JP2687180B2 - Method for producing silver halide emulsion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a silver halide (hereinafter referred to as AgX) for a photographic light-sensitive material.
The present invention relates to a method for producing an emulsion, and particularly to a method for producing the AgX emulsion grains with good reproducibility and in a large amount.

(Prior Art) Usually, if an AgX emulsion with excellent performance can be developed in a small-volume reactor for research (usually having a volume of 1 to 5 l),
In order to put the emulsion into practical use, the production scale of the emulsion is then scaled up to a medium volume (usually in a reaction vessel of 10 to 150 l). Once the emulsion of the desired performance can be produced in the medium volume reaction vessel, it is necessary to scale up the production scale of the emulsion to a large volume (usually 200 to 2000 liters). When the emulsion is produced according to the same production procedure, the performance of the AgX emulsion produced in the small-capacity reactor and the performance of the AgX emulsion produced in the medium-capacity reactor often agree within an allowable range, but the large-capacity Often does not match the performance of AgX emulsions produced in the Reactor. Therefore, in the case of mass production, it is often the case that a part of the production procedure is modified to match the performances of both. This work is expensive and time consuming.

This is because the conventional AgX emulsion manufacturing method has been mainly performed by the following method. Nucleation → (aging) → crystal growth is performed in the same reaction vessel. Most conventional AgX emulsion production has been carried out by this method. It may or may not go through the aging process. After seeding,
A method in which a part of the seed crystal is divided and taken out, and put into a reaction vessel for crystal growth. For example, in Example 1 of U.S. Pat. No. 4,067,739, seed crystals are formed by the steps of nucleation → ripening → emulsion water washing, a part of the seed crystals is taken out, and then the seed crystals are grown. In Examples 7 to 11 of U.S. Pat. No. 4,797,354, after the nucleation, a part of the nuclei is taken out, and an aging → crystal growth step is performed to produce an AgX emulsion. However, all of them were carried out in a reaction container of the same level capacity, and the reaction container capacities of the nucleation process and the crystal growth process were not used separately. Further, it is a system in which a part of the nucleation or seed formation emulsion is taken out.

Further, a problem in a large-scale apparatus is mainly that the silver salt aqueous solution and the halide salt aqueous solution to be added are added in a thick flux, but no measures have been taken against this.

(Problems to be Solved by the Invention) The present invention provides a method for mass-producing an AgX emulsion that solves the above problems.

That is, an object of the present invention is to provide a mass production method of an AgX emulsion, which can easily produce an AgX emulsion having the same performance as an AgX emulsion produced by a small-capacity reaction apparatus, and can reproducibly produce a large amount in a large-scale apparatus. is there.

(Means for Solving the Problems) The object of the present invention is: (1) In a method for producing a silver halide emulsion having at least a dispersion medium and silver halide grains, the nucleation of the grains is carried out in a medium volume batch system or Performed in a multi-stage batch type reaction device (hereinafter, medium amount device), and transfer the produced nuclear emulsion to a mass production device (hereinafter, large amount device) or transfer the nuclear emulsion to an intermediate container and then to a mass production device. Then, aging and / or crystal growth is performed in the mass production apparatus, (volume of the mass production apparatus / volume of the medium volume apparatus) = y is 3 to 2000, and the number of times (n) of the liquid transfer is 2 to 2000. A method for producing a silver halide emulsion, characterized in that the number of times is one.

(2) The medium volume device has a capacity of 5 to 500 liters, and the y
The method for producing a silver halide emulsion according to the above (1), wherein the value is 3 to 400 and the n value is 3 to 400.

(3) Using 2 to 30 of the medium-capacity reactors, keeping the temperature of the intermediate container at 10 to 45 ° C., and keeping the temperature of the large-volume reactor at 40.
The method for producing a silver halide emulsion according to the above (1), characterized in that the method is maintained at -80 ° C.

(4) The y value is 3 to 50, the n value is 3 to 20,
In addition, the nucleation is performed by an equilibrium simultaneous mixing method of an aqueous solution of a silver salt and a halide salt, and the equilibrium simultaneous mixing is performed by a flow rate controlling method without using a silver potential controlling method. ) A method for producing a silver halide emulsion.

(5) The addition of the aqueous silver salt solution and the aqueous halide salt solution during the nucleation and crystal growth is performed through a porous body having four or more pores per one added solution.
Of producing a silver halide emulsion.

(6) The above silver halide emulsion is characterized in that 70% or more of the total projected area of the silver halide grains is composed of tabular silver halide grains having parallel twin planes.
Of silver halide emulsion.

(Basic concept of the present invention) When the production scale of an AgX emulsion is scaled up from a small scale to a large scale, the performances of the two often do not match. The main cause is considered to be the nucleation process. Usually, the nucleation period of AgX particles is often 1/10 or less of the total grain formation period. In particular, it is 1/30 to 1/300 for high-sensitivity tabular grains having parallel twin planes. Therefore, there is a relationship of (time for nucleation to be carried out n times with a medium-volume apparatus and n times of nuclei emulsion accumulation) <(aging → crystal growth time). Therefore, the problem is solved by performing nucleation n times in a medium-weight apparatus, accumulating n times of nuclei emulsion, then transferring the accumulated emulsion to a large-scale apparatus, and performing ripening → crystal growth. The accumulated emulsion can be stored in a refrigerator or the like, but it has a problem of storage stability of the emulsion and a problem of increasing the number of steps such as redissolution. Therefore, it is more preferable to accumulate the emulsion in an intermediate container provided beside the large-scale apparatus and immediately transfer the emulsion to the large-scale apparatus. The temperature of the intermediate container is preferably kept low. On the other hand, according to our research, the problem in the large-scale apparatus is that the silver salt aqueous solution and the halide salt aqueous solution to be added are mainly added in a thick flux. Therefore, the problem was solved by adding through a porous body. Furthermore, the problem was solved by adding ultrafine particle AgX prepared in advance.

(Detailed Description) The AgX emulsion production recipe to which the method of the present invention is applied is (ripening and / or crystal growth period) / (nucleation period) = x ≧ 5,
More preferably, x is a formulation of 10 to 300.

The medium amount device and the large amount device in the present invention have a relation of y = (large amount device capacity / medium amount device capacity) ≧ 3, preferably 5 to 50. Medium volume device capacity is 5-500 l, more preferably 30-
200 l, mass device capacity is 200 l or more, preferably 500
It is up to 2000 l, and the capacity can be appropriately selected according to the above relationship. The term "intermediate container" as used in the present invention refers to a container having a capacity capable of accommodating the n times of the nuclear emulsion, and usually 100 l
Above, preferably refers to a 200-1000l container.

The process of producing an AgX emulsion using the method of the present invention comprises a nucleation process, a ripening process and / or a crystal growth process, and the formation of new stable nuclei ends within the nucleation process. Substantially no new stable nuclei are formed during the aging and / or crystal growth process. The term "substantially" as used herein means that
It refers to 20% or less, preferably 10% or less, of the total projected area of AgX grains.

The apparatus of the present invention will be described below in detail along with each manufacturing process (nucleation, ripening, growth) of an AgX emulsion.

Nucleation Process In the present invention, the nucleation process of AgX emulsion grains is carried out in a medium-weight apparatus for the following reason.

The process that requires the most precise control of supersaturation in AgX grain formation is the nucleation process. The reason is as follows. Once defects such as twin planes and dislocation lines are incorporated into the crystal in the nucleation step, they do not disappear in the subsequent crystal growth process, and normally, those twin planes and dislocation lines are also
It grows with crystal growth. And finally obtained Ag
The formation and properties of X particles are affected by these defects.
For example, E.Klein.HJMetz, E.Moisar, for the relationship between the number of twin planes per grain and the way twin planes enter and the grain shape,
Phot.Korr., 99 , 99-102 (1963), 100 , 57-71 (1
964) can be referred to.

Therefore, in order to make AgX particles with the desired shape and properties, it is important to control various supersaturation factors precisely at the time of nucleation and to control the number of those defects incorporated in the generated nuclei. . For example, in order to form a monodisperse hexagonal tabular AgX emulsion grain (hexagonal tabular grain having two twin planes parallel to each other in one AgX grain), various twin crystal plane formation probabilities during nucleation are controlled. Supersaturation factor of (eg,
It is necessary to adjust the Br concentration, the gelatine concentration, etc. in the reaction solution so as not to be too high and not too low so as to increase the probability that two twin planes are incorporated per grain. When the solute addition is continued under the same conditions for 0 to 4 minutes with respect to the nucleation period, the ratio of (twin crystal number / grain) increases as the period becomes longer. It is necessary to control including the formation period.

For details of these, Japanese Patent Application No. 63-315741 and Japanese Unexamined Patent Publication No.
The description in 3-92942 can be referred to. In order to produce defect-free grains (AgX grains that do not contain twin planes or dislocation lines), various supersaturation conditions are controlled to be as low as possible during nucleation, and twin planes and dislocation lines are not contained. It is necessary to make different nuclei. For details, refer to Japanese Patent Application No. 63-223.
The description of No. 739 can be referred to. In order to precisely control the degree of supersaturation during nucleation, the reaction vessel preferably has a small volume. This is because the reaction solution circulates frequently in the reaction vessel, and thus the added AgNO ₃ aqueous solution and the halide salt aqueous solution are more rapidly and uniformly mixed in the entire reaction solution.

Usually, the modification studies of AgX emulsions are carried out in 1-5 liter small containers. Stable core made with this small-volume manufacturing device, or about
If a stable nucleus made with a medium-volume manufacturing device with a capacity of 50 times or less is used as it is for mass production, the most important step of AgX particle formation is the same or almost the same, so it is produced with a small-volume manufacturing device. It is possible to better match the performance of the AgX emulsion produced with the AgX emulsion produced by the mass production equipment.

Usually, the stable nucleation period of AgX particles is about 5 seconds to 10 minutes, which is considerably shorter than the total process period. In particular, in the case of producing tabular emulsion grains, the size of the nucleus is preferably small because the degree of supersaturation at the time of nucleation is high and many stable nuclei are generated, and the ripening process proceeds rapidly next. Therefore, the nucleation period is usually about 5 seconds to 2 minutes, which is very short. In such a case, a long time is not required even if the nucleation is performed by a medium-volume apparatus and the reaction solution is transferred to an intermediate container many times. Therefore, the method of this invention is particularly suitable for making tabular emulsion grains.

Next, the medium amount device for nucleation and the relationship between the medium amount device and the large amount device according to the present invention will be described in detail. The mode of the medium-weight apparatus can be classified into the following two types of batch type and multi-stage batch type.

1) Batch type. Nucleate with a medium-volume apparatus, and when the nucleation is completed, the reaction solution is transferred to an intermediate container. If the capacity of the medium capacity device is 1 / n of the capacity of the large capacity device, this operation is repeated n times. This means that n-fold amount of nuclei that were almost the same as when they were prepared with the medium-volume device could be prepared. That is, as shown in FIG. 1, one intermediate container is installed between the medium quantity devices. While aging and / or crystal growth is performed in a large-scale apparatus, the n-th nucleation is performed in a medium-weight apparatus, and the reaction vessel after the nucleation is stored in the intermediate vessel. After the reaction in the large-scale apparatus is completed, the apparatus is emptied, and the cleaning is completed, the reaction solution in the intermediate container is transferred to the large-scale apparatus. Then, the reaction is started with a large-scale apparatus. In this case, there is an advantage that the waiting time during nucleation can be almost eliminated by installing only one intermediate container. As the gelatin aqueous solution added to the container at the time of nucleation, it is preferable to add a solution that has been previously thermostated to the nucleation temperature. This is because the nucleation can be repeated rapidly.

In addition, the following description can be referred to in order to carry out the step more effectively.

The number of n is reduced. That is, the capacity of the medium weight device is increased within a range in which an AgX emulsion having the same characteristics as the emulsion made by the research small amount device can be prepared. Usually, even if the volume of the reaction vessel is increased up to about 100 l, the AgX emulsion having the same characteristics can be easily prepared. Therefore, in the present invention, the value of n can take a value of 2 or more, but preferably 3 to
The value is 30, more preferably 5 to 20. Note that the maximum value of n is n = (mass device capacity / small research device capacity). This is because making the capacity of the medium-volume device smaller than the capacity of the research small-volume device has no merit only by increasing n and increasing the number of operations. Also, if the minimum value of n is less than 2, the capacity of the small amount device becomes too large, and the effect of the present invention becomes small, which is not preferable.

Two or more of the medium weight devices are used. The use of two identical medium weight devices reduces the number of nucleation operations to n / 2, and the use of m identical medium weight devices reduces the number of nucleation operations to n / m. The value of m is preferably 1 to 30, more preferably 1 to 10. This is because the larger the value of m, the shorter the nucleation time, but the more equipment and the higher the manufacturing cost.

2) Multi-stage batch system. The nucleation step as shown in FIG.
In each stage, nucleation is performed for about 1 / l of each formation period t. FIG. 2 shows only the medium weight device section. It is preferable that the medium quantity devices of A and B are the same. The operating procedure is as follows. Put the reaction solution in the container of A and
Nucleate for t / 2 hours. After that, the solution is transferred to a container B, and a new reaction solution is put into A. Next, nucleation is performed on A and B for about t / 2 hours each. After that, the solution of B is transferred to the intermediate container, the solution of A is transferred to the solution B, and a new reaction solution is added to A. After that, it is repeated in order until the predetermined amount of AgX emulsion is accumulated in the intermediate container. In each step, for example, the solution B is transferred to an intermediate container and the solution A is added to the solution B
The nucleation reaction of B may be started at the time of transfer to the solution,
It goes without saying that it is not necessary to have the start of the reaction until the reaction solution is set in A as well.

Compared with the case described in the above item 1), there is an advantage that a cleaning step in the middle is unnecessary. For example, when the A is used as an independent medium amount device, the size of the stable nucleus after the nucleation is the size of the final nucleus. When the solution remains in the container A after the transfer of the solution, the remaining stable nuclei grow larger in the next nucleation step, and the difference from the size of newly generated stable nuclei becomes large. When the size of the stable nuclei is large, this difference becomes large, and large nuclei are mixed in. Therefore, in that case, it is necessary to insert a washing step for each nucleation. However, in the case of FIG. 2, since the nucleation time in A is t / 2, the size of the nucleus after nucleation is smaller than the size of the finally obtained nucleus.
Therefore, even if only a small amount of the solution remains in A after transferring the solution to B, the influence on the size distribution is small. The larger the value of l, the smaller the effect. Therefore, there is no need to insert a washing process for each container in the middle. This method is effective for formulations in which the nucleation period is 1 minute or longer, preferably 2 minutes or longer. When applied to a formulation with a nucleation period of 1 minute or less, the ratio of the transfer time of the solution from A to B and from B to a large-scale device increases with respect to the nucleation period, which is not advantageous.
Therefore, the upper limit of l is preferably t / l ≧ 30 seconds. Also in this case, two or more multi-stage batch systems as shown in FIG. 2 can be installed. Normally, 10 systems or less are preferable. This is because the nucleation period is shortened as the number of the systems is increased, but the equipment cost is increased.

Another example of the multi-stage batch system is the one shown in FIG. FIG. 3 (I) is a side view and (II) is a top view. In this case, the liquid delivery pipe is eliminated, and the inclined container side walls (a, b) and the container bottom also serve as the role. It has the advantages that there is no residual liquid in the liquid delivery pipe and that liquid can be delivered quickly. The operation procedure is the same as in the case of FIG. A method of opening and closing the liquid transfer by raising and lowering a and b, or by taking them in and out in the lateral direction may be used, and the side walls (a and b)
A system in which an opening / closing valve is provided in the lower part of may be used.

In the present invention, the respective advantages of 1) to 2) above,
In view of the drawbacks, they can be used alone or in combination according to their respective purposes. For example, the method of the present invention is particularly advantageous as a mass production apparatus for monodisperse tabular emulsion grains, but in this case, the nucleation period is usually 3 minutes or less and short. Therefore, in such a case, the method 1) is most preferable in that the (transfer time / nucleation time) can be shortened and the apparatus is simple.

Next, other preferable embodiments relating to the above apparatus and operating conditions will be further described. In FIG. 1, transfer of liquid from the medium-volume device to the intermediate container or the large-volume device is performed by opening the valve at the bottom of the medium-volume device container and transferring the liquid by natural gravity, which is the simplest and cheapest method. Is preferred. First
In the case of the cascade method as shown in the figure, it can be easily installed by using the slope of the mountain or oka. In addition to the method for transferring the solution, it is also possible to transfer the solution using a pump. Each device is placed on the same floor and can be preferably used when natural gravity cannot be used. In addition, after transferring the solution, a step of washing the medium-volume device and the liquid supply pipe can be added at any time. Needless to say, in order to shorten the liquid feeding time, the inner diameter of the liquid feeding pipe may be increased and the length may be shortened as much as possible.

It is not preferable that the nuclei undergo physical aging in the intermediate container while nucleation is performed by this medium-volume apparatus and the operation of transferring the reaction solution to the intermediate container is repeated n times. Therefore, it is preferred to keep the temperature of the reaction solution low during storage to prevent changes during storage of the nuclei. The preferred storage temperature is 10 to 45 ° C, more preferably 15 to 40 ° C. The solution can also be stirred to keep the temperature constant. When the intermediate container is installed as described in 1), there are the following advantages in this respect. In tabular grain formation, the temperature is raised and physical ripening is carried out after nucleation. Therefore, in the absence of the intermediate container, the bulk device must be cooled to a low temperature and then heated. However, when the intermediate container is provided, it is sufficient to keep the intermediate container at a low temperature at all times, and the temperature raising process is not always necessary. That is, the large-scale device can start from a high temperature state immediately after the liquid transfer. Therefore, there are advantages in terms of energy saving and quickness. Generally, the temperature of the bulk device is maintained above 40 ° C, preferably 50-80 ° C.

The liquid contact part of the small amount device is preferably made of a material having a contact angle with water of> 90 ° (for example, Teflon or a surface-coated Teflon). This is because the interaction between the reaction solution and the wall of the container is small, so that the amount of residual solution for liquid transfer can be reduced. It is preferable that the liquid contact portion is made of Teflon or a material coated with Teflon from the viewpoint of acid resistance, alkali resistance, and prevention of impurity metal contamination.

The conventional apparatus usually performs nucleation reaction to crystal growth in one reaction vessel. Therefore, the amount of reaction solution at the time of nucleation is often suppressed to 1/3 or less of the capacity of the container. in this case,
When vigorously stirred, the reaction solution becomes full of bubbles and conversely the stirring efficiency deteriorates. However, since the medium-volume apparatus of the present invention is dedicated to nucleation, it is not necessary to leave a space for crystal growth. Therefore, since the reaction solution amount at the time of nucleation can be increased and used, the mixture can be more vigorously stirred and mixed, and uniform nucleation can be performed. Also, more nuclei are formed in one reaction. A preferable reaction solution amount is 25 to 90%, more preferably 50 to 90% of the volume of the medium volume apparatus container.

In addition, it is also possible to increase the number of parallel twin nuclei generated by extending the nucleation period while the new nuclei continue to be generated, or increasing the number of parallel twin nuclei by extending the nucleation period. . Also in this case, more nuclei are formed in one nucleation reaction, which is preferable.

Normally, the addition of silver salt and halide salt aqueous solution at the time of nucleation is controlled by a silver potential control method such as CDJ (controlled double je
t) method than addition, silver salt and X calculated amount ^- it is preferred to add the salt solution. Specifically, for example, 1 mol / l AgNO ₃
This means that both the aqueous solution and the 1.1 mol / l KBr aqueous solution are added at 10 ml / min for 5 minutes in equilibrium simultaneous mixing. This is because the silver potential is unstable when the AgX particles are absent or only slightly present in the reaction vessel, and therefore the accuracy is not good. In addition, when the production scale is increased, Ag ⁺
The instability of the silver potential is increased due to the greater concentration non-uniformity. Therefore, from that point as well, it is preferable to perform without silver potential control.

The nucleation step is intended to form stable nuclei, but for that purpose, a small amount of crystal growth process may be included. Aqueous silver salt solution and X ^-
When double jet addition of salt solution at a constant speed,
In 4 minutes the generation of new stable nuclei ceases, after which only nuclei growth occurs, which makes the nuclei more stable. Therefore, the nucleation process of the present invention includes the growth of this more stable nucleus. Therefore, the nucleation can also be called seed crystal formation.
Therefore, there is no strict range for the nucleation period, but it is usually 20 minutes or less, and in the case of the method of the present invention, 5 seconds to 10 seconds.
Minutes are more preferred.

It is preferable that the silver salt aqueous solution and the X ^- salt aqueous solution added in the medium amount apparatus and the large amount apparatus are rapidly and uniformly mixed into the reaction solution. Therefore, it is preferable that the silver salt aqueous solution and the X ^- salt aqueous solution are directly added to the reaction solution (that is, directly added below the liquid surface) and vigorously stirred by a stirring blade installed near the addition port. Further, it is preferable to add the addition through a porous body. Particularly in a large-scale apparatus, the addition flux of the aqueous solution of silver salt and halide salt becomes thick, and the nonuniformity of the solute concentration near the addition port becomes larger. This is Ag
This contributes to the performance difference that occurs when the X emulsion production is scaled up. Addition of the solution through the porous body greatly improves the non-uniformity. Here, the porous material has 4 or more holes, preferably 10 or more holes, and more preferably 10 ² to 10 ¹⁵ holes per addition solution, and the hole diameter is 2 mm.
φ or less, preferably 0.5 mmφ to 100Å, more preferably 0.
It has a hole of 1 mmφ to 0.1 μmφ. In particular, the hollow tube type porous membrane is particularly preferable because the support is simple and easy to use.

For details, the description in Japanese Patent Application No. 2-78534 can be referred to.

Further, in the present invention, as a method of supplying solute ions for crystal growth in a large-scale apparatus, an ultrafine grain emulsion (AgC
l, AgBr, AgI and / or a mixed crystal of two or more thereof)
Is particularly preferred. The ultrafine particles are mainly mixed in a large amount of emulsion and then gradually dissolved, and do not cause a non-uniform distribution of the solute above the equilibrium solubility thereof. Therefore, it enables uniform crystal growth of seed crystals in a large-scale apparatus. The ultrafine particles are preferably multi-twin grains (grains containing two or more twin planes in one AgX grain) and defect-free grains substantially free of screw dislocation grains. Here, “substantially” means that the ratio of the number of defective particles is 5% or less, preferably 1
% Or less. The details of the method for preparing the ultrafine particles can be referred to the descriptions in Japanese Patent Application No. 1-183417 and Japanese Patent Application No. 2-142635. Regarding these addition systems and agitators, Japanese Patent Application No. 2-78534, U.S. Patents 3,897,935, 3,790,386,
No. 3,415,650, No. 3,692,283, No. 4,289,733, No. 3,7
The descriptions of 85,777, JP-A-57-92,524, and JP-A-60-117,834 can be referred to.

As the dispersion medium used for the nucleation, a dispersion medium usually used in AgX emulsion production can be used, and gelatin and other hydrophilic colloids described later can be used.
Gelatin is usually preferred. The concentration of the dispersion medium is usually 0.1 to 10% by weight.

The method for adding the silver salt and the halide salt aqueous solution is to add the silver salt aqueous solution to the halide salt aqueous solution by Sngle je
The t method or the reverse mixing method in which an aqueous solution of a halide is added to an aqueous solution of a silver salt can also be used.
The uble jet addition method is preferred.

The addition rate of the aqueous silver salt solution is 2 per reaction solution.
× 10 ^-5 to 10 ^-1 mol / min can be used. The preferable regions such as the addition rate of the silver salt aqueous solution, the gelatin concentration, the pBr of the reaction solution, and the temperature depend on the type of AgX particles to be produced. For example, when producing monodisperse parallel double-twin AgX emulsion grains, while maintaining the temperature at 5 to 48 ° C and pBr1 to 2.5,
Silver salt solution and X ^- salt solution per reaction solution of 6 x 10
^{-4 to} 2.9 × 10 ^-1 mol / min in a gelatin aqueous solution (gelatin concentration 0.1 to 3.0% by weight) is added by double jet to form nuclei. Regarding this, Japanese Patent Laid-Open No. 63-151618 and Japanese Patent Application No. 63-3157.
Reference can be made to the descriptions in No. 41 and Japanese Patent Application No. 1-90089.

Further, when only non-twinned grain nuclei are formed, the excess halogen ion concentration or excess silver ion concentration is 0 to 10 ^-2.1 M /
l, 2 x 10 ^{-5 to} 3 x 10 per reaction solution of silver salt aqueous solution and X ^- salt aqueous solution under the gelatin concentration of 1.0 to 15% by weight.
Nucleate by adding double jet at ^-2 mol / min. Regarding this, the description in Japanese Patent Application No. 63-223739 can be referred to. Other conventional nucleation conditions for AgX particles are described in Japanese Patent Application Nos. 63-223739, 58-113926 and 58-113927.
Issue 58-113928, P. Glafkides, Chimie et Physique
Photographiques, Part 3, Fifth Edition, Edition de
l'Usine Nouvelle, Paris, 1987, VL Zelikman et a
L., Making and Conating Photographic Emulsion (T
You can refer to the description in he Focal Press, 1964).

Ripening process (refers to physical ripening process) A ripening process is often added to the AgX emulsion manufacturing process. For example, in the case of producing monodisperse hexagonal tabular AgX emulsion grains, it is not possible to make only parallel double twin grains at the time of nucleation, and at the same time, other grains (non-twin grains, single twin grains, non-parallel double twin grains) can be formed. Crystal grains, etc.) are also generated. Therefore, in the next aging step, an aging step is added in order to eliminate the other particles. For details, see Japanese Patent Application Laid-Open No. 63-151618, Japanese Patent Application No. 63-315741, Japanese Patent Application No. 1-9008.
The description in No. 9 can be referred to.

In addition, after forming normal crystal nuclei, a physical ripening step may be added to reduce the number of nuclei. TGBogg et al. With respect to the aged, Journal of Photographic Science, 24 8
The description in 1 (1976) can be referred to.

In addition, a physical ripening step may be added to modify the shape of the particles after the crystal growth is completed. Regarding this, the description in JP-A 1-131541 can be referred to.

Since this physical ripening step is usually performed while stopping the addition of solute or at a low speed, the difference in performance between the small-volume manufacturing apparatus and the large-volume manufacturing apparatus is small. Therefore, in the present invention, it is preferable that the ripening process is performed by a large-scale apparatus.

Crystal growing process the crystal growth stage is usually silver and X ^- slower than the rate of addition of the aqueous salt solution new new nuclei are generated, and it is preferable to add faster than Ostwald ripening occurs. This is because the grain size distribution becomes wider when new nuclei are generated or Ostwald ripening occurs during the crystal growth period. Usually, the solute is added at 30-99%, preferably 40-90% of the critical addition rate. Therefore, the control accuracy condition of the supersaturation degree with respect to the reaction solution during crystal growth is looser than that during nucleation. Therefore, if nuclei (seed crystals) in which each factor is sufficiently controlled are used, the performance of the finally obtained AgX emulsion will be the same even if the crystal growth is carried out in a large-scale manufacturing apparatus. It does not differ significantly from the performance of the AgX emulsions we have made. Therefore, according to the present invention, the crystal growth is performed in a large-scale apparatus.

Usually, when the supersaturation degree of the solute in the reaction solution is increased and AgX particle growth is grown by a growth mechanism that has a large contribution of diffusion-controlled growth, AgX particles with a narrow particle size distribution can be obtained.
preferable.

The silver ion and the halogen ion to be added during the crystal growth period are a method of adding an aqueous solution of silver salt and an aqueous solution of halide salt, and an ultrafine grain emulsion (AgCl, AgBr, AgI and / or their size) having a size of 0.1 μmφ or less in advance. It is possible to use a method of adding mixed crystals) or a method of stacking them. Further, a method of increasing the addition rate of silver ions and halogen ions during crystal growth can be used. As a way to increase it, Japanese Patent Publication No. 48-36890
No. 52-16364, the addition rate (flow rate) of the silver salt aqueous solution and the X ^- salt aqueous solution having a constant concentration may be increased, or the concentration of the silver salt aqueous solution and the X ^- salt aqueous solution may be increased. You may let me. Moreover, those may be superposed. The addition rates of Ag ⁺ and X ⁻ may be increased stepwise or continuously and can be selected according to the respective purpose.

As a method of adding halogen ions during mixed crystal formation, C
In addition to the method of adding a solution containing two or more of l ⁻ , Br ⁻ , and I ⁻ , the method of adding Cl ⁻ , Br ⁻ , and I ⁻ as independent addition systems, and the superposition method thereof You can
When the iodide distribution in the grains is gradually increased or gradually decreased, the crystal growth may be performed together with, for example, the iodide content of the added halide aqueous solution may be gradually increased or gradually decreased. The iodide content in the added halide aqueous solution may be rapidly increased or rapidly increased. For details of these, Japanese Patent Application No. 63-223739 and JP-A-55-142329.
No. 58-113926, No. 59-45438, U.S. Pat.
No. 4,242,445, British Patent No. 1,335,925, and the descriptions in the following documents can be referred to.

Further, it is most preferable to add according to a theoretical formula calculated in advance as described in Japanese Patent Application No. 63-223739. The temperature at the time of crystal growth can be usually 40 to 80 ° C.

Other Conditions for AgX Emulsion Production by the Apparatus of the Present Invention In the AgX emulsion production by the method of the present invention, the pH of the reaction solution in each step may be in the range of 1.6 to 10.5 depending on the purpose. Direct surface reversal
When producing an AgX emulsion, it is preferable not to include reduced silver nuclei in AgX grains. In that case, the reaction solution pH is usually preferably 6 or less, more preferably pH 1.6 to 5.6.

Further, in the case of negative type AgX particles, it is preferable to include reduction sensitizing nuclei in the AgX particles. In this case, the pH of the reaction solution is preferably in the range of pH 5 to 10. However, these preferable pH regions depend on pBr of the reaction solution, and as the X ^- concentration decreases and the Ag ⁺ concentration increases, the pH region in which reducible silver nuclei start to generate shifts to the low pH side. .

As the dispersion medium used when an AgX emulsion is produced by the method of the present invention, those commonly used for AgX emulsions can be used, and various hydrophilic colloids such as gelatin can be used. Usually, gelatin is preferred, and in addition to alkali-processed gelatin, acid-processed gelatin, derivative gelatin such as phthalated gelatin,
Gelatin with a methionine content of 50 μmol / g or less
-157024 can be referred to), low molecular weight gelatin (molecular weight 2000-100,000, enzyme-degraded gelatin, acid
Alkali hydrolyzed gelatin) can be used, or a mixture thereof can also be used. As derivative gelatin, gelatin is reacted with various compounds such as acid halides, acid anhydrides, isocyanates, bromoacetic acid, alkane sultones, vinyl sulfonamides, maleinimide compounds, polyalkylene oxides, epoxy compounds, etc. What is obtained is used. Others, graft polymers of gelatin and other polymers, thioether polymers, albumin, proteins such as casein, hydroxyethyl cellulose, carboxymethyl cellulose,
Cellulose derivatives such as cellulose sulfates, sodium alginate, sugar derivatives such as starch derivatives, polyvinyl alcohol, polyvinyl alcohol partial acetal, poly-N-vinyl pyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyvinyl imidazole, polyvinyl pyrazole A variety of synthetic hydrophilic polymeric substances such as single or copolymers can be used alone or in a mixed system.

For details of these, reference can be made to the descriptions in the literature described below.

In order to control the degree of supersaturation during nucleation of the AgX grains, to promote ripening in the ripening process, to promote growth in the crystal growth process, and to effectively perform chemical sensitization during chemical sensitization. A silver halide solvent can be used for smoothing.

Examples of frequently used silver halide solvents include thiocyanate, ammonia, thioether, and thioureas. About this, the description of the literature mentioned later can be referred to.

There is no particular limitation on the additives that can be added during the production of the AgX emulsion by the method of the present invention from grain formation to coating. Additives that can be added are AgX solvents (also called ripening accelerators), dope agents for AgX particles [Group 8 precious metal compounds, other metal compounds (gold, iron, lead, cadmium, etc.), chalcogen compounds, SCN. Compounds, etc.], dispersion media, antifoggants, stabilizers, sensitizing dyes (for blue, green, red, infrared, panchromatic, ortho etc.), supersensitizers, chemical sensitizers (sulfur, selenium, tellurium) , Gold and Group 8 noble metal compounds, phosphorus compounds alone or in combination thereof, most preferably chemical sensitizers comprising a combination of gold, sulfur and selenium compounds, stannous chloride, thiourea dioxide, polyamines And reduction sensitizers such as amine borane-based compounds), fogging agents (organic fogging agents such as hydrazine-based compounds, inorganic fogging agents), surfactants (defoaming agents, etc.), emulsion precipitants, soluble silver salts ( A gSCN, silver phosphate, silver acetate, etc.), emulsion precipitation agent, latent image stabilizer, pressure desensitizing agent,
They are thickeners, hardeners, developers (hydroquinone-based compounds and the like), development modifiers and the like. Specific examples of compounds and methods of use can be referred to the descriptions in the following documents.

In addition, the AgX emulsion may use any combination of known techniques and known compounds described in the following documents.

Research Disclosure vol.176 (item 17643) (Decembe
r, 1978), vol.184 (item 18431) (August, 1979), vo
l.216 (item 21728) (May, 198), JCIA monthly report 1984,
December issue, p.18-27, Journal of the Photographic Society of Japan, Vol. 49, 7 (1986
52), 144-166 (1989), JP-A-58-113926
Issue-113928, 59-90842, 59-142539, 62-25
No. 3159, No. 62-99751, No. 63-151618, No. 62-6251,
62-115035, 63-305343, 62-266538, 63-22
0238, 63-78465, JP-A 1-131541, 1-297649, 2-
146033, Japanese Patent Application 63-315741, 62-208241, 63-31151
8, JP-B-59-43727, US4,707,436, US4,705,744
Issue 4,707,436, THJames, The Theory of The Pho
tographic Process, Fourth Fdition, Macmillan, New Yor
1977, VL Zelkman et al., Making and Coating
Photographic Emulsion (The Focal Press, 1964
Year), P. Glafkides, Chimie et Physique Photographiqu
es, Fifth Edition, Edition de l ′ Usine Nouvelle, Par
is, 1987, Second Edition, Paul Montel, Paris, 1957
Year, KR Hollister, Journsl of Imag, Sic., 31 , 148-15
6 (1987).

(Effect of the invention) In the case of producing a large amount of AgX photographic emulsion by adding a silver salt and an X ^- salt solution in a reaction solution containing at least a dispersion medium and water, nucleation of the emulsion is performed with a medium-weight apparatus, The use of a manufacturing apparatus that performs aging and / or crystal growth in a large-scale apparatus has the following features, compared to the case of using a conventional manufacturing apparatus that performs the process from nucleation to crystal growth in the same large-scale apparatus.

An AgX emulsion with almost the same performance as the AgX emulsion developed with a small amount of equipment for research can be immediately produced in a large amount.

As for the control accuracy of the supersaturation degree in the reaction solution at the time of nucleation, a small amount device is basically better. Therefore, a high-performance AgX emulsion with more controlled nucleation can be produced in a large amount.
In particular, it is particularly effective when producing monodisperse parallel double twinned tabular grains and twin-free grains.

When producing tabular AgX emulsion grains having parallel twin planes, nucleation may be performed at a low temperature and the subsequent ripening step may be performed at a high temperature. In the conventional device, the temperature of a large number of devices is raised and lowered in this case, and the energy consumption is large, but in the device of FIG. 1 of the present invention, the operation of raising and lowering the temperature is eliminated.
Therefore, it has an advantage of energy saving and quickness.

(Example) Hereinafter, the present invention will be further described with reference to examples, but the embodiments of the present invention are not limited thereto.

Example 1 The manufacturing process of FIG. 1 was used. The volume of the reaction vessel of the medium-volume apparatus is 40 l, and the volume of the intermediate vessel and the volume of the reaction vessel of the large-volume apparatus are both 960 l. The temperature of the medium volume device and the intermediate container is always kept at 30 ° C, and the temperature of the large volume device is always 75 ° C.
Kept. The temperature was set in a constant temperature water bath. In addition, the addition of the silver salt and halide salt aqueous solution was carried out through the hollow tube type porous membrane in the large-volume apparatus and the medium-volume apparatus.

First, a gelatin aqueous solution [H ₂ O
24 liters, low molecular weight gelatin 168 with average molecular weight () = 20,000
g, KBr 108 g, pH 5.5, 30 ° C.] was added. Do with stirring
By the uble jet method, AgNO ₃ aqueous solution [16 g of AgNO _{3 in} 100 ml =
0.7g of 20,000 gelatin and 0.14ml of HNO ₃ (1N))
1200 ml each of KBr aqueous solution [having 12.1 g of KBr and 0.7 g of 20,000 gelatin in 100 ml] at the same time while stirring
1320 ml was added per minute. After 1 minute, the reaction solution was transferred to an intermediate container, and 3360 ml of an aqueous gelatin solution [640 g of deionized alkali-treated gelatin, pH 5.5] was added to the intermediate container.
The medium volume device was washed once with water and drained from f. Then, again, an aqueous gelatin solution was added to the medium weight apparatus, and the same operation as above was performed 11 times. The time required was 66 minutes. About 350 l of the reaction solution stored in the intermediate container was transferred to the reaction container of a large-scale apparatus maintained at 75 ° C. After the temperature of the reaction solution reached 75 ° C., it was aged for another 12 minutes, and then the AgNO ₃ aqueous solution (1
5 wt%) was added at 7200 ml at 1920 ml / min.

Next, 2256 ml of NH ₃ aqueous solution (25 wt%) and NH ₄ NO ₃ aqueous solution (5
0 wt%) 2256 ml of the mixed solution was added, and the mixture was aged for 20 minutes.
Next, 3N HNO ₃ aqueous solution was added to adjust the pH to 5.5. Further KBr
3384 ml of an aqueous solution (10% by weight) was added, and an AgNO ₃ aqueous solution (15
(% By weight) and a KBr aqueous solution were used to add CDJ at a silver potential of -20 mV (vs. room temperature saturated calomel electrode). The AgNO ₃ aqueous solution was added first at 2400 ml / min for 10 minutes, and subsequently at 4320 ml / min for 20 minutes. After 2 minutes, the reaction solution was transferred to a vessel for washing with sedimentation (temperature: 30 ° C.), the emulsion was washed with water by an ordinary sedimentation washing method, and 12 kg of gelatin was added and redispersed to pH 6.
4, adjusted to pAg8.6. A transmission electron microscope photographic image (TEM image) of the obtained replica of the AgX emulsion particles was observed. The results are shown in Table 1.

In the production process, the time required for ripening and crystal growth in the large-scale apparatus is 72 minutes, which is in balance with the time required for the nucleation, and the production of the emulsion can be controlled automatically and smoothly with good reproducibility. It was conducted. In addition, in this step, all the solutions were added directly into the mixing box (d in each figure).

Comparative Example 1 A reaction vessel having a volume of 4 liters was used to carry out a nucleation → aging → crystal growth reaction with the same formulation as in Example 1. However, in contrast to Example 1, the nucleation reaction was on a 1/20 scale, and the aging and crystal growth reactions were on a 1/240 scale. Further, each additive solution has the same composition as the additive solution of Example 1. That is, 1.2 liters of the same aqueous gelatin solution as in Example 1 was placed in the reaction vessel and kept at 30 ° C. While stirring the AgNO ₃ aqueous solution and the KBr aqueous solution by the double jet method, 66 ml of each was simultaneously added at 60 ml / min. After 1 minute, 168 ml of an aqueous gelatin solution was added and uniformly mixed, and then the temperature was raised to 75 ° C. After raising the temperature and aging it for 12 minutes, 8 mg of AgNO ₃ aqueous solution was added.
30 ml was added per minute. Next, a mixed solution of 9.4 ml of NH ₃ aqueous solution and 9.4 ml of NH ₄ NO ₃ aqueous solution was added, and the mixture was aged for 20 minutes. Then 3
An aqueous HNO ₃ solution of N was added to adjust the pH to 5.5. Then KBr solution 14.
1 ml was added, and CDJ was added using AgNO ₃ aqueous solution and KBr aqueous solution at a silver potential of −20 mV. Add the AgNO ₃ aqueous solution first
An addition of 0 ml / min for 10 minutes followed by an addition of 18 ml / min for 20 minutes. After 2 minutes, the temperature was lowered to 30 ° C., the emulsion was washed with water by a usual precipitation water washing method, 50 g of gelatin was added and redispersed, and the pH was adjusted to 6.4 and pAg 8.6. The TEM image of the replica of the obtained AgX emulsion grains was observed. The results are shown in Table 1.

Comparative Example 2 From the nucleation to the crystal growth, only the large-scale apparatus shown in FIG. 1 was used. The formulation was carried out by simply scaling up the formulation of Comparative Example 1 by 240 times. The characteristic values of the obtained emulsion grains are shown in Table 1.

According to the results in Table 1, the characteristic values of the high-aspect-ratio monodisperse tabular grains prepared by the small-scale apparatus for research (Comparative Example 1) and the characteristic values of Example 1 were almost the same, but comparison with the conventional method was performed. Example 2 shows that the characteristic values have deteriorated considerably. Therefore, it can be said that the effects of the present invention were confirmed in Example 1. The nucleation reaction of the example has a container capacity of 10 compared with the comparative example 1.
Double the volume of the reaction solution is 20 times. That is, since the medium-volume device container is dedicated to nucleation, the container capacity is used more effectively. In addition, the hollow tube-type porous membrane was prepared by slowly inserting a sharp needle into a Teflon tube,
The holes were made at a rate of 1 / 2.25 mm ² . The number of holes is 100 per 1 addition system for small volume equipment, 2000 for medium volume equipment,
It has 24,000 pieces in a mass device. One end of the tube is sealed with a stopper.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of the relationship between the medium-volume device, the intermediate container and the large-volume device of the present invention. A is a medium-weight apparatus, E is a large-volume apparatus, and the stirring apparatus is the stirring apparatus described in JP-A-51-72,994. However, the addition port of the silver salt and halide salt aqueous solution of each device is a hollow tube type porous membrane. In addition, D is a large-capacity container, F, G, and H are liquid supply pipes, and f is a waste water pipe when the medium-volume device is washed. Indicates an addition system of an aqueous silver nitrate solution and an aqueous halide salt solution. i is a hollow tube type porous addition tube. FIG. 2 shows a cascade type multi-stage batch type small amount apparatus,
FIG. 3 shows a stepwise type multi-stage batch type small amount apparatus. a and b are movable side walls. FIG. 4 (a) is a cross-sectional view of a hollow tubular porous tube,
(B) is a top view. j indicates the flux of the effluent. k indicates a fine hole. Further, d in FIGS. 1 to 3 indicates a mixing box.

Claims (6)

(57) [Claims] 1. A method for producing a silver halide emulsion having at least a dispersion medium and silver halide grains, wherein the nucleation of the grains is carried out in a medium-capacity batch type or multi-stage batch type reaction device, and the produced nucleus emulsion is Transfer to a large-scale manufacturing apparatus or transfer the nuclear emulsion to an intermediate container and then transfer to a large-scale manufacturing apparatus, and perform aging and / or crystal growth in the large-scale manufacturing apparatus, (volume of the large-scale manufacturing apparatus / Capacity device capacity) = y is 3 to 2000, and the number of times of liquid transfer (n) is 2 to 2000 times, a method for producing a silver halide emulsion. 2. The silver halide according to claim 1, wherein the capacity of the medium weight device is 5 to 500 liters, the y value is 3 to 400, and the n value is 3 to 400. Emulsion manufacturing method. 3. It is characterized in that 2 to 30 reactors of the medium capacity are used, the temperature of the intermediate container is kept at 10 to 45 ° C., and the temperature of the large volume device is kept at 40 to 80 ° C. A method for producing a silver halide emulsion according to claim 1. 4. The y value is 3 to 50, the n value is 3 to 20, and the nucleation is performed by an equilibrium simultaneous mixing method of an aqueous solution of a silver salt and a halide salt, and the equilibrium. The method for producing a silver halide emulsion according to claim 1, wherein the simultaneous mixing is performed by a flow rate control method without using a silver potential control method. 5. The method according to claim 1, wherein the silver salt aqueous solution and the halide salt aqueous solution are added during the nucleation and crystal growth through a porous body having 4 or more pores per one added solution. Method for producing silver halide emulsion of. 6. The silver halide emulsion according to claim 1, wherein 70% or more of the total projected area of the silver halide grains is composed of tabular silver halide grains having parallel twin planes. 1) The method for producing a silver halide emulsion described in 1).