JP2002258440A - Method for producing heat developable photosensitive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat developable photosensitive material having high- contrast gradation and good dot quality and less liable to increase fog in storage at high temperature and less liable to generate black spots. SOLUTION: In the method for producing the heat developable photosensitive material having a non-photosensitive organic silver salt, photosensitive silver halide, a reducing agent for silver ions, a binder and a compound imagewise generating a chemical species capable of forming development starting points on the non-photosensitive organic silver salt and in its vicinities on one face of the base, when a layer containing the compound imagewise generating the chemical species is formed on the base, the compound is added to a coating liquid as a dispersion of solid fine particles having 0.05-1.0 μm average particle diameter and including <=5 vol.% particles each having >=3 μm particle diameter and the resulting coating liquid is applied and dried.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a photothermographic material, and more particularly to a photothermographic material for scanners and imagesetters suitable for photolithography.
More particularly, the present invention relates to a method for producing a photothermographic material having a high gradation, good halftone dot quality, small fog increase during high-temperature storage, and less occurrence of black spots.

[0002]

2. Description of the Related Art A photosensitive image forming layer is provided on a support,
Many photosensitive materials that form an image by image exposure are known. Among them, there is a technique of forming an image by thermal development as a system that contributes to environmental conservation and can simplify an image forming unit. In recent years, in the field of photoengraving, it has been strongly desired to reduce the amount of processing waste liquid from the viewpoint of environmental conservation and space saving. Therefore, there is a need to develop a technology relating to a photothermographic material for photolithography, which can be efficiently exposed by a laser scanner or a laser imagesetter and can form a sharp black image having high resolution and sharpness. is needed. According to such a photothermographic material, it is possible to supply a customer with a simpler and more environmentally friendly photothermographic processing system which does not require a solution processing chemical.

A method of forming an image by thermal development is described in, for example, US Pat. Nos. 3,152,904 and 3,4,904.
57,075, and D.C. Crosta Bohr (Kl
"Thermally Processed Silver Systems A" (Imaging Processes and Materials (Imag)
ing Processes and Materials) Neblette 8th edition,
J. Sturge, V.S. Walworth
th), A. Edited by Shepp, Chapter 9 Chapter 279
1989). Such photothermographic materials typically contain 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 an organic binder matrix. It is contained in a state. The photosensitive material is stable at room 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 formed by the exposure. The silver formed by the reaction of the reducible silver salt in the exposed areas becomes black and forms an image because it contrasts with the unexposed areas.

Conventionally known photothermographic materials are:
In many cases, the image forming layer is formed by applying a coating solution using an organic solvent such as toluene, methyl ethyl ketone (MEK) or methanol as a solvent. The use of an organic solvent as a solvent not only adversely affects the human body in the manufacturing process, but also disadvantageous in cost because a solvent recovery and other steps are required. Then, a method of forming an image forming layer using a coating solution using water as a solvent has been proposed.
For example, JP-A-49-52626 and JP-A-53-1
No. 16144 discloses an image forming layer using gelatin as a binder. Japanese Patent Laid-Open No. 50-15
Japanese Patent No. 1138 describes an image forming layer using polyvinyl alcohol as a binder. Furthermore, Japanese Unexamined Patent Publication No.
Japanese Patent Application Laid-Open No. 0-61747 describes an image forming layer using gelatin and polyvinyl alcohol in combination. As another example, JP-A-58-28737 describes an image forming layer using a water-soluble polyvinyl acetal as a binder. With such a binder,
Since the image forming layer can be formed using a coating solution of a water solvent, the environmental and cost advantages are great.

However, when a polymer such as polyvinyl alcohol or water-soluble polyacetal is used as a binder, the silver tone of the developed part becomes brown or yellow, which is far from black which is originally preferable, and the blackening density of the exposed part is low. However, there was a problem that the density of the unexposed portion was high, and only those having a significantly impaired commercial value were obtained. In addition, the above-mentioned thermal developing system has a problem that the halftone dot quality is inferior to that of a conventional chemically processed light-sensitive material. Furthermore, sand-like fog (black spots) generated in unexposed areas is easily generated, and improvement has been desired. In addition, in the organic silver salt type photothermographic material, chemicals such as an organic silver salt and a reducing agent remain as they are in a non-image area (unexposed area) after development, so that a car in summer can be used. There is a problem that the development progresses gradually and the Dmin rises during high-temperature storage, such as during storage. For this reason,
Provided is a photothermographic material which has a hard gradation with a binder used in the above-mentioned aqueous solvent coating solution, has good halftone dot quality, has a small rise in fog during high-temperature storage, and hardly generates black spots. Was desired.

[0006]

A first object of the present invention is to provide a photothermographic material for photolithography, particularly for a scanner or an image setter, which has a high gradation and a halftone dot quality. It is an object of the present invention to provide a method for producing a photothermographic material, which has a good image quality, has a small rise in fog during high-temperature storage, and hardly generates black spots. A second object of the present invention is to provide a method for producing a photothermographic material which can be applied in water and which is advantageous in terms of environment and cost.

[0007]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a non-photosensitive organic silver salt,
Photothermographic material containing photosensitive silver halide, a reducing agent for silver ions, a binder, and a compound capable of imagewise generating a chemical species capable of forming a development start point on and near a non-photosensitive organic silver salt When a layer containing a compound capable of imagewise generating a chemical species capable of forming a development start point on and near a non-photosensitive organic silver salt is formed on a support, the compound is formed by the following method. It has been found that the object can be solved by the method for producing a photothermographic material of the present invention, which comprises adding a solid fine particle dispersion satisfying both conditions to a coating solution, coating and drying the coating solution. (1) The average particle diameter is 0.05 μm to 1.0 μm (2) The volume ratio of particles having a particle diameter of 3 μm or more is 5% or less In the method for producing a photothermographic material of the present invention, the non-photosensitive organic silver salt is used. Instead of a compound capable of forming a chemical species capable of forming a development start point on and near the image in an image-wise manner, 0.01 m
ol / silver compound that increases the density of developed silver particles to 200 to 5000% by adding
It is also effective to use a compound whose covering power increases to 120 to 1000% by adding 1 mol / mol of silver. In the method for producing a photothermographic material of the present invention, it is desirable that the solid fine particle dispersion contains a preservative, preferably at a preservative concentration of 500 ppm or less. In the method for producing a photothermographic material according to the present invention, before adding the solid fine particle dispersion to the coating solution, 85% or more, preferably 98% or more, of the coarse particles having a particle diameter of 3 μm or more present in the solid fine particle dispersion. % Or more is desirably removed by filtration.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for producing a photothermographic material of the present invention will be described in detail. In this specification, “to” indicates a range including numerical values described before and after it as a minimum value and a maximum value, respectively. First,
A compound which is used in the method for producing a photothermographic material of the present invention and which produces a chemical species capable of forming a development start point on and near a non-photosensitive organic silver salt in an image-wise manner, 0.01
mol / silver compound that increases the density of developed silver particles to 200 to 5000% by adding
Compounds that increase the covering power to 120 to 1000% by adding ol / mol of silver will be described. In addition, in this specification, the compound corresponding to any of these to is referred to as “the compound of the present invention”.

First, a compound capable of forming a chemical species capable of forming a development start point on and near a non-photosensitive organic silver salt in an image-wise manner will be described. When the compound is not present in the light-sensitive material, physical development proceeds only on the silver halide on which a latent image has been formed by exposure. When a compound of the formula (1) is present in the photosensitive material, the chemical species generated with physical development occurring on the silver halide on which the latent image has been formed by exposure to light, such as a compound with an oxidized developing agent, reacts to form a non-photosensitive material. Chemical species capable of forming a development start point are formed on and near the organic silver salt. The species form a development starting point on and near a non-photosensitive silver salt, such as silver behenate, from which physical development occurs. That is, when the compound of the present invention is present in the light-sensitive material, physical properties are present both on the silver halide on which a latent image is formed by exposure and on and near the non-photosensitive organic silver salt on which an image-wise development start point is formed. Development proceeds.

FIG. 1 shows that the photosensitive material after development was cut to a thickness of 2 μm in both cases where the compound was present in the photosensitive material at 0.01 mol / silver mol (A) and not present (B). This is the result of taking an electron micrograph of the slice. The photothermographic materials targeted for photography were
Experiment No. in Example 1 of Japanese Patent Application No. 2000-393931. 1 photothermographic material (Japanese Patent Application No. 2001-39)
Experiment No. 0779 in Example 1 of the specification of US Pat. 1 is the same as that of the photothermographic material of Example 1).
Performed as described in. It is apparent from FIG. 1 that the number of developed silver particles was greatly increased by adding the compound of the present invention.

Next, a compound which increases the density of developed silver particles to 200 to 5000% by adding 0.01 mol / mol of silver will be described. The amount of increase in the density of developed silver particles was determined by taking a photograph as shown in FIG. 1 above for a sample in which all silver ions in the photosensitive material were reduced, counting the number of developed silver particles per unit area, and measuring the density. Can be obtained by comparing When the compound of the present invention is present in the light-sensitive material, the developed silver particle density is 200 to 500 as compared with the case where the compound is not present in the light-sensitive material.
Increase to 0%. A more preferred compound has a developed silver particle density increase rate of 500 to 3000%.

Next, by adding 0.01 mol / mol of silver, the covering power becomes 120 to 1000%.
The compound which increases to will be described. As used herein, the term "covering power" refers to a value obtained by dividing the visible density by the amount of developed silver (g / m ² ) for a sample in which all silver ions in the photosensitive material have been reduced. The increase of the covering power by the compound of the present invention is shown in FIGS. 1 (A) and 1 (B).
As can be seen from the comparison, a large number of smaller developed silver particles are formed. The covering power of the compound is more preferably from 150 to 500%.

Next, as a specific example of the compound of the present invention corresponding to any of the above-mentioned, JP-A-2000-2843
No. 99, the hydrazine derivatives represented by the formula (H) (specifically, the hydrazine derivatives described in Tables 1 to 4 of the same specification), JP-A-10-10672, JP-A-10-10672
JP-A-161270, JP-A-10-62898, JP-A-9-304870, JP-A-9-304
No. 872, JP-A-9-304871, JP-A-10-31282, U.S. Pat. No. 5,496,69
5, all hydrazine derivatives described in European Patent Publication No. EP 741,320A;
No. 84399, substituted alkene derivatives represented by the formulas (1) to (3), substituted isoxazole derivatives and specific acetal compounds, and further represented by the formula (A) or the formula (B) described in the same specification. The cyclic compounds represented by the compounds, specifically, compounds 1 to 72 described in Chemical Formulas 8 to 12 of the same specification can be exemplified.

The compound of the present invention is described in JP-A-11-1.
The compound represented by the general formula (1) described in JP-A-49136 is more preferably used. Specific examples of the compound represented by the general formula (1) are shown below.

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

[Table 3]

[0018]

[Table 4]

[0019]

[Table 5]

[0020]

[Table 6]

[0021]

[Table 7]

[0022]

[Table 8]

[0023]

[Table 9]

[0024]

[Table 10]

[0025]

[Table 11]

[0026]

[Table 12]

Further, formic acid precursors described in Japanese Patent Application No. 2000-313207 are also preferably used. Specific examples of the compound are shown below.

[0028]

Embedded image The above-mentioned compound of the present invention is preferably water-insoluble (the solubility in water at 25 ° C. is 0.1% or less).

The water-insoluble organic compound is added to the photosensitive material as a solid dispersion of fine powder (fine crystal particles). A fine (crystalline) particle solid dispersion of the compound may be prepared by using a suitable solvent (water, alcohol, or the like), if necessary, in the presence of a dispersing agent, using a known pulverizing means (for example, ball mill, vibrating ball mill, planetary ball mill, Sand mill, colloid mill, jet mill, roller mill, microfluidizer)
Can be prepared mechanically. As the solvent, water is preferably used in an amount of 90% or more, more preferably 95% or more.

Further, fine (crystal) particles of the compound are prepared by dissolving the compound in a suitable solvent using a dispersing aid and then adding the compound to a poor solvent for the compound to precipitate fine crystals. Alternatively, a solid dispersion can be obtained by controlling the pH, dissolving the compound first, and then changing the pH to perform microcrystallization. At this time, an organic solvent may be used as a solvent used for the coarse dispersion, and the organic solvent is usually removed after completion of the fine particle formation.

As the dispersing aid, any surfactant such as nonionic, anionic, cationic and fluorine-based surfactants can be used as appropriate. Anionic, nonionic and amphoteric surfactants are preferred, and the use of anionic and / or nonionic surfactants is particularly preferred. Specifically, Japanese Patent Application Laid-Open No. Sho 62
-170950, U.S. Pat. No. 5,380,644, etc. Fluorinated polymer surfactants described in JP-A-60-244945 and JP-A-63-188135.
US Patent No.
Examples include polysiloxane surfactants described in 885,965 and the like, polyalkylene oxides and anionic surfactants described in JP-A-6-301140 and the like.

The compound of the present invention is added to a coating solution as a solid fine particle dispersion. The average particle diameter of the fine particles in the general dispersion is 0.05 μm to 1.0 μm or less, and the volume ratio of the particles having a particle diameter of 3 μm or more to all the fine particles in the dispersion is 5% or less. Preferably, the volume ratio of the particles having a particle diameter of 3 μm or more is 1% or less. The compound of the present invention added as a solid fine particle dispersion is present in the light-sensitive material in the form of solid fine particles.

The particle size distribution of the dispersion is preferably monodisperse. Specifically, the percentage (coefficient of variation) of the value obtained by dividing the standard deviation of the volume load average diameter by the volume load average diameter is preferably 80% or less, more preferably 50% or less, and more preferably 30% or less. Is particularly preferred. In the present invention, the average particle diameter (volume-weighted average diameter) and the volume ratio of particles having a particle diameter of 3 μm or more were measured using a laser diffraction / scattering particle size distribution analyzer SALD2000 (manufactured by Shimadzu Corporation).

Further, in the present invention, before adding the solid fine particle dispersion to the coating solution, the particle diameter of the solid fine particle dispersion existing in the dispersion is 3 μm.
It is preferable that at least 85% of the above coarse particles are removed by filtration, and 98% of the coarse particles having a particle size of 3 μm or more.
More preferably, the above is removed by filtration.
Specifically, AstroPore-PPE10 using a polypropylene nonwoven fabric having a pore diameter of 10 μm as a filter medium.
(Fuji Photo Film) can be used to remove 85% or more of the coarse particles having a particle size of 3 μm or more. 3μ
98% or more of the coarse particles of m or more can be removed.

In the present invention, it is preferable to add a preservative to the solid dispersion. The preservative concentration in the solid dispersion is preferably 500 ppm or less,
pm or less. As the preservative, a known compound can be used. As the preservative that is preferably used, a compound represented by the general formula (B) described in JP-A-2001-83657 is exemplified. Specific examples include compounds I-1 to I-20 described in the same specification. Furthermore, compounds represented by the general formulas (II) and (III) described in Patent Registration No. 2843867, specifically, the compounds II-1 to II- described in the same specification
6, III-1 to III-7 can also be preferably used as preservatives.

The compound of the present invention, even when used alone,
More than one species may be used in combination. The compound of the present invention may be added to any layer on the image forming layer side with respect to the support,
It is preferably added to the image forming layer or a layer adjacent thereto. The addition amount of the compound of the present invention is preferably 1 × 10 ⁻⁶ to 1 mol per 1 mol of silver, and 1 × 10 ^{−5 to} 5 ×.
10 ^-1 mol is more preferred, and 2 x 10 ^-5 to 2 x 10 ^-1.
mol is most preferred.

In the photothermographic material of the present invention, an acid or a salt thereof formed by hydration of diphosphorus pentoxide is preferably used in combination with the compound of the present invention. Acids or salts thereof formed by hydration of diphosphorus pentoxide include metaphosphoric acid (salt), pyrophosphoric acid (salt), orthophosphoric acid (salt), triphosphoric acid (salt), tetraphosphoric acid (salt), hexametaline Acids (salts) and the like can be mentioned. Particularly preferred acids and salts thereof formed by hydration of diphosphorus pentoxide include orthophosphoric acid (salt) and hexametaphosphoric acid (salt). Specific salts include sodium orthophosphate, sodium dihydrogen orthophosphate, sodium hexametaphosphate, ammonium hexametaphosphate and the like. The acid or salt thereof formed by hydration of diphosphorus pentoxide, which can be preferably used in the present invention, is added to the image forming layer or the binder layer adjacent thereto in that the desired effect is exhibited in a small amount. The amount of acid or salt thereof formed by hydration of diphosphorus pentoxide (1 m ^{2 of} photosensitive material)
The coating amount per) is may be desired amount depending on the performance such as sensitivity and fog, preferably ^{0.1~500mg / m 2, 0.5~100mg / m} 2 is more preferable.

The organic silver salt that can be used in the present invention includes:
Relatively stable to light, but forms a silver image when heated to 80 ° C. or higher in the presence of an exposed photocatalyst (such as a latent image of photosensitive silver halide) and a reducing agent It is a silver salt. The organic silver salt can be any organic material including a source of reducible silver ions. Silver salts of organic acids, particularly silver salts of long-chain fatty carboxylic acids (preferably having 10 to 30 carbon atoms, more preferably 15 to 28 carbon atoms) 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.
The silver donor material can preferably comprise about 5 to 70% by weight of the imaging layer. As a preferred organic silver salt,
A silver salt of an organic compound having a carboxyl group can be mentioned. Specific examples thereof include silver salts of aliphatic carboxylic acids and silver salts of aromatic carboxylic acids, but are not limited thereto. Preferred examples of the silver salt of an aliphatic carboxylic acid include silver behenate, silver arachidate,
Silver stearate, silver oleate, silver laurate, silver caproate, silver myristate, silver palmitate, silver maleate, silver fumarate, silver tartrate, silver linoleate, silver butyrate and silver camphorate, mixtures thereof, etc. Can be mentioned.

In the present invention, in the above-mentioned organic acid silver or a mixture of the organic acid silver, a silver behenate content of 75 m
ol% or more of organic acid silver, more preferably 85% by mole or more of silver behenate. Here, the content of silver behenate indicates the mole fraction of silver behenate with respect to the organic acid silver used. As the organic acid silver other than silver behenate contained in the organic acid silver used in the present invention, the above-mentioned exemplified organic acid silver can be preferably used.

The organic acid silver which is preferably used in the present invention is
It is prepared by reacting silver nitrate with a solution or suspension of the above-mentioned alkali metal salt of an organic acid (including Na salt, K salt, Li salt and the like). These preparation methods are described in JP-A-2000-292882, paragraph number 00.
19 to 0021 can be used.

In the present invention, a method for preparing an organic silver salt by adding an aqueous solution of silver nitrate and a solution of an alkali metal salt of an organic acid into a sealing means for mixing a liquid can be preferably used. Specifically, JP-A-200
The method described in 1-333907 can be used. In the present invention, a water-soluble dispersant can be added to the aqueous silver nitrate solution and the organic acid alkali metal salt solution or the reaction solution during the preparation of the organic acid silver.
Specific examples of the type and amount of the dispersant used here are described in JP-A-2000-305214, paragraph 0052.

The organic acid silver used in the present invention is preferably prepared in the presence of a tertiary alcohol. As the tertiary alcohol, compounds having a total carbon number of 15 or less are preferable, and compounds having a total carbon number of 10 or less are particularly preferable. Examples of preferred tertiary alcohols include tert-butanol and the like,
The tertiary alcohol that can be used in the present invention is not limited to this. The timing of adding the tertiary alcohol used in the present invention may be any timing at the time of preparing the organic acid silver,
It is preferable to add and dissolve the organic acid alkali metal salt during the preparation of the organic acid alkali metal salt. The tertiary alcohol used in the present invention can be used in a weight ratio of 0.01 to 10 with respect to water as a solvent at the time of preparing the silver salt of an organic acid. It is preferred to use.

The shape and size of the organic silver salt which can be used in the present invention are not particularly limited.
It is preferable to use those described in paragraph No. 0024 of No. 2882. The shape of the organic silver salt can be determined from a transmission electron microscope image of the organic silver salt dispersion. Another method for measuring monodispersity is to determine the standard deviation of the volume-weighted average diameter of the organic silver salt. The percentage (coefficient of variation) divided by the volume-weighted average diameter is preferably 80% or less, more preferably Preferably 50% or less, more preferably 30%
% Or less. As a measuring method, for example, an organic silver salt dispersed in a liquid is irradiated with laser light, and the particle size (volume weighted average diameter) obtained by obtaining an autocorrelation function with respect to a time change of fluctuation of the scattered light is obtained. be able to. The average particle size in this measurement method is 0.1.
A solid fine particle dispersion of from 0.05 μm to 10.0 μm is preferred. A more preferred average particle size is 0.1 μm to 5.0.
μm, more preferably the average particle size is from 0.1 μm
2.0 μm.

The organic silver salt used in the present invention is preferably desalted. The desalting method is not particularly limited, and a known method can be used, but centrifugal filtration, suction filtration,
Known filtration methods such as ultrafiltration and floc-forming water washing by a coagulation method can be preferably used. As a method of ultrafiltration, a method described in JP-A-2000-305214 can be used.

In the present invention, in order to obtain a solid dispersion of an organic silver salt having a high S / N, a small particle size and no aggregation, an organic silver salt which is an image forming medium and a photosensitive silver salt are substantially contained. It is preferable to use a dispersion method in which a water dispersion liquid which is not included in the liquid is converted into a high-speed stream and then the pressure is reduced. As for these dispersing methods, the methods described in paragraphs 0027 to 0038 of JP-A-2000-292882 can be used.

The particle size distribution of the organic silver salt solid fine particle dispersion used in the present invention is preferably monodispersed. Specifically, the percentage (coefficient of variation) of the value obtained by dividing the standard deviation of the volume load average diameter by the volume load average diameter is preferably 80% or less, more preferably 50% or less, and more preferably 30% or less. Is more preferable.

The organic silver salt solid fine particle dispersion used in the present invention comprises at least an organic silver salt and water. The ratio between the organic silver salt and water is not particularly limited, but the ratio of the organic silver salt to the whole is preferably 5 to 50% by mass, and particularly preferably 10 to 30% by mass.
It is preferable to use the above-mentioned dispersing aid, but it is preferable to use the dispersing aid in a minimum amount within a range suitable for minimizing the particle size.
A range of 15% by mass is preferred.

The organic silver salt used in the present invention can be used in a desired amount, but the silver amount is preferably 0.1 to 5 g / m ² .
More preferably, it is 1-3 g / m < ² >.

In the present invention, it is preferable to add a metal ion selected from Ca, Mg, Zn and Ag to the non-photosensitive organic silver salt. Regarding addition of metal ions selected from Ca, Mg, Zn and Ag to the non-photosensitive organic silver salt,
It is preferably added in the form of a water-soluble metal salt which is not a halide, and specifically, it is preferably added in the form of a nitrate or a sulfate. The addition of a halide is not preferable because it deteriorates the image storability of the processed photosensitive material due to light (such as room light or sunlight), that is, the so-called printout property. For this reason, in the present invention, it is preferable to add in the form of a water-soluble metal salt which is not a halide.

Ca, Mg, Zn preferably used in the present invention
The addition time of the metal ion selected from Ag and Ag may be any time after the formation of the particles of the non-photosensitive organic silver salt and immediately before the coating, such as immediately after the formation of the particles, before the dispersion, after the dispersion and before and after the preparation of the coating solution. It may be during the period, preferably after dispersion and before and after preparation of the coating solution. Ca, M in the present invention
The addition amount of the metal ion selected from g, Zn and Ag is 10 ⁻³ to 10 ⁻¹ per 1 mol of non-photosensitive organic silver.
mol is preferable, and particularly 5 × 10 ^{−3 to} 5 × 10 ⁻² mol.
Is preferred.

The photosensitive silver halide used in the present invention is not particularly limited as a halogen composition, and may be silver chloride, silver chlorobromide,
Silver bromide, silver iodobromide, silver iodochlorobromide can be used. The grain formation of the photosensitive silver halide emulsion is described in paragraphs 0217 to 0217 of JP-A-11-119374.
The particles can be formed by the method described in H.224, but are not particularly limited to this method. The shapes of silver halide grains are cubic, octahedral, tetradecahedral,
Tabular, spherical, rod-like, potato-like and the like can be mentioned, and in the present invention, cubic particles or tabular particles are particularly preferable. The characteristics of the particle shape such as the particle aspect ratio and the surface index are described in JP-A-11-119374.
It is the same as that described in Paragraph No. 0225 of the publication. The distribution of the halogen composition may be uniform inside and on the surface of the silver halide grains, and the halogen composition may be changed stepwise or may be changed continuously. Further, silver halide grains having a core / shell structure can be preferably 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. A technique for localizing silver bromide on the surface of silver chloride or silver chlorobromide grains can also be preferably used.

The size of the silver halide grains of the photosensitive silver halide used in the present invention is not particularly limited, and may be 0.1 to 0.1.
2 μm or less is preferable, and further 0.01 to 0.10 μm
Is preferred. The particle size distribution of the silver halide grains used in the present invention is preferably such that the value of monodispersity is 30% or less, more preferably 1 to 20%, and 5 to 15%.
Is more preferable. Here, the monodispersity is defined as a percentage (%) (coefficient of variation) of a value obtained by dividing the standard deviation of the particle size by the average particle size. For the sake of convenience, the grain size of the silver halide grains is represented by a ridge length in the case of a cubic grain, and the other grains (octahedral, tetradecahedral, tabular, etc.) are calculated by the projected area circle equivalent diameter.

The photosensitive silver halide grains used in the present invention contain a metal or metal complex of Group VII or VIII of the periodic table. Rhodium, rhenium, ruthenium, osnium and iridium are preferred as the metal of Group VII or VIII of the periodic table or the central metal of the metal complex. Particularly preferred metal complexes are (N
H ₄ ) ₃ Rh (H ₂ O) Cl ₅ , K ₂ Ru (NO) Cl ₅ , K
₃ IrCl ₆ and K ₄ Fe (CN) ₆ . One type of these metal complexes may be used, or two or more types of complexes of the same metal and different metals may be used in combination. Preferred content is 1 mol of silver
Is preferably in the range of 1 × 10 ⁻⁹ mol to 1 × 10 ⁻³ mol, more preferably in the range of 1 × 10 ⁻⁸ mol to 1 × 10 ⁻⁴ mol. As a specific structure of the metal complex, a metal complex having a structure described in JP-A-7-225449 or the like can be used. The types and addition methods of these heavy metals are described in paragraphs 0227 to 0240 of JP-A-11-119374.

The photosensitive silver halide grains can be desalted by a water washing method known in the art such as a noodle method or a flocculation method, but in the present invention, it may or may not be desalted. . The photosensitive silver halide emulsion used in the present invention is preferably chemically sensitized. The chemical sensitization is described in paragraph No. 02 of JP-A-11-119374.
It is preferable to use the methods described in JP-A Nos. 42-0250. A thiosulfonic acid compound may be added to the silver halide emulsion used in the present invention by a method described in European Patent Publication EP 293,917A.

As the gelatin contained in the photosensitive silver halide used in the present invention, a low molecular weight gelatin is used in order to maintain a good dispersion state of the photosensitive silver halide emulsion in a coating solution containing an organic silver salt. Is preferred. The low molecular weight gelatin has a molecular weight of 500 to 60,000, preferably 1,000 to 40,000. These low molecular weight gelatins may be used at the time of particle formation or at the time of dispersion after desalting, but are preferably used at the time of dispersion after desalting. When forming particles, use normal gelatin (molecular weight of about 100,000),
Low-molecular-weight gelatin may be used at the time of dispersion after desalting.

The concentration of the dispersion medium can be 0.05 to 20% by mass, but a concentration range of 5 to 15% by mass is preferable for handling. As the type of gelatin, alkali-treated gelatin is usually used, and in addition, acid-treated gelatin,
Modified gelatin such as phthalated gelatin can also be used.

One type of silver halide emulsion in the light-sensitive material used in the present invention may be used alone, or two or more types thereof (for example, those having different average grain sizes, different halogen compositions, different crystal habits). And those having different chemical sensitization conditions).

The amount of the photosensitive silver halide used in the present invention is preferably 0.01 to 0.5 mol, more preferably 0.02 to 1 mol of the organic silver salt.
mol to 0.3 mol, more preferably 0.03 mol
~ 0.25 mol is particularly preferred. About the mixing method and mixing conditions of the separately prepared photosensitive silver halide and organic silver salt, the silver halide particles and the organic silver salt which have been respectively prepared are mixed with a high-speed stirrer, a ball mill, a sand mill, a colloid mill, a vibration mill, There is a method of mixing with a homogenizer or the like, 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. There is no particular limitation as long as it is sufficiently obtained. In addition, mixing two or more kinds of aqueous dispersions of organic silver salts and two or more kinds of aqueous dispersions of photosensitive silver salts is a preferable method for adjusting photographic characteristics.

The sensitizing dye which can be used in the present invention is a dye capable of spectrally sensitizing silver halide grains in a desired wavelength region when adsorbed on silver halide grains, and is suitable for the spectral characteristics of an exposure light source. Sensitizing dyes having spectral sensitivity can be advantageously selected. For example, 550 nm to 750 n
As a dye for spectrally sensitizing a wavelength region of m
And dyes represented by the general formula (II) of JP-A-186572, specifically, II-6, II-7, II-14, and II-.
Dyes 15, II-18, II-23 and II-25 can be exemplified as preferred dyes. Also, 750 to 14
Dyes that spectrally sensitize the wavelength region of 00 nm include dyes represented by the general formula (I) in JP-A-11-119374, and specifically, (25), (26), and (3)
0), (32), (36), (37), (41), (4)
The dyes of 9) and (54) can be exemplified as preferred dyes. Further, as a dye for forming a J-band, U.S. Pat.
The dyes described in Example 5 of JP-A-871,887 and the dyes disclosed in JP-A-2-96131 and JP-A-59-48753 can be exemplified as preferred dyes. These sensitizing dyes may be used alone or in combination of two or more.

These sensitizing dyes can be added by the method described in paragraph No. 0106 of JP-A-11-119374, but the method is not particularly limited. The addition amount of the sensitizing dye in the present invention can be a desired amount in accordance with the sensitivity and the performance of fogging, but is preferably 10 ^{-6 to} 1 mol, more preferably 1 to 1 mol per mol of silver halide in the photosensitive layer.
0 ^-4 to 10 ^-1 mol.

The present invention improves the spectral sensitization efficiency by
Supersensitizers can be used. Examples of the supersensitizer used in the present invention include compounds disclosed in European Patent Publication No. EP587,338A, U.S. Pat. Nos. 3,877,943 and 4,873,184.
Examples thereof include a compound selected from a heteroaromatic or aliphatic mercapto compound, a heteroaromatic disulfide compound, stilbene, hydrazine, and triazine. Particularly preferred supersensitizers include heteroaromatic mercapto compounds and heteroaromatic disulfide compounds disclosed in JP-A-5-341432, and general formula (I) or (II) in JP-A-4-182639. A stilbene compound represented by the general formula (I) in JP-A-10-111543, and a compound represented by the general formula (I) in JP-A-11-109547. Specifically, compounds of M-1 to M-24 in JP-A-5-341432 and d-1) to d-1 in JP-A-4-18239A are disclosed.
Compound 4), SS described in JP-A-10-111543
-01 to SS-07, JP-A-11-10954
No. 7, 31, 32, 37, 38, 41-45, 51
~ 53 compounds. The addition amount of these supersensitizers is preferably in the range of 10 ^{-4 to} 1 mol per mol of silver halide in the image forming layer (emulsion layer), and in the range of 0.001 to 0.3 mol per mol of silver halide. Is more preferred.

The photothermographic material of the present invention contains a reducing agent for an organic silver salt. The reducing agent for the organic silver salt is any substance that reduces silver ions to metallic silver, preferably an organic substance. Conventional photographic developers such as phenidone, hydroquinone and catechol are useful, but hindered phenol reducing agents are preferred. The reducing agent is preferably contained in an amount of 5 to 50 mol%, more preferably 10 to 40 mol%, per 1 mol of silver on the surface having the image forming layer. The layer to which the reducing agent is added may be any layer on the image forming layer side with respect to the support. When added to a layer other than the image forming layer, 10 to 50 mol% based on 1 mol of silver
It is preferable to use a relatively large amount. Further, the reducing agent may be a so-called precursor which is derivatized so as to function effectively only during development.

In a photothermographic material utilizing an organic silver salt, a wide range of reducing agents can be used. For example,
JP-A-46-6074, JP-A-47-1238, JP-A-47-33621, JP-A-49-46427, JP-A-49-115540, and JP-A-50-1433.
No. 4, No. 50-36110, No. 50-147
Nos. 711 and 51-32632 and 51-1
JP-A Nos. 023721, 51-32324, and 5
JP-A-51-933, JP-A-52-84727, JP-A-55-108654, JP-A-56-146133, JP-A-57-82828, JP-A-57-82829, JP-A-6-3793, U.S.A. Patent No. 3,67
9,426, 3,751,252, 3,751,255, 3,763
Nos. 1,270, 3,782,949, 3,839,048, 3,92
Use of reducing agents disclosed in 8,686, 5,464,738, German Patent 2,321,328, European Patent Publication EP 692,732A and the like. Can be. Amide oximes such as, for example, phenylamide oxime, 2-thienylamide oxime and p-phenoxyphenylamide oxime;
Azines such as, for example, 4-hydroxy-3,5-dimethoxybenzaldehyde azine; aliphatic carboxylic acid arylhydrazides such as a combination of 2,2′-bis (hydroxymethyl) propionyl-β-phenylhydrazine and ascorbic acid and ascorbic acid A combination of polyhydroxybenzene and hydroxylamine, reductone and / or hydrazine (for example, a combination of hydroquinone and bis (ethoxyethyl) hydroxylamine, piperidinohexose reductone or formyl-4-methylphenylhydrazine, etc. ); Hydroxamic acids such as phenylhydroxamic acid, p-hydroxyphenylhydroxamic acid and β-alinine hydroxamic acid; combinations of azines with sulfonamidophenols (eg, phenothiazine 2,6-dichloro-4-benzenesulfonamidophenol); α-cyanophenylacetic acid derivatives such as ethyl-α-cyano-2-methylphenylacetate and ethyl-α-cyanophenylacetate; 2,2′-dihydroxy- 1,1′-binaphthyl, 6,6′-dibromo-2,2′-dihydroxy-
1,1′-Binaphthyl and bis (2-hydroxy-1
Bis-β-naphthol as exemplified by -naphthyl) methane; of bis-β-naphthol and 1,3-dihydroxybenzene derivatives (such as 2,4-dihydroxybenzophenone or 2 ′, 4′-dihydroxyacetophenone). 5-pyrazolone such as 3-methyl-1-phenyl-5-pyrazolone; dimethylaminohexose reductone, anhydrodihydroaminohexose reductone and anhydrodihydropiperidone hexose reductone, as exemplified in the combination; Reducton; 2,6
-Sulfonamide phenol reducing agents such as dichloro-4-benzenesulfonamidophenol and p-benzenesulfonamidophenol; 2-phenylindane-
1,2-dione and the like; 2,2-dimethyl-7-tert
Chromans such as -butyl-6-hydroxychroman;
2,6-dimethoxy-3,5-dicarbethoxy-1,
1,4-dihydropyridines such as 4-dihydropyridine; bisphenols (for example, bis (2-hydroxy-
3-tert-butyl-5-methylphenyl) methane,
2,2-bis (4-hydroxy-3-methylphenyl)
Propane, 4,4-ethylidene-bis (2-tert-
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; 3-pyrazolidone and certain indane-1,3
Diones; chromanols (such as tocopherol); Particularly preferred reducing agents are bisphenol, chromanol.

In the present invention, the reducing agent may be added by any method such as an aqueous solution, an organic solvent solution, a powder, a solid fine particle dispersion and an emulsified dispersion. The dispersion of the solid fine particles is carried out by a known means for making fine (for example, a ball mill, a vibration ball mill, a sand mill, a colloid mill, a jet mill, a roller mill, etc.). When dispersing the solid fine particles, a dispersing aid may be used.

When an additive known as a "toning agent" for improving an image is included, the optical density may increase.
The toning agent may also be advantageous in forming a black silver image. The color tone agent is preferably contained in the layer on the image forming layer side of the support in an amount of 0.1 to 50% mol per 1 mol of silver, more preferably 0.5 to 20% mol. Further, the toning agent may be a so-called precursor which is derivatized so as to function effectively only during development. In a photothermographic material using an organic silver salt, a wide range of color toning agents can be used. For example, JP-A-46-6077 and JP-A-47-10282
No. 49-5019, No. 49-5020, No. 49-91215, No. 50-2524, No. 50-32927, No. 50-67132
Gazettes, JP-A-50-67641, and JP-A-50-1142
No. 17, No. 51-3223, No. 51-279
Nos. 23, 52-14788, 52-99
Nos. 813, 53-1020 and 53-76
Nos. 020, 54-156524 and 54-
Nos. 156525, 61-183642, JP-A-4-56848, JP-B-49-10727, JP-A-54-20333, and U.S. Pat.
0,254, 3,446,648, 3,782,941, 4,12
No. 3,282,4,510,236, British Patent No. 1,380,795, Belgian Patent No. 841,910, etc. may be used. it can. Specific examples of the toning agent include phthalimide and N-hydroxyphthalimide; succinimide, pyrazolin-5-one, and quinazolinone, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline, and 2,4- Cyclic imides such as thiazolidinedione; naphthalimide (eg, N-hydroxy-1,8-naphthalimide); cobalt complex (eg, cobalt hexamine trifluoroacetate); 3-mercapto-1,2,4-triazole; N- (aminomethyl), exemplified by 2,4-dimercaptopyrimidine, 3-mercapto-4,5-diphenyl-1,2,4-triazole and 2,5-dimercapto-1,3,4-thiadiazole Aryldicarboximides (for example, (N, - dimethylaminomethyl) phthalimide and N, N- (dimethylaminomethyl) - naphthalene-2,3-dicarboximide); and blocked pyrazole, 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-benzothiazolinylidene) -1-methylethylidene] -2-thio-2,4-oxazolidinedione; phthalazinone, a phthalazinone derivative or metal salt, or 4- (1-naphthyl) phthalazinone, 6-chlorophthalazinone , 5,7-dimethoxyphthalazinone and 2,
Derivatives such as 3-dihydro-1,4-phthalazinedione; combinations of phthalazinone and phthalic acid derivatives (eg, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride); phthalazine, phthalazine Derivatives (eg, 4- (1-naphthyl) phthalazine, 6-chlorophthalazine, 5,7-dimethoxyphthalazine, 6-isobutylphthalazine, 6-t
derivatives such as tert-butylphthalazine, 5,7-dimethylphthalazine, and 2,3-dihydrophthalazine)
Or a metal salt; phthalazine and its derivatives and phthalic acid derivatives (for example, phthalic acid, 4-methylphthalic acid,
Quinazolinedione, benzoxazine or naphthoxazine derivatives; not only as a color tone regulator but also as a source of halide ions for silver halide formation in situ Rhodium complexes such as ammonium hexachlororhodate (III), rhodium bromide,
Rhodium nitrate and potassium hexachlororhodate (III) and the like; inorganic peroxides and persulfates, for example, ammonium disulfide and hydrogen peroxide; 1,3-benzoxazine-2,4-dione, 8-methyl- 1,3
Benzoxazine-2,4-dione such as benzoxazine-2,4-dione and 6-nitro-1,3-benzoxazine-2,4-dione; pyrimidine and asymmetric-triazines (e.g. 2,4- Dihydroxypyrimidine, 2-hydroxy-4-aminopyrimidine, etc.),
Azauracil and tetraazapentalene derivatives (for example, 3,6-dimercapto-1,4-diphenyl-1
H, 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.

In the present invention, as a color tone agent, JP-A-2000-
Phthalazine derivatives represented by the general formula (F) described in JP-A-35631 are preferably used. Specifically, A-1 to A-10 described in the publication are preferably used.

The color-toning agent may be added by any method such as a solution, a powder, and a solid fine particle dispersion. The dispersion of the solid fine particles is carried out by a known means for making fine (for example, a ball mill, a vibration ball mill, a sand mill, a colloid mill, a jet mill, a roller mill, etc.). When dispersing the solid fine particles, a dispersing aid may be used.

The pH of the surface of the photothermographic material of the present invention before the heat development processing is preferably 6.0 or less, more preferably 5.5 or less. The lower limit is not particularly limited, but is about 3. The adjustment of the film surface pH is preferably performed using an organic acid such as a phthalic acid derivative, a nonvolatile acid such as sulfuric acid, or a volatile base such as ammonia from the viewpoint of reducing the film surface pH. In particular, ammonia is preferable in achieving a low film surface pH since ammonia is easily volatilized and can be removed before the application step and the heat development. Note that the film surface p
The method for measuring H is described in paragraph No. 0123 of JP-A-2000-284399.

In the photothermographic material of the present invention, the silver halide emulsion and / or the organic silver salt may contain an antifoggant,
Stabilizers and stabilizer precursors can further protect against the formation of additional fog and stabilize against reduced sensitivity during storage in inventory. Suitable antifoggants, stabilizers and stabilizer precursors that can be used alone or in combination are described in US Pat. No. 2,131,03.
No. 8, No. 2,694,716, azaindenes described in U.S. Pat. Nos. 2,886,437 and 2,444,605, U.S. Pat. No. 2,728,663, mercury salts described in U.S. Pat. No. 3,287,135, urazole described in U.S. Pat. No. 3,287,135, U.S. Pat. No. 3,235,652.
Patent No. 62, UK Patent No. 62
Oxime, nitrone, nitroindazole described in US Pat. No. 3,448, polyvalent metal salt described in US Pat. No. 2,839,405, US Pat. No. 3,220,839.
No. 2,566,263 and U.S. Pat. No. 2,597,9.
15, palladium, platinum and gold salts; U.S. Pat. Nos. 4,108,665 and 4,4;
No. 4,128,557 and U.S. Pat. Nos. 4,137,079 and 4,138,365.
And the phosphorus compounds described in U.S. Pat. No. 4,411,985.

The photothermographic material of the present invention may contain benzoic acids for the purpose of increasing the sensitivity and preventing fog. The benzoic acid used in the present invention may be any benzoic acid derivative, but a preferred example is described in US Pat.
No. 939, No. 4,152,160, JP-A-9-329863, JP-A-9-329864, and JP-A-9-281637. The benzoic acid may be added to any layer of the photothermographic material, but is preferably added to the layer on the image forming layer side with respect to the support, more preferably to the organic silver salt-containing layer. The addition of benzoic acids may be performed at any step in the preparation of the coating solution, and when the benzoic acid is added to the organic silver salt-containing layer, any step from the preparation of the organic silver salt to the preparation of the coating solution may be performed, but the coating is performed after the preparation of the organic silver salt. Immediately before is preferred.
The benzoic acid may be added by any method such as powder, solution, and fine particle dispersion. Further, it may be added as a solution mixed with other additives such as a sensitizing dye, a reducing agent, and a color tone agent. The benzoic acid may be added in any amount, but may be 1 × 10 ⁻⁶ mol to 2 mol per mol of silver.
1 is preferable, and 1 × 10 ⁻³ mol to 0.5 mol is more preferable.

Although not essential for practicing the present invention,
It may be advantageous to add a mercury (II) salt as an antifoggant to the image forming layer. Preferred mercury (II) salts for this purpose are mercury acetate and mercury bromide. The amount of mercury used in the present invention is 1 mol of silver applied.
1 × 10 ⁻⁹ mol to 1 × 10 ⁻³ mol per liter
l, more preferably 1 × 10 ⁻⁸ mol to 1 × 10 ⁻⁴ m
ol range.

The antifoggant particularly preferably used in the present invention is an organic halide.
No. 119624, No. 50-120328, No. 51-121332, No. 54-58022, No. 56-70543, No. 56-99335, No. 59-90842, No. 61-12964.
No. 2, JP-A-62-129845, JP-A-6-2
JP 08191, JP 7-5621, JP 7-27
No. 81, 8-15809, U.S. Pat.
Compounds disclosed in 340,712, 5,369,000, and 5,464,737 are exemplified. JP-A-2000-2843
The hydrophilic organic halide represented by the formula (P) described in JP-A-99-99 is preferably used as an antifoggant. Specifically, (P-1) to (P-11) described in the same specification
8) is preferably used. The amount of the organic halide to be added is a mol amount (mol / molA) relative to 1 mol of Ag.
g), preferably 1 × 10 ^{−5 to 2} mol / mo
lAg, more preferably 5 × 10 ^{-5 to} 1 mol / mol
Ag, more preferably 1 × 10 ^{-4 to} 5 × 10 ^-1 mol
/ MolAg. These may be used alone or in combination of two or more.

A salicylic acid derivative represented by the formula (Z) described in JP-A-2000-284399 is preferably used as an antifoggant. Specifically, (A-1) to (A-60) described in the same specification are preferably used. The amount of the salicylic acid derivative represented by the formula (Z) may be a molar amount (mol / molA) relative to 1 mol of Ag.
g), preferably 1 × 10 ^{-5 to} 5 × 10 ^-1 mo
1 / mol Ag, more preferably 5 × 10 ⁻⁵ to 1 × 10
⁻¹ mol / mol Ag, more preferably 1 × 10 ⁻⁴ to
It is 5 × 10 ^-2 mol / mol Ag. These may be used alone or in combination of two or more.

As the antifoggant preferably used in the present invention, formalin scavenger is effective. For example, the compound represented by the formula (S) described in JP-A-2000-221634 and its exemplified compound (S-
1) to (S-24).

The antifoggant used in the present invention may be water or a suitable organic solvent such as alcohols (methanol,
It can be used by dissolving in ethanol, propanol, fluorinated alcohol), ketones (acetone, methyl ethyl ketone), dimethylformamide, dimethylsulfoxide, methylcellosolve and the like. In addition, dibutyl phthalate,
Oils such as tricresyl phosphate, glyceryl triacetate or diethyl phthalate, dissolved using an auxiliary solvent such as ethyl acetate or cyclohexanone,
An emulsified dispersion can be prepared and used mechanically. Alternatively, the powder can be dispersed in water by a ball mill, a colloid mill, a sand grinder mill, a Menton-Gaulin, a microfluidizer or an ultrasonic wave by a method known as a solid dispersion method.

The antifoggant used in the present invention may be added to the layer on the image forming layer side with respect to the support, that is, the image forming layer or any other layer on this layer side. It is preferable to add it to an adjacent layer. The image forming layer is a layer containing a reducible silver salt (organic silver salt), and is preferably an image forming layer further containing a photosensitive silver halide.

The photothermographic material of the present invention contains a mercapto compound, a disulfide compound or a thione compound for the purpose of controlling or suppressing the development by improving or improving the preservability before and after the development. Can be. When a mercapto compound is used in the present invention, any structure may be used, but Ar-SM, Ar
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, benzotellurazole, imidazole, oxazole, pyrazole, triazole, thiadiazole, tetrazole, triazine, pyrimidine, pyridazine , Pyrazine, pyridine, purine, quinoline or quinazolinone. The heteroaromatic ring can be, for example, halogen (eg, Br and Cl), hydroxy, amino, carboxy, alkyl (eg, having one or more carbon atoms, preferably 1-4 carbon atoms), alkoxy ( For example, it may have a substituent selected from the group consisting of one or more carbon atoms, preferably those having 1 to 4 carbon atoms, and aryl (which may have a substituent). Good. Examples of the mercapto-substituted heteroaromatic compound include 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-mercapto-5-methylbenzimidazole,
6-ethoxy-2-mercaptobenzothiazole, 2,
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-hydrokilocy-2-mercaptopyrimidine, 2-mercaptopyrimidine, 4,6-diamino-2-mercaptopyrimidine, 2-mercapto-4-
Methyl pyrimidine hydrochloride, 3-mercapto-5
-Phenyl-1,2,4-triazole, 1-phenyl-5-mercaptotetrazole, sodium 3- (5-mercaptotetrazole) -benzenesulfonate, N-
Methyl-N '-{3- (5-mercaptotetrazolyl)
Examples include phenyl diurea and 2-mercapto-4-phenyloxazole, but the present invention is not limited thereto. The amount of the mercapto compound added is 0.0001 to 1.0 m per mol of silver in the image forming layer.
ol is preferable, and more preferably 1 mol of silver.
The amount is 0.001 to 0.3 mol per 1.

The photothermographic material of the present invention is provided on a support.
It is preferable to have an image forming layer containing an organic silver salt, a reducing agent and a photosensitive silver halide, and to provide at least one protective layer on the image forming layer. Further, the photothermographic material of the present invention preferably has at least one back layer on the side (back surface) opposite to the image forming layer with respect to the support, and the image forming layer, the protective layer, and the binder of the back layer As the polymer latex. By using a polymer latex for these layers, aqueous coating using a solvent (dispersion medium) containing water as a main component becomes possible, which is advantageous in terms of environment and cost, and causes wrinkles during thermal development. A heat-developable photosensitive material can be obtained. Further, by using a support which has been subjected to a predetermined heat treatment, a photothermographic material having a small dimensional change before and after thermal development can be obtained.

In the present invention, it is preferable to use a binder which provides good photographic performance and enables aqueous coating. As the main binder on the image forming layer side, specifically, it is preferable to use polymer latex or gelatin, and it is particularly preferable to use the polymer latex described below. Further, at least one of the image forming layers containing the photosensitive silver halide is preferably an image forming layer containing the polymer latex described below in an amount of 50% by mass or more, more preferably 70% by mass or more of the total binder. . Further, the polymer latex may be used not only for the image forming layer but also for the protective layer and the backing layer. It is preferable to use a polymer latex also for the layer. By using a polymer latex for these layers, aqueous coating using a solvent (dispersion medium) containing water as a main component becomes possible, which is advantageous in terms of environment and cost, and causes wrinkles during thermal development. No photothermographic material is obtained. Also,
By using a support which has been subjected to a predetermined heat treatment, a photothermographic material having small dimensional changes before and after thermal development can be obtained.

The “polymer latex” referred to in the present specification is one in which a water-insoluble hydrophobic polymer is dispersed as fine particles in a water-soluble dispersion medium. The dispersion state is such that the polymer is emulsified in a dispersion medium, emulsion-polymerized, micelle-dispersed, or partially dispersed in polymer molecules and the molecular chains themselves are molecularly dispersed. Any of them may be used. The polymer latex used in the present invention is described in "Synthetic Resin Emulsion (Taira Okuda, edited by Hiroshi Inagaki, published by Kobunshi Kankokai (197
8))), "Applications of Synthetic Latex (Edited by Takaaki Sugimura, Yasuo Kataoka, Soichi Suzuki, Keiji Kasahara, Polymer Publishing Association (19)
93)) "," Synthesis of Synthetic Latex (Souichi Muroi, published by Kobunshi Kankokai (1970)) "and the like. The average particle size of the dispersed particles is preferably from 1 to 50,000 nm, more preferably from 5 to 1000 nm. There is no particular limitation on the particle size distribution of the dispersed particles, and they may have a broad particle size distribution or a monodispersed particle size distribution.

The polymer latex used in the present invention may be an ordinary polymer latex having a uniform structure,
It may be a so-called core / shell type latex.
In the case of the core / shell type, it is sometimes preferable that the core and the shell have different glass transition temperatures. In particular, a core / shell type latex in which the Tg of the core is higher than the Tg of the shell provides good film-forming properties.

The glass transition temperature (Tg) of the polymer latex preferably used for the binder used in the present invention differs between the protective layer, the back layer and the image forming layer. In the image forming layer, the temperature is preferably from -30 to 40 ° C. in order to promote diffusion of the photographically useful material during thermal development.
When used for the protective layer or the back layer, the temperature is preferably 25 to 100 ° C. in order to come into contact with various devices. The Tg of the polymer is described, for example, in "J. Brandrup, EHImmergut,"
ymer Handbook, 2nd Edition, III-139 to III-192 (197
5) ".

The minimum film forming temperature (MFT) of the polymer latex used in the present invention is preferably from -30 ° C to 90 ° C, more preferably from about 0 ° C to 70 ° C.
A film-forming aid may be added to control the minimum film-forming temperature. The film forming aid is an organic compound (usually an organic solvent) which is also called a plasticizer and lowers the minimum film forming temperature of the polymer latex. )"It is described in.

The polymer used for the polymer latex of the image forming layer, protective layer and back layer of the present invention includes acrylic resin, vinyl acetate resin, polyester resin, and the like.
Examples thereof include a polyurethane resin, a rubber-based resin, a vinyl chloride resin, a vinylidene chloride resin, a polyolefin resin, and a copolymer thereof. The polymer may be a linear polymer, a branched polymer, or a crosslinked polymer. The polymer may be a so-called homopolymer in which a single monomer is polymerized, or a copolymer in which two or more monomers are polymerized. In the case of a copolymer, it may be a random copolymer or a block copolymer. The molecular weight of the polymer is 5,000 in number average molecular weight.
0 to 1,000,000, preferably 10,000 to 1
About 00,000 is preferable. If the molecular weight is too small, the mechanical strength of the image forming layer is insufficient, and if it is too large, the film-forming property is poor, which is not preferable.

Specific examples of the polymer latex used as a binder for the image forming layer of the photothermographic material of the present invention include a latex of methyl methacrylate / ethyl acrylate / methacrylic acid copolymer, a latex of methyl methacrylate / butadiene / itaconic acid copolymer, Latex of ethyl acrylate / methacrylic acid copolymer, latex of methyl methacrylate / 2-ethylhexyl acrylate / styrene / acrylic acid copolymer, latex of styrene / butadiene / acrylic acid copolymer, latex of styrene / butadiene / divinylbenzene / methacrylic acid copolymer, methyl Latex of methacrylate / vinyl chloride / acrylic acid copolymer, vinylidene chloride / ethyl acrylate / acrylonitrile / Such as latex of methacrylic acid copolymers. More specifically, methyl methacrylate / ethyl acrylate / methacrylic acid = 33.5.
/50/16.5 (% by mass) copolymer latex,
Methyl methacrylate / butadiene / itaconic acid = 4
Examples thereof include a copolymer latex of 7.5 / 47.5 / 5 (% by mass) and a copolymer latex of ethyl acrylate / methacrylic acid = 95/5 (% by mass). Such polymers are also commercially available, for example, Sebian A-4635,465 as an example of an acrylic resin.
83, 4601 (all manufactured by Daicel Chemical Industries, Ltd.), N
ipol LX811, 814, 821, 820, 85
7 (all made by Nippon Zeon Co., Ltd.), VONCORT-R3
As polyester resins such as 340, R3360, R3370, 4280 (all manufactured by Dainippon Ink and Chemicals, Inc.), FINETEX ES650, 611, 675, 8
50 (all manufactured by Dainippon Ink and Chemicals, Inc.), WD-siz
e, polyurethane resins such as WMS (all manufactured by Eastman Chemical) include HYDRAN AP10, 20,
Rubber-based resins such as 30, 40 (all manufactured by Dainippon Ink and Chemicals, Inc.) include LACSTAR 7310K, 330
7B, 4700H, 7132C (all manufactured by Dainippon Ink and Chemicals, Inc.), Nipol LX410, 430, 43
5, 438C (manufactured by Nippon Zeon Co., Ltd.), vinyl chloride resins such as G351 and G576 (manufactured by Nippon Zeon Co., Ltd.), and vinylidene chloride resin, L50
2, L513 (all manufactured by Asahi Kasei Corporation), Aron D7
020, D504, D5071 (Mitsui Toatsu Co., Ltd.
Chemical Pearl S12 as an olefin resin
0, SA100 (all manufactured by Mitsui Petrochemical Co., Ltd.) and the like. These polymers may be used alone or as a blend of two or more as necessary.

A hydrophilic polymer such as gelatin, polyvinyl alcohol, methylcellulose, hydroxypropylcellulose, carboxymethylcellulose, or hydroxypropylmethylcellulose may be added to the image forming layer if necessary in an amount of 50% by mass or less of the whole binder. . The addition amount of these hydrophilic polymers is preferably 30% by mass or less of the total binder in the image forming layer.
More preferably, the content is 5% by mass or less.

The image forming layer is preferably prepared by applying an aqueous coating solution and then drying. However, the term "aqueous" as used herein means that 60% by mass or more of the solvent (dispersion medium) of the coating liquid is water. As components other than water of the coating solution, water-miscible organic solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, methyl cellosolve, ethyl cellosolve, dimethylformamide, and ethyl acetate can be used. Specific examples of the solvent composition include the following. Water / methanol = 90/10, water / methanol = 70/30, water / ethanol = 90/1
0, water / isopropanol = 90/10, water / dimethylformamide = 95/5, water / methanol / dimethylformamide = 80/15/5, water / methanol / dimethylformamide = 90/5/5 (however, figures are mass% Represents.)

Further, as a binder for the protective layer, JP-A-2000-267226, paragraphs [0025] to [0025]
A combination of polymer latexes having different I / O values obtained by dividing an inorganic value by an organic value based on the organic conceptual diagram described in 0029 can be preferably used.

In the present invention, if necessary,
Nos. 00-267226, Paragraph Nos. 0021-002
5 plasticizer (for example, benzyl alcohol, 2,
2,4-trimethylpentanediol-1,3-monoisobutyrate) can be added to control the film formation temperature. Further, Japanese Patent Application Laid-Open No. 2000-26722
As described in Paragraph Nos. 0027 to 0028 of JP-A-6, a hydrophilic polymer may be added to a polymer binder, and a water-miscible organic solvent may be added to a coating solution.

Each layer is described in JP-A-2000-196.
Use of a first polymer latex having a functional group introduced therein and a crosslinking agent having a functional group capable of reacting with the first polymer latex and / or a second polymer latex described in paragraph Nos. You can also. The functional group is a carboxyl group, a hydroxyl group, an isocyanate group, an epoxy group, an N-methylol group, an oxazolinyl group, and the like.As a crosslinking agent, an epoxy compound, an isocyanate compound, a blocked isocyanate compound, a methylol compound, a hydroxy compound, It is selected from a carboxyl compound, an amino compound, an ethyleneimine compound, an aldehyde compound, a halogen compound and the like. Specific examples of the cross-linking agent include hexamethylene isocyanate and duranate WB4 as isocyanate compounds.
0-80D, WX-1741 (manufactured by Asahi Kasei Corporation),
Bayhijur 3100 (Sumitomo Bayer Urethane Co., Ltd.)
Manufactured), Takenate WD725 (Takeda Pharmaceutical Co., Ltd.)
Aquanate 100, 200 (manufactured by Nippon Polyurethane Co., Ltd.), water-dispersible polyisocyanate described in JP-A-9-160172; Sumitex Resin M-3 as an amino compound (manufactured by Sumitomo Chemical Co., Ltd.) An epoxy compound such as Denacol EX-614B (manufactured by Nagase Kasei Kogyo Co., Ltd.); and a halogen compound such as sodium 2,4-dichloro-6-hydroxy-1,3,5-triazine.

The total amount of the binder for the image forming layer is from 0.2 to
Preferably ^{30g / m 2, 1.0~15g / m} 2 is more preferable. A crosslinking agent for crosslinking, a surfactant for improving coating properties, and the like may be added to the image forming layer. The total amount of the binder for the protective layer is preferably an amount that allows the thickness of the protective layer to be 3 μm or more, and specifically 1 to
Preferably ^{10.0g / m 2, 2~6.0g / m} 2 is more preferable. In the present invention, the thickness of the protective layer is preferably 3 μm or more, more preferably 4 μm or more. The upper limit of the thickness of the protective layer is not particularly limited, but is preferably 10 μm or less, more preferably 8 μm or less in consideration of coating and drying. Total amount of binder for the back layer is preferably ^{0.01~10.0g / m 2, 0.05~5.0g / m} 2 is more preferable.

In the present invention, each of these layers may be provided in two or more layers. When there are two or more image forming layers, it is preferable to use a polymer latex as a binder for all the layers. Further, the protective layer is a layer provided on the image forming layer and may be present in two or more layers.
Preferably, a polymer latex is used for at least one layer, particularly the outermost protective layer. The back layer is a layer provided on the undercoat layer on the back surface of the support.
Although there may be more than one layer, it is preferable to use a polymer latex for at least one layer, particularly the outermost back layer.

In the present invention, a slip agent can be used.
As used herein, the term "slip agent" refers to a compound capable of reducing the coefficient of friction of the surface of an object when present on the surface of the object as compared to the case where the agent is not present. The type is not particularly limited.

The slip agent used in the present invention is disclosed in
Paragraph Nos. 0061 to 0064 of 1-84573,
Paragraph No. 0049 of JP-A-2001-83679
Compounds described in 0062 can be mentioned. Specific examples of preferred slip agents include Cellolsol 524 (main component carnauba wax), Polylon A, 393, H-481.
(Main component polyethylene wax), high micron G-1
10 (main component ethylene bisstearic acid amide), Himicron G-270 (main component stearic acid amide)
(Above, Chukyo Yushi Co.), etc. _{W-1 C 16 H 33 -O} -SO 3 Na W-2 C 18 H 37 -O-SO 3 Na and the like. The amount of the slip agent used is 0.1 to 50% by mass of the binder amount of the additive layer, preferably 0.5 to 50% by mass.
30% by mass.

When the photothermographic material of the present invention is thermally developed, JP-A Nos. 2000-171935 and 2001
As described in JP-A-83679, the preheating section is conveyed by an opposing roller, and the heat development processing section is conveyed by driving the roller having the image forming layer on the side having the image forming layer and sliding the back surface on the opposite side to a smooth surface. When a thermal developing machine is used, the ratio of the coefficient of friction at the thermal development processing temperature between the outermost layer on the side having the image forming layer of the photothermographic material and the outermost layer on the back surface may be 1.5 or more. preferable. The upper limit of the friction coefficient ratio is not particularly limited, but is preferably about 30. The friction coefficient ratio can be determined by the following equation. Ratio of friction coefficient = dynamic friction coefficient (μe) between the roller member of the heat developing machine and the surface having the image forming layer / dynamic friction coefficient (μb) between the smooth surface member and the back surface of the heat developing machine μb is 1.0 or less. Preferably, 0.05 to
More preferably, it is 0.8. In the present invention, the slipperiness of the outermost surface layer on the surface having the heat development processor member and the image forming layer at the heat development processing temperature and / or the opposite surface is determined by allowing the outermost surface layer to contain a slipping agent, It can be adjusted by changing.

On both sides of the support, JP-A-64-2054
4, JP-A-1-180537, JP-A-1-18037
No. 209443, JP-A-1-285939,
JP-A-1-296243, JP-A-2-24649
JP, JP-A-2-24648, JP-A-2-18-18
4844, JP-A-3-109545, JP-A-3-137637, JP-A-3-141346, JP-A-3-141347, JP-A-4-96
No. 055, U.S. Pat. No. 4,645,731, JP-A-4-68344, and Japanese Patent No. 2,557,
No. 641, page 2, right column, line 20 to page 3, right column, line 30;
Paragraph No. 0020 of JP-A-2000-39684
[0037] It is preferable to provide an undercoat layer containing a vinylidene chloride copolymer containing 70% by mass or more of a vinylidene chloride monomer repeating unit described in paragraphs [0063] to [0080] of JP-A-2001-83679.

When the amount of the vinylidene chloride monomer is less than 70% by mass, sufficient moisture-proof properties cannot be obtained, and the dimensional change over time after thermal development tends to increase. Further, the vinylidene chloride copolymer preferably contains a repeating unit of a carboxyl group-containing vinyl monomer as another constituent repeating unit of the vinylidene chloride monomer. When such a repeating unit is contained, the polymer (polymer) is crystallized only with the vinyl chloride monomer, and it becomes difficult to form a uniform film when the moisture-proof layer is applied, and the polymer ( This is because a carboxyl group-containing vinyl monomer is indispensable for the stabilization of the polymer). The weight average molecular weight of the vinylidene chloride copolymer used in the present invention is 45.0.
00, preferably 10,000 to 45,
000 is more preferable. When the molecular weight is increased, the adhesiveness between the vinylidene chloride copolymer layer and a support layer such as polyester tends to deteriorate.

The content of the vinylidene chloride copolymer used in the present invention is preferably 0.3 μm or more, more preferably 0.3 μm to 4 μm, as the total thickness per one side of the undercoat layer containing the vinylidene chloride copolymer. Is more preferable.

The vinylidene chloride copolymer layer as the undercoat layer is preferably provided as the first undercoat layer directly provided on the support. Usually, one layer is provided on each side. May be provided in two or more layers.
When a multilayer structure having two or more layers is used, the total amount of the vinylidene chloride copolymer is more preferably within the above range.
These layers may contain a crosslinking agent, a matting agent, and the like in addition to the vinylidene chloride copolymer.

The support may be coated with an undercoat layer using SBR, polyester, gelatin or the like as a binder, if necessary, in addition to the vinylidene chloride copolymer layer. These undercoat layers may have a multilayer structure or may be provided on one side or both sides of the support. The thickness (per layer) of the undercoat layer is generally from 0.01 to 5 μm, and more preferably from 0.05 to 1 μm.

Various supports can be used for the photothermographic material of the present invention. Typical supports include polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate, cellulose nitrate, cellulose ester, polyvinyl acetal, syndiotactic polystyrene, polycarbonate, and paper supports coated on both sides with polyethylene. Can be Among them, biaxially stretched polyester, particularly polyethylene terephthalate, is preferred in terms of strength, dimensional stability, chemical resistance and the like. The thickness of the support is preferably 90 to 180 μm as a base thickness excluding the undercoat layer.

As the support used in the photothermographic material of the present invention, JP-A-10-48772 and JP-A-10-87772
10676, JP-A-10-10677, JP-A-11-65025, JP-A-11-13864
No. 8, polyester which has been subjected to a heat treatment in a temperature range of 130 to 185 ° C. in order to alleviate internal strain remaining in the film at the time of biaxial stretching and eliminate heat shrinkage strain generated during thermal development processing. Particularly, polyethylene terephthalate is preferably used.

The support 12 after such heat treatment was used.
The dimensional change rate by heating at 0 ° C. for 30 seconds is −0.03% to + 0.01% in the vertical direction (MD), and 0 in the horizontal direction (TD).
Preferably, it is 0.04%.

The photothermographic material of the present invention has been described in JP-A No. 11-84573, paragraphs 0040 to 0051, for the purpose of reducing dust adhesion, preventing the occurrence of static marks, and preventing transport failure in the automatic transport step. Can be prevented by using the conductive metal oxide and / or the fluorine-based surfactant described in (1). As the conductive metal oxide, US Pat. No. 5,575,957, JP-A-11-22
Needle-like conductive tin oxide doped with antimony described in paragraphs 0012 to 0020 of JP-A-3901 and fibrous tin oxide doped with antimony described in JP-A-4-29134 are preferably used.

The surface resistivity (surface resistivity) of the metal oxide-containing layer is preferably 10 ¹² Ω or less, more preferably 10 ¹¹ Ω or less in an atmosphere at 25 ° C. and a relative humidity of 20%. Thereby, good antistatic properties can be obtained.
The lower limit of the surface resistivity at this time is not particularly limited, but is usually about 10 ⁷ Ω.

The Beck smoothness of at least one of the surface having the image forming layer of the photothermographic material of the invention and the outermost layer surface opposite to the surface, and preferably both, is 5,000 seconds or less, more preferably 10 seconds or less. 2000 seconds. The Beck smoothness in the present invention is based on Japanese Industrial Standard (JIS).
It can be easily obtained according to P8119 “Method for testing smoothness of paper and paperboard with Beck tester” and TAPPI standard method T479. The Beck smoothness of the outermost layer on the surface having the image forming layer of the photothermographic material and the outermost layer on the opposite side are described in paragraph No. 00 of JP-A-11-84573.
As described in Nos. 52 to 0059, it can be controlled by appropriately changing the particle size and the amount of the matting agent contained in the layers on both surfaces.

In the present invention, a water-soluble polymer can be preferably used as a thickener for imparting coatability. The water-soluble polymer used in the present invention may be a natural product or a synthetic polymer, and the type thereof is not particularly limited. Specifically, as natural products, starches (corn starch, starch, etc.), seaweed (agar, sodium alginate, etc.), vegetable sticky substances (eg, gum arabic), animal proteins (eg, glue, casein, gelatin, egg white, etc.) And fermented sticky substances (such as pullulan and dextrin). Also, semi-synthetic polymers such as starch (soluble starch, carboxyl starch, dextran, etc.),
Cellulose (viscose, methylcellulose, ethylcellulose, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, etc.) can also be used. Furthermore, as synthetic polymers, polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone,
Polyethylene glycol, polypropylene glycol,
Maleic acid copolymer, maleic acid, such as polyvinyl ether, polyethylene imine, polystyrene sulfonic acid or its copolymer, polyvinyl sulfinic acid or its copolymer, polyacrylic acid or its copolymer, acrylic acid or its copolymer, etc. Monoester copolymers, acryloylmethylpropanesulfonic acid or copolymers thereof can be exemplified.

Among these, the water-soluble polymers preferably used are sodium alginate, gelatin, dextran, dextrin, methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, polyethylene glycol, polypropylene glycol, Examples include polystyrenesulfonic acid or its copolymer, polyacrylic acid or its copolymer, maleic acid monoester copolymer, acryloylmethylpropanesulfonic acid or its copolymer, and the like. These are particularly preferably used as thickeners.

Among them, particularly preferred thickeners are gelatin, dextran, methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, polystyrenesulfonic acid or a copolymer thereof, polyacrylic acid or a copolymer thereof. And maleic acid monoester copolymer. These compounds are
It is described in detail in "Applications and Markets of New Water-Soluble Polymers" (published by CMC Corporation, edited by Shinji Nagatomo, issued on November 4, 1988).

The amount of the water-soluble polymer used as a thickener is not particularly limited as long as the viscosity increases when added to a coating solution. Generally, the concentration in the solution is preferably 0.01 to 30.
%, More preferably 0.05 to 20% by weight, particularly preferably 0.1 to 10% by weight. The viscosity obtained by these methods is 1 to 20 as an increase from the initial viscosity.
0 mPa · s is preferable, and more preferably 5 to 100 m
Pa · s. The viscosity was measured at 25 ° C using a B-type rotational viscometer.
The values measured in are shown. When adding to a coating solution or the like, it is generally desirable to add the thickener in a solution as dilute as possible. In addition, it is preferable to perform sufficient stirring during the addition.

The surfactant used in the present invention will be described below. Surfactants used in the present invention are classified into dispersants, coating agents, wetting agents, antistatic agents, photographic control agents, and the like according to the purpose of use. By doing so, those goals can be achieved. In the present invention, any of nonionic and ionic (anion, cation, betaine) surfactants can be used. Further, a fluorine-based surfactant is also preferably used.

Preferred nonionic surfactants include:
Polyoxyethylene, polyoxypropylene, polyoxybutylene, polyglycidyl and a surfactant having a nonionic hydrophilic group of sorbitan can be mentioned. Specifically, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether Polyoxyethylene-polyoxypropylene glycol, polyhydric alcohol fatty acid partial ester, polyoxyethylene polyhydric alcohol fatty acid partial ester, polyoxyethylene fatty acid ester, polyglycerin fatty acid ester, fatty acid diethanolamide, and triethanolamine fatty acid partial ester. be able to.

Examples of the anionic surfactant include a carboxylate, a sulfate, a sulfonate and a phosphate ester. Representative examples thereof include a fatty acid salt, an alkylbenzene sulfonate and an alkylnaphthalenesulfonic acid. Salt, alkyl sulfonate, α-olefin sulfonate, dialkyl sulfosuccinate, α-sulfonated fatty acid salt, N-methyl-N-oleyltaurine, petroleum sulfonate, alkyl sulfate, sulfated oil, polyoxy Examples include ethylene alkyl ether sulfate, polyoxyethylene alkyl phenyl ether sulfate, polyoxyethylene styrenated phenyl ether sulfate, alkyl phosphate, polyoxyethylene alkyl ether phosphate, and naphthalene sulfonate formaldehyde condensate. Can be.

As the cationic surfactant, amine salts,
Examples thereof include quaternary ammonium salts and pyridium salts, and more specifically, primary to tertiary fatty amine salts and quaternary ammonium salts.
And quaternary ammonium salts (tetraalkylammonium salts, trialkylbenzylammonium salts, alkylpyridium salts, alkylimidazolium salts, and the like).

Examples of the betaine-based surfactant include carboxybetaine and sulfobetaine.
-Trialkyl-N-carboxymethylammonium betaine, N-trialkyl-N-sulfoalkylammonium betaine and the like.

These surfactants are described in “Applications of Surfactants” (written by Koshobo and Takao Karimei, published on September 1, 1980).
It is described in. The amount of the surfactant used in the present invention is not particularly limited, and may be any amount as long as desired surfactant properties can be obtained. In addition, the coating amount of the fluorine-containing surfactant is preferably 0.01 mg to 250 mg per 1 m ² .

Specific examples of the surfactant are described below, but the surfactant that can be used in the present invention is not limited to these (here, -C ₆ H _4- represents a phenylene group). . _{WA-1: C 16 H 33} (OCH 2 CH 2) 10 OH WA-2: C 9 H 19 -C 6 H 4 - (OCH 2 CH 2) 12 OH WA-3: sodium dodecylbenzene sulfonate WA-4 : Sodium tri (isopropyl) naphthalenesulfonate WA-5: sodium tri (isobutyl) naphthalenesulfonate WA-6: sodium dodecyl sulfate WA-7: α-sulfosuccinic acid di (2-ethylhexyl) ester sodium salt WA-8: C _{8 H 17 -C 6 H 4 -} (CH 2 CH 2 O) 3 (CH 2) 2 SO 3 K WA-10: cetyltrimethylammonium chloride _{WA-11: C 11 H 23} CONHCH 2 CH 2 N (+) ( CH ₃ ) ₂ -CH ₂ COO ^(-) WA-12: C ₈ F ₁₇ SO ₂ N (C ₃ H ₇ ) (CH ₂ CH ₂ O) ₁₆ H WA-13: C ₈ F ₁₇ SO ₂ N (C _{3 H 7) CH 2 COOK WA} -14: C 8 F 17 SO 3 K WA-15: C 8 F 17 SO 2 N (C 3 H 7) (CH 2 CH 2 O) 4 (CH 2) 4 SO 3 Na WA-16: C ₈ F ₁₇ SO ₂ N ( C ₃ H ₇ ) (CH ₂ ) ₃ OCH ₂ CH ₂ N ⁽⁺⁾ (C
H ₃ ) ₃ -CH ₃ · C ₆ H ₄ -SO ₃ ^(-) WA-17: C ₈ F ₁₇ SO ₂ N (C ₃ H ₇ ) CH ₂ CH ₂ CH ₂ N ⁽⁺⁾ (CH ₃ ) ₂ -C
H ₂ COO ^(-)

In a preferred embodiment of the present invention, an intermediate layer may be provided, if necessary, in addition to the image forming layer and the protective layer. For the purpose of improving productivity and the like, it is preferable that these multiple layers are simultaneously coated in an aqueous system. The coating method includes extrusion coating, slide bead coating, curtain coating, and the like.
The slide bead coating method shown in FIG.

In the case of a silver halide photographic light-sensitive material using gelatin as a main binder, it is rapidly cooled in a first drying zone provided downstream of a coating die, and as a result, gelatinization of gelatin occurs and the coating film is cooled. Is solidified. The coating film that has been cooled and solidified and has stopped flowing is led to the subsequent second drying zone, where the solvent in the coating liquid is volatilized and formed into a film in the subsequent drying zone. As a drying method after the second drying zone, an air loop method in which a jet is blown from a U-shaped duct to a roller-supported support, or a support in which the support is wound around a cylindrical duct in a helical shape, and conveyed and dried. A fire method (air floating method) and the like can be mentioned.

When a layer is formed using a coating liquid in which the main component of the binder is a polymer latex, the flow of the coating liquid cannot be stopped by rapid cooling, so that the preliminary drying is insufficient only in the first drying zone. In some cases.
In this case, a drying method such as that used for a silver halide photographic light-sensitive material causes flow unevenness and drying unevenness, and easily causes a serious defect in the coated surface.

The preferred drying method in the present invention is a horizontal drying method at least until the constant-rate drying is completed, regardless of the first drying zone or the second drying zone as described in JP-A-2000-2964. This is a method of drying in a drying zone. The transfer of the support from the time immediately after the coating until the support is guided to the horizontal drying zone may or may not be horizontal, and the rising angle of the coating machine with respect to the horizontal direction may be between 0 and 70 °. In addition, the horizontal drying zone in the present invention only needs to be conveyed within ± 15 ° up and down with respect to the horizontal direction of the coating machine, and does not mean horizontal conveyance.

In the present specification, “constant-rate drying” means a drying process in which the amount of heat flowing in at a constant liquid film temperature is used for evaporating the solvent. Further, in this specification, “rate-decreasing drying” means that the drying rate is reduced by various factors at the end of drying (diffusion of the material in moisture becomes rate-limiting, retreat of the evaporation surface, etc.), and the applied heat is reduced. It means a drying process that is also used to raise the liquid film temperature. The critical moisture content at which the transition from the constant rate process to the rate decreasing process is 200 to 300%. When the constant-rate drying is completed, the drying proceeds sufficiently until the flow stops, and thus a drying method such as a silver halide photographic light-sensitive material can be employed. It is preferable to dry in a horizontal drying zone to a proper drying point.

When forming the image forming layer and / or the protective layer, the liquid film surface temperature during constant-rate drying is the minimum film forming temperature of the polymer latex (MTF; usually 3 to 5 ° C. higher than the glass transition temperature Tg of the polymer). It is preferable to make the above.
Usually, the temperature is often set to 25 ° C. to 40 ° C. due to the limitation of manufacturing equipment. Further, the dry-bulb temperature during the rate-decreasing drying is preferably a temperature lower than the Tg of the support (usually 80 ° C. or lower in the case of PET). "Liquid film surface temperature" in the present specification refers to the solvent liquid film surface temperature of the coating liquid film applied to the support,
"Dry bulb temperature" means the temperature of the drying air in the drying zone.

When drying is performed under conditions where the liquid film surface temperature during constant rate drying is low, drying tends to be insufficient. For this reason, particularly, the film forming property of the protective layer is significantly reduced, and cracks are easily generated on the film surface. In addition, the film strength is weakened, and serious problems such as susceptibility to damage during transport in an exposure machine or a heat developing machine are likely to occur.

On the other hand, when dried under the condition that the liquid film surface temperature becomes high, the protective layer mainly composed of the polymer latex quickly forms a film, while the lower layer such as the image forming layer has fluidity. Since it is not stopped, irregularities are likely to be generated on the surface. Further, when an excessive heat higher than Tg is applied to the support (base), the dimensional stability and the curl resistance of the photosensitive material tend to deteriorate.

The same applies to the sequential coating in which the lower layer is coated and dried and then the upper layer is coated. Particularly, the coating for performing the simultaneous multi-layer coating in which the upper layer is coated before the lower layer is dried and both layers are dried simultaneously. As for the liquid properties, the pH difference between the coating solution for the image forming layer and the coating solution for the protective layer is preferably 2.5 or less, and the smaller the pH difference, the more preferable. Coating solution pH
When the difference is large, micro-aggregation is likely to occur at the interface of the coating solution, and a serious surface failure such as a coating streak tends to occur during long continuous coating.

The viscosity of the coating liquid of the image forming layer is 15 to 25 ° C.
100 mPa · s is preferable, and more preferably 40 to
70 mPa · s. On the other hand, the coating liquid viscosity of the protective layer is 2
The temperature is preferably 5 to 75 mPa · s at 5 ° C., and more preferably 30 to 60 mPa · s. These viscosities are measured by a B-type viscometer.

Winding after drying is preferably performed under the conditions of a temperature of 20 to 30 ° C. and a relative humidity of 45 ± 20%. Good or inside. Further, when the processing form is a roll product, it is also preferable to use a roll form wound on the side opposite to the winding form at the time of processing in order to remove the curl generated in the winding form. The relative humidity of the photothermographic material is preferably controlled in the range of 20 to 55% (measured at 25 ° C.).

In a conventional photographic emulsion coating solution which is a viscous solution containing a silver halide and containing a silver halide, bubbles are dissolved and disappear in the solution simply by sending the solution under pressure. Even when returned, there is almost no bubble deposition. However, in the case of an image forming layer coating solution containing an organic silver salt dispersion and a polymer latex, which are preferably used in the present invention, the defoaming tends to be insufficient only by pressurized liquid feeding, so that a gas-liquid interface does not occur. It is preferable to remove the bubbles by applying ultrasonic vibration while feeding the solution.

In the defoaming of the coating solution in the present invention, the coating solution is degassed under reduced pressure before being applied, and further degassed by 1.5 kg / cm ^2.
A method in which ultrasonic vibration is applied while maintaining the above-mentioned pressurized state and continuously feeding the liquid without generating a gas-liquid interface is preferable. Specifically, the method described in JP-B-55-6405, page 4, line 20 to page 7, line 11 is preferred.
As an apparatus for performing such defoaming, Japanese Patent Application Laid-Open No. 2000-98
The apparatus shown in the embodiment of FIG. 534 and the apparatus shown in FIG. 2 can be preferably used.

The pressure is preferably 1.5 kg / cm ² or more, more preferably 1.8 kg / cm ² or more. There is no particular upper limit, but usually 5 kg / cm ²
It is about. The applied ultrasonic sound pressure is 0.2V or more,
It is preferably 0.5 V to 3.0 V, and generally it is preferable that the sound pressure is high. However, if the sound pressure is too high, the temperature becomes partially high due to caption, which causes fog. The frequency is not particularly limited, but is usually 10 kHz or more,
Preferably, it is 20 kHz to 200 kHz. In addition, decompression degassing refers to deaeration by increasing the bubble diameter in the coating solution, increasing the buoyancy, and deaeration by reducing the pressure inside the tank (usually a liquid preparation tank or a storage tank). Decompression conditions are -200 mmHg or lower pressure conditions,
The pressure condition is preferably -250 mmHg or lower, and the lowest pressure condition is not particularly limited, but is usually about -800 mmHg. The decompression time is preferably 3
The time is 0 minute or more, more preferably 45 minutes or more, and the upper limit is not particularly limited.

In the present invention, the image forming layer, the protective layer of the image forming layer, the undercoat layer and the back layer are described in JP-A-11-84.
No. 573, paragraphs 0204 to 0208, JP-A-20
Paragraph Nos. 0240 to 0241 of 01-83679
A dye can be contained for the purpose of preventing halation as described in (1).

Various dyes and pigments can be used in the image forming layer from the viewpoint of improving color tone and preventing irradiation. Although any dyes and pigments can be used for the image forming layer, for example, compounds described in paragraph No. 0297 of JP-A-11-119374 can be used. As a method for adding these dyes, any method such as a solution, an emulsion, a solid fine particle dispersion, and a state in which the dye is mordanted with a polymer mordant may be used. The amount of these compounds to be used is determined depending on the desired absorption amount, but it is generally preferable to use them in the range of 1 × 10 ⁻⁶ g to 1 g per 1 m ² .

When an antihalation dye is used in the present invention, the dye has a desired absorption in a desired range, has a sufficiently low absorption in the visible region after treatment, and has a desirable absorbance spectrum shape of the back layer. Any compound can be used, if possible. For example, a compound described in paragraph No. 0300 of JP-A-11-119374 can be used. Further, as described in Belgian Patent No. 733,706, a method in which the concentration of a dye is reduced by discoloration by heating, or by discoloration by light irradiation as described in JP-A-54-17833. A method of reducing the concentration and the like can also be used.

When the photothermographic material of the present invention is used as a mask when preparing a printing plate using a PS plate after the heat development, the photothermographic material after the heat development is exposed to a PS plate in a plate making machine under the exposure conditions for the PS plate. Information to set,
Information for setting plate-making conditions such as a transfer condition of a mask original and a PS plate is carried as image information. Therefore, said irradiation dye, halation dye,
The concentration (use amount) of the filter dye is limited to read them. Since this information is read by LED or laser, Dm of the wavelength range of the sensor
In (minimum concentration) needs to be low, and the absorbance needs to be 0.3 or less. For example, a plate making machine S-FNRIII manufactured by Fuji Photo Film Co., Ltd. uses a light source having a wavelength of 670 nm as a detector and a bar code reader for detecting a register mark. The plate making machine APM manufactured by Shimizu Seisakusho Co., Ltd.
A 670 nm light source is used as an L series barcode reader. That is, Dmin around 670 nm
When the (lowest density) is high, the information on the film cannot be detected accurately, and a work error occurs in the plate making machine such as a conveyance failure and an exposure failure. Therefore, in order to read information with a 670 nm light source, Dmin around 670 nm needs to be low, and the absorbance at 660 to 680 nm after thermal development needs to be 0.3 or less. More preferably, it is 0.25 or less. The lower limit is not particularly limited, but is usually about 0.10.

In the present invention, the exposure apparatus used for imagewise exposure may be any apparatus capable of performing exposure with an exposure time of 10 ⁻⁷ seconds or less, but is generally a laser diode (LD) or a light emitting diode. An exposure apparatus using (LED) as a light source is preferably used. In particular, LD is more preferable in terms of high output and high resolution. Any of these light sources may be used as long as it can generate light of an electromagnetic wave spectrum in a target wavelength range. For example, for LD,
Dye lasers, gas lasers, solid-state lasers, semiconductor lasers, and the like can be used.

The photothermographic material of the present invention is exposed by overlapping a light beam from a light source. The overlap means that the sub-scanning pitch width is smaller than the beam diameter. The overlap can be quantitatively expressed by FWHM / sub-scanning pitch width (overlap coefficient), for example, when the beam diameter is represented by a half width of beam intensity (FWHM). In the present invention, the overlap coefficient is preferably 0.2 or more.

The scanning method of the light source of the exposure apparatus used in the present invention is not particularly limited, and a cylinder outer surface scanning method, a cylinder inner surface scanning method, a plane scanning method, or the like can be used. Also,
The channel of the light source may be a single channel or a multi-channel, but a multi-channel having two or more laser heads is preferable in that high output is obtained and writing time is shortened. In particular, in the case of the cylindrical outer surface method, a multi-channel having several to several tens or more laser heads is preferably used.

The photothermographic material of the present invention has a low haze upon exposure and tends to cause interference fringes. As a technique for preventing the generation of the interference fringes, a technique disclosed in Japanese Patent Application Laid-Open No. Hei 5-113548, for example, in which a laser beam is obliquely incident on a photosensitive material, or WO95 / 3175.
A method using a multi-mode laser disclosed in, for example, Japanese Patent Application Laid-Open No. 4 (Kokai) No. 4 is known, and it is preferable to use these techniques.

The heat development step for forming an image on the photothermographic material of the present invention may be performed by any method, but usually, the photothermographic material exposed imagewise is heated to develop. A preferred embodiment of the heat developing machine used is a type in which the photothermographic material is brought into contact with a heat source such as a heat roller or a heat drum.
No. 56499, JP-A-9-292695, JP-A-9-297385 and International Publication WO95 /
No. 30934, a non-contact type heat developing machine disclosed in JP-A-7-13294, International Publication WO97
No./28489, 97/28488 and 97/28487. Particularly preferred is a non-contact type thermal developing machine. A preferred development temperature is 80 to 250 ° C., more preferably 10 to 250 ° C.
0-140 ° C. The development time is preferably from 1 to 180 seconds, more preferably from 5 to 90 seconds. Line speed is 1
It is preferably at least 40 cm / min, more preferably at least 150 cm / min.

As a method for preventing processing unevenness due to a dimensional change of the photothermographic material at the time of thermal development, a temperature of 80.degree.
It is effective to employ a method of heating at 5 ° C. or more so that an image is not formed at a temperature of less than 15 ° C., and then thermally developing at 110 ° C. to 140 ° C. to form an image (a so-called multi-step heating method). .

When the photothermographic material of the present invention is subjected to thermal development processing, it is exposed to a high temperature of 110 ° C. or more, so that a part of the components contained in the material or a part of the components decomposed by the thermal development are removed. Volatilizes. These volatile components cause uneven development, corrode the components of the heat developing machine, precipitate at low temperatures, cause deformation of the screen as foreign matter, adhere to the screen and become dirty. It is known that various adverse effects, such as the occurrence of such a problem, occur. As a method for eliminating these effects, it is known to install a filter in the heat developing machine and optimally adjust the flow of air in the heat developing machine. These methods can be effectively used in combination. For example, International Publication WO95 / 3
No. 0933, 97/21150, Tokuheihei 1
Japanese Patent Publication No. 0-500496 discloses a heating device for heating a filter cartridge having a first opening for introducing volatile components and having a second opening for discharging volatile substances, which is in contact with a film. It is described. In addition, International Publication WO96 / 12213, Japanese Patent Publication No.
JP-A-507403 describes the use of a filter combining a thermally conductive condensation collector and a gas-absorbing particulate filter. In the present invention, these can be preferably used. No. 4,518,8.
No. 45, Japanese Patent Publication No. 3-54331 describes a configuration having a device for removing vapor from a film, a pressure device for pressing the film against a heat transfer member, and a device for heating the heat transfer member. ing. In addition, International Publication WO98 / 27
No. 458 describes removing a component which increases fog volatilized from a film from the film surface. These can also be preferably used in the present invention.

FIG. 2 shows an example of the configuration of a heat developing machine used for the heat development of the photothermographic material of the present invention. FIG. 2 is a side view of the heat developing machine. The heat developing machine of FIG. 2 includes a carry-in roller pair 11 (an upper roller is a silicon rubber roller and a lower roller is an aluminum heat roller) for carrying the heat development photosensitive material 10 into a heating section while correcting and preheating the heat-developable photosensitive material 10 into a flat shape. It has a carry-out roller pair 12 for carrying out the heat-developable photosensitive material 10 from the heating unit while correcting the heat-developable photosensitive material 10 into a planar shape. The photothermographic material 10 has a carry-in roller pair 1
While being transported from 1 to the discharge roller pair 12, it is thermally developed. In the conveying means for conveying the photothermographic material 10 during the heat development, a plurality of rollers 13 are provided on the side where the surface having the image forming layer contacts, and the non-woven fabric (for example, Aromatic polyamide and Teflon
(Composed of (registered trademark)) and the like.
Is installed. The photothermographic material 10 is conveyed while the back surface is slid over the smooth surface 14 by driving a plurality of rollers 13 that come into contact with the surface having the image forming layer. A heater 1 is provided on the upper portion of the roller 13 and the lower portion of the smooth surface 14 so as to be heated from both sides of the photothermographic material 10.
5 is installed. As a heating means in this case, a plate heater or the like can be used. Although the clearance between the roller 13 and the smooth surface 14 varies depending on the member of the smooth surface, it is appropriately adjusted to a clearance that can transport the photothermographic material 10.
Preferably it is 0 to 1 mm.

Material of Roller 13 Surface and Smooth Surface 1
The member of No. 4 is durable at high temperature and may be anything as long as it does not hinder the conveyance of the photothermographic material 10, but the material of the roller surface is made of silicon rubber, and the member of the smooth surface is made of aromatic polyamide or Teflon (PTFE). Non-woven fabrics are preferred. It is preferable to use a plurality of heaters as the heating means and to set the heating temperature freely.

The heating section is composed of a preheating section A having a carry-in roller pair 11 and a heat development heating section B having a heating heater 15, but a preheating section upstream of the heat development processing section B. A is lower than the heat development temperature (for example, 10 to 3).
(Lower by about 0 ° C.), it is desirable to set the temperature and time to be sufficient to evaporate the amount of water in the photothermographic material 10, and to be higher than the glass transition temperature (Tg) of the support of the photothermographic material 10. It is preferable to set the temperature so that uneven development does not occur. The temperature distribution of the preheating section and the heat development section is preferably ± 1 ° C. or less, more preferably ± 0.1 ° C.
5 ° C. or lower is preferred. Further, a guide plate 16 is provided downstream of the thermal development processing section B, and a slow cooling section C having the carry-out roller pair 12 and the guide plate 16 is provided. Guide plate 16
Is preferably a material having a low thermal conductivity.
The cooling is preferably performed gradually so as not to cause deformation, and the cooling rate is preferably 0.5 to 10 ° C./sec.

Although the above has been described with reference to the illustrated example, the invention is not limited to this. For example, the thermal developing machine used in the present invention, such as that described in JP-A-7-13294, may have various structures. In the case of the multi-stage heating method preferably used in the present invention, in the above-described apparatus,
Two or more heat sources having different heating temperatures may be provided, and heating may be performed continuously at different temperatures.

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The present invention will be described more specifically with reference to the following examples. The materials, amounts, proportions,
The processing content, processing procedure, and the like can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples described below.

Example 1 << Preparation of Silver Halide Emulsion A >> Alkali-treated gelatin (2700 ppm in terms of calcium content) was added to 700 ml of water.
Below) 11 g, potassium bromide 30 mg, and sodium 4-methylbenzenesulfonate 1.3 g were dissolved,
The pH was adjusted to 6.5 at 45 ° C. Then, silver nitrate 1
159 ml of an aqueous solution containing 8.6 g and 1 m of potassium bromide
ol / L, (NH ₄ ) ₂ RhCl ₅ (H ₂ O) was 5 × 10 ⁻⁶
mol / L and K ₃ IrCl ₆ at 2 × 10 ⁻⁵ mol / L
Was added over 6 minutes and 30 seconds by the control double jet method while maintaining the pAg at 7.7. Then, 476 ml of an aqueous solution containing 55.5 g of silver nitrate, 1 mol / L of potassium bromide and 2 × 10 ₃ of K ₃ IrCl ₆ were added.
^-5 mol / L of a halogen salt aqueous solution containing pAg of 7.7
28 minutes 3 by the control double jet method while keeping
Added over 0 seconds. Thereafter, the pH is lowered to cause coagulation sedimentation and desalting treatment, and low-molecular-weight gelatin having an average molecular weight of 15,000 (calculated as 20 ppm or less) 5
The pH was adjusted to 5.9 and the pAg to 8.0 by adding 1.1 g.
The obtained particles were cubic particles having an average particle size of 0.11 μm, a projected area variation coefficient of 9%, and a (100) plane ratio of 90%. The temperature of the obtained silver halide grains was raised to 60 ° C., and sodium benzenethiosulfonate was added per mole of silver.
6 μmol was added, and after 3 minutes, triethylthiourea 71 was added.
After the addition of μmol, the mixture was aged for 100 minutes, 5 × 10 ⁻⁴ mol of 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene and 0.17 g of compound A were added, and then 40 ° C. The temperature was lowered. Thereafter, the temperature was maintained at 40 ° C., and 4.7 × 10 ⁻² mol per mol of silver halide.
1 potassium hydroxide (added as an aqueous solution), 12.8 × 1
^0-4 mol of the following sensitizing dye A (added as an ethanol solution) and 6.4 × 10 ^-3 mol of compound B (added as a methanol solution) are added with stirring, and after 20 minutes, 30
The mixture was rapidly cooled to ° C. to complete the preparation of silver halide emulsion A.

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<< Preparation of Silver Behenate Dispersion A >> Behenic acid (Edenor C22-85R, manufactured by Henkel)
6 kg, 423 L of distilled water, 49.2 L of a 5 mol / L aqueous solution of NaOH, and 120 L of tert-butyl alcohol were mixed and reacted by stirring at 75 ° C. for 1 hour to obtain a sodium behenate solution. Separately, silver nitrate 40.4k
g of an aqueous solution (206.2 L) was prepared and kept at 10 ° C. A reaction vessel containing 635 L of distilled water and 30 L of tert-butyl alcohol was kept at 30 ° C., and while stirring, the whole amount of the sodium behenate solution and the whole amount of the silver nitrate aqueous solution were kept at a constant flow rate for 62 minutes 10 seconds and 60 minutes, respectively. Added over minutes. At this time, only the silver nitrate aqueous solution was added for 7 minutes and 20 seconds after the start of the silver nitrate aqueous solution addition, and then the sodium behenate solution was started to be added. After 9 minutes and 30 seconds after the completion of the silver nitrate aqueous solution addition, only the sodium behenate solution was added. It was made to be added. At this time, the temperature in the reaction vessel was set to 30 ° C., and the temperature was controlled so as not to rise. In addition, the piping for the addition system of the sodium behenate solution
The temperature was maintained by steam tracing, and the amount of steam was controlled so that the liquid temperature at the outlet at the tip of the addition nozzle became 75 ° C. The piping of the silver nitrate aqueous solution addition system was kept warm by circulating cold water outside the double pipe. The addition position of the sodium behenate solution and the addition position of the aqueous silver nitrate solution were arranged symmetrically with respect to the stirring axis, and were adjusted to a height such that they did not come into contact with the reaction solution. After the completion of the addition of the sodium behenate solution, the mixture was left to stir at the same temperature for 20 minutes, and the temperature was lowered to 25 ° C. Thereafter, the solid content was separated by centrifugal filtration, and the solid content was washed with water until the conductivity of the filtrate became 30 μS / cm. The solid thus obtained was stored as a wet cake without drying. When the morphology of the obtained silver behenate particles was evaluated by electron microscopy,
Average projected area diameter 0.52 μm, average grain thickness 0.14 μm
m, a scale-like crystal having a coefficient of variation of the average equivalent sphere diameter of 15%.

Next, a dispersion of silver behenate was prepared by the following method. For a wet cake having a dry solid content of 100 g, polyvinyl alcohol (Kuraray Co., Ltd., PVA-
217, average degree of polymerization: about 1700) and water were added to make the total amount 385 g, and then the mixture was predispersed with a homomixer. Next, the pre-dispersed undiluted solution is dispersed in a dispersing machine (Microfluidizer M-110SE-E manufactured by Microfluidics International Corporation).
H, using a G10Z interaction chamber) was adjusted to 1750 kg / cm ² and treated three times to obtain a silver behenate dispersion A. At this time, the desired dispersion temperature was set by adjusting the temperature of the refrigerant by mounting the coiled heat exchangers before and after the interaction chamber, respectively. The silver behenate particles contained in the obtained silver behenate dispersion A had a volume-weighted average diameter of 0.52 μm and a coefficient of variation of 15
% Particles. Particle size measurement is available from MalvernInstr
Performed with MasterSizerX manufactured by uments Ltd. When evaluated by electron microscopy, the ratio of the long side to the short side was 1.
5, the grain thickness was 0.14 μm, and the average aspect ratio (the ratio of the circle equivalent diameter of the projected area of the grain to the grain thickness) was 5.1. The obtained silver behenate dispersion A was used for preparing the following coating liquid.

<< Preparation of Dispersion of Solid Fine Particles of Reducing Agent >> Reducing Agent [1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane] 10k
g and 10 kg of a 20% by mass aqueous solution of a modified polyvinyl alcohol (Kuraray Co., Ltd., Poval MP203), 400 g of Surfynol 104E (Nissin Chemical Co., Ltd.), 640 g of methanol, and 16 kg of water are added and mixed well. To make a slurry. This slurry was fed by a diaphragm pump and filled with zirconia beads having an average diameter of 0.5 mm in a horizontal bead mill (made by Imex Co., Ltd., U.S.A.).
After dispersing for 3 hours and 30 minutes in VM-2), 4 g of benzoisothiazolinone sodium salt and water were added to adjust the concentration of the reducing agent to 25% by mass to obtain a solid fine particle dispersion of the reducing agent. Was. The reducing agent particles contained in the dispersion thus obtained had a median diameter of 0.44 μm, a maximum particle diameter of 2.0 μm or less, and a coefficient of variation of the average particle diameter of 19%. The obtained dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust, and then used for preparing the following coating solution.

<< Preparation of Solid Fine Particle Dispersion of Organic Polyhalogen Compound A >> 10 kg of organic polyhalogen compound A [tribromomethyl (4- (2,4,6-trimethylphenylsulfonyl) phenyl) sulfone] and modified polyvinyl alcohol (Poval MP203, manufactured by Kuraray Co., Ltd.)
10 kg of a 20% by weight aqueous solution of sodium triisopropylnaphthalenesulfonate
g, Surfynol 104E (manufactured by Nissin Chemical Co., Ltd.) 40
0 g, 640 g of methanol and 16 kg of water were added and mixed well to form a slurry. This slurry was fed by a diaphragm pump, and a horizontal bead mill (IMEX) filled with zirconia beads having an average diameter of 0.5 mm was used.
After dispersion for 5 hours with UVM-2), water was added to adjust the concentration of the organic polyhalogen compound A to 25% by mass to obtain a solid fine particle dispersion of the organic polyhalogen compound A. Was. The organic polyhalogen compound particles contained in the dispersion thus obtained have a median diameter of 0.36 μm.
m, the maximum particle diameter was 2.0 μm or less, and the coefficient of variation of the average particle diameter was 18%. The resulting dispersion had a pore size of 3.0μ.
After filtration with a polypropylene filter of m to remove foreign matter such as dust, the mixture was used for preparing the following coating solution.

<< Preparation of Solid Particle Dispersion of Organic Polyhalogen Compound B >> 5 kg of organic polyhalogen compound B [tribromomethylnaphthyl sulfone] and 20 parts of modified polyvinyl alcohol (Poval MP203, manufactured by Kuraray Co., Ltd.)
A 2.5% by mass aqueous solution, 213 g of a 20% by mass aqueous solution of sodium triisopropylnaphthalenesulfonate, and 10 kg of water were added and mixed well to form a slurry. This slurry was sent by a diaphragm pump and dispersed for 5 hours in a horizontal bead mill (UVM-2, manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm. 5 g and water were added to adjust the concentration of the organic polyhalogen compound B to 23.5% by mass to obtain a solid fine particle dispersion of the organic polyhalogen compound B. The organic polyhalogen compound particles contained in the obtained dispersion had a median diameter of 0.38 μm, a maximum particle diameter of 2.0 μm or less, and a coefficient of variation of the average particle diameter of 20%. The resulting dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust, and then used for preparing the following coating solution.

<< Preparation of Aqueous Solution of Organic Polyhalogen Compound C >> 75.0 ml of water and sodium tripropylnaphthalenesulfonate (20% aqueous solution) with stirring at room temperature
8.6 ml, 6.8 ml of sodium dihydrogen orthophosphate dihydrate (5% aqueous solution) and 1 part of potassium hydroxide
9.5 ml of a mol / L aqueous solution was sequentially added, and the mixture was stirred and mixed for 5 minutes after completion of the addition. Further, while stirring, 4.0 g of powder of organic polyhalogen compound C (3-tribromomethanesulfonylbenzoylaminoacetic acid) was added, and the mixture was uniformly dissolved until the solution became transparent to obtain 100 ml of an aqueous solution.
The resulting aqueous solution was filtered through a 200-mesh polyester screen to remove foreign substances such as dust, and then used for preparing the following coating solution.

<< Preparation of Emulsified Dispersion of Compound Z >> Compound Z
10% of R-054 manufactured by Sanko Co., Ltd. containing 85% by mass of
g and 11.66 kg of MIBK were mixed, and then replaced with nitrogen and dissolved at 80 ° C. for 1 hour. To this solution was added 25.52 kg of water and MP polymer manufactured by Kuraray Co., Ltd. (MP-2 manufactured by Kuraray Co., Ltd.).
03) and 0.44 kg of a 20% by weight aqueous solution of sodium triisopropylnaphthalenesulfonate were added at 20 to 40 ° C and 3600%.
The mixture was emulsified and dispersed at 60 rpm for 60 minutes. Further, 0.08 kg of Surfynol 104E (manufactured by Nissin Chemical Co., Ltd.) was added to this solution.
And 47.94 kg of water were added, and MIBK was removed by distillation under reduced pressure, and then prepared so that the concentration of compound Z was 10% by mass. The particles of compound Z contained in the dispersion thus obtained had a median diameter of 0.19 μm, a maximum particle diameter of 1.5 μm or less, and a variation coefficient of the particle diameter of 17%. The obtained dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust, and stored.

<< Preparation of Dispersion of 6-Isopropylphthalazine Compound >> Modified polyvinyl alcohol (Poval MP, manufactured by Kuraray Co., Ltd.) while stirring 62.35 g of water at room temperature
203) 2.0 g was added so as not to form a lump, and stirred and mixed for 10 minutes. Thereafter, the mixture was heated and heated up to an internal temperature of 50 ° C., and then stirred for 90 minutes at an internal temperature of 50 to 60 ° C. to be uniformly dissolved. The internal temperature was lowered to 40 ° C. or lower, and polyvinyl alcohol (manufactured by Kuraray Co., Ltd., PVA-217, 1
25.5 g of a 0 mass% aqueous solution), 3.0 g of sodium tripropylnaphthalene sulfonate (a 20 mass% aqueous solution),
And 6.15 g of 6-isopropylphthalazine (70% by mass aqueous solution) were added, and the mixture was stirred for 30 minutes and the transparent dispersion 10 was added.
0 g was obtained. The obtained dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust, and then used for preparing the following coating solution.

<< Preparation of dispersion of solid fine particles of compound of the present invention >> A modified polyvinyl alcohol (Poval PV, manufactured by Kuraray Co., Ltd.) was added to 4 kg of the compound of the present invention shown in Table 13.
A-217) 1 kg and 36 kg of water were added and mixed well to form a slurry. This slurry was sent by a diaphragm pump, and a horizontal sand mill filled with zirconia beads having an average diameter of 0.5 mm (Umex Corporation, U.S.A.)
VM-2), and after dispersing for the time shown in Table 13, benzoisothiazolinone sodium salt was added as a preservative to 100
ppm. Further, water was added to adjust the concentration of the compound of the present invention to 10% by weight.
A solid fine particle dispersion of the compound having the properties shown in No. 3 was obtained. For comparison, a methanol solution of the compound of the present invention shown in Table 14 was prepared.

[0159]

[Table 13]

[0160]

[Table 14]

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<< Preparation of Solid Fine Particle Dispersion of Development Accelerator W >> Development accelerator W (10 kg), 20% by mass of modified polyvinyl alcohol (Poval MP203, manufactured by Kuraray Co., Ltd.)
An aqueous solution (10 kg) and water (20 kg) were added and mixed well to form a slurry. This slurry was sent by a diaphragm pump and filled with zirconia beads having an average diameter of 0.5 mm in a horizontal bead mill (manufactured by Imex Co., Ltd., UV
After dispersing for 5 hours in M-2), water was added to adjust the concentration of the development accelerator W to 20% by mass to obtain a solid fine particle dispersion of the development accelerator W. The organic polyhalogen compound particles contained in the obtained dispersion have a median diameter of 0.5.
μm, the maximum particle diameter was 2.0 μm or less, and the coefficient of variation of the average particle diameter was 18%. The resulting dispersion had a pore size of 3.0.
After filtration with a μm polypropylene filter to remove foreign substances such as dust, the mixture was used for preparing the following coating solution.

<< Preparation of Coating Solution for Image Forming Layer >> The following binder, material, and silver halide emulsion were added to 1 mol of silver of silver behenate dispersion A prepared above.
Water was added to obtain an image forming layer coating solution. After the preparation, vacuum degassing was performed at a pressure of 0.54 atm for 45 minutes. The coating solution had a pH of 7.7 and a viscosity of 50 mPa · s at 25 ° C.

Binder; SBR latex 397 g as solid content (St / Bu / AA = 68/29/3 (% by weight), using Na ₂ S ₂ O ₈ as a polymerization initiator) 1,1-bis (2-hydroxy (3,5-dimethylphenyl) -3,5,5-trimethylhexane 130.0 g as a solid content Organic polyhalogen compound B 36.3 g as a solid content Organic polyhalogen compound C 2.34 g as a solid content Sodium ethylthiosulfonate 0.47 g Benzotriazole 1.02 g Polyvinyl alcohol (PVA-235 manufactured by Kuraray Co., Ltd.) 10.8 g 6-isopropylphthalazine 15.0 g Compound Z 9.0 g as solid content Compound of the present invention, added as shown in Table 13 7.1 g as solid content Dye A (added as a mixture with low molecular weight gelatin having an average molecular weight of 15,000) Light at 783 nm Concentration coating amount to be 0.3 halide emulsion A Ag amount as 40ppm Compound A coating solution as 0.06mol preservative (solid 0.40g as a guide) (2.5 mg / m ² as coated amount) 1% by mass as the total solvent amount in the coating solution of methanol 2% by mass as the total solvent amount in the coating solution of ethanol (The glass transition temperature of the coating film was 17 ° C.)

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<< Preparation of Coating Solution for Protective Layer >> Methyl methacrylate / styrene / 2-ethylhexyl acrylate / 2
-Hydroxyethyl methacrylate / acrylic acid = 5
8.9 / 8.6 / 25.4 / 5.1 / 2 (% by mass) of a polymer latex solution (glass transition temperature of copolymer: 46
° C (calculated value), a solid content concentration of 21.5% by mass, 100 ppm of compound A, and compound D as a film-forming aid.
Was added to 15% by mass of the solid content of the latex to give a coating solution having a glass transition temperature of 24 ° C .; water was added to 943 g of an average particle diameter of 116 nm, and 114.8 g of an aqueous solution of an organic polyhalogen compound C was added. 17.0 g of the polyhalogen compound A as solid, 0.69 g of sodium dihydrogen orthophosphate dihydrate as solid, 11.55 g of development accelerator W as solid, matting agent (polystyrene particles, average particle Diameter 7μm, coefficient of variation of average particle diameter 8
%), 1.58 g of polyvinyl alcohol (29.3 g of Kuraray Co., Ltd., PVA-235) and 1.62 g of compound E, and further water was added to give a coating solution (containing 0.8% by mass of a methanol solvent). Prepared. After the preparation, vacuum degassing was performed at a pressure of 0.47 atm for 60 minutes. The resulting protective layer coating solution had a pH of 5.5 and a viscosity of 45 mP at 25 ° C.
a · s.

<< Preparation of Coating Solution for Lower Overcoat Layer >> Methyl methacrylate / styrene / 2-ethylhexyl acrylate / 2-hydroxyethyl methacrylate / acrylic acid = 58.9 / 8.6 / 25.4 / 5.1 / 2
(Mass%) polymer latex solution (copolymer glass transition temperature 46 ° C. (calculated value), solid content concentration 21.5 mass%, compound A 100 ppm), and compound D as latex Water was added to 625 g of 15% by mass based on the solid content, and the glass transition temperature of the coating solution was set to 24 ° C .;
0.23 g of compound C, 0.13 g of compound E, 11.7 g of compound F, 2.7 g of compound H and polyvinyl alcohol (PVA-235, manufactured by Kuraray Co., Ltd.)
5 g was added, and water was further added to prepare a coating solution (containing 0.1% by mass of a methanol solvent). After preparation, pressure 0.4
Vacuum deaeration was performed at 7 atm for 60 minutes. The coating solution had a pH of 2.6 and a viscosity of 30 mPa · s at 25 ° C.

<< Preparation of Coating Solution for Upper Overcoat Layer >> Methyl methacrylate / styrene / 2-ethylhexyl acrylate / 2-hydroxyethyl methacrylate / acrylic acid = 58.9 / 8.6 / 25.4 / 5.1 / 2
(Mass%) polymer latex solution (copolymer glass transition temperature 46 ° C. (calculated value), solid content concentration 21.5 mass%, compound A 100 ppm), and compound D as latex Water was added to 649 g of a coating solution having a glass transition temperature of 24 ° C .; an average particle diameter of 116 nm, and carnava wax (manufactured by Chukyo Yushi Co., Ltd., Cellosol 524; 18.4 g of a 30% by mass solution of a silicone content of less than 5 ppm, 0.23 g of compound C, 1.85 g of compound E, 1.0 g of compound G, matting agent (polystyrene particles, average particle diameter of 7 μm, average particle diameter) Coefficient of variation 8%)
3.45 g and polyvinyl alcohol (Kuraray Co., Ltd.)
Co., Ltd., PVA-235) was added, and water was further added to prepare a coating solution (containing 1.1% by mass of a methanol solvent). After preparation, vacuum deaeration was performed at a pressure of 0.47 atm.
Minutes. The coating solution has a pH of 5.3 and a viscosity of 2 at 25 ° C.
It was 5 mPa · s.

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<< Preparation of Polyethylene Terephthalate (PET) Support with Back / Undercoat Layer >> (1) Preparation of PET Support Using terephthalic acid and ethylene glycol, the intrinsic viscosity IV = 0.66 (phenol PET / measured at 25 ° C. in 6/4 (mass ratio)
I got This was pelletized, dried at 130 ° C. for 4 hours, melted at 300 ° C., and extruded from a T-die. Thereafter, the film was rapidly cooled to prepare an unstretched film having a thickness of 120 μm after heat setting. This was longitudinally stretched 3.3 times at 110 ° C. using rolls having different peripheral speeds, and then horizontally stretched 4.5 times at 130 ° C. using a tenter. Then, after heat-setting at 240 ° C. for 20 seconds, it was relaxed by 4% in the lateral direction at the same temperature. Then, after slitting the chuck portion of the tenter, knurling is performed on both ends, and 4.8 kg
/ Cm ² . In this way, the width 2.4 m,
A roll-shaped PET support having a length of 3500 m and a thickness of 120 μm was obtained.

(2) Preparation of Undercoat Layer and Back Layer Undercoat First Layer After subjecting the PET support to a corona discharge treatment at 0.375 kV · A · min / m ² , a coating solution having the following composition was applied to the PET support. .2 ml / m ² on a support,
30 seconds at 150 ° C., then 30 seconds at 150 ° C., then 185 ° C.
For 30 seconds.

Latex-A 280 g KOH 0.5 g Polystyrene fine particles (average particle diameter 2 μm, coefficient of variation of average particle diameter 7%) 0.03 g 2,4-dichloro-6-hydroxy-s-triazine 1.8 g Compound-Bc -C 0.097g Distilled water Amount that total amount becomes 1000g

Second layer of undercoat A coating solution having the composition shown below was applied on the first layer of undercoat so as to have a concentration of 5.5 ml / m ^2, and was applied at 125 ° C. for 30 seconds, then at 150 ° C. for 30 seconds, and further at 170 ° C. Dry at 30 ° C. for 30 seconds.

Deionized gelatin (Ca ²⁺ content: 0.6 ppm, jelly strength: 230 g) 10 g Acetic acid (20% by mass aqueous solution) 10 g Compound-Bc-A 0.04 g Methyl cellulose (2% by mass aqueous solution) 25 g Polyethyleneoxy compound 3g Distilled water Amount that totals 1000g

Back first layer A surface of 0.375 kV ·
A · min / m ² of corona discharge treatment, and a coating solution having the following composition was applied to the surface so as to have a composition of 13.8 ml / m ² at 125 ° C. for 30 seconds, and then at 150 ° C. for 30 seconds. Further, it was dried at 185 ° C. for 30 seconds.

Julimer ET410 (30% by mass aqueous dispersion, manufactured by Nippon Pure Chemical Co., Ltd.) 23 g Alkali-treated gelatin (molecular weight: about 10,000, Ca ²⁺ content: 30 ppm) 4.44 g Deionized gelatin (Ca ²⁺ content: 0.4%) 0.84 g Compound-Bc-A 0.02 g Dye-Bc-A (adjusted to an optical density of 1.33 to 1.4 at 783 nm) As a guide 0.88 g Polyoxyethylene phenyl ether 1.7 g Water-soluble melamine compound (Sumitomo Chemical Co., Ltd., Sumitex Resin M-3, 8% by mass aqueous solution) 15 g Sb-doped SnO ₂ aqueous dispersion of needle-like particles (Ishihara Sangyo Co., Ltd., FS-10D) 24 g polystyrene fine particles (average particle diameter 2 μm, coefficient of variation of average particle diameter 7%) 0.03 g distilled water The total amount becomes 1000 g

Back second layer A coating solution having the composition shown below was applied onto the first back layer so as to have a concentration of 5.5 ml / m ^2.
It was dried at 50 ° C. for 30 seconds and further at 170 ° C. for 30 seconds.

Julimer ET410 (30% by mass aqueous dispersion, manufactured by Nippon Pure Chemical Co., Ltd.) 57.5 g Polyoxyethylene phenyl ether 1.7 g Water-soluble melamine compound (Sumitec Resin M-, manufactured by Sumitomo Chemical Co., Ltd.) 3,8% by mass aqueous solution) 15g Cellosol 524 (30% by mass aqueous solution, manufactured by Chukyo Yushi Co., Ltd.) 6.6g Distilled water Amount that gives a total amount of 1000g

Back third layer The same coating solution as the first undercoat layer was applied onto the second back layer so as to have a concentration of 6.2 ml / m ^2, and was applied at 125 ° C. for 30 seconds, then at 150 ° C. for 30 seconds, and further at 185 ° C. Dry at 30 ° C. for 30 seconds.

Back fourth layer A coating solution having the following composition was applied on the back third layer so as to have a concentration of 13.8 ml / m ^2, and was applied at 125 ° C. for 30 seconds, then at 150 ° C. for 30 seconds, and further at 170 ° C. For 30 seconds.

Latex-B 286 g Compound-Bc-B 2.7 g Compound-Bc-C 0.6 g Compound-Bc-D 0.5 g 2,4 Dichloro-6-hydroxy-s-triazine 2.5 g Polymethyl methacrylate (10 Mass% aqueous dispersion, average particle diameter 5 μm, coefficient of variation of average particles 7%)

[0182]

Embedded image

Latex-A: Core-shell type latex having 90% by mass of core and 10% by mass of shell Core: vinylidene chloride / methyl acrylate / methyl methacrylate / acrylonitrile / acrylic acid = 93
/3/3/0.9/0.1 (mass%) Shell part vinylidene chloride / methyl acrylate / methyl methacrylate / acrylonitrile / acrylic acid = 8
8/3/3/3/3 (% by mass) Weight average molecular weight 38,000 Latex-B: Methyl methacrylate / styrene / 2-ethylhexyl acrylate / 2-hydroxyethyl methacrylate /
Acrylic acid = 59/9/26/5/1 (% by mass) copolymer

(3) Heat treatment for transport (3-1) Heat treatment PE thus prepared with a back / undercoat layer
The T support was placed in a heat treatment zone having a total length of 200 m set at 160 ° C. and transported at a tension of 2 kg / cm ² and a transport speed of 20 m / min. (3-2) Post-heat treatment After the heat treatment, post-heat treatment was performed by passing through a zone at 40 ° C for 15 seconds, and winding was performed. The winding tension at this time was 10 kg / cm ² .

<< Preparation of Photothermographic Material >> A slide beat coating method shown in FIG. 1 of JP-A-2000-2964 was applied onto the undercoating second layer of a PET support.
The above-mentioned image forming layer coating solution was applied so that the coated silver amount was 1.5 g / m ² . The protective layer coating solution was further coated with the solid content of the polymer latex at 1.29 g / m2.
Co-coating was carried out simultaneously with the coating solution for the image forming layer so as to obtain a coating solution of ² . Thereafter, the lower layer overcoat layer coating solution was coated on the protective layer with a polymer latex solid content of 1.97 g.
/ M ² and the upper layer overcoat layer coating solution were simultaneously and multi-layer coated together with the lower layer overcoat coating solution such that the solid latex coating amount of the polymer latex was 1.07 g / m ² , to produce a photothermographic material. Drying at the time of coating is carried out at a constant bulb process and a deceleration process at a dry bulb temperature of 70 to 75 ° C and a dew point of 8 to 2
In a range of 5 ° C. and a liquid film surface temperature of 35 ° C. to 60 ° C., a horizontal drying zone (where the support is at an angle of 1.5 ° to 3 ° with respect to the horizontal direction of the coating machine) up to the vicinity of a drying point at which the flow of the coating liquid is almost eliminated. )
I went in. Winding after drying was performed under the conditions of a temperature of 25 ± 5 ° C. and a relative humidity of 45 ± 5%, and the winding shape was adjusted to the subsequent processing form (image forming layer surface side outer winding), with the image forming layer side being outside. . Note that the envelope relative humidity of the photothermographic material is 20 to
At 40% (measured at 25 ° C.), the film surface pH on the image forming side of the obtained photothermographic material was 5.0, the Beck smoothness was 750 seconds, and the film surface pH on the opposite side was 5.9. Smoothness is 6
00 seconds.

<< Evaluation of Photographic Performance >> (Exposure Processing) A semiconductor laser having a beam diameter (FWHM of 1/2 of beam intensity) of 12.56 μm, a laser output of 50 mW, and an output wavelength of 783 nm is mounted on the obtained photothermographic material. Using the single-channel cylindrical inner surface type laser exposure apparatus described above, exposure was performed at a mirror rotation number of 60000 rpm and an exposure time of 1.2 × 10 ⁻⁸ seconds. At this time, the overlap coefficient was 0.449, and the laser energy density on the photothermographic material surface was 75 μJ / cm ² . (Heat Developing Process) The exposed photothermographic material was subjected to a heat developing process using the heat developing machine shown in FIG. The roller surface material of the thermal development processing part is silicon rubber, the smooth surface is Teflon non-woven fabric, and the line speed of transportation is 150 c.
m / min. The thermal development process is performed by
2.2 seconds (the drive systems of the preheating section and the heat development section are independent, the speed difference between the heat development section is set to -0.5% to -1%, and the temperature of the metal roller in each preheating section is The setting and time were as follows: the first roller temperature was 67 ° C., 2.0 seconds, and the second roller temperature was 82.
° C, 2.0 seconds, third roller temperature 98 ° C, 2.0 seconds, fourth roller temperature 107 ° C, 2.0 seconds, fifth roller temperature 115 ° C, 2.0 seconds, sixth roller temperature 120 ° C ,
2.0 seconds), 17.2 seconds in the heat development processing section (temperature of the surface of the photothermographic material 120 ° C.), and 13.6 seconds in the slow cooling section. The temperature accuracy in the width direction was ± 0.5 ° C. The setting of each roller temperature depends on the width of the photothermographic material (for example, width 6).
5 cm longer on both sides than 1 cm), and a temperature was applied to that portion so that the temperature accuracy was improved. In addition,
Since the temperature at both ends of each roller is drastically lowered, the portion 5 cm longer than the width of the photothermographic material is set so that the temperature is 1-3 ° C. higher than the center of the roller, and the photothermographic material (eg, width) Care was taken that the image density (within 61 cm) was a homogeneous finish.

(Evaluation Method) In both cases where the compound of the present invention was present in the light-sensitive material and in the case where the compound was not present, the light-sensitive material after development was cut into a thickness of 2 μm, and electron micrographs of the slices were taken. . For the photograph, the number of developed silver particles per unit area was measured, and the increase rate of the developed silver particle density was calculated by the following equation. Developed silver particle density increase rate (%) = (number of developed silver particles per unit area of photosensitive material containing compound of the present invention / number of developed silver particles per unit area of photosensitive material not containing compound of the present invention) × 100 Next, the covering power increase rate was calculated by the following equation. Covering power increase rate (%) = (covering power of light-sensitive material containing compound of the present invention / covering power of light-sensitive material not containing compound of the present invention) × 100 Here, covering power means all of the photosensitive material. It is a value obtained by dividing the visible density by the amount of developed silver (g / m ² ) for a sample in which silver ions have been reduced. The density measurement was performed with a Macbeth TD904 densitometer (visible density). A gamma value (the slope of a straight line connecting the densities 0.1 and 3.0, with the logarithm of the exposure amount as the horizontal axis and the density as the vertical axis) was calculated as the evaluation of the high contrast. Practically, the gamma value needs to be 10 or more, and preferably 15 or more. Next, Dmin during high-temperature storage was evaluated by the following method. Without exposure, heat development was performed in the same manner as above,
Store in a dark place at 0 ° C. and 50% relative humidity for 3 days, Dmin
Measure. ΔDmin was calculated by the following equation. Practically, ΔDmin needs to be 0.05 or less. ΔDmin = Dmin (60 ° C., 50% RH, stored for 3 days in a dark place) −Dmin (fresh) Dmin was measured with a Macbeth TD904 densitometer (visible density). Next, a heat development treatment was performed in the same manner as described above, except that the line speed of conveyance was set to 120 cm / min without performing exposure, and the number of generated black spots was visually evaluated. The evaluation results were indicated by a five-point scale of (good) 5 to 1 (bad). Practically, three or more points are required. Next, by the above-described exposure method, a 50% flat screen was output at 100 lines, and heat development was performed in the same manner as described above, and the dot quality was visually evaluated with a 200-fold loupe. The evaluation results were indicated by a five-point scale of (good) 5 to 1 (bad). Practically, three or more points are required.

Table 15 shows the results of the above evaluation.
In Table 15, the experiment No. Table 16 shows the results of measuring the above-mentioned increase rate of the developed silver particle density and the increase rate of the covering power for the samples 1, 2, 11, 12, and 13 of the present invention.

[0189]

[Table 15]

[0190]

[Table 16]

As is clear from Table 15, the sample satisfying the conditions of the present invention has a high gradation, good dot quality, small fog rise during high-temperature storage, and black spots. It turns out that it is difficult. Further, as shown in Table 16, it can be seen that the density of developed silver particles and covering power are greatly increased by the compounds of the present invention.

Example 2 Dispersion 1 shown in Table 13
S, about dispersion 1-A, immediately before adding to a coating liquid,
stroPore-PPE03 (Fuji Photo Film)
A comparative experiment was performed between the case where filtration was performed and the case where filtration was not performed. Preparation and evaluation of the photosensitive material were performed in the same manner as in Example 1. Table 17 shows the results. Here, dispersion 1
-B, Dispersion 1-C could not be filtered under the above conditions.

[0193]

[Table 17]

By performing the filtration operation, the occurrence of black spots was reduced and the fog during high-temperature storage was reduced without impairing the high contrast.

Example 3 << Preparation of Coating Solution for Image Forming Layer >> The following binder, material, and 1 mol of silver of the organic acid silver salt prepared in Example 1 were used.
Then, a silver halide emulsion was added, and water was added to obtain an image forming layer coating solution. After the preparation, vacuum degassing was performed at a pressure of 0.54 atm for 45 minutes. The pH of the coating solution is 7.3 to 7.
7. The viscosity was 40 to 50 mPa · s at 25 ° C.

[0196] The binder; SBR latex solids as 397.0g (St / Bu / AA = 68/29/3 ( wt%), using Na ₂ S ₂ O ₈ as a polymerization initiator) 1,1-bis (2 -Hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane 135.0 g as solids Organic polyhalogen compound A 40.0 g as solids Organic polyhalogen compound B 12.0 g as solids Organic polyhalogen Compound C 2.0 g as solid content Development accelerator W 5.5 g as solid content Sodium ethylthiosulfonate 0.3 g Benzotriazole 1.2 g Polyvinyl alcohol (PVA-235 manufactured by Kuraray Co., Ltd.) 10.8 g 6-isopropyl lid Razine 13.0 g Compound Z 9.6 g as solid content Compound C 0.2 g Compound of the present invention (shown in Table 13) Solid content 7.5 g Dye A (added as a mixture with low molecular weight gelatin having an average molecular weight of 15,000) Coating amount at which the optical density at 783 nm becomes 0.3 (as a guide, solid content: 0.40 g) Silver halide emulsion: 0 as Ag amount 0.06 mol Compound A as a preservative 40 ppm in the coating solution (2.5 mg / m ² as coating amount) 1% by mass as the total solvent amount in the coating solution of methanol ² % by mass as the total solvent amount in the coating solution of ethanol Was used as NaOH. (The glass transition temperature of the coating film was 17 ° C.)

<< Preparation of Coating Solution for Lower Protective Layer >> Methyl acrylate / methyl methacrylate = 70/30 (weight ratio, average particle diameter 110 nm, weight average molecular weight 800,00)
0) polymer latex solution (copolymer glass transition temperature 30 ° C., solid content concentration 28.0%, compound A 100
Water was added to 900 g of
g, polyvinyl alcohol (Kuraray Co., Ltd., PVA-
235) was added, and water was further added to prepare a coating liquid (containing 0.5% by mass of a methanol solvent). After the preparation, vacuum degassing was performed at a pressure of 0.47 atm for 60 minutes. The coating solution has a pH of 5.2 and a viscosity of 35 mPa at 25 ° C.
-It was s.

<< Preparation of Coating Solution for Upper Protective Layer >> Methyl acrylate / methyl methacrylate = 70/30 (weight ratio, average particle size 110 nm, weight average molecular weight 800,00)
0) in 900 g of a polymer latex solution (copolymer, glass transition temperature: 30 ° C., solid content: 28.0%, compound A: 100 ppm), carnava wax (manufactured by Chukyo Yushi Co., Ltd., Cellosol 524, silicone) The content is less than 5 ppm).
g, 0.3 g of compound C, 1.2 g of compound E, 25.0 g of compound F, 6.0 g of compound H, matting agent (polystyrene particles, average particle diameter 7 μm, coefficient of variation of average particle diameter 8)
%) And 40.0 g of polyvinyl alcohol (manufactured by Kuraray Co., Ltd., PVA-235), and further added water to prepare a coating solution (containing 1.5% by mass of a methanol solvent). After the preparation, the reaction was performed at a pressure of 0.47 atm for 60 minutes. The coating solution has a pH of 2.4 and a viscosity of 35 at 25 ° C.
mPa · s.

<< Preparation of Photothermographic Material >> A slide glass shown in FIG. 1 of JP-A-2000-2964 is placed on an undercoat layer of a PET support coated with an undercoat layer as described in Example 1. The coating solution for the image forming layer was coated with the above-mentioned coating solution for the lower layer of the protective layer so that the coating amount of the polymer latex was 1.5 g / m ² by using a coating method. 1.0 g / m ² , and further, the protective layer upper layer coating solution described above is coated with the image forming layer and the lower layer of the protective layer so that the solid content of the polymer latex is 1.3 g / m ^2. The upper three layers were simultaneously coated. The drying conditions at the time of coating are as follows: the first drying zone (low-speed air drying area) has a dry bulb temperature of 70 to 75 ° C, a dew point of 9 to 23 ° C, an air velocity of 8 to 10 m / s on the support surface, and a liquid film surface temperature of 35 to Drying was performed at a temperature of 40 ° C., and a second drying zone (high-speed air drying area) was dried at a dry bulb temperature of 65 to 70 ° C., a dew point of 20 to 23 ° C., and a wind speed of 20 to 25 m / s on the surface of the support. The residence time in the first drying zone was 2/3 of the constant-rate drying period in this zone, and the zone was moved to the second drying zone and dried. The first drying zone is a horizontal drying zone (the support is at an angle of 1.5 ° to 3 ° with respect to the horizontal direction of the coating machine). The coating speed is
The test was performed at 60 m / min. Winding after drying is temperature 25 ±
The test was performed at 5 ° C. and a relative humidity of 45 ± 10%. The winding shape is adjusted to the subsequent processing form (image forming layer surface side winding)
The image forming layer side was outside. The wrapping humidity of the photosensitive material was 20 to 40% relative humidity (measured at 25 ° C.), the film surface pH on the image forming side of the obtained photothermographic material was 5.1, and the Bekk smoothness was 5000 seconds. The pH of the opposite membrane surface is 5.
9. The Beck smoothness was 500 seconds.

Example 1 except that the coating method was changed
A sample was prepared and evaluated in the same manner as in Example 1.
Similarly to the above, the sample of the configuration of the present invention showed good performance.

<Example 4> A coating solution for a lower protective layer was prepared in the same manner as in Example 3. The coating solution for the upper protective layer was prepared in exactly the same manner as in Example 2 except that 5.0 g of polystyrene particles having an average particle diameter of 11 μm (coefficient of variation of the average particle diameter of 8%) was used as a matting agent. On a subbing layer of a PET support coated with a subbing layer as described in Example 1,
Using the slide bead coating method shown in FIG. 1 of JP-A-2000-2964, the above-mentioned image forming layer coating solution was coated thereon such that the coating silver amount became 1.5 g / m ^2. The protective layer lower layer coating solution is further coated with the polymer latex so that the solid content of the polymer latex is 1.2 g / m ² . as becomes 4g / m ^2, the image forming layer and the protective layer lower and upper three layers were simultaneously multilayer coated.

The drying conditions and winding appearance at the time of coating were the same as in Example 2, and the image forming layer surface side was set to the outside in accordance with the subsequent processing mode (image forming layer surface side outer winding). The envelope relative humidity of the photosensitive material was 20 to 40% (measured at 25 ° C.), the film surface pH on the image forming side of the obtained photothermographic material was 5.1, and the Beck smoothness was 1300 seconds. The pH of the opposite membrane surface is 5.
9. The Beck smoothness was 500 seconds. The sample thus obtained was evaluated in the same manner as in Example 1. As a result, the sample having the structure of the present invention showed good performance as in Example 1.

Example 5 The photosensitive materials prepared in Examples 1, 2, 3 and 4 were used in DRY SYSTEM PROCE.
When heat development was carried out using SOR FDS-6100X (manufactured by Fuji Photo Film Co., Ltd.), Examples 1, 2, 3
Samples having the configuration of the present invention similarly to Examples 4 and 4 showed good performance.

[0204]

According to the production method of the present invention, the density of developed silver particles, the covering power are high, the gradation is high,
Good dot quality, small fog rise during high temperature storage,
Further, it is possible to obtain a photothermographic material which is most suitable for photolithography, in which black spots are less likely to occur. Further, according to the production method of the present invention, a photothermographic material can be produced by aqueous coating which is advantageous in terms of environment and cost.

[Brief description of the drawings]

FIG. 1 is a cross-sectional electron micrograph showing a case where a compound of the present invention is present in a photothermographic material (A) and a case where it is not present (B).

FIG. 2 is a side view showing a configuration example of a heat developing machine used for a heat development process of the photothermographic material of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 heat-developed image forming material 11 carry-in roller pair 12 carry-out roller pair 13 roller 14 smooth surface 15 heating heater 16 guide plate A preheating section B heat development processing section C slow cooling section

Claims (7)

[Claims] 1. A non-photosensitive organic silver salt, a light-sensitive silver halide, a reducing agent for silver ions, a binder, and a development start point on and near the non-photosensitive organic silver salt on one side of a support. A method for producing a photothermographic material containing a compound capable of forming a chemical species capable of forming an image in an imagewise manner,
When a layer containing a compound that generates a chemical species capable of forming a development start point on and near a non-photosensitive organic silver salt is formed on a support, the compound is dispersed in solid fine particles satisfying both of the following conditions: A method for producing a photothermographic material, comprising adding a coating solution to a coating solution, applying the coating solution, and drying. (1) Average particle size is 0.05 μm to 1.0 μm (2) Volume ratio of particles having a particle size of 3 μm or more is 5% or less 2. Developed silver by adding, on one side of a support, a non-photosensitive organic silver salt, a photosensitive silver halide, a reducing agent for silver ions, a binder, and 0.01 mol / mol of silver. A method for producing a photothermographic material containing a compound whose particle density increases from 200 to 5000%, wherein the compound whose development silver particle density increases from 200 to 5000% by adding 0.01 mol / silver mol is used. Forming a layer containing the compound on a support, adding the compound to a coating solution as a solid fine particle dispersion satisfying both of the following conditions, and applying and drying the coating solution: Method. (1) Average particle size is 0.05 μm to 1.0 μm (2) Volume ratio of particles having a particle size of 3 μm or more is 5% or less 3. A covering power of 120 by adding a non-photosensitive organic silver salt, a photosensitive silver halide, a reducing agent for silver ions, and 0.01 mol / silver mol on one surface of a support. A method for producing a photothermographic material containing a compound which is increased to
When a layer containing a compound whose covering power is increased to 120 to 1000% by adding at 1 mol / silver mol is formed on a support, the compound is added to a coating solution as a solid fine particle dispersion satisfying both of the following conditions. And applying the coating solution and drying the coating solution. (1) Average particle size is 0.05 μm to 1.0 μm (2) Volume ratio of particles having a particle size of 3 μm or more is 5% or less 4. The method for producing a photothermographic material according to claim 1, wherein the solid fine particle dispersion contains a preservative. 5. The method for producing a photothermographic material according to claim 4, wherein a preservative concentration in the solid fine particle dispersion is 500 ppm or less. 6. The method according to claim 1, wherein 85% or more of coarse particles having a particle diameter of 3 μm or more present in the solid fine particle dispersion are removed by filtration before adding the solid fine particle dispersion to the coating solution. A method for producing the photothermographic material according to claim 1. 7. The method according to claim 1, wherein prior to adding the solid fine particle dispersion to a coating liquid, 98% or more of coarse particles having a particle diameter of 3 μm or more present in the solid fine particle dispersion are removed by filtration. A method for producing the photothermographic material according to claim 6.