JP2000053682A - Production of organosilver salt dispersion and heat developing photosensitive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an organosilver salt dispersion having excellent dispersion of silver salt, a narrow particle size distribution, useful as a heat developing photosensitive material free from fog, etc., by making a raw material liquid into a high-speed flow by pressure and passing the liquid through a high-pressure grinding part. SOLUTION: A raw material liquid comprising an organosilver salt and a solvent (e.g. a silver aliphatic or a nitrogen-containing heterocyclic carboxylate is added to 2-butanol to give 10-50 wt.% of the carboxylate based on the solvent) is pressurized, for example, under 200-1,000 kg/cm2 into a high-speed flow (e.g. 140-450 m/sec) and passed through a high-pressure grinding part. The high- pressure grinding part is formed by arranging zones 1 and 2 for bending the flow channel of the passing raw material liquid approximately at right angles in a dispersing apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an organic silver salt dispersion in which the dispersibility of the organic silver salt is improved and the particle size distribution of the organic silver salt particles is narrow, and the organic silver produced by the method. The present invention relates to a photothermographic material using a salt dispersion.

[0002]

2. Description of the Related Art In recent years, in the medical field, X-ray CT, MR
As a means for outputting a diagnostic image such as I, a method has been adopted in which a photosensitive material is scanned with a laser beam and exposed to form an image. However, these photosensitive materials have been subjected to wet development processing after imagewise exposure by scanning with a laser beam and subjected to diagnosis.

In wet processing of photosensitive materials, waste liquid is a problem in terms of environmental protection. In recent years, it has been strongly desired to reduce the amount of processing waste liquid from the viewpoint of space saving.

Therefore, there has been a demand for a technique relating to a photothermographic material capable of efficiently exposing with a laser imager and forming a high-resolution and clear black image.

As this technique, for example, US Pat.
Nos. 152,904, 3,487,075 and D.I. "Dry Silver Photographic" by Morgan
Materials) "(Handbook of
Imaging Materials, Marcel
Dekker, Inc. 48, 1991), a photothermographic material containing an organic silver salt, photosensitive silver halide grains and a reducing agent on a support is known. Further, a heat-developable material which does not contain photosensitive silver halide grains and forms an image by thermal energy is widely known.

An organic silver salt is an essential component of the photothermographic material and the photothermographic material, and many methods for producing the same have been disclosed. For example, a dispersion machine such as a ball mill, an attritor, a sand mill, and a homomixer has been used for dispersion of the organic silver salt. However, both devices
There have been problems such as low dispersion efficiency and difficulty in achieving atomization. Japanese Patent Application Laid-Open No. Hei 8-137404 discloses a method for producing a dispersion of an organic silver salt by a method of generating a plurality of high-speed flows of a raw material liquid containing at least an organic silver salt and causing the raw material liquid streams to collide with each other. It has been disclosed.

However, when the dispersing method of the above patent is used, the dispersibility of the organic silver salt is certainly improved, but the particle size distribution of the dispersed organic silver salt particles is widened, and the organic silver salt is manufactured using the dispersion. Heat-developable photosensitive material does not increase sensitivity,
There were also problems such as high fog. Therefore, there has been a demand for a method for producing an organic silver salt dispersion having good dispersibility of organic silver salt particles and having a narrow particle size distribution.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing an organic silver salt dispersion in which the dispersibility of the organic silver salt is improved and the particle size distribution of the organic silver salt particles is narrow. The present invention relates to a photothermographic material produced by the above-described method, having reduced fog and improved sensitivity.

[0009]

The above objects of the present invention have been attained by the following items.

[0010] 1. An organic silver salt dispersion, wherein a high-speed flow is generated by applying pressure to a raw material liquid comprising at least an organic silver salt and a solvent, and the high-speed flow passes through a high-pressure pulverizing section, whereby the organic silver salt is dispersed. Method of manufacturing a product.

2. 2. A photothermographic material comprising an organic silver salt dispersion produced by the production method as described in 1 above.

Hereinafter, the present invention will be described in detail.

The method for dispersing the organic silver salt used in the present invention will be described.

In the present invention, a raw material liquid containing an organic silver salt in a high-speed flow generated by applying pressure using a dispersing apparatus having a high-pressure pulverizing section as shown in FIG. 1 or 2 is used in the present invention. By passing the mixture through a high-pressure pulverizing section, an organic silver salt dispersion having good dispersibility of the organic silver salt and a small particle size distribution of the organic silver salt particles can be obtained.

In the present invention, as shown in FIGS. 1 and 2, the high-pressure pulverizing section refers to an area where the flow path of the raw material liquid passing through the dispersing device is bent at substantially a right angle. The organic silver salt is uniformly dispersed when the high-speed flow of the raw material liquid passes, and an organic silver salt dispersion having a narrow particle size distribution of the organic silver salt particles is obtained.

In the present invention, the term "substantially perpendicular" means that when the flow path of the raw material liquid is directed to a flow path having a different direction, the angle of the corner formed by each flow path is preferably 80 to 110 degrees. And more preferably 85 to 95 degrees.

The high pressure applied to a raw material solution containing at least an organic silver salt and a solvent is 200 to 1,000 kgf / cm.
² is preferably used, but in order to further improve the dispersibility, 280 to 700 kgf / cm ² is more preferably used.

The high-speed flow of the raw material liquid generated by applying the high pressure described above is preferably 140 to 450 m / sec, and more preferably 230 to 370 m / sec.

Regarding the narrow particle size distribution of the organic silver salt particles, the high-speed flow generated by applying a high pressure to the raw material liquid containing at least the organic silver salt and the solvent passes through the high-pressure pulverizing section as described above. I think it's because.

The raw material liquid used in the present invention contains at least an organic silver salt and a solvent.

Preferred examples of the solvent include water, alcohols, esters, aromatic hydrocarbons, ketones and the like.

Examples of the alcohol include methanol, ethanol, propanol and the like.

Examples of the esters include ethyl acetate and butyl acetate.

Examples of the aromatic hydrocarbons include benzene, toluene, xylene and the like.

Examples of the above ketones include acetone, 2-butanone (MEK) and the like.

Among the above-mentioned solvents, acetone and 2-butanone (MEK) are preferably used from the viewpoints of the dispersibility of the organic silver salt and the narrow particle size distribution of the organic silver salt particles.
Particularly preferably used is 2-butanone (MEK)
It is.

The ratio of the organic silver salt to the solvent used in the present invention is such that the amount of the organic silver salt is 10 to the solvent.
50 wt% is preferable, and 20 to 40 wt% is more preferable.
%.

The organic silver salt used in the present invention is a reducible silver source, and is an organic acid containing a reducible silver ion source. Examples of the organic acid used in the present invention include an aliphatic carboxylic acid, a carbocyclic carboxylic acid, a heterocyclic carboxylic acid, and a heterocyclic compound.
An aliphatic carboxylic acid having 0, preferably 15 to 25 carbon atoms) and a heterocyclic carboxylic acid having a nitrogen-containing heterocyclic ring are preferably used. Moreover, when the ligand is 4.0-10.
Organic silver salt complexes having a total stability constant for silver ions of 0 are also useful.

Examples of the organic silver salt used in the present invention include Research Disclosure No. 170.
And silver salts of fatty acids (eg, silver salts of gallic acid, oxalic acid, behenic acid, arachidic acid, stearic acid, palmitic acid, lauric acid, etc.); Carboxyalkylthiourea salts (eg, 1- (3-carboxypropyl) thiourea, 1- (3-carboxypropyl) -3,3-dimethylthiourea); polymerization reaction products of aldehydes and hydroxy-substituted aromatic carboxylic acids (E.g., aldehydes (formaldehyde, acetaldehyde, butyraldehyde, etc.) and hydroxy-substituted aromatic carboxylic acids (e.g., salicylic acid, benzoic acid, 3,5-dihydroxybenzoic acid, 5,5-thiodisalicylic acid, etc.) Silver complex or the like of a polymerization reaction product of), a silver salt or complex of a thione (for example, 3- (2-carbo) (Silethyl) -4-hydroxymethyl-4-thiazoline-2-thione and 3-carboxymethyl-4-thiazoline-2-thione), imidazole, pyrazole, urazole, 1,2,4-thiazole and 1H-tetrazole, -Amino-5-benzylthio-1,2,4-triazole and benzotriazole, and complexes and salts of silver with nitrogen acids; silver salts such as saccharin and 5-chlorosalicylaldoxime; and silver salts of mercaptides . Among the organic silver salts described above, silver salts of fatty acids are preferably used, and silver behenate, silver arachidate and silver stearate are more preferably used.

Further, the organic silver salt used in the present invention preferably has an average particle size of 1 μm or less and is monodispersed. The average particle size of the organic silver salt refers to the diameter of a sphere equivalent to the volume of the organic silver salt particles when the particles of the organic silver salt are, for example, spherical, rod-shaped, or tabular particles. The average particle size is preferably from 0.01 μm to 0.8 μm, particularly preferably from 0.05 μm to 0.5 μm. The monodispersion has the same meaning as that of silver halide, and the monodispersity is preferably 1% to 30%.

In the present invention, the organic silver salt has an average particle size of 1
It is more preferable that the particles are monodisperse particles having a particle size of not more than μm.

As the organic silver salt particles, it is preferable that tabular grains account for at least 60% of the total projected area of all organic silver grains. The tabular grains used in the present invention are grains having an aspect ratio (abbreviated as AR) of 3 or more, which is a ratio between the average particle diameter and the thickness, which is represented by the following formula.

AR = average particle size (μm) / thickness (μm) The organic silver salt particles are dispersed and pulverized together with a binder and a surfactant using, for example, a ball mill.
The shape described above is also possible.

In the present invention, in order to prevent devitrification of the photothermographic material, the total amount of silver halide and organic silver salt is 0.5 g or more and 2.2 g or less per m ² in terms of silver. Is preferred. With this range, a high-contrast image can be obtained. The amount of silver halide based on the total amount of silver is
The weight ratio is 50% or less, preferably 25% or less, more preferably between 0.1% and 15%. This silver halide may be added to the organic silver salt dispersion by any method,
At this time, the silver halide is preferably arranged so as to be close to the organic silver salt.

The silver halide grains used in the present invention function as an optical sensor. In the present invention, the average particle size is preferably 0.1 μm or less, more preferably 0.01 μm to 0.1 μm, particularly preferably 0.01 μm to 0.1 μm, in order to suppress white turbidity after image formation and obtain good image quality. It is 0.02 μm to 0.08 μm.

The term "grain size" as used herein refers to the length of a ridge of a silver halide grain when the silver halide grain is a cubic or octahedral so-called normal crystal. In the case of non-normal crystals, for example, in the case of spherical, rod-shaped, or tabular grains, the diameter of a sphere equivalent to the volume of silver halide grains is indicated. Further, the silver halide is preferably monodispersed.

The term “monodispersion” as used herein means a case where the degree of monodispersion determined by the following equation is 40% or less. In the present invention, the monodispersity is more preferably 30% or less, particularly preferably 0.1% or more and 20% or less.

Monodispersity = (standard deviation of particle size) / (average value of particle size) × 100 In the present invention, the silver halide particles have an average particle size of 0.1.
μm or less and more preferably monodisperse particles,
By setting it in this range, the granularity of the image is also improved.

The shape of the silver halide grains is not particularly limited, but it is preferable that the ratio occupied by the Miller index [100] plane is high, and this ratio is 50% or more, and more preferably 7%.
It is preferably at least 0%, particularly preferably at least 80%. The ratio of the Miller index [100] plane is determined by the T.M. Tani, J .; Imaging Sci. , 29,
165 (1985).

Another preferred form of silver halide is tabular grains. The term "tabular grain" as used herein means that the thickness in the vertical direction is h.mu.
When m, the aspect ratio = r / h means 3 or more. Among them, the aspect ratio is more preferably 3 or more and 50 or less. The particle size is preferably 0.1 μm or less, more preferably 0.01 μm to 0.08 μm. These are described in U.S. Pat. Nos. 5,264,337, 5,314,798, and 5,320,958, and the desired tabular grains can be obtained with reference to the above patents. .

When these tabular grains are used in the present invention, the sharpness of an image is further improved. The halogen composition is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide, and silver iodide. AgX particles used in the present invention are P.A. Glafk
Chimie et Physique P
photographique (Paul Montel)
G., 1967); F. Duffin's Pho
graphical Emulsion Chemis
try (published by The Focal Press, 1966)
Year), V. L. Mak by Zelikman et al
ing and Coating Photograph
hic Emulsion (The Focal Pr
ess, 1964) and the like, and can be prepared using an Ag emulsion prepared by a method described in US Pat.

The silver halide used in the present invention is preferably contained in an amount of 0.75 to 30% by weight based on the organic silver salt.

The silver halide used in the present invention preferably contains ions or complex ions of metals belonging to Groups 6 to 11 of the periodic table. Examples of the above metals include W, Fe, Co, Ni, Cu, Ru, Rh, Pd,
Re, Os, Ir, Pt, and Au are preferred.

The ions of these metals can be introduced into silver halide in the form of complex ions. In the present invention, the transition metal complex ion is preferably a six-coordinate complex ion represented by the following general formula.

In the general formula [ML ₆ ] ^m , M is a transition metal selected from elements of Groups 6 to 11 of the periodic table, L is a bridging ligand, and m is 0,-, 2- or 3- . Specific examples of the ligand represented by L include halides (fluoride, chloride, bromide and iodide), cyanide, cyanate, thiocyanate, selenocyanate,
Terrocyanate, each ligand of azide and aquo, nitrosyl, thionitrosyl and the like, preferably aquo,
And nitrosyl and thionitrosyl. If an aquo ligand is present, it preferably occupies one or two of the ligands. L may be the same or different.

Particularly preferred examples of M are rhodium (Rh), ruthenium (Ru), rhenium (Re), iridium (Ir) and osmium (Os).

Specific examples of transition metal complex ions are shown below, but the present invention is not limited to these.

[0048] 1: [RhCl _6] ^3- 2: [RuCl _6] ^3- 3: [ReCl _6] ^3- 4: [RuBr _6] ^3- 5: [OsCl _6] ^3- 6: [IrCl _6] ^{4 -} 7: [Ru (NO) Cl _5] ^2- 8: [RuBr ₄ (H ₂ O)] ^2- 9: _{[Ru (NO) (H 2 O} ) Cl 4 ] ^- 10: [RhCl ₅ (H ₂ O)] ^2- 11: [Re (NO) Cl _5] ^2- 12: [Re (NO) CN _5] ^2- 13: [Re (NO) ClCN _4] ^2- 14: [Rh (NO) ₂ Cl _4] ^- 15: _{[Rh (NO) (H 2 O} ) Cl 4 ] ^- 16: [Ru (NO) CN _5] ^2- 17: [Fe (CN) _6] ^3- 18: [Rh (NS) Cl _5] ^2- 19: [Os (NO) Cl _5] ^2- 20: [Cr (NO) Cl _5] ^2- 21: [Re (NO) Cl _5] ^- 22: [Os (NS) Cl ₄ (TeCN )] ^2- 23: Ru (NS) Cl _5] ^2- 24: _{[Re (NS) Cl 4 (SeCN} ) ] ^2- 25: [Os (NS) Cl (SCN) 4 ] ^2- 26: [Ir (NO) Cl _5] ^{2 -} 27: [Ir (NS) Cl _5] ^2- also may with ions or complex ions one kind of these metals, the metal of the same kind of metal or different may be used alone or in combination. The content of these metal ions or complex ions is generally 1 × 1 per mole of silver halide.
0 ^-9 to 1 × 10 ^-2 mol is suitable, preferably 1 × 1
It is 0 ^-8 to 1 × 10 ^-4 mol.

Compounds which provide these metal ions or complex ions are added when silver halide grains are formed,
It is preferably incorporated into silver halide grains, and may be added at any stage before and after preparation of silver halide grains, that is, nucleation, growth, physical ripening, and chemical sensitization. It is preferably added at the stage of physical ripening, more preferably at the stage of nucleation and growth, and most preferably at the stage of nucleation.

In the addition, the compound may be added in several divided portions, may be added uniformly in the silver halide grains, or may be added uniformly in the silver halide grains.
-306236, 3-167545, 4-76
No. 534, No. 6-110146, No. 5-273683
As described in Japanese Patent Application Laid-Open No. H10-284, etc., the particles can be contained in the particles with a distribution. Preferably, a distribution can be provided inside the particles.

These metal compounds can be added by dissolving them in water or a suitable organic solvent (eg, alcohols, ethers, glycols, ketones, esters, amides). A method in which an aqueous solution of a powder or an aqueous solution in which a metal compound and NaCl and KCl are dissolved together is added to a water-soluble silver salt solution or a water-soluble halide solution during grain formation, or a silver salt solution and a halide solution are used. When they are mixed simultaneously, they are added as a third aqueous solution to prepare silver halide grains by a three-liquid simultaneous mixing method, a method in which a required amount of an aqueous solution of a metal compound is charged into a reaction vessel during grain formation, or a method in which halogen is added. There is a method in which another silver halide grain doped with metal ions or complex ions in advance during the preparation of silver halide is added and dissolved. In particular, a method of adding an aqueous solution of a powder of a metal compound or an aqueous solution in which a metal compound and NaCl and KCl are dissolved together is added to a water-soluble halide solution.

When adding to the surface of the particles, a required amount of an aqueous solution of a metal compound can be introduced into the reaction vessel immediately after the formation of the particles, during or at the end of physical ripening, or at the time of chemical ripening.

The silver halide grains used in the present invention may or may not be desalted after grain formation. When desalting is performed, methods known in the art such as a noodle method and a flocculation method are used. Can be desalted by washing with water.

The silver halide grains used in the present invention are preferably chemically sensitized. Preferred chemical sensitization methods are sulfur sensitization, as is well known in the art,
Selenium sensitization and tellurium sensitization can be used. Further, a noble metal sensitization method or a reduction sensitization method of a gold compound, platinum, palladium, an iridium compound or the like can be used. As the compound preferably used in the sulfur sensitization method, the selenium sensitization method, and the tellurium sensitization method, known compounds can be used, and the compounds described in JP-A-7-128768 can be used. Examples of tellurium sensitizers include diacyl tellurides, bis (oxycarbonyl) tellurides,
Bis (carbamoyl) tellurides, diacyl tellurides, bis (oxycarbonyl) ditellurides, bis (carbamoyl) ditellurides, compounds having a P = Te bond, tellurocarboxylates, Te-organyltellurocarboxylates, Use of (poly) tellurides, tellurides, tellurols, telluroacetals, tellurosulfonates, compounds having a P-Te bond, Te-containing heterocycles, tellurocarbonyl compounds, inorganic tellurium compounds, colloidal tellurium, etc. Can be. Compounds preferably used for the noble metal sensitization method include, for example, chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, gold selenide, US Pat. No. 2,448,060, British Patent No. 618,061 and the like. Can be preferably used.

Specific compounds for the reduction sensitization method include, for example, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds and the like in addition to ascorbic acid and thiourea dioxide. be able to. Further, reduction sensitization can be achieved by ripening the emulsion while maintaining the pH of the emulsion at 7 or more or the pAg at 8.3 or less. Further, reduction sensitization can be achieved by introducing a single addition portion of silver ion during grain formation.

The photothermographic material of the present invention preferably contains a reducing agent. Examples of suitable reducing agents are described in U.S. Patent Nos. 3,770,448, 3,773,512, 3,593,863, and Research Dis.
Closure Nos. 17029 and 29996, and include: Aminohydroxycycloalkenones (for example, 2-hydroxypiperidino-2)
-Cyclohexenone); aminoreductone esters (e.g., piperidinohexose reductone monoacetate) as precursors of reducing agents; N-hydroxyurea derivatives (e.g., N-p-methylphenyl-N-hydroxy) Urea); hydrazones of aldehydes or ketones (eg, anthracene aldehyde phenylhydrazone); phosphoramidophenols; phosphoramidoanilines; polyhydroxybenzenes (eg, hydroquinone, t-butyl-hydroquinone, isopropylhydroquinone, and (2) , 5-dihydroxy-phenyl) methylsulfone); sulfhydroxamic acids (eg, benzenesulfhydroxamic acid); sulfonamidoanilines (eg, 4- (N-
Methanesulfonamido) aniline); 2-tetrazolylthiohydroquinones (for example, 2-methyl-5- (1-
Phenyl-5-tetrazolylthio) hydroquinone); tetrahydroquinoxalines (e.g., 1,2,3,4-
Amidooxins; Azines (eg, a combination of an aliphatic carboxylic acid arylhydrazide and ascorbic acid); a combination of polyhydroxybenzene and hydroxylamine, reductone and / or hydrazine; Hydroxamic acids; Azines and sulfone Combinations of amidophenols; α-cyanophenylacetic acid derivatives; bis-β-naphthol and 1,3
5-pyrazolones; sulfonamidophenol reducing agents; 2-phenylindane-1,3-dione and the like; chromans;
Dihydropyridines (for example, 2,6-dimethoxy-
3,5-dicarbethoxy-1,4-dihydropyridine); bisphenols (for example, bis (2-hydroxy-3-t-butyl-5-methylphenyl) methane, bis (6-hydroxy-m-tri) mesitol (Mesi
tol), 2,2-bis (4-hydroxy-3-methylphenyl) propane, 4,5-ethylidene-bis (2-
t-butyl-6-methyl) phenol), ultraviolet-sensitive ascorbic acid derivatives and 3-pyrazolidones. Among them, particularly preferred reducing agents are hindered phenols.
Examples of the hindered phenols include compounds represented by the following general formula (A).

[0057]

Embedded image

In the formula, R is a hydrogen atom or a group having 1 carbon atom.
To 10 alkyl groups (for example, butyl group, 2,4,4-
R ′ and R ″ represent an alkyl group having 1 to 5 carbon atoms (eg, a methyl group, an ethyl group, a t-butyl group, etc.).

Specific examples of the compound represented by formula (A) are shown below. However, the present invention is not limited to these.

[0060]

Embedded image

[0061]

Embedded image

The amount of the reducing agent including the compound represented by formula (A) is preferably 1 × 1 per mol of silver.
It is from 0 ^-2 to 10 mol, especially from 1 x 10 ^{-2 to} 1.5 mol.

The photothermographic material of the present invention may contain an antifoggant. What is known as the most effective antifoggant is mercury ion. The use of a mercury compound as an antifoggant in a light-sensitive material is disclosed in, for example, US Pat. No. 3,589,903. However, mercury compounds are environmentally unfriendly. Non-mercury antifoggants include, for example, US Pat.
Nos. 075 and 4,452,885 and JP-A-59-5959.
Antifoggants such as those disclosed in US Pat.

Particularly preferred non-mercury antifoggants are US Pat. Nos. 3,874,946 and 4,756,999.
-C (X ₁ ) (X ₂ ) as disclosed in US Pat.
(X ₃ ) (where X ₁ and X ₂ represent a halogen atom, X ₃
Is a heterocyclic compound having at least one substituent represented by the following formula: As examples of suitable antifoggants, compounds described in paragraphs [0030] to [0036] of JP-A-9-288328 are preferably used.

Examples of another preferred antifoggant include JP-A-9-90550, paragraph [006].
2] to [0063]. Still other suitable antifoggants are described in U.S. Pat.
8,523 and British Patent Application No. 9300147.7.
No. 9311790.1.

It is preferable to add a toning agent to the photothermographic material of the present invention for the purpose of improving the silver tone after development. Examples of suitable toning agents are Research Discl
No. 17029, which includes the following:

Imides (eg, phthalimide); cyclic imides, pyrazolin-5-ones, and quinazolinones (eg, succinimide, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and , 4-thiazolidinedione); naphthalimides (eg, N-hydroxy-1,8-naphthalimide); cobalt complexes (eg, hexamine trifluoroacetate of cobalt), mercaptans (eg, 3
-Mercapto-1,2,4-triazole); N- (aminomethyl) aryldicarboximides (for example,
N- (dimethylaminomethyl) phthalimide); blocked pyrazoles, isothiuronium (isoth
uronium) derivatives and certain photobleaching combinations (eg, N, N'-hexamethylene (1-carbamoyl-3,5-dimethylpyrazole), 1,8-
A combination of (3,6-dioxaoctane) bis (isothiuronium trifluoroacetate) and 2- (tribromomethylsulfonyl) benzothiazole; a merocyanine dye (e.g., 3-ethyl-5-((3-ethyl -2-benzothiazolinylidene (benzothiazolinylidene))-1-methylethylidene) -2-thio-2,4
Oxazolidinedione); phthalazinone, a phthalazinone derivative or a metal salt of these derivatives (for example, 4-
(1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7-dimethyloxyphthalazinone, and 2,3
-Dihydro-1,4-phthalazinedione); a combination of phthalazinone and a sulfinic acid derivative (for example, 6-chlorophthalazinone + sodium benzenesulfinate or 8-methylphthalazinone + sodium p-trisulfonate); phthalazine + phthalate Combinations of acids; phthalazine (including adducts of phthalazine) and maleic anhydride, and phthalic acid, 2,3-naphthalenedicarboxylic acid or o-phenylene acid derivatives and anhydrides thereof (for example,
Combination with at least one compound selected from phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride; quinazolinediones, benzoxazine, naloxazine derivatives; benzoxazine-2,4-dione (Eg, 1,3-benzoxazine-2,4-dione); pyrimidines and asymmetric-triazines (eg, 2,4-dihydroxypyrimidine), and tetraazapentalene derivatives (eg,
3,6-dimercapto-1,4-diphenyl-1H, 4
H-2,3a, 5,6a-tetraazapentalene). Preferred toning agents are phthalazone or phthalazine.

The photothermographic materials of the present invention include, for example, JP-A-63-159841, JP-A-60-140335, JP-A-63-231437, JP-A-63-259651, and JP-A-6-259561.
3-304242, 63-15245, U.S. Pat. Nos. 4,639,414, 4,740,455, 4,741,966, 4,751,175, and 4,835. No. 096 can be used.

Useful sensitizing dyes for use in the present invention include, for example, Research Disclosure Item
17643 IV-A (p. 23, December 1978) and Item 1831X (p. 437, August 1978). 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, JP-A-9-34078, JP-A-9-54409, and JP-A-9-806
The compounds described in No. 79 are preferably used.

In the present invention, a mercapto compound, a disulfide compound, and a thione compound are contained in order to control development by suppressing or accelerating development, to improve spectral sensitization efficiency, and to improve storage stability before and after development. be able to.

When a mercapto compound is used in the present invention, it may be of any structure,
Those represented by -SS-Ar are preferred. In the formula, M is a hydrogen atom or an alkali metal atom, and Ar represents an aromatic ring or a condensed aromatic ring having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms.

As the aromatic ring, an aromatic carbon ring and a heteroaromatic ring are used. In the present invention, a heteroaromatic ring is preferably used. As the heteroaromatic ring, for example, benzimidazole, naphthymidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzotellurazole, imidazole, oxazole, pyrazole, triazole, thiadiazole, tetrazole, triazine, pyrimidine, Pyridazine, pyrazine, pyridine, purine, quinoline or quinazolinone. The heteroaromatic ring includes, for example, a halogen atom (eg, Br and Cl), a hydroxy group, an amino group, a carboxy group, an alkyl group (eg, one or more carbon atoms, preferably
Having a substituent selected from the group consisting of those having from 1 to 4 carbon atoms) and alkoxy groups (e.g., having at least one carbon atom, preferably having from 1 to 4 carbon atoms). Is also good. Examples of the mercapto-substituted heteroaromatic compound include 2-mercaptobenzimidazole and 2-mercaptobenzimidazole.
Mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-mercapto-5-methylbenzothiazole, 3-mercapto-1,2,4-triazole,
-Mercaptoquinoline, 8-mercaptopurine, 2,
3,5,6-tetrachloro-4-pyridinethiol,
-Hydroxy-2-mercaptopyrimidine, 2-mercapto-4-phenyloxazole and the like,
The present invention is not limited to these.

In the present invention, a matting agent is preferably contained on the photosensitive layer side, and a matting agent is preferably provided on the surface of the photosensitive material in order to prevent the image after thermal development from being damaged. It is preferable that the content of the agent is 0.5 to 30% by weight based on all binders on the emulsion layer side.

The material of the matting agent used in the present invention may be either an organic substance or an inorganic substance.

For example, as the inorganic substance, Swiss Patent No. 3
Silica described in No. 30,158, French Patent No. 1,29
No. 6,995, etc., British Patent No. 1,17
Alkaline earth metals or carbonates such as cadmium and zinc described in 3,181 and the like can be used as a matting agent. As organic substances, US Pat. No. 2,322,03
7, starch derivatives described in Belgian Patent No. 625,451 and British Patent No. 981,198, polyvinyl alcohol described in Japanese Patent Publication No. 44-3643, and Swiss Patent No. 330,158. Polystyrene or polymethacrylate described in U.S. Pat.
Organic matting agents such as polyacrylonitrile described in No. 79,257 and polycarbonate described in U.S. Pat. No. 3,022,169 can be used.

The shape of the matting agent may be either regular or irregular, but is preferably regular and spherical. 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 diameter of the matting agent indicates the diameter converted into a sphere.

The matting agent used in the present invention preferably has an average particle size of 0.5 μm to 10 μm, more preferably 1.0 μm to 8.0 μm. The matting agent has a coefficient of variation of the particle size distribution of preferably 50% or less, more preferably 40% or less, and particularly preferably 30% or less.

Here, the variation coefficient of the particle size distribution is a value represented by the following equation.

(Standard deviation of particle size) / (Average value of particle size) × 100 The matting agent used in the present invention can be contained in any constituent layer, but in order to achieve the object of the present invention, It is preferably a constituent layer other than the photosensitive layer, and more preferably the outermost layer as viewed from the support.

The method of adding the matting agent used in the present invention may be a method in which the matting agent is dispersed in a coating solution in advance, or may be sprayed after the coating solution is applied and before the drying is completed. May be used. When a plurality of types of matting agents are added, both methods may be used in combination.

In the present invention, a conductive compound such as a metal oxide and / or a conductive polymer can be contained in the constituent layer in order to improve the chargeability. These may be contained in any layer, but are preferably contained in an undercoat layer, a backing layer, a layer between the photosensitive layer and the undercoat, and the like.

In the present invention, US Pat. No. 5,244,
The conductive compounds described in No. 773 columns 14 to 20 are preferably used.

Various additives may be added to any of the photosensitive layer, the non-photosensitive layer, and other constituent layers. In the photothermographic material of the present invention, for example, a surfactant, an antioxidant, a stabilizer, a plasticizer, an ultraviolet absorber, a coating aid, and the like may be used in addition to the above. These additives and the other additives mentioned above are used in Research Disclosure.
re Item 17029 (June 1978, p. 9-
The compound described in 15) can be preferably used.

Binders suitable for the photothermographic material of the present invention are transparent or translucent, generally colorless, and include natural polymer synthetic resins, polymers and copolymers, and other film-forming media such as gelatin, gum arabic,
Poly (vinyl alcohol), hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, poly (vinyl pyrrolidone), casein, starch, poly (acrylic acid), poly (methyl methacrylic acid), poly (vinyl chloride), poly (methacrylic acid) ), Copoly (styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinyl acetal) s (eg, poly (vinyl formal) and poly (vinyl butyral)), poly (ester) ), Poly (urethane), phenoxy resin, poly (vinylidene chloride), poly (epoxide),
Poly (carbonate) s, poly (vinyl acetate),
There are cellulose esters and poly (amides). It may be hydrophilic or non-hydrophilic. In order to protect the surface of the light-sensitive material and prevent abrasion, a non-light-sensitive layer may be provided outside the light-sensitive layer. The binder used for these non-photosensitive layers may be the same as or different from the binder used for the photosensitive layers.

In the present invention, in order to increase the speed of thermal development, the amount of the binder in the photosensitive layer is 1.5 to 10 g / m ^2.
It is preferred that More preferably, 1.7 to 8 g
/ M ² .

The support used in the present invention may be a plastic film (for example, polyethylene terephthalate, polycarbonate,
Polyimide, nylon, cellulose triacetate, polyethylene naphthalate) are preferred.

Among them, a preferred support is a support of polyethylene terephthalate (hereinafter abbreviated as PET) and a plastic (hereinafter abbreviated as SPS) containing a styrene-based polymer having a syndiotactic structure. The thickness of the support is about 50 to 300 μm, preferably 70 to 180 μm.

A plastic support which has been heat-treated can also be used. The plastics to be employed include the above-mentioned plastics. The heat treatment of the support means that after forming these supports and before the photosensitive layer is applied, at a temperature higher than the glass transition point of the support by 30 ° C. or more,
Preferably at a temperature higher than 35 ° C., more preferably 40 ° C.
It is preferable to heat at a temperature higher than ℃. However, the effect of the present invention cannot be obtained by heating at a temperature exceeding the melting point of the support.

Next, the plastic used will be described.

PET is composed of polyethylene terephthalate in all of the polyester components. In addition to polyethylene terephthalate, terephthalic acid, naphthalene-2,6-dicarboxylic acid, isophthalic acid, butylene dicarboxylic acid and 5-sodium sulfo acid are used as acid components. A polyester containing a modified polyester component of isophthalic acid, adipic acid or the like and a glycol component such as ethylene glycol, propylene glycol, butanediol, cyclohexanedimethanol or the like in an amount of 10 mol% or less of the entire polyester may be used.

SPS is a polystyrene having steric regularity unlike ordinary polystyrene (atactic polystyrene). The regular stereoregular structure part of SPS is called a racemo chain, and it is preferable that there are more regular parts such as two, three, five or more. In the present invention, the racemo chain is 2 It is preferably 85% or more in the chain, 75% or more in the three chains, 50% or more in the five chains, and 30% or more in the further chains. The polymerization of SPS can be carried out according to the method described in JP-A-3-131843.

As the method of forming a support and the method of producing an undercoat used in the present invention, known methods can be used. Preferably, the method described in paragraph [0030] of JP-A-9-50094 is used.
To [0070].

The photothermographic material of the present invention, which forms a photographic image by a heat development process, comprises a reducible silver source (organic silver salt), a photosensitive silver halide, a reducing agent and, if necessary, silver. It is preferable that the photothermographic material contains a color toning agent which suppresses the color tone of the present invention in a state of being usually dispersed in an (organic) binder matrix. The photothermographic material of the present invention is stable at room temperature, but is exposed to a high temperature (for example, 80 ° C. to 14 ° C.).
(0 ° C.). Heating generates silver through an oxidation-reduction reaction between an organic silver salt (functioning as an oxidizing agent) and a reducing agent. This oxidation-reduction reaction is accelerated by the catalytic action of the latent image generated on the silver halide upon exposure. The silver formed by the reaction of the organic silver salt in the exposed areas provides a black image, which contrasts with the unexposed areas, resulting in the formation of an image. This reaction process proceeds without supplying a processing liquid such as water from the outside.

The photothermographic material of the present invention has at least one photosensitive layer on a support. Although only a photosensitive layer may be formed on the support, it is preferable to form at least one non-photosensitive layer on the photosensitive layer. To control the amount or wavelength distribution of light passing through the photosensitive layer, a filter dye layer on the same side as the photosensitive layer and / or an antihalation dye layer, a so-called backing layer, may be formed on the opposite side. A dye or pigment may be included in the active layer. As the dye to be used, any compound may be used as long as it has a desired absorption in a desired wavelength range, and examples thereof include JP-A-59-6481 and JP-A-59-1.
No. 82436, U.S. Pat. No. 4,271,263, U.S. Pat. No. 4,594,312, European Patent Publication 533,0
08, European Patent Publication 652,473, JP-A-2-2-2
No. 16140, JP-A-4-348339, JP-A-7-
Compounds described in JP-A-191432 and JP-A-7-301890 are preferably used.

These non-photosensitive layers preferably contain the above-mentioned binder and matting agent, and may further contain a slip agent such as a polysiloxane compound, wax or liquid paraffin.

The light-sensitive layer may be composed of a plurality of layers, and the sensitivity may be changed to a high-sensitivity layer / low-sensitivity layer or a low-sensitivity layer / high-sensitivity layer for adjusting the gradation.

Details of the photothermographic material are described in, for example, US Pat. Nos. 3,152,904 and 3,457,0
No. 75; Morgan (Dry Silver Pho)
Graphic Material) "and D.C. Morgan and B.A. "The Silver System Treated by Heat (Therma)" by Shelly
llly Processed SilverSystem
ms) "(Imaging Processes and Materials
nd Materials) Neblette No. 8
Plate, Sturge, V.S. Walworth, A .; Shepp, 2nd page, 1969) and the like. Among them, the present invention is characterized in that an image is formed by thermally developing a photosensitive material at 80 to 140 ° C., and no fixing is performed. Therefore, the silver halide and the organic silver salt remaining in the unexposed area remain in the photosensitive material without being removed.

In the present invention, after the heat development processing,
The optical transmission density of the light-sensitive material containing the support at 400 nm is preferably 0.2 or less. A more preferable value of the optical transmission density is 0.02 or more and 0.2 or less.

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

[0100]

EXAMPLES Example 1 << Preparation of PET-undercoated photographic support >> A corona discharge treatment of 8 w / m ² · min was applied to both surfaces of a commercially available biaxially stretched and heat-fixed 100 μm thick PET film. On one surface, the following undercoating coating solution a-1 is applied so as to have a dry film thickness of 0.8 μm and dried to form an undercoating layer A-1. Liquid b-1 was dried to a thickness of 0.8 μm.
m and dried to form an antistatic subbing layer B
It was set to -1.

<< Undercoat Coating Solution a-1 >> Butyl acrylate (30% by weight) t-butyl acrylate (20% by weight) Styrene (25% by weight) 2-hydroxyethyl acrylate (25% by weight) copolymer latex liquid (Solid content 30%) 270 g (C-1) 0.6 g Hexamethylene-1,6-bis (ethylene urea) 0.8 g Finished to 1 liter with water.

<< Undercoat Coating Solution b-1 >> Butyl acrylate (40% by weight) Styrene (20% by weight) Glycidyl acrylate (40% by weight) copolymer latex liquid (solid content 30%) 270 g (C-1) 0.6 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 surface of the undercoating layer A-1, and the undercoating upper layer coating solution a-2 shown below is coated on the undercoating layer A-1 to a dry film thickness of 0.1 μm. Sublayer B as Layer A-2
-1 is coated with the following undercoating layer coating solution b-2 having a dry film thickness of 0.
Coating was performed as a subbing upper layer B-2 having an antistatic function so as to have a thickness of 8 μm.

<< Undercoating upper layer coating liquid a-2 >> Gelatin 0.4 g / m ² Weight (C-1) 0.2 g (C-2) 0.2 g (C-3) 0.1 g Silica particles ( (Average particle size: 3 μm) 0.1 g Finish to 1 liter with water.

<< Lower Coating Upper Layer Coating Solution b-2 >> (C-4) 60 g Latex liquid containing (C-5) as a component (solid content: 20%) 80 g Ammonium sulfate 0.5 g (C-6) 12 g Polyethylene glycol ( (Weight average molecular weight: 600) 6 g Finished to 1 liter with water.

[0106]

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[0107]

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<< Heat Treatment of Support >> In the above-mentioned undercoat drying step of the undercoated support, the support was heated at 140 ° C.
Thereafter, it was gradually cooled.

<< Preparation of Silver Halide Emulsion A >> Water 900m
7.5 g of inert gelatin and 10 ml of potassium bromide
mg, and adjusted to a temperature of 35 ° C. and a pH of 3.0.
An aqueous solution containing potassium bromide and potassium iodide (equimolar amounts to the above silver nitrate) in a molar ratio of 2) and K ₂ [Ir (NO) C
l ₅ a 1 × 10 ^-6 mol, and rhodium chloride salt per mole of silver of 1 × 10 ^-4 mol per mol of silver a], pAg 7.7
, And added by a controlled double jet method. Thereafter, 4-hydroxy-6-methyl-1,3,3
a, 7-Tetrazaindene was added and the pH was adjusted to 5 with NaOH.
Adjusted to an average particle size of 0.06 μm and a monodispersity of 10
% Projection diameter area variation coefficient 8%, [100] face ratio 8
7% of cubic silver iodobromide grains were obtained. This emulsion was subjected to coagulation sedimentation using a gelatin coagulant, and after desalting, 0.1 g of phenoxyethanol was added to adjust the pH to 5.9 and the pAg to 7.5 to obtain a silver halide emulsion A. Further, chemical sensitization was performed with chloroauric acid and inorganic sulfur.

<< Preparation of Sodium Salt Solution of Fatty Acid >> 94
8. 32.4 g of behenic acid and arachidic acid in 5 ml of pure water.
9 g and stearic acid 5.6 g were dissolved at 90 ° C. Next, 98 ml of a 1.5 M aqueous sodium hydroxide solution was added while stirring at a high speed. Next, after adding 0.93 ml of concentrated nitric acid, the mixture was cooled to 55 ° C. and stirred for 30 minutes to obtain a sodium salt solution of a fatty acid.

<< Preparation of Preform Emulsion of Fatty Acid Silver Salt and Silver Halide Emulsion A >> 15.1 g of the silver halide emulsion A was added to the above fatty acid sodium salt solution, and the pH was adjusted to 8.1 with a sodium hydroxide solution. Thereafter, 147 ml of a 1M silver nitrate solution was added over 7 minutes, the mixture was further stirred for 20 minutes, and ultrafiltration was performed to remove water-soluble salts. The resulting silver behenate was grains having an average grain size of 0.8 μm and a monodispersity of 8%. After the floc of the dispersion was formed, water was removed, washed with water six times, and dried to obtain a preform emulsion.

<< Preparation of Photosensitive Emulsion >> A solution of polyvinyl butyral (average molecular weight: 3000) in 2-butanone (MEK) (1.7 watts) was added to 100 g of the resulting preform emulsion.
(t%) 544 g and toluene 107 g were gradually added and mixed, and then dispersed using a high-pressure homogenizer (Nanomizer LA: manufactured by Nanomizer Co., Ltd.) of a type in which the dispersion liquids collide with each other. Dispersion was performed using an apparatus having a high-pressure pulverizing section as shown in FIG. 1 (Microfluidizer (manufactured by Mizuho Industry Co., Ltd.)). (Gaulin Homogenizer (APV))
The dispersion obtained by using the above was used as photosensitive emulsion 3 of the present invention, and the dispersion conditions were 560 kgf / cm ² 2p for all three samples.
ass.

The following layers were sequentially formed on the support,
A photothermographic material was prepared. The drying was performed at 60 ° C for 1 hour.
Performed in 5 minutes.

Back side coating: A solution having the following composition was applied.

Cellulose acetate (10% 2-butanone (MEK) solution) 15 ml / m ² dye-B 7 mg / m ² dye-C 7 mg / m ² Matting agent: monodispersity 15%, average particle size 10 μm Monodispersed silica 30 mg / m ² C ₉ H ₁₉ —C ₆ H ₄ —SO ₃ Na 10 mg / m ²

[0116]

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Photosensitive layer side coating Photosensitive layer 1: A solution having the following composition was coated and the silver amount was 2.1 g / m ^2.
It was applied so that it became.

Photosensitive emulsion shown in Table 1 240 g Sensitizing dye-1 (0.1% methanol solution) 1.7 ml Pyridinium bromide perbromide (6% methanol solution) 3 ml Calcium bromide (0.1% methanol solution) 1 0.7 ml Antifoggant-2 (10% methanol solution) 1.2 ml 2- (4-chlorobenzoylbenzoic acid (12% methanol solution) 9.2 ml 2-mercaptobenzimidazole (1% methanol solution) 11 ml tribromomethylsulfo Quinoline (5% methanol solution) 17 ml Reducing agent A-4 (20% methanol solution) 29.5 ml Hardening agent H (1% methanol solution) 3 ml

[0119]

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[0120]

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Surface protective layer: A solution having the following composition was applied on the photosensitive layer.

Acetone 35 ml / m ² Methyl ethyl ketone 17 ml / m ² Cellulose acetate 2.3 g / m ² Methanol 7 ml / m ² Phthalazine 250 mg / m ² 4-Methylphthalic acid 180 mg / m ² Tetrachlorophthalic acid 150 mg / m ² Tetrachlorophthale Acid anhydride 170 mg / m ² Matting agent: Monodispersity 10% Monodisperse silica having an average particle size of 4 μm 70 mg / m ² C ₉ H ₁₉ —C ₆ H ₄ —SO ₃ Na 10 mg / m ² << Organic silver salt dispersion Particle Size and Particle Size Distribution Evaluation> Laser Diffraction / Scattering Type Particle Size Distribution Meter (manufactured by HORIBA, LA-920)
The size of the organic silver salt particles in the photosensitive emulsion and the frequency of particles having a particle size of 10 μm or more were measured by using the mold. The measurement conditions were as follows: the dispersion was diluted with 2-butanone (MEK), and the measurement was performed with stirring in a batch cell system. Here, the average particle size means a cubic equivalent median size.

<< Exposure and Development Processing >> The photothermographic material prepared as described above was exposed with an imager having a semiconductor laser of 810 nm. Thereafter, heat development was performed at 110 ° C. for 15 seconds using an automatic developing machine having a heat drum.
At that time, exposure and development were performed in a room conditioned at 23 ° C. and 50% RH. The sensitivity was expressed as a relative value when the comparison was set to 100.

<< Evaluation of Fog Density After Thermal Development >> The photothermographic material prepared above was divided into two parts.
% For 5 days, and the fog density was measured. The fog density referred to here is the density of a portion where a halftone dot is exposed to 0%. The smaller the fog density, the more practically preferable.

[0125]

[Table 1]

From the results in Table 1, it can be seen that the organic silver salt dispersion used in the preparation of Comparative Sample 1 has an average particle size of 3.24 μm, indicating a reasonable dispersibility, but the frequency of particles having a particle size of 10 μm or more is 2%. It can be seen that the particle size distribution of the organic silver salt particles is wide. The exposed and developed comparative sample 1 has high fog,
Also, the sensitivity is not enough.

On the other hand, in Samples 2 and 3 produced by the production method of the present invention, an organic silver salt dispersion having improved organic silver salt dispersibility and a narrow particle size distribution of organic silver salt particles was obtained. Obviously, it is clear that the fog after exposure and development processing is low and the sensitivity is improved.

[0128]

According to the present invention, a method for producing an organic silver salt dispersion having an improved dispersibility of the organic silver salt and a narrow particle size distribution of the organic silver salt particles, and a fog produced by the production method. And a photothermographic material having high sensitivity and a high sensitivity could be provided.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a high-pressure pulverizing section of a dispersing apparatus used in the production method of the present invention.

FIG. 2 is a diagram illustrating a high-pressure pulverizing section of a dispersing apparatus used in the production method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High-pressure grinding part 2 High-pressure grinding part 3 High-pressure grinding part 4 High-pressure grinding part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H123 AB01 AB15 BA01 BC00 CA22 DA06 EA00 FA02 4G065 AA01 AA06 AA07 AB01X AB01Y AB02Y AB03Y AB12X AB12Y AB29Y AB30X BA07 BA20 BB06 CA11 DA09 EA10 FA01 FA02 4H048 AA52 VA20 AB05

Claims (2)

[Claims] 1. A high-speed flow is generated by applying pressure to a raw material liquid comprising at least an organic silver salt and a solvent, and the organic silver salt is dispersed by passing the high-speed flow through a high-pressure pulverizing section. Of producing an organic silver salt dispersion. 2. A photothermographic material comprising an organic silver salt dispersion prepared by the method according to claim 1.