesion to the lower layer and the upper layer and to obtain a film strength that is difficult to get scratched. However, in the present invention, by using a cross-linking agent, film adhesion and film can be further increased. Strength can be increased. The crosslinking agent can be used by being added to the method of adding to the undercoat layer, AH 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.

  The preferred crosslinking agent is preferably at least one compound (crosslinking agent) selected from crosslinking agents having an isocyanate group and a vinylsulfonyl group. Particularly preferred crosslinking agents include polyfunctional crosslinking agents having at least 2, more preferably 3, isocyanate groups or vinylsulfonyl groups. JP, 2003-002874, A can refer to the synthesis method of a vinyl sulfonyl compound. H1-H13 are shown below as specific examples of preferable crosslinking agents in the present invention.

(H1) Hexamethylene diisocyanate (H2) Trimer of hexamethylene diisocyanate (H3) Tolylene diisocyanate (H4) Phenylene diisocyanate (H5) Xylylene diisocyanate

(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 concretely, the aspect of this invention is not limited by these.

[Examples of Photothermographic Image Forming Material (1)]
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.

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

(Undercoating liquid b-1)
270 g of copolymer latex liquid (solid content 30%) of butyl acrylate (40 mass%), styrene (20 mass%), glycidyl acrylate (40 mass%)
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.

(Undercoat upper layer coating solution 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 (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. Next, halogenation (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.

(Application of photosensitive layer and BC layer)
The following layers were sequentially formed on the support provided with the undercoat layer to prepare a sample. In addition, each drying was performed for 1 minute at 45 degreeC.

(BC layer side coating)
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 coating)
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: PBV-1 0.4 g / m ²
Dye: C (same type as BC layer) 0.02 g / 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. An amount of the preparation solution that would be 1.26 g / m ² as silver amount was mixed with the polymer binder.

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
As a comparative compound, No. 1 in Table 3 in Examples of JP-A-2003-75952. Thirteen 4-41 compounds were used as comparative compound VB-0.

Compound represented by the general formula (2): listed in Table 1 2.2 × 10 ⁻⁴ mol / m ²
Compound 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 agents represented by general formula (4) a and general formula (4) b:
Table 1 3.3 mmol / m ²
As the reducing agent (BP-0), 2,6-di-t-butyl-4-methylphenol was used.

When the compounds of general formula (4) a and general formula (4) b are used in combination, BP-O (ortho BP) is 3 mmol / m ² and p (para) -BP is 0.3 mmol / m ^2. used.

Cross-linking agent: 2 × 10 ⁻⁵ mol / m ² (described in Table 1)
In addition, phenylaminoethoxytrimethoxysilane (H-0) was also used as a 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 pieces of the above-prepared sample with a size of 5 cm × 12 cm, it was divided into two, and one was exposed with a 810 nm semiconductor laser exposure photometer in an atmosphere of 46% RH at 23 ° C., and after exposure 127 After heating at 0 ° C. for 8 seconds, the photographic performance of the obtained sample was evaluated (sample at room temperature). The other is 23 ° C RH46%, sealed in a confidential aluminum foil packaging bag under reduced pressure (10 hPa), stored in a constant temperature room at 40 ° C for 30 days (high temperature sample), and then exposed and developed in the same manner. The obtained sample was used as a raw preservation test sample. 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%.

  The sensitivity and fog of the room temperature sample and the high temperature sample were measured with a densitometer. The sensitivity was evaluated by the reciprocal of the ratio of the exposure amount giving a density 0.3 higher than the fog density, and expressed by relative evaluation with the sample 101 as a reference (100). The storage stability after image development (image storage stability) is a light fog value after a developed sample is left on a shaucusten having a luminance of 10,000 lux for 10 hours.

  From Table 1, it can be seen that when the compound of the present invention is used, the photographic performance (sensitivity and fog characteristics), raw storability and image storability during development are excellent. The compound of the present invention (preferably the compound represented by the general formula (1)) and phthalazine, polyhalomethane and bisphenol compound are used in combination, or the binder is further crosslinked with at least one compound selected from isocyanate and vinylsulfonyl crosslinking agent. Then, it can be seen that the photographic performance (sensitivity, fog, raw storability and image storability) during heat development is improved.

Claims (7)

In a photothermographic image-forming material having a photosensitive layer containing photosensitive silver halide grains, organic silver salt, reducing agent and binder on a support, a benzimidazolyl group, a benzthiazolyl group or a benzoxa group having an R ₁ O-group A photothermographic image-forming material comprising an imidazole compound, thiazole compound or oxazole compound having a zolyl group as a substituent.
R ₁ represents a hydrogen atom or a substituent. The imidazole compound, thiazole compound or oxazole compound having the benzimidazolyl group, benzthiazolyl group or benzoxazolyl group having the R ₁ O— group as a substituent is a compound represented by the following general formula (1): The photothermographic image-forming material according to claim 1.

(Wherein R ₁ represents a hydrogen atom or a substituent, R _{2 to} R ₆ represent a substituent, and R ₂ and R ₃ , R ₅ and R ₆ are bonded to each other to form a 5- or 6-membered ring. Represents an atomic group, and X and Y represent an oxygen atom, a sulfur atom, or a nitrogen atom.) The photothermographic image-forming material according to claim 1 or 2, comprising at least one compound selected from a phthalazine compound, a polyhalomethane compound, and a bisphenol compound. The photothermographic image-forming material according to any one of claims 1 to 3, wherein the phthalazine compound is a compound represented by the following general formula (2).

(Wherein R ^{2 to} R ^{7 each} represent a halogen atom, a cyano group, a hydroxyl group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aromatic group, or a heterocyclic group, each of which may have a substituent. .) The photothermographic image forming material according to any one of claims 1 to 4, wherein the polyhalomethane compound is a compound represented by the following general formula (3).

Wherein X ¹ , X ² and X ³ represent a hydrogen atom, a halogen atom, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a sulfonyl group or an aryl group, at least one of which is a halogen atom. ₁ represents —C (═O) —, —SO— or —SO ₂ —, and p represents 0 or 1. Z ₂ is a cyclic substituent. The bisphenol compound is a compound represented by the following general formula (4) a and general formula (4) b, and at least two of these compounds are used in combination, and the compound represented by the general formula (4) b is represented by the general formula (4) The photothermographic image-forming material according to any one of claims 1 to 5, wherein the photothermographic image material is contained in a mole number of 1/2 to 1/1000 moles per mole of the compound represented by a.

(In the formula, R represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aromatic ring group or a heterocyclic group, and R _{a1 to} R _a4 and R _{b1 to} R _b4 have 1 to 5 carbon atoms. Represents a linear or branched alkyl group.) The crosslinking agent that crosslinks the binder of the photosensitive layer or a layer adjacent to the photosensitive layer is at least one compound selected from an isocyanate compound and a vinylsulfone compound. The photothermographic image-forming material according to Item.