JP2000292881A - Heat developable material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form an image forming layer even by coating with a coating fluid containing an aqueous solvent which is advantageous to environmental protection and cost and to obtain a heat developable material less liable to fog even when it is preserved at high humidity. SOLUTION: The heat developable material consists of a substrate and an image forming layer containing photosensitive silver halide grains and an organic silver salt. When 10,000 mm2 of the heat developable material is immersed in a liquid dispersion medium in which >=30 mass % of 100 ml is water at 40 deg.C for 60 min and then the heat developable material is removed, the silver potential of the liquid dispersion medium at 40 deg.C is <=200 mV.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-developable material for forming an image by heat development.
The present invention relates to a heat-developable material having an image-forming layer applied using an aqueous coating solution and having less fog even when stored under high humidity.

[0002]

2. Description of the Related Art In recent years, in the field of printing plate making and medical treatment, a waste liquid accompanying wet processing of an image forming material has become a problem in terms of workability. There is a strong demand for weight loss. Therefore, there is a need for a technique relating to a photothermographic material for photographic technology that can form a high-resolution and clear black image by thermal development. As this technique, for example, U.S. 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) are well known. These photosensitive materials are usually 80
Since development is performed at a temperature of not less than ° C., it is called a heat development material.

[0003] However, it is known that these heat-developable materials increase fog in long-term storage under high humidity and give unfavorable results.

Conventionally, most of this type of heat developing material forms an image forming layer by applying a coating solution using an organic solvent such as toluene, methyl ethyl ketone or methanol as a solvent. This is because polyvinyl acetal such as polyvinyl butyral used as a binder dissolves only in an organic solvent. However, the use of an organic solvent as a solvent is disadvantageous not only for the adverse effect on the human body in the production process but also for the cost due to the recovery of the solvent and the like.

Therefore, as a method of forming an image forming layer by using a coating solution of a water solvent which does not have such a concern, for example, JP-A-49-562626 and JP-A-50-151138.
No. 53-116144, No. 58-28737,
JP-A-60-61747 describes an example in which water-soluble gelatin, polyvinyl alcohol, and polyvinyl acetal are used as a binder.

Further, in recent years, Japanese Patent Laid-Open No.
Nos. 9 and 10-73901 describe examples of image forming layers using a water-dispersible acrylic polymer and a water-dispersible polyvinyl acetal as a binder.

Certainly, when such a binder is used,
The image forming layer can be formed by using a coating solution of a water solvent, so that there are great environmental and cost advantages.

However, when an image forming layer is formed using a coating solution of such a water solvent, the problem of fogging due to long-term storage under high humidity becomes particularly noticeable. It is also desired to reduce the thickness of the image forming layer of the heat developing material.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to form an image forming layer by applying a coating solution of a water solvent which is advantageous in terms of environmental protection and cost, and to prevent fog even under high humidity storage. Is to provide a low heat developing material. Also,
Another object of the present invention is to obtain a heat developing material which can provide good performance even when the image forming layer is made thin.

[0010]

The above object is achieved by the following.

1) In a heat developing material comprising a support and an image forming layer containing photosensitive silver halide grains and an organic silver salt, 10,000 mm ² of the heat developing material is converted to 100 m
In a liquid dispersion medium in which 30% by mass or more of
After the immersion for 60 minutes, the silver potential at 40 ° C. of the liquid dispersion medium was 200 mV when the thermal developing material was removed.
A heat developing material characterized by the following.

2) The heat-developable material as described in 1) above, wherein either the image forming layer or the constituent layer contains a reducing agent or a reducing agent precursor.

3) The image forming layer is 30% by mass of the liquid dispersion medium.
The heat developing material according to the above 1), wherein the heat developing material is formed by coating and drying using a coating liquid having a silver potential of 200 mV or less.

4) The image forming layer is 30% by mass of the liquid dispersion medium.
The heat-developable material as described in 1) above, wherein the heat-developable material is formed by coating and drying using a coating solution that is an organic solvent.

(5) The heat-developable material as described in (1) above, wherein the organic silver salt is a silver salt with the polymer represented by the general formula (1).

6) The heat-developable material as described in 5) above, wherein 95% or more of the acid groups of the polymer form an organic silver salt.

(7) The heat-developable material as described in (5) above, wherein the acid group is a carboxyl group.

8) The heat-developable material as described in 1) above, wherein the organic silver salt is a silver salt of a polymer formed by polyaddition of a mixture containing at least a carboxyl group-containing dihydroxy compound and a diisocyanate compound.

9) The heat-developable material as described in 5) or 8) above, wherein the organic silver salt is contained in 50% by mass or more of the image forming layer, and the binder is contained in 50% by mass or less of the image forming layer. .

(10) The heat-developable material as described in (9) above, wherein the thickness of the image forming layer is 1 to 10 μm.

(11) The image forming layer as described in (1) above, wherein the image forming layer is formed by applying a coating solution comprising an organic silver salt and a liquid dispersion medium containing 30% by mass or more of water as a coating solution. A method for producing a heat developing material.

Hereinafter, the present invention will be described in detail. The heat development material of the present invention has a support, an image forming layer containing an organic silver salt, and a constituent layer provided on the same side of the support as the image forming layer. Further, the image forming layer or the constituent layer contains photosensitive silver halide grains. Further, the heat developing material 10000 mm ^2, 40 ° C., 10
After being immersed in 0 ml of a liquid dispersion medium containing 30% by mass or more of water for 60 minutes, the heat development material is removed from the liquid dispersion medium, and 40 ° C. in the liquid dispersion medium after the heat development material is removed. Has a silver potential of 200 mV or less. The method for measuring the silver potential is the same as the method for measuring the silver potential of the coating solution for the image forming layer described below.

The constituent layer refers to a layer other than the image forming layer, for example, a protective layer for protecting other constituent layers or the image forming layer, an undercoat layer, an antistatic layer, and the like. further,
The heat developing material may be provided with a backing layer or the like on the side of the support opposite to the image forming layer.

The photosensitive silver halide grains may be contained in the image forming layer together with the organic silver salt, or may be contained in a constituent layer adjacent to the image forming layer. More preferably, it is contained in the image forming layer.

It is preferable that the image forming layer or the constituent layer contains a reducing agent or a precursor of the reducing agent. In particular, the image forming layer or the layer adjacent to the image forming layer,
It is preferable to include a reducing agent or a precursor of the reducing agent.

One of the preferable constitutions for achieving a heat-developable material satisfying the above conditions is a constitution containing a silver salt with a polymer represented by the following general formula (1) as an organic silver salt.

Formula (1)-(A) _a- (B) _b -A represents a repeating unit derived from a monomer having an acid group, and B represents a repeating unit derived from a monomer other than A. a and b represent a copolymerization ratio, a is 5 to 95% by mass, b is 5 to 95% by mass, and a + b = 100% by mass.

A may be a repeating unit derived from a monomer containing an acid group, and may be a total of a plurality of repeating units derived from a plurality of monomers. Similarly, B may be a repeating unit derived from a monomer other than A (that is, a monomer containing no acid group), and may be a total of a plurality of types of repeating units derived from a plurality of types of monomers. A is 10 to 90
%, More preferably 20 to 80% by mass.

Further, 50 to 100% by mass, preferably 70 to 100% by mass of the organic silver salt contained in the image forming layer,
More preferably, 90 to 100% by mass is an organic silver salt with the above polymer. An organic silver salt with a polymer and an organic silver salt such as silver behenate may be used in combination, or only an organic silver salt with a polymer may be contained in the heat developing material as an organic silver salt.

Further, in the organic silver salt which is a silver salt with the polymer of the general formula (1), it is preferable that 95% or more of all the acid groups of the polymer form a silver salt. It is more preferably at least 99%.

In the general formula (1), the acid group A is preferably a monomer containing a carboxyl group. In this case, A may be a repeating unit derived from a monomer having a carboxyl group, and may be a total of a plurality of types of repeating units derived from a plurality of types of monomers. Similarly, B may be a repeating unit derived from a monomer other than A (a monomer containing no carboxyl group), and may be a total of a plurality of repeating units derived from a plurality of monomers.

When an organic silver salt which is a silver salt with the polymer of the general formula (1) is used, it is preferable that the silver salt with the polymer of the general formula (1) also functions as a binder for the image forming layer. That is, the image forming layer contains 50% by mass or more of the organic silver salt which is a silver salt with the polymer of the general formula (1) in the image forming layer. It is preferable that the content of the binder which is not a silver salt is 50% by mass or less of the image forming layer. More preferably, the organic silver salt which is a silver salt with the polymer of the general formula (1) is contained in an amount of 70 to 100% by mass of the image forming layer, and more preferably 90 to 100% by mass.

In the image forming layer, the general formula (1)
More preferably, the content of the binder which is not a silver salt with the polymer of the image forming layer is 30% by mass or less of the image forming layer.
More preferably, the content is 10% by mass or less. This configuration is preferable because the thickness of the image forming layer can be reduced.
The preferred thickness of the image forming layer is 1 to 10 μm. More preferably, it is 2 to 8 μm.

The heat-developable material of the present invention is preferably produced as follows. After applying the coating solution for image forming layer on the support, the support coated with the coating solution for image forming layer is dried. Of course, after providing the various constituent layers between the support and the image forming layer, the coating solution for the image forming layer may be applied, or after the image forming layer is provided, the various constituent layers may be provided thereon. Good.

According to the present invention, 30% by mass or more of the liquid dispersion medium of the coating solution for the image forming layer is water (preferably 60%).
Mass%) or 30% by mass or more (preferably 60% by mass or more) of the liquid dispersion medium of the coating solution for the image forming layer is an organic solvent. Good long-term storage stability. In particular, when 30% by mass or more of the liquid dispersion medium of the coating liquid for the image forming layer is water, the effect is remarkable. Note that as the organic solvent, toluene, methyl ethyl ketone, methanol, and the like can be preferably used.

When 30% by mass or more of the liquid dispersion medium of the coating solution for the image forming layer is water, the silver potential of the coating solution is 2%.
It is preferably at most 00 mV. In addition, it is more preferable that 50% by mass or more of the liquid dispersion medium of the coating liquid for the image forming layer is water, and it is further preferable that 70% by mass or more is water. Further, the silver potential of the coating solution is preferably from 0 to 200 mV, more preferably from 20 to 150 mV.
mV. According to this configuration, even when an aqueous coating solution that has a greater problem in long-term storage properties is used, the long-term storage properties can be improved.

Of course, the organic silver salt which is a silver salt with the polymer of the formula (1) is used regardless of whether the liquid dispersion medium of the coating solution is an aqueous solvent or an organic solvent. be able to.

The solvent of the coating solution for forming the image forming layer of the heat-developable material of the present invention comprises water or a mixture of water and a water-miscible organic solvent with an upper limit of 70% by mass. Preferably, the content of the water-miscible organic solvent is less than 5% by weight. Examples of the water-miscible organic solvent include alcohols such as methanol, ethanol and propanol, cellosolves such as methyl cellosolve, ethyl cellosolve and butyl cellosolve, acetates such as methyl acetate and ethyl acetate, dimethylformamide and dimethylacetamide. Examples thereof include ketoamides, carbonates such as dimethyl carbonate and diethyl carbonate, and ketones such as acetone and methyl ethyl ketone.

The silver potential of the coating solution for the image forming layer of the present invention is as follows:
200 mV or less. Here, the silver potential is defined as Ag / AgCl in a 3 mol / L solution through a salt bridge composed of a silver electrode (purity of 99.99% or more) and a 10% KNO ₃ salt solution.
It is defined as a potential difference generated between the two electrodes when the electrode and the reference electrode are brought into contact with the coating solution kept at 40 ° C. The silver potential is 0 to 200 mV, more preferably 2 to 200 mV.
0 to 150 mV. If it exceeds 200 mV, fog increases, and if it is less than 0 mV, sensitivity lowers.

The adjustment of the silver potential was performed using KCl, KBr, NaC
1, halogen compounds such as NaBr, nitrogen-containing organic compounds such as 5-methylbenzotriazole and 5-nitroindazole, and mercapto compounds such as 1-phenyl-5-mercaptotriazole and sodium 1-mercaptobenzthiazole-5-sulfonate Etc. can be used.

In the present invention, the organic silver salt is a reducible silver source, and an organic acid containing a reducible silver ion source, a heteroorganic acid, a silver salt of an acid polymer, and the like are used. Also useful are organic or inorganic silver salt complexes in which the ligand has a total stability constant for silver ions of 4.0 to 10.0. Examples of silver salts include Research Disclosure
Nos. 17029 and 29996, and include the following: salts of organic acids (eg, salts of gallic acid, oxalic acid, behenic acid, stearic acid, palmitic acid, lauric acid, etc.); silver carboxyalkylthio Urea salts (eg, 1- (3-carboxypropyl) thiourea, 1-
(3-carboxypropyl) -3,3-dimethylthiourea and the like); silver complexes of polymer reaction products of aldehydes and hydroxy-substituted aromatic carboxylic acids (for example, aldehydes such as formaldehyde, acetaldehyde, butyraldehyde and salicylic acid, Hydroxy-substituted acids such as benzylic acid 3,5-dihydroxybenzoic acid, 5,5-thiodisalicylic acid); silver salts or complexes of thioenes (for example, 3- (2-carboxyethyl) -4-hydroxymethyl-4) -Thiazoline-2-thioene and 3-carboxymethyl-4-methyl-4-thiazoline-2-thioene); imidazole, pyrazole, urazole, 1,
Complexes or salts of nitrogen acids with silver selected from 2,4-thiazole and 1H-tetrazole, 3-amino-5-benzylthio-1,2,4-triazole and benzotriazole; saccharin, 5-chlorosalicylaldoxime And silver salts of mercaptides.

Preferably, a polymer silver salt containing an acid group in the range of 5 to 95% by mass is used as the organic silver salt. The polymer containing the acid group of the present invention in the range of 5 to 95% by mass refers to a polymer having a side chain structure of a polymer chain having a repeating unit of an acid moiety such as carboxylic acid, sulfonic acid, or phosphoric acid of 5 to 9%.
It is most preferable to use an organic silver salt which is a polymer containing 5% by mass and forms a silver salt with the acid group.

The polymer has a polyethylene structure,
Polyamide, polyester, polyurethane and the like can be mentioned.

In the above general formula (1), examples of the monomer which gives a repeating unit in which A is a carboxyl group include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, styrene carboxylic acid, 2
-Carboxyethyl acrylate, 2-carboxyethyl methacrylate and the like, but the present invention is not limited to these. These monomers may be used alone or in combination of two or more. Of these, acrylic acid and methacrylic acid are particularly preferred.

Next, in the above general formula (1), the monomers giving the repeating unit represented by B are preferably the following acrylate monomers, methacrylate monomers, styrenes and vinyl halides. .

Examples of the acrylates include methyl acrylate, ethyl acrylate, n-butyl acrylate, t-butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, benzyl acrylate, acryl Phenyl acid and the like.

Examples of the methacrylates include methyl methacrylate, ethyl methacrylate, and n-methacrylate.
Butyl, t-butyl methacrylate, cyclohexyl methacrylate, isononyl methacrylate, benzyl methacrylate, phenyl methacrylate and the like.

Examples of the styrenes include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-tert-butylmethylstyrene, p-chlorostyrene and the like.

Examples of the vinyl halides include vinyl chloride and vinylidene chloride, but the present invention is not limited to these. These monomers may be used alone or in combination of two or more. Of these, methyl methacrylate is preferred,
T-butyl methacrylate and styrene are preferred, and methyl methacrylate is particularly preferred.

Further, when a crosslinkable monomer having two or more ethylenically unsaturated groups is contained as a component C as a part of the component B, more preferable results can be obtained. Examples of the crosslinkable monomer having two or more ethylenically unsaturated groups include divinylbenzene, 4,4′-isopropylidene diphenylene acrylate, 1,3-butylene acrylate, 1,3-butylene methacrylate,
1,4-cyclohexylene dimethylene dimethacrylate, diethylene glycol dimethacrylate, diisopropylidene glycol dimethacrylate, divinyloxymethane, ethylene glycol diacrylate, ethylene glycol dimethacrylate, ethylidene diacrylate, ethylidene dimethacrylate, 1,6-diacrylamide hexane N, N'-methylenebisacrylamide, N, N '-(1,2-dihydroxy) methylenebisacrylamide, 2,2'-dimethyl-1,3-trimethylene dimethacrylate, phenylethylene dimethacrylate, tetraethylene glycol Dimethacrylate, tetramethylene diacrylate, tetramethylene dimethacrylate, 2,2,2-trichloroethylidene dimethacrylate, trimethacrylate Chi glycol diacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, triethylene glycol dimethacrylate, 1,3,5-acryloyl-hexane -
s-triazine, bisacrylamidoacetic acid, ethylidene trimethacrylate, propylidine triacrylate,
Vinyl allyloxy acetate, and the like,
The present invention is not limited to these.

These monomers may be used alone or in combination of two or more. Of these, ethylene glycol dimethacrylate is preferred,
Divinylbenzene and N, N'-methylenebisacrylamide, particularly preferably ethylene glycol dimethacrylate.

In the general formula (1), a is 10 to 8
It is preferably 0% by mass, particularly preferably 15 to 60% by mass. b is preferably from 20 to 90% by mass, particularly preferably from 40 to 85% by mass. The content of the component C as a part of the component B is preferably 1 to 20% by mass, particularly preferably 3 to 15% by mass.

Further, a polymer formed by polyaddition of a mixture containing at least a carboxyl group-containing dihydroxy compound and a diisocyanate compound is also preferably used. This polymer is a kind of polyurethane polymer and is characterized by containing a carboxyl group in its structure. Specific examples of the carboxyl group-containing dihydroxy compound include 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (hydroxymethyl) butanoic acid,
2,2-bis (hydroxyethyl) propionic acid, 2,
Examples thereof include 2-bis (hydroxyethyl) butanoic acid, 2,2-bis (hydroxypropyl) propionic acid, and 2,2-bis (hydroxypropyl) butanoic acid. Specific examples of the diisocyanate compound include 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate. The content of the carboxyl group-containing dihydroxy compound is preferably from 10 to 60% by mass, and more preferably from 20 to 50% by mass. In addition to the above components, in order to adjust the physical properties of the polyurethane or to make the structure three-dimensional, a polyhydroxy compound such as ethylene glycol, triethylene glycol, diethylene glycol, glycerin, pentaerythritol, or sorbitol may be added as a component. good. In that case,
The addition amount of the polyvalent hydroxy compound is preferably from 1 to 30% by mass, and more preferably from 5 to 20% by mass.

Specific examples of the polymer preferably used in the present invention are shown below, but the present invention is not limited to these. (Numbers represent mass%) P-1 methacrylic acid / styrene copolymer (30/70) P-2 methacrylic acid / t-butyl acrylate copolymer (60/40) P-3 methacrylic acid / hexyl acrylate copolymer Polymer (50/50) P-4 Methacrylic acid / 2-ethylhexyl acrylate copolymer (40/60) P-5 Methacrylic acid / phenyl acrylate copolymer (40/60) P-6 Methacrylic acid / cyclohexyl acrylate Polymer (40/60) P-7 Methacrylic acid / methyl methacrylate copolymer (20/80) P-8 Methacrylic acid / ethyl methacrylate copolymer (30/70) P-9 Methacrylic acid / n-butyl methacrylate / Cyclohexyl acrylate copolymer (40/20/40) P-10 methacrylic acid / 2 Ethylhexyl methacrylate copolymer (40/60) P-11 Acrylic acid / styrene copolymer (20/80) P-12 Acrylic acid / hexyl acrylate copolymer (40/60) P-13 Acrylic acid / isononyl acrylate Copolymer (60/40) P-14 Acrylic acid / 2-ethylhexyl acrylate copolymer (60/40) P-15 Acrylic acid / phenyl acrylate copolymer (50/50) P-16 Itaconic acid / styrene Copolymer (40/60) P-17 Itaconic acid / 2-ethylhexyl acrylate copolymer (40/60) P-18 Itaconic acid / benzyl acrylate copolymer (40/60) P-19 Maleic acid / styrene Copolymer (40/60) P-20 Maleic acid / hexyl acrylate copolymer (20 / 0) P-21 maleic acid / phenyl acrylate copolymer (40/60) P-22 methacrylic acid / methyl methacrylate / ethylene glycol dimethacrylate (40/50/10) P-23 methacrylic acid / n-butyl acrylate / Ethylene glycol dimethacrylate (30/60/10) P-24 acrylic acid / methyl methacrylate / ethylene glycol dimethacrylate (30/60/10) P-25 acrylic acid / methyl methacrylate / n-butyl acrylate / divinylbenzene ( 40/20/35/5) P-26 acrylic acid / ethyl acrylate / methylene bisacrylamide (40/55/5) P-27 2,2-bis (hydroxymethyl) propionic acid / 4,4'-diphenylmethane Diisocyanate polyaddition Form (50/50) P-28 2,2-bis (hydroxymethyl) butanoic acid / tolylene diisocyanate polyadduct (50/50) P-29 2,2-bis (hydroxymethyl) propionic acid / 4 4'-Diphenylmethane diisocyanate / hexamethylene diisocyanate / triethylene glycol polyadduct (40/35/10/15) Among the above polymers, polyethylene-based polymers can be obtained by a general emulsion polymerization method. The emulsion polymerization method is described in detail in Soichi Muroi, “Chemistry of Polymer Latex” (Polymer Publishing Association, 1970).
For the polyurethane type, see "Polyurethane Handbook" by Gunter Otel (Gunter Oerte
l: Polyurethane Handbook, 2
1, 1985), edited by Shunsuke Murahashi et al., “Synthetic Polymers” V p.
309-359 and the like.

The weight average molecular weight Mw of the polymer silver salt of the present invention is preferably from 1,000 to 1,000,000, more preferably from 3,000 to 500,000.

The silver salt of the polymer of the present invention can be obtained by mixing an aqueous solution or dispersion of the above-mentioned polymer with an aqueous solution of silver nitrate, and is described in a forward mixing method, a reverse mixing method, a simultaneous mixing method, and JP-A No. 9-127643. A controlled double jet method or the like as described above is preferably used. Further, it is preferable to add silver halide grains to an aqueous solution or dispersion of a polymer before mixing.

The silver salt of the polymer of the present invention is preferably contained at a silver amount of 0.5 to 3 g / m ² or less. More preferably, it is 0.8 to ² g / m ² or less.

The silver halide grains in the present invention function as an optical sensor. In order to suppress white turbidity after image formation and to obtain good image quality, it is preferable that the average particle size is small.
0 μm or less, more preferably 0.03 to 0.15 μm,
In particular, 0.03 to 0.11 μm is preferable. 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, it refers to the diameter of a sphere equivalent to the volume of silver halide grains.

The shape of the silver halide grains is not particularly limited, but the ratio occupied by the Miller index [100] plane is preferably high, and this ratio is 50% or more, and more preferably 7% or more.
It is preferably at least 0%, particularly preferably at least 80%. The ratio of the Miller index [100] plane is determined by T.M. using the dependence of the adsorption of the sensitizing dye on the [111] plane and the [100] plane. Tani, J .; Imaging Sci. , 29,
165 (1985).

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. The photographic emulsion used in the present invention is P.I. Chimie et by Glafkids
Physique Photographique (P
aul Montel, 1967); F. D
Photographic Emuls by uffin
ion Chemistry (The Focal P
Res., 1966); L. Zelikman
Making and Coating by et al
Photographic Emulsion (Th
e Focal Press, 1964) and the like. That is, any of an acidic method, a neutral method, an ammonia method, etc. may be used.
Any of a one-side mixing method, a simultaneous mixing method, a combination thereof and the like may be used. The silver halide may be added to the image-forming layer by any method, wherein the silver halide is arranged close to a reducible silver source. The silver halide may be prepared by converting part or all of the silver in the organic acid silver by the reaction between the organic acid silver and the halogen ion into silver halide, or preparing the silver halide in advance. In advance, this may be added to a solution for preparing an organic silver salt, or a combination of these methods is possible, but the latter is preferred. Generally, the silver halide is preferably contained in an amount of 0.75 to 30% by mass 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 preferable, and among them, when used for a photosensitive material for printing plate making, Rh, Re, Ru,
It is preferable to be selected from Ir and Os.

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

In the formula [ML ₆ ] ^m , M is a transition metal selected from the elements of Groups 6 to 11 of the periodic table, L is a ligand, and m is 0,-, 2-, 3- or 4-
Represents Specific examples of the ligand represented by L include halides (fluoride, chloride, bromide and iodide), cyanide, cyanate, thiocyanate, selenocyanate, tellurocyanate, azide and aquo. Ligand, nitrosyl, thionitrosyl and the like, preferably aquo, 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.

[0066] 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) Cl (CN) 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- These metal ions, metal complexes or metal complex ions may be used alone or in combination of two or more of the same and different metals. Good. The content of these metal ions, metal complexes or metal complex ions, generally is suitably 1 × 10 ^-9 ~1 × 10 ^-2 mol per mol of silver halide, preferably 1 × 10 ^{- It is 8} to 1 × 10 ^-4 mol.

The compounds providing these metals are preferably added during silver halide grain formation and incorporated into silver halide grains. Preparation of silver halide grains, that is, nucleation, growth, physical ripening, and chemical ripening are carried out. Although it may be added at any stage before and after sensitization, it is particularly preferable to add at the stage of nucleation, growth and physical ripening, more preferably at the stage of nucleation and growth, and most preferably. It is added 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 to the silver halide grains.
-306236, 3-167545, 4-76
No. 534, No. 6-110146, No. 5-273683
As described in the above publication, the particles can be contained with a distribution inside the particles. Preferably, they are contained with a distribution 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 charged into the reaction vessel immediately after the formation of the particles, during or during physical ripening, or at the time of chemical ripening.

The heat-developable 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 the following.

Aminohydroxycycloalkenone compounds (eg, 2-hydroxy-3-piperidino-2-cyclohexenone); aminoreductones esters (eg, piperidinohexose reductone monoacetate) as precursors of reducing agents N-hydroxyurea derivatives (e.g., Np-methylphenyl-N-hydroxyurea); hydrazones of aldehydes or ketones (e.g., anthracenaldehyde phenylhydrazone); phosphoramidophenols; phosphoramidoanilines; Hydroxybenzenes (e.g., hydroquinone, t-butyl-hydroquinone, isopropylhydroquinone and (2,5-dihydroxy-phenyl) methylsulfone); sulfhydroxamic acids (e.g., benzenes Sulfonamidoanilines (eg, 4- (N-methanesulfonamido) aniline); 2-tetrazolylthiohydroquinones (eg, 2-methyl-5- (1-phenyl-5-tetrazolylthio) hydroquinone Tetrahydroquinoxalines (eg, 1,2,3,4-tetrahydroquinoxaline); amide oximes; azines; combinations of aliphatic carboxylic acid arylhydrazides and ascorbic acid; combinations of polyhydroxybenzene and hydroxylamine; Reductone and / or hydrazine; Hydroxanoic acids; Combinations of azines and sulfonamidophenols; α-cyanophenylacetic acid derivatives;
A combination of -naphthol and a 1,3-dihydroxybenzene derivative; 5-pyrazolone; a sulfonamide phenol reducing agent; 2-phenylindane-1,3-dione and the like; chroman; 1,4-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, 2,2-bis (4-hydroxy-3-methylphenyl) propane , 4,4-ethylidene-bis (2-t-butyl-6-methylphenol), ultraviolet-sensitive ascorbic acid derivative); hindered phenols; 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).

[0073]

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In the formula, R is a hydrogen atom or a group having 1 to 1 carbon atoms.
10 alkyl group (e.g., -C ₄ H _9, 2,4,4-trimethyl pentyl) represents, R 'and R "is an alkyl group having 1 to 5 carbon atoms (e.g., methyl, ethyl, t- butyl ).

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

[0076]

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[0077]

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

As the binder for the heat developing material of the present invention, it is most preferable that the polymer of the above-mentioned polymer silver plays its role, but the following ones may be further added. That is, it is transparent or translucent, generally colorless, and forms a natural polymer, a synthetic resin, a polymer and a copolymer, and other film-forming media such as gelatin, gum arabic, poly (vinyl alcohol), hydroxyethyl cellulose, cellulose acetate, and cellulose. Poly (acrylates) such as acetate butyrate, poly (vinylpyrrolidone), casein, starch, poly (methyl methacrylic acid), poly (acrylic acid), poly (methacrylic acid), poly (vinyl chloride), copoly ( Styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-
Butadiene), poly (vinyl acetal) s (for example,
Poly (vinyl formal) and poly (vinyl butyral)), poly (ester) s, poly (urethane) s, phenoxy resins, poly (vinylidene chloride), poly (epoxides), poly (carbonates), poly (vinyl acetate) ), Cellulose esters and poly (amides). It may be hydrophilic or non-hydrophilic.

Particularly preferred are polyacrylates such as polymethylmethacrylic acid, copolystyrene-butadiene, polyvinyl acetal, cellulose esters and polyurethanes.

In the present invention, the binder amount of the photosensitive layer is preferably from 1.5 to 10 g / m ² . More preferably, it is 1.7 to 8 g / m ² . 1.5 g / m ²
If it is less than 1, the density of the unexposed portion is significantly increased, and may not be usable.

In the present invention, a matting agent is preferably contained on the photosensitive layer side. In order to improve the repeatability of the dimensions of the heat-developable material of the present invention, a polymer matting agent or an inorganic matting agent is added to the entire emulsion layer side. It is preferable that the content is 0.5 to 10% by mass relative to the binder.

The material of the matting agent preferably used in the present invention may be either an organic substance or an inorganic substance. For example, as inorganic substances, silica described in Swiss Patent No. 330,158, glass powder described in French Patent No. 1,296,995, etc., and alkali described in British Patent No. 1,173,181 etc. An earth metal or a carbonate such as cadmium or zinc can be used as a matting agent. Examples of organic substances include starch described in U.S. Pat. No. 2,322,037, Belgian patent 625,451 and British patent 98.
No. 1,198, etc .;
No. 3643, polystyrene or polymethacrylate described in Swiss Patent No. 330,158, polyacrylonitrile described in U.S. Pat. No. 3,079,257, U.S. Pat.
An organic matting agent such as polycarbonate described in JP-A-2,169 or the like 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 spherical shape. In the present invention, the particle diameter of the matting agent indicates the diameter converted into a sphere.

The matting agent preferably used in the present invention includes:
The average particle size is preferably from 0.5 to 10 μm, more preferably from 1.0 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 coefficient of variation of the particle size distribution is a value represented by the following equation. (Standard deviation of particle diameter) / (average value of particle diameter) × 100 The matting agent can be contained in any constituent layer. However, in order to achieve the object of the present invention, it is preferable that the matting agent is other than the photosensitive layer. And more preferably the outermost layer as viewed from the support.

The method of adding the matting agent may be a method of dispersing in a coating solution in advance and applying the same, or a method of applying the coating solution and spraying the matting agent before the drying is completed. Is also good. When a plurality of types of matting agents are added, both methods may be used in combination.

The heat-developable material of the present invention forms a photographic image by heat-development processing, and includes a reducible silver source (organic silver salt), a catalytically active amount of silver halide, a hydrazine derivative,
It is preferable that the heat developing material contains a reducing agent and, if necessary, a color tone agent for suppressing the color tone of silver in a state of being usually dispersed in an (organic) binder matrix.

The heat-developable material of the present invention is stable at room temperature, but is developed by heating to a high temperature (for example, 80 to 140 ° C.) after exposure. By heating, silver is generated 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, where the image is formed. This reaction process proceeds without supplying a processing liquid such as water from the outside.

The heat development 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. In order to control the amount of light passing through the photosensitive layer, or the wavelength distribution, a filter layer may be formed on the same side as the photosensitive layer or on the opposite side, or a dye or pigment may be included in the photosensitive layer. Is also good. As the dye, a compound disclosed in Japanese Patent Application No. 7-11184 is preferred. The photosensitive layer may be composed of a plurality of layers, and the sensitivity may be changed to a high-sensitive layer / low-sensitive layer or a low-sensitive layer / high-sensitive layer for adjusting the gradation. Various additives may be added to any of the photosensitive layer, the non-photosensitive layer, and other forming layers. The photothermographic material of the invention may contain, for example, a surfactant, an antioxidant, a stabilizer, a plasticizer, an ultraviolet absorber, a coating aid, and the like.

It is preferable to add a toning agent to the heat-developable material of the present invention. Examples of suitable toning agents are Research.
h Disclosure No. 17029, which includes:

Imides (for example, phthalimide), cyclic imides, pyrazolin-5-ones and quinazolinones (for example, succinimide, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and 2 , 4-thiazolidinedione), naphthalimides (eg, N-hydroxy-1,8-naphthalimide), cobalt complexes (eg, hexaamminetrifluoroacetate of cobalt), mercaptans (eg, 3-mercapto-1, 2,4-triazole), N
-(Aminomethyl) aryldicarboximides (eg, N- (dimethylaminomethyl) phthalimide),
The blocked pyrazoles, isothiuronium (is
othiuronium) derivatives and certain photobleaches (eg, N, N'-hexamethylenebis (1-carbamoyl-3,5-dimethylpyrazole);
Combination of 1,8- (3,6-dioxaoctane) bis (isothiuronium trifluoroacetate) and 2- (tribromomethylsulfonyl) benzothiazole, merocyanine dye (for example, 3-ethyl-5-
[(3-ethyl-2-benzothiazolinylidene) -1-
Methylethylidene] -2-thio-2,4-oxazolidinedione), phthalazinone, phthalazinone derivatives or metal salts of these derivatives (eg, 4- (1-naphthyl)
Phthalazinone, 6-chlorophthalazinone, 5,7-dimethoxyphthalazinone and 2,3-dihydro-1,4-phthalazinedione), a combination of phthalazinone and a sulfinic acid derivative (for example, 6-chlorophthalazinone and benzenesulfin) Sodium or 8-methylphthalazinone and sodium p-tolylsulfinate), a combination of phthalazinone and phthalic acid, phthalazine (including adducts of phthalazine and maleic anhydride) and phthalic acid, 2,
A combination with at least one compound selected from 3-naphthalenedicarboxylic acid or an o-phenylene acid derivative and an anhydride thereof (for example, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride); Quinazolinedione, benzoxazine or naphthoxazine derivative, benzoxazine-2,4-dione (for example, 1,3-benzoxazine-2,4-
Dione), pyrimidines and asymmetric triazines (eg, 2,4-dihydroxypyrimidine), tetraazapentalene derivatives (eg, 3,6-dimercapto-1,
4-diphenyl-1H, 4H-2,3a, 5,6a-tetrazapentalene).

The heat-developable material of the present invention may contain an antifoggant. Known as the most effective antifoggants are mercury ions. Regarding the use of mercury compounds as antifoggants in thermal developing materials,
For example, it is disclosed in U.S. Pat. No. 3,589,903. However, mercury compounds are environmentally unfriendly. Non-mercury antifoggants include, for example, US Pat.
6,075 and 4,452,885 and JP-A-5
Antifoggants such as those disclosed in 9-57234 are preferred.

Particularly preferred non-mercury antifoggants are US
Patent Nos. 3,874,946 and 4,756,999
-C (X₁) (X_Two)
(X _Three) (Where X₁And X_TwoIs halogen, X_ThreeIs hydrogen or
Is a hetero group having one or more substituents represented by halogen)
It is a cyclic compound. Examples of suitable antifoggants include:
JP-A-9-90550, paragraph numbers [0062] to [00]
63] are preferably used.
You.

Further, more suitable antifoggants are disclosed in US Pat. No. 5,028,523 and EP 600,58.
Nos. 7, 631,176 and 605,981.

The heat-developable material of the present invention includes, for example,
No. 3-159841, No. 60-140335, No. 63
No.-231437, No.63-259651, No.63-
Nos. 304242, 63-15245, U.S. Pat. Nos. 4,639,414, 4,740,455, 4,741,966, 4,751,175, and 4,835,096 The sensitizing dyes described in (1) can be used.

Useful sensitizing dyes for use in the present invention include, for example, Research Disclosure Item
m17643 IV-A (p.23, December 1978),
Item 1831X (August 1978, p. 437)
Or cited in the literature cited. In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of various scanner light sources can be advantageously selected. For example, JP-A-9-34078, JP-A-9-54409, and JP-A-9-80
No. 679 is preferably used.

[0098]

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

Example 1 [Production of Subbed Photographic Support] 8 W / m ² ··· on both sides of a polyethylene terephthalate support having a thickness of 130 μm.
The undercoating liquid a-1 shown below is applied to one side so as to have a dry film thickness of 0.8 μm, and dried to form an undercoating layer A-1. Was coated with the following undercoat coating solution b-1 so as to have a dry film thickness of 0.8 μm, and dried to form an undercoat layer B-1.

<< Undercoating Coating Solution a-1 >> Butyl Acrylate (30% by Mass) t-Butyl Acrylate (20% by Mass) Styrene (25% by Mass) 2-Hydroxyethyl Acrylate (25% by Mass) Copolymer Latex Liquid (Solid content 30%) 270 g (C-1) 0.6 g hexamethylene-1,6-bis (ethylene urea) 0.8 g Finish to 1 L with water << Undercoating solution b-1 >> Butyl acrylate (40% by mass) ) Styrene (20% by mass) Copolymer latex liquid of glycidyl acrylate (40% by mass) (solid content 30%) 270 g (C-1) 0.6 g Hexamethylene-1,6-bis (ethylene urea) 0.8 g Finish to 1L with water Then, on the upper surface of the undercoat layer A-1 and the undercoat layer B-1,
A corona discharge of 8 W / m ² · min. Was performed, and the following lower coating liquid a-2 was coated on the lower coating layer A-1 with a dry film thickness of 0.1 μm.
As the undercoat layer A-2, the undercoat layer B-1 is coated with the following undercoat upper layer coating solution b-2 so as to have a dry film thickness of 0.8 μm. Coating was performed as upper layer B-2.

<< Coating Solution a-2 for Subbing Upper Layer >> Gelatin 0.4 g / m ² Mass (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 Finished to 1 L with water << Lower upper coating liquid b-2 >> (C-4) 60 g Latex liquid containing (C-5) as a component (solid content: 20%) 80 g Ammonium sulfate 5g (C-6) 12g Polyethylene glycol (weight average molecular weight 600) 6g Finish to 1L with water

[0102]

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[0103]

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<Preparation of Silver Halide Grain Emulsion A> Water 90
After dissolving 7.5 g of inert gelatin and 10 mg of potassium bromide in 0 ml, adjusting the temperature to 35 ° C. and the pH to 3.0, 370 ml of an aqueous solution containing 74 g of silver nitrate and (9)
An aqueous solution containing potassium bromide and potassium iodide in a molar ratio of 8/2) and rhodium chloride in a controlled double jet method over a period of 10 minutes while maintaining 1 × 10 ⁻⁴ mol per mol of silver at a pAg of 7.7. Was added.

Thereafter, 4-hydroxy-6-methyl-
0.3 g of 1,3,3a, 7-tetrazaindene was added, the pH was adjusted to 5 with NaOH, the average particle size was 0.06 μm, the variation coefficient of the projected diameter area was 8%, and [10
0] Cubic silver iodobromide grains having an area ratio of 87% were obtained. This emulsion was subjected to coagulation sedimentation using a gelatin coagulant, desalted, and then phenoxyethanol (0.1 g) was added thereto.
g was adjusted to 7.5 to obtain silver halide grain emulsion A.

<Preparation of Polymer Silver Salt> Each of the polymers shown in Table 1 was weighed so as to have a solid content corresponding to 25 mmol of acid groups, and distilled water was added to make 300 ml. To this, a 1N aqueous sodium hydroxide solution was added over 15 minutes until the pH reached 8.7. Next, while maintaining at 30 ° C., 7 ml of a 1 mol / L phosphoric acid aqueous solution was added, and N-bromosuccinimide 0.02
g of silver halide grain emulsion A prepared above
Was added so that the amount of silver halide was 2.5 mmol. This solution was added with a solution prepared by dissolving 10 g of ossein gelatin and 1 g of polyoxyethylene dodecylphenyl ether (average number of ethylene units: 8) in 500 ml of distilled water, and dispersed with a homogenizer.
25 ml of a 1 / L silver nitrate aqueous solution at 30 ° C. for 30 minutes
Added over minutes. After the addition is completed, the mixture is further stirred for 30 minutes and subjected to ultrafiltration to remove water-soluble salts and the like until the conductivity of the filtrate reaches 30 μS / cm. An aqueous dispersion of silver halide / polymer silver having an average particle diameter of about 1 μm (PG-1 to PG-8)
Obtained.

<Preparation of Organic Acid Silver Salt> Stearic acid 1.3
g, arachidic acid 0.5 g, behenic acid 8.5 g, and distilled water 300 ml were mixed at 90 ° C. for 15 minutes, and a 1 mol / L sodium hydroxide aqueous solution was pH 8.7 with vigorous stirring.
Was added over 15 minutes until the temperature became 30 ° C. Next, 7 ml of a 1 mol / L phosphoric acid aqueous solution was added,
N-Bromosuccinimide 0.
After the addition of 02 g, the previously prepared silver halide grain emulsion A was added so that the silver halide amount was 2.5 mmol.

[0108] 10 g of this liquid was added to 500 ml of distilled water.
Of ossein gelatin, 1 g of polyoxyethylene dodecylphenyl ether (average number of ethylene units: 8) was added, and 25 ml of a 1 mol / L silver nitrate aqueous solution was added at a temperature of 30 ° C. for 30 minutes while dispersing with a homogenizer. And added. After the addition is completed, the mixture is further stirred for 30 minutes and subjected to ultrafiltration, so that the conductivity of the filtrate is 30 μS / cm.
Remove water-soluble salts until the average particle size is about 1 μm
Aqueous dispersion of silver halide / organic silver (organic silver salt B) was obtained.

<Preparation of Coating Solution for Image Forming Layer> The following layers were sequentially formed on the support provided with the undercoat layer as described above to prepare a sample. In addition, each drying was performed at 75 ° C. for 5 minutes.

Back side coating Back layer: A coating solution prepared by adding water to an aqueous solution or aqueous dispersion of the following composition was applied and dried so as to have the following coating amount.

Gelatin 7.0 g / m ² Dye-B 70 mg / m ² Dye-C 70 mg / m ²

[0112]

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Image forming layer surface side coating Image forming layer: Water was added to an aqueous dispersion of the following composition to prepare a coating solution. The coating solution was kept at 40 ° C., and Ag / AgCl in a 3 mol / L solution was passed through a salt bridge composed of a silver electrode (purity of 99.99% or more) and a 10% KNO ₃ salt solution.
The silver potential was measured using a silver electrometer formed from a reference electrode composed of an electrode, and then applied and dried so that the following amount was obtained.

Organic Silver Salt (See Table 2) Amount to be 2.0 g / m ² in terms of silver Binder (total amount of the polymer portion of the polymer silver salt of the present invention and polyvinyl butyral) 5.0 g / m ² silver sensitized according to the potential modifiers table 2 dye -1 2 mg / m ² antifoggant -1: pyridinium hydrobromide perbromide 0.3 mg / m ² antifoggant -2 1.2 mg / m ² antifoggant -3: 2-tribromomethylsulfonyl quinoline 120 mg / m ² phthalazone ^{360mg / m 2 A-4 1300mg} / m 2 high contrast agent H-1 100mg / m ² high contrast agent ^H-2 100mg / m 2

[0115]

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[0116]

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The thickness of the image forming layer was 8 μm when the polymer silver salt was used as the organic silver salt, and 17 μm when the silver behenate was used.

Surface protective layer: A coating solution prepared by adding water to an aqueous solution or aqueous dispersion of the following composition was applied and dried so as to have the following amount.

Gelatin 2.0 g / m ² Phthalazine 1.0 g / m ² 4-Methylphthalic acid 0.72 g / m ² Tetrachlorophthalic acid 0.22 g / m ² Tetrachlorophthalic anhydride 0.5 g / m ² Silica Matting agent (average particle size: 5 μm) 0.5 g / m ² << Evaluation of photographic performance >> The heat-developing material prepared above was split in half, and one was exposed with a laser sensitometer having a 780 nm semiconductor laser. Thereafter, heat development was performed at 130 ° C. for 25 seconds using a heat drum. At that time, exposure and development were performed in a room conditioned at 25 ° C. and 60% RH.
Evaluation of the obtained image (sensitivity, fog and maximum density (D
max)) was performed with a densitometer (room 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). 1
Was expressed as a relative evaluation on the basis of. The angle between the exposed surface of the heat developing material and the exposed laser beam was set to 80 degrees. The above measurement was carried out after placing the heat-developable material in an atmosphere of 25 ° C. and 60% RH for 24 hours. The rest is 25 ° C, 80% RH
After storing for 3 days in the atmosphere described above, the same evaluation as above was performed (high-humidity photographic property).

<< Evaluation of Silver Potential of Thermal Developing Material >> The thermal developing material 10000 mm ² prepared above was finely chopped to a size of 100 mm ² , and the whole amount was reduced to 40 ml in a 200 ml beaker.
Water / methanol (70/30) liquid 100 kept at 100 ° C
The sample was immersed in the solution for 60 minutes. After removing the heat-developable material, the silver potential was measured using the same silver electrometer as used for the measurement of the coating solution, while maintaining the solution temperature at 40 ° C. Table 2 shows the results of the evaluation.

[0121]

[Table 1]

[0122]

[Table 2]

From the results shown in Table 2, it can be seen that when the silver potential of the coating solution was adjusted within the range of the present invention, the fog increase under a high humidity atmosphere was small. Further, coating with a water solvent is possible, which is preferable in terms of environment and cost. Use of a polymer silver salt as the organic silver salt is preferable because the thickness of the image forming layer can be reduced while maintaining good storage stability.

Example 2 [Preparation of Subbed Photographic Support] 8 W / m ² ···
For one minute, the following undercoating coating liquid c is applied on one surface so as to have a dry film thickness of 0.8 μm, and dried to form an undercoating layer C. Undercoating liquid d
-1 was applied so as to have a dry film thickness of 0.8 μm, and dried to obtain an undercoat layer D-1.

<< Undercoat Coating Solution c >> Polyester Copolymer Dispersion Pesresin A-515GB (30%, manufactured by Takamatsu Oil & Fat Co., Ltd.) 200 ml Polystyrene fine particles (average particle size: 0.2 μm) 50 g Surfactant A (1 mass %) surfactant finish 1L in 20ml water _{a: C 9 H 19 -C 6} H 4 - (CH 2 CH 2) n H
n = 8.5 << Undercoat Coating Solution d-1 >> Styrene butadiene copolymer aqueous dispersion (styrene / butadiene / itaconic acid = 47/50/3 (mass ratio), concentration 30% by mass) 200 ml polystyrene fine particles ( (Average particle size: 2.5 μm) 0.1 g Finish to 1 L with water Subsequently, a corona discharge of 8 W / m ² · min is applied to the upper surface of the undercoat layer D-1 to apply the undercoat upper layer coating solution d-2 shown below. Coating was performed as a lower pulling upper layer D-2 having an antistatic function so as to have a dry film thickness of 0.8 μm.

<< Coating Solution d-2 for Lower Substrate >> Inert Gelatin 10 g Aqueous dispersion of tin oxide-antimony oxide composite fine particles (40% by mass) (described in JP-A-61-20033) 40 g Silica particles (average particle size) (Diameter: 3 μm) 0.1 g Finish to 1 L with water.

<Preparation of silver halide grain emulsion B>
After dissolving 7.5 g of inert gelatin and 10 mg of potassium bromide in 0 ml, adjusting the temperature to 35 ° C. and the pH to 3.0, 370 ml of an aqueous solution containing 74 g of silver nitrate and (9)
An aqueous solution containing potassium bromide and potassium iodide in a molar ratio of 8/2) and iridium chloride were added in an amount of 1 × 10 ^-4 per mole of silver.
Mole was added over 10 minutes by a controlled double jet method, keeping the pAg at 7.7.

Thereafter, 4-hydroxy-6-methyl-
0.3 g of 1,3,3a, 7-tetrazaindene was added, the pH was adjusted to 5 with NaOH, the average particle size was 0.06 μm, the variation coefficient of the projected diameter area was 8%, and [10
0] Cubic silver iodobromide grains having an area ratio of 87% were obtained. This emulsion was subjected to coagulation sedimentation using a gelatin coagulant, desalted, and then phenoxyethanol (0.1 g) was added thereto.
g was adjusted to 7.5 to obtain silver halide grain emulsion B.

<Preparation of silver salt of polymer> The average particle diameter was adjusted in the same manner as in Example 1 except that the silver halide grain emulsion A was changed to the silver halide grain emulsion B using the polymers shown in Table 1. An aqueous dispersion of silver halide / polymer silver of 1 μm was obtained.

<Preparation of Organic Acid Silver Salt> Except that silver halide grain emulsion A was changed to silver halide grain emulsion B, silver halide / organic silver having an average grain size of about 1 μm was used in exactly the same manner as in Example 1. An aqueous dispersion of silver (organic silver salt B-2) was obtained. First, a back layer was provided in exactly the same manner as in Example 1.

Coating on Image Forming Layer Surface The following layers were simultaneously coated and dried in this order on the support on which the undercoat layer C had been applied so that the respective materials had the following amounts, to prepare samples. . The drying was performed at 75 ° C. for 5 minutes.

Image forming layer: An aqueous dispersion of the following composition
Water was added to prepare a coating solution. Before coating, the coating solution was kept at 40 ° C., and 3 m was passed through a salt bridge composed of a silver electrode (purity of 99.99% or more) and a 10% KNO ₃ salt solution.
The silver potential was measured using a silver electrometer formed from a reference electrode consisting of an Ag / AgCl electrode in an ol / L solution.

Organic silver salt (see Table 3) An amount that gives a silver amount of 1.6 g / m ² Binder (total amount of the polymer part of the polymer silver salt of the present invention and copoly (styrene-butadiene) latex) 6. 0 g / m ² sensitizing dye -1 1.8 mg / m ² antifoggant -1: pyridinium hydrobromide perbromide 0.27 mg / m ² antifoggant -2 1.0 mg / m ² antifoggant -3: 2 Tribromomethylsulfonylquinoline 100 mg / m ² phthalazone 330 mg / m ² A-4 1000 mg / m ² The thickness of the image forming layer was 7 μm when a polymer silver salt was used as the organic silver salt, and behenic acid was used. Those using silver had a thickness of 15 μm.

Surface protective layer: A coating solution was prepared by adding water to an aqueous solution or aqueous dispersion of the following composition.

Gelatin 2.0 g / m ² Phthalazine 1.0 g / m ² 4-Methylphthalic acid 0.70 g / m ² Tetrachlorophthalic acid 0.20 g / m ² Tetrachlorophthalic anhydride 0.47 g / m ² 1 2,3-bis (vinylsulfonyl) -2-hydroxypropane 0.022 g / m ² silica matting agent (average particle size 2 μm) 0.5 g / m ² silica matting agent (average particle size 5 μm) 0.3 g / m ² << Evaluation of Silver Potential of Thermal Developing Material >> The thermal developing material 10000 mm ² prepared above was finely chopped into 100 mm ² size, and the whole amount was water / methanol (70/30) solution kept at 40 ° C. in a 200 ml beaker. It was immersed in 100 ml for 60 minutes. After removing the heat-developable material, the silver potential was measured using the same silver electrometer as used for the measurement of the coating solution, while maintaining the solution temperature at 40 ° C. Example 1
The photographic performance was evaluated in the same manner as described above. Table 3 shows the evaluation results.

[0136]

[Table 3]

As is clear from Table 3, the heat-developable material according to the present invention showed good results in high-humidity storage.
Use of a polymer silver salt as the organic silver salt is preferable because the thickness of the image forming layer can be reduced while maintaining good storage stability.

Example 3 [Production of photographic support] 0.170 (Konica Corporation)
8 W / m on both sides of a 175 μm-thick PET film colored blue with a densitometer PDA-65
^{A 2} -minute corona discharge treatment was performed.

(Preparation of Photosensitive Silver Halide Emulsion C) A1 Phenylcarbamoylated gelatin 88.3 g Compound (A) (10% aqueous methanol solution) 10 ml Potassium bromide 0.32 g Finished to 5429 ml with water B1 0.67 N silver nitrate aqueous solution 2635 ml C1 potassium bromide 51.55 g potassium iodide 1.47 g make up to 660 ml with water D1 potassium bromide 154.9 g potassium iodide 4.41 g iridium chloride (1% solution) 0.93 ml make up to 1982 ml with water E10. 4N Aqueous potassium bromide solution Amount required to control to pAg 8.09 F1 Potassium hydroxide 0.71 g Make up to 20 ml with water G1 56% acetic acid aqueous solution 18.0 ml H1 1.72 g anhydrous sodium carbonate Make up to 151 ml with water Compound ( A): HO (CH ₂ CH ₂ O) _n (CH (CH ₃ )
CH ₂ O) ₁₇ (CH ₂ CH ₂ O) _m H (m + n = 5 to 7) The solution (B1) was added to the solution (A1) using a mixing stirrer shown in JP-B-58-58288 and JP-B-58-58289.
を amount and the whole amount of the solution (C1) at a temperature of 45 ° C. and pAg
While controlling at 8.09, the mixture was added by the simultaneous mixing method in 4 minutes and 45 seconds to form nuclei. One minute later, the solution (F
The whole amount of 1) was added. After 6 minutes, 3/4 of the solution (B1) and the total amount of the solution (D1) were controlled at a temperature of 45 ° C. and a pAg of 8.09 by the solution (E1) for 14 minutes and 15 seconds by the double jet method. Was added. After stirring for 5 minutes, the temperature was lowered to 40 ° C., and the whole amount of the solution (G1) was added.
The silver halide emulsion was allowed to settle. 2000 ml of sedimentation part
Remove the supernatant, leaving 10 liters of water,
After stirring, the silver halide emulsion was precipitated again. The supernatant was removed, leaving 1500 ml of sedimentation, and 1 ml of water was added.
After adding 0 liter and stirring, the silver halide emulsion was sedimented. After removing the supernatant, leaving 1500 ml of the sedimented portion, the solution (H1) was added, and the temperature was raised to 60 ° C.
Stirred for 0 minutes. Finally, the pH was adjusted to 5.8, and water was added so as to be 1161 g per mol of silver, whereby photosensitive silver halide emulsion C was obtained.

This emulsion had an average grain size of 0.058 μm.
m, coefficient of variation of particle size 12%, [100] face ratio 9
It was 2% monodispersed cubic silver iodobromide grains.

(Preparation of photosensitive emulsion dispersion C) 4720 m
217.6 g of behenic acid and arachidic acid in 28 l of pure water.
2 g and stearic acid 6.4 g were dissolved at 90 ° C. Next, 93.3 ml of 4 mol / L-NaOH was added and cooled to 40 ° C. to obtain a fatty acid sodium solution. With the fatty acid sodium solution kept at 40 ° C., 45.3 g of photosensitive silver halide emulsion C and 450 ml of pure water were added and stirred for 5 minutes.

Next, a 12.6 mol / L silver nitrate solution 702.6 was prepared.
ml was added over 2 minutes and stirred for 10 minutes to obtain an organic silver salt dispersion. Thereafter, the obtained organic silver salt dispersion was transferred to a water washing container, deionized water was added thereto, and the mixture was stirred and allowed to stand. Then, the organic silver salt dispersion was floated and separated to remove lower water-soluble salts. After that, washing with deionized water and draining are repeated until the conductivity of the waste water becomes 2 μS / cm, and after centrifugal dehydration, drying is performed at 40 ° C. with a hot-air circulating dryer until there is no weight loss. A powdered organic silver salt was obtained.

Polyvinyl butyral powder (Monsan
Tova, Butvar B-79) (14.57 g) was dissolved in methyl ethyl ketone (1457 g), and VMA-GET was added.
ZMANNN DISPERMAT CA-
While stirring with a 40M type, the powdered organic silver salt 5 obtained above was
A preliminary dispersion was prepared by gradually adding 00 g and mixing well. Using a GM-2 type pressure homogenizer (manufactured by SMT Corporation), the preliminary dispersion obtained above was dispersed in two passes to prepare a photosensitive emulsion dispersion C.

(Preparation of Photosensitive Emulsion Dispersions D-1 to D-4) The polymers shown in Table 1 were weighed out so as to have a solid content corresponding to 0.7 mol of the acid group, and 1.5 mol of the polymer was obtained.
/ L sodium hydroxide solution, concentrated nitric acid and pure water
5000 ml of H5.9 solution was prepared. Liquid temperature 30 ° C
, 45.3 g of the above-mentioned photosensitive silver halide emulsion C and 450 ml of pure water were added, and the mixture was stirred for 5 minutes.

Next, a 1 mol / L silver nitrate solution 702.6
ml was added over 2 minutes and stirred for 10 minutes to obtain an organic silver salt dispersion. Thereafter, the obtained organic silver salt dispersion was transferred to a water washing container, deionized water was added thereto, and the mixture was stirred and allowed to stand. Then, the organic silver salt dispersion was floated and separated to remove lower water-soluble salts. After that, washing with deionized water and draining are repeated until the conductivity of the waste water becomes 2 μS / cm, and after centrifugal dehydration, drying is performed at 40 ° C. with a hot-air circulating dryer until there is no weight loss. A powdered organic silver salt was obtained.

Polyvinyl butyral powder (Monsan
Tova, Butvar B-79) (14.57 g) was dissolved in methyl ethyl ketone (1457 g), and VMA-GET was added.
ZMANNN DISPERMAT CA-
The powdered organic silver salt 50 obtained above was stirred with a 40M mold.
A preliminary dispersion was prepared by gradually adding 0 g and thoroughly mixing.

Using a GM-2 type pressure homogenizer (manufactured by SMT Corporation), the preliminary dispersion obtained above was dispersed in two passes to prepare photosensitive emulsion dispersions D-1 to D-4.

(Preparation of Coating Solution for Image Forming Layer) 500 g of each of the above-described photosensitive emulsion dispersions and 100 parts of methyl ethyl ketone
g was kept at 21 ° C. with stirring. Thereafter, the following additives were added in an inert gas atmosphere to prepare an image forming layer coating solution.

Pyridinium hydrobromide perbromide (PHP, 0.45 g) was added and stirred for 1 hour. Further, calcium bromide (10% methanol solution 3.25m
l) was added and stirred for 30 minutes.

Next, the infrared sensitizing dye 1, 4-chloro-2-benzoylbenzoic acid and a supersensitizer (5-methyl-2
-Mercaptobenzimidazole) (mixing ratio 1: 250: 20, 0.1% methanol solution with sensitizing dye, 7 ml), and stirred for 1 hour.
The temperature is lowered to 3 ° C. and the mixture is further stirred for 30 minutes. While keeping the temperature at 13 ° C., polyvinyl butyral (Butvar B-79 manufactured by Monsanto) was added and dissolved sufficiently, and then the following additives were sequentially added to obtain a photosensitive layer coating solution.

(1,1-bis (2-hydroxy-3,5-dimethylphenyl) -2-methylpropane) 15 g Desmodur N3300 (aliphatic isocyanate manufactured by Mobay) 1.10 g Phthalazine 1.5 g Tetrachlorophthalic acid 0.5 g 4-methylphthalic acid 0.5 g (Preparation of coating solution for surface protective layer) Methyl ethyl ketone 865
g of cellulose acetate butyrate (CAB171-Eastman Chemical Co.)
15) 96 g and 4.5 g of polymethyl methacrylic acid (Paraloid A-21 manufactured by Rohm & Haas) were added and dissolved. 1,3-bis (vinylsulfonyl) -2-
1.5 g of hydroxypropane, 1.0 g of benzotriazole, silica (Fuji Silysia Syloid 320)
1.6 g and fluorine-based activator (Surflon K manufactured by Asahi Glass Co., Ltd.)
H40) (1.0 g) was added and dissolved to prepare a surface protective layer coating solution.

(Preparation of Protective Lower Layer Coating Solution) Polyvinyl butyral powder (Butvar B-79 manufactured by Monsanto) 6 was stirred with 665 g of methyl ethyl ketone.
5 g and 3.5 g of polymethyl methacrylic acid (Rohm & Haas Co., Ltd., Paraloid A-21) were added and dissolved. To this solution, 4.5 g of 1,3-bis (vinylsulfonyl) -2-hydroxypropane, 3.0 g of benzotriazole and 1.6 g of silica (Fuji Silysia Syloid 320) were added and dissolved to prepare a coating solution for a protective lower layer. did.

(Coating on the Image Forming Layer Surface Side)
Prepared image forming layer coating solution and protective lower layer coating solution, surface protection
Using the protective layer coating solution, the dry thickness of the image forming layer is 7 μm,
Lower layer dry thickness 1 μm, surface protective layer dry thickness 1 μm
On the support in this order, simultaneously coat each layer in this order.
This was performed at 75 ° C. for 5 minutes to prepare a heat developing material. In addition,
The amount of cloth silver is 1.6 g / m ^TwoIs adjusted so that
Organic acid silver salt of image forming layer / (organic acid silver salt + polyvinyl butyral)
Lar) The mass ratio is 70% by mass or more for all samples.
there were.

(Preparation of Back Surface Coating Solution) Cellulose acetate butyrate (CAB manufactured by Eastman Chemical Company) was stirred with 830 g of methyl ethyl ketone.
381-20) 84.2 g, polyester resin (Bos
4.5 g of Vitec PE2200B (trade name, manufactured by tic) was added and dissolved. 0.30 g of infrared dye 1 was added to the dissolved solution, and 4.5 g of a fluorine-based activator (Surflon KH40 manufactured by Asahi Glass Co., Ltd.) and 4 g of a fluorine-based activator (Megafag manufactured by Dainippon Ink and Chemicals) dissolved in 43.2 g of methanol. F120
K) 2.3 g was added, and the mixture was sufficiently stirred until dissolved. Finally, silica (W.A.) dispersed in methyl ethyl ketone at a concentration of 1% by mass with a dissolver-type homogenizer.
R. Grace, 64x6000 thyroid)
g was added and stirred to prepare a coating solution for the back surface.

(Coating of Back Surface) The thus prepared back surface coating solution was applied and dried on the sample prepared above by an extrusion coater so that the dry film thickness became 3.5 μm. Drying was performed for 5 minutes using a drying air having a drying temperature of 100 ° C. and a dew point of 10 ° C.

The total amount of the residual solvent contained in the light-sensitive material prepared as described above was 130 mg / m ² .

<< Evaluation of Silver Potential of Thermal Developing Material >> The thermal developing material 10000 mm ² prepared above was finely cut into a size of 100 mm ² , and the total amount was reduced to 40 ml in a 200 ml beaker.
Water / methanol (70/30) liquid 100 kept at 100 ° C
The sample was immersed in the solution for 60 minutes. After removing the heat-developable material, the silver potential was measured using the same silver electrometer as used for the measurement of the coating solution, while maintaining the solution temperature at 40 ° C. The photographic performance of the sample prepared as described above was evaluated in the same manner as in Example 1.

[0158]

Embedded image

[0159]

[Table 4]

As is clear from Table 4, the sample according to the present invention showed good results in high-humidity storage. Also,
Good results were obtained even when the image forming layer was as thin as 7 μm.

[0161]

As is clear from the results of the examples, the present invention enables the image forming layer to be applied without using an organic solvent which is harmful to the environment and the human body and which is disadvantageous in cost. It was possible to provide a heat-developable material with high sensitivity and low fog even when stored at high humidity even when thin.

Claims (11)

[Claims] 1. A support, and photosensitive silver halide grains,
In a heat-developable material comprising an image forming layer containing an organic silver salt, 10,000 mm ² of the heat-developable material is mixed with 100 ml of a liquid dispersion medium containing 30% by mass or more of water at 40 ° C.
After immersion for 0 minutes, when the thermal developing material is removed,
A heat-developable material, wherein the liquid potential of the liquid dispersion medium at 40 ° C. is 200 mV or less. 2. The heat-developable material according to claim 1, wherein the image forming layer or the constituent layer contains a reducing agent or a reducing agent precursor. 3. The image forming layer is formed by applying and drying a coating liquid having a silver potential of 200 mV or less, wherein water accounts for 30% by mass or more of the liquid dispersion medium. 2. The heat-developable material according to item 1. 4. The heat-developable material according to claim 1, wherein the image forming layer is formed by coating and drying using a coating liquid in which 30% by mass or more of the liquid dispersion medium is an organic solvent. 5. The heat developing material according to claim 1, wherein the organic silver salt is a silver salt with a polymer represented by the following general formula (1). Formula (1)-(A) _a- (B) _b- (where A represents a repeating unit derived from a monomer having an acid group, and B represents a repeating unit derived from a monomer other than A. a and b represent a copolymerization ratio, and a is 5 to 9
5 mass% and b is 5 to 95 mass%. Where a + b =
100% by mass. ) 6. The heat developing material according to claim 5, wherein 95% or more of the acid groups of the polymer form an organic silver salt. 7. The photothermographic material according to claim 5, wherein the acid group is a carboxyl group. 8. The photothermographic material according to claim 1, wherein the organic silver salt is a silver salt of a polymer formed by polyaddition of a mixture containing at least a carboxyl group-containing dihydroxy compound and a diisocyanate compound. 9. The photothermographic material according to claim 5, wherein the organic silver salt is contained in an amount of 50% by mass or more of the image forming layer, and the binder is contained in an amount of 50% by mass or less of the image forming layer. 10. The photothermographic material according to claim 9, wherein the thickness of the image forming layer is 1 to 10 μm. 11. The image forming layer according to claim 1, wherein the image forming layer is formed by applying a coating liquid comprising an organic silver salt and a liquid dispersion medium containing 30% by mass or more of water as a coating liquid. A method for producing a heat developing material.