JP2003315949A - Method for forming silver halide emulsion grain and apparatus therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form silver halide emulsion grains having a small grain size and excellent in monodispersity because a mixed state in static mixing can be made optimum. <P>SOLUTION: An aqueous silver nitrate solution X and an aqueous halogen salt solution Y are spurted from a first nozzle 34 formed at one end of a mixing chamber 20 and a second nozzle 36 formed at the other end into the mixing chamber 20 having a larger tube diameter D<SB>1</SB>than the orifice diameters D<SB>2</SB>, D<SB>3</SB>as turbulent flows A<SB>1</SB>, A<SB>2</SB>going straight in opposite directions. In the mixing chamber 20, the two solutions are instantaneously mixed and reacted by overlapping eddy viscosity C due to the straight flow A<SB>1</SB>and eddy viscosity D due to the straight flow A<SB>2</SB>in such a way that the overlap E of the eddy viscosities C, D is made largest in a place where the eddy viscosities C, D become maximum, and the resulting mixed reacted liquid Z is delivered form an outlet pipe 26. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for forming silver halide emulsion grains, and more particularly to a technique for forming silver halide emulsion grains using a static mixing device.

[0002]

2. Description of the Related Art When forming silver halide emulsion grains used in a silver halide light-sensitive material, there are roughly two steps. One is a nucleation step for forming seed grains of silver halide emulsion grains, and the other is a grain growth step for growing seed grains formed in the nucleation step into grains having a size suitable for a light-sensitive material. is there.

First, in the nucleation step, for example, in order to prepare tabular grains having a uniform shape, the probability of occurrence of double twinning, in which the grain size distribution is uniform at the stage of seed grains which are the basis of tabular grains, is increased. It is necessary. Further, in order to grow such tabular grains, in order to regulate the growth direction, seed grains for growth formed by nucleation are added to a system in which host grains for growth are present, and Ostwald ripening is performed. It is effective to proceed. Such seed particles are required to have a fine size and excellent monodispersity.

In order to form such seed particles, an aqueous solution of silver salt (which will be described below as an example of "an aqueous solution of silver nitrate") and an aqueous solution of halogen salt are mixed at a very low concentration in a mixing reaction apparatus and both are mixed. If the liquid is reacted, it is possible to form desired twinned seed particles unless the stirring or mixing conditions are too weak, but it is not industrially viable under low concentration conditions. Therefore, in order to form seed particles or to grow seed particles at a concentration level that is industrially profitable, a reaction under a high concentration condition is necessary.

Further, in order to stably form fine silver halide emulsion grains in the nucleation step and grain growth step, it is necessary to devise a device so that nucleation and grain growth do not occur at the same time. As a device, it is desirable to use a small capacity static mixing device that does not generate backflow. Here, the static mixer refers to a mixer having no stirring means such as a stirrer in the mixing field.

A method for forming silver halide emulsion grains using such a static mixing apparatus is disclosed in JP-A-4-292.
No. 416, JP-A No. 11-217217, and JP-A No. 2000-187293, which disclose two jet jets of a high Re (Reynolds number) silver nitrate aqueous solution and a halogen salt aqueous solution into a T-shaped tube or By colliding at an intersection of very narrow pipes such as a Y-shaped pipe, both liquids are instantaneously mixed and reacted, and the mixed reaction liquid is discharged in a short time. For example, as shown in FIG. 9, a silver nitrate aqueous solution X and a halogen salt aqueous solution Y having a flow rate of several m / sec are supplied from the first addition pipe 6 and the second addition pipe 7 at the intersection 8 of the very narrow pipes on the order of milliseconds. To cause a mixed reaction of the silver nitrate aqueous solution X and the halogen salt aqueous solution Y, and the mixed reaction solution Z is discharged from the discharge pipe 9.

[0007]

However, as in the conventional static mixer, it is necessary to increase the velocity of the jet stream in order to cause both liquids, which are high-speed turbulence, to collide with each other to increase the mixing efficiency. However, when the velocity of the jet flow is increased, frictional heat is generated due to the liquid-liquid friction of both liquids. Since the reaction for the formation of silver halide emulsion grains is an exothermic reaction, if frictional heat is applied to the exothermic reaction, the seed grains formed by the reaction between the aqueous silver nitrate solution and the aqueous halogen salt solution will grow by Ostwald ripening. However, there is a drawback in that the silver halide emulsion grains are formed finely and it is difficult to form silver halide emulsion grains having good monodispersity.

Further, the high-speed turbulent jet flow is liable to cause cavitation, and bubbles due to cavitation tend to collect to form a gas-liquid interface in the static mixer, which causes nonuniformity of mixing and reaction. There is a drawback that it is difficult to form fine silver halide emulsion grains having good monodispersity.

Therefore, in order to solve the conventional drawbacks, the applicant jets an aqueous solution of a halogen salt (or an aqueous solution of silver nitrate) from the first nozzle 1 into the mixing chamber 2 as a turbulent rectilinear flow A as shown in FIG. Then, the straight flow A is ejected from the first nozzle 1 having a small diameter to the mixing chamber 2 having a larger diameter than that of the first nozzle 1 so that the mixing chamber 2
Straight ahead of the second nozzle 3 to a position before the maximum eddy viscosity formed in the maximum flow velocity or to a position before the maximum flow velocity of the rectilinear flow A decreases to 1/10 or less. By jetting as a turbulent cross flow B that is substantially orthogonal to the flow A and entraining it in the straight flow A, the two solutions of the silver nitrate aqueous solution and the halogen salt aqueous solution are utilized by utilizing the eddy viscosity generated in the mixing chamber 2. A static mixing device 5 has been developed, which is configured to instantaneously mix and react to discharge the mixed reaction liquid from the discharge pipe 4.

As described above, the static mixer 5 for injecting the straight flow A and the cross flow B into the mixing chamber 2 and causing the mixing reaction by utilizing the eddy viscosity formed in the mixing chamber 2 is a halogen salt aqueous solution and silver nitrate. Compared to the conventional static mixing device that collides the aqueous solution at the intersection of narrow pipes, friction heat during mixing of the silver nitrate aqueous solution and the halogen salt aqueous solution is reduced, and cavitation is prevented, resulting in an efficient mixing reaction. It is possible to optimize the mixed state in static mixing.

However, since the static mixing apparatus utilizing such eddy viscosity is a novel apparatus that goes beyond the conventional idea, the apparatus configuration is diversified and various silver nitrate aqueous solutions and halogen salt aqueous solutions are used. It is necessary to be able to handle various mixed reaction conditions.

For example, in the static mixing device of FIG. 10, a jet flow, which is a straight flow of a high-speed turbulent flow, is accompanied by a cross flow of a low-speed turbulent flow which is substantially orthogonal to the straight-flow flow. A so-called "one-jet method" for forming eddy viscosity in the above, and a so-called "double-jet method" for forming eddy viscosity in the mixing chamber by using two jet streams is also possible.

The present invention has been made in view of the above circumstances, and in a so-called "double jet system" in which at least two jet streams are used to form eddy viscosity in a mixing chamber,
Since frictional heat at the time of mixing an aqueous solution of silver nitrate and an aqueous solution of a halogen salt can be prevented and cavitation can be prevented, the mixing reaction can be efficiently performed, and the mixing state in static mixing can be optimized. An object of the present invention is to provide a method and an apparatus for forming silver halide emulsion grains capable of forming silver halide emulsion grains having a small grain size and excellent monodispersibility.

[0014]

In order to achieve the above-mentioned object, the present invention jets an aqueous solution of silver salt and an aqueous solution of halogen salt from respective nozzles and mixes them into a mixing chamber having a diameter larger than that of the nozzles. A method of forming silver halide emulsion grains by reacting and discharging a mixed reaction solution from an outlet having a diameter smaller than the diameter of the mixing chamber, wherein the silver salt aqueous solution and the halogen salt aqueous solution are mixed with each other. It is characterized in that the silver salt aqueous solution and the halogen salt aqueous solution are instantaneously mixed and reacted by being jetted into the mixing chamber as at least two straight-flowing turbulent flows that oppose each other from one end and the other end.

Further, in order to achieve the above object, the present invention is a silver halide emulsion for forming silver halide emulsion grains by mixing an aqueous solution of silver salt and an aqueous solution of halogen salt in a static mixer and reacting them. In the particle forming device, the static mixing device includes a mixer having a cylindrical mixing chamber in which the silver salt aqueous solution and the halogen salt aqueous solution are mixed and reacted with each other, and the mixing is performed from one end of the mixing chamber. At least one first jet of the silver salt aqueous solution as a turbulent rectilinear flow into the chamber
A nozzle, at least one second nozzle provided at the other end of the mixing chamber so as to face the first nozzle, and ejects the halogen salt aqueous solution into the mixing chamber as a turbulent rectilinear flow; and the mixing chamber. And a discharge port for discharging the mixed reaction liquid which has been mixed and reacted in the mixing chamber from the mixing chamber, and the cylindrical diameter of the mixing chamber is larger than the diameters of the nozzle and the discharge port. Characterize.

The present invention, like the conventional static mixer,
Rather than making the high-speed turbulence of the silver salt aqueous solution and the high-speed turbulence of the halogen salt aqueous solution collide with each other at the intersection of very narrow pipes such as a T-shaped tube or a Y-shaped tube, the mixing reaction is instantaneously performed in the collision field. Focusing on eddy viscosity, which is known as mixing property evaluation in turbulent flow field, two eddy viscosities formed by at least two jet flows of a halogen salt aqueous solution and a silver salt aqueous solution facing each other in a static mixer. By overlapping with each other, both liquids are instantaneously mixed and reacted.

Here, in the present invention, "at least two opposing straight flows of a silver salt aqueous solution and a halogen salt aqueous solution"
Is not limited to two opposing straight flows of one silver salt aqueous solution and one halogen salt aqueous solution, for example, two silver salt aqueous solutions and two halogen salt aqueous solutions in total of 4 It means that the straight-flowing flows of the books facing each other may be the same, or the straight-flowing flows of more than that may be the facing straight-flow. For example, in the case of jetting two straight flow streams of a silver salt aqueous solution and two straight flow streams of a halogen salt aqueous solution facing each other, the silver salt concentration or the type of silver salt (silver nitrate, silver iodide, etc.), the halogen salt aqueous solution. It is also possible to use a plurality of types of silver salt aqueous solutions and halogen salt aqueous solutions having different halogen salt concentrations, halogen types, and the like. In this case, the number of nozzles may be set according to the number of plural kinds of silver salt aqueous solutions or halogen salt aqueous solutions to eject plural kinds of silver salt aqueous solutions or halogen salt aqueous solutions. Alternatively, one salt aqueous solution may be provided, and a plurality of types of silver salt aqueous solutions and halogen salt aqueous solutions may be sequentially ejected at the initial stage of the reaction, the intermediate stage of the reaction, and the final stage of the reaction.

That is, the static mixing device is a mixer in which a cylindrical mixing chamber is formed so that eddy viscosity is generated in the mixing chamber.
At least one first with a bore smaller than the tube diameter of the mixing chamber
A nozzle and at least one second nozzle are formed, and vortex viscosity is formed by ejecting the liquid from a small-diameter nozzle into a mixing chamber having a larger diameter than that, and the diameter of the discharge port is reduced. By applying pressure to the mixing chamber,
It was configured so that a gas-liquid interface due to cavitation was not easily formed in the mixing chamber.

For example, in the case of an example of two opposing straight flow streams, the two jet streams jetted from the first nozzle and the second nozzle are turbulent by being jetted to a place wider than their width. The eddy viscosity is generated by the flow, and the mixing effect can be remarkably enhanced by overlapping the eddy viscosities with each other. However, in the case where the pipe diameter does not change like the above-mentioned T-shaped pipe or Y-shaped pipe. Does not generate eddy viscosity, and such an effect cannot be expected. Further, a "double jet method" in which a silver salt aqueous solution and a halogen salt aqueous solution are jetted into the mixing chamber as two straight turbulent flows of a silver salt aqueous solution and a halogen salt aqueous solution from a first nozzle and a second nozzle formed at one end and the other end of the mixing chamber, respectively. The two eddy viscosities formed by the respective rectilinear flows overlap each other, so that the silver salt aqueous solution and the halogen salt aqueous solution are instantaneously mixed and reacted. In this case, if two straight flow flows collide with each other immediately after they are jetted into the mixing chamber, heat generation due to liquid-liquid friction occurs and Ostwald ripening progresses. Therefore, two vortex viscosities formed by the two straight flow flows are generated. It is preferable that the portion where the eddy viscosities overlap with each other is maximized at the position where is maximum. Therefore, the distance between the opposing first and second nozzles, in other words, the mixing chamber, is set so that the overlapped portion of the eddy viscosities is maximized at the position where the eddy viscosities of the two straight flow streams are maximized. It is preferable to properly set the length. In order to set the separation distance between the first nozzle and the second nozzle, it is necessary to know the position where the two eddy viscosities are maximum, but the position where the eddy viscosity is maximum is already commercially available in Japan as flow analysis software. R-Fl, a numerical analysis software manufactured by R Flow Co., Ltd.
Since it can be grasped by performing a simulation in advance using ow, the distance between the pair of nozzles may be determined based on that.

In a preferred embodiment of the present invention, it is preferable that the flow velocities of at least two linearly advancing streams are equal to each other. This is because the position where eddy viscosity is generated differs depending on the flow velocity of the straight flow, and if the flow velocity of the straight flow is too different, the overlapping portion of the eddy viscosities becomes small and the mixing performance is adversely affected.

Furthermore, in a preferred embodiment of the present invention, it is preferable that at least two of the opposing straight flow streams are in the form of a thin film. This is because when the thin film is used, the liquid-liquid interface area of the two rectilinear flows is increased and the mixing performance is improved, so that the jet flow velocity of the rectilinear flow can be decelerated. If the good mixing performance can be maintained even if the jet flow velocity is reduced, the selection range of the material forming the nozzle becomes large.

As described above, the present invention optimizes the mixing state in the static mixing device in the so-called "double jet system" in which at least two jet streams facing each other are used to form eddy viscosity in the mixing chamber. Therefore, silver halide emulsion grains having a small grain size and excellent monodispersity can be formed.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the method and apparatus for forming silver halide emulsion grains according to the present invention will be described below in detail with reference to the accompanying drawings. In addition, in the present embodiment, an example of two straight traveling flows facing each other will be described.

FIG. 1 is a production line 1 of a silver halide light-sensitive material equipped with a silver halide emulsion grain forming apparatus of the present invention.
It is the figure which showed 0 conceptually.

Production line 10 for silver halide light-sensitive material
Includes a nucleation step of forming fine grain nuclei of silver halide emulsion grains, and a nucleus growing step of bringing fine grain nuclei formed in the nucleation step into contact with silver halide emulsion grains for growth to grow fine grain nuclei. Composed of. Then, a static mixing device 12, which is a device for forming silver halide emulsion grains of the present invention, is provided in the nucleation step, and a growth tank 16 equipped with a heating jacket 14 is provided in the nucleation step.

In the static mixing device 12, the aqueous solution of silver nitrate X and the aqueous solution of halogen salt Y are instantaneously mixed and reacted to form a mixed reaction solution Z containing fine grain nuclei of silver halide emulsion grains, and immediately in the growth tank 16. Sent. The fine grain nuclei sent to the growth tank 16 grow by Ostwald ripening while being stirred by a stirrer 18 in a solution of silver halide emulsion grains for growth. For the formation of silver halide emulsion grains for growth in this nucleation step, it is preferable to use the same static mixing device used in the nucleation step.

FIG. 2 shows a static mixer 12 according to the present invention.
It is a conceptual diagram showing the structure of.

As shown in FIG. 2, the static mixing device 12 is
First, the silver nitrate aqueous solution X is introduced into the mixing chamber 20 through an opening on one end side of a mixer 22 in which a cylindrical mixing chamber 20 for mixing and reacting the silver nitrate aqueous solution X and the halogen salt aqueous solution Y is formed.
Is connected to the second conduit 28 and the second conduit 28 for introducing the halogen salt aqueous solution Y into the mixing chamber 20 is connected to the opening on the other end side. Further, the mixed reaction liquid Z which has been mixed and reacted in the mixing chamber 20 is provided at the opening of the center of the mixing chamber 20.
A discharge pipe 26 for discharging from is connected.

A first orifice 30 and a second orifice 32 are provided inside the tips of the first conduit 24 and the second conduit 28, respectively, whereby the first conduit 24 and the second conduit 28 are provided. A first nozzle 34 and a second nozzle 36 for injecting the turbulent rectilinear flows A ₁ and A ₂ are formed in this. In the present embodiment, an example in which the silver nitrate aqueous solution X is jetted from the first nozzle 34 and the halogen salt aqueous solution Y is jetted from the second nozzle 36 will be described, but they may be reversed.

As a method of forming the first and second orifices 30 and 32, a block-shaped orifice material 23 is formed by drilling, and a hole of about 100 μm is formed in the orifice material such as metal, ceramics or glass. Known as a machining method for precisely opening a hole, micro cutting, micro grinding, jetting, micro electric discharge machining, LIG
A method, laser processing, SPM processing, etc. can be used conveniently.

The material of the orifice material 23 is preferably one having good workability and hardness close to that of diamond. Therefore, as the material other than diamond, various metals or metal alloys that have been subjected to hardening treatment such as quenching, nitriding treatment, or sintering treatment can be suitably used. In addition, ceramics have a high hardness and are more workable than diamond, and thus can be suitably used. In this embodiment, the structure of the first nozzle 34 and the second nozzle 36 will be described with an example of an orifice, but any method other than the orifice can be used as long as it has a function of ejecting a turbulent liquid. Can be used.

Further, the first conduit 24 and the second conduit 28 are provided with a pressurizing means (not shown) so that the halogen salt aqueous solution Y and the silver nitrate aqueous solution X are supplied to the first and second nozzles 34 and 36.
Is supplied under pressure. Various means are known as a pressurizing means for applying a high pressure to a liquid, and any means can be used, but relatively inexpensive and easy means such as a plunger pump and a booster pump are available. It is preferred to use a reciprocating pump. Further, although it is not possible to generate a high pressure as much as a reciprocating pump, some of the rotary pumps are of a high pressure generating type, so that such a pump can also be used.

Then, as shown in FIG. 3 and FIG.
From the nozzle 34 and the second nozzle 36, the silver nitrate aqueous solution X and the halogen
With the salt solution Y from one end and the other end of the mixing chamber 20.
Two turbulent straight flow A₁, A₂As the mixing chamber 20
Ejection, these two straight flow A ₁, A₂Formed by
By overlapping the two eddy viscosities C and D
Instantly reacts with an aqueous solution of halogen halide and an aqueous solution of silver nitrate
To form a mixed reaction solution Z containing silver halide emulsion grains.
To do.

The mixing reaction is such that when the eddy viscosities C and D formed in the mixing chamber 20 by the two high-velocity, straight-flowing turbulent flow streams A ₁ and A ₂ are maximized, the overlapped portion is generated. By overlapping so that E becomes as large as possible, high-performance mixing efficiency is obtained.

Therefore, the above-mentioned mixing chamber 20, the first and second nozzles 34 and 36, and the discharge pipe 26 of the static mixing device 12 are formed so as to have the following relationship.

That is, it is necessary to form eddy viscosities C and D in the mixing chamber 20, and as shown in FIG. 2, the cylinder diameter D ₁ of the mixing chamber 20 is the orifice diameter D ₂ of the first nozzle 34, The diameter is larger than the orifice diameter D ₃ of the two nozzles 36. Specifically, the dimensional ratio of the cylinder diameter D ₁ of the mixing chamber 20 to the orifice diameter D ₂ of the first nozzle 34 is preferably 1.1 times to 50 times, more preferably 1.1 times to 20 times. Is the range. Similarly, the orifice diameter D ₃ of the second nozzle 36
The ratio of the cylinder diameter D ₁ of the mixing chamber 20 to
The range is preferably 50 times, more preferably 1.1 times to 2 times.
The range is 0 times.

The straight flow A₁, A₂In the mixing chamber 20
Immediately after the jet, there is no collision and the straight flow A₁, A₂To
Therefore, the two eddy viscosities C and D formed in the mixing chamber 20 are
-It is preferable to make the area E that overlaps as large as possible.
Yes. To this end, the first nozzle 34 and the second nozzle facing each other are
The separation distance L of the rule 36, in other words, the length of the mixing chamber
It is preferable to set. In this way, the first nozzle 34
And properly setting the separation distance L between the second nozzle 36 and
Then, the maximum eddy viscosity C and D overlap each other.
It is possible to increase the size of the part E that is
It is also possible to overlap C and D almost completely.
Is. Therefore, know the position where the eddy viscosities C and D are maximum.
Although it is necessary, the mixing chamber 20 that maximizes the eddy viscosities C and D
The position is based on the flow analysis software that has already been marketed in Japan.
Made by Earl Flow Co., which is well known as dynamic analysis software
Using the numerical analysis software, R-Flow, of the
The vortex viscosity C from the first nozzle 34
And the distance from the second nozzle 36 to the eddy viscosity D
You can figure it out. In this case, minutes from Figures 3 and 4
As can be seen, the position where the eddy viscosities C and D are maximum is pinpointed.
Area, not the area. Therefore, the first nozzle 34 and
The separation distance L of the second nozzle 36 is the maximum of the eddy viscosities C and D.
The point P, which is the approximate center of the eddy viscosities C and D.₁, P₂
And point P₁And point P₂When match
From the first nozzle of the point P₁And from the second nozzle
INT P₂Up to the total value. Also, the point
P₁, P ₂Another way to figure out is the numerical solution above.
When analyzed with analysis software, straight flow A ₁, A₂Eddy viscosity
Point P where C and D are maximum₁, P₂Goes straight A₁,
A ₂Is related to the flow velocity of₁, A₂Maximum velocity of
(Usually the flow velocity at the first or second nozzle position) is 1/10
It corresponds approximately to the position where it decreases. Therefore, straight flow A₁, A
₂Calculate the position where the maximum flow velocity of
INT P₁, P₂You may grasp. Thus, eddy viscosity
The eddy viscosity C and D at the position where the properties C and D are maximized.
By burlap, straight flow A₁And straight ahead flow A₂Liquid
Improves the mixing reaction performance by increasing the contact efficiency at the liquid interface.
In addition to the effect of making it go straight₁And straight ahead flow A₂Can collide
It also has the effect of suppressing heat generation due to liquid-liquid friction due to.

Further, the small diameter first and second nozzles 34, 36 are provided.
When the liquid is ejected into the mixing chamber 20 having a diameter larger than that by a high-speed flow, cavitation easily occurs, and a gas-liquid interface is formed in the mixing chamber 20 by this cavitation, which lowers the mixing efficiency. Therefore, in order to improve the mixing efficiency by utilizing the eddy viscosities C and D, it is necessary to prevent the gas-liquid interface from being formed in the mixing chamber 20. Therefore, FIG.
The diameter D ₄ of the discharge pipe 26 to the third orifice 3
It is necessary to reduce the tube diameter by 8 to make it smaller than the cylinder diameter D _{1 of} the mixing chamber 20 and increase the pressure in the mixing chamber 20 for mixing. This will eliminate cavitation,
The mixing efficiency is further improved. However, even if the pressure in the mixing chamber 20 is increased by squeezing the discharge pipe 26 with the third orifice 38,
Cavitation cannot be completely eliminated, and it is important to have a structure in which the mixed reaction liquid Z is easily discharged to the discharge pipe and no dead space exists so that fine bubbles due to cavitation do not unite and grow into a large bubble. Is. For that purpose, rather than connecting the discharge pipe 26 to the mixing chamber 20 and narrowing the inlet of the discharge pipe 26 with the third orifice 38 as shown in FIG. And a discharge part 20A is formed in the mixing chamber 20.
It is preferable to connect the discharge pipe having the third orifice 38 to the point of view of increasing the eddy viscosity generation field. In order to minimize the residence time in the portion of the discharge pipe 26 that does not contribute to mixing, the discharge pipe 26 should be shortened as much as possible.
Connect to 6.

By the way, in the case where there is no mixing chamber 20 forming the eddy viscosities C and D, a very long mixing field is required for complete mixing, and the first mixed one and the last mixed one are required. However, the time interval becomes longer and the grain size distribution of silver halide emulsion grains becomes wider.

Further, the first nozzle 34 and the second nozzle 36
The shape of the jet flow ejected from the mixing chamber 20 to the mixing chamber 20 is the first and second
First and second orifices 3 provided in the nozzles 34, 36
It is regulated by 0, 32, and the shape of the jet flow affects the mixing reaction performance. Therefore, depending on the purpose of the mixed reaction, it is preferable to appropriately use the first and second orifices 30 and 32 that form a jet flow shape such as a thread line shape, a conical shape, a slit shape, or a fan shape. For example, in the case of a reaction having a very high reaction rate on the order of milliseconds, the two straight flow streams A ₁ , so that the eddy viscosities C and D are instantaneously maximized in a narrow range as much as possible,
It is necessary to eject A ₂ , and the first and second orifices 30 and 32 forming a filamentary jet flow shape are preferable. Further, when the reaction speed is relatively slow, the straight flow streams A ₁ and A ₂ are jetted so that the eddy viscosities C and D are maximized in the widest possible range, and the liquid solution produced by the straight flow streams A ₁ and A ₂ is generated. It is better to increase the interfacial area, and in this case, the first and second orifices 30 and 32 that form a thin jet flow shape are preferable. Further, in the case of a reaction rate intermediate between a very slow reaction rate and a relatively slow reaction rate on the order of milliseconds, the first and second orifices 3 forming a conical jet flow shape.
0 and 32 are preferable.

FIGS. 5 to 8 show first and second jet line-shaped, conical, slit-shaped, and fan-shaped jet flow shapes.
The orifices 30 and 32 of FIG. 2 are illustrated. In each drawing, (a) is a view of the orifice from the tip side, (b) is a longitudinal sectional view of the orifice, and (c) is a transverse sectional view of the orifice. .

FIG. 5 shows a linear flow A of a thread line.₁(A₂)
First and second orifices 3 for jetting into the joint chamber 20
It is 0, 32 and is formed in a thread line shape. FIG. 6 shows a conical
Straight flow A₁(A₂) For squirting into the mixing chamber 20
And the second orifices 30, 32, with the tip open
The trumpet is formed into a tubular shape. FIG. 7 shows a straight flow A of a thin film. ₁
(A₂) Into the mixing chamber 20 and the first and second
The orifices 30 and 32 are formed in a rectangular slit shape.
Be done. In this case, straight flow A₁, A₂The thin film surfaces of
Go straight A₁, A₂Flow straight when forming the direction of
A₁, A₂It is more preferable because the liquid-liquid interface area between them becomes large.
Good FIG. 8 shows a straight flow A of a fan-shaped thin film.₁(A₂) Mixed
First and second orifices 3 for jetting into chamber 20
0 and 32, and the tip portion is formed by expanding the diameter in a fan shape.

Regarding the Reynolds number when the cross section of the conduit is not circular like the slit-shaped orifice shown in FIG. 7, "Chemical Engineering Theory" (Hario Hikita, Asakura Shoten)
It is shown that can be handled as follows. That is, when S is “cross-sectional area” and lp is “length of solid wall periphery in contact with fluid”, the equivalent diameter De is De = 4S
/ Lp is defined. Since the slit-shaped orifice has a closed groove structure, if the short side is a and the long side is b, then lp
= 2 (a + b). Therefore, the equivalent diameter De is
It is shown by the following equation (1).

[0044]

## EQU1 ## De = 4 (ab) / 2 (a + b) = 2ab / (a + b) ... Equation (1) When calculating the turbulent flow expressed in the present invention, the equivalent circle diameter is calculated by Equation (1). De is used.

Next, the static mixer 1 constructed as described above.
A method for forming silver halide emulsion grains using No. 2 will be described.

From the first nozzle 34 formed at one end of the mixing chamber 20 and the second nozzle 36 formed at the other end thereof, a turbulent rectilinear flow A ₁ , A _{2 in which the} silver nitrate aqueous solution X and the halogen salt aqueous solution Y are opposed to _{each other.} As a result, it is jetted into the mixing chamber 20 having a cylinder diameter D ₁ which is larger than the orifice diameters D ₂ and D ₃ . As a result, in the mixing chamber 20, the eddy viscosity C due to the rectilinear flow A ₁ and the rectilinear flow A
_By causing the overlapped portion E of the eddy viscosities C and D to be maximized at the position where the eddy viscosity D due to ₂ becomes maximum, the two solutions are instantaneously mixed and reacted, and the mixed reaction solution Z is discharged. Eject from 26.

In the mixing reaction utilizing the eddy viscosities C and D, there are two methods for improving the mixing reactivity in the mixing chamber 20.

The first method is to inject the straight flows A ₁ and A ₂ in a thread-shaped high-speed flow so that the eddy viscosities C and D are instantly maximized in the narrowest possible range. . For this purpose, the first and second orifices 30 and 32 of the first and second nozzles 34 and 36 for ejecting the rectilinear flows A ₁ and A ₂ , respectively, are used to form the thread-like jet flow of FIG. The first and second orifices 30, 32 may be used.

From the viewpoint of mixing, it is preferable that the straight flows A ₁ and A ₂ are high-speed flows. However, in order to control the reaction product to have a desired particle size and size distribution, the liquid-liquid friction generated by the high-speed flow is used. The effect of frictional heat on the reaction must be considered. As such measures, the temperature of the reaction liquid is lowered in advance, or the addition pipe, the orifice portion, the mixing chamber portion, and the discharge portion are made into a double structure to be cooled, or both are used. Is effective. Further, the high-speed flow is determined by the ejection pressure applied according to the ejected flow rate and the inner diameters of the first and second orifices 30 and 32. Therefore, in order to create a higher-speed flow, the first and second The inner diameter of the orifices 30, 32 should be as small as possible to increase the pressure applied to the liquid. Therefore, although the wear of the first and second orifices 30 and 32 becomes a problem as the flow speed becomes higher, it is possible to deal with the problem by using a diamond or the like having high durability.

The second method is a method of increasing the liquid-liquid interfacial area formed by the rectilinear flows A ₁ and A ₂ by forming the rectilinear flows A ₁ and A ₂ in the form of a thin film jet flow. For this purpose, straight flow A ₁ , A ₂
As the first and second orifices 30 and 32 of the first and second nozzles 34 and 36 for ejecting the first and second nozzles 34 and 36, the first and second orifices forming the jet flow shape of the slit-shaped thin film or the fan-shaped thin film shown in FIGS. Two orifices 30, 32 are preferably used. Since this second method can secure a larger eddy viscosity region, good mixing performance can be achieved even if the jet velocities of the straight flows A ₁ and A ₂ are made smaller than those in the case of the thread-like jet flow shape. Can be obtained. Therefore, the wear resistance of the first and second orifices 30 and 32 is improved, and it becomes possible to manufacture the orifice from a metal, a metal-treated product, ceramics or the like having good workability, and at the same time, the straight flow A ₁ , A ₂ The generation of frictional heat can be suppressed by decreasing the flow velocity of the above, so that finer silver halide emulsion grains can be formed.

As described above, the static mixer 12 of the present invention is constructed on the basis of an idea which has not been found in the prior art. By using the static mixer 12, the following effects can be obtained. .

Since the static mixing device 12 has a structure for generating eddy viscosity, an optimum mixed reaction state in static mixing can be obtained, so that fine silver halide grains having good monodispersity are formed. be able to.

By carrying out the mixing reaction by utilizing the eddy viscosity, a good mixing performance can be obtained even if the jetting flow velocity of the halogen salt aqueous solution Y or the silver nitrate aqueous solution X is slowed down, so that the jetting pressure can be lowered. As a result, the ease of manufacturing the device, stability, and maintainability can be improved. Especially the first
Also, the material of the second orifices 30 and 32 can be changed to a material having a lower price and better workability than diamond.

By jetting the straight streams A ₁ and A ₂ in the form of a thin film, a mixed reaction of the halogen salt aqueous solution Y and the silver nitrate aqueous solution X at a high concentration becomes possible. This makes it possible to form seed grains of silver halide emulsion grains or to grow seed grains at a high concentration level that is industrially profitable. In particular, it is suitable for the formation of silver halide emulsion grains in a grain growth step in which a halogen salt aqueous solution Y and a silver nitrate aqueous solution X are mixed and reacted at a high concentration.

Further, by jetting the straight flow streams A ₁ and A ₂ in the form of a thin film, the jetting speed of the halogen salt aqueous solution Y and the silver nitrate aqueous solution X can be slowed down, so that the generation of frictional heat due to liquid-liquid friction can be suppressed. You can In particular, Ostwald ripening is less likely to occur during the formation of fine seed grains in the nucleation step, and silver halide emulsion grains having a smaller grain size can be formed.

[0056]

EXAMPLE (Example) The example is a test conducted by using the static mixer 12 shown in FIG.

That is, the static mixer 12 has a tube diameter of 3 m.
Mixer 2 having a mixing chamber 20 of m and 10 mm in length
A first nozzle 34 and a second nozzle 36 for ejecting turbulent rectilinear flows A ₁ and A ₂ are formed at one end side and the other end side of 2, respectively. The orifice diameter of both the first nozzle 34 and the second nozzle 36 is 0.2 mmφ,
A mol / L silver nitrate aqueous solution X was jetted at a jet flow velocity of 31.25 m / sec, and a 1.0 mol / L potassium bromide aqueous solution (containing 2% gelatin as a protective colloid) was jetted from the second nozzle 36 for 31.25 m. It jetted at a jet flow velocity of / sec.
Also. A discharge pipe 26 having a 1.2 mmφ discharge port was connected to the center of the mixer 22.

On the other hand, the comparative example is a test conducted by using the static mixing device for the T-shaped tube shown in FIG.

In the comparative example, the diameters of the first addition pipe 6 and the second addition pipe 7 were 1 mmφ, and the discharge pipe 9 was 1.5 mmφ. Then, 1.0 mol / L of silver nitrate aqueous solution X was jetted into the first addition pipe 6 at a jetting speed of 5 m / sec, and 1.0 mol / L of potassium bromide aqueous solution (2% as a protective colloid in the second addition pipe 7). (Containing gelatin) was jetted at a jet flow rate of 5 m / sec, and both liquids collided at the intersection 8 of the T-shaped pipe and discharged from the discharge pipe 9.

The silver halide emulsion grains formed by the static mixing apparatus of Examples and Comparative Examples were rapidly frozen in liquid nitrogen and the grain size was measured by an electron microscope.

As a result, the average grain size of the silver halide emulsion grains formed by the static mixer of the example was 8.6n.
m, and the coefficient of variation was 21%, indicating good monodispersibility.
On the other hand, the average grain size of the silver halide emulsion grains formed by the static mixer of Comparative Example was 18 nm, and the variation coefficient was 36%, which was larger than that of the Examples.

[0062]

As described above, according to the method and apparatus for forming silver halide emulsion grains of the present invention, the method for producing a silver halide light-sensitive material uses at least two jet streams in the mixing chamber. Even in the so-called "double jet method" that forms eddy viscosity, it is possible to reduce frictional heat when mixing an aqueous silver salt solution and an aqueous halogen salt solution, prevent cavitation, and efficiently perform a mixing reaction. Since the mixed state in the static mixing can be optimized, it was possible to form silver halide emulsion grains having a small grain size and excellent monodispersity.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a production line of a silver halide light-sensitive material equipped with a silver halide emulsion grain forming apparatus of the present invention.

FIG. 2 is a conceptual diagram showing a cross section of a static mixing device in a silver halide emulsion grain forming device of the present invention.

FIG. 3 is a schematic diagram illustrating eddy viscosity formed in a mixing chamber of a static mixing device.

FIG. 4 is a schematic diagram illustrating eddy viscosity formed in a mixing chamber of a static mixing device, in which the position of an orifice formed in a discharge pipe is changed.

FIG. 5 is an explanatory diagram illustrating the shape of an orifice that forms a thread-shaped jet flow shape.

FIG. 6 is an explanatory diagram illustrating the shape of an orifice forming a conical jet flow shape.

FIG. 7 is an explanatory view illustrating the shape of an orifice that forms a thin film-like slit-like jet flow shape.

FIG. 8 is an explanatory diagram illustrating the shape of an orifice that forms a thin fan-shaped jet flow shape.

FIG. 9 is an explanatory diagram illustrating a conventional T-tube type static mixing device.

FIG. 10 is an explanatory diagram for explaining a static mixer using eddy viscosity, which is a type of static mixer having a straight flow and a cross flow.

[Explanation of symbols]

10 ... Production line of silver halide photosensitive material, 12 ... Static mixing device, 16 ... Growth tank, 20 ... Mixing chamber, 22 ...
Mixer, 24 ... First conduit, 26 ... Discharge pipe, 28 ... Second
Conduit, 30 ... first orifice, 32 ... second orifice, 34 ... first nozzle, 36 ... second nozzle, 38 ... third orifice, A _1, A ₂ ... straight flow, C, D ... vortex Viscosity, X ... Silver nitrate aqueous solution, Y ... Halogen salt aqueous solution

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Fumiko Shiraishi             Fuji Photo, 210 Nakanuma, Minamiashigara City, Kanagawa Prefecture             Within Film Co., Ltd. (72) Inventor Nobuo Nishida             2410 Motoe, Uozu City, Toyama Prefecture Sugi Co., Ltd.             Inside the machine (72) Inventor Kenichi Harashima             2410 Motoe, Uozu City, Toyama Prefecture Sugi Co., Ltd.             Inside the machine F-term (reference) 2H023 BA01 BA07

Claims (4)

[Claims] 1. A silver salt aqueous solution and a halogen salt aqueous solution are jetted from respective nozzles into a mixing chamber having a diameter larger than the diameter of the nozzle to cause a mixing reaction, and the mixed reaction liquid is smaller than the diameter of the mixing chamber. A method of forming silver halide emulsion grains by discharging from a discharge port, wherein the silver salt aqueous solution and the halogen salt aqueous solution are at least two turbulent flows facing each other from one end and the other end of the mixing chamber. A method for forming silver halide emulsion grains, characterized in that the aqueous solution of silver salt and the aqueous solution of halogen salt are instantaneously mixed and reacted by being jetted as a straight flow into the mixing chamber. 2. The method for forming silver halide emulsion grains according to claim 1, wherein the jet flow velocities of the at least two straight-flowing streams are made equal to each other. 3. The method for forming silver halide emulsion grains according to claim 1, wherein the at least two straight streams are in the form of thin films. 4. A silver halide emulsion grain forming apparatus for forming a silver halide emulsion grain by mixing and reacting an aqueous silver salt solution and an aqueous halogen salt solution in a static mixing apparatus, wherein the static mixing apparatus is A mixer having a cylindrical mixing chamber in which the silver salt aqueous solution and the halogen salt aqueous solution are mixed and reacted, and a turbulent rectilinear flow of the silver salt aqueous solution from one end of the mixing chamber to the mixing chamber. And at least one first nozzle that is provided at the other end of the mixing chamber so as to face the first nozzle, and that jets the halogen salt aqueous solution as a turbulent rectilinear flow into the mixing chamber. A second nozzle and a discharge port for discharging the mixed reaction liquid which has been mixed and reacted in the mixing chamber from the mixing chamber, and the cylindrical diameter of the mixing chamber is larger than the diameters of the nozzle and the discharge port. It has a large diameter Forming apparatus of the silver halide emulsion grains, characterized in that.