JP2000007683A - Preparation of silver salt of fatty acid and heat developing photosensitive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for preparing a silver salt of a fatty acid having antifogging ability when used as a heat developing photosensitive material and antifogging ability with time and excellent in image stability after subjected to heat developing treatment, and to obtain a heat developing photosensitive material having excellent performance by using such a silver salt of fatty acid. SOLUTION: This silver salt of a fatty acid is obtained by preparing (1) an aqueous solution containing silver ion or a mixed solution of water and a 4-6C tertiary alcohol and (2) a mixed solution of an aqueous solution of an alkaline metal salt of a fatty acid and a 4-6C tertiary alcohol, then, adding the solution (1) and the solution (2) at the same time and mixing them to form the objective silver salt of fatty acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for preparing a fatty acid silver salt for use in a photothermographic material (hereinafter sometimes referred to as a photothermographic material) and a photothermographic material using the fatty acid silver salt. It is.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand in the medical field to reduce the amount of waste liquid from the viewpoint of environmental protection and space saving. Therefore, a photosensitive heat for medical diagnostics and photographic technology can be efficiently exposed by a laser imagesetter or a laser imager, and can form a sharp black image having high resolution and sharpness. There is a need for technology for developed photographic materials. These photothermographic materials can eliminate the use of solution processing chemicals and provide a simpler and more environmentally friendly thermal development system to customers.

[0003] A method of forming an image by thermal development is described in, for example, US Patents 3,152,904 and 3,457,075, and Morgan and B.A. Shely
"Thermal Processed Silver System (Thermally
Processed Silver Systems "(imaging Processesand Materials)
Materials) Neblette 8th edition, Sturge,
V. Walworth, A .; Shep
p) Edit, page 2, 1969).

[0004] Such photosensitive materials include 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, usually in an organic binder matrix. It is contained in a dispersed state.
The photosensitive material is stable at room temperature, but after exposure to high temperature (for example,
When heated to 80 ° C. or higher), silver is produced through a redox reaction between a reducible silver source (which functions as an oxidizing agent) and a reducing agent. This oxidation-reduction reaction is promoted by the catalytic action of the latent image generated by the exposure. The silver formed by the reaction of the reducible silver salt in the exposed areas provides a black image, which contrasts with the unexposed areas, resulting in the formation of an image.

The silver source used in such a system is generally a silver salt of a fatty acid, and various production methods are known. For example, JP-A-49-93310, JP-A-49-93310
94619 and JP-A-53-68702, a method of preparing an organic silver salt in a coexisting solution of water and a poorly water-soluble solvent, JP-A-53-31611 and JP-A-54-411.
No. 7, and JP-A-54-46709, a method for preparing an organic silver salt in an aqueous solution, and JP-A-57-1867.
No. 45, JP-A-47-9432 and US-3700.
No. 458, a method of preparing an organic silver salt in an organic solvent, and the like. Basically, the fatty acid is heated and melted in water at a temperature higher than its melting point, sodium hydroxide or an alkali metal salt is added with vigorous stirring, and then silver nitrate is added to replace the alkali soap with silver soap.

[0006] Such an alkali soap forms micelles in an aqueous solution, and is apparently a cloudy liquid. Such a reaction from the micellar state to silver soap often causes production stability problems. For this reason, as a method for making the alkaline soap a homogeneous solution, it has been proposed to use a mixed solution of water and alcohol as the solvent.
No. 607.

[0007] Alkali soap exhibits alkalinity as its name implies. Therefore, in this case, the silver soap will be made at a high pH. However, the addition of silver nitrate to an alkaline solution produces silver oxide as a by-product, and has a high reducing property due to the high pH of unintended and unintended trace contamination of reducing substances at high pH. This results in unintended silver nuclei. Such by-products are very disadvantageous in the performance of the heat-developable photographic material using the same, particularly in that undesired fogging is caused. However, from the above viewpoint, the fogging problem is not solved even by the method described in JP-A-55-40607 for the purpose of obtaining a uniform liquid in order to suppress the generation of by-products.

Japanese Patent Application Laid-Open No. 9-127643 discloses a method for forming a silver salt by simultaneous metered addition of an alkali metal salt and a silver nitrate solution, and a mixed solution of sodium behenate in water, isopropyl alcohol, and a silver nitrate solution. There is a description of simultaneous addition of. This method can reduce the reaction under high pH to a neutral range at least, and is a preferable method to reduce the amount of silver oxide formed.However, isopropyl alcohol is also reducing, and in this respect, fog is completely solved. There is no way to do that.

As described above, attention must be paid to the preparation of the fatty acid silver salt, and it is necessary to eliminate as much of the reducing substance as possible during the formation of the fatty acid silver salt, but this has not been achieved by conventional methods.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fatty acid which has an antifogging function when used in a photothermographic material and further has an antifogging function over time, and which is excellent in image stability after heat development. An object of the present invention is to provide a method for preparing a silver salt, and a method for preparing a fatty acid silver salt capable of improving the quality of a coated surface. It is another object of the present invention to provide a photothermographic material having excellent performance by using such a fatty acid silver salt.

[0011]

This object has been achieved by the following means. (1) An aqueous solution containing silver ions, or a mixed solution of water and a tertiary alcohol having 4 to 6 carbon atoms, and water and 4 carbon atoms of an alkali metal salt of a fatty acid having a concentration of 7% to 50% by weight 6. A method for preparing a silver salt of a fatty acid, which comprises preparing a mixed solution with a tertiary alcohol, and adding and mixing the liquid and the liquid simultaneously to form a silver salt of a fatty acid. (2) The method for preparing a fatty acid silver salt according to the above (1), wherein the fatty acid is a saturated fatty acid having a carbon number of substantially 12 to 26. (3) The method for preparing a silver salt of a fatty acid according to the above (1) or (2), further comprising a step of desalting after forming a silver salt of a fatty acid. (4) A silver salt of a fatty acid is converted into an aqueous dispersion, and the aqueous dispersion is converted into a high-speed stream at a high pressure, and then subjected to a step of reducing the pressure to obtain a fine aqueous dispersion, which is described in any of (1) to (3) above. Preparation method of fatty acid silver salt. (5) A photothermographic material containing a silver salt of a fatty acid prepared in any one of the above (1) to (4), and having a photosensitive image forming layer containing a photosensitive silver halide, a reducing agent and a binder. (6) During the preparation of the fatty acid silver salt and immediately before the coating,
(5) The thermal development according to the above (5), which has a photosensitive image forming layer formed using a photosensitive image forming layer coating solution to which a metal ion selected from Ca, Mg, Ce, Al, Zn and Ba is added in a non-halide form. Photosensitive material. (7) The photothermographic material according to the above (5) or (6), wherein a polymer latex is used as a binder.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The silver salt of a fatty acid in the present invention includes an aqueous solution containing silver ions or a mixed solution of water and a tertiary alcohol having 4 to 6 carbon atoms;
No. 6 mixed solutions with tertiary alcohols are prepared, and these two solutions are simultaneously added and mixed. By using such a preparation method, a uniform reaction can be performed without generating undesirable by-products such as silver oxide and silver nuclei. For this reason, the photothermographic material containing the thus prepared fatty acid silver salt in the image forming layer has low fog and excellent photographic performance. In addition, storage stability and image stability are good. On the other hand, in a preparation method in which a reaction is performed by adding a silver nitrate solution to a solution of an alkali metal salt of a fatty acid, generation of by-products is not suppressed,
This leads to an increase in fog, resulting in poor storage stability. Also, when a solvent other than the above is used as a solvent other than water,
As will be described later, compatibility with water cannot be ensured, or the generation of by-products cannot be suppressed, so that good performance cannot be obtained when the photothermographic material is used.

In the present invention, a silver salt of a saturated fatty acid having 12 to 26 carbon atoms is particularly preferably used as the fatty acid silver salt as described later, and therefore, the fatty acid is particularly preferably substantially in the range of 12 to 26. . The term “substantially” as used herein means that the total content of fatty acids having less than 12 carbon atoms and 27 or more carbon atoms is preferably 5% by weight or less, more preferably 5% by weight or less, based on the total weight of fatty acids used as fatty acid silver salts. Preferably, it is 2 wt% or less.

Further, in the present invention, in order to reduce fog and to prevent film formation of the binder after coating, it is preferable to desalt a fatty acid silver salt formed using a liquid and a liquid. .

Furthermore, in order to improve the coated surface condition of the photothermographic material, an aqueous dispersion of a fatty acid silver salt is obtained, which is converted into a high-speed stream at a high pressure, and then reduced in pressure to reduce the fine aqueous dispersion. It is preferable that In this case, the dispersion medium is preferably water alone, but may contain an organic solvent if it is 20% by weight or less.

The photothermographic material of the present invention contains the above-mentioned fatty acid silver salt in the image forming layer. In order to further improve the image storability after image formation, the fatty acid silver salt is prepared. , Ca, Mg, Ce,
It is preferable to use an image forming layer coating solution to which a metal ion selected from Al, Zn and Ba is added in a non-halide form. In addition, addition with a halide is accompanied by an increase in fog or deterioration of image preservability.

The metal salt in the light-sensitive material may be used in combination with calcium or magnesium behenate at the time of coating as described in GB-1498406, zinc, cadmium or the like described in JP-A-47-319. A method in which a copper acetate compound is added at the time of coating, palladium described in JP-A-51-51323 and the like can be mentioned. However, these prior arts are based on the premise that the coating is carried out with a coating solution using an organic solvent as a solvent, and the method itself is impossible or ineffective with an intended aqueous solvent system. JP-A-52-24520 describes that a cerium compound is added at the time of preparing a silver salt to improve raw storage stability and image discoloration resistance. However, this prior art also requires coating with an organic solvent. It describes the effect of a fatty acid silver salt prepared by a conventional method as a premise. Application to a silver salt of a fatty acid formed by a conventional method has little effect on image discoloration resistance to light (room light or sunlight) of a photosensitive material. Furthermore, the addition of these metal salts in the form of halides further impairs the above-mentioned properties,
Only products with low commercial value could be made.

Further, the image forming layer includes a fatty acid silver salt,
It is preferable that the photosensitive image-forming layer contains a photosensitive silver halide, a reducing agent and a binder. As the binder, it is possible to perform aqueous coating using water as a main solvent, which is advantageous in terms of environment and cost, and In order to obtain good silver tone and photographic performance, it is preferable to use a polymer latex.

The liquid used in the present invention, that is, an aqueous solution containing silver ions or a mixed solution of water and a predetermined organic solvent is an acidic liquid. Specifically, it is a liquid having a pH of 6 or less, preferably a pH of 2 to 6 and more preferably p.
H is 3.5 or more and 6 or less.

Any acid and alkali can be added to the liquid for pH adjustment.

The silver ion concentration in the solution of the present invention is arbitrarily determined, but is preferably from 0.03 mol / l to 6.5 mol / l, more preferably from 0.1 mol / l to 0.1 mol / l.
It is not less than ol / l and not more than 5 mol / l.

The liquid used in the present invention may contain a tertiary alcohol having 4 to 6 carbon atoms as a solvent. In that case, the amount used is 70
% Or less, preferably 50% or less.

The fatty acid used in the liquid used in the present invention, that is, the mixed solution of an aqueous solution of an alkali metal salt of a fatty acid and a tertiary alcohol having 4 to 6 carbon atoms, is relatively stable to light when formed into a silver salt. At 80 ° C in the presence of an exposed photocatalyst (such as a latent image of photosensitive silver halide) and a reducing agent.
Alternatively, it is a silver salt that forms a silver image when heated to a higher temperature. Fatty acids are in particular long-chain fatty carboxylic acids having 10 to 30, preferably 12 to 26 carbon atoms. Preferred examples of the aliphatic carboxylic acids include cerotic acid, lignoceric acid, behenic acid, erucic acid, arachidic acid, stearic acid, oleic acid, lauric acid, caproic acid, myristic acid, palmitic acid, maleic acid, fumaric acid, and tartaric acid. , Linoleic, butyric and camphoric acids, and mixtures thereof.

The alkali metal of the alkali metal salt of a fatty acid used in the liquid used in the present invention is specifically Na or K. Alkali metal salts of fatty acids are prepared by adding NaOH or KOH to the fatty acids. At this time,
It is preferable to make the amount of alkali less than or equal to the amount of fatty acid so that unreacted fatty acid remains. In this case, the amount of the residual fatty acid is 3 mol% or more and 50 mo per 1 mol of the total fatty acid.
1% or less, preferably 3 mol% or more and 30 mol or less.
% Or less. Alternatively, after the alkali is added in a desired amount or more, an acid such as nitric acid or sulfuric acid may be added to neutralize the excess alkali.

The pH of the solution can be adjusted according to the required properties of the silver salt of fatty acid. For adjusting the pH, any acid or alkali can be used.

Further, the liquid and the liquid used in the present invention,
Alternatively, the liquid in the reaction vessel to which the liquid and the liquid are added,
For example, a compound represented by the general formula (1) in JP-A-62-65035, a water-soluble group-containing N heterocyclic compound as described in JP-A-62-150240, Inorganic peroxides as described in JP-A-101019, sulfur compounds as described in JP-A-51-78319, disulfide compounds as described in JP-A-57-643, and hydrogen peroxide can be added.

The liquid used in the present invention must be a mixed solvent of a tertiary alcohol having 4 to 6 carbon atoms and water in order to obtain a uniform liquid. If the carbon number exceeds this, there is no compatibility with water, which is not preferable. Of the tertiary alcohols having 4 to 6 carbon atoms, tert-butanol, which is most compatible with water, is most preferred. Alcohols other than the tertiary alcohol are reducing as described above, and are harmful to the formation of the silver salt of the fatty acid. 3rd used in combination with liquid
The alcohol amount is 3% or more and 70% or less, preferably 5% or more and 50% or less as a solvent volume with respect to the volume of water in the liquid.

The concentration of the alkali metal salt of the fatty acid in the solution used in the present invention is, as a weight ratio, not less than 7 wt% and not more than 50 wt%.
Or less, preferably 7 wt% or more and 45 wt% or less, and more preferably 10 wt% or more and 40 wt% or less.

A photothermographic material using a fatty acid silver salt prepared using a solution having a concentration of less than 7% by weight is liable to cause fogging during storage over time, and is not preferable in performance. When the concentration is 5
If it exceeds 0% by weight, the viscosity of the liquid is too high, and there is a problem in the feeding of the liquid, which is not preferable in production.

In the present invention, a desired fatty acid silver salt is prepared by simultaneously adding the liquid and the liquid. Simultaneous addition in this case means that 50 vol% or more of the total amount is simultaneously added, but it is preferable that 75 vol% or more is simultaneously added. When any of them is added in advance, it is preferable to add the liquid first.

The liquid and the liquid of the present invention can be adjusted to an appropriate temperature for controlling the required performance of the fatty acid silver salt, for example, the particle size. The temperature of the liquid is preferably from 5 ° C. to 60 ° C., more preferably from 10 ° C. to 50 ° C. for the purpose of ensuring the stability of the liquid. The temperature of the liquid is preferably 50 ° C. or more and 90 ° C. or less, more preferably 60 ° C. or more and 85 ° C. or less, for the purpose of maintaining a certain temperature necessary for avoiding the phenomenon of crystallization and solidification of the alkali soap.

The temperature of the reaction solution during silver salt formation may be any temperature, but is preferably 5 ° C. or more and 75 ° C. or less, more preferably 10 ° C. or more and 50 ° C. or less, so that the performance as a photographic light-sensitive material is improved. It can be further improved.

The apparatus used for silver salt formation is not limited.
In particular, as the stirring device, any method such as a bulk stirring type such as an anchor blade and a paddle blade, an emulsification dispersion type such as a dissolver and a homogenizer, or a combination thereof can be used. Water is used as the solvent previously placed in the reaction vessel, but a liquid and a mixed solution with a tertiary alcohol used in the liquid are also used.

The method of adding the liquid and the liquid is, for example, addition to the liquid surface, addition to the liquid by inserting an addition port into the liquid, addition of a shower, and further, providing a reaction field in the reaction liquid. Any method such as a method of adding it can be used.

The liquid and the time for adding the liquid can also be arbitrarily selected. For example, the addition can be performed by a method of adding at a constant addition rate, an accelerated addition method or a deceleration addition method using an arbitrary time function.

An aqueous medium-soluble dispersing agent can be added to the liquid and the liquid or reaction liquid used in the present invention. Any dispersing agent may be used as long as the formed fatty acid silver salt can be dispersed. A specific example is
It is in accordance with the description of the fatty acid silver salt dispersion aid described below.

The shape of the fatty acid silver salt that can be used in the present invention is not particularly limited. Generally, for example, M
arcel Dekker Published in 1991, ASDiamon
Fig. d on page 45 of Handbook of Imaging Materials
It is widely known to have a needle-like shape having a short axis and a long axis as described in 2.2.
Particles having no selective growth direction as described in No. 643 may be used.

When the fatty acid silver salt prepared in the present invention has needle-like crystals, the minor axis is preferably from 0.01 μm to 0.50 μm, the major axis is preferably 0.10 μm to 5.0 μm, and the minor axis is 0.01 μm or more.
More preferably, it is 0.40 μm or less, and the major axis is 0.10 μm or more and 4.0 μm or less. In the case of having a crystal having no selective growth direction, the average particle size is preferably 0.01 μm or more and 5 μm or less, more preferably 0.01 μm or more and 4 μm or less. The fatty acid silver salt preferably has a monodisperse particle size distribution. Monodispersion is the percentage of the standard deviation of the particle diameter (the length of the minor axis and major axis for needle-like crystals) divided by the particle diameter (the minor axis and major axis of needle-like crystals, respectively). But preferably 10
It is at most 0%, more preferably at most 80%, even more preferably at most 50%. As another method of measuring the monodispersity, there is a method of obtaining the standard deviation of the volume-weighted average diameter of the fatty acid silver salt, the percentage of the value divided by the volume-weighted average diameter (coefficient of variation) is preferably 100% or less, more It is preferably at most 80%, more preferably at most 50%. As a measuring method, for example, the particle size (volume weighted average diameter) obtained by irradiating a laser beam to a fatty acid silver salt dispersed in a liquid and obtaining an autocorrelation function with respect to a time change of fluctuation of the scattered light is obtained. Can be.

In the method for preparing a fatty acid silver salt of the present invention, it is preferable to perform a desalting / dehydrating step after the formation of the silver salt. The method is not particularly limited, and known and commonly used means can be used. For example, known filtration methods such as centrifugal filtration, suction filtration, ultrafiltration, floc-forming water washing by a coagulation method,
Supernatant removal by centrifugal sedimentation or the like is also preferably used. The desalting / dehydration may be performed once or plural times. The addition and removal of water may be performed continuously or individually. The desalting / dehydration is performed so that the conductivity of the finally dehydrated water is preferably 300 μS / cm or less, more preferably 100 μS / cm or less, and most preferably 60 μS / cm or less. The lower limit of the conductivity in this case is not particularly limited, but is usually about 0.5 μS / cm.

The silver salt of a fatty acid prepared by the method of the present invention comprises
It can be used in a photothermographic material used together with a reducing agent, photosensitive silver halide and a binder.

Conventionally, most of the photothermographic materials of the type using a fatty acid silver salt form an emulsion layer by applying a coating solution using an organic solvent such as toluene, methyl ethyl ketone or methanol as a solvent. . The use of an organic solvent as a solvent is extremely disadvantageous in terms of safety in the manufacturing process, adverse effects on human bodies, and cost for collecting the solvent and the like.

For this reason, a method of forming a photosensitive layer using a coating solution of an aqueous solvent has been considered.

For example, JP-A-49-52626 and JP-A-53-116144 disclose examples using gelatin as a binder. Also, Japanese Patent Laid-Open No. 50-151
No. 138 describes an example using polyvinyl alcohol as a binder.

Further, JP-A-60-61747 discloses that
An example in which gelatin and polyvinyl alcohol are used in combination is described. Another example is disclosed in Japanese Patent Application Laid-Open No. 58-28737.
JP-A No. 195/1992 describes an example of a photosensitive layer using a water-soluble polyvinyl acetal as a binder.

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

However, when the above polymer is used as a binder, the compatibility with the fatty acid silver salt is poor, so that a coated material which can be practically used due to the quality of the coated surface cannot be obtained. Phenomena such as brown or yellow, fog, etc., which were far apart, occurred, and only those which significantly impaired the commercial value were obtained.

To solve such a problem, European Patent No. 80
3764A1 and JP-A-10-62899 describe examples in which a hydrophobic polymer is used as a latex dispersed in an aqueous solvent. In order to obtain a coating surface quality that can withstand practical use with an aqueous solvent coating solution containing such a fatty acid silver salt,
It is necessary to keep the fatty acid silver salt finely dispersed without aggregation in an aqueous solvent. Therefore, it is necessary to develop a method for dispersing the fatty acid silver salt in fine particles.

The method of dispersing the fatty acid silver salt in the form of fine particles can be carried out by a known means for making fine particles in the presence of a dispersing agent (eg, a high-speed mixer, a homogenizer, a high-speed impact mill, a Banbury mixer, a homomixer, a kneader, a ball mill, a vibrating ball mill). , Planetary ball mill, attritor, sand mill,
It can be dispersed mechanically using a bead mill, colloid mill, jet mill, roller mill, tron mill, high-speed stone mill).

The fatty acid silver salt which can be used in the present invention is used for obtaining fine particles having a small particle size and no aggregation.
A method of forming a solid fine particle dispersion using a dispersant is used. It is preferable to use a dispersion method in which the aqueous dispersion of the fatty acid silver salt obtained by the method of the present invention is converted into a high-pressure and high-speed flow, and then the pressure is reduced.

Further, when a photosensitive silver salt is present at the time of dispersion, fog increases and the sensitivity is remarkably reduced. Therefore, it is more preferable that the photosensitive silver salt is not substantially contained at the time of dispersion. In the present invention, the amount of the photosensitive silver salt in the aqueous dispersion to be dispersed is 0.1 mol% or less based on 1 mol of the fatty acid silver salt in the liquid, and the photosensitive silver salt is not actively added. Things.

In the present invention, the dispersing apparatus and the technique used to carry out the above redispersion method are described in, for example, "Dispersion Rheology and Dispersion Technique" (Toshio Kajiuchi and Hiroki Usui, 1991, Shinzansha Publishing Co., Ltd., p
357-403), "Progress in Chemical Engineering Vol. 24," edited by The Society of Chemical Engineers, Tokai Branch, 1990, Maki Shoten,
184-185), JP-A-59-49832, U.S. Pat. No. 4,533,254, JP-A-8-137444, JP-A-8-238848, JP-A-2-261525,
As described in detail in JP-A-1-94933 and the like, the redispersion method of the present invention is provided in a pipe after an aqueous dispersion containing at least a fatty acid silver salt is pressurized by a high-pressure pump or the like and sent into the pipe. This is a method in which fine dispersion is performed by passing through a fine slit and then causing a sharp drop in pressure in the dispersion.

The high-pressure homogenizer to which the present invention relates is generally (a) a "shearing force" generated when the dispersoid passes through a narrow gap at a high pressure and a high speed, and (b) a dispersoid is changed from a high pressure to a normal pressure. It is considered that dispersion into fine particles is performed by dispersing force such as “cavitation force” generated when the particles are released. An example of this type of dispersing device is a Gaulin homogenizer.In this device, the liquid to be dispersed sent at high pressure is converted into a high-speed flow through a narrow gap on the cylindrical surface, and the force is applied to the surrounding wall by the force. The particles collide and are emulsified and dispersed by the impact force. Working pressure is generally 1
00~600kg / cm ^2, the flow rate is in the range of a few M～30m / sec, be devised that the high-speed flow portion in order to increase the dispersion efficiency was devised such increasing the number collisions in the saw-toothed I have. On the other hand, devices capable of dispersing at higher pressures have been developed in recent years, and typical examples thereof include a microfluidizer (Microfluidics International Corporation) and a nanomizer (Tokusai Kika Kogyo Co., Ltd.) ).

The fatty acid silver salt of the present invention can be dispersed in a desired particle size by adjusting the flow rate, the differential pressure at the time of pressure drop, and the number of treatments. However, from the viewpoint of photographic characteristics and particle size, the flow rate can be reduced. 200 m / sec to 600 m / sec, the pressure difference at the time of pressure drop is preferably 900 to 3000 kg / cm ² , and the flow rate is 300 m / sec to 600 m / sec, and the pressure difference at the time of pressure drop is 1500 to 3000 kg / cm ^2. More preferably, it is within the range. The number of times of the distributed processing can be selected as needed. Usually, the range of 1 to 10 times is selected, but from the viewpoint of productivity, about 1 to 3 times is selected. It is not preferable to raise the temperature of such an aqueous dispersion under high pressure from the viewpoint of dispersibility and photographic properties. At a temperature higher than 90 ° C., the particle size tends to increase and fog tends to increase. is there. Therefore, in the present invention, the high pressure, the step before converting to high-speed flow, or the step after the pressure is reduced,
Alternatively, a cooling device is included in both of these steps, and the temperature of such water dispersion is preferably maintained in the range of 5 ° C to 90 ° C by the cooling step, and more preferably 5 ° C to 80 ° C.
It is preferable that the temperature is kept in the range of 5 ° C., particularly 5 ° C. to 65 ° C. In particular, at the time of high-pressure dispersion in the range of 1500 to 3000 kg / cm ² , it is effective to provide the above cooling step. The cooling device has two
Those using a static mixer for a heavy pipe or a triple pipe, a multi-tube heat exchanger, a coiled-tube heat exchanger, and the like can be appropriately selected. In addition, in order to increase the efficiency of heat exchange, it is only necessary to select a suitable one such as a pipe thickness, a wall thickness and a material in consideration of a working pressure. Refrigerant used for the cooler, from the amount of heat exchange,
Well water at 20 ° C., cold water at 5 to 10 ° C. treated with a refrigerator, or a refrigerant such as ethylene glycol / water at −30 ° C. can be used if necessary.

When the fatty acid silver salt is formed into solid fine particles using a dispersant, for example, polyacrylic acid, a copolymer of acrylic acid, a maleic acid copolymer, a maleic acid monoester copolymer, and acryloylmethyl Synthetic anionic polymers such as propanesulfonic acid copolymers, semi-synthetic anionic polymers such as carboxymethyl starch and carboxymethyl cellulose, anionic polymers such as alginic acid and pectic acid, and JP-A-52-92716 and WO88 / 04794. Anionic surfactants described, compounds described in Japanese Patent Application No. 7-350753, or known anionic, nonionic, cationic surfactants and other polyvinyl alcohol, polyvinylpyrrolidone, carboxymethylcellulose, hydroxypropylcellulose, Known such as hydroxypropyl methylcellulose Or a naturally occurring polymer compound such as gelatin or the like can be appropriately selected and used.

It is a general method that the dispersing aid is mixed with a fatty acid silver salt powder or a fatty acid silver salt in a wet cake state before dispersion and then sent as a slurry to a dispersing machine.
Heat treatment or treatment with a solvent may be performed in a state of being mixed with the fatty acid silver salt in advance to obtain a fatty acid silver salt powder or a wet cake. The pH may be controlled by a suitable pH adjuster before, during or after dispersion.

In addition to the mechanical dispersion, the dispersion may be roughly dispersed in a solvent by controlling the pH, and then the fine particles may be formed by changing the pH in the presence of a dispersing agent. At this time, a fatty acid solvent may be used as a solvent used for the coarse dispersion, and the organic solvent is usually removed after the completion of the fine particle formation.

The prepared dispersion may be stored with stirring for the purpose of suppressing sedimentation of fine particles during storage, or stored in a highly viscous state by a hydrophilic colloid (for example, in a jelly state using gelatin). You can also do.
Further, a preservative can be added for the purpose of preventing the propagation of various bacteria during storage.

The particle size (volume-weighted average diameter) of the fatty acid silver salt solid fine particle dispersion of the present invention can be determined, for example, by irradiating the solid fine particle dispersion dispersed in a liquid with a laser beam and changing the fluctuation of the scattered light with time. Can be determined from the particle size (volume weighted average diameter) obtained by obtaining the autocorrelation function for The average particle size is preferably 0.05 μm or more and 10.0 μm or less. More preferably, the average particle size is from 0.1 μm to 5 μm, and still more preferably, the average particle size is from 0.1 μm to 2.0 μm.

The particle size distribution of the fatty acid silver salt solid fine particle dispersion is preferably monodispersed. Specifically, the percentage (coefficient of variation) of the value obtained by dividing the standard deviation of the volume-weighted average diameter by the volume-weighted average diameter is 80% or less, more preferably 5% or less.
0% or less, more preferably 30% or less.

The fatty acid silver salt solid fine particle dispersion in the present invention comprises at least a fatty acid silver salt and water. The ratio of the fatty acid silver salt to water is not particularly limited, but the ratio of the fatty acid silver salt to the whole is preferably 5 to 50% by weight, and particularly preferably 10 to 35% by weight.

At the time of dispersion, it is preferable to use the above-mentioned dispersing aid, but it is preferable to use a minimum amount within a range suitable for minimizing the particle size.
0% by weight, especially in the range of 3 to 15% by weight, is preferred.

In the present invention, Ca, Mg, Ce, Al, Z
It is preferable to add a metal ion selected from n and Ba in the form of a water-soluble salt that is not a halide. Specifically, it is preferable to add in the form of nitrate or sulfate.

The Ca, Mg, Ce, Al, Zn,
The timing of addition of the metal ion selected from Ba may be determined in advance in the solution or the reaction solution of the method for preparing a silver salt of a fatty acid of the present invention, during, immediately after, before, after or after the formation of a silver salt of a fatty acid, and in preparing a coating solution. Any time, just before or after application, may be used. Preferably, it is immediately after the formation of the fatty acid silver salt before dispersion.

The addition amount is preferably from 10 ^-3 to 10 ^-1 mol, particularly from 2 × 10 ^{-3 to} 5 ×, per mol of the fatty acid silver salt.
10 ^-2 mol is preferred.

The fatty acid silver salt prepared by the method for preparing a fatty acid silver salt of the present invention is dispersed in an aqueous solvent, mixed with an aqueous solution of a photosensitive silver salt, and supplied as a coating solution for a photosensitive image forming medium. You.

The photosensitive silver halide used in the present invention is not particularly limited as a halogen composition, and silver chloride, silver chlorobromide, silver bromide, silver iodobromide, and silver iodochlorobromide can be used. . The distribution of the halogen composition in the grains may be uniform, the halogen composition may change stepwise, or may change continuously. Further, silver halide grains having a core / shell structure can be preferably used. The preferred structure is
The core has a double / five-layer structure, and more preferably has a double / four-layer structure.
Shell particles can be used. A technique for localizing silver bromide on the surface of silver chloride or silver chlorobromide grains can also be preferably used.

Methods for forming light-sensitive silver halide are well known in the art, for example, Research Disclosure No. 17029, June 1978, and US Pat. No. 3,700,458.
Can be used.Specifically, a photosensitive silver halide is prepared by adding a silver-supplying compound and a halogen-supplying compound to a gelatin or other polymer solution, and then the organic silver halide is added. A method of mixing with a silver salt is used. The grain size of the photosensitive silver halide is
For the purpose of suppressing white turbidity after image formation, it is preferably small, specifically 0.20 μm or less, more preferably 0.1 μm or less.
01 μm or more and 0.15 μm or less, more preferably 0.02 μm or more and 0.1 μm or more.
It is preferably 12 μm or less. Here, the grain size means the length of the edge of the silver halide grain when the silver halide grain is a cubic or octahedral so-called normal crystal. In the case where the silver halide grains are tabular grains, the diameter refers to a diameter when converted into a circular image having the same area as the projected area of the main surface. In the case of other than normal crystals, for example, in the case of spherical grains, rod-shaped grains, etc., it refers to the diameter of a sphere equivalent to the volume of silver halide grains.

The shape of the silver halide grains is cubic,
Octahedral, tabular particles, spherical particles, rod-like particles, potato-like particles and the like can be mentioned. In the present invention, cubic particles and tabular particles are particularly preferable. When the tabular silver halide grains are used, the average aspect ratio is preferably from 100: 1 to 2: 1, more preferably from 50: 1 to 3: 1. Further, grains having rounded corners of silver halide grains can also be preferably used. The surface index (mirror index) of the outer surface of the photosensitive silver halide grains is not particularly limited, but the spectral sensitizing efficiency when the spectral sensitizing dye is adsorbed is high. preferable.
The ratio is preferably at least 50%, more preferably at least 65%, even more preferably at least 80%. The ratio of the {100} plane of the Miller index is determined by T. Tani; J. Imaging Sci., 29, 165 (19), which utilizes the dependence of the adsorption of the sensitizing dye on the {111} plane and the {100} plane.
(1985).

The light-sensitive silver halide grains of the present invention can be prepared from Group VII or VIII (Groups 7 to 10) of the periodic table.
Of a metal or metal complex. Rhodium, rhenium, ruthenium, osmium and iridium are preferred as the metal of Group VII or VIII of the periodic table or the central metal of the metal complex. 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. The preferred content is 1 × 10 ^-9 per mole of silver.
1 × 10 ^-3 mols is preferable from the ^{molar, 1 × 10 - 8 1 ×} 10 -4 mol per mol of silver and more preferably from 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.

As the rhodium compound used in the present invention, a water-soluble rhodium compound can be used. For example, a rhodium (III) halide compound or a rhodium complex salt having a ligand such as halogen, amines, oxalato, etc., for example, hexachlororhodium (III) complex salt, pentachloroacolodium (III) complex salt, tetrachlorodia Rhodium (III) complex salt, hexabromorhodium (II
I) complex salts, hexaammine rhodium (III) complex salts, trizalatrodium (III) complex salts and the like. These rhodium compounds are used by dissolving them in water or a suitable solvent. A method generally used to stabilize a solution of the rhodium compound, that is, a hydrogen halide aqueous solution (for example, hydrochloric acid, hydrobromic acid, hydrofluoric acid) Etc.) or a method of adding an alkali halide (eg, KCl, NaCl, KBr, NaBr, etc.). Instead of using water-soluble rhodium, it is also possible to add and dissolve other silver halide grains doped with rhodium during the preparation of silver halide.

The addition amount of these rhodium compounds is preferably in the range of 1 × 10 ⁻⁸ mol to 5 × 10 ⁻⁶ mol, particularly preferably 5 × 10 ⁻⁸ mol to 1 × 10 ⁻⁶ mol per mol of silver halide. Is a mole.

These compounds can be appropriately added at the time of production of silver halide emulsion grains and at each stage before coating the emulsion.
It is preferably incorporated into silver halide grains.

Rhenium, ruthenium and osmium used in the present invention are described in JP-A-63-2042 and JP-A-1-285941.
, 2-20852, 2-20855, etc. in the form of a water-soluble complex salt. Particularly preferred is a six-coordinate complex represented by the following formula. [ML ₆ ] ^n- where M
Represents Ru, Re or Os, L represents a ligand, n represents 0, 1,
Represents 2, 3 or 4.

In this case, the counter ion is not important, and an ammonium or alkali metal ion is used.

Preferred ligands include halide ligands, cyanide ligands, cyanide ligands, nitrosyl ligands, thionitrosyl ligands and the like.
Examples of specific complexes used in the present invention are shown below, but the present invention is not limited thereto.

[ReCl ₆ ] ^3- , [ReBr ₆ ] ^3- , [ReCl ₅ (NO)] ^2- ,
_{[Re (NS) Br 5]} 2-, [Re (NO) (CN) 5] 2-, [Re (O) 2 (CN) 4] 3-,
[RuCl ₆ ] ^3- [RuCl ₄ (H ₂ O) ₂ ] ^- , [RuCl ₅ (H ₂ O)] ^2- , [RuCl ₅ (NO)] ^2- , [Ru
^{_{Br 5 (NS)] 2-,}} [Ru (CO) 3 Cl 3] 2-, [Ru (CO) Cl 5] 2- [Ru (CO) Br 5] 2-, [OsCl 6] 3-, [ OsCl ₅ (NO)] ^2- , [Os (NO)
^{_{(CN) 5] 2-, [}} Os (NS) Br 5] 2 -, [Os (O) 2 (CN) 4] 4-

The addition amount of these compounds is 1
It is preferably in the range of 1 × 10 ⁻⁹ mol to 1 × 10 ⁻⁵ mol per mol, particularly preferably 1 × 10 ⁻⁸ mol to 1 × 10 ⁻⁶ mol.

These compounds can be appropriately added at the time of production of silver halide emulsion grains and at each stage before coating the emulsion.
It is preferably incorporated into silver halide grains.

In order to add these compounds during the formation of silver halide grains and incorporate them into the silver halide grains, a powder of a metal complex or an aqueous solution dissolved together with NaCl and KCl is used. A method in which a silver halide grain is prepared by a method in which a silver salt and a halide solution are added simultaneously as a third solution when the silver salt and the halide solution are simultaneously mixed, Alternatively, there is a method in which a required amount of an aqueous solution of a metal complex is charged into a reaction vessel during particle formation. In particular, a method in which a powder or an aqueous solution dissolved together with NaCl and KCl is added to a water-soluble halide solution is preferable.

For addition to the particle surface, a required amount of an aqueous solution of a metal complex can be charged into the reaction vessel immediately after the formation of the particles, during or during physical ripening, or at the time of chemical ripening.

As the iridium compound used in the present invention, various compounds can be used. Examples thereof include hexachloroiridium, hexaammineiridium, trioxalatoiridium, hexacyanoiridium, and pentachloronitrosyliridium. These iridium compounds are used after being dissolved in water or a suitable solvent. However, a method generally used for stabilizing a solution of the iridium compound, that is, an aqueous solution of hydrogen halide (for example, hydrochloric acid, hydrobromic acid, hydrofluoric acid) is used. Etc.) or a method of adding an alkali halide (eg, KCl, NaCl, KBr, NaBr, etc.). Instead of using water-soluble iridium, it is also possible to add and dissolve another iridium-doped silver halide grain during silver halide preparation.

The silver halide grains used in the present invention may further include cobalt, iron, nickel, chromium, palladium,
It may contain metal atoms such as platinum, gold, thallium, copper and lead. For compounds of cobalt, iron, chromium, and ruthenium, hexacyano metal complexes can be preferably used. Specific examples include ferricyanate ion, ferrocyanate ion, hexacyanocobaltate ion,
Examples include, but are not limited to, hexacyanochromate ions and hexacyanoruthenate ions. The metal complex in the silver halide may be contained uniformly, may be contained in the core portion at a high concentration, or may be contained in the shell portion at a high concentration, and there is no particular limitation.

The above metal is 1 × 1 per mole of silver halide.
It is preferably from 0 ^-9 to 1 × 10 ^-4 mol. Further, in order to contain the above-mentioned metal, a metal salt in the form of a single salt, a double salt or a complex salt can be added at the time of preparing particles.

The photosensitive silver halide grains can be desalted by washing with a method known in the art such as a noodle method or a flocculation method, but in the present invention, it may or may not be desalted. .

The gold sensitizer used for sensitizing the silver halide emulsion of the present invention to gold may have a gold oxidation number of +1 or +3, and is usually used as a gold sensitizer. Gold compounds can be used. Representative examples include chloroauric acid, potassium chloroaurate, auric trichloride, potassium auric thiocyanate, potassium iodooleate, tetracyano auric acidide, ammonium aurothiocyanate, pyridyl trichlorogold and the like.

Although the amount of the gold sensitizer to be added varies depending on various conditions, the standard is 1 × 10 ⁻⁷ mol to 1 × 10 ⁻³ mol, more preferably 1 × 10 ⁻⁶ mol, per mol of silver halide. Not less than 5 × 10 ⁻⁴ mol.

The silver halide emulsion of the present invention is preferably used in combination with gold sensitization and another chemical sensitization. As other chemical sensitization methods, known methods such as a sulfur sensitization method, a selenium sensitization method, a tellurium sensitization method, and a noble metal sensitization method can be used. When used in combination with the gold sensitization method,
For example, sulfur sensitization and gold sensitization, selenium sensitization and gold sensitization, sulfur sensitization and selenium sensitization and gold sensitization, sulfur sensitization and tellurium sensitization and gold sensitization Preferred methods include sulfur sensitization, selenium sensitization, tellurium sensitization, and gold sensitization.

The sulfur sensitization preferably used in the present invention is
Usually, a sulfur sensitizer is added, and the emulsion is stirred at a high temperature of 40 ° C. or higher for a certain period of time. Known compounds can be used as the sulfur sensitizer.For example, in addition to sulfur compounds contained in gelatin, various sulfur compounds such as thiosulfates, thioureas, thiazoles, rhodanines and the like are used. be able to. Preferred sulfur compounds are thiosulfates and thiourea compounds. The addition amount of the sulfur sensitizer varies under various conditions such as the pH, temperature, and size of silver halide grains during chemical ripening.
It is 1 × 10 ⁻⁷ to 1 × 10 ⁻² mol per mol, and more preferably 1 × 10 ⁻⁵ to 1 × 10 ⁻³ mol.

As the selenium sensitizer used in the present invention, known selenium compounds can be used. That is, it is usually carried out by adding an unstable and / or non-unstable selenium compound and stirring the emulsion at a high temperature of 40 ° C. or higher for a certain time. As unstable selenium compounds, JP-B-44-15748, JP-B-43-13489, JP-A-4-25832
And the compounds described in JP-A Nos. 4-109240 and 4-324855 can be used. In particular, the general formula (V
It is preferable to use the compounds represented by III) and (IX).

The tellurium sensitizer used in the present invention is a compound which forms silver telluride which is presumed to be a sensitizing nucleus on the surface or inside of silver halide grains. The formation rate of silver telluride in a silver halide emulsion is described in JP-A-5-3132.
It can be tested by the method described in No. 84. Examples of tellurium sensitizers include diacyl tellurides, bis (oxycarbonyl) tellurides, bis (carbamoyl) tellurides, diacyl tellurides, bis (oxycarbonyl) ditellurides, bis (carbamoyl) ditellurides, P = Te Compounds having a bond, tellurocarboxylates, Te-organyltellurocarboxylates, di (poly) tellurides,
Tellurides, tellurols, telluroacetals, tellurosulfonates, compounds having a P-Te bond, Te-containing heterocycles, tellurocarbonyl compounds, inorganic tellurium compounds,
Colloidal tellurium or the like can be used. Specifically, U.S. Patent Nos. 1,623,499, 3,320,069,
No. 772,031, British Patent No. 235,211 and No. 1,121,496,
No. 1,295,462, No. 1,396,696, Canadian Patent No. 800,
No. 958, JP-A-4-204640, Japanese Patent Application No. 3-53693, JP-A-3-31515
No. 98, No. 4-129787, Journal of Chemical Society Chemical Communication (J. Chem.
Soc. Chem. Commun.), 635 (1980), ibid, 1102 (1979), i
bid, 645 (1979), Journal of Chemical Society Parkin Transaction 1 (J. Chem. Soc.
Perkin.Trans.1), 2191 (1980), edited by S. Patai,
The Chemistry of Organic Selenium
And Tellurium Campounds
Organic Serenium and Tellunium Compounds), Vol. 1 (198
6), the compounds described in Vol. 2 (1987) can be used. In particular, JP-A-5-313284 discloses general formulas (II), (III) and (I).
Compounds represented by V) are preferred.

The amount of the selenium and tellurium sensitizers used in the present invention varies depending on the silver halide grains to be used, the conditions of chemical ripening, etc., but is generally from 1 × 10 ^-8 to 1 × 10 ⁸ per mol of silver halide. ^-2 mol, preferably 1 × 10 ^-7 to 1 × 10
^Use about ^-3 moles. The conditions for chemical sensitization in the present invention are not particularly limited, but the pH is 5 to 8, the pAg is 6 to 11, preferably 7 to 10, and the temperature is 40 to 95.
° C, preferably 45-85 ° C.

In the silver halide emulsion used in the present invention, a cadmium salt, a sulfite, a lead salt, a thallium salt, and the like may be coexistent in the process of forming silver halide grains or physical ripening.

In the present invention, reduction sensitization can be used. As specific compounds of the reduction sensitization method, in addition to ascorbic acid and thiourea dioxide, for example, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds and the like can be used. . Also, when the pH of the emulsion is 7 or more or p
Reduction sensitization can be achieved by aging while keeping Ag at 8.3 or less. Further, reduction sensitization can be achieved by introducing a single addition portion of silver ion during grain formation.

A thiosulfonic acid compound may be added to the silver halide emulsion of the present invention according to the method described in EP-A-293,917.

The silver halide emulsion in the light-sensitive material used in the present invention may be only one kind, or two or more kinds (for example,
Those with different average grain sizes, different halogen compositions, different crystal habits, different chemical sensitization conditions)
You may use together.

The amount of the photosensitive silver halide used in the present invention is preferably 0.01 mol to 0.5 mol, more preferably 0.02 mol to 0.3 mol, more preferably 0.03 mol to 1 mol of the organic silver salt. It is particularly preferably at least 0.25 mol and not more than 0.25 mol.

The timing of adding the silver halide of the present invention to the coating solution for the image forming layer is preferably from 180 minutes to immediately before coating, and preferably from 60 minutes to 10 seconds before coating. Is not particularly limited as long as the effects of the present invention are sufficiently exhibited. As a specific mixing method, a method of mixing in a tank in which the average residence time calculated from the addition flow rate and the amount of liquid sent to the coater is set to a desired time, by N. Harnby, MFE Edwards, AW Nienow, translated by Koji Takahashi There is a method using a static mixer or the like described in Chapter 8 of "Liquid Mixing Technology" (published by Nikkan Kogyo Shimbun, 1989).

The photothermographic material of the present invention preferably contains a reducing agent for an organic silver salt. The reducing agent for the organic silver salt may be 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 5 to 50% based on 1 mol of silver on the surface having the image forming layer.
(Mol), more preferably 10 to 40 mol%. The layer to which the reducing agent is added may be any layer on the side having the image forming layer. When it is added to a layer other than the image forming layer, it is preferable to use a relatively large amount of 10 to 50 mol% with respect to 1 mol of silver. Further, the reducing agent may be a so-called precursor which is derivatized so as to have a function effectively only during development.

In a photothermographic material using an organic silver salt, a wide range of reducing agents are disclosed in JP-A-46-6074 and JP-A-47-1238.
47-33621, 49-46427, 49-115540, 50-14
No. 334, No. 50-36110, No. 50-147711, No. 51-32632,
No. 51-1023721, No. 51-32324, No. 51-51933, No. 52-8
4727, 55-108654, 56-146133, 57-82828
No. 57-82829, JP-A-6-3793, U.S. Pat.
No. 86, No. 3,679,426, No. 3,751,252, No. 3,751,255
Nos. 3,761,270, 3,782,949, 3,839,048,
3,928,686, 5,464,738, German patent 2321328,
It is disclosed in European Patent No. 692732 and the like. For example, phenylamide oxime, 2-thienylamide oxime and
amide oximes such as p-phenoxyphenylamide oxime; azines such as 4-hydroxy-3,5-dimethoxybenzaldehyde azine; combinations of 2,2′-bis (hydroxymethyl) propionyl-β-phenylhydrazine with ascorbic acid Combinations of such aliphatic carboxylic acid aryl hydrazides with ascorbic acid; polyhydroxybenzene, hydroxylamine, reductone and / or
Or a combination of hydrazines (e.g., hydroquinone,
Bis (ethoxyethyl) hydroxylamine, piperidinohexose reductone or a combination of formyl-4-methylphenylhydrazine); hydroxamic acids such as phenylhydroxamic acid, p-hydroxyphenylhydroxamic acid and β-alinine hydroxamic acid; Combinations of azines and sulfonamidophenols (e.g., phenothiazine and 2,6-dichloro-4-benzenesulfonamidophenol); alphas such as ethyl-α-cyano-2-methylphenyl acetate, ethyl-α-cyanophenyl acetate -Cyanophenylacetic acid derivative; 2,2'-dihydroxy-1,
1'-binaphthyl, 6,6'-dibromo-2,2'-dihydroxy-
Bis-β-naphthol as exemplified by 1,1′-binaphthyl and bis (2-hydroxy-1-naphthyl) methane; bis-β-naphthol and 1,3-dihydroxybenzene derivatives
(E.g., 2,4-dihydroxybenzophenone or 2 ',
4-pyrazolone, such as 3-methyl-1-phenyl-5-pyrazolone;
Reductones as exemplified by dimethylaminohexose reductone, anhydrodihydroaminohexose reductone and anhydrodihydropiperidone hexose reductone; 2,6-dichloro-4-benzenesulfonamidophenol and p-benzenesulfone Sulfonamidophenol reducing agents such as amidophenol; 2-phenylindane-1,3-dione; 2,2-dimethyl-7-t-butyl-
Chromans such as 6-hydroxychroman; 2,6-dimethoxy
1, such as -3,5-dicarbethoxy-1,4-dihydropyridine
4-dihydropyridine; bisphenol (eg, bis (2-
(Hydroxy-3-t-butyl-5-methylphenyl) methane, 2,2
-Bis (4-hydroxy-3-methylphenyl) propane, 4,4-
Ethylidene-bis (2-t-butyl-6-methylphenol),
1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-
Trimethylhexane and 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, etc.); ascorbic acid derivatives (eg, 1-ascorbyl palmitate, ascorbyl stearate, etc.); and aldehydes such as benzyl and biacetyl. Ketones; 3-pyrazolidones and certain indan-1,3-diones; chromanols (such as tocopherol). Particularly preferred reducing agents are bisphenol and chromanol.

The reducing agent of the present invention may be added by any method such as a solution, a powder, and a dispersion of solid fine particles. 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 contained, the optical density may be increased. Toning agents may also be advantageous in forming black silver images. The toning agent is preferably contained in an amount of 0.1 to 50 mol% per mol of silver on the surface having the image forming layer, and 0.1 to 50 mol%.
More preferably, the content is 5 to 20 mol%. Further, the toning agent may be a so-called precursor which is derivatized so as to have a function effectively only during development.

In a photothermographic material using an organic silver salt, a wide range of color toning agents are disclosed in JP-A-46-6077 and JP-A-47-10282.
Nos. 49-5019, 49-5020, 49-91215, 49-9
No. 1215, No. 50-2524, No. 50-32927, No. 50-67132,
No. 50-67641, No. 50-114217, No. 51-3223, No. 51-279
No. 23, No. 52-14788, No. 52-99813, No. 53-1020, No. 5
3-76020, 54-156524, 54-156525, 61-1836
No. 42, JP-A-4-56848, JP-B-49-10727, 54-2033
No. 3, U.S. Pat.Nos. 3,080,254, 3,446,648, 3,782,9
No. 41, No. 4,123,282, No. 4,510,236, British Patent 138079
No. 5, Belgian Patent No. 841910 and the like. Examples of toning agents are phthalimide and N-hydroxyphthalimide; succinimide, pyrazolin-5-one and quinazolinone, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and 2,4-thiazolidinedione Cyclic imides such as; naphthalimides (eg, N
-Hydroxy-1,8-naphthalimide); cobalt complexes (eg, cobalt hexamine trifluoroacetate); 3-
Mercapto-1,2,4-triazole, 2,4-dimercaptopyrimidine, 3-mercapto-4,5-diphenyl-1,2,4-triazole and 2,5-dimercapto-1,3,4-thiadiazole Illustrative mercaptans; N- (aminomethyl) aryldicarboximides, such as (N, N-dimethylaminomethyl) phthalimide and N, N- (dimethylaminomethyl)-
Naphthalene-2,3-dicarboximide); and blocked pyrazoles, isothiuronium derivatives and certain photobleaching agents (eg, 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-benzothia) Zolinylidene) -1-methylethylidene] -2-thio-2,4-oxazolidinedione; phthalazinone, phthalazinone derivative or metal salt, or 4- (1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7- Derivatives such as dimethoxyphthalazinone and 2,3-dihydro-1,4-phthalazinedione; phthalazinone and phthalic acid derivatives (for example, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic acid) Combination of anhydride such as phthalic acid); phthalazine, phthalazine derivatives or metal salts or 4- (1-naphthyl)
Derivatives such as phthalazine, 6-isopropylphthalazine, 6-tert-butylphthalazine, 6-chlorophthalazine, 5,7-dimethoxyphthalazine and 2,3-dihydrophthalazine;
Combinations of phthalazines and phthalic acid derivatives (e.g., phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride, etc.); quinazolinedione, benzoxazine or naphthoxazine derivatives; Rhodium complexes that also function in situ as sources of halide ions for silver halide formation, such as ammonium hexachlororhodate (III), rhodium bromide, rhodium nitrate and hexachlororhodium (I
II) potassium acid and the like; inorganic peroxides and persulfates, such as ammonium disulfide and hydrogen peroxide;
Benzoxazine-2 such as 3-benzoxazine-2,4-dione, 8-methyl-1,3-benzoxazine-2,4-dione and 6-nitro-1,3-benzoxazine-2,4-dione Pyrimidines and asymmetric-triazines (eg, 2,4-dihydroxypyrimidine, 2-hydroxy-4-aminopyrimidine, etc.), azauracil, and tetraazapentalene derivatives (eg, 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, 5,6
a-tetraazapentalene).

The color-toning agent of the present invention 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.

In the present invention, the organic silver salt-containing layer, which is the image forming layer, is preferably formed by coating and drying using a coating solution in which 30 wt% or more of the solvent is water. Layer binder (hereinafter `` polymer of the present invention ''
It is preferable to use a polymer latex that is soluble or dispersible in an aqueous solvent (aqueous solvent), and particularly has an equilibrium water content of 2 wt% or less at 25 ° C. and 60% RH. The most preferred form has an ionic conductivity of 2.5 mS / cm or less (preferably 0.0
(5 mS / cm or more). As such a preparation method, a method of purifying using a separation functional membrane after synthesizing a polymer may be mentioned.

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

The term “aqueous solvent” is used herein even in the case where the polymer is not thermodynamically dissolved but exists in a so-called dispersed state.

The term “equilibrium water content at 25 ° C. and 60% RH” as used in the present invention refers to the weight W1 of a polymer which is in a moisture-conditioning equilibrium in an atmosphere of 25 ° C. and 60% RH, and the weight of a polymer which is in an absolutely dry state at 25 ° C. weight
It can be expressed as follows using W0. Equilibrium water content at 25 ° C and 60% RH = {(W1-W0) / W0} x 100 (wt%) For the definition and measurement method of water content, see, for example, Polymer Engineering Course 14, Polymer Material Testing Method (Polymer (Academic Society, Jinjinshokan).

The equilibrium water content of the polymer of the present invention at 25 ° C. and 60% RH is preferably 2% by weight or less, more preferably 0.01% by weight or more and 1.5% by weight or less, more preferably 0.02% by weight or less.
It is desirable that the content be at least t% and at most 1 wt%.

The polymer of the present invention is soluble or dispersible in the above-mentioned aqueous solvent and has an equilibrium water content at 25 ° C. and 60% RH of 2 wt.
There is no particular limitation as long as it is less than%. Among these polymers, polymers that can be dispersed in an aqueous solvent are particularly preferred.

Examples of the dispersion state include a latex in which fine particles of a solid polymer are dispersed, and a dispersion in which polymer molecules are dispersed in a molecular state or in the form of micelles.

In a preferred embodiment of the present invention, acrylic resin, polyester resin, rubber-based resin (for example, SBR
Resin), a polyurethane resin, a vinyl chloride resin, a vinyl acetate resin, a vinylidene chloride resin, a hydrophobic polymer such as a polyolefin resin. 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 polymer has a number average molecular weight of 5000 to 100000, preferably 10,000 to 200,000. If the molecular weight is too small, the mechanical strength of the emulsion layer is insufficient, and if it is too large, the film-forming properties are poor, which is not preferable.

The polymer of the present invention is a polymer in which these polymers are dispersed in an aqueous dispersion medium. Here, the aqueous system refers to a dispersion medium in which 30% by weight or more of the composition is water. The dispersion state may be any state such as emulsified and dispersed, micelle dispersed, and further dispersed in a molecular state of a polymer having a hydrophilic site in a molecule, and of these, latex is particularly preferred. .

The following are specific examples of preferred polymers. In the following, the raw material monomers are used, the numerical value in parentheses is wt%, and the molecular weight is the number average molecular weight.

Latex of P-1; -MMA (70) -EA (27) -MAA (3)-(molecular weight 37000) P-2; -MMA (70) -2EHA (20) -St (5) -AA (5) -Latex (molecular weight 40000) P-3; -St (50) -Bu (47) -MAA (3) -latex (molecular weight 4500
0) P-4; -St (68) -Bu (29) -AA (3)-latex (MW 60000) P-5; -St (70) -Bu (27) -IA (3)-latex (Molecular weight 12000
0) Latex of P-6; -St (75) -Bu (24) -AA (1)-(molecular weight 10800
0) P-7; -St (60) -Bu (35) -DVB (3) -MAA (2)-latex (molecular weight 150,000) P-8; -St (70) -Bu (25) -DVB ( 2) -AA (3)-latex (molecular weight 280000) P-9; -VC (50) -MMA (20) -EA (20) -AN (5) -AA (5)-latex (molecular weight 80000) P-10; -VDC (85) -MMA (5) -EA (5) -MAA (5)-latex (molecular weight 67,000) P-11; -Et (90) -MAA (10)-latex (molecular weight) 12000)

The abbreviations of the above structures represent the following monomers.
MMA; methyl methacrylate, EA; ethyl acrylate, MAA; methacrylic acid, 2EHA; 2-ethylhexyl acrylate, St; styrene, Bu; butadiene, AA; acrylic acid, DVB; divinylbenzene, VC; vinyl chloride, AN;
Acrylonitrile, VDC; vinylidene chloride, Et; ethylene, IA; itaconic acid.

The polymers described above are commercially available, and the following polymers can be used. Examples of acrylic resin include Sebian A-4635, 46683, 4601 (all manufactured by Daicel Chemical Industries, Ltd.), Nipol Lx811, 814, 821, 820, 85
Examples of polyester resins such as 7 (all manufactured by Zeon Corporation) include FINETEX ES650, 611, 675, 850 (all manufactured by Dainippon Ink and Chemicals), WD-size, WMS (all manufactured by Eastman Chemical Co., Ltd.) HYDRA is an example of a polyurethane resin.
Examples of rubber resins such as NAP10, 20, 30, 40 (all manufactured by Dainippon Ink and Chemicals, Inc.) include LACSTAR 7310K, 3307B,
4700H, 7132C (all manufactured by Dainippon Ink and Chemicals, Inc.), Nipol Lx
Examples of vinyl chloride resins such as 416, 410, 438C, and 2507 (all manufactured by Nippon Zeon Co., Ltd.)
Examples of vinylidene chloride resin, such as L502,
Examples of olefin resins such as L513 (manufactured by Asahi Chemical Industry Co., Ltd.) include Chemipearl S120 and SA100 (Mitsui Petrochemical
And the like).

These polymers may be used alone as a polymer latex, or two or more of them may be blended if necessary.

The polymer latex used in the present invention is particularly preferably a styrene-butadiene copolymer latex. The weight ratio of the styrene monomer unit to the butadiene monomer unit in the styrene-butadiene copolymer is preferably from 40:60 to 95: 5. Also,
The proportion of the styrene monomer unit and the butadiene monomer unit in the copolymer is preferably 60 to 99% by weight. The preferred molecular weight range is the same as described above.

Styrene preferably used in the present invention
As the butadiene copolymer latex, the above-mentioned P-3
~ P-8, commercial products LACSTAR-3307B, 7132C, Nipol Lx4
16, and the like.

If necessary, a hydrophilic polymer such as gelatin, polyvinyl alcohol, methylcellulose, or hydroxypropylcellulose may be added to the organic silver salt-containing layer of the light-sensitive material of the present invention. The amount of these hydrophilic polymers added is 30 wt% or less of the total binder in the organic silver salt-containing layer,
More preferably, it is 20 wt% or less.

The organic silver salt-containing layer of the present invention is formed using a polymer latex. The amount of the binder in the organic silver salt-containing layer is such that the total binder / organic silver salt weight ratio is 1/10. 1010/1, more preferably 1/5 to 4/1.

Such an organic silver salt-containing layer is usually also a photosensitive layer (emulsion layer) containing a photosensitive silver halide, which is a photosensitive silver salt. The weight ratio of silver / silver halide is preferably in the range of 400-5, more preferably in the range of 200-10.

The total amount of the binder in the image forming layer of the present invention is 0.1.
The range is preferably ^{2 to} 30 g / m ² , more preferably 1 to 15 g / m ² . A crosslinking agent for crosslinking, a surfactant for improving coating properties, and the like may be added to the image forming layer of the invention.

In the present invention, the solvent of the coating solution for the organic silver salt-containing layer of the light-sensitive material (herein, the solvent and the dispersion medium are collectively referred to as a solvent for simplicity) is an aqueous solvent containing 30% by weight or more of water. As a component other than water, any water-miscible organic solvent such as methyl alcohol, ethyl alcohol, isopropyl alcohol, methyl cellosolve, ethyl cellosolve, dimethylformamide, and ethyl acetate may be used. The water content of the solvent in the coating solution is preferably at least 50 wt%, more preferably at least 70 wt%. Examples of preferred solvent composition include water, water / methyl alcohol = 90/10, water / methyl alcohol = 70/30, water / methyl alcohol / dimethylformamide = 80/15/5, water / methyl alcohol / Ethyl cell solve = 8
5/10/5, water / methyl alcohol / isopropyl alcohol = 85/10/5 (numerical value is wt%).

As the sensitizing dye in the present invention, any dye can be used as long as it can spectrally sensitize the silver halide grains in a desired wavelength region when adsorbed on the silver halide grains. As the sensitizing dye, a cyanine dye, a merocyanine dye, a complex cyanine dye, a complex merocyanine dye, a holopolar cyanine dye, a styryl dye, a hemicyanine dye, an oxonol dye, a hemioxonol dye, and the like can be used. Useful sensitizing dyes for use in the present invention include, for example, RESEARCH DISCLOSURE Item 17
Item 643IV-A (p.23, December 1978), Item 1831X (August 1979)
p.437) or in the literature cited. In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of the light source of various laser imagers, scanners, imagesetters and plate making cameras can be advantageously selected.

Examples of spectral sensitization to red light include He-Ne
For a so-called red light source such as a laser, a red semiconductor laser or an LED, a compound of I-1 to I-38 described in JP-A-54-18726, and a compound of I-1 described in JP-A-6-75322. I-3
5 and the compounds I-1 to I- described in JP-A-7-287338.
34 compounds, dyes 1 to 20 described in JP-B-55-39818,
The compounds I-1 to I-37 described in JP-A-62-284343 and the compounds I-1 to I-34 described in JP-A-7-287338 are advantageously selected.

For a semiconductor laser light source in the wavelength range of 750 to 1400 nm, various known dyes including cyanine, merocyanine, styryl, hemicyanine, oxonol, hemioxonol and xanthene dyes are spectrally advantageously sensitized. Can be done. Useful cyanine dyes are, for example, cyanine dyes having basic nuclei such as thiazoline nuclei, oxazoline nuclei, pyrroline nuclei, pyridine nuclei, oxazole nuclei, thiazole nuclei, selenazole nuclei and imidazole nuclei. Preferred useful merocyanine dyes include, in addition to the above basic nuclei, acidic nuclei such as thiohydantoin nucleus, rhodanine nucleus, oxazolidinedione nucleus, thiazolinedione nucleus, barbituric acid nucleus, thiazolinone nucleus, malononitrile nucleus and pyrazolone nucleus. Including. Among the above cyanine and merocyanine dyes, those having an imino group or a carboxyl group are particularly effective. For example, U.S. Patent 3,761,279,
3,719,495 and 3,877,943, British Patent 1,466,201
No. 1,469,117, No. 1,422,057, Tokuhei 3-10391
No. 6-52387, JP-A-5-341432, 6-94781,
It may be appropriately selected from known dyes as described in JP-A-6-301141.

Particularly preferred as the structure of the dye used in the present invention is a cyanine dye having a thioether bond-containing substituent (for example, see JP-A-62-58239 and JP-A-3-13863).
No.8, No.3-138642, No.4-255840, No.5-72659, No.5-
72661, 6-222491, 2-230506, 6-258757
No., 6-317868, 6-324425, Tokuyohei 7-500926,
Dyes described in U.S. Pat.No. 5,541,054), dyes having a carboxylic acid group (for example, JP-A-3-163440, 6-301
No. 141, dyes described in U.S. Pat.No. 5,441,899), merocyanine dyes, polynuclear merocyanine dyes and polynuclear cyanine dyes (JP-A-47-6329, JP-A-49-105524, JP-A-51-127719,
No. 52-80829, No. 54-61517, No. 59-214846, No. 60-67
No. 50, 63-159841, JP-A-6-35109, 6-59381
No., 77-146537, 77-146537, Tokuyohei 55-50111,
Dyes described in British Patent 1,467,638 and US Patent 5,281,515).

Further, dyes described in Example 5 of US Pat. Nos. 5,510,236 and 3,871,887 as dyes forming a J-band,
JP-A-2-96131 and JP-A-59-48753 are disclosed and can be preferably used in the present invention.

These sensitizing dyes may be used alone.
Two or more kinds may be used in combination. Combinations of sensitizing dyes are often used, especially for supersensitization. Along with the sensitizing dye, the emulsion may contain a dye which does not itself have a spectral sensitizing effect or a substance which does not substantially absorb visible light and exhibits supersensitization. Useful sensitizing dyes, combinations of dyes exhibiting supersensitization and substances exhibiting supersensitization are
Research Disclosure Volume 176, 17643 (December 1978) No. 23
Section IV of Page IV, or JP-B-49-25500, 43-43933,
These are described in JP-A-59-19032 and JP-A-59-192242.

The sensitizing dyes may be added to the silver halide emulsion by dispersing them directly in the emulsion or by adding water, methanol, ethanol, propanol, acetone, methylcellosolve, 2,2, 3,3-tetrafluoropropanol, 2,2,2-trifluoroethanol, 3-methoxy
It may be added to the emulsion by dissolving it in a solvent such as 1-propanol, 3-methoxy-1-butanol, 1-methoxy-2-propanol, N, N-dimethylformamide, alone or in a mixed solvent.

As disclosed in US Pat. No. 3,469,987, a dye is dissolved in a volatile organic solvent, this solution is dispersed in water or a hydrophilic colloid, and this dispersion is dispersed in an emulsion. Method of adding to Japanese Patent Publication No. 44-23389,
As disclosed in JP-A-44-27555 and JP-A-57-22091, a dye is dissolved in an acid and this solution is added to the emulsion, or an acid or base is added to the emulsion as an aqueous solution in the presence of an acid or base. A method of adding an aqueous solution or a colloidal dispersion in the presence of a surfactant to an emulsion as disclosed in U.S. Patent Nos. 3,822,135 and 4,006,025, JP-A-51-746, a method in which a dye is directly dispersed in a hydrophilic colloid and the dispersion is added to an emulsion as disclosed in JP-A-51-746.
As disclosed in JP-A No. 24, a method of dissolving a dye using a compound that causes a red shift and adding this solution to an emulsion can also be used. Also, ultrasonic waves can be used for dissolution.

The sensitizing dye used in the present invention may be added to the silver halide emulsion of the present invention at any stage of the emulsion preparation which has been found to be useful. For example, U.S. Patents 2,735,766 and 3,628,960,
4,183,756, 4,225,666, JP-A-58-184142,
As disclosed in the specification of JP-A-60-196749 and the like, the timing before silver halide grain forming step and / or desalting, during and / or after desalting and before the start of chemical ripening. As disclosed in the specification such as JP-A-58-113920, any time immediately before chemical ripening or during the process, after chemical ripening, and before coating the emulsion before coating It may be added at the time and in the process.
Further, as disclosed in the specification of U.S. Pat. No. 4,225,666, JP-A-58-7629, etc., the same compound may be used alone or in combination with a compound having a different structure, for example, during the particle forming step. The compound may be divided and added during the ripening step or after the completion of the chemical ripening, or may be added separately before or during the chemical ripening or after the completion of the chemical ripening. May be added.

The amount of the sensitizing dye used in the present invention may be a desired amount in accordance with the performance such as sensitivity and fog.
The amount is preferably from 10 ^-6 to 1 mol, more preferably from 10 ^-4 to 10 ^-1 mol, per mol of silver halide in the photosensitive layer.

The silver halide emulsion according to the invention or /
And the organic silver salts can be further protected against the formation of additional fog by antifoggants, stabilizers and stabilizer precursors, and can be stabilized against reduced sensitivity during storage in inventory. Suitable antifoggants, stabilizers and stabilizer precursors that can be used alone or in combination are the thiazonium salts described in U.S. Pat.Nos. 2,131,038 and 2,694,716; U.S. Pat.Nos. 2,886,437 and 2,444,605. Azaindene, U.S. Pat.
8,663 mercury salt, U.S. Pat.No. 3,287,135 urazole, U.S. Pat.No. 3,235,652 sulfocatechol, British Patent 623,448 Oxime,
Nitrone, nitroindazole, U.S. Patent No. 2,839,405
No. 3,220,839, thiuronium salts, and U.S. Pat.Nos. 2,566,263 and 2,597,915, palladium, platinum and gold salts, U.S. Pat.Nos. 4,108,665 and 4,442,202 No. 4,128,557
Nos. 4,137,079 and 4,138,365 and 4,
No. 4,59,350 and U.S. Pat.
And the phosphorus compounds described in No. 1,985.

The antifoggant preferably used in the present invention is an organic halide, for example, as described in JP-A-50-119624.
No. 50-120328, No. 51-121332, No. 54-58022, No.
56-70543, 56-99335, 59-90842, 61-12964
No. 2, 62-129845, JP-A-6-208191, 7-5621,
Nos. 7-2781, 8-15809, U.S. Pat.
Compounds such as those disclosed in US Pat.

The antifoggant of the present invention 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.

Although not required to practice the present invention,
It may be advantageous to add a mercury (II) salt as an antifoggant to the emulsion layer. Preferred mercury (II) salts for this purpose are
Mercury acetate and mercury bromide. The amount of mercury used in the present invention is preferably 1 × 10 ⁻⁹ mol to 1 × 10 ⁻³ mol, more preferably 1 × 10 ⁻³ mol, per mol of the coated silver.
The range is from ^-9 mol to 1 × 10 ^-4 mol.

The photothermographic material of the present invention may contain benzoic acids for the purpose of increasing the sensitivity and preventing fog. The benzoic acids of the present invention may be any benzoic acid derivative, but examples of preferred structures include those described in U.S. Pat.
No. 9, No. 4, 152, 160, Japanese Patent Application No. 8-151242, No. 8-151241
And the compounds described in JP-A-8-98051 and the like. The benzoic acid of the present invention may be added to any part of the light-sensitive material, but it is preferable to add the benzoic acid to the layer having the photosensitive layer (image forming layer), and to add it to the organic silver salt-containing layer. More preferably, The benzoic acid of the present invention may be added at any time during the preparation of the coating solution, and when it is added to the organic silver salt-containing layer, it may be added at any time from the preparation of the organic silver salt to the preparation of the coating solution. It is preferable after salt preparation and immediately before application. The benzoic acid of the present invention 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 of the present invention may be added in any amount, but is preferably from 1 × 10 ⁻⁶ mol to 2 mol, more preferably from 1 × 10 ⁻³ mol to 0.5 mol, per mol of silver.

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

When a mercapto compound is used in the present invention, it may be of any structure, but may be any of Ar-SM, Ar-SSA
Those represented by r are preferred. In the formula, M is a hydrogen atom or an alkali metal atom, and Ar is an aromatic ring group or a condensed aromatic ring group having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms. Preferably, the heteroaromatic ring in these groups 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 includes, for example, halogens (e.g., Br and Cl), hydroxy, amino, carboxy,
Alkyl (e.g. one or more carbon atoms, preferably 1-4
Having one carbon atom) and alkoxy (e.g.,
One having at least one carbon atom, preferably having 1 to 4 carbon atoms). Examples of the mercapto-substituted heteroaromatic compound include 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole,
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-hydroxysil-2-mercaptopyrimidine, 2-mercaptopyrimidine, 4,6-diamino-2-mercaptopyrimidine, 2-mercapto-4-methyl Pyrimidine hydrochloride, 3-mercapto-5-phenyl-1,2,4-triazole,
Examples include 2-mercapto-4-phenyloxazole, but the present invention is not limited thereto.

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

In the image forming layer (photosensitive layer) in the present invention, a polyhydric alcohol (for example, glycerin and diol of the type described in US Pat. No. 2,960,404) as a plasticizer and a lubricant, and US Pat. No. 2,588,765 are used. And fatty acids or esters described in US Pat. No. 3,121,060 and silicone resins described in British Patent No. 955,061.

In the present invention, a super-high contrast agent can be used for forming a super-high contrast image. For example, U.S. Patent No. 5,464,73
No. 8, No. 5,496,695, No. 6,512,411, No. 5,536,622,
Japanese Patent Application Nos. Hei 7-228627, Hei 8-215822, Hei 8-130842
Nos. 8-148113, 8-156378, 8-148111, 8-
The hydrazine derivative described in 148116, the compound having a quaternary nitrogen atom described in Japanese Patent Application No. 8-83566, and the acrylonitrile compound described in US Pat. No. 5,545,515 can be used. Specific examples of the compound include compounds 1 to 10 and 5,49 of the aforementioned U.S. Patent No. 5,464,738.
H-1 to H-28 of 6,695, I-1 to I-8 of Japanese Patent Application No. 8-215822
6, H-1 to H-62 of 8-130842, 1-1 to 1-2 of 8-148113
1, 1 to 50 of 8-148111, 1 to 40 of 8-148116, 8 to 8
No. 3,566, P-1 to P-26, and T-1 to T-18, U.S. Pat.
No. 5,515, CN-1 to CN-13 and the like.

Further, the present invention provides a method for forming a super-high contrast image.
A high contrast accelerator can be used in combination with the above-mentioned super-high contrast agent. For example, amine compounds described in U.S. Pat.No. 5,545,505, specifically AM-1 to AM-5, hydroxamic acids described in 5,545,507, specifically HA-1 to HA-11, and the like.
Acrylonitrile described in 5,545,507, specifically C
Hydrazine compounds described in N-1 to CN-13 and 5,558,983, specifically CA-1 to CA-6, onium salts described in Japanese Patent Application No. 8-132836, specifically A-1 to A-42, B-1 to
B-27, C-1 to C-14 and the like can be used.

The synthesis method, addition method, addition amount and the like of these super-high contrast agents and high-contrast accelerators can be carried out as described in each of the cited patents.

The photothermographic material according to the invention may be provided with a surface protective layer for the purpose of preventing adhesion of the image forming layer.

The binder for the surface protective layer of the present invention may be any polymer, but preferably contains a polymer having a carboxylic acid residue in an amount of 100 mg / m ^{2 to} 5 g / m ² . Examples of the polymer having a carboxyl residue include natural polymers (gelatin, alginic acid, etc.), modified natural polymers (carboxymethylcellulose, phthalated gelatin, etc.), synthetic polymers (polymethacrylate, polyacrylate, polyalkyl methacrylate / acrylate). Copolymer, polystyrene / polymethacrylate copolymer, etc.). The carboxy residue content of such a polymer is preferably from 1 × 10 ⁻² mol to 1.4 mol per 100 g of the polymer. Further, the carboxylic acid residue may form a salt with an alkali metal ion, an alkaline earth metal ion, an organic cation, or the like.

As the surface protective layer of the present invention, any anti-adhesion material may be used. Examples of anti-adhesion materials include waxes, silica particles, styrene-containing elastomeric block copolymers (e.g., styrene-butadiene-
Styrene, styrene-isoprene-styrene), cellulose acetate, cellulose acetate butyrate, cellulose propionate, and mixtures thereof. Further, a crosslinking agent for crosslinking and a surfactant for improving coating properties may be added to the surface protective layer.

In the image forming layer or the protective layer of the image forming layer in the present invention, US Pat. Nos. 3,253,921 and 2,27
Light absorbing substances and filter dyes as described in 4,782, 2,527,583 and 2,956,879 can be used. Also, for example, U.S. Pat.
The dye can be mordanted as described in US Pat. As the amount of filter dye used, the absorbance at the exposure wavelength is 0.
It is preferably from 1 to 3.0, and particularly preferably from 0.2 to 1.5.

The image-forming layer or the protective layer of the image-forming layer according to the present invention may comprise a matting agent such as starch, titanium dioxide, zinc oxide, silica, of the type described in US Pat. Nos. 2,992,101 and 2,701,245. Polymer beads, including beads, can be included. The matt degree of the emulsion surface may be any value as long as stardust failure does not occur, but the Beck smoothness is preferably 50 seconds or more and 10,000 seconds or less, and particularly preferably 80 seconds or more and 10,000 seconds or less.

The preparation temperature of the image forming layer coating solution of the present invention is 30.
It is preferable that the temperature is not less than 65 ° C and not more than 35 ° C.
It is not less than 60 ° C (preferably 55 ° C or less). In addition, the temperature of the image forming layer coating solution immediately after the addition of the polymer latex
It is preferable that the temperature is maintained at 30 ° C or higher and 65 ° C or lower. Also,
It is preferable that the reducing agent and the organic silver salt are mixed before the addition of the polymer latex.

The fluid containing an organic silver salt or the coating solution for the image forming layer in the present invention is preferably a so-called thixotropic fluid. The thixotropic property refers to a property in which the viscosity decreases as the shear rate increases. Although any apparatus may be used for the viscosity measurement of the present invention, an RFS fluid spectrometer manufactured by Rheometrics Far East Co., Ltd. is preferably used and is measured at 25 ° C. Here, the viscosity of the organic silver salt-containing fluid or the image forming layer coating solution in the present invention at a shear rate of 0.1 S ^-1 is preferably 400 mPas or more and 100,000 mPas or less, more preferably 50 mPas or less.
0 mPa · s or more and 20,000 mPa · s or less. Also, the shear rate 1
In 000S- ¹ , the pressure is preferably from 1 mPa · s to 200 mPa · s, more preferably from 5 mPa · s to 80 mPa · s.

Various systems expressing thixotropy are known, and are described in “Lecture / Rheology”, edited by Polymer Publishing Association, Muroi,
It is described in Morino co-authored "Polymer Latex" (published by the Society of Polymer Publishing). In order for a fluid to exhibit thixotropic properties, it is necessary to contain a large amount of solid fine particles.
In order to enhance the thixotropic property, it is effective to include a thickened linear polymer, to increase the aspect ratio of the contained solid fine particles in an anisotropic shape, to use an alkali thickener, and to use a surfactant.

The heat-developable photographic emulsion of the present invention comprises one or more layers on a support. One layer construction must include optional additional materials such as organic silver salts, silver halides, developers and binders, and toning agents, coating aids and other auxiliaries. The two-layer configuration is the first
It must contain the organic silver salt and silver halide in the emulsion layer (usually the layer adjacent to the support) and some other components in the second or both layers. However, a two-layer construction comprising a single emulsion layer containing all components and a protective topcoat is also contemplated. The construction of a multicolor photothermographic material may include a combination of these two layers for each color, and may include all components in a single layer as described in U.S. Pat.No. 4,708,928. Is also good. In the case of a multi-dye, multi-color photothermographic material, each emulsion layer is generally, as described in U.S. Pat.No. 4,460,681,
By using a functional or non-functional barrier layer between each emulsion layer (photosensitive layer), it is kept distinct from each other.

Various dyes and pigments can be used in the photosensitive layer of the present invention from the viewpoint of improving color tone and preventing irradiation. Dyes and pigments used in the photosensitive layer of the present invention may be any, for example, pigments and dyes described in the color index, specifically, pyrazoloazole dye, anthraquinone dye, azo dye, azomethine dye,
Organic dyes such as oxonol dyes, carbocyanine dyes, styryl dyes, triphenylmethane dyes, indoaniline dyes and indophenol dyes, azo pigments, polycyclic pigments (phthalocyanine pigments, anthraquinone pigments, etc.), dyeing lake pigments, Organic pigments including azine pigments, inorganic pigments and the like can be mentioned. Preferred dyes used in the present invention include anthraquinone dyes (e.g., compounds 1 to 9 described in JP-A-5-341441, compounds 3-6 to 18 and 3-23 to 38 described in JP-A-5-165147), azomethine Dyes (e.g., compounds 17 to 47 described in JP-A-5-341441), indoaniline dyes (e.g., compound 1 described in JP-A-5-289227)
1 to 19, compound 47 described in JP-A-5-341441, JP-A-5-165
No. 147 described compounds 2-10 to 11) and azo dyes (compounds 10 to 16 described in JP-A-5-341441) are preferred as anthraquinone-based indanthrone pigments (CI Pi
gment Blue 60), phthalocyanine pigments (CIPigment
Copper phthalocyanine such as Blue 15, CI Pigment Blue 16
Metal-free phthalocyanine, etc.), dyed lake pigment based triarylcarbonyl pigments, indigo, inorganic pigments
(Ultra blue, cobalt blue, etc.). As a method for adding these dyes and pigments, any method such as a solution, an emulsion, a solid fine particle dispersion, and a state in which the dye or pigment is mordanted with a polymer mordant may be used. The amount of these compounds is determined by absorption of the purpose, generally the photosensitive material 1 m ² per 1μg least 1
It is preferably used in the range of g or less. Further, a dioxane-based pigment, a quinacridone-based pigment, a diketopyrrolopyrrole-based pigment, or the like may be used in combination for adjusting redness.

In the present invention, the antihalation layer can be provided on the side farther from the light source than the photosensitive layer. The antihalation layer preferably has a maximum absorption in a desired wavelength range of 0.3 or more and 2 or less, more preferably an absorption of an exposure wavelength of 0.5 or more and 2 or less, and an absorption in a visible region after processing of 0.001 or more. It is preferably less than 0.5, and more preferably a layer having an optical density of 0.001 or more and less than 0.3.

When antihalation dyes are used in the present invention, these dyes have the desired absorption in the wavelength range, have a sufficiently low absorption in the visible region after treatment, and have the desired absorbance spectrum of the antihalation layer. Any compound can be used as long as it is possible. For example, the following are disclosed, but the present invention is not limited thereto. As a single dye, JP-A-59-56458, JP-A-Hei 2-
216140, 7-13295, 711432, U.S. Patent 5,380,
No. 635, JP-A-2-68539, page 13, lower left column, line 1 to page 14, lower left column, line 9, and JP-A-3-24539, page 14, lower left column, page 16, lower right column The dyes that can be decolorized by the treatment include JP-A-52-139136, JP-A-53-132334, and
56-501480, 57-16060, 57-68831, 57-1018
No. 35, 59-182436, JP-A-7-36145, 7-199409
No., JP-B-48-33692, JP-B-50-16648, JP-B2-41734
Nos., U.S. Pat.Nos. 4,088,497, 4,283,487, 4,548,89
No. 6 and 5,187,049.

The photothermographic material of the present invention is a so-called single-sided photosensitive material having at least one photosensitive layer containing a silver halide emulsion on one side of a support and a back layer on the other side. Preferably, there is.

In the present invention, a matting agent may be added to the single-sided photosensitive material in order to improve transportability. The matting agent is generally fine particles of an organic or inorganic compound insoluble in water. Any matting agent can be used, for example, U.S. Patent Nos. 1,939,213, 2,701,245, and 2,322,037.
No. 3,262,782, No. 3,539,344, No. 3,767,448, etc.
2,192,241, 3,257,206, 3,370,951, 3,52
Inorganic matting agents well-known in the art, such as inorganic matting agents described in the respective specifications such as 3,022 and 3,769,020, can be used. For example, specifically, examples of organic compounds that can be used as a matting agent include, as examples of water-dispersible vinyl polymers, polymethyl acrylate, polymethyl methacrylate, polyacrylonitrile, acrylonitrile-α-methylstyrene copolymer, and polystyrene. , Styrene-divinylbenzene copolymer, polyvinyl acetate, polyethylene carbonate, polytetrafluoroethylene, etc., examples of cellulose derivatives such as methylcellulose,
Examples of starch derivatives such as cellulose acetate, cellulose acetate propionate, carboxy starch, carboxynitrophenyl starch, urea-formaldehyde-
Gelatin hardened with a known hardener such as a starch reactant and hardened gelatin obtained by coacervate hardening to form fine capsule hollow particles can be preferably used. As examples of the inorganic compound, silicon dioxide, titanium dioxide, magnesium dioxide, aluminum oxide, barium sulfate, calcium carbonate, silver chloride desensitized by a known method, silver bromide, glass, and diatomaceous earth can be preferably used. The above matting agents can be used by mixing different types of substances as necessary. The size and shape of the matting agent are not particularly limited, and those having an arbitrary particle size can be used. In practicing the present invention, it is preferable to use one having a particle size of 0.1 μm to 30 μm. Further, the particle size distribution of the matting agent may be narrow or wide. On the other hand, since the matting agent greatly affects the haze and surface gloss of the light-sensitive material, the particle size, shape, and particle size distribution can be changed as necessary during the preparation of the matting agent or by mixing a plurality of matting agents. preferable.

In the present invention, the matte degree of the back layer is such that the Bekk smoothness is preferably 1200 seconds or less and 10 seconds or more, more preferably 700 seconds or less and 50 seconds or more.

In the present invention, the matting agent is preferably contained in the outermost surface layer of the light-sensitive material, a layer functioning as the outermost surface layer, or a layer close to the outer surface. It is preferable to be contained.

In the present invention, suitable binders for the back layer are transparent or translucent, generally colorless, and natural polymer synthetic resins, polymers and copolymers, and other film-forming media such as: gelatin, gum arabic, poly (vinyl) (Alcohol), hydroxyethylcellulose, cellulose acetate, cellulose acetate butyrate, poly (vinylpyrrolidone), casein, starch, poly (acrylic acid), poly (methylmethacrylic acid), poly (vinyl chloride), poly (methacrylic acid), copoly (Styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinylacetal) s (e.g., poly (vinylformal) and poly (vinylformal))
(Vinyl butyral)), poly (ester) s, poly (urethanes), phenoxy resin, poly (vinylidene chloride), poly (vinylidene chloride)
(Epoxides), poly (carbonates), poly (vinyl acetate), cellulose esters, and poly (amides). The binder may be coated from water or an organic solvent or emulsion.

In the present invention, the back layer preferably has a maximum absorption of 0.3 or more and 2 or less in a desired wavelength range.
More preferably absorption is 0.5 or more and 2 or less, and the absorption in the visible region after the treatment is preferably 0.001 or more and less than 0.5, and more preferably a layer having an optical density of 0.001 or more and less than 0.3. . Examples of the antihalation dye used in the back layer are the same as those of the antihalation layer described above.

US Pat. Nos. 4,460,681 and 4,374,9
Backside resistive heating layer as shown in No. 21
stive heating layer) can also be used in a photosensitive heat developed photographic image system.

A hardener may be used for each layer such as the image forming layer (photosensitive layer), the protective layer and the back layer of the present invention. Examples of hardeners include “THE THEORY OF THE PHOTO” by THJames.
GRAPHIC PROCESS FOURTH EDITION ”(Macmillan Publish
ing Co., Inc., published in 1977) There are various methods described on pages 77 to 87, polyvalent metal ions described on page 78 of the same book, U.S. Pat.No.4,281,060, polyisocyanates such as JP-A-6-208193, etc. , Epoxy compounds such as US Pat. No. 4,791,042, and vinyl sulfone compounds such as JP-A-62-89048 are preferably used.

The hardener is added as a solution. The time of adding this solution to the coating solution for the protective layer is from 180 minutes to immediately before coating, preferably from 60 minutes to 10 seconds before coating. The mixing conditions are not particularly limited as long as the effects of the present invention are sufficiently exhibited. As a specific mixing method, a method of mixing in a tank in which the average residence time calculated from the addition flow rate and the amount of liquid sent to the coater is set to a desired time, by N. Harnby, MFE Edwards, AW Nienow, translated by Koji Takahashi There is a method using a static mixer or the like described in Chapter 8 of "Liquid Mixing Technology" (published by Nikkan Kogyo Shimbun, 1989).

In the present invention, a surfactant may be used for the purpose of improving coating properties and charging. As the surfactant, any surfactant such as nonionic, anionic, cationic, and fluorine can be used as appropriate. Specifically,
No. 62-170950, Fluoropolymer surfactants described in U.S. Pat.No. 5,380,644, JP-A-60-244945, JP-A-63-18
8135 No. fluorinated surfactants described in U.S. Pat.
No. 5,965, and the like, and polysiloxy acid-based surfactants described in JP-A-6-301140 and the like, and polyalkylene oxide and anionic surfactants.

Examples of the solvent used in the present invention include a new edition solvent pocket book (Ohm Co., 1994), but the present invention is not limited thereto. The solvent used in the present invention has a boiling point of 40 ° C or more and 180 ° C or more.
C. or lower is preferred.

Examples of the solvent of the present invention include hexane, cyclohexane, toluene, methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, ethyl acetate, 1,1,1-trichloroethane, tetrahydrofuran,
Triethylamine, thiophene, trifluoroethanol, perfluoropentane, xylene, n-butanol,
Phenol, methyl isobutyl ketone, cyclohexanone, butyl acetate, diethyl carbonate, chlorobenzene, dibutyl ether, anisole, ethylene glycol diethyl ether, N, N-dimethylformamide, morpholine,
Examples include propane sultone, perfluorotributylamine, and water.

The heat-developable photographic emulsion of the present invention can be coated on various supports. Typical supports are polyester film, primed polyester film, poly (ethylene terephthalate) film (PET)
Film), polyethylene naphthalate film, cellulose nitrate film, cellulose ester film, poly (vinyl acetal) film, polycarbonate film and related or resinous materials, as well as glass, paper, metal and the like. Flexible substrates, especially barita and / or partially acetylated α-olefin polymers, especially α-C2-C10 α-olefins such as polyethylene, polypropylene, ethylene-butene copolymers.
A paper support coated with an olefin polymer,
Typically used. Such a support may be transparent or opaque, but is preferably transparent.

The light-sensitive material of the present invention comprises an antistatic or conductive layer, for example, a soluble salt (eg, chloride, nitrate, etc.), a vapor-deposited metal layer, US Pat. Nos. 2,861,056 and
It may have a layer containing an ionic polymer as described in US Pat. No. 3,206,312 or an insoluble inorganic salt as described in US Pat. No. 3,428,451.

A method for obtaining a color image using the photothermographic material of the present invention is described in JP-A-7-13295, page 10, left column 4
There is a method described from the third line to the 11th left column, 40th line. Also, as a stabilizer for color dye images, UK Patent No. 1,326,889
No. 3,432,300, U.S. Pat.No. 3,698,909, U.S. Pat.
Nos. 574,627, 3,573,050, 3,764,337 and 4,042,394.

The photothermographic material of the present invention may be applied by any method. Specifically, extrusion coating, slide coating, curtain coating, dip coating, knife coating,
Various coating operations are used, including flow coating or extrusion coating using a hopper of the type described in U.S. Pat. No. 2,681,294, and are described by Stephen F. Kistl.
er, "LIQUID FILM COATING" by Peter M. Schweizer (C
Extrusion coating or slide coating described on pages 399 to 536, published by HAPMAN & HALL (1997) is preferably used, and particularly preferably slide coating is used. An example of the shape of the slide coater used for slide coating is shown in Figure 11 on page 427 of the same book.
in b.1. Also, if desired, the method described on page 399 to 536 of the same book, U.S. Pat.No. 2,761,791 and British Patent 837,0
Two or more layers can be coated simultaneously by the method described in No. 95.

Additional layers in the photothermographic material of the present invention, such as a dye-receiving layer for receiving a moving dye image, an opaque layer if reflective printing is desired, a protective topcoat layer and photothermographic techniques It may include a known primer layer and the like. The light-sensitive material of the present invention is preferably capable of forming an image with only one light-sensitive material, and it is preferable that a functional layer necessary for image formation such as an image receiving layer does not become another light-sensitive material.

The light-sensitive material of the present invention may be developed by any method, but is usually developed by raising the temperature of the light-sensitive material exposed imagewise. The preferred development temperature is 80 to
The temperature is 250 ° C, more preferably 100 to 140 ° C. The development time is preferably from 1 to 180 seconds, more preferably from 10 to 90 seconds.

The light-sensitive material of the present invention may be exposed by any method, but a laser beam is preferred as an exposure light source.
As the laser beam according to the present invention, gas laser, YAG
Lasers, dye lasers, semiconductor lasers and the like are preferred. Further, a semiconductor laser and a second harmonic generation element can be used.

The light-sensitive material of the present invention has a low haze at the time of exposure and tends to generate interference fringes. Examples of this interference fringe prevention technology include a technology for obliquely entering a laser beam into a photosensitive material as disclosed in JP-A-5-113548 and a multi-mode laser disclosed in WO95 / 31754 and the like. There is known a method of utilizing these techniques, and it is preferable to use these techniques.

To expose the light-sensitive material of the present invention, SPIE vo
l.169 Laser Printing 116-128 (1979), JP-A-4-5104
No. 3, WO95 / 31754, etc., it is preferable to expose the laser beams so that they overlap each other so that the scanning lines are not visible.

[0180]

The present invention will be specifically described below with reference to examples. Example 1 << Preparation of PET support >> Terephthalic acid and ethylene glycol
And PET having an intrinsic viscosity IV = 0.66 (measured in phenol / tetrachloroethane = 6/4 (weight ratio) at 25 ° C.) using a conventional method. After pelletizing and drying at 130 ° C for 4 hours, 30
After being melted at 0 ° C., it was extruded from a T-die and quenched to prepare an unstretched film having a thickness of 175 μm after heat setting.

This was longitudinally stretched 3.3 times using rolls having different peripheral speeds, and then horizontally stretched 4.5 times using a tenter. The temperatures at this time were 110 ° C. and 130 ° C., respectively.
After that, it was heat-set at 240 ° C. for 20 seconds and relaxed 4% in the lateral direction at the same temperature. Then, after slitting the chuck portion of the tenter, knurling was performed on both ends and wound at 4 kg / cm ² to obtain a roll having a thickness of 175 μm.

<< Surface Corona Treatment >> Using a solid state corona treatment machine 6KVA model manufactured by Pillar Co., both surfaces of the support were treated at room temperature at 20 m / min. From the current and voltage readings at this time, it was found that the support was treated at 0.375 kV · A · min / m ² . At this time, the processing frequency was 9.6 kHz, and the gap clearance between the electrode and the dielectric roll was 1.6 mm.

<< Preparation of Undercoating Support >> (Preparation of Undercoating Coating Solution A) Polystyrene fine particles (average particle size: 0.2 μm) were added to 200 ml of an aqueous dispersion of polyester copolymer Pesresin A-515GB (30 wt%, manufactured by Takamatsu Oil & Fats Co., Ltd.). ) 1g, surfactant
20 ml of 1 (1 wt%) was added, and distilled water was added thereto to make 1000 ml, thereby obtaining an undercoat coating liquid A.

(Preparation of Undercoating Coating Solution B) 200 ml of an aqueous dispersion of a styrene-butadiene copolymer (styrene / butadiene / itaconic acid = 47/50/3 (weight ratio), concentration 30 wt%) in 680 ml of distilled water,
Add 0.1 g of polystyrene fine particles (average particle size 2.5 μm),
Further, distilled water was added to make 1000 ml, thereby obtaining an undercoating coating solution B.

(Preparation of Undercoating Coating Solution C) Inert Gelatin 1
0 g was dissolved in 500 ml of distilled water, and 40 g of an aqueous dispersion (40 wt%) of tin oxide-antimony oxide composite fine particles described in JP-A-61-20033 was added thereto, and distilled water was added thereto. Ten
Undercoating solution C was made up to 00 ml.

(Preparation of Undercoat Support) After the above-mentioned corona discharge treatment, the undercoat coating solution A was applied using a bar coater so that the wet coating amount was 5 ml / m ² , and dried at 180 ° C. for 5 minutes. The dry film thickness was about 0.3 μm. Then this back
After applying the corona discharge treatment to the (back side), the undercoat coating liquid
B is applied with a bar coater so that the wet coating amount is 5 ml / m ² , and the dried film thickness is about 0.3 μm, dried at 180 ° C. for 5 minutes, and further, the undercoat coating solution C is wet-coated with the bar coater. An undercoating support was prepared by applying the solution in an amount of 3 ml / m ² and a dry film thickness of about 0.03 μm and drying at 180 ° C. for 5 minutes.

A silver salt of a fatty acid was prepared as follows. << Preparation of Silver Salts of Fatty Acids 1 to 7 >> 43.8 g of behenic acid (product name: Edenor C22-85R) manufactured by Henkel, 730 ml of distilled water, tert-
Mix 60 ml of butanol and 117 ml of 1N-NaOH aqueous solution, and at 79 ° C.
The reaction was stirred for 1 hour. Then, an aqueous solution of 19.2 g of silver nitrate
112.5 ml was added over 10 minutes, left as it was for 5 minutes, and cooled to 30 ° C. Thereafter, the solid content was separated by suction filtration, and the solid content was washed with water until the conductivity of the filtrate became 30 μS / cm. Thus, fatty acid silver salt 1 was obtained. The resulting solids are
It was stored as a wet cake without drying. Also,
Immediately after the completion of the addition of the aqueous silver nitrate solution, Ca, Mg, Ce,
A 0.1 mol / l aqueous solution of nitrate of Al, Zn and Ba was added to 1 mol of silver nitrate and 1 mol of each metal ion was used.
Fatty acid silver salts 2 to 7 were prepared in the same manner as fatty acid silver salt 1, except that 1% was added.

<< Preparation of Silver Salts of Fatty Acids 8 to 14 >> 43.8 g of behenic acid (product name: Edenor C22-85R) manufactured by Henkel, 79 ml of distilled water, 117 ml of 1N-NaOH aqueous solution, and 60 ml of isopropanol were mixed, and the mixture was mixed at 79 ° C. for 1 hour. The mixture was stirred and reacted to obtain a sodium behenate solution. Separately, an aqueous solution of 20.2 g of silver nitrate
Prepare 1 ml, keep the temperature at 25 ° C., keep the reaction vessel containing 630 ml of distilled water at 35 ° C., and stir the entire amount of the sodium behenate solution and the total amount of the aqueous silver nitrate solution at a constant flow rate of 5 ml. Added over minutes. At this time,
For 15 seconds after the start of the addition of the silver nitrate aqueous solution, only the silver nitrate aqueous solution was added, and then, the addition of the sodium behenate solution was started. After the completion of the addition of the silver nitrate aqueous solution, only the sodium behenate solution was added. . At this time, the temperature in the reaction vessel was set at 35 ° C., and care was taken not to increase the liquid temperature. Leave stirring for 5 minutes,
The temperature was lowered to 0 ° C. Then, the solid content was filtered off by suction filtration,
The solid was washed with water until the conductivity of the filtrate reached 30 μS / cm.
Thus, fatty acid silver salt 8 was obtained. The obtained solid content was stored as a wet cake without drying.

Immediately after the completion of the addition of the sodium behenate solution, a 0.1 mol / liter aqueous solution of a nitrate of Ca, Mg, Ce, Al, Zn or Ba was added in an amount of 1 mol% as a metal ion to 1 mol of silver nitrate. Except that the fatty acid metal salt 9
~ 14 were prepared.

<< Preparation of Silver Salts of Fatty Acids 15 to 21 >> 43.8 g of behenic acid (product name: Edenor C22-85R) manufactured by Henkel, 79 ml of distilled water, 117 ml of 1N-NaOH aqueous solution, tert-butanol
60 ml of the mixture was stirred and reacted at 79 ° C. for 1 hour to obtain a sodium behenate solution. Separately, an aqueous solution of 20.2 g of silver nitrate 1
Prepare 33.1 ml, keep the temperature at 25 ° C., keep the reaction vessel containing 630 ml of distilled water at 35 ° C., and stir the whole amount of the sodium behenate solution and the whole amount of the silver nitrate aqueous solution while stirring. Each was added over 5 minutes. At this time, only the silver nitrate aqueous solution is added for 15 seconds after the start of the silver nitrate aqueous solution addition, and then the sodium behenate solution is started to be added, and only the sodium behenate solution is added for 15 seconds after the completion of the silver nitrate aqueous solution addition. I did it. At this time, the temperature in the reaction vessel was set at 35 ° C., and care was taken not to increase the liquid temperature. The mixture was left to stir for 5 minutes, and the temperature was lowered to 30 ° C. Thereafter, the solid content was separated by suction filtration, and the solid content was washed with water until the conductivity of the filtrate became 30 μS / cm. Thus, fatty acid silver salt 15 was obtained. The obtained solid content was stored as a wet cake without drying. Immediately after the completion of the addition of the sodium behenate solution, C
a, 0.1molar of nitrate of Mg, Ce, Al, Zn, Ba
1 / l aqueous solution was added so that each metal ion was 1 mol% with respect to 1 mol of silver nitrate.
In the same manner as in the above, fatty acid silver salts 16 to 21 were prepared.

<< Preparation of Silver Salts of Fatty Acids 22 to 28 >> 43.8 g of behenic acid (Edenor C22-85R, manufactured by Henkel), 730 ml of distilled water, 117 ml of 1N-NaOH aqueous solution and 60 ml of tert-butanol were mixed, and the mixture was heated at 79 ° C. The mixture was stirred and reacted for 1 hour to obtain a sodium behenate solution. Separately, prepare 103.1 ml of an aqueous solution of 20.2 g of silver nitrate, keep the temperature at 25 ° C., keep the reaction vessel filled with 630 ml of distilled water at 35 ° C., and stir the whole amount of the sodium behenate solution and the silver nitrate. The whole amount of the aqueous solution was added over 5 minutes at a constant flow rate. At this time, only the silver nitrate aqueous solution is added for 15 seconds after the start of the silver nitrate aqueous solution addition, and then the sodium behenate solution is started to be added, and only the sodium behenate solution is added for 15 seconds after the completion of the silver nitrate aqueous solution addition. I did it. At this time, the temperature in the reaction vessel was set at 35 ° C., and care was taken not to increase the liquid temperature. The mixture was left to stir for 5 minutes, and the temperature was lowered to 30 ° C. Thereafter, the solid content was separated by suction filtration, and the solid content was washed with water until the conductivity of the filtrate became 30 μS / cm. Thus, a fatty acid silver salt 22 was obtained. The obtained solid content was stored as a wet cake without drying. Immediately after the completion of the addition of the sodium behenate solution, C
a, 0.1molar of nitrate of Mg, Ce, Al, Zn, Ba
1 / l aqueous solution was added so that each metal ion was 1 mol% with respect to 1 mol of silver nitrate.
In the same manner as in the above, fatty acid silver salts 23 to 28 were prepared.

The fatty acid silver salts 1 to 28 obtained above were dispersed by the following method to prepare dispersions 1 to 28 of the fatty acid silver salts.

<< Preparation of Fatty Acid Silver Salt Dispersions 1-28 >> A wet cake having a dry solid content of 100 g corresponding to each of the fatty acid silver salts 1 to 28 was added to polyvinyl alcohol (trade name: PVA-205, manufactured by Kuraray Co., Ltd.). ) 7.4 g and water were added to make a total amount of 385 g, and then predispersed with a homomixer.

Next, the pre-dispersed undiluted solution is dispersed in a dispersing machine.
(Product name: Microfluidizer M-110S-E
H, manufactured by Microfluidics International Corporation, using a G10Z interaction chamber) at a pressure of 1750 kg / cm ^2, and treated three times to obtain dispersions of fatty acid silver salts 1-28. Table 1 shows the particle sizes of the thus-obtained dispersions of fatty acid silver salts 1 to 28. The cooling operation in the dispersion was performed by installing a coiled heat exchanger before and after the interaction chamber, and adjusting the temperature of the refrigerant to a desired dispersion temperature.

[0195]

[Table 1]

<< Preparation of 25 wt% Dispersion of Reducing Agent >> 1,1-bis
(2-Hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane 80 g and Kuraray Co., Ltd. did. 800 g of zirconia beads having an average diameter of 0.5 mm were prepared, put into a vessel together with the slurry, and dispersed with a dispersing machine (1 / 4G sand grinder mill: manufactured by IMEX Co., Ltd.) for 5 hours to obtain a reducing agent dispersion.
The reducing agent particles contained in the reducing agent dispersion thus obtained had an average particle size of 0.72 μm.

<< Preparation of 20 wt% Dispersion of Mercapto Compound >> 32 g of a 20 wt% aqueous solution of 3-mercapto-4-phenyl-5-heptyl-1,2,4-triazole 64 g and modified polyvinyl alcohol poval MP203 manufactured by Kuraray Co., Ltd. 224 g of water was added thereto and mixed well to form a slurry. 800 g of zirconia beads having an average diameter of 0.5 mm were prepared, placed in a vessel together with the slurry, and dispersed with a disperser (1 / 4G sand grinder mill: manufactured by IMEX Co., Ltd.) for 10 hours to obtain a mercapto dispersion. The mercapto compound particles contained in the thus obtained dispersion of the mercapto compound had an average particle size of 0.67 μm.

<< Preparation of 30 wt% dispersion of organic polyhalogen compound >> 48 g of tribromomethylphenylsulfone and 3-tribromomethylsulfonyl-4-phenyl-5-tridecyl-
224 g of water was added to 48 g of 1,2,4-triazole and 48 g of a 20 wt% aqueous solution of modified polyvinyl alcohol poval MP203 manufactured by Kuraray Co., Ltd., and mixed well to form a slurry. 800 g of zirconia beads having an average diameter of 0.5 mm are prepared, put into a vessel together with the slurry, and dispersed with a dispersing machine (1 / 4G sand grinder mill: manufactured by IMEX Co., Ltd.) for 5 hours to obtain an organic polyhalogen compound dispersion. Was. The polyhalogen compound particles contained in the polyhalogen compound dispersion thus obtained had an average particle size of 0.74 μm.

<< Preparation of methanol solution of phthalazine compound >> 26 g of 6-isopropylphthalazine was dissolved in 100 ml of methanol and used.

<< Preparation of 20 wt% dispersion of pigment >> CI Pigmen
t 64 g of Blue 60 and 6.4 g of Demol N manufactured by Kao Corporation, 250 g of water
Was added and mixed well to obtain a slurry. Average diameter 0.5mm
Of zirconia beads was placed in a vessel together with the slurry, and dispersed by a dispersing machine (1 / 4G sand grinder mill: manufactured by Imex Co., Ltd.) for 25 hours to obtain a pigment dispersion. The pigment particles contained in the pigment dispersion thus obtained had an average particle size of 0.21 μm.

<< Preparation of Silver Halide Grain 1 >> Distilled water 1421
6.7 cc of a 1 wt% potassium bromide solution was added to the cc, and further, 8.2 cc of 1N nitric acid and a solution containing 21.8 g of phthalated gelatin were added while stirring in a titanium-coated stainless steel reaction vessel at 35 ° C.
The solution a1 diluted with 159 cc by adding distilled water to 37.04 g of silver nitrate and 32.6 g of potassium bromide in distilled water to a volume of 200 cc
Was prepared, and the entire amount of the solution a1 was added at a constant flow rate over 1 minute while maintaining the pAg at 8.1 by the control double jet method. (The solution b1 was added by a controlled double jet method.) Then, 30 cc of a 3.5 wt% aqueous hydrogen peroxide solution was added, and 3 w of benzimidazole was further added.
33.6 cc of a t% aqueous solution was added. Then, the solution a1 was again diluted with distilled water to 317.5 cc, and the solution b1 was dissolved with dipotassium hexachloride iridium acid so that the final concentration was 1 × 10 ^-4 mol per mol of silver with respect to the solution b1. Double the volume of solution b1 to 400
Using solution b2 diluted with distilled water to cc, the entire amount of solution a2 was added over 10 minutes at a constant flow rate by the controlled double jet method while maintaining the pAg at 8.1.
(Solution b2 is added by the controlled double jet method)
Then 0.5 of 2-mercapto-5-methylbenzimidazole
50cc of a wt% methanol solution is added, and pAg is further added with silver nitrate.
After raising the pH to 7.5, the pH was adjusted to 3.8 using 1N sulfuric acid, stirring was stopped, and the sedimentation / desalting / washing process was performed.
Add 5 g, add 1N sodium hydroxide, pH 6.0, pA
The dispersion was adjusted to g 8.2 to prepare a silver halide dispersion.

The grains in the completed silver halide emulsion are pure silver bromide grains having an average sphere equivalent diameter of 0.031 μm and a variation coefficient of the equivalent sphere diameter of 11%. The particle size and the like were determined from the average of 1000 particles using an electron microscope. The {100} plane ratio of these particles was determined to be 85% using the Kubelka-Munk method.

The above emulsion was heated to 50 ° C. while stirring, and N,
0.5 for N'-dihydroxy-N '', N ''-diethylmelamine
5 wt% methanol solution and 3.5 w of phenoxyethanol
5 cc of a t% methanol solution was added, and one minute later, 3 × 10 ⁻⁵ mol of sodium benzenethiosulfonate was added to 1 mol of silver. After 2 minutes, a solid dispersion of the spectral sensitizing dye 1 (aqueous gelatin solution) was added at 5 × 10 ⁻³ mol per mol of silver, and after 2 minutes, the tellurium compound was added at 5 × 10 ⁻⁵ mol per mol of silver. Aged for 50 minutes. Immediately before the completion of the ripening, the temperature was lowered by adding 1 × 10 ⁻³ mol of 2-mercapto-5-methylbenzimidazole per 1 mol of silver, and the chemical sensitization was terminated to prepare silver halide grains 1.

<< Preparation of silver halide grains 2 >> After dissolving 22 g of phthalated gelatin and 30 mg of potassium bromide in 700 ml of water and adjusting the pH to 5.0 at a temperature of 35 ° C., 18.6 g of silver nitrate and 0.9 g of ammonium nitrate are contained. An aqueous solution containing 159 ml of an aqueous solution and a 92: 8 molar ratio of potassium bromide and potassium iodide was pA
While maintaining the g at 7.7, it was added over 10 minutes by the control double jet method. Then, 1 ml in 476 ml and 1 liter of an aqueous solution containing 55.4 g of silver nitrate and 2 g of ammonium nitrate
X 10 ^-5 mol of an aqueous solution containing dipotassium hexachloride iridate and 1 mol of potassium bromide was added over 30 minutes by a control double jet method while keeping the pAg at 7.7, and then 4-hydroxy-6-methyl-1 was added. , 3,3a, 7-Tetrazaindene (1 g) was added, and the pH was further lowered to cause coagulation and sedimentation for desalination.
Then, 0.1 g of phenoxyethanol was added, pH 5.9, pAg
Adjusted to 8.2 silver iodobromide grains (iodine content core 8 mol%, average 2
Mol%, average size 0.05 μm, projected area variation coefficient 8%, {10
Preparation of (cubic particles having a {0} face ratio of 88%) was completed.

The silver halide grains thus obtained were heated to 60 ° C., and 85 μmol of sodium thiosulfate and 2,2
1.1 × 10 ⁻⁵ mol of 3,4,5,6-pentafluorophenyldiphenylphosphine selenide, 1.5 × 10 ⁻⁵ mol of tellurium compound, 3.5 × 10 ⁻⁸ mol of chloroauric acid, 2.7 × 10 ^{− Four}
After aging for 120 minutes, the mixture was rapidly cooled to 40 ° C., and 1 × 10 ^-4 mol of spectral sensitizing dye 1 and 5 × 10 ^-4 mol of 2-mercapto-5-methylbenzimidazole were added. The mixture was rapidly cooled to ° C. to obtain a silver halide emulsion 2.

<< Preparation of Emulsion Layer Coating Solution >> (Emulsion Layer Coating Solutions 1-28) 103 g of each of the fatty acid silver salt dispersions 1-28 obtained above, polyvinyl alcohol PVA-20
5 (manufactured by Kuraray Co., Ltd.) in a mixture of 5 g of a 20 wt% aqueous solution and keeping the mixture at 40 ° C., 23.2 g of the 25 wt% reducing agent dispersion, pigment CI Pigmen
1.2 g of a 20 wt% aqueous dispersion of t Blue 60, 10.7 g of a 30 wt% organic polyhalogen compound dispersion, 20 wt% dispersion of a mercapto compound
3.1 g was added. Then, ultrafiltration (UF) kept at 40 ° C
After adding 106 g of the purified SBR latex (40 wt%) and sufficiently stirring, 6 ml of a methanol solution of the phthalazine compound was added to obtain fatty acid silver salt-containing liquids 1 to 28. Also, 5 g of silver halide grains 1 and 5 g of silver halide grains 2 are mixed well in advance, and a fatty acid silver-containing liquid 1 is mixed with a static mixer immediately before coating.
To 28, respectively, to prepare emulsion layer coating solutions 1 to 28, which were directly sent to a coating die at a coating silver amount of 1.4 g / m ² .

The viscosity of the above emulsion layer coating solution was measured with a B-type viscometer of Tokyo Keiki Co., Ltd. and found to be 85 mPa · s at 40 ° C. (No. 1 rotor).
s]. The viscosity of the coating solution at 25 ° C. using an RFS Fluid Spectrometer manufactured by Rheometrics Far East Co., Ltd. was determined at a shear rate of 0.1, 1, 10, 100, 1000 [1 /
Sec] were 1500, 220, 70, 40, and 20 [mPa · s], respectively.

The UF purified SBR latex was obtained as follows.

The following SBR latex diluted 10-fold with distilled water was used for UF-purification module, FS03-FC-FUY03A1.
(Daisen Membrane System Co., Ltd.) diluted and purified until the ionic conductivity became 1.5 mS / cm. At this time, the latex concentration was 40% by weight. (SBR latex: -St (68) -Bu (29) -AA (3)-latex)
Average particle diameter 0.1μm, equilibrium water content 0.6wt at 25 ° C and 60% RH
%, Concentration 45 wt%, ionic conductivity 4.2 mS / cm (measurement of ionic conductivity using a conductivity meter CM-30S manufactured by Toa Denpa Kogyo Co., Ltd., and measuring the latex stock solution (40 wt%) at 25 ° C), pH 8 .2

<< Preparation of Emulsion Surface Intermediate Layer Coating Solution >> (Intermediate Layer Coating Solution) Polyvinyl alcohol PVA-205 (Kuraray)
772 g of a 10 wt% aqueous solution of methyl methacrylate / styrene / 2-ethylhexyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (copolymerization weight ratio 59
/ 9/26/5/1) Aerosol OT in 27.5wt% latex liquid 226g
2 ml of a 5 wt% aqueous solution (manufactured by American Cyanamid Co., Ltd.), 4 g of benzyl alcohol, 1 g of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate and 10 mg of benzoisothiazolinone were added to the intermediate layer. The solution was fed to a coating die at 5 ml / m ² . The viscosity of the coating solution was 21 mPa · s at 40 ° C. (No. 1 rotor) using a B-type viscometer.

<< Preparation of Emulsion Surface Protective Layer First Layer Coating Solution >> (Protective Layer First Layer Coating Solution) 80 g of inert gelatin was dissolved in water, 138 ml of a 10 wt% methanol solution of phthalic acid, and 28 ml of 1N sulfuric acid. Aerosol OT (American Cyanamid)
5 ml of a 5 wt% aqueous solution of phenoxyethanol 1 g was added,
Water was added so as to make the total amount 1000 g, thereby forming a coating solution for the first layer of the protective layer. The solution was fed to a coating die so as to have a concentration of 10 ml / m ² . The viscosity of the coating solution was measured using a B-type viscometer at 40 ° C (No. 1 rotor).
It was 17 [mPa · s].

<< Preparation of Emulsion Surface Protective Layer Second Layer Coating Solution >> (Protective Layer Second Layer Coating Solution) Inert gelatin (100 g) was dissolved in water, and N-perfluorooctylsulfonyl-N-propylalanine potassium salt was 5 wt%. 20 ml of solution, aerosol
16 ml of a 5 wt% solution of OT (manufactured by American Cyanamid Co., Ltd.), polymethyl methacrylate fine particles (average particle size 4.0 μm) 25
g, 44 ml of 1N sulfuric acid, 10 mg of benzoisothiazolinone and water to a total amount of 1555 g, and 445 ml of an aqueous solution containing 4 wt% chromium alum and 0.67 wt% phthalic acid were applied with a static mixer immediately before application. The mixture was used as a coating liquid for the second layer of the protective layer, and was fed to a coating die so as to have a concentration of 10 ml / m ² . The viscosity of the coating solution was 9 [mPa · s] with a B-type viscometer at 40 ° C. (No. 1 rotor).

<< Preparation of Back Surface Coating Liquid >> (Preparation of Solid Precursor Dispersion of Base Precursor) 64 g of a base precursor compound and 10 g of a surfactant Demol N manufactured by Kao Corporation were mixed with 246 ml of distilled water, and the mixed solution was mixed. Beads are dispersed using a sand mill (1/4 Gallon sand grinder mill, manufactured by AIMEX Co., Ltd.), and the average particle diameter is 0.2 μm.
The solid precursor dispersion liquid of the base precursor was obtained.

(Preparation of Dye Solid Particle Dispersion) 9.6 g of a cyanine dye compound and 5.8 g of sodium p-alkylbenzenesulfonate were mixed with 305 ml of distilled water, and the mixture was subjected to a sand mill (1/4 Gallon sand grinder mill, Amimex Co., Ltd.). )) To disperse the beads to obtain an average particle diameter of 0.
A dye solid fine particle dispersion of 2 μm was obtained.

(Preparation of antihalation layer coating liquid) Gelatin 17 g, polyacrylamide 9.6 g, solid fine particle dispersion of the above-mentioned base precursor 70 g, solid fine particle dispersion of the above dye 56 g, polymethyl methacrylate fine particles (average particle size 6.5 μm) 1.5 g, 2.2 g of sodium polyethylene sulfonate, 0.2 g of a 1% by weight aqueous solution of a coloring dye compound, 844 H ₂ O
The mixture was mixed to prepare an antihalation layer coating solution.

(Preparation of Coating Solution for Protective Layer) The container was kept at 40 ° C., and gelatin 50 g, polystyrene sodium sulfonate
0.2 g, N, N'-ethylenebis (vinylsulfoneacetamide) 2.4 g, t-octylphenoxyethoxyethaneethanesulfonate 1 g, benzoisothiazolinone 30 m
g, 32 mg of _{C 8 F 17 SO 3 K,} C 8 F 17 SO 2 N (C 3 H 7) (CH 2 CH 2 O) 4 (CH 2)
64 mg of _4- SO ₃ Na and 950 ml of H ₂ O were mixed to prepare a protective layer coating solution.

[0219]

Embedded image

<< Preparation of Photothermographic Materials 1-28 >> On the undercoated support described above, the coating amount of the antihalation layer was changed to 0.04 g / m ² of the solid fine particle dye, and the coating solution of the protective layer was converted to gelatin. after the coating amount is simultaneous multilayer coating so that the 1 g / m ^2, and create a dried antihalation back layer,
On the surface opposite to the back surface, the emulsion layer, the intermediate layer, the first protective layer, and the second protective layer were simultaneously coated in order from the undercoating surface by a slide bead coating method to prepare a photothermographic material sample. . The emulsion surface was applied without winding after coating the back surface.

The coating was performed at a speed of 160 m / min, the distance between the tip of the coating die and the support was set to 0.18 mm, and the pressure in the decompression chamber was set 392 Pa lower than the atmospheric pressure. In the subsequent chilling zone, the dry bulb temperature is 18 ° C and the wet bulb temperature is 12 ° C
After blowing the wind at an average wind speed of 7 m / sec for 30 seconds to cool the coating solution,
A dry air having a dry-bulb temperature of 30 ° C. and a wet-bulb temperature of 18 ° C. was blown out of the hole at an air velocity of 20 m / sec for 200 seconds to volatilize the solvent in the coating solution.

The photothermographic materials 1 to 28 thus prepared were evaluated by the following methods. << Evaluation of photographic performance >> After exposing the photosensitive materials 1 to 28 at an inclination of 8 degrees with respect to the normal with a 647 nm Kr laser sensitometer (maximum output 500 mW), processing (developing) at 120 ° C. for 15 seconds, The obtained image was evaluated with a densitometer.
The results of the measurement were evaluated in terms of Dmin and sensitivity (the reciprocal of the ratio of the amount of exposure that gives a density higher than Dmin by 1.0). The sensitivity of the photosensitive material 1 was set to 100. Dmin also
Evaluation was made based on a relative value when Dmin of the photosensitive material 1 was 100. The higher the sensitivity value and the lower the Dmin value,
The photographic performance is good.

<< Evaluation of forced storage stability >> Photosensitive materials 1-2
8 was cut to 30.5 cm × 25.4 cm, the corner was a round corner with an inner diameter of 0.5 cm, and 25 ° C.-50% R
It was left for 1 day under the condition of H, and 10 sheets of the photosensitive material were sealed in a bag made of a moisture-proof material, and further 35.1 cm.
The pieces were placed in a makeup box of 26.9 cm × 3.0 cm and aged at 50 ° C. for 5 days (forced aging). This sample and a sample prepared in the same manner as the forced aging except that the storage temperature was 4 ° C. for comparison were subjected to the same processing as in the evaluation of photographic properties, and the density of the fog portion was measured. The storage stability over time was evaluated as a fog increase rate.

(Fog increase rate) = [{(fog of forced forced aging sample) − (fog of comparative sample)} / {(highest concentration of comparative sample) − (concentration of support)} × 100 Low fog increase rate The longer the storage stability with time, the better.

<< Evaluation of Light-Irradiated Image Preservation >> A photosensitive material exposed and developed in the same manner as in the evaluation of photographic properties was stuck inside a glass window exposed to direct sunlight, and allowed to stand for one month. did. A: There is almost no change.・ ・ ・: There is a slight change in color tone, but it does not matter. Δ: Discoloration in the image area is observed, but practically acceptable. ×: Dmin discolored and density could not be increased.

Table 2 shows the results of the above three evaluations. According to the present invention, good Dmin can be obtained without deteriorating sensitivity.
It can be seen that the storage stability over time can be improved. Furthermore, in the photosensitive materials 16 to 21, the effect of further improving the image storability appeared, and the usefulness of the present invention was demonstrated.

[0225]

[Table 2]

Example 2 A fatty acid silver salt 29 was prepared in the same manner as the fatty acid silver salt 15 prepared in Example 1, and a fatty acid silver salt dispersion 29 was obtained as follows.

<< Preparation of Dispersion 29 of Silver Salt of Fatty Acid >> A wet cake equivalent to 100 g of dry solid content of silver salt of fatty acid 29 was added to polyvinyl alcohol (trade name, manufactured by Kuraray Co., Ltd.).
After adding 7.4 g of PVA-205) and water to make the total amount 385 g, the mixture was predispersed with a homomixer.

Next, this solution was placed in a 1/4 gallon vessel containing 912 g of zirconia beads having an average particle size of 1 mm, and the mixture was kept at 1000 rpm with a sand grinder mill (manufactured by IMEX Co., Ltd.) while maintaining the internal temperature at 20 ° C. Time dispersed.

The obtained dispersion liquid 29 of a silver salt of a fatty acid was coated in the same manner as in Example 1 to obtain a photothermographic material 29.

<< Evaluation of Surface State >> The photothermographic material 29 and the photothermographic materials 1 and 15 used in Example 1 were used to obtain a density of 1
Exposure development similar to photographic performance evaluation
Table 3 shows the value obtained by multiplying the standard deviation of the density measured by 10 cm in the coating width direction by 100 for each of the times. The smaller the value, the better the surface condition.

<< Evaluation of Photographic Performance and the Like >> In the same manner as in Example 1, evaluation of photographic performance, forced aging storage stability, and light irradiation image storage stability evaluation was performed on the photothermographic material 29 and the photothermographic material 1 of Example 1. , 15.

From Table 3, it can be seen that the photothermographic material 15 has little density fluctuation in the coating width direction and is suitable for practical use. On the other hand, the photothermographic material 29 using the dispersion of the fatty acid silver salt dispersed by the sand grinder mill was found to be inferior in surface condition and other performances, and the usefulness of the fine dispersion method according to the present invention is apparent.

[0233]

[Table 3]

[0234]

According to the present invention, a photothermographic material having low fog and excellent in storability over time and image storability can be obtained.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H123 AB00 AB03 AB23 AB28 AB30 BA00 BA14 BB00 BB08 BC00 BC12 CB00 CB03 4H006 AA02 AA03 AB76 AC47 AC90 BB14 BB31 BS10 BS70 4H048 AA02 AA03 AB76 AC47 AC90 BB14 BB31 VA20 VA50 VA50

Claims (7)

[Claims] 1. An aqueous solution containing silver ions, or a mixed solution of water and a tertiary alcohol having 4 to 6 carbon atoms, and water and carbon of an alkali metal salt of a fatty acid having a concentration of 7 wt% to 50 wt%. A method for preparing a silver salt of a fatty acid, comprising preparing a mixed solution of the tertiary alcohols of Formulas 4 to 6 and then simultaneously adding and mixing the liquid and the liquid to form a silver salt of a fatty acid. 2. The fatty acid has substantially 12 to 26 carbon atoms.
The method for preparing a fatty acid silver salt according to claim 1, which is a saturated fatty acid falling within the following range. 3. The method for preparing a fatty acid silver salt according to claim 1, further comprising a step of desalting after forming the fatty acid silver salt. 4. The fatty acid according to any one of claims 1 to 3, wherein the fatty acid silver salt is converted into an aqueous dispersion, and the aqueous dispersion is converted into a high-speed stream at a high pressure, and then the pressure is reduced to obtain a fine aqueous dispersion. A method for preparing a silver salt. 5. A photothermographic material comprising a silver salt of a fatty acid prepared in claim 1 and a photosensitive image-forming layer comprising a photosensitive silver halide, a reducing agent and a binder. 6. A coating solution for a photosensitive image forming layer, wherein a metal ion selected from Ca, Mg, Ce, Al, Zn and Ba is added in a non-halide form during the preparation of the fatty acid silver salt and immediately before coating. 6. The photothermographic material according to claim 5, further comprising a photosensitive image forming layer formed by using the following. 7. The photothermographic material according to claim 5, wherein a polymer latex is used as a binder.