JPH1062899A - Heat-developable photosensitive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a heat-developable photosensitive material having a photosensitive layer formed by coating with a coating material using an aqueous solvent advantageous from the view points of environmental protection and cost and low in fog even in the case of being used and stored in an atmosphere of high humidity by using a polymer specified in the equilibrium water content for the main binder of the photosensitive layer and using the coating material comprising a specified amount of solvent and water in the total residual amount. SOLUTION: The main binder of the photosensitive layer of this heat- developable photosensitive material is the polymer having an equilibrium water content of <=2weight% at 25 deg.C in 60% relative humidity, and the photosensitive layer is formed by using a coating material comprising the solvent and water occupying >=30% of the solvent. The usable resin is an acrylic and polyester resins and the water-miscible organic solvent can be embodied by alcohols, such as methyl and ethyl alcohols, cellosolves, such as methylcellosolve, and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photothermographic material for forming an image by thermal development (hereinafter also referred to as "sensitive material"), and more particularly, to a photosensitive layer coated by using an amount of an aqueous solution. And a photothermographic material having low fog even when stored in a high humidity atmosphere.

[0002]

2. Description of the Related Art There are many known photosensitive materials having a photosensitive layer on a support and forming an image by exposing the image. Among them, a technology for forming an image by thermal development is one of the systems that can protect the environment and simplify the image forming means.

A method of forming an image by thermal development is described in, for example, US Pat. Nos. 3,152,904 and 3,457,075.
And D. Morgan and B.A. Shely
"Thermal Processed Silver System (Thermally
Processed Silver Systems ”(Imaging Processesan and Materials)
d Materials) Neblette 8th edition, Sturge,
V. Walworth, A .; Shep
p) Compilation, page 2, 1969). Such photosensitive materials comprise a reducible non-photosensitive silver source (eg, an organic silver salt), a catalytically active amount of a photocatalyst (eg, silver halide), and a silver reducing agent dispersed in a conventional (organic) binder matrix. It is contained in a state where it is used. The photosensitive material is stable at normal temperature, but when heated to a high temperature (for example, 80 ° C. or higher) after exposure, silver is reduced through a redox reaction between a reducible silver source (which functions as an oxidizing agent) and a reducing agent. Generate This oxidation-reduction reaction is promoted by the catalytic action of the latent image generated by the exposure. The silver formed by the reaction of the reducible silver salt in the exposed areas provides a black image, which contrasts with the unexposed areas, resulting in the formation of an image.

A photosensitive material for forming an image by such thermal development (heat-developable photosensitive material) meets requirements for simplification of processing and environmental preservation, which have been increasing in recent years.

Conventionally, heat-developable light-sensitive materials of this type have been known, but most of these light-sensitive materials are prepared by applying a coating solution using an organic solvent such as toluene, methyl ethyl ketone, (HEK) or methanol as a solvent. A photosensitive layer is formed. The use of an organic solvent as a solvent is disadvantageous not only in adverse effects on the human body in the manufacturing process but also in cost due to recovery of the solvent and the like.

Therefore, a method of forming a photosensitive layer (hereinafter also referred to as "aqueous photosensitive layer") using a coating solution of a water solvent which does not have such a concern has been considered. For example, JP-A-49-5
No. 2626, JP-A-53-116144 and the like describe examples using gelatin as a binder. JP-A-50-151138 discloses an example in which polyvinyl alcohol is used as a binder.

Japanese Patent Application Laid-Open No. 60-61747 discloses an example in which gelatin and polyvinyl alcohol are used in combination. As another example, JP-A-58-28737 describes an example of a photosensitive layer using water-soluble polyvinyl acetal as a binder.

Certainly, when such a binder is used, the photosensitive layer can be formed using a coating solution of an aqueous solvent, and the advantages in terms of environment and cost are great.

However, when a polymer such as gelatin, polyvinyl alcohol, or water-soluble polyacetal is used as a binder, there has been a disadvantage that fog of a photosensitive material becomes large when stored for a long time under high humidity.

Therefore, there has been a demand for a technique for suppressing fog when stored in a high-humidity atmosphere using an aqueous photosensitive layer that is advantageous in terms of environment and cost.

[0011]

The problem to be solved by the present invention is to form a photosensitive layer by applying a coating solution of a water solvent which is advantageous in terms of environmental protection and cost, and to provide a high humidity atmosphere. An object of the present invention is to provide a photothermographic material having low fog even when used or stored under the following conditions.

[0012]

The above objects can be achieved by the present invention described below. (1) A photothermographic material comprising a photosensitive layer containing a photosensitive silver halide on at least one surface of a support, and containing a non-photosensitive silver salt and a reducing agent for the non-photosensitive silver salt. The main binder of the photosensitive layer is a polymer having an equilibrium water content of 2% by weight or less at 25 ° C. and 60% RH, and the photosensitive layer is coated with a coating solution containing 30% by weight or more of water as a solvent and dried. A photothermographic material characterized by being formed. (2) The photothermographic material according to the above (1), wherein the non-photosensitive silver salt is an organic silver salt. (3) The photothermographic material according to the above (1) or (2), wherein the main binder of the photosensitive layer is a polymer dispersed in an aqueous solvent. (4) The photothermographic material according to any one of (1) to (3), wherein the photosensitive layer is formed using a coating solution in which 70% by weight or more of a solvent is water.

[0013]

Embodiments of the present invention will be described below in detail. The photothermographic material of the present invention has a photosensitive layer containing a photosensitive silver halide on at least one surface of a support. The binder for the photosensitive layer of the present invention (hereinafter referred to as “polymer of the present invention”). ) Is a polymer that is soluble or dispersible in an aqueous solvent (aqueous solvent) and has an equilibrium water content of 2% by weight or less at 25 ° C. and 60% RH.

The use of such a polymer makes it possible to coat a photosensitive layer using a water solvent containing 30% by weight or more of water as a coating solvent, which is advantageous in terms of environment and cost, and is particularly advantageous in terms of cost. The generation of fog due to storage in a humid atmosphere is suppressed. On the other hand, when the above equilibrium water content exceeds 2% by weight, fog due to storage in a high humidity atmosphere increases. In addition, application using an organic solvent is disadvantageous in terms of environment and cost as compared with the above-mentioned aqueous solvent.

The aqueous solvent in which the polymer of the present invention is soluble or dispersible is water or a mixture of water and 70% by weight or less of a water-miscible organic solvent. Examples of the water-miscible organic solvent include alcohols such as methyl alcohol, ethyl alcohol, and propyl alcohol; cellosolves such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve; ethyl acetate; and dimethylformamide.

Note that the term "aqueous solvent" is used herein even in a system in which the polymer is not thermodynamically dissolved but exists in a so-called dispersed state.

The term "equilibrium moisture content at 25 ° C. and 60% RH" used in the present invention refers to the weight W _{1 of} a polymer in a moisture-conditioning equilibrium in an atmosphere of 25 ° C. and 60% RH, and the weight of a polymer in an absolutely dry state at 25 ° C. Can be expressed as follows using the weight W ₀ of Equilibrium water content at 25 ° C. and 60% RH = ｛(W ₁ −W ₀ )
/ W ₀ ｝ × 100 (wt%) The actual measurement can be performed as shown in Examples below.

The polymer of the present invention is not particularly limited as long as it is soluble or dispersible in the above-mentioned aqueous solvent and has an equilibrium water content at 25 ° C. and 60% RH of 2% by weight or less. Among these polymers, polymers that can be dispersed in an aqueous solvent are particularly preferred. Examples of the dispersion state include a latex in which polymer solid fine particles are dispersed and a dispersion in which polymer molecules are dispersed in a molecular state or in the form of micelles.

The equilibrium water content of the polymer of the present invention at 25 ° C. and 60% RH needs to be 2 wt% or less.
Preferably, the content is 0.01 wt% or more and 1.5 wt% or less, and more preferably 0.02 wt% or more and 1 wt% or less.

Examples of the polymer of the present invention include acrylic resins, polyester resins, polyurethane resins, vinyl chloride resins, vinylidene chloride resins, and rubber resins (for example, S-based resins).
(BR resin and NBR resin), vinyl acetate resin, polyolefin resin, polyvinyl acetal resin and the like.

The polymer may be a homopolymer obtained by polymerizing a single monomer or a copolymer obtained by polymerizing two or more kinds of polymers. The polymer may be a linear or branched polymer. Further, the polymers may be crosslinked.

As the molecular weight of the polymer, the weight average molecular weight Mw is 1,000 to 1,000,000, preferably 3,000.
~ 500,000 is desirable. Those having a molecular weight of less than 1000 generally have low film strength after coating, and may cause inconveniences such as cracks in the photosensitive layer.

The following are specific examples of the polymer of the main binder of the photosensitive layer of the present invention. _{P-1 - (MMA) 50} - (EA) 45 - (AA) 5 - latex (Mw = 3 million in) P-2 - (2EHA) 30 - (MMA) 50 - (St) 15
- (MAA) ₅ - latex (Mw = 5 million in) P-3 - (BR) 50 - (St) 47 - (AA) 3 - latex (Mw = 1 million in) P-4 - (BR) 40 - (DVB) _10- (St) _45-
(MAA) ₅ - latex (Mw = 5 million in) P-5 - (VC) 70 - (MMA) 25 - (AA) 5 - latex (Mw = 1.5 million in) P-6 - (VDC) 60 − (MMA) ₃₀ − (EA) ₅ −
(MAA) _5- latex (Mw = 80,000)

In the above, abbreviations represent structural units derived from the following monomers, and the numerical values are wt%.

MMA: methyl methacrylate, EA: ethyl acrylate, AA: acrylic acid, 2EHA: 2-
Ethylhexyl acrylate, St: styrene, MA
A: methacrylic acid, BR: butadiene, DVB: divinylbenzene, VC: vinyl chloride, VDC: vinylidene chloride

Such a polymer is commercially available, and the following can be used.

For example, as the acrylic resin, Sebian A
−4635, 46583, 4601 (all manufactured by Daicel Chemical Industries, Ltd.), Nipol LX811, 814, 8
As polyester resins such as 20, 821, 857 (all manufactured by Zeon Corporation), FINETEX ES
650, 611, 679, 675, 525, 801, 8
50 (all manufactured by Dainippon Ink and Chemicals, Inc.), WDsize
Examples of polyurethane resins such as WHS (manufactured by Eastman Chemical) include HYDRAN AP10, 20, 3
0, 40, 101H, HYDRAN HW301, 31
Examples of vinylidene chloride resins such as L.0, 350 (all manufactured by Dainippon Ink and Chemicals, Inc.) include L502, L513, L1
Examples of vinyl chloride resins such as 23c, L106c, L111 and L114 (all manufactured by Asahi Kasei Corporation) include G35
Examples of polyolefin resins such as 1, G576 (all manufactured by Nippon Zeon Co., Ltd.) include Chemipearl S-120, S-3
00, SA-100, A-100, V-100, V-2
00 and V-300 (all manufactured by Mitsui Petrochemical Co., Ltd.).

In the binder of the present invention, these polymers may be used alone or as a blend of two or more.

The above-mentioned polymer is used as a main binder in the photosensitive layer of the present invention. The term "main binder" as used herein means "a state in which the above polymer accounts for 70% by weight or more of all binders in the photosensitive layer". The content is more preferably 80% by weight or more, and it is also preferable to use only the polymer of the present invention. When two or more types are used, the total amount is used.

Therefore, the photosensitive layer of the present invention has a temperature of 25.degree.
Polymers with an equilibrium water content of more than 2 wt% at% RH
The binder may be contained in an amount of not more than 30% by weight, particularly less than 30% by weight, more preferably not more than 20% by weight. Preferred examples of these polymers include gelatin, polyvinyl alcohol, and the like.

By using the polymer of the present invention in the above ratio in the photosensitive layer of the present invention, the equilibrium water content of the polymer mixture at 25 ° C. and 60% RH is 2 wt% or less.

The amount of the binder in the photosensitive layer of the present invention is 5: 5 by weight in terms of the ratio of the binder to the photosensitive silver halide.
It is preferably 1-1500: 1, more preferably 10: 1-800: 1. The ratio of the binder to the non-photosensitive silver salt is preferably 15: 1 to 1: 2, more preferably 8: 1 to 1: 1.

In the present invention, the photosensitive layer is formed using a coating solution, and the solvent for the coating solution is 30 wt% water.
It is a water solvent containing the above, and may contain a water-miscible organic solvent as described above in addition to water. Examples of a preferable water solvent include water (100), a water / methanol system, for example, water (90) ) / Methanol (10), water (70) / methanol (30), water (60) / methanol (40), water (40) / methanol (60), water / methanol / isopropyl alcohol system, for example, water (80) / Methanol (10) / isopropyl alcohol (10), water / dimethylformamide, for example, water (95) / dimethylformamide (5), water / ethyl acetate, for example, water (96)
/ Ethyl acetate (4), water / ethanol / butyl cellosolve system, for example, water (80) / methanol (10) / butyl cellosolve (10), etc.
wt%). Among them, a solvent containing 70% by weight or more of water is preferable.

The light-sensitive layer of the light-sensitive material of the present invention is a layer containing light-sensitive silver halide grains.

If necessary, this layer may contain a non-photosensitive silver salt or a reducing agent for a silver salt. The non-photosensitive silver salt is preferably contained in the photosensitive layer.

Further, a crosslinking agent such as an epoxy compound or a melamine compound, a dye, a filler such as colloidal silica, an anionic, nonionic, cationic or betaine surfactant may be contained.

The photosensitive material of the present invention may have a single photosensitive layer,
Two or more layers may be used. The photosensitive layer may be on one side or both sides of the support. When two or more photosensitive layers are present, at least one layer uses the polymer of the present invention,
The photosensitive layer according to the present invention may be any one coated with a water solvent as a coating solvent, but is preferably all the photosensitive layer according to the present invention.

The thickness of the photosensitive layer of the light-sensitive material of the present invention is preferably in the range of 0.2 to 30 μm, more preferably 1 to 20 μm per layer.

Such a photosensitive layer is formed by using a coating solution containing components according to the composition of the photosensitive layer and an aqueous solvent of a coating solvent. The components (solid content) in the coating solution and the aqueous solvent are used. Is usually 1/99 to 20 by weight of the component / water solvent.
About / 80. Drying after application is 30 ~ 200 ℃ 3
It may be performed for about 0 seconds to 10 minutes. The photosensitive layer can be applied separately from other layers such as a surface protective layer, or can be applied simultaneously as a multilayer.

The method of forming the photosensitive silver halide in the present invention is well known in the art, and uses, for example, the methods described in Research Disclosure No. 17029, June 1978, and US Pat. No. 3,700,458. be able to. Specific methods that can be used in the present invention include a method of converting a part of the silver of the organic silver salt to a photosensitive silver halide by adding a halogen-containing compound to the prepared organic silver salt, gelatin. Alternatively, a method of preparing a photosensitive silver halide grain by adding a silver supply compound and a halogen supply compound to another polymer solution and mixing the resultant with an organic silver salt can be used. In the present invention, the latter method can be preferably used. The grain size of the photosensitive silver halide is preferably small for the purpose of suppressing white turbidity after image formation, specifically, 0.20 μm or less, more preferably 0.01 μm or more and 0.15 μm or less, and still more preferably. Is preferably 0.02 μm or more and 0.12 μm or less. Here, the grain size means the length of the edge of the silver halide grain when the silver halide grain is a cubic or octahedral so-called normal crystal. In the case where the silver halide grains are tabular grains, the diameter refers to a diameter when converted into a circular image having the same area as the projected area of the main surface. In the case of other than normal crystals, for example, in the case of spherical grains, rod-shaped grains, etc., it refers to the diameter of a sphere equivalent to the volume of silver halide grains.

The shape of the silver halide grains is cubic,
Octahedral, tabular particles, spherical particles, rod-like particles, potato-like particles and the like can be mentioned, and in the present invention, cubic particles and tabular particles are particularly preferable. When tabular silver halide grains are used, the average aspect ratio is preferably 100: 1 to 2: 1, more preferably 50: 1 to 3:
1 is good. Further, grains having rounded corners of silver halide grains can also be preferably used. The surface index (mirror index) of the outer surface of the photosensitive silver halide grains is not particularly limited. However, the spectral sensitization efficiency when the spectral sensitizing dye is adsorbed is high. preferable. The ratio is preferably 50% or more.
% Or more, more preferably 80% or more. The ratio of the {100} plane of the Miller index is determined by the T.V. method utilizing the dependence of the adsorption of the sensitizing dye on the {111} plane and the {100} plane. Tani: J. et al. Imaging Sci. , 29,
165 (1985). The halogen composition of the photosensitive silver halide is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver bromide, silver iodobromide, silver iodochlorobromide, and silver iodide. In the present invention, silver bromide or silver iodobromide can be preferably used. Particularly preferred is silver iodobromide, and the silver iodide content is preferably from 0.1 mol% to 40 mol%, more preferably from 0.1 mol% to 20 mol%. The distribution of the halogen composition in the grains may be uniform, the halogen composition may be changed stepwise, or may be changed continuously, but as a preferred example, the silver iodide content inside the grains is High silver iodobromide grains can be used. Preferably, silver halide grains having a core / shell structure can be used. As the structure, core / shell particles having preferably a 2- to 5-layer structure, more preferably a 2- to 4-layer structure, can be used.

The photosensitive silver halide grains of the present invention preferably contain at least one complex of a metal selected from rhodium, rhenium, ruthenium, osmium, iridium, cobalt or iron. These metal complexes are 1
They may be of the same kind, or two or more kinds of complexes of the same metal and different metals may be used in combination. The preferred content is in the range of 1 × 10 ^-9 mol to 1 × 10 ^-2 mol per mol of silver,
The range of 1 × 10 ⁻⁸ mol to 1 × 10 ⁻⁴ is more preferable.
A specific structure of the metal complex is described in JP-A-7-22544.
A metal complex having a structure described in No. 9 or the like can be used. As the compound of cobalt and iron, a hexacyano metal complex can be preferably used. Specific examples are shown below.

[Fe (CN) ₆ ] ^4- [Fe (CN) ₆ ] ^3- [Co (CN) ₆ ] ^3-

The phase containing the metal complex in the silver halide may be uniform, may be contained in the core at a high concentration, or may be contained in the shell at a high concentration, and there is no particular limitation.

The photosensitive silver halide grains can be desalted by washing with a method known in the art such as a noodle method or a flocculation method. Good.

The photosensitive silver halide grains in the present invention are preferably chemically sensitized. As a preferred chemical sensitization method, a sulfur sensitization method, a selenium sensitization method, and a tellurium sensitization method are well known in the art. 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, and P = Te Compound having a bond, tellurocarboxylates, Te-organyl
Tellurocarboxylic acid esters, di (poly) tellurides,
Tellurides, tellurols, telluroacetals, tellurosulfonates, compounds having a P-Te bond, including T
e Heterocycles, tellurocarbonyl compounds, inorganic tellurium compounds, colloidal tellurium, and the like can be used. Compounds preferably used in the noble metal sensitization method are described, for example, in chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, gold selenide, and US Pat. No. 2,448,060 and British Patent No. 6,180,61. Compounds can be preferably used. Specific compounds of 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. it can. When the pH of the emulsion is 7 or more or pAg
Can be reduced and sensitized by keeping at 8.3 or less. Further, reduction sensitization can be achieved by introducing a single addition portion of silver ion during grain formation.

The photosensitive silver halide of the present invention is used in an amount of 0.0 mol of the photosensitive silver halide per mol of the organic silver salt.
It is preferably from 1 mol to 0.5 mol, more preferably from 0.02 mol to 0.3 mol, and particularly preferably from 0.03 mol to 0.25 mol. Regarding the mixing method and mixing conditions of the separately prepared photosensitive silver halide and organic silver salt, the prepared silver halide particles and organic silver salt are mixed with a high-speed stirrer, ball mill, sand mill, colloid mill, vibration mill, homogenizer, etc. There is a method of mixing, or a method of preparing an organic silver salt by mixing photosensitive silver halide prepared at any timing during the preparation of the organic silver salt, etc. There is no particular limitation as long as it appears.

The non-photosensitive silver salt which can be used in the present invention is relatively stable to light, but can be used in the presence of an exposed photocatalyst (such as a latent image of a photosensitive silver halide) and a reducing agent. , A silver salt that forms a silver image when heated to 80 ° C. or higher. The non-photosensitive silver salt is preferably an organic silver salt. The organic silver salt can be any organic substance including a source capable of reducing silver ions. Silver salts of organic acids, especially silver salts of long-chain fatty carboxylic acids (having 10 or more carbon atoms, more preferably 10 to 30, preferably 15 to 28) are preferred. Also preferred are organic or inorganic silver salt complexes in which the ligand has a complex stability constant in the range of 4.0 to 10.0. Preferred organic silver salts include silver salts of organic compounds having a carboxy group. Examples of these include, but are not limited to, silver salts of aliphatic carboxylic acids and silver salts of aromatic carboxylic acids. Preferred examples of the silver salt of an aliphatic carboxylic acid include silver behenate, silver stearate, silver oleate, silver laurate, silver caproate, silver myristate, silver palmitate, silver maleate, silver fumarate, and tartaric acid. Silver, silver linoleate, silver butyrate and silver camphorate, and mixtures thereof.

Silver salts of compounds containing a mercapto group or a thione group and derivatives thereof can also be used.
Preferred examples of these compounds include silver salts of 3-mercapto-4-phenyl-1,2,4-triazole,
Silver salt of mercaptobenzimidazole, silver salt of 2-mercapto-5-aminothiadiazole, silver salt of 2- (ethylglycolamide) benzothiazole, S-alkylthioglycolic acid (where the alkyl group has 12 carbon atoms)
-22), such as a silver salt of thioglycolic acid;
Silver salt of dithiocarboxylic acid such as silver salt of dithioacetic acid, silver salt of thioamide, silver salt of 5-carboxyl-1-methyl-2-phenyl-4-thiopyridine, silver salt of mercaptotriazine, and silver salt of 2-mercaptobenzoxazole Silver salt,
The silver salt described in U.S. Pat. No. 4,123,274, e.g.
Silver salts of 1,2,4-mercaptothiazole derivatives such as silver salts of amino-5-benzylthio-1,2,4-thiazole;
(Carboxyethyl) -4-methyl-4-thiazoline-2
-Silver salts of thione compounds such as silver salts of thione. Further, compounds containing an imino group can be used. Preferred examples of these compounds include silver salts of benzotriazole and derivatives thereof, for example, silver salts of benzotriazole such as silver methylbenzotriazole, silver salts of halogen-substituted benzotriazole such as silver 5-chlorobenzotriazole, and US Pat. No. 4,220,709, silver salts of 1,2,4-triazole or 1-H-tetrazole, and silver salts of imidazole and imidazole derivatives. For example, U.S. Pat.
Various silver acetylide compounds as described in Nos. 1 and 4775613 can also be used.

The shape of the organic silver salt that can be used in the present invention is not particularly limited, but a needle crystal having a short axis and a long axis is preferable. As is well known in photosensitive silver halide photosensitive materials, the inverse relationship between the size of silver salt crystal grains and their covering power is established in the photothermographic material of the present invention. When the size of the organic silver salt particles in the image forming section is large, it means that the covering power is small and the image density is low. Therefore, it is necessary to reduce the size of the organic silver salt. In the present invention, the minor axis is 0.01 μm or more and 0.20 μm or less, and the major axis is 0.10 μm.
m or more and 5.0 μm or less, short axis 0.01 μm or more and 0.15 μm or less, long axis 0.10 μm or more and 4.0 μm
The following is more preferred. The particle size distribution of the organic silver salt is preferably monodispersed. Monodispersion means that the percentage of the value obtained by dividing the standard deviation of the length of each of the minor axis and major axis by the minor axis and major axis is preferably 100% or less, more preferably 8%.
0% or less, more preferably 50% or less. The shape of the organic silver salt can be measured from a transmission electron microscope image of the organic silver salt dispersion. As another method for measuring the monodispersity, there is a method of obtaining the standard deviation of the volume-weighted average diameter of the organic silver salt, and the percentage variation coefficient of the value divided by the volume-weighted average diameter is preferably 100% or less, more preferably It is 80% or less, more preferably 50% or less. As a measuring method, for example, an organic silver salt dispersed in a liquid is irradiated with a laser beam, and the autocorrelation coefficient with respect to the time change of the fluctuation of the scattered light is obtained from the particle size (volume weight average diameter) obtained. be able to.

The addition amount of the non-photosensitive silver salt of the present invention is as follows.
It is expressed as the coating amount of the non-photosensitive silver salt per 1 m ² of the light-sensitive material.
1-20 g / m < ² >, More preferably, 1-15 g / m < ² > is desirable. Further, the silver coating amount in the photosensitive material of the present invention is preferably a photosensitive material 1 m ² per 0.05~15g in total.

The reducing agent for the non-photosensitive silver salt may be any substance which reduces silver ions to metallic silver, preferably an organic substance. Particularly, a hindered phenol reducing agent is preferred. The reducing agent should be present as 1 to 10% by weight of the imaging layer. When a reducing agent is added to a layer other than the photosensitive layer in a multi-layer structure, a slightly higher ratio of about 2 to 1 is used.
5% by weight tends to be more desirable.

A wide range of reducing agents have been disclosed for photothermographic materials utilizing non-photosensitive silver salts. For example, amide oximes such as phenylamidooxime, 2-thienylamidooxime and p-phenoxyphenylamidooxime; azines such as 4-hydroxy-3,5-dimethoxybenzaldehydeazine; 2,2′-bis (hydroxymethyl) propionyl A combination of an aliphatic carboxylic acid arylhydroazide and ascorbic acid such as a combination of β-phenylhydrazine and ascorbic acid; a combination of polyhydroxybenzene and hydroxylamine, reductone and / or hydrazine (for example, hydroquinone and bis ( Ethoxyethyl) hydroxylamine, piperidinohexose reductone or a combination of formyl-4-methylphenylhydrazine, etc.); phenylhydroxamic acid, p-hydroxyphenylhydroxa Acid and β- hydroxamic acids, such as aniline hydroxamic acid; combinations of azines and sulfonamidophenols (for example, phenothiazine and 2,6-dichloro-4-benzenesulfonamidophenol);
Ethyl-α-cyano-2-methylphenyl acetate,
Α-cyanophenylacetic acid derivatives such as ethyl-α-cyanophenylacetate; 2,2′-dihydroxy-1,
Bis-β-naphthol, as exemplified by 1′-binaphthyl, 6,6′-dibromo-2,2′-dihydroxy-1,1′-binaphthyl and bis (2-hydroxy-1-naphthyl) methane; bis -Β-naphthol and 1,3-
Combinations of dihydroxybenzene derivatives (such as 2,4-dihydroxybenzophenone or 2 ', 4'-dihydroxyacetophenone); 5-pyrazolones, such as 3-methyl-1-phenyl-5-pyrazolone; dimethylaminohexose reductone Reductones as exemplified by anhydrodihydroaminohexose reductone and anhydrodihydropiperidone hexose reductone; sulfonamides such as 2,6-dichloro-4-benzenesulfonamidophenol and p-benzenesulfonamidophenol Phenol reducing agents; 2-phenylindane-1,3-dione and the like; chromanes such as 2,2-dimethyl-7-tert-butyl-6-hydroxychroman; 2,6-dimethoxy-3,5-dicarbethoxy- 1,4-dihydro 1,4-dihydropyridines such as lysine; bisphenols (e.g., bis (2-hydroxy -3-t-butyl-5-methylphenyl) methane,
2,2-bis (4-hydroxy-3-methylphenyl)
Propane, 4,4-ethylidene-bis (2-t-butyl-6-methylphenol), 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane and 2 , 2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, etc.); ascorbic acid derivatives (eg, 1-ascorbyl palmitate, ascorbyl stearate, etc.); and aldehydes and ketones such as benzyl and biacetyl;
-Pyrazolidone and certain indan-1,3-diones.

In the present invention, it may be advantageous to include, in addition to the above components, additives known as "toning agents" which improve the image. Toning agents are disclosed in US Pat.
No. 54, No. 3847612 and No. 412328
As shown in No. 2, it is a material well known in the photographic art.

Examples of toning agents include phthalimide and N-hydroxyphthalimide; succinimide, pyrazoline-
5-one, and quinazolinone, 3-phenyl-2-
Cyclic imides such as pyrazolin-5-one, 1-phenylurazole, quinazoline and 2,4-thiazolidinedione; naphthalimides (e.g. N-hydroxy-
1,8-naphthalimide); cobalt complex (eg, cobalt hexamine trifluoroacetate); 3-mercapto-1,2,4-triazole, 2,4-dimercaptopyrimidine, 3-mercapto-4,5-diphenyl- Mercaptans exemplified by 1,2,4-triazole and 2,5-dimercapto-1,3,4-thiadiazole; N- (aminomethyl) aryldicarboximides [for example, (N, N-dimethylaminomethyl) phthalimide] And N, N- (dimethylaminomethyl) -naphthalene-2,3-dicarboximide); and blocked pyrazoles, isothiuronium derivatives and certain photobleaching agents (e.g., N, N'-hexamethylenebis (1- Carbamoyl-3,5-dimethylpyrazole),
1,8- (3,6-diazaoctane) bis (isothiuronium trifluoroacetate) and 2-tribromomethylsulfonyl)-(benzothiazole)]; and 3-ethyl-5 [(3-ethyl-2-benzo Thiazolinylidene) -1-methylethylidene] -2-thio-2,
4-oxazolidinedione; phthalazinone, phthalazinone derivative or metal salt, or 4- (1-naphthyl)
Phthalazinone, 6-chlorophthalazinone, 5,7-dimethoxyphthalazinone and 2,3-dihydro-1,4-
Derivatives such as phthalazinedione; phthalazinone and phthalic acid derivatives (for example, phthalic acid, 4-methylphthalic acid,
Phthalazine, a phthalazine derivative or a metal salt, or 4- (1-naphthyl) phthalazine, 6
Derivatives such as -chlorophthalazine, 5,7-dimethoxyphthalazine and 2,3-dihydrophthalazine; phthalazine and phthalic acid derivatives such as phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride Quinazolinedione, benzoxazine or naphthoxazine derivatives; rhodium complexes which function not only as color tone regulators but also in-situ as sources of halide ions for silver halide formation, such as hexachlororhodium (III) Ammonium, rhodium bromide, rhodium nitrate and hexachlororhodium (II
I) potassium acid and the like; inorganic peroxides and persulfates, such as ammonium disulfide and hydrogen peroxide;
Benzoxazines such as 1,3-benzoxazine-2,4-dione, 8-methyl-1,3-benzoxazine-2,4-dione and 6-nitro-1,3-benzoxazine-2,4-dione Pyrimidine and asymmetric-triazines (eg, 2,4-dihydroxypyrimidine, 2-hydroxy-4-aminopyrimidine, etc.), azauracil, and tetraazapentalene derivatives (eg, 3,6-dimercapto) -1,4-diphenyl-1H, 4H-2,3a, 5,6a-tetraazapentalene and 1,4-di (o-chlorophenyl)
-3,6-dimercapto-1H, 4H-2,3a, 5
6a-tetraazapentalene) and the like. The amount of the color toning agent added is preferably 0.05 to 3 g, more preferably 0.5 to 1.5 g per 1 g of Ag.

As the sensitizing dye in the present invention, any dye can be used as long as it can spectrally sensitize the silver halide grains in a desired wavelength region when adsorbed on the silver halide grains.

As sensitizing dyes, cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, holo-holer cyanine dyes, styryl dyes, hemicyanine dyes, oxonol dyes, hemioxonol dyes and the like can be used.

Useful sensitizing dyes for use in the present invention are described, for example, in RESEARCH DISCLOSURE Item 17643 IV-A (December 1978).
p.23), and in the literature described or cited in Item 1831X, August 1979, p. 437.

In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of the light source of various laser imagers, scanners, imagesetters and plate making cameras can be advantageously selected.

As an example of spectral sensitization to red light, He-
For the Ne laser light source, see Japanese Patent Application Laid-Open No.
Compounds I-1 to I-38 described in JP-A No.
Compounds I-1 to I-35 described in No. 5322 and I-1 to I-34 described in JP-A-7-287338.
No. 55-3981 for compounds and LED light sources
Dyes 1 to 20 described in JP-A No. 8 (Kokai) No. 62-28434.
Compounds I-1 to I-37 described in No. 3 and compounds I-1 to I-34 described in JP-A-7-287338 are advantageously selected.

The silver halide grains are spectrally sensitized in any wavelength range from 750 to 1400 nm. Specifically, photosensitive silver halide is converted to cyanine, merocyanine,
Various known dyes, including styryl, hemicyanine, oxonol, hemioxonol and xanthene dyes, can be spectrally sensitized advantageously. Useful cyanine dyes are, for example, cyanine dyes having basic nuclei such as thiazoline nuclei, oxazoline nuclei, pyrroline nuclei, pyridine nuclei, oxazole nuclei, thiazole nuclei, selenazole nuclei and imidazole nuclei. Preferred useful merocyanine dyes include, in addition to the above basic nuclei, a thiohydantoin nucleus, a rhodanine nucleus, an oxazolidinedione nucleus, a thiazolinedione nucleus, a barbituric acid nucleus,
Also includes acidic nuclei such as thiazolinone nuclei, malononitrile nuclei and pyrazolone nuclei. Among the above-mentioned cyanine and merocyanine dyes, those having an imino group or a carboxyl group are particularly effective. For example, US Pat.
No. 279, No. 3,719,495, No. 3,877,943
Nos., British Patent Nos. 1466201 and 1469117
No. 14222057, Tokuhei 3-10391,
JP-B-6-52387, JP-A-5-341432,
The dye may be appropriately selected from known dyes as described in JP-A-6-194787 and JP-A-6-301141. A particularly preferred structure of the dye is a cyanine dye having a thioether bond.
2-58239, 3-13838, 3-13
No. 8642, No. 4-255840, No. 5-72659
Nos. 5-72661, 6-222491, 2
-230506, 6-258775, 6-31
No. 7868, No. 6-324425, Tokuyohei 7-500
No. 926, for example.

These sensitizing dyes may be used alone or in combination, and a combination of sensitizing dyes is often used particularly for supersensitization. Along with the sensitizing dye, the emulsion may contain a dye which does not itself have a spectral sensitizing effect or a substance which does not substantially absorb visible light and exhibits supersensitization.

Useful sensitizing dyes, combinations of dyes exhibiting supersensitization and substances exhibiting supersensitization are described in Research Disclosure, Vol. 176, 17643 (Dec. 1978).
Monthly) Page 23, IV, Section J, or the aforementioned Japanese Patent Publication No. 49
No. 25500, No. 43-4933, JP-A-59-1
Nos. 9032 and 59-192242.

The sensitizing dyes used in the present invention may be used in combination of two or more. To add sensitizing dyes to a silver halide emulsion, they may be directly dispersed in the emulsion,
Or water, methanol, ethanol, propanol,
Acetone, methyl cellosolve, 2,2,3,3-tetrafluoropropanol, 2,2,2-trifluoroethanol, 3-methoxy-1-propanol, 3-methoxy-1-butanol, 1-methoxy-2-propanol , N, N-dimethylformamide or the like, alone or in a mixed solvent, and added to the emulsion.

Further, as disclosed in US Pat. No. 3,469,987, a dye is dissolved in a volatile organic solvent, and this solution is dispersed in water or a hydrophilic colloid. Method of adding to the inside, Tokiko Sho 44-
No. 23389, No. 44-27555, No. 57-220
As disclosed in No. 91 or the like, a dye is dissolved in an acid,
A method in which this solution is added to an emulsion, or an acid or base is added to the emulsion as an aqueous solution in the presence of an acid or a base, US Pat.
A method of adding an aqueous solution or a colloidal dispersion in the presence of a surfactant to an emulsion as disclosed in, for example, 822135 and 4006025,
As disclosed in JP-A-53-102733 and JP-A-58-105141, a method of directly dispersing a dye in a hydrophilic colloid and adding the dispersion to an emulsion is disclosed in JP-A-51-74624. As disclosed, a method in which a dye is dissolved using a compound that causes a red shift, and this solution is added to an emulsion can also be used. Also, ultrasonic waves can be used for the solution.

The sensitizing dye used in the present invention may be added to the silver halide emulsion of the present invention at any stage of the emulsion preparation which has been found to be useful. For example, U.S. Pat.
No. 28960, No. 4183756, No. 42256
No. 66, JP-A-58-184142 and JP-A-60-196
As disclosed in the specification of No. 749 or the like, the stage before the step of forming silver halide grains and / or before desalting, the period during and / or after desalting and before the start of chemical ripening, As disclosed in the specification of JP-A-58-113920 and the like, at any time during the process immediately before or during chemical ripening, or after chemical ripening and before coating, before the emulsion is coated. May be added.
Also, U.S. Pat. No. 4,225,666,
As disclosed in the specification of No. 29 or the like, the same compound may be used alone or in combination with a compound having a heterogeneous structure, for example, during the particle formation step and during the chemical ripening step or after the completion of the chemical ripening, The compound may be added in portions such as before aging or during the process and after completion, or may be added by changing the kind of the compound to be added and the combination of compounds.

In the present invention, a mercapto compound, a disulfide compound and a thione compound are contained in order to suppress or accelerate development to control development, to improve spectral sensitization efficiency, to improve storage stability before and after development, and the like. 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 is an aromatic ring or a condensed aromatic ring having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms. Preferably, the heteroaromatic ring is benzimidazole, naphthimidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzoterzole, imidazole, oxazole,
Pyrazole, triazole, thiadiazole, tetrazole, triazine, pyrimidine, pyridazine, pyrazine, pyridine, purine, quinoline or quinazolinone. This heteroaromatic ring is, for example, a halogen (for example,
Br and Cl), hydroxy, amino, carboxy,
Alkyl (eg one or more carbon atoms, preferably 1
May also have a substituent selected from the group consisting of those having from 1 to 4 carbon atoms) and alkoxy (e.g., having at least one carbon atom, preferably having from 1 to 4 carbon atoms). Good. Examples of the mercapto-substituted heteroaromatic compound include 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-mercapto-5-methylbenzimidazole, 6-ethoxy-2-mercaptobenzothiazole, 2'-dithiobis-benzothiazole, 3-mercapto-1,2,4-triazole, 4,5-diphenyl-2-imidazolethiol, 2-mercaptoimidazole, 1-ethyl-2-mercaptobenzimidazole, 2-mercaptoquinoline , 8-mercaptopurine, 2-mercapto-4 (3H) -quinazolinone, 7-
Trifluoromethyl-4-quinolinethiol, 2,3
5,6-tetrachloro-4-pyridinethiol, 4-amino-6-hydroxy-2-mercaptopyrimidine monohydrate, 2-amino-5-mercapto-1,3,4
-Thiadiazole, 3-amino-5-mercapto-1,
2,4-triazole, 4-hydroxy-2-mercaptopyrimidine, 2-mercaptopyrimidine, 4,6-diamino-2-mercaptopyrimidine, 2-mercapto-
Examples include 4-methylpyrimidine hydrochloride, 3-mercapto-5-phenyl-1,2,4-triazole, 2-mercapto-4-phenyloxazole, and the like, but the invention is not limited thereto.

The addition amount of these mercapto compounds is preferably in the range of 0.001 to 1.0 mol per mol of silver in the emulsion layer, more preferably 0.01 to 0.3 mol per mol of silver. Is the amount of

The light-sensitive silver halide emulsions and / or non-light-sensitive silver salts of the present invention are further protected against additional fog formation by antifoggants, stabilizers and stabilizer precursors, and are stored in stock. It can be stabilized against a decrease in sensitivity in the medium. Suitable antifoggants, stabilizers and stabilizer precursors which can be used alone or in combination are the thiazonium salts described in U.S. Pat. Nos. 2,131,038 and 2,694,716, the thiazonium salts described in U.S. Pat. Nos. 2,886,437 and 2,444,605. , A mercury salt described in U.S. Pat. No. 2,728,663, a urazole described in U.S. Pat. No. 3,287,135, a sulfocatechol described in U.S. Pat. Indazole, US Patent No. 283
No. 9405, polyvalent metal salt described in US Pat.
No. 39, and U.S. Pat.
Palladium, platinum and gold salts described in 566263 and 2597915, US Pat. No. 4,108,665.
And the halogen-substituted organic compounds described in U.S. Patent Nos. 4,128,557 and 4,442,202.
No. 37079, No. 4138365 and No. 445
9350 and U.S. Pat.
And a phosphorus compound described in No. 11985.

The hydrazine derivative that can be used in the present invention will be described. In the present invention, Japanese Patent Application No. 6-479 is filed.
The compound of the general formula (I) described in No. 61 is used. Specifically, compounds represented by I-1 to I-53 described in the same specification are used.

The following hydrazine derivatives are also preferably used.

(Formula 1) described in JP-B-6-77138
And specifically the compounds described on pages 3 and 4 of the same publication. A compound represented by the general formula (I) described in JP-B-6-93082, specifically, pages 8 to 1 of the publication
Compounds 1 to 38 on page 8. JP-A-6-23049
A compound represented by the general formula (4), the general formula (5) or the general formula (6) described in No. 7;
Compounds 4-1 to 4-10 described on page 26, compounds 5-1 to 5-42 described on pages 28 to 36, and 39
6-1 to 6-7. Compounds represented by the general formulas (1) and (2) described in JP-A-6-289520, specifically from page 5 to
Compounds 1-1) to 1-17) and 2-
1). Compounds represented by (Chemical Formula 2) and (Chemical Formula 3) described in JP-A-6-313936, specifically, compounds described on pages 6 to 19 of the same. Compounds represented by (Chemical Formula 1) described in JP-A-6-313951, specifically, compounds described on pages 3 to 5 of the same. Compounds represented by formula (I) described in JP-A-7-5610, specifically, compounds I-1 to I-38 described on pages 5 to 10 of the same. Compounds represented by general formula (II) described in JP-A-7-77783, specifically, compounds described on pages 10 to 27 of the same publication
II-1 to II-102. Compounds represented by general formula (H) and general formula (Ha) described in JP-A-7-104429, specifically, compound H- described on pages 8 to 15 of the same publication.
1-H-44. A compound having an anionic group or a nonionic group forming an intramolecular hydrogen bond with a hydrogen atom of hydrazine in the vicinity of a hydrazine group described in Japanese Patent Application No. 7-191007, particularly a compound of the general formula (A) , General formula (B), general formula (C), general formula (D), general formula (E),
Compounds represented by the general formula (F), specifically, compounds N-1 to N-30 described in the publication. Japanese Patent Application No. 7-19100
A compound represented by the general formula (1) described in No. 7, specifically, compounds D-1 to D-55 described in the same gazette.

The hydrazine-based nucleating agent of the present invention can be used in a suitable water-miscible organic solvent, for example, alcohols (methanol, ethanol, propanol, fluorinated alcohol), ketones (acetone, methyl ethyl ketone), dimethylformamide, dimethyl sulfoxide, It can be used by dissolving it in methyl cellosolve or the like.

Further, by using a well-known emulsification dispersion method, an oil such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate, or an auxiliary solvent such as ethyl acetate or cyclohexanone is used to dissolve the compound. An emulsified dispersion can be prepared and used. Alternatively, a powder of a hydrazine derivative can be dispersed in water by a ball mill, a colloid mill, or an ultrasonic wave by a method known as a solid dispersion method and used.

The hydrazine nucleating agent of the present invention may be added to any silver halide emulsion layer or other hydrophilic colloid layer on the silver halide emulsion layer side with respect to the support.
It is preferably added to the silver halide emulsion layer or the hydrophilic colloid layer adjacent thereto.

The addition amount of the nucleating agent of the present invention is preferably 1 μmol to 10 mmol, more preferably 10 μmol to 5 mmol, most preferably 20 μmol to 5 mmol, per 1 mol of silver halide.

The light-sensitive material of the present invention may be provided with a surface protective layer for preventing the light-sensitive material from sticking and protecting the image.

As a binder for the surface protective layer, a known natural or synthetic polymer can be used. Examples of the binder include gelatin, polyvinyl alcohol, polyvinyl acetate, cellulose acetate, cellulose acetate butyrate, polyolefin, polystyrene, and various polymers described for the binder in the photosensitive layer.

The surface protective layer can be formed by applying a coating solution of a water-based or organic solvent-based solvent. However, considering the cost, it is more advantageous to use a coating solution of an aqueous solvent.

The preferred thickness of the surface protective layer is 0.2 to 10 μm, more preferably 1 to 5 μm per layer.

The light-sensitive material of the present invention may be provided with a back layer, an intermediate layer, an antihalation layer, a conductive layer, and the like, if necessary, in addition to the photosensitive layer and the surface protective layer. As the binder for these layers, the polymers described for the photosensitive layer, surface layer and surface protective layer may be used. Of course, the solvent of the coating solution for these layers may be an aqueous solvent or an organic solvent solvent.

The light-sensitive material of the present invention may contain, if necessary, a crosslinking agent such as an isocyanate type or an epoxy type, a surfactant such as an anionic type, a nonionic type or a cation type, a matting agent such as SiO ₂ and polymethyl methacrylate, Sliding agents such as silicone and paraffin, antihalation dyes and other dyes, and fillers such as colloidal silica may be added.

The method of applying each layer of the light-sensitive material of the present invention is not particularly limited, and a known method such as a bar coater method, a curtain coat method, an immersion method, an air knife method, and a hopper application method can be used.

The support used for the light-sensitive material of the present invention is not particularly limited. For example, paper, polyester, polystyrene, or the like can be used.

Among them, biaxially stretched polyethylene terephthalate having a thickness of about 50 to 300 μm has strength,
It is a preferred support from the viewpoint of chemical resistance and the like. The support may have been subjected to a surface treatment or an undercoat.

The method of exposing the light-sensitive material of the present invention is not particularly limited. For example, a tungsten lamp, a mercury lamp, a laser light source, a CRT light source, a xenon lamp, an iodine lamp, or the like can be used. Particularly preferred among these are laser light sources.

[0088]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should be understood that the present invention is by no means restricted thereto.

Example 1 (1) Preparation of Sample Nos. 102 to 120 <Preparation of Silver Halide Particles> 22 g of phthalated gelatin and 30 mg of potassium bromide were dissolved in 700 ml of water and the temperature was adjusted to 3
After adjusting the pH to 5.0 at 5 ° C., 159 ml of an aqueous solution containing 18.6 g of silver nitrate and 9 parts of potassium bromide and potassium iodide were added.
An aqueous solution containing a molar ratio of 2: 8 was added by a control double jet method over 10 minutes while maintaining the pAg at 7.7. Then, 476 ml of an aqueous solution containing 55.4 g of silver nitrate, 9 μmol / l of dipotassium hexachloroiridate and 1 mol / l of potassium bromide were added to pAg
Controlled by the control double jet method while keeping at 7.7
Added over 0 minutes. After that, the pH was lowered to perform coagulation sedimentation and desalting treatment, and 0.1 g of phenoxyethanol was added.
pH 5.9, pAg 8.2 and silver iodobromide grains (iodine content core 8 mol%, average 2 mol%, average size 0.05 μm
Cubic grains having a projection area variation coefficient of 8% and a (100) plane ratio of 79%).

The thus obtained halide grains were heated to 60 ° C., and 85 μmol of sodium thiosulfate and 11 μmol of 2,3,4,5,6-pentafluorophenyldiphenylphosphine selenide per 15 mol of silver were added. Mole of tellurium compound 1, 3.4 μmol of chloroauric acid, thiocyanic acid 2
After adding 60 μmol and ripening for 120 minutes, the mixture was rapidly cooled to 30 ° C. to obtain desired silver halide grains.

<Preparation of Organic Acid Silver Emulsion> Stearic acid
3 g, 0.5 g of arachidic acid, 8.5 g of behenic acid and 300 ml of distilled water were mixed at 90 ° C. for 15 minutes, 31.1 ml of a 1N aqueous solution of NaOH was added over 15 minutes with vigorous stirring, and the temperature was lowered to 30 ° C. did. Next, 7 ml of a 1N aqueous solution of phosphoric acid was added, and 0.02 g of N-bromosuccinimide was added while stirring more vigorously. Then, the silver halide grains prepared in advance were adjusted so that the silver halide amount was 2.5 mmol. Was added. Furthermore, 1N-silver nitrate aqueous solution 2
5 ml was added over 2 minutes and stirring was continued for 90 minutes. Thereafter, the solid content was separated by suction filtration, and the solid content was washed with water until the conductivity of the filtrate became 30 μS / cm.

Thereafter, the solid was dried under vacuum to obtain a silver halide / organic acid silver solid. To 10 g of this solid was added 40 g of a 10 wt% aqueous solution of hydroxypropylcellulose, and 0.1 mmol of pyridinium bromide perbromide and 0.15 mol of calcium bromide dihydrate were added. An aqueous dispersion (dispersion 1) of silver halide / silver organic acid having a particle size of about 1 μ was obtained.

<Preparation of Coating Solution for Photosensitive Layer> Separately, 10 mg of phenylthiosulfonic acid, 60 mg of Dye 1 and 30 mg of Dye 2 were prepared.
mg of 2-mercapto-5-methylbenzimidazole, 2 g of 4-chlorobenzophenone-2-carboxylic acid 2
1.5 g, 5-tribromomethylsulfonyl-2-methylthiadiazole 8 g, 2-tribromomethylsulfonylbenzothiazole 6 g, 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5 -150 g of trimethylhexane, 4,6-ditrichloromethyl-
5 g of 2-phenyltriazine, disulfide compound 1
2 g and 5 g of tetrachlorophthalic acid were mixed with 250 g of an aqueous solution of hydroxypropylcellulose (10 wt%) and dispersed with a homogenizer to obtain an aqueous dispersion of the above compound.

10.3 g of this dispersion was mixed with 150 g of dispersion 150.
Mixed with a binder (type is as shown in Table 1)
Was added, and 3 mg of sodium P-dodecylbenzenesulfonate was added. Distilled water was added thereto to prepare a 200 ml coating solution. PVA is polyvinyl alcohol.
The additive compounds used above are shown below.

[0095]

Embedded image

<Preparation of Coating Solution for Surface Protective Layer> Lime-treated gelatin 4 g Phthalazine (added with a 5 wt% water / methanol = 1/1 (weight ratio) solution) 480 mg 4-methylphthalic acid sodium salt (added with a 4% aqueous solution) 240 mg Polymethyl methacrylate fine particles (average particle size: 5 μm) 80 mg C ₇ F ₁₅ COONa 20 mg Sodium P-dodecylbenzenesulfonate 20 mg Distilled water was added to make 100 ml.

<Preparation of Sample> Biaxially stretched 175 μm thick
m on one side of a polyethylene terephthalate support
The binder was applied to a coating amount of 1.5 g / m ² and dried at 50 ° C. for 20 minutes. Thus 1.5 μm
A thick (dry film) back layer was formed.

Further, a photosensitive layer was coated on the opposite side so that the coated silver amount was 2.3 g / m ² and dried at 50 ° C. for 20 minutes. The thickness of the photosensitive layer was 20 μm in dry film thickness.

Subsequently, a surface protective layer was applied thereon so that the coating amount of the binder became 2 g / m ^2, and dried at 50 ° C. for 20 minutes to form a 1.6 μm thick layer. Thus, Sample Nos. 102 to 120 were obtained.

(2) Preparation of Sample No. 101 Sample No. 10 was prepared except that the photosensitive layer formulation was changed as follows.
Sample No. 101 in which the photosensitive layer was coated with an organic solvent was prepared in the same manner as in No. 2-120.

<Preparation of Organic Acid Silver Emulsion> Sample No. 102-
Silver halide / silver organic acid solid 1 described at 120
0 g of polyvinyl butyral (denka butyral # 30)
00k (manufactured by Denki Kagaku Kogyo KK) 4 g and 2-butanone 3
6 g were added.

Then, 0.1 mmol of pyridinium perbromide and 0.15 mmol of calcium bromide dihydrate were added and dispersed with a homogenizer, and a silver halide / organic acid silver dispersion having an average particle size of about 1 μm was obtained. (Dispersion 2) was obtained.

<Preparation of Coating Solution for Photosensitive Layer> 10 mg of sodium phenylthiosulfonate, 60 mg of Dye 1, 30 mg of Dye 2, 2 g of 2-mercapto-5-methylbenzimidazole, 4-chlorobenzophenone-2-carboxylic acid 21.5 g, 5-tribromomethylsulfonyl-2-methylthiadiazole 8 g, 2-tribromomethylsulfonylbenzothiazole 6 g, 4,6-ditrichloromethyl-2-phenyltriazine 5 g, disulfide compound 1 2 g, tetrachlorophthalate 5 g of acid is dissolved in 445 g of 2-butanone, and polyvinyl butyral (PV
B: A solution 1 was prepared by adding 5 g of denkabutyral # 3000k).

<Preparation of Coating Solution for Back Layer> Binder (type: Table 1) 15 g Distilled water 1000 g Sodium p-dodecylbenzenesulfonate 30 mg Dinacol EX313 (epoxy compound manufactured by Nagase Kasei Kogyo Co., Ltd.) 100 mg Dye a 50 mg Dye b 110 mg Dye c 40 mg Dye d 50 mg Polymethyl methacrylate fine particles (average particle size 5 μm) 20 mg The dyes used in the above are shown below.

[0105]

Embedded image

11.1 g of this solution and 250 g of Dispersion were mixed and further mixed with polyvinyl butyral (Butuar B-7).
6 (manufactured by Monsanto Co., Ltd.) 10 g, Megafac F17
3 mg of 6P (manufactured by Dainippon Ink and Chemicals, Inc.) was added, and 2-butanone was added thereto to prepare a 200 ml coating solution.

For the above sample Nos. 101 to 120,
The water content of the binder used in the photosensitive layer was determined as follows, and the photographic performance was evaluated as follows.

<Evaluation of moisture content of photosensitive layer binder> A solution (or dispersion) of the polymer used for the photosensitive layer was coated on a glass plate and dried at 50 ° C. for 1 hour to obtain a thickness of about 100 μm.
Was obtained. However, when a mixture of two or more polymers was used as a binder for the photosensitive layer, a model film was prepared by mixing the polymers at the same ratio. The polymer model film thus obtained was peeled off from the glass plate and humidified in an atmosphere at 25 ° C. and 60% RH for 3 days, and the weight (w ₁ ) was measured. Next, 25 polymer model membranes were added.
After placing in vacuum for 3 days, the mixture was quickly placed in a weighing bottle of known weight and its weight (w ₀ = w ₃ −w ₂ ) was measured (where w ₃ is the weight of the polymer model membrane and the weighing bottle, w
₂ is the weight of the weighing bin). Using w ₀ and w ₁ , the water content was determined by the following equation. Equilibrium water content at 25 ° C. and 60% RH = ｛(w ₁ −w ₀ )
/ W ₀ ｝ × 100 (%)

<Evaluation of Photographic Performance> The photosensitive material was exposed to light by a laser sensitometer equipped with an 810 nm diode in an atmosphere of 25 ° C. and 60% RH, and then heated (developed) at 120 ° C. for 25 seconds. The resulting images were evaluated (sensitivity, fog and maximum density ( _Dmax )) using a densitometer (normal temperature photographic properties). The sensitivity was evaluated by the reciprocal of the ratio of the exposure amount giving a density 0.3 higher than the fog (minimum) density ( _Dmin ). It was expressed by relative evaluation with reference to 101. The angle between the exposure surface of the photosensitive material and the exposure laser beam was 80 degrees.

In the above measurement, a light-sensitive material sample was treated at 25 ° C.
The test was performed after placing in an atmosphere of 0% RH.

Further, the same evaluation was performed under an atmosphere of 25 ° C. and 80% RH (high humidity photographic property). In this case, the measurement was performed after the photosensitive material sample was placed in an atmosphere of 25 ° C. and 80% RH for 24 hours.

Table 1 shows the evaluation results.

[0113]

[Table 1]

From the results shown in Table 1, it can be seen that when the polymer of the present invention is used as the main binder in the photosensitive layer binder, there is no fog increase in a high humidity atmosphere. Further, coating with a water solvent is possible, which is preferable in terms of environment and cost.
On the other hand, when the water content of the polymer exceeds 2 wt%, fog rises, and the water content of the coating solvent becomes 30 wt%.
If less than the stability of the coating solution is reduced, agglomeration occurs,
The surface condition becomes poor. When an organic solvent is used as a coating solvent, there is no particular problem in photographic properties, but it is extremely disadvantageous in terms of environment and cost.

[0115]

According to the present invention, it is possible to coat a photosensitive layer without using an organic solvent which is harmful to the environment and the human body and disadvantageous in cost. Also, fog is low even when stored in a high humidity atmosphere.

Claims (4)

[Claims] 1. A photothermographic material comprising a photosensitive layer containing a photosensitive silver halide on at least one surface of a support, and containing a non-photosensitive silver salt and a reducing agent for the non-photosensitive silver salt. The main binder of the photosensitive layer is a polymer having an equilibrium water content of 2% by weight or less at 25 ° C. and 60% RH, and the photosensitive layer is coated and dried using a coating solution in which 30% by weight or more of the solvent is water. A photothermographic material characterized by being formed by: 2. The photothermographic material according to claim 1, wherein the non-photosensitive silver salt is an organic silver salt. 3. The photothermographic material according to claim 1, wherein the main binder of the photosensitive layer is a polymer dispersed in an aqueous solvent. 4. The photothermographic material according to claim 1, wherein the photosensitive layer is formed by using a coating solution in which 70% by weight or more of a solvent is water.