JP2002049118A - Method for preparing particles of silver salt of organic acid and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently preparing particles of the silver salt of an organic acid by which particles of the silver salt of the organic acid formed by mixing an alkali metallic salt solution with a silver ion-containing solution can be refined without drawing as a solid material. SOLUTION: In the method for preparing particles of the silver salt of an organic acid by reacting a solution containing silver ions in water or a mixture of water and an organic solvent with a solution or suspension containing an alkali metallic salt of the organic acid in water, an organic solvent or a mixture of water and an organic solvent, the silver ion-containing solution and the alkali metallic salt-containing solution or suspension are mixed and reacted in a hermetically sealed mixing means and a by-product salt contained in the reactive liquid is removed during or after the reaction with an ultrafiltration membrane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently preparing organic acid silver salt particles by reacting a silver ion-containing solution with an organic acid alkali metal salt-containing solution. The present invention also relates to an apparatus for preparing organic acid silver salt particles having a low equipment cost and a high productivity.

[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 laser imagesetter or laser
There is a need in the art for photothermographic materials for medical diagnostic and photographic applications that can be exposed more efficiently by an imager and can form a sharp black image with high resolution and sharpness. I have. According to these photothermographic materials, a heat development system that does not require solution processing chemicals and that is simpler and does not damage the environment can be supplied to customers. There is a similar requirement in the field of general image forming materials, but in particular, medical images require high-quality images with excellent sharpness and granularity due to the need for fine depiction. From the viewpoint, there is a feature that an image having a cool black tone is preferred. At present, various hard copy systems using pigments and dyes, such as ink jet printers and electrophotographs, are distributed as general image forming systems, but there is no satisfactory system for outputting medical images.

On the other hand, a thermal image forming system using an organic acid silver salt is disclosed in, for example, US Pat. No. 3,152,904,
No. 3,457,075 and D.C. "Thermally Processed SilverSystems" by Klosterboer, Imaging Processes and Materials (Imagin)
gProcesses and Materials) Neblette 8th edition, J.M. Sturge, V.S. Walworth,
A. Edited by Shepp, Chapter 9, pp. 279, 1
989). In particular, the photothermographic material generally comprises a catalytically active amount of a photocatalyst (eg, silver halide), a reducing agent, a reducible silver salt (eg, an organic silver salt), and a color tone agent for controlling the color tone of silver as required. Is dispersed in a binder matrix. After the image exposure, the photothermographic material is heated to a high temperature (for example, 80 ° C. or higher), and is subjected to a redox reaction between a silver halide or a reducible silver salt (which functions as an oxidizing agent) and a reducing agent to form a black color. To form a silver image. The oxidation-reduction reaction is promoted by the catalytic action of the latent image of silver halide generated by exposure. Therefore, a black silver image is formed in the exposed area (U.S. Pat. No. 2,910,377, JP-B-43-49).
No. 24, etc.). A thermal image forming system using these organic acid silver salts can achieve image quality and color tone that are satisfactory as medical images.

The silver source used in such a system is generally a silver salt of an organic acid, and various production methods are known. For example, Japanese Patent Application Laid-Open Nos.
A method for preparing an organic acid silver salt in a coexisting solution of water and a poorly water-soluble solvent as described in JP-A-9-94619 and JP-A-53-68702;
No. 1, JP-A-54-4117 and JP-A-5-4117.
A method for preparing an organic acid silver salt in an aqueous solution as described in JP-A-4-46709, JP-A-57-1867.
No. 45, JP-A-47-9432 and U.S. Pat. No. 3,700,458, for example, a method for preparing an organic acid silver salt in an organic solvent. Basically, an organic acid is heated and melted in water at or above its melting point, sodium hydroxide or an alkali metal salt is added with vigorous stirring, and then a silver ion-containing solution is used to replace the alkali soap with silver soap. Prepared by adding

[0005] Such an alkali soap forms micelles in an aqueous solution, and appears as a cloudy liquid in appearance. 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 uniform, it has been proposed to use a mixed solution of water and alcohol as the solvent.
No. 07 gazette. In addition, since alkali soap exhibits alkalinity, silver soap is produced under high pH. However, when a silver ion-containing solution is added to an alkaline solution, silver oxide is generated as a by-product. Further, a trace amount of reducing contaminants unavoidable in production have a high reducing property due to a high pH, and cause unintended silver nuclei. Such by-products are a significant disadvantage in the performance of such photothermographic materials, especially in that they cause unwanted fog. JP-A-55-406 for the purpose of obtaining a homogeneous liquid in order to suppress the generation of by-products
In the method described in JP-A-07-07, the problem of fog is not solved.

On the other hand, 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 solution and a silver nitrate solution. The simultaneous addition of a solution is described. This method can reduce at least the reaction under a high pH to a neutral range and is a preferable method for reducing the amount of silver oxide produced. However, since isopropyl alcohol has a weak reducing property, it is a means for completely solving fog. Does not reach. The silver behenate particles formed by this method have a particle size of 0.04 to 0.05 μm.
This is a needle-like particle grown anisotropically in the two-dimensional direction, and there is no description on control of particle size or particle shape. Japanese Patent Application Laid-Open No. 11-349325 discloses that the temperature of a reaction field at the time of simultaneous metered addition of an alkali metal salt solution and a silver ion-containing solution is reduced to thereby produce scaly particles different from conventional needle-like particles. A method of forming is disclosed. According to this method, by controlling the temperature of the reaction field, scaly particles can be obtained on the low-temperature side and needle-like particles can be obtained on the high-temperature side. Has not been reached.

In order to obtain a practically usable uniform dispersion using a coating solution containing a silver salt of an organic acid, it is necessary that the silver salt of an organic acid is finely dispersed without aggregation in a solvent. Therefore, it is necessary to develop a method for dispersing the organic acid silver salt in fine particles. Usually, for example, the imaging processes
As described in And Materials, a method is employed in which hydrophobic organic acid silver dispersion particles are formed, separated by filtration, taken out as a solid, and then mixed with a dispersant and redispersed. The method for dispersing the organic acid silver salt in fine particles is as follows:
In the presence of a dispersing aid, a known means of micronization (for example, high-speed mixer, homogenizer, high-speed impact mill, Banbury mixer, homomixer, kneader, ball mill, vibrating ball mill, planetary ball mill, attritor, sand mill, bead mill, colloid mill, Jet mills, roller mills, tron mills, high-speed stone mills) are known to mechanically disperse them. However, in these methods, only a coating liquid having a large amount of agglomerated particles and consequently poor coating surface quality is obtained. Not only is it not possible, but also the probability of indiscriminately crushing the primary particles of the organic acid silver that originally crystallized as a poorly water-soluble salt is high, which causes silver nuclei to form on the cleavage plane of the crystal and causes fog to increase. .

Therefore, several methods have been proposed in which the primary particles obtained during the reaction of the alkali metal salt solution and the silver ion-containing solution are used as they are, instead of once taking out the organic acid silver as a solid content and finely dispersing it. I have. For example, JP-A-8
JP-A-234358 discloses a method of desalting an organic acid silver salt particle dispersion obtained by adding silver nitrate to an aqueous dispersion in which fine particles of an organic acid alkali salt are dispersed by ultrafiltration. I have. Further, this publication discloses that dispersion stability is increased by preliminarily containing a water-soluble protective colloid such as polyvinyl alcohol or gelatin and then performing an ultrafiltration operation. However, the shape of the organic acid silver particles obtained by this method is limited to acicular. In addition, since it is difficult to control the particle size by this method, low fog, high blackening density, and low haze performance desired for a photothermographic material have not yet been stably obtained.

Japanese Patent Application Laid-Open No. 9-127643 discloses that an organic acid silver salt particle dispersion obtained by simultaneous metered addition of an alkali metal salt solution and a silver nitrate solution is directly desalted by dialysis or ultrafiltration. A method is disclosed. According to this method, at least the primary particles obtained at the time of crystallization of the organic acid silver salt can be directly introduced into the photosensitive layer without damaging the particles. However, it cannot be said that this is a means for obtaining a practical uniform dispersion in this respect. Further, Japanese Patent Application Laid-Open No. 9-127463 discloses a method in which a dispersant is used in combination as in Japanese Patent Application Laid-Open No. 8-234358. However, there is no mention of the type of preferred dispersant, the salt concentration when the organic acid silver particles are formed is high, and the particle shape and particle size are controlled in the presence of an organic solvent such as isopropyl alcohol, and the dispersion stability is high. The invention has not been completed.

In order to obtain fine and monodispersed organic acid silver salt particles, it is necessary to mix vigorously while adding a solution containing an alkali metal salt and a solution containing a silver ion. In particular, a solution of an alkali metal salt of an organic acid dissolved at a high temperature drops at the moment of its addition and precipitates. If the dilution rate or the flow is slow, the solution grows into large coarse particles. Therefore, when adding to a tank having a gas / liquid interface,
When the stirring speed is increased, air entrainment occurs, but the silver salt of the organic acid is extremely hydrophobic and adsorbs on the surface of the entrained foam to stabilize the foam and prevent it from breaking. The particles aggregate together. The liquid containing air in this way becomes a whipped cream-like liquid with high viscosity.
This is an obstacle to obtaining a uniform reaction. Further, in the case of a liquid containing bubbles and causing aggregation of particles, when used in an ultrafiltration operation, a reduction in filtration speed due to adhesion to a membrane surface and an increase in filtration pressure due to high viscosity are problematic. In addition, when a hollow fiber type filtration membrane is used, there is a problem such as occurrence of blockage of a flow channel due to progress of particle aggregation. These problems are obstacles when applied to practical manufacturing facilities.

As described above, a method for stably producing a silver salt of an organic acid which can control the particle size and the particle shape independently and has low fog has been found. That is, the solution containing the alkali metal salt and the solution containing the silver ions are mixed vigorously while being added to generate organic acid silver salt particles without causing air entrainment or aggregation of the particles, and the generated organic acid silver salt is removed. There has not yet been found a method of utilizing the obtained primary particles as they are, instead of once taking out as a solid content and finely dispersing them.

[0012]

SUMMARY OF THE INVENTION In view of these problems of the prior art, the present invention provides an organic silver salt particle produced by mixing an alkali metal salt solution and a silver ion-containing solution as a solid. It is an object of the present invention to provide a method for efficiently preparing organic acid silver salt particles which can be purified without using any method. Another object of the present invention is to provide a method and an apparatus for preparing organic acid silver salt particles having a low equipment cost, a small equipment space, and a high productivity.

[0013]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that the above-mentioned problems can be solved by the following means, and have completed the present invention. That is, the present invention provides a silver ion-containing solution containing silver ions in water, or a mixture of water and an organic solvent, and a solution containing an organic acid alkali metal salt in water, an organic solvent, or a mixture of water and an organic solvent. Alternatively, in the method of preparing organic acid silver salt particles by reacting with a suspension containing an organic acid alkali metal salt-containing liquid, the silver ion-containing solution and the organic acid alkali metal salt-containing liquid are mixed in a closed mixing means. An organic acid characterized in that it comprises a step of removing by-product salts contained in the reaction solution using an ultrafiltration membrane in parallel with or after the reaction, or after the reaction. A method for preparing silver salt particles is provided. As a preferred embodiment of the preparation method of the present invention, at least a part of a mixture obtained after reacting the silver ion-containing solution and the organic acid alkali metal salt-containing solution mixed in the closed mixing means is circulated, An embodiment in which at least one type of dispersant is added before the start of the reaction to the end of the purification using the ultrafiltration membrane; An embodiment in which at least a nonionic polymer dispersant having a molecular weight cutoff of 5 to 50 times the ultrafiltration membrane is used; the concentration of the nonionic polymer dispersant is from 0.1 to 30 mass of the organic acid silver solid. %; An embodiment using at least any one of polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, and hydroxypropyl cellulose as the dispersant; The by-product salt was removed by ultrafiltration constant volume dilution 2-20 fold, can be mentioned a mode in which to concentrate the dispersion concentration to 10 to 50 mass%. In this specification, “to” indicates a range including numerical values described before and after the range as a minimum value and a maximum value, respectively.

The present invention also provides a first supply means for supplying a silver ion-containing solution containing silver ions in water or a mixture of water and an organic solvent to a closed mixing means; water, an organic solvent, or water and an organic solvent. Second supply means for supplying a solution or suspension containing an organic acid alkali metal salt in a mixture with a solvent to a closed mixing means; water or a mixture of water and an organic solvent; Third supply means for supplying to the closed mixing means; closed mixing means for mixing the supplies from the first supply means, the second supply means and the third supply means to produce a liquid containing organic acid silver salt particles; Storing means for discharging and storing the generated organic acid silver salt particle-containing liquid from the closed mixing means; fourth supply means for supplying the organic acid silver salt particle-containing liquid in the storing means from the storing means to the ultrafiltration step; Liquid containing organic acid silver salt particles The by-product salts to provide an apparatus for preparing an organic acid silver salt grains characterized in that it comprises a purification means for removing by ultrafiltration. Further, the present invention provides a first supply means for supplying a silver ion-containing solution containing silver ions in water or a mixture of water and an organic solvent to a closed mixing means; water, an organic solvent, or a mixture of water and an organic solvent. A second supply unit for supplying an organic acid alkali metal salt-containing liquid, which is a solution or suspension containing the organic acid alkali metal salt in the mixture, to the closed mixing unit;
Closed mixing means for mixing the supplies from the first supply means, the second supply means and the third supply means to produce a liquid containing organic acid silver salt particles; A storage means for discharging and storing from the closed mixing means; a third supply means for re-supplying at least a part of the generated liquid containing organic acid silver salt particles to the closed mixing means; A fourth supply means for supplying the liquid from the storage means to the ultrafiltration step; and a purification means for removing by-product salts from the organic acid silver salt particle-containing liquid by ultrafiltration. An apparatus for preparing is also provided.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The method for preparing organic acid silver salt particles and the apparatus for preparing organic acid silver salt of the present invention will be described below in detail. The method of the present invention is a method for preparing organic acid silver salt particles by reacting a solution containing silver ions with a liquid containing an organic acid alkali metal salt. The feature is that the silver ion-containing solution and the organic acid alkali metal salt-containing solution are mixed and reacted in a closed mixing means, and are contained in the reaction solution in parallel with the reaction or after completion of the reaction. The present invention comprises a step of removing by-product salts using an ultrafiltration membrane. The term "closed mixing means" as used herein means that the container is filled with the liquid to be mixed, and there is substantially no air phase.
A means for stirring and mixing a liquid in the absence of a liquid interface.

As the ion source of the silver ion-containing solution used in the present invention, a water-soluble silver salt can be used. Silver nitrate is preferably used as the water-soluble silver salt. The silver ion concentration in the silver ion-containing solution is 0.03 mol / L or more.
6.5 mol / L is preferred, and 0.1 mol / L to 5 m
ol / L is more preferred. The pH of the solution containing silver ions is 2
To 6, and more preferably pH 3.5 to 6. pH
For adjustment, the silver ion-containing solution may be added with an acid and an alkali commonly used for pH adjustment. As a solvent for the silver ion-containing solution used in the present invention,
Either water or a mixed solution of an organic solvent and water is used. The type of the organic solvent used in the silver ion-containing solution is not particularly limited as long as it is miscible with water. However, those which hinder photographic performance are not preferred. Preferred organic solvents are water-miscible alcohols and acetone, and it is particularly preferable to use tertiary alcohols having 4 to 6 carbon atoms. When a tertiary alcohol having 4 to 6 carbon atoms is used, it is preferably 70% by volume or less, more preferably 50% by volume or less, based on the total volume of the silver ion-containing solution. The temperature of the silver ion-containing solution is 0 ° C to 50 ° C.
C. is preferred, and 5 C. to 30 C. is more preferred.
15 ° C. is most preferred.

The organic acid constituting the organic acid alkali metal salt-containing liquid used in the present invention is relatively stable to light when a silver salt is used, but is exposed to a photocatalyst (a photosensitive silver halide). Latent image) and 80 in the presence of a reducing agent.
It is selected from those which form a silver image when heated to ℃ or more. As organic acids, especially those having 10 carbon atoms
It is preferred to use long-chain fatty carboxylic acids of ~ 30, preferably 15-28. Specifically, cellotic 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, tartaric acid, linoleic acid, butyric acid And camphoric acid, and mixtures thereof, preferably silver behenate, silver arachidate, silver stearate, silver oleate, silver laurate,
More preferably, silver caproate, silver myristate, silver palmitate, and mixtures thereof are used. Examples of the alkali metal constituting the organic acid alkali metal salt-containing liquid used in the present invention include sodium and potassium. The alkali metal salt of an organic acid can be prepared by adding sodium hydroxide, potassium hydroxide, or the like to the organic acid. At this time, it is preferable that the amount of the alkali is made equal to or less than the equivalent of the organic acid so that the unreacted organic acid remains. In this case, the amount of the residual organic acid is preferably 3 to 50 mol% based on the total organic acid, and 3 to 30 m
ol% is more preferable. 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 excess alkali.

The concentration of the alkali metal salt of the organic acid used in the present invention is preferably 5 to 50% by mass, more preferably 7 to 45% by mass, and more preferably 10 to 40% by mass. % Is particularly preferred.
Solvent of the organic acid alkali metal salt-containing liquid used in the present invention,
Any of water, an organic solvent, and a mixed solution of an organic solvent and water may be used. When a mixed solution of an organic solvent and water is used, the amount of the organic solvent is preferably from 3 to 70% by volume, more preferably from 5 to 50% by volume, based on the volume of water. At this time, since the optimum solvent composition changes depending on the reaction temperature, it is desirable to determine the optimum composition by trial and error. In the present invention, a tertiary alcohol having 15 or less carbon atoms, more preferably 10 or less carbon atoms, and particularly preferably 4 to 6 carbon atoms is preferably used as a solvent of the organic acid alkali metal salt-containing liquid in order to enhance the uniformity of the liquid. It is preferable to use a mixed solution of water and water. If the number of carbon atoms of the tertiary alcohol exceeds 6, the compatibility with water may decrease, which may be undesirable. Among the tertiary alcohols having 4 to 6 carbon atoms,
It is most preferred to use tert-butanol which is most compatible with water. Alcohols other than the tertiary alcohol have a reducing property and may be unfavorable because they cause adverse effects when forming the organic acid silver salt. The temperature of the organic acid alkali metal salt-containing liquid added for the reaction is preferably maintained at a temperature necessary to avoid the crystallization and solidification of the organic acid alkali metal salt. Specifically, 50 ° C
To 90 ° C is preferable, and 60 ° C to 85 ° C is more preferable.
65 ° C to 85 ° C is most preferred. Further, in order to control the temperature of the reaction to be constant, it is preferable that the temperature is controlled to be constant at a certain temperature selected from the above range. For pH adjustment, acids and alkalis usually used for pH adjustment can be added to the organic acid alkali metal salt-containing liquid.

The silver ion-containing solution and organic acid alkali metal salt-containing solution used in the present invention include, for example, JP-A-62-650.
No. 35, a compound represented by the general formula (1), a water-soluble group-containing N-heterocyclic compound described in JP-A-62-150240, and JP-A-50-101019.
Inorganic peroxides as described in JP-A-51-
It is possible to add a sulfur compound as described in JP-A-78319, a disulfide compound as described in JP-A-57-643, hydrogen peroxide, and the like.

A method for preparing an organic acid silver by reacting a solution containing a silver ion and a liquid containing an alkali metal salt of an organic acid includes:
A method of gradually or rapidly adding a silver ion-containing solution to a closed mixing means containing an organic acid alkali metal salt-containing solution,
A method of gradually or rapidly adding a liquid containing an organic acid alkali metal salt prepared in advance to a closed mixing means containing a solution containing silver ions, and a method of sealing and mixing the previously prepared silver ion-containing solution and the liquid containing an organic acid alkali metal salt in a closed mixing means. Can be used at the same time. The rate of addition may be constant or a function of time. When the function is a function of time, any of the accelerated addition method, the deceleration addition method, and a combination of both can be adopted.

A preferred method is a method (simultaneous addition method) in which there is a timing during the process of simultaneously adding the silver ion-containing solution and the organic acid alkali metal salt-containing solution to the closed mixing means. According to the simultaneous addition method, the average particle size of the organic acid silver salt can be controlled and the distribution can be narrowed. In the case of the simultaneous addition method, it is preferable that 10 to 100% by volume of the total amount is added simultaneously, and 30 to 100% by volume.
Is more preferably added simultaneously, and 50 to 100
It is particularly preferred that volume% is added simultaneously. The silver ion-containing solution and the organic acid alkali metal salt-containing solution at the time of simultaneous addition are preferably substantially the same in mole. When any of them is added in advance, it is preferable to add a solution containing silver ions first. The degree of precedence is preferably from 0 to 50% by volume, particularly preferably from 0 to 25% by volume of the total amount of the silver ion-containing solution. Further, a method of adding while controlling the pH or silver potential of the reaction solution during the reaction as described in JP-A-9-127463 can be preferably used.

In the production method of the present invention, silver / silver after the reaction between the solution containing silver ions and the solution containing the alkali metal salt of organic acid is used.
The alkali metal ratio is preferably 1 to 20 mol% in excess of alkali, and more preferably 1 to 10 mol% in excess of alkali. The concentration of the silver salt of organic acid immediately after the reaction is preferably 1 to 20% by mass, more preferably 1 to 10% by mass.

As a method of forming the silver salt of an organic acid,
There are various other approaches. In order to obtain organic acid silver salt particles, it is generally preferable to reduce the solubility of the organic acid silver salt in the reaction field. Further, according to the study of the present inventors, it has been revealed that as the addition time of the silver ion-containing solution or the organic acid alkali metal salt-containing solution increases, the size of the formed organic acid silver salt particles decreases. . In order to obtain organic acid silver salt particles of the desired particle size,
The reaction time must be determined by trial and error.
In the present invention, the reaction conditions are preferably adjusted so that the concentration of the silver salt of the organic acid immediately after the reaction is 1 to 10% by weight.

A solvent can be added to the closed mixing means before the addition of the silver ion-containing solution or the organic acid alkali metal salt-containing solution. Usually, water is used as the solvent to be put in advance, but a mixed solution with a silver ion-containing solution and an organic solvent used for an organic acid alkali metal salt-containing solution is also used. In order to form the organic acid salt particles, at least one of the silver ion-containing solution, the organic acid alkali metal salt-containing solution, and the solution prepared in advance in the reaction field is in the form of a string of an organic acid alkali metal salt. It is preferable to contain an organic solvent in an amount capable of forming a substantially transparent solution, not an aggregate or micelle. Further, it is preferable that water and a tertiary alcohol are present in the reaction solution when the silver ion-containing solution and the organic acid alkali metal salt-containing solution are added. At this time, the carbon number of the tertiary alcohol is preferably 15 or less, more preferably 10 or less,
Particularly preferred is 4 to 6. The weight ratio of the tertiary alcohol to water is preferably 0.01 to 10,
More preferably, it is 0.03 to 1. The temperature of the liquid in the closed mixing means is preferably 5 ° C to 75 ° C, and more preferably 6 ° C to 75 ° C in order to improve the performance as a photographic light-sensitive material.
The temperature is more preferably 60 ° C, particularly preferably 10 ° C to 50 ° C. It is preferable to control the temperature to a certain value selected from the above temperatures throughout the entire process of the reaction, but it is also preferable to control the temperature in several temperature patterns within the above temperature range.

The temperature difference between the liquid containing the organic acid alkali metal salt and the liquid in the closed mixing means is preferably from 20 to 85 ° C, more preferably from 30 to 80 ° C. In this case, the temperature of the organic acid alkali metal salt-containing liquid is preferably higher. Thereby, the high-temperature organic acid alkali metal salt-containing solution is rapidly cooled, and the rate at which the liquid is precipitated in the form of microcrystals, and the rate at which the organic acid silver salt is converted by the reaction with the water-soluble silver salt, are preferably controlled. Crystal morphology, crystal size,
The crystal size distribution can be preferably controlled. At the same time, the performance as a heat-developable image recording material, in particular, a heat-developable photosensitive material can be further improved.

For example, in order to prepare a scaly organic silver salt which is preferable in the present invention, a silver ion-containing solution and a tertiary alcohol aqueous solution containing an organic acid alkali metal salt are reacted by closed mixing means (closed mixing). (Including the step of adding a tertiary alcohol aqueous solution containing an organic acid alkali metal salt to the liquid in the means), the liquid in the closed mixing means (the silver ion-containing solution previously placed in the container, Alternatively, when the silver ion-containing solution is added simultaneously with the tertiary alcohol aqueous solution containing the organic acid alkali metal salt from the beginning without prior addition, water or a mixed solvent of water and the tertiary alcohol is used. Water or a mixed solvent of water and a tertiary alcohol may be added in advance.) And a third alcohol containing an organic acid alkali metal salt to be added. The temperature difference between the aqueous solution 20 ° C. to 85
C. is preferred. By maintaining such a temperature difference during the addition of the aqueous tertiary alcohol solution containing the organic acid alkali metal salt, the crystal form and the like of the organic acid silver salt are preferably controlled. The tertiary alcohol may be added at any time during the preparation of the organic acid silver salt. However, it is preferable to add the tertiary alcohol during the preparation of the organic acid alkali metal salt and dissolve the organic acid alkali metal salt before use. The amount of the tertiary alcohol can be arbitrarily used in a mass ratio of 0.01 to 10 with respect to water as a solvent at the time of preparing the silver salt of an organic acid. preferable.

In order to rapidly lower the temperature of the solution after the reaction between the silver ion-containing solution and the organic acid alkali metal salt-containing solution, the silver ion-containing solution and the organic acid alkali metal salt-containing solution to be supplied to the closed mixing means are prepared in advance. It may be cooled. Alternatively, cooling may be provided by providing a heat exchanger between the closed mixing means itself, the closed mixing means and the tank, or before the closed mixing means. The temperature of the solution after the reaction between the silver ion-containing solution and the organic acid alkali metal salt-containing solution is preferably from 5 ° C.
70 ° C, more preferably 10 ° C to 50 ° C, particularly preferably 20 ° C to 45 ° C. Further, the cooling rate is 0.05 to 10 seconds after the reaction liquid meets, preferably 0.05 to 10 seconds.
By reaching the target temperature in seconds to 5 seconds, more preferably 0.05 seconds to 1 second, the performance as a photographic light-sensitive material can be further improved.

In the method of the present invention, a dispersant is added to the system before the reaction between the silver ion-containing solution and the organic acid alkali metal salt-containing solution is started until the purification by the ultrafiltration membrane is completed. Is preferred. The method of addition is not particularly limited,
For example, it can be contained in 1 to 3 kinds of a solution containing a silver ion, a solution containing an alkali metal salt of an organic acid, and a solution previously placed in a reaction vessel. Further, it may be separately added as a dispersant, or may be mixed with another component and added as an additive. When added as such a dispersant or additive, any of water, an organic solvent, and a mixture of water and an organic solvent can be used as the solvent. These addition methods may be used in any combination.

The kind of the dispersant used in the present invention is not particularly limited. For example, a dispersant having a molecular weight of more than 3000 can be used. Examples of such dispersants include synthetic anions such as polyacrylic acid, naphthalene sulfonic acid polymer, acrylic acid copolymer, maleic acid copolymer, maleic acid monoester copolymer, and acryloylmethylpropanesulfonic acid copolymer. Polymer; semi-synthetic anionic polymer such as carboxymethyl starch and carboxymethyl cellulose; anionic polymer such as alginic acid and pectic acid; and other polyvinyl alcohols (for example, trade name: PVA-217, average degree of polymerization: about 170)
0), known polymers such as polyvinylpyrrolidone, carboxymethylcellulose, hydroxypropylcellulose, and hydroxypropylmethylcellulose, and naturally occurring polymer compounds such as gelatin can be appropriately selected and used.

In the present invention, it is preferable to use a nonionic polymer dispersant. More preferably, a nonionic polymer dispersant capable of dispersing an organic acid silver salt and soluble in a reaction aqueous solvent, wherein the molecular weight results from the reaction between a silver ion-containing solution and an organic acid alkali metal salt-containing liquid. Those having 5 to 50 times the molecular weight cut-off of the ultrafiltration membrane used for desalting by-product salts are mentioned. As such a dispersant, polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, and hydroxypropyl cellulose are preferably used. The concentration of the dispersant used in the present invention is 0.1 to 30% by mass, particularly 0.5 to 30% by mass, based on the organic acid silver salt.
The range of mass% is preferred. The time of addition of the dispersant is not particularly limited, but in order to prevent inhibition of the organic acid silver salt reaction,
It is preferable that the reaction be completed after the reaction of the silver salt of an organic acid and before the completion of the ultrafiltration operation.

Unlike the present invention, when a dispersing agent is not contained in the system, the silver salt of an organic acid is extremely hydrophobic, so that not only cross-linking between particles progresses with time, but also a liquid feeding operation and an ultra-low Aggregation remarkably progresses due to a shear field or a pressure field when passing through the filtration membrane. Further, under a high ionic strength atmosphere before the desalting operation, the surface charges of the organic acid silver salt particles are shielded, and the silver salt of the organic acid becomes more easily aggregated. To alleviate this state, it is desirable to set the pH high so as to promote the dissociation of the species present on the particle surface. However, if the alkaline atmosphere is too high, the action of silver oxide or an impurity reducing agent is enhanced, causing fogging. Therefore, in order to prevent agglomeration, in desalting operation by ultrafiltration, the electric conductivity is less than 2,000 μS / cm,
Until the pH of the dispersion reaches 6 μS / cm or more,
As described above, it is necessary to keep preferably 6 to 8. Even when a dispersant is used as in the present invention, it is preferable that the pH of the dispersion is controlled within this range.

In the method of the present invention, mechanical dispersion may be carried out by a disperser within a range not accompanied by deterioration of photographic properties.
As a dispersion method, it is preferable to obtain a dispersion of organic acid silver salt particles, convert the dispersion to a high-speed flow at high pressure, and then re-disperse by reducing the pressure to obtain a fine water dispersion.
In this case, the dispersion medium is preferably only water,
If it is 0% by mass or less, it may contain an organic solvent.

For the dispersion apparatus and the technique used for performing the above-described redispersion method, see, for example, “Dispersion Rheology and Dispersion Technique” (Toshio Kajiuchi, Hiroki Usui)
Author, 1991, Shinzansha Publishing Co., Ltd., p357-40
3), “Progress of Chemical Engineering Vol. 24,” edited by The Society of Chemical Engineers, Tokai Branch, 1990, Maki Shoten, p184-1
85), JP-A-59-49832, U.S. Pat.
No. 533254, Japanese Unexamined Patent Application Publication No. 8-137404, Japanese Unexamined Patent Application Publication No. 8-238848, Japanese Unexamined Patent Application Publication No.
No. 25, JP-A-1-94933, etc., the redispersion method used in the present invention is that after a water dispersion containing at least an organic acid silver salt is pressurized by a high-pressure pump or the like and fed into a pipe. Through a narrow slit provided in the pipe,
Thereafter, it is preferable that the dispersion is finely dispersed by causing a sharp pressure drop in the dispersion.

If a photosensitive silver halide salt coexists at the time of dispersing the organic acid silver salt, fog may increase and the sensitivity may be significantly reduced. For this reason, it is preferred that the photosensitive silver halide salt is not substantially contained at the time of dispersion. The photosensitive silver halide salt in the aqueous dispersion to be dispersed is 0.1 mol% or less based on 1 mol of the organic acid silver salt in the liquid,
It is desirable not to actively add a photosensitive silver halide salt. Instead of mechanically dispersing, fine particles may be formed by coarsely dispersing in a solvent by controlling the pH and then changing the pH in the presence of a dispersing aid. At this time, an organic solvent may be used as a solvent used for the coarse dispersion, and the organic solvent is usually removed after the completion of the fine particle formation.

The method of the present invention is characterized in that by-product salts contained in the reaction solution are removed by ultrafiltration in parallel with the reaction of silver ions with the alkali metal salt of an organic acid or after the completion of the reaction. There are features. As a method of ultrafiltration performed in the present invention, a method used for desalting / concentrating a silver halide emulsion can be adopted. For example, Research Disclosure No. 10208
(1972), No. 13122 (1975) and N
o. 16351 (1977). The pressure difference and flow rate that are important as operating conditions are
Haruhiko Oya, Handbook of Membrane Utilization Technology, Koshobo Publishing (1
978), and can be selected with reference to the characteristic curve described on p. 275. However, in treating the aqueous dispersion of the target organic acid silver salt, it is necessary to find optimal conditions for suppressing aggregation and fogging of particles. is there.

As the ultrafiltration membrane, a plate type, spiral type, cylindrical type, hollow fiber type, hollow fiber type, etc. already incorporated as a module are available from Asahi Kasei Co., Ltd., Daicel Chemical Co., Ltd., Toray Co., Ltd. It is commercially available from Nitto Denko Corporation or the like, but a spiral type or a hollow fiber type is preferable from the viewpoint of the total membrane area and the cleaning property. Examples of ultrafiltration membrane materials include polysulfone, polyphenylsulfone, polyethersulfone, and polyacrylonitrile.
Examples of the module form include a flat membrane, a hollow fiber membrane, and a tubular membrane. In addition, the molecular weight cutoff as an index of the threshold value of the component that can pass through the membrane needs to be determined from the molecular weight of the dispersant used. In the present invention, it is preferable to use one having a molecular weight of 1,500 to 50,000, and more preferably one having a molecular weight of 4,000 to 50,000.

In the present invention, it is preferable that the concentration of the silver salt of the organic acid immediately after the reaction is concentrated to 15 to 40% by mass, more preferably 15 to 25% by mass, and then the desalting treatment is performed. Also,
It is preferable to keep the liquid temperature low after the particle formation until the desalting operation proceeds. This is because, when the organic solvent used for dissolving the alkali metal salt of the organic acid is penetrating into the generated organic silver salt particles, the shearing field when passing through the liquid feeding operation or the ultrafiltration membrane or This is because silver nuclei are easily generated by the pressure field. For this reason, in the present invention, it is desirable to perform an ultrafiltration operation while maintaining the temperature of the organic acid silver particle dispersion at 1 to 30 ° C, preferably 5 to 25 ° C.

As a method of replenishing the solvent that is lost due to membrane permeation, either a constant volume type in which the solvent is continuously added or a batch type in which the solvent is intermittently added may be adopted. In the present invention, it is preferable to employ a constant volume equation in which the desalting time is relatively short. Pure water (which may contain a pH adjuster) obtained by ion exchange or distillation is used as the solvent to be replenished in this manner. The concentration of the agent may decrease, causing aggregation.
For this reason, it is preferable to supplement the surfactant in order to keep the surfactant concentration at a certain level and suppress aggregation. In particular, during the high salt concentration atmosphere at the beginning of the desalting operation and during the presence of an organic solvent such as a tertiary alcohol, the silver salt of the organic acid is in a state in which it is likely to aggregate. It is desirable to keep the concentration 5 to 100 times. Specifically, the concentration of the surfactant that leaks out is quantified by spectral absorption or liquid chromatography, and a solution having the same concentration may be continuously added as a replenisher, or a higher concentration of the surfactant may be added. The activator solution may be added intermittently.

Further, since the silver salt of an organic acid is extremely hydrophobic, flocculation may be remarkably progressed by a liquid feeding operation or a shearing field or a pressure field when passing through an ultrafiltration membrane.
Furthermore, under the high ionic strength atmosphere at the beginning of the desalting operation,
The surface charge of the silver salt of the organic acid is shielded, and the silver salt is easily aggregated. To alleviate this state, for example, if an anionic surfactant is added in advance,
A method of adding another ionic surfactant having a different anionic hydrophobic group having 8 to 40 carbon atoms during the desalting operation can be adopted. As for the addition method, the concentration of the leaking surfactant is quantified by spectral absorption or liquid chromatography as described above, and a solution having the same concentration may be added continuously as a replenisher, or High concentration surfactant solutions may be added intermittently.

When the molecular weight cut off of the ultrafiltration membrane is unknown,
The dispersant used may be filtered and the rejection may be calculated from the concentration of the surfactant leaking into the permeate. For example, when a surfactant is used, the rejection R of the ultrafiltration membrane is defined by the following equation, where Ci is the concentration of the stock solution and Co is the concentration leaking into the permeate. R = (Ci-Co) / Ci * 100 [%] The rejection in the method of the present invention is preferably less than 50%.

According to a preferred embodiment, desalting is carried out by ultrafiltration, and after the electric conductivity of the silver salt of an organic acid is reduced, for example, a nonionic polymer dispersant is added before the completion of the desalting operation. be able to. The electric conductivity at this time is 2,
000 μS / cm or less is preferable. In this case, for example, an operation of adding pure water in an amount corresponding to the amount of the anionic surfactant solution permeated through the ultrafiltration membrane in order to remove the anionic surfactant and replace it with the nonionic polymer dispersant, The so-called constant volume dilution operation is preferably performed 2 to 20 times.

Further, in the present invention, it is also possible to carry out an ultrafiltration operation while adding a poor solvent for the dispersant used after the electric conductivity has reached less than 1,000 μS / cm as the desalting progresses. it can. In a low ionic strength atmosphere, a stabilizing effect due to the charge on the surface of the particles is exhibited, so that aggregation does not occur even if the protective effect of the dispersant is reduced. Not only that,
The viscosity of the whole dispersion increases due to the increase in interparticle repulsion,
The filtration operation becomes difficult. In order to avoid this, it is desirable to add a poor solvent for the dispersant. After removing by-product salts by ultrafiltration, the dispersion can be further concentrated by ultrafiltration. In particular, the electric conductivity is not less than 20 μS / cm and 300 μm by removing by-product salts by ultrafiltration.
After reaching below S / cm, the dispersion concentration is preferably reduced to 10 to 50% by weight, more preferably to 10% by ultrafiltration.
It can be concentrated to ３０30% by weight.

In the present invention, Ca, Mg, Ce, A
Metal ions selected from 1, Zn, and Ba can be added 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. C
The addition time of the metal ion selected from a, Mg, Ce, Al, Zn, and Ba is not particularly limited, and the addition of the organic acid silver salt preparation to the solution, the prior addition to the reaction solution, the organic acid silver salt It may be at any time during or immediately after the formation, or immediately before the application, such as before or after the preparation of the coating solution. As the addition amount,
10 ^-3 to 10 ^-1 mol, preferably 5 × 10 ^{-3 to} 5 × 10 ^-2 mol, per 1 mol of the organic acid silver salt is preferred.

The prepared dispersion is stored with stirring for the purpose of suppressing sedimentation of fine particles during storage, or stored in a highly viscous state (for example, in a jelly state using gelatin) with a hydrophilic colloid. You can also.
Further, a preservative can be added for the purpose of preventing the propagation of various bacteria during storage. The organic acid silver salt dispersion according to the invention contains at least an organic acid silver salt and water.
The ratio of the silver salt of organic acid to water is not particularly limited, but when considering the formation of an efficient coating film, the production speed determined by the rheological properties for stable coating and the amount of dry moisture. More decisions need to be made. The proportion of the organic acid silver salt in the whole is preferably from 10 to 50% by weight, particularly preferably from 10 to 30% by weight.

The dispersion of the silver salt of an organic acid prepared by the production method of the present invention is finely dispersed in an aqueous solvent, and then mixed with an aqueous solution of a photosensitive silver halide to form a photosensitive material. It is preferably supplied as a coating solution for the hydrophilic image forming layer. When a heat-developable image recording material is prepared using such a coating solution, a heat-developable image recording material having low haze, low fog and high sensitivity can be obtained. On the other hand, when the photosensitive silver halide salt coexists when the organic acid silver salt is finely dispersed by converting it into a high-speed stream under high pressure, fog increases, and the sensitivity may be significantly reduced. It is desirable that the aqueous dispersion converted and converted to high pressure and high speed substantially contains no photosensitive silver halide salt. When an organic solvent is used instead of water as a dispersion medium, haze is increased, fog is increased, and sensitivity may be easily reduced. On the other hand, when the conversion method of converting a part of the organic acid silver salt in the dispersion liquid into the photosensitive silver halide salt is used instead of the method of mixing the photosensitive silver halide aqueous solution, the sensitivity may be reduced. .

The shape of the silver salt of an organic acid which can be used in the production of a heat-developable image recording material, in particular, a heat-developable photosensitive material is not particularly limited. Is mentioned. Among them, scaly organic silver salts are preferred. In the present specification, the scaly organic silver salt is defined as follows. The organic acid silver salt was observed with an electron microscope, and the shape of the organic acid silver salt particles was approximated to a rectangular parallelepiped. The sides of the rectangular parallelepiped were designated as a, b, and c from the shortest side (c is the same as b). Then, calculation is performed using the shorter numerical values a and b, and x is obtained as follows. x = b / a x is obtained for about 200 particles in this manner,
Assuming that the average value x (average), x (average) ≧ 1.5
The one satisfying the above relationship is scaly. Preferably 30
≧ x (average) ≧ 1.5, more preferably 20 ≧ x (average) ≧ 2.0. By the way, needle shape is 1 ≦ x (average) <
1.5. In the scaly particle, a can be regarded as the thickness of a tabular particle having a main plane with b and c as sides. The average of a is preferably from 0.01 μm to 0.23 μm, more preferably from 0.1 μm to 0.20 μm. c /
The average of b is preferably 1 to 6, more preferably 1.05
To 4, more preferably 1.1 to 3, particularly preferably 1.1 to 2.

The sphere-equivalent diameter of the silver salt of an organic acid prepared by the method of the present invention and used in the preparation of a heat-developable image recording material is preferably from 0.1 μm to 0.8 μm, and more preferably from 0.1 μm to 0.8 μm.
More preferably, it is from μm to 0.6 μm. Further, the long side / short side of the particles is preferably 1 to 4, and 1 to 3 is preferable.
Is more preferable, and it is particularly preferable that it is 1-2. Further, the aspect ratio (particle size (equivalent circle diameter) of the main plane / particle thickness) of the particles is preferably 2 to 30, and more preferably 2 to 15. Further, the thickness of the particles is preferably 0.01 μm to 0.20 μm, more preferably 0.01 μm to 0.15 μm. It is characterized in that grains satisfying the above requirements are included in 30% to 100% of the projected area of all grains.
More preferably, it contains 0% to 100%, and 70% to 10%.
It is particularly preferred to contain 0%.

The particle size distribution of the silver salt of an organic acid is preferably as monodispersed as possible. Assuming that the coefficient of variation is 100 times the value obtained by dividing the standard deviation of the particle diameter by the particle diameter, the coefficient of variation of the particle size of the organic acid silver salt particles is preferably 20% or less, more preferably 18% or less, and still more preferably 1% or less.
5% or less. As a measurement method, for example, a particle size (volume under load average diameter) obtained by irradiating a laser beam to a silver salt of an organic acid dispersed in a liquid and obtaining an autocorrelation function with respect to a time change of fluctuation of the scattered light. (So-called dynamic light scattering method).

The particle size (volume weighted average diameter) of the organic acid silver salt solid fine particle dispersion is determined, for example, by irradiating the solid fine particle dispersion dispersed in a liquid with a laser beam, and autocorrelating the fluctuation of the scattered light with time. It can be obtained from the particle size (volume weighted average diameter) obtained by obtaining the function. Average particle size 0.05 μm to 10.0 μm
Is preferable. More preferably, the average particle size is 0.1 μm to 5.0 μm, and still more preferably, the average particle size is 0.1 μm to 2.0 μm.

Next, an apparatus for preparing organic acid silver salt particles suitable for carrying out the method of the present invention will be specifically described.
The preparation apparatus of the present invention comprises a first supply means for supplying a silver ion-containing solution to a closed mixing means; a second supply means for supplying an organic acid alkali metal salt-containing liquid to a closed mixing means; water, or water and an organic solvent; Third supply means for supplying the mixture of the above to the closed mixing means; a closed state for mixing the supplies from the first supply means, the second supply means and the third supply means to produce a liquid containing silver salt of organic acid salt. Mixing means; storage means for discharging and storing the generated organic acid silver salt particle-containing liquid from the closed mixing means; fourth supply for supplying the organic acid silver salt particle-containing liquid in the storage means from the storage means to the ultrafiltration step Means; and a purification means for removing by-product salts from the liquid containing organic acid silver salt particles by ultrafiltration. FIG. 1 is a diagram showing a specific mode of this adjusting device. In the figure, a silver ion-containing solution is put into the additive component 1 tank 1, an organic acid alkali metal salt-containing solution is put into the additive component 2 tank 2, and the additive component 3 is added.
The reaction solvent is put into the tank 3 for use. Each liquid may be prepared in the tank, or may be prepared in advance outside the tank and then injected into the tank. Each liquid is sealed by the pumps 4, 5 and 6,
Guided inside. At this time, the flow rate of each liquid is measured by the flow meters 7, 8, and 9, and the flow rate is controlled. The respective liquids guided to the closed mixing means 10 are mixed in the closed mixing means and guided to the product liquid tank 11. The liquid in the product liquid tank 11 is further introduced into the ultrafiltration module 13 by the ultrafiltration step circulation pump 12 and subjected to the ultrafiltration step. At this time, the permeated water is measured by the flow meter 14. The dispersion that has been subjected to ultrafiltration is returned to the product liquid tank 11.

According to the present invention, apart from the above-mentioned apparatus, a first supply means for supplying a solution containing silver ions to a closed mixing means; a second supply means for supplying a liquid containing an organic acid alkali metal salt to a closed mixing means; (1) Closed mixing means for mixing the supplies from the second supply means and the third supply means to form a liquid containing organic acid silver salt particles; and sealingly mixing the liquid containing organic silver salt particles thus produced. Storage means for discharging and storing from the means; third supply means for re-supplying at least a part of the produced liquid containing organic acid silver salt particles to the closed mixing means;
A fourth supply unit for supplying the organic acid silver salt particle-containing liquid in the storage unit from the storage unit to the ultrafiltration step; and a purification unit for removing by-product salts from the organic acid silver salt particle-containing liquid by ultrafiltration. The present invention also provides an apparatus for preparing organic acid silver salt particles.

FIG. 2 is a diagram showing a specific embodiment of this adjusting device. In the figure, a silver ion-containing solution is put into the additive component 1 tank 15 and an organic acid alkali metal salt-containing solution is put into the additive component 2 tank 16. Each liquid is pump 1
It is guided into the closed mixing means 23 by 7 and 18. At this time, the flow rate of each liquid is measured and controlled by the flow meters 19 and 20. The respective liquids guided to the closed mixing means 23 are mixed in the closed mixing means and guided to the product liquid tank 24. A part of the liquid in the product liquid tank 24 is re-supplied into the closed mixing means 23 by the circulation pump 21, and the flow rate is measured by the flow meter 22. A part of the liquid in the product liquid tank 24 is introduced into the ultrafiltration module 26 by the ultrafiltration step circulation pump 25 and subjected to the ultrafiltration step. At this time, the permeated water is measured by the flow meter 14, and the dispersion subjected to ultrafiltration is returned to the product liquid tank 24. The product liquid tank 24 is replenished with pure water, and the flow rate is measured by a flow meter 28.

FIG. 3 is a diagram showing another specific embodiment of the adjusting device. In the figure, a silver ion-containing solution is placed in the additive component 1 tank 29 and an organic acid alkali metal salt-containing solution is placed in the additive component 2 tank 30. Each liquid is guided into the closed mixing means 37 by the pumps 31 and 32, respectively. At this time, the flow rates of the respective liquids are measured and controlled by the flow meters 33 and 34. The respective liquids guided to the closed mixing means 37 are mixed in the closed mixing means, and guided to the product liquid tank 38.
A part of the liquid in the product liquid tank 38 is re-supplied into the closed mixing means 37 by the circulation pump 35, and the flow rate is measured by the flow meter 36. A part of the liquid in the product liquid tank 38 is guided to the ultrafiltration step tank 40 by the pump 39. The dispersion in the ultrafiltration step tank 40 is introduced into the ultrafiltration module 42 by the pump 41 and subjected to the ultrafiltration step. At this time, the permeated water is measured by the flow meter 43, and the dispersion subjected to ultrafiltration is returned to the ultrafiltration step tank 40. The ultrafiltration step tank 40 is replenished with pure water, and the flow rate is measured by a flow meter 44.

The reaction liquid discharged from the closed mixing means is stored in a product liquid tank as a storage means, and may be directly guided from the tank to an ultrafiltration device as shown in FIGS. As in 3, the liquid may be stored in an ultrafiltration step tank different from the product liquid tank, and then guided to an ultrafiltration device. According to FIG. 3, the product liquid tank can be used as a charging tank, and the ultrafiltration step tank can be used as an aging tank. As a result, the aging time can be shortened due to the temperature rise, and the preparation tank can be washed during the aging to start the next preparation, which leads to an improvement in productivity. In addition, since the resulting particles are not crushed by high stirring, it is possible to provide a high-performance heat-developable image recording material with reduced fog,
Since high agitation is eliminated, bubbles are reduced and the filtration speed in ultrafiltration can be improved.

The closed mixing means constituting the apparatus of the present invention comprises:
The details are not particularly limited as long as it is a closed type. As the closed mixing means used in the present invention, for example, paddle blades, propeller blades, dissolvers, rotary stirrers such as rotary homogenizers, emulsifying and dispersing machines, reciprocating stirrers, static mixers such as static mixers, sludge mixers, etc. Any method such as a mixer or a combination thereof can be used. The closed mixing means may be a single unit, or a plurality of units may be arranged in series or in parallel. When mixing liquids, if the stirring force is too small, sufficient mixing will not be performed. Conversely, if the stirring force is too large, heat generation and cavitation will occur.
For this reason, the stirring power has a preferable range. In the closed mixing means having a rotating blade, the linear velocity at the outermost peripheral portion of the rotating blade is preferably 1 to 50 m / sec, more preferably 1 to 30 m / sec, and the stirring power consumed per unit volume of liquid is preferable. Is 0.1 to 10 KW / L, more preferably 0.5 to 5 KW / L. As a means for suppressing cavitation, a method of reducing dissolved air in the liquid or a method of increasing the pressure with respect to the atmospheric pressure by about 0.1 to ² kgf / cm ² can be adopted.

The material of the closed mixing means is not particularly limited as long as it has appropriate mechanical strength, but a material inert to the silver ion solution, the alkali metal salt solution of the fatty acid and the organic solvent used is preferable. In addition, since the alkali metal salt solution of the fatty acid is usually at a high temperature of 50 ° C. or higher, it is necessary to select a thermally stable material. Stainless steel materials (SUS304, SUS3
16), metal materials coated with titanium or a titanium alloy, glass lining, ceramic, fluororesin, etc.
Composite resin such as glass fiber and Kevlar,
Engineering plastics such as polyacetal and modified polyphenylene oxide;

The closed mixing means constituting the apparatus of the present invention comprises:
One device may be used as in the devices illustrated in FIGS. 1 to 3, or two or more devices may be arranged in parallel. When two or more are arranged in parallel, the solution may be equally supplied to each closed mixing means. As an example of an apparatus using two closed mixing means, FIG.
Can be exemplified. In FIG. 4, a silver ion-containing solution is placed in the additive component 1 tank 45, and an organic acid alkali metal salt-containing solution is placed in the additive component 2 tank 46. Each liquid is pumped 47, 48, 49, 50, respectively.
To the closed mixing means 55, 56. At this time, the flow rate of each liquid is measured and controlled by the flow meters 51, 52, 53, and 54. The respective liquids guided to the closed mixing means 55 and 56 are mixed in the closed mixing means, and the product liquid tank 5
It is led to 7. Part of the liquid in the product liquid tank 57 is re-supplied into the closed mixing means 55, 56 by the circulation pumps 58, 59. A part of the liquid in the product liquid tank 57 is introduced into the ultrafiltration module 61 by the circulation pump 60 for the ultrafiltration step, and is subjected to the ultrafiltration step. At this time, the permeated water is measured by the flow meter 62, and the dispersion subjected to ultrafiltration is returned to the product liquid tank 57. The product liquid tank 57 is replenished with pure water, and the flow rate is measured by the flow meter 63.

In the apparatus of the present invention, the silver ion-containing solution or the organic acid alkali to be supplied to the closed mixing means is used in order to rapidly lower the liquid temperature after the reaction between the silver ion-containing solution and the organic acid alkali metal salt-containing solution. The metal salt-containing liquid can be cooled beforehand. Further, a heat exchanger may be provided between the closed mixing means itself, the closed mixing means and the tank, or before the closed mixing means. There is no limitation on the heat exchanger used for cooling. For example, multi-tube cylindrical heat exchanger, heat pipe type heat exchanger, double tube type heat exchanger, coil type heat exchanger, cascade type heat exchanger, plate type heat exchanger, spiral plate type heat exchanger, water A cold heat exchanger or the like can be used.

As a flow meter for the silver ion-containing solution, an electromagnetic flow meter or a mass flow meter having a measurement error of less than 1% and a time coefficient of less than 1 second can be used. As the flow meter for the organic acid alkali metal salt-containing liquid, a mass flow meter having a measurement error of less than 1% and a time coefficient of less than 1 second can be used. As the pump, a pump (for example, a rotary pump, a sanitary pump, a gear pump, a mono pump, a plunger pump, a diaphragm pump) capable of performing feedback control from the measured value of the flow meter, or a stable discharge with a quantitative error of less than 1% Pumps (for example, gear pumps, mono pumps, plunger pumps, diaphragm pumps) capable of obtaining an amount. Preferably, the pulsation rate is less than 5%.

The heat-developable image recording material which can use the silver salt of an organic acid prepared by the preparation method of the present invention will be further described. The heat-developable image recording material preferably has an image recording layer in which the above-mentioned fatty acid silver salt and a reducing agent for silver ions are dispersed in a binder matrix as a reducible silver salt. To make it photosensitive, a catalytically active amount of a photocatalyst (preferably photosensitive silver halide) is further used.
If necessary, a toning agent for controlling the tone of silver is used.
The organic silver salt can be used in a desired amount, but the silver amount is 0.1%.
-5 g / m ² , more preferably 1-3 g / m ²
m ² .

The reducing agent for silver ions may be any substance (preferably an organic substance) that reduces silver ions to metallic silver. Such a reducing agent is disclosed in JP-A-11-6502.
No. 1, paragraphs 0043 to 0045, and European Patent Publication No. 0803764A1, page 7, line 34 to page 18, page 1.
It is described in two lines. In the present invention, the addition amount of the reducing agent is preferably 0.01 to 5.0 g / m ² ,
The content is more preferably 0.1 to 3.0 g / m ² , and preferably 5 to 50 mol%, more preferably 10 to 40 mol%, per 1 mol of silver on the surface having the image forming layer. Is more preferable. The reducing agent is preferably contained in the image recording layer.

The photosensitive silver halide which can be used in the present invention is not particularly limited in terms of the halogen composition. Can be. The distribution of the halogen composition in the grains may be uniform, the halogen composition may be changed stepwise, or may be changed continuously. Further, silver halide grains having a core / shell structure can be preferably used.

Methods for forming photosensitive silver halide are well known in the art and are described, for example, in Research Disclosure No. 17029, June 1978, and US Pat. No. 3,700,458. Can be used. The addition amount of the photosensitive silver halide is
In terms of the amount of silver applied per m ^{2 of the} thermally developed image recording material,
It is preferably from 0.03 to 0.6 g / m ² ,
More preferably, it is from 0.05 to 0.4 g / m ² ,
Most preferably, it is 0.1 to 0.4 g / m ² .

The binder of the layer containing the organic silver salt may be any polymer, suitable binders being transparent or translucent, generally colorless, natural resins and polymers and copolymers, synthetic resins and polymers and copolymers, Other film-forming media such as gelatins, rubbers, poly (vinyl alcohol) s, hydroxyethyl celluloses, cellulose acetates, cellulose acetate butyrates, poly (vinyl pyrrolidone) s, casein, starch, poly (acrylic) Acids),
Poly (methyl methacrylic acid), Poly (vinyl chloride)
, Poly (methacrylic acid) s, styrene-maleic anhydride copolymers, styrene-acrylonitrile copolymers, styrene-butadiene copolymers, poly (vinyl acetal) s (for example, poly (vinyl formal) and Poly (vinyl butyral)), poly (ester), poly (urethane), phenoxy resin, poly (vinylidene chloride), poly (epoxide), poly (carbonate), poly (vinyl acetate), poly (vinyl acetate) Olefin)
, Cellulose esters and poly (amides).
The binder may be coated from water or an organic solvent or emulsion. Preferably the total amount of the binder in the image-forming layer of the heat developable image recording material is 0.2 to 30 g / m ^2, more preferably 1 to 15 g / m ^2.

Other materials and configurations applicable to the heat-developable image recording material are described in JP-A-10-62899, JP-A-10-268465, and JP-A-11-5.
2509, JP-A-11-352625, JP-A-11-352626, JP-A-11-3526
No. 27, Japanese Unexamined Patent Application Publication No. 11-349591, Japanese Unexamined Patent Application Publication No.
000-7683, JP-A-2000-72711, European Patent Publication No. 0803764A1, European Patent Publication No. 0962812A1, and the like can be referred to.

[0066]

The present invention will be described more specifically below with reference to examples and comparative examples. Materials, usage amounts, ratios, processing contents, processing procedures, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples described below.

Comparative Example 1 (Preparation of Conventional Organic Acid Silver Salt Particle Dispersion A) Behenic Acid (trade name: Edenor C22-85, manufactured by Henkel Co.)
R) 87.6 g, distilled water 423 ml, 5 mol / L aqueous sodium hydroxide solution 49.2 ml, and tert-butanol 120 ml were mixed, stirred at 75 ° C. for 1 hour and reacted to obtain a sodium behenate solution. Separately, silver nitrate 4
206.2 ml (pH 4.0) of a 0.4 g aqueous solution was prepared and kept at 10 ° C. 635ml of distilled water and 30m
The reaction vessel containing 1 l of tert-butanol was kept at 30 ° C., and the whole amount of the sodium behenate solution and the whole amount of the silver nitrate aqueous solution were added at a constant flow rate over 93 minutes and 90 minutes, respectively, with stirring. At this time, only the aqueous solution of silver nitrate is added for 11 minutes after the start of the aqueous solution of silver nitrate, and then the addition of the sodium behenate solution is started. After the completion of the addition of the aqueous solution of silver nitrate, only the sodium behenate solution is added. I did it. At this time, the temperature inside the reaction vessel was set at 30 ° C., and the external temperature was controlled so that the liquid temperature became constant. In addition, the piping for the addition system of the sodium behenate solution should be a double-pipe insulation, and the outer jacket should have 8 pipes.
The liquid temperature at the outlet of the addition nozzle was maintained at 75 ° C. by circulating hot water at 0 ° C. Further, in the piping for the addition system of the silver nitrate aqueous solution, 8 ° C. cold water was circulated through a jacket portion outside the double tube to maintain the liquid temperature at the outlet of the addition nozzle at 10 ° C. The addition position of the sodium behenate solution and the addition position of the silver nitrate aqueous solution were symmetrically arranged around the stirrer, and were set at a height such that they did not come into contact with the reaction solution.

After the addition of the sodium behenate solution is completed,
Stir at the same temperature for 20 minutes, cool to 25 ° C
Was. Then, the solid content is separated by suction filtration, and the solid content is filtered.
Water washing was performed until the water conductivity reached 50 μS / cm. like this
Thus, a silver salt of an organic acid was obtained. The resulting solids should not be dried.
I kept it as a wet cake. Dry solids 100
g wet cake, polyvinyl alcohol
(Product name: PVA-217) 7.4 g and water were added
And make the total amount 385g, then reserve with a homomixer
Dispersed. Next, the pre-dispersed undiluted solution is dispersed in a disperser (trade name:
Microfluidizer M110-S-EH, Micro
Fluidex International Corporation
Pressure of G10Z interaction chamber)
Force 1,750kg / cm ^TwoAnd adjust it three times,
A silver behenate dispersion was obtained. Cooling operation requires a coiled heat exchanger.
Installed before and after the interaction chamber,
Was adjusted to a dispersion temperature of 18 ° C.

<Example 1> (Preparation of Dispersion B of Organic Acid Silver Salt Particles of the Present Invention) Dispersion B was prepared using the equipment shown in FIG. Behenic acid (manufactured by Henkel, trade name: Edenor) in the tank 30
C22-85R) 87.6 g, distilled water 423 ml, te
While stirring 120 ml of rt-butanol at 75 ° C., 5
5 mol / L aqueous sodium hydroxide solution
After adding over a period of minutes, the reaction was carried out for 60 minutes to obtain a sodium behenate solution. Also, silver nitrate 4
206.2 ml of 0.4 g of an aqueous solution (pH 4.0) was prepared and kept at 10 ° C. In addition, 6
Measure 00 ml of pure water, and
Mizuho Industry Co., Ltd. pipeline mixer LR-
Circulated through mold 1 at a flow rate of 100 ml / min. While stirring the pipeline mixer at 10,000 rpm,
Using a pump of No. 33, 2.9 ml /
After a lapse of 5 seconds, a sodium behenate solution was added at a constant flow rate of 9.8 ml / min using a pump 32, and the solution was stored in the tank 38. Here, 2 L of 10 ° C. cooling water is applied to the jacket of the tank 38.
Per minute, the average temperature in the tank was 30 ° C.

After the addition of the sodium behenate solution, 2
The temperature was lowered to 25 ° C. over 0 minutes, and 85 ml of a 4% by mass solution of polyvinyl alcohol (trade name: PVA-217) was used.
Was added. The mixture was left for 20 minutes with stirring. Thereafter, using the pump 39, the obtained liquid containing organic acid silver particles was transferred from the tank 38 to the tank 40, and continuously sent to an ultrafiltration device to perform a desalting treatment. The ultrafiltration device includes a tank 40 for storing the organic acid silver salt particle dispersion,
It basically consists of a circulation pump 41 for supplying the stock dispersion to the ultrafiltration module 42,
It has a flow meter 44 for measuring replenished pure water and a flow meter 43 for measuring permeated water. The membrane module used was a hollow fiber type ACP-1050 manufactured by Asahi Kasei Corporation with a molecular weight cutoff of 13,
000, the flow rate of the solution was 6 l / min, and the pressure difference before and after the module was 1.0 kg / cm ² . At this time, the constant volume dilution ratio was set to 5 times, and thereafter, the replenishment of pure water was stopped. The electric conductivity at this time is 1
It was 00 μS / cm. Thereafter, the mixture was further concentrated to 26% by mass. For the measurement of the solid content concentration, a digital hydrometer DA-300 manufactured by Kyoto Electronics Co., Ltd. was used, and finally, it was verified from the absolute dry mass.

Comparative Example 2 (Preparation of Conventional Organic Acid Silver Salt Particle Dispersion C) Behenic acid (trade name: Edenor C22-85, manufactured by Henkel Co.)
R) 87.6 g, distilled water 423 ml, 5 mol / L aqueous sodium hydroxide solution 49.2 ml, and tert-butanol 120 ml were mixed, stirred at 75 ° C. for 1 hour and reacted to obtain a sodium behenate solution. Separately, silver nitrate 4
206.2 ml (pH 4.0) of a 0.4 g aqueous solution was prepared and kept at 10 ° C. 635ml of distilled water and 30m
The reaction vessel containing 1 l of tert-butanol was kept at 30 ° C., and the whole amount of the sodium behenate solution and the whole amount of the silver nitrate aqueous solution were added at a constant flow rate over 93 minutes and 90 minutes, respectively, with stirring. At this time, only the aqueous solution of silver nitrate is added for 11 minutes after the start of the aqueous solution of silver nitrate, and then the addition of the sodium behenate solution is started. After the completion of the addition of the aqueous solution of silver nitrate, only the sodium behenate solution is added. I did it. At this time, the temperature inside the reaction vessel was set at 30 ° C., and the external temperature was controlled so that the liquid temperature became constant. In addition, the piping for the addition system of the sodium behenate solution should be a double-pipe insulation, and the outer jacket should have 8 pipes.
By circulating hot water of 0 ° C., the liquid temperature at the outlet of the addition nozzle was maintained at 75 ° C. Further, the piping of the addition system of the silver nitrate aqueous solution circulates cold water of 8 ° C. through a jacket portion outside the double tube, and raises the liquid temperature at the outlet of the addition nozzle to 10 ° C.
Maintained. The addition position of the sodium behenate solution and the addition position of the silver nitrate aqueous solution were symmetrically arranged around the stirrer, and were set at a height such that they did not come into contact with the reaction solution.

After the addition of the sodium behenate solution, 2
The temperature was lowered to 25 ° C. over 0 minutes, and 85 ml of a 4% by mass solution of polyvinyl alcohol (trade name: PVA-217) was used.
Was added. The mixture was left for 20 minutes with stirring. The obtained silver salt of an organic acid was continuously fed to an ultrafiltration device in the same manner as in the dispersion B of the silver salt of an organic acid particle to perform a desalting treatment. When the electric conductivity was reduced to 100 .mu.S / cm, stop the replenishment of pure water, but entered the concentration operation, solid concentration 16 wt% filtration at which point the module inlet pressure of dielectric breakdown 3 kgf / cm ² , So that the concentration was completed. For the measurement of the solid content concentration, a digital hydrometer DA-300 manufactured by Kyoto Electronics Co., Ltd. was used, and finally, it was verified from the absolute dry mass.

Example 2 (Preparation of Organic Acid Silver Salt Particle Dispersion D of the Present Invention) Dispersion B was prepared using the equipment shown in FIG. In the tank 16, behenic acid (trade name: Edenor, manufactured by Henkel)
C22-85R) 87.6 g, distilled water 423 ml, te
While stirring 120 ml of rt-butanol at 75 ° C., 5
5 mol / L aqueous sodium hydroxide solution
After adding over a period of minutes, the reaction was carried out for 60 minutes to obtain a sodium behenate solution. In addition, silver nitrate 4
206.2 ml of 0.4 g of an aqueous solution (pH 4.0) was prepared and kept at 10 ° C. In addition, 6
Measure out 00 ml of pure water, and
Mizuho Industry Co., Ltd. pipeline mixer LR-
Circulated through mold 1 at a flow rate of 100 ml / min. While stirring the pipeline mixer at 10,000 rpm,
Using a pump of No. 17, the aqueous solution of silver nitrate was 2.9 ml /
After a lapse of 5 seconds, a sodium behenate solution was added at a constant flow rate of 9.8 ml / min using a pump 18 and stored in the tank 24. After a lapse of 20 minutes, polyvinyl alcohol (trade name: PVA-21)
85 ml of a 4% by weight solution of 7) was added over 10 minutes.
Here, when cooling water of 10 ° C. was supplied to the jacket of the tank 24 at a rate of 2 L / min, the average temperature in the tank was 30 ° C.
° C.

Five minutes after the completion of the addition of the polyvinyl alcohol solution, the solution was continuously fed to an ultrafiltration apparatus to start a desalting treatment. The ultrafiltration device basically comprises a tank 24 for storing the dispersion of organic acid silver salt particles and a circulation pump 25 for supplying the stored dispersion to the ultrafiltration module 26. Flow meter 28 for permeated water measurement. The membrane module used was a hollow fiber type ACP-1050 manufactured by Asahi Kasei Corporation.
Then, constant-volume filtration by replenishing with pure water was performed with the molecular weight cut off being 13,000, the flow rate of the liquid sent being 6 L / min, and the pressure difference before and after the module being 1.0 kg / cm ² . At this time, the constant volume dilution ratio was set to 5 times, and thereafter, the replenishment of pure water was stopped. At this time, the electric conductivity was 100 μS / cm. Thereafter, the mixture was further concentrated to 26% by mass. For the measurement of the solid content concentration, a digital hydrometer DA-300 manufactured by Kyoto Electronics Co., Ltd. was used, and finally, it was verified from the absolute dry mass.

Example 3 (Preparation of Organic Acid Silver Salt Particle Dispersion E of the Present Invention) Except that the polymer dispersant was changed from polyvinyl alcohol to polyvinylpyrrolidone (manufactured by GAF Corporation, trade name: PVPK-30) Prepared an organic acid silver salt particle dispersion E in exactly the same manner as the organic acid silver salt particle dispersion B.

Example 4 (Preparation of Organic Acid Silver Salt Particle Dispersion F of the Present Invention) Except that the polymer dispersant was changed from polyvinyl alcohol to hydroxyethyl cellulose (trade name: SP550, manufactured by Daicel Chemical Industries, Ltd.) Organic acid silver salt particle dispersion E was prepared in exactly the same manner as organic acid silver salt particle dispersion B.

Table 1 summarizes the conditions for preparing organic acid silver salt particle dispersions A to F.

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[Table 1]

Compared with the organic acid silver salt particle dispersion A prepared by the prior art, the organic acid silver salt particle dispersion B prepared by the method of the present invention had finer particles. Since such fine particles can be prepared without going through the complicated steps of suction filtration, washing with water, and dispersion, it was shown that the method of the present invention is a preferable method with high productivity. On the other hand, the organic acid silver salt particle dispersion C prepared by the conventional technique was a dispersion in which primary particles were remarkably aggregated, and the filtration rate in the ultrafiltration performed after the preparation was low. In addition, a dispersion having a predetermined solid content could not be obtained due to an increase in pressure during the concentration operation.
On the other hand, the dispersions of the organic acid silver salt particles DF prepared by the method of the present invention had a high filtration rate, and a dispersion having a desired solid content could be easily obtained.

<Example 5> Preparation of heat-developable image recording material The structure of the compound used is shown below.

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Embedded image

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Embedded image

<< Preparation of Undercoated PET Support >> (Preparation of PET Support) Using terephthalic acid and ethylene glycol, an intrinsic viscosity of 0.66 (phenol-
Polyethylene terephthalate) (measured at 25 ° C. in 6/4 (weight ratio)). This was pelletized, dried at 130 ° C. for 4 hours, melted at 300 ° C., 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 at 110 ° C using rolls having different peripheral speeds, and then 130 ° C using a tenter.
The film was stretched 4.5 times in the transverse direction. Thereafter, after heat-setting at 240 ° C. for 20 seconds, it was relaxed by 4% in the lateral direction at the same temperature. Then, after slitting the chuck portion of the tenter, both ends were subjected to knurling and wound at 4 kg / cm ² to obtain a roll-shaped PET support 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) (1) Preparation of Undercoating Layer Coating Formulation 1 (for the undercoating layer on the photosensitive layer side) Pesresin A-515GB (30% by mass solution) manufactured by Takamatsu Oil Co., Ltd. 234 g Polyethylene glycol mono Nonylphenyl ether (average ethylene oxide number = 8.5) 10% by mass solution 21.5g Soken Chemical Co., Ltd. MP-1000 (polymer fine particles, average particle size 0.4μm) 0.91g distilled water 744ml

Formulation 2 (for the backside first layer) Styrene-butadiene copolymer latex 158 g (solid content 40% by mass, styrene / butadiene weight ratio = 68/32) 2,4-dichloro-6-hydroxy-S- Triazine sodium salt (8% by mass aqueous solution) 20g 1% by mass aqueous solution of sodium laurylbenzenesulfonate 10ml Distilled water 854ml

Formulation 3 (for the second layer on the back surface side) SnO ₂ / SbO (9/1 mass ratio, average particle size 0.038 μm, 17 mass% dispersion) 84 g gelatin (10 mass% aqueous solution) 89.2 g Shin-Etsu Chemical 8.6g, Soken Chemical Co., Ltd., MP-1000 0.01g Sodium dodecylbenzenesulfonate (1% by mass aqueous solution) 10ml NaOH (1% by mass) 6ml Proxel (ICI) 1ml distilled water 805ml

(Preparation of Undercoating Support) Thickness 175 μm
After performing the above-described corona discharge treatment on both surfaces of the biaxially stretched polyethylene terephthalate support, the undercoating coating liquid formulation 1 was coated on one surface (photosensitive layer surface) with a wire bar at a wet application amount of 6.6 ml / m ² (one surface). ) And dried at 180 ° C for 5 minutes. Then, the undercoat coating liquid formulation 2 was applied to the back surface (back surface) with a wire bar so that the wet application amount was 5.7 ml / m ^2. And dried at 180 ° C. for 5 minutes, and the undercoating coating formulation 3 was applied to the back surface (back surface) with a wire bar so that the wet coating amount was 7.7 ml / m ² , and dried at 180 ° C. for 6 minutes. An undercoat support was prepared.

<< Preparation of Back Surface Coating Solution >> (Preparation of Solid Precursor Dispersion (a) of Base Precursor) 64 g of base precursor compound 11 and 2 g of diphenyl sulfone
8 g and 10 g of surfactant Demol N manufactured by Kao Corporation were mixed with 220 ml of distilled water, and the mixture was dispersed in beads using a sand mill (1/4 Gallon Sand Grinder Mill, manufactured by Imex Co., Ltd.) to have an average particle diameter of 0.2. As a result, a solid fine particle dispersion (a) of a base precursor compound having a thickness of μm was obtained.

(Preparation of Dye Solid Fine Particle Dispersion) 9.6 g of cyanine dye compound 13 and 5.8 g of sodium p-dodecylbenzenesulfonate were mixed with 305 ml of distilled water, and the mixture was subjected to a sand mill (1/4 Gallon sand grinder mill, The beads were dispersed using an IMEX Co., Ltd.
A dispersion of solid dye fine particles of 2 μm was obtained.

(Preparation of Anti-Halation Layer Coating Solution) Gelatin 17 g, polyacrylamide 9.6 g, solid fine particle dispersion (a) of the base precursor (70 g), dye solid fine particle dispersion 56 g, single fraction polymethyl methacrylate fine particles (average particle Size 8μm, particle size standard deviation 0.4) 1.5g, benzoisothiazolinone 0.03g, sodium polyethylenesulfonate 2.2g, blue dye compound 14 0.2g, water 844ml,
An antihalation layer coating solution was prepared.

(Preparation of back surface protective layer coating solution)
℃, gelatin 50g, polystyrene sodium sulfonate 0.2g, N, N-ethylenebis (vinylsulfone acetamide) 2.4g, t-octylphenoxyethoxy ethanesulfonic acid sodium 1g, benzoisothiazolinone 30m
g, N-perfluorooctylsulfonyl-N-propylalanine potassium salt 37 mg, polyethylene glycol mono (N-perfluorooctylsulfonyl-N-propyl-2-aminoethyl) ether [average degree of polymerization of ethylene oxide 1
5] 0.15 g, C ₈ F ₁₇ SO ₃ K 32 mg, C ₈ F ₁₇ SO ₂ N (C ₃ H ₇ ) (CH ₂ CH ₂ O) ₄
(CH ₂ ) ₄ -SO ₃ Na 64 mg, acrylic acid / ethyl acrylate copolymer (copolymerization weight ratio 5/95) 8.8 g, aerosol OT
(American Cyanamid Co.) 0.6 g, liquid paraffin emulsion 1.8 g as liquid paraffin, and 950 ml of water were mixed to obtain a back surface protective layer coating solution.

<< Preparation of Silver Halide Emulsion 1 >> Distilled water 1421
Add 3.1 ml of a 1% by weight potassium bromide solution to the
While stirring a solution containing 3.5 ml of sulfuric acid having a mol / L concentration and 31.7 g of phthalated gelatin in a stainless steel reaction bottle, 34 ° C.
The solution A was kept at a temperature of 22.22 g of silver nitrate, and distilled water was added to 22.22 g of silver nitrate to dilute it to 95.4 ml.
Solution B diluted to 4 ml was added at a constant flow rate over 45 seconds. Then, 10 ml of a 3.5% by mass aqueous hydrogen peroxide solution was added.
And then add a 10% by weight aqueous solution of benzimidazole.
10.8 ml was added. Further, a solution C obtained by adding distilled water to 51.86 g of silver nitrate to 317.5 ml and a solution D obtained by diluting 45.8 g of potassium bromide to a volume of 400 ml with distilled water were added at a constant flow rate over 20 minutes. Solution D was added by a controlled double jet method while maintaining pAg at 8.1.
Iridium hexachloride so as to be 1 × 10 ^-4 mol per mol of silver
(III) 10 minutes after the start of adding the solution C and the solution D, the entire amount of the potassium salt of the acid was added. Five seconds after the completion of the addition of the solution C, an aqueous solution of potassium hexairon cyanide (II) was added in a total amount of 3 × 10 ^-4 mol per mol of silver. The pH was adjusted to 3.8 using sulfuric acid at a concentration of 0.5 mol / L, stirring was stopped, and a precipitation / desalting / water washing step was performed. The pH was adjusted to 5.9 with 1 mol / L sodium hydroxide to prepare a silver halide dispersion having a pAg of 8.0.

While stirring the silver halide dispersion, 38
C. and 0.34% by weight of 1,2-benzisothiazoline
5 ml of a methanol solution of -3-one was added, and 40 minutes later, a methanol solution of spectral sensitizing dye A was added at 1 × 10 ^-3 mol per mol of silver, and the temperature was raised to 47 ° C. one minute later. Twenty minutes after the temperature was raised, sodium benzenethiosulfonate was added in an amount of 7.6 × 10 ⁻⁵ mol per mol of silver in a methanol solution, and 5 minutes later, tellurium sensitizer B was added in an amount of 1.9 × 10 ⁻ per mol of silver with a methanol solution. ⁴ mol was added and the mixture was aged for 91 minutes. 1.3 ml of a 0.8% by mass methanol solution of N, N'-dihydroxy-N "-diethylmelamine was added, and after 4 minutes, 5-methyl-2-mercaptobenzimidazole was added with a methanol solution at 3.7 × 10 ⁻ per mol of silver. ³ mol and 1-phenyl-2-heptyl-5-mercapto-1,3,4-triazole in a methanol solution at 4.9 × 10 ⁻³ per mol of silver.
A silver halide emulsion 1 was prepared by molar addition. The grains in the prepared silver halide emulsion had an average sphere equivalent diameter of 0.046.
It was a pure silver bromide particle having a μm and a coefficient of variation of the equivalent sphere diameter of 20%. The particle size and the like were determined from the average of 1000 particles using an electron microscope. The [100] plane ratio of the particles was determined to be 80% using the Kubelka-Munk method.

<< Preparation of Silver Halide Emulsion 2 >> Halogenation
In preparing silver emulsion 1, the liquid temperature at the time of grain formation was changed from 34 ° C to 49 ° C.
To 30 minutes, and the addition time of solution C was changed to 30 minutes.
(II) Halogenation is performed in the same manner except that potassium is removed.
Preparation of silver emulsion 2 was performed. Same as silver halide emulsion 1
Precipitation / desalting / washing / dispersion was performed. Further spectral sensitizing dyes
A was added in an amount of 7.5 × 10^-FourMole, tellurium sensitization
Agent B was added in an amount of 1.1 × 10^-FourMol, 1-phenyl
Ru-2-heptyl-5-mercapto-1,3,4-triazole to silver
3.3 × 10 per mole ^-3Emulsion 1
Similarly, spectral sensitization, chemical sensitization and 5-methyl-2-mer
Captobendiimidazole, 1-phenyl-2-heptyl-5-
Add mercapto-1,3,4-triazole and add halogen
Thus, silver halide emulsion 2 was obtained. Emulsion grains of silver halide emulsion 2
Is the average sphere equivalent diameter of 0.080μm and the coefficient of variation of the sphere equivalent diameter of 20%.
The particles were pure silver bromide cubic particles.

<< Preparation of Silver Halide Emulsion 3 >> In the preparation of silver halide emulsion 1, the liquid temperature of 34 ° C. during grain formation was changed to 27 ° C.
Silver halide emulsion 3 was prepared in the same manner except that the above was changed. Further, as in the case of the silver halide emulsion 1, the precipitation /
Desalting / water washing / dispersion was performed. The spectral sensitizing dye A was added as a solid dispersion (aqueous gelatin solution) in an amount of 6 × 10 ⁻³ mol per mol of silver, and the tellurium sensitizer B was added in an amount of 5.2 × 10 ⁻⁴ per mol of silver.
A silver halide emulsion 3 was obtained in the same manner as in the emulsion 1, except that the mole was changed. The emulsion grains of the silver halide emulsion 3 were pure silver bromide cubic grains having an average sphere equivalent diameter of 0.038 μm and a coefficient of variation in sphere equivalent diameter of 20%.

<< Preparation of Mixed Emulsion A for Coating Solution >> Silver halide emulsion 1 was 70% by mass, silver halide emulsion 2 was 15% by mass,
15% by mass of silver halide emulsion 3 was dissolved and benzothiazolium iodide was dissolved in a 1% by mass aqueous solution at a concentration of 7 × per mole of silver.
10 ^-3 mol was added.

<< Preparation of 25% by Mass Dispersion of Reducing Agent Complex >>
2-methylenebis- (4-ethyl-6-tert-butylphenol)
10 kg of a 1: 1 complex of phenol and triphenylphosphine oxide and denatured polyvinyl alcohol (manufactured by Kuraray Co., Ltd., Poval MP
To 10 kg of the 20% by mass aqueous solution of 203), 16 kg of water was added and mixed well to form a slurry. This slurry was sent by a diaphragm pump and dispersed in a horizontal sand mill (UVM-2: manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm for 3 hours and 30 minutes, and then benzoisothiazolinone sodium salt 0.2 g and water were added to adjust the concentration of the reducing agent to 25% by mass to obtain a reducing agent complex dispersion. The reducing agent complex particles contained in the thus obtained reducing agent complex dispersion had a median diameter of 0.46 μm and a maximum particle diameter of 2.0 μm or less. The obtained reducing agent complex dispersion was filtered through a polypropylene filter having a pore size of 10.0 μm to remove foreign substances such as dust, and stored.

<< Preparation of 10% by Mass Dispersion of Mercapto Compound >> 5 kg of 1-phenyl-2-heptyl-5-mercapto-1,3,4-triazole and modified polyvinyl alcohol (Kuraray)
8.3k of water to 5kg of 20% by weight aqueous solution of Poval MP203 manufactured by
g was added and mixed well to form a slurry. This slurry was sent by a diaphragm pump and filled with zirconia beads having an average diameter of 0.5 mm in a horizontal sand mill (UVM-2:
After dispersing for 6 hours using IMEX Co., Ltd., water was added to adjust the concentration of the mercapto compound to 10% by mass to obtain a mercapto dispersion. The mercapto compound particles contained in the thus obtained mercapto compound dispersion had a median diameter of 0.40 μm and a maximum particle diameter of 2.0 μm or less. The resulting mercapto compound dispersion was filtered through a polypropylene filter having a pore size of 10.0 μm to remove foreign substances such as dust, and stored. Immediately before use, the mixture was again filtered with a polypropylene filter having a pore size of 10 μm.

<< Preparation of 26% by mass dispersion of organic polyhalogen compound-1 >> 5 kg of tribromomethylphenylsulfone
And modified polyvinyl alcohol (Poval MP manufactured by Kuraray Co., Ltd.)
203), 5 kg of a 20% by mass aqueous solution of sodium triisopropylnaphthalenesulfonate, 213 g of a 20% by mass aqueous solution of sodium triisopropylnaphthalenesulfonate, and water
10 kg was added and mixed well to form a slurry. This slurry is sent by a diaphragm pump and has an average diameter of 0.5 mm.
Horizontal sand mill filled with zirconia beads (UVM-
2: Imex Co., Ltd.) for 5 hours, and then 0.2 g of benzoisothiazolinone sodium salt and water were added to adjust the concentration of the organic polyhalogen compound to 26% by mass. A dispersion was obtained. The organic polyhalogen compound particles contained in the organic polyhalogen compound dispersion thus obtained have a median diameter of 0.41 μm and a maximum particle size of
It was 2.0 μm or less. The obtained organic polyhalogen compound dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust, and stored. Also,
After storage, it was stored at 10 ° C or less until use.

<< Preparation of 25% by mass dispersion of organic polyhalogen compound-2 >> 5 kg of tribromomethyl-3-pentanoylaminophenylsulfone and 2.5 kg of a 20% by mass aqueous solution of modified polyvinyl alcohol (Poval MP203 manufactured by Kuraray Co., Ltd.)
Then, 213 g of a 20% by mass aqueous solution of sodium triisopropylnaphthalenesulfonate and 10 kg of water were added, and mixed well to form a slurry. This slurry was sent by a diaphragm pump and dispersed in a horizontal sand mill (UVM-2: manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm for 5 hours, and then 0.2 g of benzoisothiazolinone sodium salt was added. Water was added to adjust the concentration of the organic polyhalogen compound to 25% by mass to obtain an organic polyhalogen compound dispersion. The organic polyhalogen compound particles contained in the organic polyhalogen compound dispersion thus obtained had a median diameter of 0.41 μm and a maximum particle diameter of 2.0 μm or less. The obtained organic polyhalogen compound dispersion was filtered through a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust, and stored.

<< Preparation of 5% by mass solution of phthalazine compound >> 8 kg of modified polyvinyl alcohol MP2 manufactured by Kuraray Co., Ltd.
03 was dissolved in 174.57 kg of water, and then 3.15 kg of a 20% by mass aqueous solution of sodium triisopropylnaphthalenesulfonate.
14.28 kg of a 70% by mass aqueous solution of 6-isopropylphthalazine was added to prepare a 5% by mass solution of 6-isopropylphthalazine.

<< Preparation of 20% by Mass Dispersion of Pigment >>
ent Blue 60 64g and Kao Corporation's Demol N 6.4g water 250
g 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 SBR Latex 40% by Mass >> Ultrafiltration (UF) purified SBR latex was obtained as follows. The following SBR latex was diluted 10 times with distilled water and UF-
Using a purification module FS03-FC-FUY03A1 (Daisen Membrane System Co., Ltd.), dilute and purify until the ionic conductivity becomes 1.5 mS / cm, and Sanyo Chemical Co., Ltd. Sandet-BL
Was added to be 0.22% by mass. NaOH and NH ₄ OH
To adjust the pH to 8.4 by adding Na ⁺ ion: NH ₄ ⁺ ion = 1: 2.3 (molar ratio). The latex concentration at this time was 40% by mass. (SBR latex: -St (71)-
(Bu (26) -AA (3)-latex) Average particle size 0.1μm, Concentration 45% by mass, Equilibrium moisture content at 25 ° C 60% RH 0.6% by mass, Ion conductivity 4.2mS / cm (Ion conductivity measurement Uses a conductivity meter CM-30S manufactured by Toa Denpa Kogyo Co., Ltd.
Latex stock solution (40% by mass measured at 25 ° C), pH 8.2

<< Preparation of Coating Solution for Image Forming Layer >> Examples 1-4
103 g of each organic acid silver salt particle dispersion prepared in the above, 20 mass of pigment
% Aqueous dispersion 1.1 g, polyvinyl alcohol PVA-205 (Kuraray
5 g of a 20% by mass aqueous solution of
% Dispersion 26g, organic polyhalogen compound dispersion-1, -2
3 (weight ratio), total amount 8.2g, Mercapto compound 10% dispersion
6.2g, ultrafiltration (UF) purified and pH adjusted SBR latex
(Tg: 24 ° C.) 106 g of 40 mass%, 5 mass of phthalazine compound
Add 18 ml of a solution containing
Forming layer (photosensitive layer, emulsion
Layer) 70ml / m of coating solution as it is to coating die ^TwoTona
And applied. Viscosity of the image forming layer coating solution
The temperature was measured with a B-type viscometer of Tokyo Keiki, and was measured at 40 ° C (No.
At 60 rpm) was 85 [mPa · s]. Rheometric
RFS Fluid Spectro manufactured by Far East Co., Ltd.
The viscosity of the coating solution at 25 ° C using a meter
1500, 2 at 0.1, 1, 10, 100, 1000 [1 / sec]
The values were 20, 70, 40 and 20 [mPa · s].

<< Preparation of Coating Solution for Intermediate Layer on Image-Forming Layer >> 772 g of 10% by weight aqueous solution of polyvinyl alcohol PVA-205 (manufactured by Kuraray Co., Ltd.), 5.3 g of 20% by mass dispersion of pigment, methyl methacrylate / styrene / butyl acrylate / Hydroxyethyl methacrylate / acrylic acid copolymer (copolymer weight ratio 64
/ 9/20/5/2) Aerosol in 226 g of latex 27.5% by mass liquid
2m of 5% by mass aqueous solution of OT (American Cyanamid)
l, 10.5m of 20% by mass aqueous solution of diammonium phthalate
l, water was added so that the total amount of 880 g, an intermediate layer coating liquid was prepared with NaOH to pH 7.5, was fed to a coating die to provide 10 ml / m ^2. The viscosity of the coating solution was 21 mPa · s using a B-type viscometer at 40 ° C. (No. 1 rotor, 60 rpm).

<< Preparation of Coating Solution for First Layer of Image Forming Layer Surface Protective Layer >> Inert gelatin (64 g) was dissolved in water, and methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (copolymer weight ratio 64 / 9/20/5/2) 80g of latex 27.5% by weight liquid, 23ml of 10% by weight methanol solution of phthalic acid, 23ml of 4-methylphthalic acid
23 ml of 10 mass% aqueous solution, 28 ml of 0.5 mol / L sulfuric acid, 5 mass% of Aerosol OT (American Cyanamid)
5 ml of an aqueous solution, 0.5 g of phenoxyethanol and 0.1 g of benzoisothiazolinone were added, and water was added to make a total amount of 750 g to prepare a coating solution. A mixture of 26 ml of 4% by mass chrome alum was mixed with a static mixer immediately before coating. 18.6ml / m
^The solution was fed to the coating die so as to be ² . The viscosity of the coating solution was 17 mPa with a B-type viscometer at 40 ° C (No. 1 rotor, 60 rpm).
[S].

<< Preparation of Coating Solution for Second Layer of Image Forming Layer Surface Protective Layer >> 80 g of inert gelatin was dissolved in water, and a methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (copolymer weight ratio 64 / 9/20/5/2) 102 g of a latex 27.5% by mass liquid, 3.2 ml of a 5% by mass solution of N-perfluorooctylsulfonyl-N-propylalanine potassium salt, polyethylene glycol mono (N-perfluorooctylsulfonyl-N- Propyl
32 ml of a 2% by weight aqueous solution of 2-aminoethyl) ether [average degree of polymerization of ethylene oxide = 15], 23 ml of a 5% by weight solution of aerosol OT (manufactured by American Cyanamid Co., Ltd.), polymethyl methacrylate fine particles (average particle diameter) 0.7 μm) 4 g, polymethyl methacrylate fine particles (average particle size 4.5 μm) 21 g, 4-g
1.6 g of methylphthalic acid, 4.8 g of phthalic acid, 44 ml of sulfuric acid at a concentration of 0.5 mol / L, and 10 mg of benzoisothiazolinone were added with water to a total amount of 650 g.
Immediately before coating, 445 ml of an aqueous solution containing 7% by mass of phthalic acid was mixed with a static mixer to obtain a surface protective layer coating solution, which was then sent to a coating die at 8.3 ml / m ² . The viscosity of the coating solution is 40 ° C with a B-type viscometer (No.1 rotor, 60 rp.
m) was 9 [mPa · s].

<< Preparation of heat-developable image recording material >> On the back surface side of the undercoating support, an antihalation layer coating solution was applied so that the coating amount of the solid fine particle dye was 0.04 g / m ² .
The coating amount of the back surface protective layer was 1.7 g / m ² of gelatin.
And then dried to form a back layer. Image forming layer from undercoat on the side opposite to the back side
(Silver halide applied silver amount 0.14 g / m ² ), intermediate layer, protective layer first layer, protective layer second layer in the order of slide bead coating method and simultaneously multi-layer coating, sample of heat-developable image recording material It was created. The coating and drying conditions are as follows. The coating was performed at a speed of 160 m / min, the gap between the coating die tip and the support was set to 0.10 to 0.30 mm, and the pressure in the decompression chamber was set to be 196 to 882 Pa lower than the atmospheric pressure. The support was neutralized with ion wind before coating. Dry-bulb temperature in subsequent chilling zone
After cooling the coating liquid with a wind of 10 to 20 ° C, it is transported in a non-contact type, and a dry bulb temperature of 23 to 45 is provided by a helix type non-contact drying device.
It dried with the dry wind of 15 degreeC, and a wet bulb temperature of 15-21 degreeC. After drying,
After humidity control at 25 ° C and relative humidity of 40-60%, the film surface is 70-90 ° C.
Was heated to become. After heating, the film surface was cooled to 25 ° C. The resulting heat-developable image recording material had a matte degree of Beck smoothness of 550 seconds on the photosensitive layer side and 130 seconds on the back side. When the pH of the film surface on the photosensitive layer surface side was measured, it was 6.0.
Met.

<< Evaluation of heat-developable image recording material >>
4 and the coated surface state of the image forming layer of the heat-developable image recording material produced using each of the organic acid silver salt particle dispersions prepared in Comparative Examples 1 and 2 was visually evaluated. As a result, the heat-developable image recording materials using the respective organic acid silver salt particle dispersions prepared in Examples 1 to 4 had extremely good coated surface conditions.

[0111]

According to the method of the present invention, the reacted organic acid silver salt is removed as a solid, and unnecessary inorganic salts produced by the reaction and the organic solvent used in the reaction are efficiently removed without being dispersed again. be able to. For this reason, according to the method of the present invention, the productivity of organic acid silver salt particles can be significantly improved. Further, according to the method and the preparation apparatus of the present invention, the installation space can be significantly reduced and the equipment cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view showing one configuration example of an apparatus used for preparing an organic acid silver salt according to the present invention.

FIG. 2 is a schematic view showing another configuration example of an apparatus used for preparing the organic acid silver salt of the present invention.

FIG. 3 is a schematic view showing still another configuration example of an apparatus used for preparing the organic acid silver salt of the present invention.

FIG. 4 is a schematic view showing still another configuration example of an apparatus used for preparing the organic acid silver salt of the present invention.

[Explanation of symbols]

 1, 15, 29, 45 Additive 1 tank 2, 16, 30, 46 Additive 2 tank 3 Additive 3 tank 4, 17, 31, 47, 48 Additive 1 pump 5, 18, 32, 49, 50 Pump for additive component 2, 6, 21, 35, 58, 59 Pump for additive component 3, 7, 19, 33, 51, 52 Flow meter for additive component 1, 8, 20, 34, 53, 54 For additive component 2 Flow meter 9, 22, 36 Flow meter for additive component 3, 10, 23, 37, 55, 56 Closed mixing means 11, 24, 38, 57 Product liquid tank 12, 25, 41, 60 Pump for ultrafiltration process circulation 13, 26, 42, 61 Ultrafiltration module 14, 27, 43, 62 Flow meter for permeated water measurement 21, 35, 58, 59 Pump for circulation 28, 44, 63 Flow meter for replenishment water measurement 39 Pump for liquid transfer 40 limit Tank for over-process

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[Procedure amendment]

[Submission date] September 13, 2000 (2009.1)
3)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

The organic acid constituting the organic acid alkali metal salt-containing liquid used in the present invention is relatively stable to light when a silver salt is used, but is exposed to a photocatalyst (a photosensitive silver halide). Latent image) and 80 in the presence of a reducing agent.
It is selected from those which form a silver image when heated to ℃ or more. As organic acids, especially those having 10 carbon atoms
It is preferred to use long-chain fatty carboxylic acids of ~ 30, preferably 15-28. Specifically, cellotic 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, tartaric acid, linoleic acid, butyric acid Preferably, behenic acid, arachidic acid, stearic acid, oleic acid, lauric acid, caproic acid, myristic acid, palmitic acid, and mixtures thereof are used. Examples of the alkali metal constituting the organic acid alkali metal salt-containing liquid used in the present invention include sodium and potassium. The alkali metal salt of an organic acid can be prepared by adding sodium hydroxide, potassium hydroxide, or the like to the organic acid. At this time, it is preferable that the amount of the alkali is made equal to or less than the equivalent of the organic acid so that the unreacted organic acid remains. In this case, the amount of the residual organic acid is 3 to 50 mol with respect to all the organic acids.
1%, more preferably 3 to 30 mol%. 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 excess alkali.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0076

[Correction method] Change

[Correction contents]

Example 4 (Preparation of Organic Acid Silver Salt Particle Dispersion F of the Present Invention) A polymer dispersant was changed from polyvinyl alcohol to hydroxyethyl cellulose (trade name: SP550, manufactured by Daicel Chemical Industries, Ltd.). An organic acid silver salt particle dispersion F was prepared in exactly the same manner as the organic acid silver salt particle dispersion B.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) // B01F 17/32 B01F 17/32 17/38 17/38 17/52 17/52 F term (reference) 2H123 AB00 AB03 AB23 BC00 BC12 CB00 CB03 4D006 GA06 HA01 HA21 HA41 HA61 KA01 KA03 KB13 KD04 KE15Q KE15R KE19Q KE19R KE30R MA01 MA02 MA03 MA04 MB05 MC39 MC62 PA01 PB12 PB15 PC01 4D077 AA06 AC05 BA02 BA07 DEXA DDX03A03X03 DE03 DEX3

Claims (9)

[Claims] 1. A solution containing a silver ion in water or a mixture of water and an organic solvent, and a solution containing an alkali metal salt of an organic acid in water, an organic solvent, or a mixture of water and an organic solvent. Alternatively, in the method of preparing organic acid silver salt particles by reacting with a suspension containing an organic acid alkali metal salt-containing liquid, the silver ion-containing solution and the organic acid alkali metal salt-containing liquid are mixed in a closed mixing means. To mix and react,
A method for preparing organic acid silver salt particles, comprising a step of removing by-product salts contained in a reaction solution by using an ultrafiltration membrane in parallel with or after the reaction. 2. At least a part of a mixture obtained after reacting the silver ion-containing solution and the organic acid alkali metal salt-containing solution mixed in the closed mixing means is circulated to the closed mixing means. The method for preparing organic acid silver salt particles according to claim 1, wherein the silver salt is added. 3. The method according to claim 1, wherein at least one kind of dispersant is added before the start of the reaction and before the purification using the ultrafiltration membrane is completed. Preparation method of organic acid silver salt particles. 4. The organic material according to claim 3, wherein at least a nonionic polymer dispersant having a molecular weight of 5 to 50 times the molecular weight cut off of the ultrafiltration membrane is used as the dispersant. Preparation method of silver acid salt particles. 5. The method for preparing silver salt of organic acid according to claim 4, wherein the concentration of the nonionic polymer dispersant is 0.1 to 30% by mass of the solid content of silver organic acid. . 6. The organic acid silver salt particles according to claim 3, wherein at least one of polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, and hydroxypropyl cellulose is used as the dispersant. Preparation method. 7. After removing the by-product salt by ultrafiltration at a constant volume of 2 to 20 times, the dispersion concentration is adjusted to 10 to 5 times.
The method for preparing organic acid silver particles according to any one of claims 1 to 6, wherein the concentration is reduced to 0% by mass. 8. A first supply unit for supplying a silver ion-containing solution containing silver ions in water or a mixture of water and an organic solvent to a closed mixing unit; water, an organic solvent, or a mixture of water and an organic solvent. Second supply means for supplying a solution or suspension containing an organic acid alkali metal salt therein to the closed mixing means; water or a mixture of water and an organic solvent to the closed mixing means; Third supply means for supplying; closed mixing means for mixing the supplies from the first supply means, the second supply means, and the third supply means to generate a liquid containing organic acid silver salt particles; Storage means for discharging and storing the liquid containing silver salt of acid salt from the closed mixing means; fourth supply means for supplying the liquid containing organic acid silver salt particles in the storage means from the storage means to the ultrafiltration step; By-product salts are limited from particle-containing liquid An apparatus for preparing organic acid silver salt particles, comprising: a purification means for removing by filtration. 9. A first supply unit for supplying a silver ion-containing solution containing silver ions in water or a mixture of water and an organic solvent to a closed mixing unit; water, an organic solvent, or a mixture of water and an organic solvent. Second supply means for supplying a solution or suspension containing an organic acid alkali metal salt therein to the closed mixing means; a first supply means, a second supply means, and a third supply means Closed mixing means for mixing the feed from the supply means to produce a liquid containing organic acid silver salt particles;
Storing means for discharging and storing the generated organic acid silver salt particle-containing liquid from the closed mixing means; third supply means for re-supplying at least a part of the generated organic acid silver salt particle-containing liquid to the closed mixing means Fourth supply means for supplying the organic acid silver salt particle-containing liquid in the storage means from the storage means to the ultrafiltration step; and purification means for removing by-product salts from the organic acid silver salt particle-containing liquid by ultrafiltration; An apparatus for preparing organic acid silver salt particles, comprising: