JP2003021884A - Photothermographic image forming material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photothermographic image forming material which ensures high sensitivity and low fog, suppresses fog due to print-out silver after development, is excellent in raw stock preservability before development and in image preservability after development and has little residual color and a stable color tone after development. SOLUTION: In the photothermographic image forming material having a photosensitive layer containing photosensitive silver halide grains, an organic silver salt, a reducer and a binder on a support, a phosphorene compound is contained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photothermographic image forming material which forms an image by thermal development, and more particularly to a photothermographic image forming material which can obtain high sensitivity and low fog and has excellent storage stability. Further, the present invention relates to a photothermographic image forming material which has excellent storability of an image obtained after development and suppresses printout silver.

[0002]

2. Description of the Related Art In recent years, a photothermographic material that does not produce waste liquid associated with a wet process has been strongly desired in the fields of medical treatment and printing from the viewpoint of environmental protection and workability. There is a need in the art for photothermographic materials for photographic applications that are capable of forming images. Since these photothermographic materials are usually developed at a temperature of 80 ° C. or higher, they are called photothermographic image forming materials.

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

Generally, a photothermographic image forming material is easy to process because it produces an image only by heat development after exposure, but since there is no fixing step, it is important to improve the storability of the image after development. . To improve the storability after development,
It is preferable to develop the image at a high temperature so that an image can be obtained, but if the temperature is too high, fog is likely to occur and the sensitivity is lowered. Therefore, development is generally performed at a temperature of 120 ° C. ± 10 ° C. The use of mercapto compounds to reduce fog is disclosed in JP-A-63-301037,
It is disclosed in JP-A-5-341432, JP-A-5-509182, and JP-A-2000-19681. But,
In either case, the mercapto compound is less effective in suppressing fog, and it is difficult to obtain high sensitivity, and there is a limit in improving storage stability. The use of a phthalazine compound for suppressing printed silver is disclosed in JP-A Nos. 50-67132 and 61-18.
3642, JP-A-9-114036 and 9-258.
366, 10-508599, 10-33993.
No. 1, No. 11-49756, No. 11-218877.
No. 11-223900, JP 2000-1023.
No. 4, 2000-10232 and 2000-3.
No. 5630 is disclosed. By using both phthalazine or additives other than phthalazine,
Although it is described that the fog, the sensitivity density, the storability and the like are improved, the use of the phosphorene compound and the effect when used in combination with the compound are not described. A polyhalomethane compound is effective for suppressing bake-out silver after development, and it is effective to use a polyhalomethane compound in JP-A 9-244177 and 9-26.
No. 5150 and No. 9-319022 improve the effects of raw storability, image storability, color tone, and suppression of print-out silver by specifying the structure, but they are not sufficient.

In order to improve the storage stability, the crosslinking of the binder is adjusted to pH.
Attempts have been made to improve the properties by using a crosslinking agent or a crosslinking agent, but this is not sufficient.

[0006]

SUMMARY OF THE INVENTION It is a first object of the present invention to provide a photothermographic image forming material excellent in high sensitivity and low fog in photographic performance. A second object of the present invention is to provide a photothermographic image forming material in which fogging due to printed silver after development is suppressed. A third object of the present invention is to provide a photothermographic image forming material which is excellent in raw storability before development and image storability after development, has little residual color after development, and has stable color tone. It is in.

[0007]

The above objects of the present invention have been achieved by the following constitutions.

1. Photosensitive silver halide grains on a support,
A photothermographic image forming material having a photosensitive layer containing an organic silver salt, a reducing agent and a binder, wherein the photothermographic image forming material contains a phosphorene compound.

2. 1 wherein the phosphorene compound is a compound represented by the general formula (1)
The photothermographic image forming material described in 1.

3. 3. The photothermographic image forming material as described in 1 or 2 above, which contains a phthalazine compound in a photosensitive layer of the photothermographic image forming material or a layer adjacent to the photosensitive layer.

4. 4. The photothermographic image forming material described in any one of 1 to 3 above, wherein the photosensitive layer or a layer adjacent to the photosensitive layer contains a polyhalomethane compound.

5. 5. The photothermographic image forming material described in any one of 1 to 4 above, which contains a bisphenol compound in the photosensitive layer or a layer adjacent to the photosensitive layer.

6. Any of the above 1 to 5, wherein the crosslinking agent for crosslinking the binder of the photosensitive layer or a layer adjacent to the photosensitive layer is at least one selected from an isocyanate compound, a vinyl sulfone compound and an epoxy compound. The photothermographic image-forming material as described in 1 above.

The present invention will be described in more detail. The photothermographic imaging element of this invention will normally have at least 1 part on a support.
A BC layer provided on the opposite side of the photosensitive layer, a protective layer thereof, and the like, which are composed of at least two layers having a photosensitive layer and a layer adjacent to the photosensitive layer. The photosensitive layer of the photothermographic image-forming material contains photosensitive silver halide grains which may be sensitized with a spectral sensitizing dye, and the photosensitive layer or its adjacent layer further contains organic silver as a silver source. A reducing agent for developing a salt or a silver salt to form a silver image is contained, and the phosphorene compound of the present invention is contained.

The photosensitive layer of the photothermographic image-forming material or a layer adjacent to the photosensitive layer contains a polymer binder, a hydrophilic binder or a hydrophobic binder which provides a field for a heat development reaction, and more preferably. Contains an isocyanate compound, a vinyl sulfone compound, an epoxy compound or the like which crosslinks and cures the binder. In the above photothermographic image forming material, an AI layer or a BC layer containing a dye for preventing irradiation or for preventing halation is provided if necessary.

The phosphorene compound, the phthalazine compound and the polyhalomethane compound contained in the photothermographic image-forming material of the present invention will be described below 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, and the high-concentration contained in the photosensitive layer or its adjacent layer. The molecular binder and the like will be described later in sequence.

(Phosphorene Compound) The phosphorene compound of the present invention will be described. A phosphorene compound is a compound having at least one phosphorus atom and having a 5-membered phosphorene ring containing a phosphorus atom in the mother nucleus, and photofunctional image formation by introducing various functional groups into the phosphorene ring. The properties of the material can be improved. In the phosphorene ring,
Substituents that improve photographic characteristics and storability can also be introduced.

In the general formula (1), the alkyl group, alkenyl group and alkynyl group represented by R ¹ each preferably have 1 to 20 carbon atoms which may be substituted, and examples thereof include a methyl group, an ethyl group and a butyl group. , Octyl group, dodecyl group, trifluorobutyl group, pentafluoropropyl group, acetyl group, butenyl group, nonenyl group and the like, aromatic groups include, for example, phenyl group, p-hydroxyphenyl group,
p-aminophenyl group, p-glycidylphenyl group, p
-Methylphenyl group, p-methoxyphenyl group, p-cyanophenyl group, naphthyl group, 1,5-dimethylnaphthyl group, 2,6-dimethylnaphthyl group, etc.
Alkoxy groups such as pyridyl group, furyl group, imidazole group, triazole group, thiazole group and the like include, for example, methoxy group, ethoxy group, butoxy group, octoxy group, butenooxy group, phenoxy group, p-aminophenoxy group, p
-Glycidylphenoxy group, p-butylisocyanatophenoxy group, p-trimethoxysilanopropyloxyphenoxy group, pyridineoxy group, thiophenyloxy group, substituted amino group are, for example, phenylamino group, p-
Examples thereof include a thiadiazole amino group, a trioxysilanopropylamino group, a p-trimethoxypropyloxyphenoxyamino group and the like. The halogen atom is preferably chlorine or bromine, and the alkyl group or alkenyl group may contain straight chain, branched chain, saturated or unsaturated.

Specific examples of preferable phosphorene compounds are shown below, but the invention is not limited thereto.

[0020]

[Chemical 2]

[0021]

[Chemical 3]

[0022]

[Chemical 4]

[0023]

[Chemical 5]

[0024]

[Chemical 6]

The above-mentioned phosphorene compound of the present invention can be synthesized by referring to the methods described in US Pat. Nos. 2,663,737, 2,663,739 and 2,663,736.

These synthesized phosphorene compounds can be added according to a known addition method. For example, it is preferable to add it after dissolving it in alcohols such as methanol and ethanol, ketones such as methyl ethyl ketone and acetone, polar solvents such as dimethyl sulfoxide and dimethylformamide, and the like. In addition, 1 by sand mill dispersion, jet mill dispersion, ultrasonic dispersion or homogenizer dispersion
It is also possible to make fine particles of μm or less and disperse them in water or an organic solvent before adding. The addition amount is preferably in the range of 1/1000 to 60% by mass in the coating liquid,
The range of 1/100% by mass to 30% by mass is particularly preferable, and the addition amount can be appropriately adjusted and used in this range. When it is added in the number of moles, it is preferably added at 10 ⁻⁶ mol to 10 ⁻² mol / m ² .

(Phthalazine Compound) The phthalazine compound can be obtained by introducing various substituents into the phthalazine ring. A preferable phthalazine compound can be represented by the following general formula (2).

[0028]

[Chemical 7]

In the formula, the substituents R ^{2 to} R ⁷ are halogen atoms,
A cyano group, a hydroxy group, an alkyl group which may have a substituent, an alkenyl group, an akinyl group, an alkoxy group, an aromatic group and a heterocyclic group, which may each have a substituent. It may be a group that controls the diffusibility as a function of the substituent, a non-diffusible group, a diffusible group, an adsorptive group, an acidic group, or the like. The number of carbon atoms of the alkyl group, alkenyl group, alkynyl group, and alkoxy group is 1 to
60 is preferable, and 1 to 40 is particularly preferable. When the number of carbon atoms is large, good effects in fog control, color tone and storability cannot be obtained. These substituents may be the same as the substituents on the phosphorene ring. Specific examples of preferable phthalazine compounds are shown below.

[0030]

[Chemical 8]

(Polyhalomethane Compound) The polyhalomethane compound used in the present invention is a compound having at least one trihalomethane group in one molecule, and is substituted on an aliphatic group, an aromatic ring or a heterocycle. Has been replaced by. The aromatic ring or hetero ring may be further linked to the aromatic ring or hetero ring via a divalent linking group. The aromatic is preferably a phenyl group or a naphthalene group, and a rogen atom on these rings, for example, a chlorine atom, a bromine atom, a fluorine atom, an alkyl group, for example, a methyl group, an ethyl group, a butyl group, an octyl group, a dodecyl group, octadecyl. Examples of the heterocyclic group such as a 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. In the ring,
It may have the same substituents as the aromatic ring. In addition, a group for imparting diffusion resistance or a group for promoting adsorption to silver halide may be substituted on the aromatic ring or hetero ring. The group adjacent to the trihalomethane group is preferably a sulfonyl group or a carbonyl group, but may be directly bonded to the aromatic ring or the hetero ring, and the bonding method is not limited. A non-aryl type saturated ring in which an aromatic ring or a hetero ring is reduced is particularly preferable. The halogen atom of the trihalomethane group is preferably a bromine atom, but may be chlorine, fluorine, iodine, or a combination thereof. A preferred structure is shown in the following general formula (3).

[0032]

[Chemical 9]

In the formula, Z ₂ represents a ring group, and X ¹ , X ² and X ³
Is a hydrogen atom, 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,
Haloalkyl group, acyl group, alkoxycarbonyl group,
Represents an aryloxycarbonyl group or a sulfonyl group,
At least one is a halogen atom. L ₁ represents a divalent linking group, and p represents 0 or 1.

The ring group represented by Z ₂ may be a saturated or unsaturated monocyclic ring or a condensed ring, and preferably has 6 carbon atoms.
~ 30 monocyclic or bicyclic groups (eg adamantyl group,
Cyclobutane group, cyclopropane group, cyclopentane group, cyclooctane group, cyclobutene group, cyclopentene group, cyclohexene group, phenyl, naphthyl, etc.), and more preferably adamantyl group, cyclopentane group, cyclohexane group, cyclohexene group, cyclohexanone group. , A cyclopentene group, a phenyl group and a naphthyl group, and more preferably a phenyl group. The heterocycle 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 a monocycle, It may form a condensed ring with another ring. 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- or 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 which may have a condensed ring containing a nitrogen atom, and particularly preferably, it may have a condensed ring containing 1 to 4 nitrogen atoms. It is a good 5- to 6-membered unsaturated heterocyclic group. Examples of the heterocycle in such a heterocyclic group include imidazole, pyrazole, pyridine, pyrimidine, pyrazine, pyridazine, triazole, triazine, indole, phosphorene, purine, thiadiazole, oxadiazole, quinoline, phthalazine, naphthyridine, quinoxaline, 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, quinazoline, cinnoline, tetrazole, thiazole, 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 are preferable, and pyridine, triazine, thiadiazole, quinoline and benzthiazole are particularly preferable.

The ring group represented by Z ₂ is-(L ₁ ) _p -C
It may have a substituent in addition to (X ¹ ), (X ² ), and (X ³ ), and the substituent is preferably an alkyl group, an alkenyl group, an aryl group, an alkoxy group, an aryloxy group,
Acyloxy group, acyl group, alkoxycarbonyl group,
Aryloxycarbonyl group, acyloxy 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 Group, a carboxyl group, a nitro group, a heterocyclic group, more preferably an alkyl group, an aryl group, an alkoxy group,
Aryloxy group, acyl group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group, ureido group, phosphoramide group, halogen atom, cyano group, nitro group, heterocycle More preferably, it is an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an acyl group, an acylamino group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, a halogen atom, a cyano group, a nitro group or a heterocyclic group. , Particularly preferably an alkyl group, an aryl group, or a 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, and more preferably A halogen atom, a haloalkyl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group and a sulfonyl group are more preferable, a halogen atom and a trihalomethyl group are more preferable, and a halogen atom is particularly preferable. Among the halogen atoms, chlorine atom, bromine atom and iodine atom are preferable, chlorine atom and bromine atom are more preferable, and bromine atom is particularly preferable.

L ₁ is -O-, -S-, -C (= O)-,
_{-SO -, - SO 2 -,} - CH 2 = CH 2 -, - CF 2 = C
It represents F ₂ —, preferably —SO ₂ —.

Specific examples of these compounds are shown below.

[0039]

[Chemical 10]

[0040]

[Chemical 11]

[0041]

[Chemical 12]

The addition amount can be in the range of 10 ^-6 mol to 10 ^-2 mol per silver halide. The position of addition is not limited to the photosensitive layer in which silver halide is present, and may be an adjacent layer or an undercoat layer. The method of addition can be the same as that of the phosphorene compound.

Next, the organic silver salt, reducing agent, photosensitive silver halide grain, binder, crosslinking agent, dye, matting agent and other support used in the photothermographic image forming material of the present invention will be explained 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 contains an organic acid, a heteroorganic acid and an acid polymer containing a reducible silver ion source. The silver salt and the like are used. Also, the ligand is
Organic or inorganic silver salt complexes having a total stability constant for silver ions of 4.0 to 10.0 are also useful. An example of silver salt is
Research Disclosure 17029
And 29963 and include the following: salts of organic acids such as gallic acid, oxalic acid, behenic acid, stearic acid, palmitic acid, lauric acid, and the like.

(Reducing Agent) Examples of preferable reducing agents contained in the photothermographic image forming material of the present invention are described in US Pat.
70,448, 3,773,512, 3,59
No. 3,863, etc., and Research D
isclosure 17029 and 29963, which include:

Bisphenols (for example, bis (2-hydroxy-3-t-butyl-5-methylphenyl) methane, bis (6-hydroxy-m-tri) mesitol (m
esitol), 2,2-bis (4-hydroxy-3-)
Methylphenyl) propane), UV-sensitive ascorbic acid derivative; hindered phenols; 3-pyrazolidones. Among them, particularly preferable reducing agents are hindered phenols. Examples of the hindered phenols include compounds represented by the following general formula (4).

[0047]

[Chemical 13]

In the formula, R is a hydrogen atom or 1 to 1 carbon atoms.
10 represents an alkyl group (eg, —C ₄ H ₉ , 2,4,4-trimethylpentyl), and R ′ and R ″ are alkyl groups having 1 to 5 carbon atoms (eg, methyl, ethyl, t-butyl). ) Represents.

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.

[0050]

[Chemical 14]

[0051]

[Chemical 15]

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

(Photosensitive Silver Halide Grain) The photosensitive silver halide contained in the photosensitive layer of the photothermographic image-forming material of the present invention can be any of those known in the photographic art such as a single jet method or a double jet method. Can be prepared in advance by any method such as an ammonia method emulsion, a neutral method, an acidic method, etc., and then mixed with other components of the present invention and introduced into the composition used in the present invention. . In this case, in order to sufficiently bring the photosensitive silver halide and the organic silver salt into contact with each other, for example, as a protective polymer in preparing the photosensitive silver halide, US Pat. No. 3,706,564,
No. 3,706,565, No. 3,713,833
No. 3,748,143, British Patent No. 1,36
Means for using polymers other than gelatin such as polyvinyl acetals described in each specification of 2,970, and a photosensitive silver halide emulsion as described in British Patent No. 1,354,186. Elimination of the use of protective polymers by means of enzymatically degrading gelatin or by preparing the light sensitive silver halide grains in the presence of a surfactant as described in US Pat. No. 4,076,539. It is possible to apply each means such as a means for performing.

The photosensitive silver halide preferably has a small grain size in order to suppress white turbidity after image formation and to obtain a good image quality. The average particle size is 0.
It is 1 μm or less, preferably 0.01 to 0.1 μm, and particularly preferably 0.02 to 0.08 μm. The shape of the silver halide is not particularly limited, and there are cubic and octahedral so-called normal crystals and non-normal crystals such as spherical, rod-shaped and tabular grains. The silver halide composition is also not particularly limited and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide and silver iodide.

The amount of silver halide is 50% by mass or less, preferably 25 to 0.
It is 1% by mass, more preferably 15 to 0.1% by mass. Although various conditions such as reaction temperature, reaction time and reaction pressure in the step of converting a part of the organic silver salt into silver halide using the above-described silver halide-forming component can be appropriately set according to the purpose of preparation. Usually, the reaction temperature is -23 ° C to 7
The reaction time is preferably 4 ° C., the reaction time is 0.1 second to 72 hours, and the reaction pressure is set to atmospheric pressure.

The photosensitive silver halide prepared by the above-mentioned various methods is, for example, a sulfur-containing compound, a gold compound,
Platinum compound, palladium compound, silver compound, tin compound,
It can be chemically sensitized with a chromium compound or a combination thereof. The chemical sensitization method and procedure are described in, for example, U.S. Pat. No. 4,036,650, British Patent No. 1,518,850 and the like, and JP-A-51-1850.
No. 22430, No. 51-78319, No. 51-811
No. 24 and other publications. In order to achieve sensitization, as described in US Pat. No. 3,980,482, when a part of an organic silver salt is converted into a photosensitive silver halide by a silver halide forming component. A low molecular weight amide compound may coexist with.

In addition, these photosensitive silver halides contain 1 to 6 elements of the Periodic Table of the Elements in order to adjust illuminance and gradation.
Group 0 metals such as Rh, Ru, Re, Ir, O
An ion such as s or Fe, or a complex or complex ion thereof can be contained. In particular, it is preferable to contain an ion or a complex ion of a metal belonging to Groups 6 to 10 of the Periodic Table of the Elements. The above metals include W, Fe, Co, Ni,
Cu, Ru, Rh, Pd, Re, Os, Ir, Pt, A
u is preferable, and when it is used in a photosensitive material for printing plate making, it is preferably selected from Rh, Re, 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 per mol of silver halide.
^-1 × 10 ^-2 mol is suitable, and preferably 1 × 10 ^-8.
˜1 × 10 ⁻⁴ mol. A compound providing an ion or a complex ion of these metals is preferably added at the time of silver halide grain formation and incorporated into the silver halide grain. Preparation of the silver halide grain, that is, nucleation, growth and physical ripening. , It may be added at any stage before and after the chemical sensitization, but it is particularly preferable to add it at the stage of nucleation, growth and physical ripening, more preferably at the stage of nucleation and growth. It is preferably added at the stage of nucleation.
Upon addition, it may be added in several divided portions, or it may be added uniformly in the silver halide grains, and JP-A-63-29603, JP-A-2-306236,
No. 3-167545, No. 4-76534, No. 6-1
As described in each of the publications such as 10146 and 5-273683, the particles may be contained with a distribution. Preferably, it has a distribution inside the particles. These metal compounds are water or a suitable organic solvent (for example, alcohols, ethers, glycols,
(Ketones, esters, amides), for example, an aqueous solution of a powder of a metal compound or an aqueous solution of a metal compound and NaCl or KCl is dissolved in water-soluble silver during grain formation. A silver halide grain is prepared by a method in which it is added to a salt solution or a water-soluble halide solution, or when a silver salt solution and a halide solution are simultaneously mixed, added as a third aqueous solution Method, a method in which a necessary amount of an aqueous solution of a metal compound is charged into a reaction vessel during grain formation, or another silver halide grain previously doped with a metal ion or a complex ion during preparation of silver halide is added and dissolved. There is a method to make it. In particular, an aqueous solution of a metal compound powder or a metal compound and N 2
A method of adding an aqueous solution in which aCl and KCl are dissolved together to a water-soluble halide solution is preferable. When added to the surface of the particles, a necessary amount of an aqueous solution of the metal compound may be added to the reaction vessel immediately after the particles are formed, during or during physical ripening, or at the end of chemical ripening.

(Spectral sensitizing dye) The spectral sensitizing dye used in the present invention may be, for example, as disclosed in JP-A-63-159841.
No. 60, No. 14034035, No. 63-231437.
No. 63-259651, 63-304242.
Nos. 63-15245, etc., U.S. Pat. No. 4,
639,414, 4,740,455, 4,741,966, 4,751,175, 4,835,096 and the like. A dye can be used. Useful sensitizing dyes used in the present invention are, for example, Research Disclosure I.
tem17643 IV-A (December 1978 p. 2
3), Item 1831X (see p. 4 of August 1978).
37) or the literature cited. 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) As the polymer binder used in the light-sensitive layer or the non-light-sensitive layer of the photothermographic image-forming material of the present invention, a material preferable as a place where silver halide, an organic silver salt or a reducing agent reacts, A material preferable for the reaction in which the heat-decoloring dye is decolored by heat of 80 to 200 ° C. or lower, or a material in which the base-generating precursor rapidly 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 being dissolved in a polar solvent containing 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 composition of the preferable polymer, the glass transition point is preferably −20 ° C. to 80 ° C., and particularly preferably −5 ° C. to 60 ° C. When the glass transition point is high, the temperature for heat development becomes high, and when the glass transition point is low, fog is liable to occur, which lowers the sensitivity and gives a soft tone.

Examples of the polymer to be used by dissolving it in the polar solvent or the like are cellulose derivatives such as hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, ethyl cellulose, starch and its derivatives, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl butyral, polyacrylic acid. Sodium, polyethylene oxide, acrylic acid amide-acrylic acid ester copolymer, styrene-maleic anhydride copolymer, polyacrylamide, sodium alginate,
Gelatin, casein, polystyrene, polyvinyl acetate,
Examples thereof include polyurethane, polyacrylic acid, polyacrylic acid ester, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, vinyl chloride-vinyl acetate copolymer, styrene-butadiene-acrylic copolymer. After further drying, after forming a film, the coating film preferably has a low equilibrium water content, and particularly low water content includes, for example, cellulose acetate, cellulose acetate butyrate, poly (methylmethacrylic acid), and the like. 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 (urethane) s, phenoxy resins, poly (vinylidene chloride), poly (epoxides),
Poly (carbonate) s, poly (vinyl acetate),
Cellulose esters and poly (amides) can be mentioned.

(Crosslinking Agent) The binder can maintain the adhesion to the lower layer and the upper layer and obtain a film strength that is less likely to be scratched by forming a film by itself. It is possible to improve film adhesion and film strength. The crosslinking agent may be added to the undercoat layer, to the AH layer, the photosensitive layer, the protective layer, the backing layer, or the backing protective layer. From the viewpoint of the stability of the coating liquid, it is preferable to add it using a static mixer immediately before coating, but it may be added at the time of preparing the coating liquid. A preferable crosslinking agent is a crosslinking agent having an isocyanate group, a vinylsulfonyl group or an epoxy group. Particularly preferred crosslinking agents include polyfunctional crosslinking agents having at least two isocyanate groups. H as a preferred crosslinking agent
1 to H13 are shown below.

[0063] (H1) Hexamethylene diisocyanate (H2) Hexamethylene diisocyanate trimer (H3) Tolylene diisocyanate (H4) Phenylene diisocyanate (H5) Xylylene diisocyanate

[0064]

[Chemical 16]

(Dye Used in AI Layer or BC Layer if Necessary) The photothermographic image-forming material of the present invention comprises an AI layer or BC layer for preventing irradiation or halation of the photothermographic image-forming material, if necessary. Is provided,
The dye used in the AI layer or the BC layer may be any dye that absorbs imagewise exposure light, but preferably the heat-discolorable dyes described in US Pat. No. 5,384,237 are mentioned. You can When the dye used is not heat-decolorable, the amount used is limited to the range that does not cause image damage to the photothermographic image-forming material, but if it is a heat-decolorable dye, a necessary and sufficient amount of dye is used. It can be added.

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

The shape of the matting agent may be either a fixed shape or an amorphous shape, but a fixed shape and a spherical shape is preferably used. The size of the matting agent is represented by the diameter when the volume of the matting agent is converted into a spherical shape. In the present invention, the particle size of the matting agent refers to the spherically converted diameter. The matting agent used in the present invention preferably has an average particle size of 0.5 to 10 μm, more preferably 1.0 to 8.0 μm.
Is. The matting agent has a monodispersity of 50 or less, more preferably 40 or less, and particularly preferably 20 or less. Here, the monodispersity of the particles is 100 divided by the standard deviation of the particle diameters by the average value of the particle diameters.
It is represented by the number multiplied by. The method of adding the matting agent according to the present invention may be a method of previously dispersing and coating in the coating solution, or a method of spraying the matting agent after coating the coating solution and before completion of drying. May be.

(Support) As the support, paper, synthetic paper,
A support such as a non-woven fabric, a metal foil or a plastic film can be used, and a composite sheet in which these are combined may be optionally used.

<Image exposure> As an exposure method, there is disclosed in Japanese Patent Laid-Open No.
Laser exposure can be carried out by the methods described in JP-A-304869, JP-A-9-311403 and JP-A-2000-10230.

<Heat Developing Device> A device for developing a photothermographic image forming material is described in JP-A No. 11-65067, 1st paragraph.
The devices described in 1-72897 and 84619 can be used.

[0071]

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

Example 1 <Preparation of Subbed Substrate> Both sides of a polyethylene terephthalate support having a thickness of 175 μm were subjected to a corona discharge treatment of 8 W / m ² · min, and one surface thereof was coated with a subbing coating solution a- 1 is applied to a dry film thickness of 0.8 μm and dried to provide an undercoat layer A-1, and the undercoating coating solution b-
1 was coated and dried to a dry film thickness of 0.8 μm to form an undercoat layer B-1.

[0073]   << Subbing coating solution a-1 >>   Butyl acrylate (30% by mass),     t-butyl acrylate (20% by mass), styrene (25% by mass),     Copolymer latex liquid of 2-hydroxyethyl acrylate (25% by mass)     (Solid content 30%) 270 g   Hexamethylene-1,6-bis (ethylene urea) 0.8 g   Make up to 1 liter with water.

[0074]   <Subbing coating solution b-1>   Butyl acrylate (40% by mass), styrene (20% by mass),     Copolymer latex liquid of glycidyl acrylate (40% by mass)     (Solid content 30%) 270 g   Hexamethylene-1,6-bis (ethylene urea) 0.8 g   Make up to 1 liter with water.

Subsequently, the undercoat layer A-1 and the undercoat layer B-1
8 W / m ² · min of corona discharge is applied to the upper surface of the undercoat layer, and the undercoating upper layer coating solution a-2 is applied and dried on the undercoating layer A-1 to a dry film thickness of 0.1 μm. Then, the undercoat layer A-2 is provided, and the following undercoat upper layer coating solution b-2 is applied and dried to a dry film thickness of 0.8 μm on the undercoat layer B-1 to have an antistatic function. An undercoat upper layer B-2 was provided.

<< Undercoating Upper Layer Coating Liquid a-2 >> Gelatin 0.4 g / m ² Mass Silica Particles (Average Particle Diameter 3 μm) 0.1 g Finish with Water to 1 L << Undercoating Upper Layer Coating Liquid b-2 >> Styrene-butadiene copolymer latex liquid (solid content 20%) 80 g Polyethylene glycol (mass average molecular weight 600) 6 g Water is added to make 1 liter.

<Preparation of silver halide grain emulsion A> Water 90
After dissolving 7.5 g of inert gelatin and 10 mg of potassium bromide in 0 ml and adjusting the temperature to 28 ° C. and pH to 3.0, 370 ml of an aqueous solution containing 74 g of silver nitrate and the same amount (98/2) 370 ml of an aqueous solution containing potassium bromide and potassium iodide in a molar ratio was added over 10 minutes by the controlled double jet method while keeping the pAg at 7.7. The sodium salt of hexachloroiridium was added in an amount of 10 ^-6 mol / 1 mol of silver in synchronism with the addition of silver nitrate. Then 4-hydroxy-6-methyl-1,3,3a, 7-
Add 0.3 g of tetrazaindene and adjust the pH to 5 with NaOH.
The cubic silver iodobromide grains having an average grain size of 0.036 μm, a variation coefficient of the projected diameter area of 8% and a [100] plane ratio of 87% were obtained. 0.1 g of phenoxyethanol after desalting by coagulating and settling this emulsion with gelatin coagulant
Was added to adjust the pH to 5.9 and pAg to 7.5 to obtain a silver halide grain emulsion A.

<Preparation of Water-Dispersed Organic Silver Salt> Behenic acid 111.4 g and arachidic acid 83.8 in 4720 ml of pure water.
g, and 54.9 g of stearic acid were dissolved at 80 ° C. Next, while stirring at high speed, 540.2 ml of a 1.5 mol / liter sodium hydroxide aqueous solution was added, and 6.9 ml of concentrated nitric acid was added.
Was added and then cooled to 55 ° C. to obtain an organic acid sodium salt solution. While maintaining the temperature of the above-mentioned sodium salt of organic acid at 55 ° C., the silver halide grain emulsion A (silver 0.038
(Including mol) and 420 ml of pure water were added and stirred for 5 minutes. Next, 760.6 ml of 1 mol / l silver nitrate solution
Was added over 2 minutes, the mixture was stirred for another 20 minutes, and the water-soluble salts were removed by filtration. After that, the conductivity of the filtrate is 2μ
Washing with deionized water and filtration were repeated until S / cm was reached, and water was added to a predetermined concentration for finishing.

<Coating of Photosensitive Layer and BC Layer> Samples were prepared by successively forming the following layers on the support having the undercoat layer. The drying was carried out at 45 ° C. for 1 minute.

<< Coating on BC layer >> On the back surface side, a coating solution prepared by adding water to an aqueous solution or dispersion of the following heat-bleachable dye composition is further coated and dried in the following coating amounts. To form a BC layer.

<< BC layer coating >> Inert gelatin 1.8 g / m ² Dye: C1 1.2 × 10 ⁻⁵ mol / m ² Activator: N-propyloctylsulfonamidoacetic acid 0.02 g / m ² Dihexylsulfosuccinic acid Sodium salt 0.02 g / m ² Hardener: 1,2-bis (vinylsulfonamide) ethane 0.02 g / m ² << Application of BC protective layer >> Inert gelatin 1.1 g / m ² Hardener: 1, 2-bis (vinylsulfonamide) ethane 0.01 g / m ² Activator: N-propyl perfluorooctyl sulfonamide acetic acid 0.02 g / m ² Matting agent (PMMA: average particle size 5 μm) 0.12 g / m ² << photosensitive layer side of the coating "" coating the AI layer "binders: PVB-1 0.4g / m ² dye: C1 (BC layer and the same kind) coating of the following composition for a photosensitive layer formed was dissolved in methyl ethyl ketone solvent Liquid was prepared. This coating solution was kept at around 35 ° C. and coated and dried so as to have the following coating amounts. An amount of 1.36 g / m ² silver preparation was mixed with the polymer binder.

Binder: PVB-1 (same kind as AI layer) 2.6 g / m ² Phosphorene compound: described in Table 1 3.2 × 10 ⁻⁴ equivalent / m ² Spectral sensitizing dye A1 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: BP4 3.3 mmol / m ²

[0083]

[Chemical 17]

<< Surface Protective Layer >> A coating solution prepared by adding the following composition was coated and dried on the photosensitive layer so as to have the following coating amounts to form a surface protective layer.

Cellulose acetate butyrate 1.2 g / m ² 4-methylphthalic acid 0.7 g / m ² tetrachlorophthalic acid 0.2 g / m ² tetrachlorophthalic anhydride 0.5 g / m ² silica matting agent (average Particle size 5 μm) 0.5 g / m ² <Evaluation of photographic performance> The above-prepared sample was divided into two and one was stored at 25 ° C. in an atmosphere of 60% RH for 3 days, and then exposed to a semiconductor laser of 810 nm. The sample was exposed to light with a sensitometer of No. 2 and heated at 120 ° C. for 8 seconds, and the obtained sample was used as a normal humidity sample. The other one was stored in a high humidity atmosphere of 35 ° C. and 78% RH for 3 days, and then similarly exposed and developed to obtain a high humidity sample. Laser exposure and development of the above normal humidity sample were performed at 25 ° C ± 1 ° C relative humidity 54% ±.
I went to a room where the humidity was adjusted to 1%.

The sensitivity and fog of the normal humidity sample and the high humidity sample were measured with a densitometer. The sensitivity was evaluated by the reciprocal of the ratio of the exposure dose that gives a density 0.3 higher than the fog density, and was expressed by relative evaluation using the sample 101 as a reference (100). And the difference in sensitivity. The smaller the increase in fog and the decrease in sensitivity, the better the storage stability.

[0087]

[Table 1]

From Table 1, the photographic properties (sensitivity and fog characteristics) during heat development and the storage stability are excellent, but the samples not containing the phosphorene compound of the present invention are superior to other samples in heat development. It can be seen that the photographic performance and storability are poor.

Example 2 A sample was prepared and its performance was evaluated in the same manner as in Example 1. Here, the phthalazine compound was additionally added to the AI layer and the photosensitive layer in the following amounts to evaluate fog, sensitivity and storability. did. AI layer: 1.2 × 10 ^-5 mol / m ² Photosensitive layer: 2.1 × 10 ^-4 mol / m ²

[0090]

[Table 2]

From Table 2, it can be seen that the use of the phosphorene compound and the phthalazine compound of the present invention results in excellent fog and sensitivity, and further excellent storage stability.

Example 3 A sample was prepared in the same manner as in Example 1, except that a polyhalomethane compound (3.6 × 10 ⁻⁴ mol / silver 1 mol) and a phthalazine compound (2.6 × 10 ⁻⁴ mol / silver) were used. 1 mol), a bisphenol compound (3.8 × 10 ⁻⁴ mol / silver 1 mol),
A crosslinking agent (2.6 × 10 ⁻⁴ mol / m ² ) was added to the photosensitive layer, and the photographic performance and storability were evaluated in the same manner as in Example 1,
The test of the printed silver was as follows.

The resulting developed sample was illuminated with a 1000 lux fluorescent lamp. A diffusion sheet was interposed between the fluorescent lamp and the test sample so that the light irradiation was uniform. Although the irradiation time was changed, the fog value (printed-out fog) after irradiation for 3 hours is shown in Table 3 here. The residual color was visually evaluated on a scale of 5 levels. Rank 5 is the best level with no residual color, rank 1 is the worst level, and rank 3 is the level that has no practical problems.

[0094]

[Table 3]

From Table 3, it can be seen that when the phosphorene compound, the phthalazine compound, the polyhalomethane compound, the bisphenol compound and the crosslinking agent of the present invention are used, printed silver and fogging at the time of thermal development are suppressed and the storage stability is improved.

[0096]

According to the present invention, high sensitivity and low fog are imparted, fog due to baked silver after development is suppressed, and further the raw storage stability before development and the image storage stability after development are excellent and It was possible to provide a photothermographic image-forming material having little residual color and stable color tone.

Claims (6)

[Claims] 1. A photothermographic image forming material having a photosensitive layer containing photosensitive silver halide grains, an organic silver salt, a reducing agent and a binder on a support, wherein the photothermographic material contains a phosphorene compound. Photographic material. 2. The photothermographic image-forming material according to claim 1, wherein the phosphorene compound is a compound represented by the following general formula (1). [Chemical 1] [In the formula, R ¹ represents a halogen atom, a cyano group, an alkoxy group, a hydroxy group, a substituted amino group, an alkyl group having 1 to 30 carbon atoms which may have a substituent, an alkenyl group, an alkynyl group, or an aromatic group. Represents a group selected from a group and a heterocyclic group. n represents an integer of 1 to 4. When two or more R ^1's are adjacent to each other, they may be bonded to each other to form a ring. R ¹ when n is 2 to 4 may be different or the same. Z ₁ represents a 5- or 6-membered ring group which may have a substituent. ] 3. The photothermographic image forming material according to claim 1, wherein the photosensitive layer of the photothermographic image forming material or a layer adjacent to the photosensitive layer contains a phthalazine compound. 4. The photothermographic image-forming material according to claim 1, wherein the photosensitive layer or a layer adjacent to the photosensitive layer contains a polyhalomethane compound. 5. The photothermographic image-forming material according to claim 1, wherein the photosensitive layer or a layer adjacent to the photosensitive layer contains a bisphenol compound. 6. The cross-linking agent for cross-linking the binder of the photosensitive layer or a layer adjacent to the photosensitive layer is at least one selected from an isocyanate compound, a vinyl sulfone compound and an epoxy compound. The photothermographic image forming material according to any one of 1 to 5.