DE2114223A1 - Process for the preparation of dispersions - Google Patents

Description

21H223

AGFA-GEVAEET AG

March 22, 1971

Process for the preparation of dispersions.

Priority: Great Britain, April 1970, note no. 15 9 ^ 8/70 Gevaert-Agfa N.V., Mortsel, Belgium.

This invention relates to a method for making dispersions by means of liquids mixed in a flow passage.

This invention is in the course of research relating to the Manufacture of photosensitive silver halide dispersions made but is also applicable to the formation of other dispersions, either of one liquid in another (emulsion) or of a solid in a liquid (suspension).

There are several methods of mixing fluids thoroughly Materials have been proposed, but for certain purposes the known methods do not give a sufficiently uniform mixture.

As broadly defined, this invention is based on a method for mixing or more thorough mixing of liquids, characterized in that the liquids to be mixed or more thoroughly mixed Liquids are introduced in a continuous manner in a flow passage, over the entire cross section of the supplied Liquids are carried away in continuous motion from the feed point or points, and within which flow passage the flowing liquid mass is subjected to forces that cause turbulence in them

This method can be used, for example, to reduce the dimensions of the dispersed droplets of an emulsion.

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Another and particularly important field of application of the invention is the formation of dispersions, either emulsions or suspensions, by mixing liquids of such a nature that the mixing causes the formation of a disperse phase. this is the Case when different liquids are mixed that contain one or more dissolved ingredients * which are chemically or physically react and form a product which is a disperse phase in the mixed liquid mass. For example a liquid containing a dissolved substance, which with a change in pH the liquid precipitates, and the other liquid an ingredient that causes such a pH change «Another Example is that one liquid contains a dissolved substance and the other contains a liquid that corresponds to the first liquid is miscible, but a non-solvent for such substances is. The various liquids can also contain dissolved ingredients, which cause a solid precipitate to form react, e.g. in the form of crystal grains. An example of such a process is the formation of silver halide grains Reaction of a soluble silver salt and a soluble halide »

It is an important feature of this invention that the the starting material constituting fluids continuously from the feed point or flow away from the feed points, although thrust> forces arise everywhere in the liquid space. As a result of this ■ ■ « Conditions will be the amounts of liquid which are in any given Flow into the passage for a moment, not with material mix that has already been subjected to shear forces in the passage. This is of particular importance in the manufacture of Dispersions, in which it is desired, the size of the dispersed To keep droplets or particles within certain limits, and especially in the preparation of suspensions through a disperse phase of small grains are characterized, because the described circumstances help that after the formation of these Droplets or particles in the passage that connects the dispersed droplets or particles grow by coming into contact with new reagents

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In the case of chemical precipitation reactions, the different Liquids, the mixing of which causes the formation of the precipitate, continuously and separately introduced into the mixing passage will. Preferably, the cross-sectional dimensions of the mixing passage and the degree of turbulence are such that those in each Reagents entering the passage instantly are almost entirely used up for nucleation and in no noticeable degree for grain growth will. This means that only small amounts of liquid are brought together in the mixing passage at any given moment. Experiments have shown that, in order to achieve this result, the mixing passage generally has a very small cross-section that allows a liquid film less than 5 mm thick to flow through «

As shown in the following examples, this leads to Carrying out precipitation reactions according to this invention in general to a grain size division with a logarithmic Course which is in contrast to the bell-shaped distribution curve (Gaussian distribution) obtained when silver halide emulsions be formed by the conventional batch process.

As this invention progresses, it becomes of value placed on embodiments in which the liquid is in the Mixing passage is in turbulent flow.

An important fact about turbulent flow is that when the Local forces acting on the liquid in the liquid flow Eddy currents, which are responsible for a large increase in the resistance to movement, cause the fluid has an average forward velocity component at each point, i.e. a velocity component in the Direction in which the liquid flows through the passage. The mean, forward speed components on the different points within the stream result in a well-defined, predictable velocity profile. Consequently, the material when it is in the form of a thin film in a turbulent flow

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- if -

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Mixture passage flows through, a uniform and predictable Subjected to mixing effect, which is due to shear forces everywhere or in almost all parts of a volume. This is clear Contrasted with the effect after which within an amount of liquid For example, a mere turbulence is created by means of a propeller.

The transition from laminar to turbulent flow is made possible by the Reynolds number determined; it is the critical value that im Moment of transition the ratio of the energy (erg in the c.g.s. system) necessary to obtain a velocity ν (cm per sec.) of the moving liquid mass results in the energy consumed in the friction.

Specifically, the Reynolds number (Re) is obtained from the following relationship calculated :

in which:

1 = the diameter (in cm) of the flow cross-section, e.g. the diameter of a pipe,

ν = the flow rate of the liquid mass (cm per second), u = the density of the liquid mass (gram mass per cm3), Jj = the dynamic viscosity (dyne.Sec.cm).

The critical Re value at which a flow becomes turbulent should experimentally for each type of liquid and for each type of passage to be determined.

For example, if water is introduced into the slot-shaped passage between two cylinders with a smooth surface, which by a clearance equal to r ₂ - r. are separated between the larger and the smaller cylinder, this margin in comparison with the respective radii r ₂ and r. is relatively small, and the larger cylinder rotates and the smaller cylinder is stationary, the critical Reynolds number is 1900. If, however, the inner cylinder rotates and the outer cylinder is stationary, one obtains a turbulent flow with a much lower tangential one

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Speed. The conditions for a transition from laminar on turbulent flow in a similar system have been determined theoretically and in practical experiments by G.I.Taylor, Phil. Trans. (A) _22J> (1923) p.317 has been confirmed.

Re =

in which:

II = the critical daily speed of the inner cylinder, c = the clearance between the cylinders,

_ ji _ k kinematic viscosity
k ~ u ~ density

r = the mean vert of the radii r "and r_ of the inner or the

outer cylinder, and
d = P ₂ T ₁

The turbulence that is obtained at all points of the liquid mass which at any moment fills the mixture passage can be produced by exerting on the liquid in the direction of flow a pressure sufficient to the Reynolds number to keep noticeably above the critical value at which conditions of turbulent flow occur and / or by one Wall or more walls of the passage moved at a speed that is necessary for the generation of a turbulent flow by friction sufficient. It is currently preferred to design the mixing passage through walls which are capable of generating such frictional forces are continuously rotated relative to each other about an axis.

The mixing passage may be in the form of a sheet or a film, and even this form is preferred. The thickness of this layered space is preferably less than 5 mm at all of its points or at least in part thereof. As will be shown in the following, the thickness of the layered space need not be uniform.

Such a layered space can, for example, be divided by two Plates ζ · Β. Slices are limited, of which at least one with respect to the other rotates at high speed (ζ · Β. with 10,000 or 20,000 rpm ·) · The layered space between the For example, panels can be about 0.05 mm thick. The panels can

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for example, disks with a diameter of 50 cm or less. Larger diameters are not excluded, but cause unnecessarily high centrifugal forces »

According to the preferred embodiments of this invention, the mixing passage has the shape of an annular space which is determined by opposing surfaces of rotation - the liquid in this passage becomes more turbulent, wholly or mainly by frictional forces, which are caused by relative rotations of such surfaces about their common axis of rotation Flow kept. The surfaces delimiting the passage can be flat, or one of them can be helically grooved, but so that the liquid in the groove or grooves should not be shielded from the tangential thrust forces, the inclination of the groove or each groove should be greater as h5 °. Devices of this type can, for example, have a body which is rotatable within a radially symmetrical space which is delimited by an enveloping housing and thus defines an annular space which can be kept filled with liquid material by continuously inserting this material at one end into the annular space and also continuously discharges liquid at the other end of this space at a coincident rate, while the inner body is kept rotating at a rate sufficient to above the Reynolds number which coincides with the fluid flow along such space the critical value at which turbulence occurs. Of course, the frictional forces required to generate the turbulence can be generated by rotating the housing with respect to the inner body instead of the other way round, or by rotating the inner body and the housing in opposite directions. The forces required to create the turbulence can, if desired, be partially realized by introducing the liquid material under pressure into the annular passage, in which case the relative speed of rotation of the inner body and the housing can be reduced accordingly ^. In general, however, it is preferred , the liquid

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Introduce material into the annular space by gravity, because the delivery system can then be designed very simply · The inner and outer body can be cylindrical, or one or both have a diameter along their axial dimension can preferably vary in such a way that the thickness of the annular space can decrease towards its end which end the mixed liquid materials are drained. So the inside diameter of the housing can remain constant or decrease while the outer diameter of the inner body increases, or both diameters can increase in different proportions, or the outer diameter of the inner body remains constant, while the inner diameter of the housing decreases · Preferably but the internal profile of the housing and the external profile of the inner body taper towards the vent end, making the annular Space decreases after this end of drainage. In all of these embodiments, the inner body can be coaxial or eccentric in With respect to the housing, but preferably the housing and the inner body are radially symmetrical and coaxial.

The facing surfaces, which determine the layered space, can be smooth or raw and / or have protuberances which promote the generation of the desired turbulence. the Turbulence can sometimes be promoted by designing or using the equipment so that the liquid is in the mixing passage Is subjected to frictional forces which are a result of the relative movement of the walls defining the layered space, and their size and / or direction depending on the point under consideration vary the flow path of the liquid. In the case of a disc device, the tangential thrust forces take in the direction of the The periphery of the poor-looking room. In the case of a device, that creates an annular space between the inner and outer bodies rotating relative to one another, can be a change the! initial speed and the tangential shear forces take place, by reducing the cross-section of the annular space. There may be less or more sharp changes in angular velocity caused by the speed of the relative rotation of the disks or of the other bodies which form the layered

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Determine the hem, varies. Additionally or as an alternative you can use the Direction of rotation of the body or of each body during the flow any amount of liquid material through the layered The space between the bodies can change, and / or one or each body can be moved in a direction parallel to the feed-discharge flow direction vibrating · In the manufacture of silver halide grains, it is preferable to use a continuous mixer Flow that has a central inner body (rotor) and an outer body (Housing), which envelops the jacket surface of the rotor, contains, and are arranged in the housing and rotor coaxially, and a clearance or layered space in the form of an annular passage which has a continuously decreasing cross-section perpendicular to the axis of rotation · The larger cross-section of this layer-shaped Space serves as an inlet opening for the mixing zone, which is between the casing of the rotor and the surrounding surface of the housing is formed, and in its smaller cross-section serves as a discharge opening for the mixing zone · The opposite walls »which the Determine layered space are imperforate, smooth or helical grooved or are raw and / or have point-like protuberances, which in a liquid that is forced through To flow this clearance, the formation of turbulence promotes, the rotor and / or the housing with moving devices for its or «their rotating movement around this axis are provided · In this device, the housing expands from the zone of larger cross-sections goes away, preferably in the extension with the axis of rotation above the rotor, and the top surface of the rotor in the zone of the larger cross-sections preferably has the shape of a cone, the summit of which is directed upwards, and its. Surface is smooth.

The invention is of particular importance for the manufacture of photosensitive ones Silver halide emulsions. Various other types of reactions which involve the formation of dispersions and precipitates bring themselves, and for which the invention can be used advantageously, are illustrated by means of examples.

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In the preparation of silver halide emulsions, the invention has benefits in addition to promoting the formation of silver halide grains with a narrow grain size distribution, the important potential advantage, that silver halide grains with an extremely small average size can be formed

The size of the silver halide grains formed in such emulsions will depend on a number of different factors. These factors include the concentration in the solutions of the soluble salts that are allowed to react with a view to the formation of the silver halide precipitate, the pH and the temperature of the reaction mixture, the amount of gelatin or other protective colloids present in this mixture, the presence or Absence of crystallization nuclei and / or retarders of grain growth, and the pAg value of the reaction medium in which the silver halide precipitates, the latter value depending on the relative amounts of silver and halide xones in the reaction mixture · The way in which these factors individually determine the silver halide grain size influence is known per se. So for example it is well known ι that while retaining the other factors, the silver halide grains will be smaller, depending on the pAg value of the reaction medium, which is determined by the excess of silver ions over halide, or vice versa, approaches a value at which the Silver halide solubility is minimal, ie at a pAg value between 2.5 and 3> 5 or between 7.5 and 8.5

According to standard practice, the smallest achievable is average Silver halide grain size in silver halide emulsion production approx. 0.05 micron * These fine-grained emulsions are the so-called Lippman emulsions, during their manufacture grain growth retardants are used. Such micrograin emulsions are useful in making photographic plates or films with high resolution, for example for microphotography, astrophotography, the recording of nuclear physical processes, mask production in Production of microelectronic integrated circuits, and

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for the recording and reproduction of holographic signals or Radiation interference or refraction patterns

On condition that the procurement of the reaction mixture and its temperature can be chosen so that the formation of the smallest possible Silver halide grains are promoted, it is through Mixing of the reagents according to a method according to that described above Invention possible to form silver halide emulsion, the silver halide with an average grain size considerably below 0.05 microns included. The grain size tends to get smaller, depending on the shear forces exerted by the reaction mixture exposed to increase «It is easily possible) a turbulent To create a flow in which the thrust forces are such that the silver halide grains in the emulsion drained from the mixing passage have an average size of less than 0.03 microns

The following should be said of the attached drawings:

Figures 1 to 8 and 11 to 13 are schematic cross-sections of FIG Continuous flow thin film reactors, which are suitable for the use according to the present invention are suitable

Figures 9 and 10 show different types of Botort for the Device shown in Figure 8

Figure 14 is a cross section of a thin film reactor with continuous Flow of a type similar to that shown in Figure 8

Figure 15 shows a particular form of inlet system for use in emulsification (precipitation) in the preparation of a photographic silver halide emulsion using mixing equipment such as shown in Figure 14 used

Figure 16 is a flow chart showing the electronic measurement and Control systems for regulating the feeding of photographic silver halide Represents ingredients.

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Figure 17 is a flow diagram that the continuous production illustrated by photosensitive silver halide casting compositions

Figures 18 and 19 are grain size distribution curves of silver halide dispersions, which have been made in accordance with this invention.

FIGS. 20 and 21 are cross-sections of mixing devices which work according to the principles which are based on FIGS. 1 and 2, respectively are described.

Figures 22 to 28 are curves showing the experimental results which is written about in Examples 4 to 9.

Figure 29 is a schematic cross section of another reactor for use in practicing this invention.

In the figure 1 is a device for the continuous flow mixing in a circular; slot-like passage illustrated. The device comprises a disk 1 which is rotatably mounted and parallel to a table 2 which is fixed in a housing 3. The shaft 4 of the disk 1 is hollow and serves to allow the disk to rotate relative to the table 2 by means of a suitable drive means, for example an electric motor (not shown), and at the same time serves as a supply line for a liquid A, which contains the desired reagent, for example Contains silver nitrate for the production of the solid particles. In the center of the table 2 there is another feed opening 4 through which a liquid B containing the necessary reagents, for example a water-soluble halide, is introduced. The dispersion obtained is discharged through an annular outlet opening- 5.

In Figure 2 a device is shown which is similar to the device of Figure 1, but in which two discs are arranged which rotate in opposite directions. Liquids -A and B are introduced through the hollow shaft h of the disk 1 and through the hollow shaft 6 of the disk 7. The dispersion is drained through an opening 5 in the housing 3.

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The device shown in FIG. 3 is the one illustrated in FIG similar, but the turntable 1 has a conical shape and forms with the fixed table 2 an annular passage, the cross-section of which narrows from the center to the periphery of the rotating body.

The device of Figure k is similar to that shown in Figure 2, but the shape of the turntables is such that they have opposing conical surfaces forming an annular passage the thickness of which decreases from the center towards the periphery.

The device shown in Figure 5 comprises a body in the form a ball 8, which is rotatable in a hollow ball 9 with coaxial inlet openings 10 and 11 and a single outlet opening 12 is arranged. The passage between the body and the ball 9 is shown from top to bottom with constant thickness, however the ball 8 can be mounted in such a way that the passage has a variable thickness, ζ · Β. such that he is at the inlet ports 10 and 11 are wider than the drain port 12.

In the device of FIG. 6, a conical body 13 is mounted to pivot about an axis in a conical housing "\ h , the inner diameter of which increases from the summit inlet of the mixing passage to the bottom drain opening thereof. The reagents are introduced through separate inlet openings 15 and 16 and drained through a single annular opening 17.

The device of Figure 7 comprises two separately rotatable bodies 18 and 19, which are driven by electric motors 20 and 21, respectively. The speeds of these motors are continuously adjustable and the body sin'd 18 and 19 can be in the same or opposite directions turn. With this device it is possible to measure the tangential speed and to continuously change the angular velocity. The reagents are through separate inlet openings 15 and 16 at Summit of a housing 120 inserted and through the only drainage opening * 17 drained.

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Instead of driving the bodies 18 and 19 by separate electric motors, these bodies can be designed as the rotor of an electric motor and thus the necessary armature components, e.g. Guiding elements and / or carry or contain magnetic poles. The housing 120 is then provided with a number of pole pairs which surround its inner circle are arranged with gaps opposite the poles or the electrical armature of the rotor. The inner wall of the case and the Outer walls of the rotating body are preferably made of an insulating material or covered with it, for example covered with polytetrafluoroethylene · The magnetic flux lines traverse the liquids to be mixed and the charged particles or ions that are present in these liquids can influence according to known magnetohydrodynamic principles.

The continuous flow film reactor shown in FIG contains a disc 1, which is mounted in parallel to a table 2, which is part of the housing 3, rotatably. The disk is driven at high speed (up to 20,000 rpm) by means of an electric turbine motor 102. Of the Disk diameter is preferably not larger than 50 cm, so that the tangential speed at its periphery is approximately 500 m / sec. can be. The distance between disc 1 and table 2 can be changed here by means of a calibrated plate 103 or calibrated plates, which is or are arranged between a hexagon nut and the washer 1.

Liquids A and B are introduced through lines 105 and 106 and through the center of table 2. The housing 3 is with a side opening 10? Mistake.

The continuous flow film reactor shown in Figure 21 includes two disks 108 and 109 which are in opposite directions Directions with drive belt 110 and 111 driven on pulley ^ 112 and 113 · The to form the dispersion Liquids used A and B are through lines 11 ^ and 115 and initiated through the center of the discs. The food-

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Lines are provided with the necessary sightings 116 with a view to a seepage-free rotation of the lines. The housing 117 is provided with a drain opening 11S * Bze disc 108 is adjustable with a rack gear 119-120, which can be locked in any position by the locking device 121. The bearing 122 for the hollow axle 123 is lubricated under pressure with oil, which enters the thrust bearing through the line 12%.

Figure 29 shows another continuous flow mixer in accordance with this invention. This device consists of solid parts and the turbulence in the mixing passage is created by placing the liquids under sufficient Presses pressure into the device.

The device comprises inlet tubes 125 and 125 ', which according to the Pipes 126 and 126 'lead, which are in mutual extension and are in communication with the central mixing pipe 127. the Pipes 126 and 126 »are with bushes. 128 and 128 '.

According to one embodiment of the invention, two substances that are associated with must react to each other, introduced through the pipes 125 and 125 ', while a carrier liquid also serving as a diluent is continuously pressed through tubes 126 and 126 'and nozzles 128 and 128'. The carrier liquid is under controlled Pressure (p) and supplied at a speed (V). The pipes

126 and 126 'terminate in communication with the mixing tube 127 in. a kind of rocket propulsion nozzle "

The liquids containing the reagents are in the tube

127 due to the high speed and turbulence which is caused by the frictional contact with the pipe walls is caused, and vigorously mixed by the impact of the liquid streams moving in opposite directions.

According to a second embodiment, a gas is passed through the nozzles

128 and 128 · initiated, and become different liquids introduced through feeder tubes 125 and 125 ». It forms in the tubes 126 and 126 'some kind of foam. In the mixing tube 127

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finds a thorough mix under conditions of whirling motion the foam masses instead.

For mixing more than two liquids, more than two feed lines such as 126 and 126 'are used · So is For example, it is possible to have a number of tubes such as 126 and 126 'like the spokes of a wheel, which are connected to a central mixing tube like 12? are connected to arrange.

Instead of arranging the tubes 126 and 126 in a diametrical position, they are tangential with a thin-film mixing chamber, which is connected with a mixing tube like 12? is provided, connect.

The mixing device shown in FIG. 8 contains a conical rotor 1 which is driven by a shaft 2 which is connected, for example, to an electric motor. The rotor 1 rotates in a conical chamber 3 «. The clearance (c) between the rotor 1 and the chamber can be adjusted with a regulating device and the screw k. The ingredients required to form a dispersion, for example through a chemical reaction, through emulsification, salting out or crystallization, are admitted through separate inlet openings and pipes 5 into the funnel 6, which is the upper part of the device. The mixture formed or the reaction products are fed through a Pipe 7 drained

The upper part of the chamber 3 can be left open as shown or, if desired, can be closed light-tight depending on the process to be carried out.

The angles α and β shown in FIG. 8 should not necessarily be of the same size. The angle y can vary, for example, between 0 and 90 °. The part of the rotatable body located inside the funnel 6 does not necessarily have to be conical.

The diameters 0 * and 0 ~ and the heights (h.) And (hp) are selected depending on the desired mixing time and the degree of mixing achieved.
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Masstäbliche laboratory models may, for example, rotors having a height of 20 cm and have a diameter cm 0 * of the tenth Large-scale mixing devices can have a rotor with a height of approximately 100 cm and a diameter JÖ of approximately 50 cm.

The diameter JZL of the rotor at the discharge opening can be very small be provided that the mechanical strength of the base of the rotor is sufficiently large and its required balance remains possible.

The mixing device according to FIG. 8 is normally operated in a vertical position, so that gravity supports the flow of the liquid material after the discharge opening of the annular mixing passage. However, the device can be used in an inclined or even in a horizontal position. In the latter case, the rotor or d-le rotating chamber preferably has a helical profile at the surface for conveying the mixture to the vent opening.

For example, if the device is viewed in a vertical position of action is, the ingredients to be mixed in the liquid phase in a controlled ratio continuously through the openings 5 and fed continuously into the annular mixing passage drained between rotor 1 and chamber 3. The liquid materials flow in a helical path within said annular mixing passage down under the combined influence of gravity and frictional forces on the liquid, which are due to the high speed of rotation of the rotor 1. While the liquid materials pass through vigorously the shear forces created by the greater part of the liquid in the passage are mixed, with the whole amount of liquid in turbulent motion, there are only very small amounts of liquid in any one Instantly in contact with each other in the feeding part of the mixing passage. Such crowds are always being forced to away from the "inlet and toward the outlet opening.

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As a result, the reagents in such small amounts of liquid are entirely used for nucleation and not, or almost not to a considerable extent, for grain growth. The significance of these features is evident from the fact that when the reagents are added in such a ratio that they overflow and contact each other more above the reactor than within the annular passage, the result is an increase in the mean grain size of the silver halide It should be noted that if a rotor is used which does not have a helical fluid-conveying profile, the speed of rotation and the clearance between the rotor and the chamber should be such that effective friction and turbulent flow of the ingredients nevertheless take place · According to a preferred embodiment, this is the reason why the cross-section of the annular passage between the chamber 3 and the rotor is made variable by the arrangement of a control device k.

With reference to FIG. 8, it goes without saying that the rotor and the inner wall of the housing do not have to be conical and can have the shape of any other geometric body of revolution with a tapering diameter. The rotor body can, for example, have the shape of a section of a parabola, a hyperbola or an ellipse * In such cases the rotor diameter can decrease from the diameter JZi to the diameter JZL.

According to another embodiment, a rotor is used, the one generally conical in shape but with a helical circumferential groove with constant or variable rate. The peaks and the grooves can, for example, be conical, right-angled, be sinusoidal, semicircular, etc. *

Two different shapes of helically profiled rotors, which can be used in a housing as shown in FIG. 8 are shown in FIGS. In the case of the rotor 1 in FIG. 9, this has a helical shape Provided groove, the depth of which is infinitely variable according to the The discharge end of the rotor decreases while the rotor diameter decreases

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measured at the bottom of the groove, remains constant. The eotor shown in Figure 10 has a generally conical shape and is tapered towards the outlet end both along the thread crest and along the bottom of the thread groove · Along the taper angles the summit and along the bottom of the thread groove can be the same or different, so that the depth of the helical Exile remains constant or gradual depending on the case under consideration varies.

Instead of displacing the fluids by putting an eotor in a fixed chamber or «rotates in a fixed housing, it is possible» the liquids follow a »helical path by rotating only the chamber or the chamber and the Eotor at different angular speeds or in opposite directions Directions rotated. Ik considering the simplicity of construction and the. Mixing efficiency is preferred to one Device with a rotatable Irmenkörper and a fixed Housing to use.

Other devices for use in practicing the present invention are shown in Figures 11, 12, and 13. Denoted by numbers 1, 2, 3, 6, and ? Elements designated fulfill the same function as those indicated by the numbers in FIG.

Figure 1A is a more detailed drawing of an laboratory mixer, which is suitable for practicing the present invention, particularly in continuous manufacture photographic silver halide emulsions * Der Botor 21 is of the threaded conical! yps «Die den Eotor surrounding chamber 3 is provided with a heating * or cooling jacket 8, which has an inlet opening 9 and an outlet opening 10 for a heating liquid, steam or a coolant · As an alternative you can also heat electrically «

The clearance between the chamber 3 and the rotor 1 is provided with a centrally located screw * t, which reduces the friction of the rotor

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reducing ball 11 carries, variable. The electric motor 1 is driven by an electric motor 12 which is connected to a shaft 2 which enables the rotor 1 to be adjusted vertically. The mixing device has a bottom discharge opening 7 and at least one feed line 5 for introducing the ingredients to be mixed. The upper part 6 of the chamber is provided with a cooler 13 which is pneumatically or electrically operated. For example, the sensor contains an electrically insulating drill which contains two electrically conductive needles which make electrical contact with the liquid materials in the mixing device when they reach a predetermined level. The resulting electrical signal (control signal) is transmitted to the speed controller or the gear pump or another metering device, which regulates the supply of ingredients, and / or is transmitted to the speed controller of the helical grooved rotor 1 to increase the rotor speed, so that the flow rate of the liquid Materials is adjusted and the liquid does not rise above said predetermined level.

The clearance between the chamber 3 and the rotor 1 is normally kept constant in one and the same mixing process and can be adjusted if factors such as the viscosity, the efficiency of the mixing process, the reaction speed, the heat transfer in the quantities of liquid to be mixed within a certain period are taken into account considered. The efficiency of the mixing process increases inversely proportionally with the latitude, so that the so-called thin film mixing with the mixing device with a latitude between the outer surface parts of the rotor and the chamber wall of preferably 2 mm in scale laboratory models (rotor height 20 cm) and of no more than 10 mm in large-scale industrial models (Eotor height 100 cm) , is preferred. The clearance is preferably variable between 0.01 and 10 mm.

To explain the continuous precipitation of silver halide in the production of photographic silver halide emulsions according to 15 and 16 of the present invention is particularly referred to pointed out

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FIG. 15 shows a special inlet system for the silver halide precipitation shown, which is to be regarded as a modification of the inlet system shown in Figure 1 ^.

According to FIG. 15, the inlet system contains three separate supply lines 14, 15 and 16, which are provided with magnetic valves 17, 18 and 19, respectively are provided. Except for the inlet system, the mixer is the same as that shown in Figure 14 including one Shell 8 for heating or cooling gas or liquid, preferably steam or water. The dispersion formed in the mixer is drained through line 7 (Figure 1 * l ·) with a thermometer and electrodes as shown in FIG. For the effect in a vertical position this will be Mixing device provided with a support frame not shown in the drawing.

An aqueous silver nitrate solution and an aqueous solution of gelatin and a water-soluble halide, e.g., potassium bromide and sodium chloride, are processed separately in a controlled ratio the lines 14 and 15 supplied.

Line 16 is used for adding special ingredients if necessary or pH regulating compounds are used in the emulsification mixture. This line can be used e.g. for the introduction of a aqueous solution of ammonia and acetic acid and other substances which affect the pH value and grain growth.

The temperature of the reaction mass can be achieved in view of the Result can be varied within wide limits, but is normally kept below 80 ° during the silver halide precipitation.

Gravity and / or pressure, e.g. atmospheric pressure, determine the rotor speed, the rotor profile and the wall of the inner chamber, and the clearance between the rotor and the chamber wall the transit time through the mixer.

Since the ..flow of the liquid mass in the annular passage is highly turbulent around the rotor, there will be rapid contact

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between the reagents contained in a thin film of liquid and not secured in a large mass as in a batch process. At every moment there are only very small ones Quantities of reagents allowed to come into contact with each other The products obtained are drained continuously and quickly from the mixer

Silver halide formation is a quick chemical reaction and it goes continuously forward in the mixer so that large quantities of reproducible silver halide grains can be produced in a relatively short time Quality is preserved

The reagents are mixed vigorously under conditions similar to a allow excellent temperature control without the need to use a substantial excess of any of the reagents · The contact small amounts of reagents in short contact periods (e.g. from a fraction of a second to a few seconds) and the rapid removal of the reaction products from the turbulent Flow in the thin film mixer make it possible to produce silver halide emulsions with narrow grain size distribution and very small grain size, for example to produce below 100 nm and even below 30 mn

Silver halide precipitation can be used to achieve very reproducible results electronically control and regulate with signals obtained through continuous measurement, as shown in the figure 16 will be described. The discharge tube 7 of the thin film reactor is equipped with a glass electrode 20 (pH control), a silver electrode 21 (pAg control) and an ordinary thermostabilized one Reference calomel electrode 22 is provided. The latter electrode has a saturated potassium nitrate bridge 23 (which contains the potassium nitrate for example absorbed in agar-agar) connected to the emulsion flow

The potential difference between the glass electrode 20 and the calomel electrode 22 is fed to an electronic potentiometer Zh, calibrated in pH units. The one between the silver electrode 21

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and the potential difference obtained on the calomel electrode 22 is fed to an electronic potentiometer 25 which provides millivolt readings from which the pAg values can be calculated. The amounts of compounds such as acetic acid and water-soluble halide for correcting the pE and pAg values are controlled by magnetic valves 30 and 31, which are connected to two process controllers 26 and 27, respectively, and are adjusted to a predetermined pH or pAg value. Maintain value. The output signal of the potentiometers Zk and 25 is fed to these process controllers 26 and 27, and the difference signal is used to control the magnetic valves 30 and 31. The electronic signals that correspond to the pAg and pH measurements are fed to a writing galvanometer 32 so that a continuous diagram of the ρ Ag and pH course during the precipitation is obtained.

The temperature which is reproducible in terms of obtaining Results must be kept constant, can be measured at the drain opening with a resistance thermometer, and the output signal with a preset control signal in a differential -Potential -measuring transducers compared. When the desired temper aturbedinguagea prevail is the difference between the two signals zero · The difference signal is used, for example, to control a needle valve in a steam supply line for the heating jacket of the conical mixing device or the speed of the motor, which is connected to a gear pump, which is a liquid coolant is pumped into the jacket to control · The discharge opening of the mixer can also be equipped with measuring devices for turbidity, spectral absorption and / or conductivity the liquid flowing through.

The inventive method can be used for the production of all types photographic emulsions can be used, for example, neutral, acidic and ammoniacal emulsions, and according to a preset program adapted to different Ejnulgiejrsiethoden will. The way in which the ingredients are added, the emulsification rate, the emulsification temperature and the excess of the

GV. h 61

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the halides, either in uniform or in decreasing amounts, can easily be modified or varied. The usual way of designating the amount of halide in emulsion production is by the percentage excess over the amount equivalent to the silver. Teodobromide emulsions usually contain between 20 and 250 % excess bromide during precipitation and ripening. Chlorobromide and chloride emulsions rarely contain more than about 10 % excess halide, and the latter can be as low as 1 to 2% in cases where very little grain growth is desired.

Any ammonia used can be introduced into the silver nitrate solution, where silver oxide initially precipitates out with further addition of ammonia dissolves and a solution of a complex Ammins surrenders. The ammonia can also be incorporated into the gelatin halide solution.

When an ammoniacal emulsion is made, the pH is of the precipitation mixture largely due to the addition of aomonia, but in other emulsions the pH can be critical during the precipitation and should therefore be carefully regulated, viz with a view to producing small silver halide comers.

The ratio of the different halides in the silver halide crystal and the order of their addition can be easily controlled and distributed, for example, through two or more mixing devices arranged in series. For example, you can easily Types of composite grain emulsions are obtained as described, inter alia, in British patent specification 1,027,16. According to The latter process is first a fine grain emulsion. with narrower Grain size distribution established. After the interruption of the Precipitation is chemically ripened, whereupon the precipitation is continued. In this way, an emulsion is obtained, the silver halide of which consists of a chemically ripened core, which is replaced by a Layer of unripened silver halide is coated.

Mixing by turbulent flow in the form of a thin GV.461

109852/1927

Schielit gesilles öisse? Invention is also suitable for manufacture; iron Silberh & Loge & idemuleioaen, von- der Eis Seil © eier alles Silber- '-

cl®a ^: @ af & i, gMcSa "formed silver halide grains öuroh a type iroa silver dialogues or" has been converted ο so kmaa, for example, the silver eliloridaate part be replaced by a bromide component, oto © that the Kora size is stored ".

Halogeaide siad Kalium uad Affimoaium, but also cations from Srdalltaliiaetailsalsen like calcium chloride or aosh other soluble metal halides are used in the Isulsionaheretelliaag · These can be used with regard to Speaialeffekt © &&? Baulsion either ia grossea oä & r kleiaea Meagea incorporated *?

Various measures can be taken to delay the grain growth. For example, silver halides formed during the precipitation are known to be finer with the minimal solubility of the silver oxide when the gelatine concentration has been increased to a certain level, when the temperature is above the solidification point of the gelatine and preferably between $ 0 and 40 °, or if there are crystallization nuclei such as silver iodide or silver sulfide

It is also possible to retard grain growth by means of chemical compounds, for example imidazoles, thiazoles, thiolactic acid, 1-phenyl-5-mercaptotetrazole, nucleic acid, thiosulfate, cystine, ehioglycolic acid, and dithiopyrifflidine. These compounds, which prevent or retard grain growth, can be added during the precipitation or added to the silver halide dispersion after it has left the mixing device with turbulent flow a * It is very important that when a silver halide emulsion is produced in a mixing device with turbulent flow according to TorliQ ^ eaäei · fefia € umg under the conditions, di © geeigaat are m & I feiakSrnig © Skulsionea zu eraieleu ,, di © Mwee ^ nheit öss la Buaafilfflra, ¹ »» ataf die Gross © öss? ISi

109852/1927

ORIGINAL INSPECTED

It seems to have little or no influence, but that the grain growth retarder should be added to the emulsion as soon as it is no longer subject to the mixing conditions of the turbulent thin-film flow i.e. immediately after leaving the mixer. It is therefore sufficient to add a retarder to the emulsion if the latter leaves the mixer.

Other useful Kornwachstumverzögerer are the ü in British Patent? 6i 875 mercaptotetrazole compounds, heterocyclic compounds and mercapto compounds which f in the American patents 2 K3Z 506 and 2 KJZ 86 ^ described in French Patents 1,557,289, Belgian Patent 710 602 and 723 ^ 92 and in the German patent applications 20 53023 * 8 and 20 53961 * 1. The following may also be mentioned as grain growth retarders: sulfonated heterocyclic mercapto compounds, ζ · Β. 2-mercapto-5-sulfobenzoxazole, 2-mercapto-8-sulfonaphthoxazole and 2-mercapto-5-chloro-7-sulfobenzoxazole, selenium compounds ζ · Β. the diselenides described in Belgian patent 7 ^ 7 012, for example diphenyl diselenide and ρ, ρ'-dichlorodiphenyl diselenide. It is preferred to use grain growth retardants containing aromatic nuclei.

When the invention is applied to silver halide emulsion preparation it is of course not limited to the production of fine grain emulsions. It is also possible and for Various purposes are desired to ripen the emulsion discharged from the turbulent flow mixing passage. This ripening can be carried out without having the advantage of a uniform emulsion with a narrow grain size distribution loses. In fact, through physical ripening, the grain size distribution can be made even narrower. It can be broad Grain size distribution can be achieved by performing the precipitation on existing grains, for example by the initially produced grains are circulated again, or a further precipitation in one or more jointly connected mixing devices undertakes, into which one introduces the emulsion initially prepared.

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The flow diagram shown in FIG. 17 shows the continuous production of photosensitive silver halide emulsions, after a number of mixing devices with turbulent thin-film flow according to FIG. 14 can be used.

The production begins with the precipitation of silver halide grains in a heatable and thermostabilizable mixing device 41 at a given temperature T. The device is provided with two separate supply lines 42 and 43, one for the aqueous solution of the silver nitrate and the other for the desired halide and the protective colloid, which is usually gelatin. The feed is made at a speed that is controlled by magnetic valves 44 and 45 _t which in turn are controlled by signals after that are provided by the controller and writing unit 46, which has been described in detail with reference to FIG sixteenth This unit is connected to a resistance thermometer 4y, a glass electrode 48, a calomel electrode 49 and a silver electrode 50. The emulsion obtained in the device 41 is introduced into the device 51, in which it is subjected to ripening at a temperature T which is not necessarily the same as T .. An additional precipitation of silver halide can now take place on the nuclei already formed which results in crystal growth. The supply port 52 with control valve 53 is used for supplying additional silver salts, halide and / or silver halide solvents or gelatin such as pthaloyl gelatin.

The emulsion is possibly partly or wholly returned through the line 54, which is provided with a regulating pump 55 .

At the end of the physical ripening the gelatin coagulated and coincides with the silver halide in the mixing device 5 ^> out. For this purpose and depending on the coagulation or flocculation method used, inlet 57, which is connected to a

ι control valve 58 is provided, introduced a precipitant. It can be there So an aqueous solution of ammonium sulfate, organic sulfonic acids, e.g. polystyrene sulfonic acid, or just a pH-lowering compound

GV.461 109852/1927

can be used if acylated gelatin was added to the emulaon in the previous stage. In the coagulation stage, acid is introduced through inlet 57 to lower the pH to about h , whereupon coagulation of the gelatin takes place. The coagulate, which is preferably in the form of fine, solid lumps, is poured onto an endless belt 59 of sieve-like design . A fine jet of wash water is then directed at the lumps, for example from a conduit 60 running the full length of the belt 59. In a particular embodiment, a second and third wash can take place in a refrigerated mixer of the type described in this invention , but which has a sieve-like perforated chamber wall, whereby the washing liquids are removed.

At the end of the washing stage, the lumps become one in the funnel Mixing device 61 out, and with vigorous stirring at a suitable temperature and a suitable pH, the coagulate is dispersed in it again. The pH-controlling compounds and the water, both at one suitable for re-dispersion Temperature are supplied through the inlet port 62, the is provided with a control valve 63 is introduced.

The redispersed silver halide crystals, which are their final Grain size distribution and their impurities and the excess halogen ions are freed, are now suitable to be mixed with chemical sensitizers in a mixer 65 to become which'through the outlet 6 * f with the mixing device 61 is connected.

The chemical sensitization essentially consists of the addition of Emulsion of chemical compounds that increase their sensitivity to light * The sensitization is with a special thermal Treatment associated, usually after the addition of the sensitizers is made. This treatment at a higher level

inqR *;? / iq? 7 original inspected

Temperature, for example at 4θ-75 ° _5, can last from icy minutes to a few hours until the desired sensitivity and the highest permissible haze value are achieved «

The chemical sensitizers are in a controlled manner through the line 66, which is connected to a valve 6? is provided, added. The outlet opening 68 of the mixing device 65 is connected directly or via a storage container connected in between to a spiral 69 which is arranged in a large thermostatic vessel 70 which is provided with the required temperature control unit and the agitator 72 . The flow rate of the emulsion through the spiral determines the digestion time.

There are three standing for the digestion process, depending on the purpose it has achieved Types of chemical sensitization available:

1) sulfur sensitization,

2) Heduction sensitization, and

3) Precious metal sensitization

At the end of the chemical sensitization, the aids necessary to obtain the photographic emulsion in its final, ready-to-cast form are introduced into the mixing device 7 through line 75, which is equipped with a valve 6 , and there with the silver halide emulsion, which passes through line 73 is introduced, mixed "The ready-to-pour emulsion is drained into the pouring trough 77, in which the emulsion level is carefully controlled." and passed around a roller 80 which is arranged so that the carrier 78 comes into contact with the surface of the emulsion Si which is maintained at a precisely controlled temperature.

To the transport of the photographic emulsion from and to the verssMedenen To facilitate mixing devices, the latter are preferably added together with the SCaslsad® aageordaet © the ia a tower of a 'stillstionsturm' is analogous, so «let the force of the force der Esralsiön τοη © iaer forriefetffiag ia iia i

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~ ²⁵ ~ 21U223

When working in light-tight containers, only the washing and casting rooms with the well-known darkroom safety lighting to be provided so that the greater part of the processing can be carried out in normally lit work rooms.

The method according to the invention can not only be used for the production of silver halide emulsions, but can also be used in the production of all types of suspensions and emulsions in which all types of physical or chemical reactions are used, the substances in the form of particles or droplets in a liquid phase. For example, the method can be used for the production of all kinds of poorly water-soluble salts or complexes, e.g. nickel dimethylglyoxime, barium sulfate, lead chromate, zinc chromate, cadmium sulfide, zinc sulfide and other fluorescent materials that are suitable, for example, for fluorescent screens, metal oxides and hydroxides, e.g. mercury (in turbulent flow conditions) II) oxide, lead (II) hydroxide, iron (III) hydroxide and chromium (III) hydroxide and metal particles, for example gold _→ mercury and silver dispersions, which are obtained by reduction. The method can also be used for the salting out of organic and inorganic compounds and for the production of polymer latexes, as well as all types of colloidal dispersions that are based on colloidal or polymer solutions.

Ate further examples of the use of the inventive Method may be mentioned: the preparation of emulsions with very small droplets by creating an emulsion with larger droplets is introduced into the mixing passage, in which the turbulence predominates, so that the droplets by the action of the thrust forces, which are caused by the whole mass of liquid in the passage are broken up. The inventive method for Formation of emulsions by mixing the materials, which is a continuous and forming a disperse phase is of particular importance in the emulsification of color couplers used in photographic materials must be used, e.g. in the production of emulsions from a non-volatile organic liquid

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in an aqueous gelatin solution, this liquid contains a dissolved color coupler. Achieving a narrow size distribution of the oil droplets is important for the production a uniform reaction of the color coupler at all points of the photographic material and for the production of images with low graininess. It has also been found that such Emulsions produced according to the invention are not opalescent, but rather form layers which, when dry, are completely transparent are. Moreover, the layers are much more resistant to damage from folding than the layers made with the usual emulsions are made. This is due to the very good elasticity of the layers.

Another specific example of the use of this invention is the production of barium sulfate dispersions in a protective colloid for the formation of barite cover layers on paper and other types of substrates.

The following examples illustrate the invention.

example 1

The following three solutions are made separately:

(A) an aqueous ammoniacal silver nitrate solution per liter Contains 0.857 moles of silver nitrate and 1.71 ^ moles of ammonium hydroxide,

(B) an aqueous halide solution containing 3 moles of potassium halide per liter (KBr / KCl / KJ- IOO / IO / I parts by weight),

(C) an aqueous acetic acid solution containing 3.5 moles of acetic acid per liter contains,

(D) an aqueous 0.5% strength by weight gelatin solution.

With these solutions, the precipitation (emulsification) of the light-sensitive Silver halide made in a mixing vessel that contains an introduction system according to FIG. 15 and a housing and an eotor as shown schematically in FIG.

The height h ,. (Figure 8) of the rotor part in the conical chamber was 122 mm. The height h_ of the kotor part in the funnel was 65 mm. The diameter of the rotor was 0. 5 mm and the diameter of ^ 0 ₂ 5 mm. The angles α and β were both 10 °. The margin (c) was 1.5 ram.

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In the rotor there was a helical groove with a right angle Incised cross-section.

The width of the groove between the peaks of the thread was 7 mm, the width of the peaks 3 mm and the depth of the groove 1.5 mm. The rotor and the light-tight housing were made of stainless steel. The angular speed of the rotor during the precipitation was 76O D / min.

Solutions (A), (B), (C) and (D) were introduced at the same time in the following proportions through the separate inlet openings 1 * f, 15 » 16 and 19 as indicated in Figure 15, introduced: Solution (A): 17 ^ ml per min.

Solution (B): 148 ml per min.

Solution (C): 82 ml per min.

Solution (D): 280 ml per min.

When working under these conditions, the contact time was of reagents in the thin film space approximately 2.5 sec.

The temperature was kept constant at ^ 9 ° during the precipitation. The pH and pAg values at the drain opening are expressed in mV measured were 8.15 and -35 mV, respectively.

The apparatus was operated under the working conditions given above for 16 min. kept in operation.

The mean diameter of the obtained silver halide grains was 11 ^ nm. This diameter was determined on the basis of the specific adsorption · a dye as described in Photographic Korrespondenz, Volume 101, No. 3 (1965), pp. 38-39 and by electron microscopic Measurement determined *

From the grain size distribution table of FIG. 18 it can be seen that this distribution is very narrow. The ordinate shows the increasing grain diameters expressed in nanometers (nm), while the number (N), which is expressed as the percentage of grains with a diameter smaller, has been entered on the abscissa

109852/1927

than the corresponding value on the abscissa »The diagram shows that 98 % of the grains have a size between 50 and 300 nm»

Example 2

This example relates to the production of photographic silver halide emulsions with a large grain size distribution A multi-stage treatment »Ee the following solutions were used produced in a first precipitation stage:

(A) A mixture of 1.5 parts by volume of ammoniacal silver nitrate, those per liter are 3 moles of silver nitrate and 6 moles of jtaflonium hydroxide contains, and 3.5 parts by volume of demineralized water;

(B) a homogeneous mixture of:

a 3 molar aqueous solution of potassium bromide 4000 ml

a 3 molar aqueous solution of sodium chloride 300 ml

a 3 molar aqueous solution of potassium iodide 100 ml

demineralized water 2700 ml

Inert gelatin, 300 g

enough aqueous ammonium hydroxide to maintain pH equal to 10.5 measured at ^ 0 °.

- First coating stage

Sb became a mixer 1 of the type described in Example 1 used, and the solutions (A) and (B) were through separate inlets in the ratio of 65 and 300 ml per Min. Introduced therein.

During the precipitation, the angular velocity of the eotor was 500 The temperature measured at the outlet was 62 °.

The pH and pAg values measured at the drain opening and expressed in mV were 10.8 and -16O mV, respectively. This first stage of precipitation took 3 minutes.

· = · Second stage of precipitation

Yes the same. Mixing device as in the first precipitation stage »Jeadet, the following solutions were separated by inlet openings ia dea the respective ratio © a introduced:

109 852/1927

- Liquid (A) as used in precipitation stage 1 in one Ratio of 65 rcl per min

- Liquid (B) as used in precipitation stage 1 in a ratio of 300 ml per min.

- the dispersion which comes from the mixer at the precipitation stage 1 was drained, at a ratio of 500 ml per min.

This second stage of precipitation took 2 minutes.

- Third stage of precipitation

The first stage of precipitation was repeated with the difference, however, that the dispersion obtained from the second precipitation stage was used together with the solutions (A) and (B) of the first stage The introduction speeds were as follows:

- Solution (A): 65 ml per min.

- Solution (B): 3OO ml per min.

Yield of the dispersion of the second precipitation stage: 500 ml per minute. The mean diameter of the silver halide grains obtained was measured with an electron microscope. It was 300 nm.

The results are shown in FIG. 19, from which it can be deduced that 98 % of the grains had a grain size between 10 and 1000 nm The abscissa is the number N (expressed as a percentage) of the grains with a diameter smaller than that which corresponds to the nm-Vfert.

Example ^

The following y, ier solutions were prepared separately:

(A) an aqueous solution containing 0.3 mol of silver nitrate per liter,

(B) an aqueous halide solution containing 0.3 mol of potassium bromide per liter,

(C) an aqueous acetic acid solution containing 3.5 moles of acetic acid per liter contains,

(D) an aqueous 1% strength by weight gelatin solution.

109852/1927

With these solutions the precipitation (emulsification) of the photosensitive Silver bromides carried out in a mixing vessel, which has an inlet stea of Figure 15 and a housing and a rotor as shown schematically in FIG.

The height h. (Figure 8) of the hotort part in the conical chamber was 122 mm. The height hp of the rotor part in the funnel was 65 mm. The diameter 0 of the rotor was 5 ^ mm and the diameter jZL 5 mm. The angles and β were both 10 °. The clearance (c) was 1.5 mm.

In the rotor there was a helical groove with a rectangular shape Incised cross-section. The width of the groove between the peaks of the thread was 7 mm, the width of the peaks 3 mm and the depth of the Groove 1.5 mm · The rotor and the light-tight housing were made of stainless steel Made of steel. The angular speed of the rotor during the precipitation was 900 D / min.

The solutions (A), (B), (C) and (D) were at the same time in the following proportions through the separate inlet openings lh. 15, 16 or 19, as indicated in FIG. 15, introduced: Solution (A): 193 ml per min.
Solution (B): 164 ml per min.
Solution (C): 58 ml per min
Solution (D): 700 ml per min.

Operating under these conditions, the silver ion concentration, measured potentiometrically at the mixer vent, was such that it coincided with a millivolt reading between +300 and + A-00 mV. The pH of the emulsion leaving the device was between 3 and 4. The contact time of the reagents in the headroom was approximately 2.5 seconds.

The temperature was kept constant at 35 ° during the precipitation.

The dispersion exiting the device was at such a rate with an aqueous potassium bromide solution mixed that in the mixed Composition a voltage of +50 mV measured potentiometrically became·

10 9 852/1927

The mean diameter of the silver halide grains obtained at the vent was 100 mn. The mean diameter of the grains was turbidimetric as described in Sei.Ind.Phot. (2) Volume 19, November 19 ** 8, pp. ^ 01- ^ 18 and by measurement with an electron microscope certainly.

When per mole of silver nitrate 300 mg of 1-phenyl-2-tetrazoline-5-thione with of the following tautomeric structure:

in solution (B) was used as a grain growth retarder »and if one Working there under the conditions described above, silver bromide grains with an average diameter of 20 mn received.

example k

The following four solutions were prepared separately:

(A) an aqueous solution containing 0.3 mol of silver nitrate per liter,

(B) an aqueous halide solution containing 0.3 mol of potassium bromide per liter contained

(C) a 20% aqueous solution of acetic acid,

(D) a 1% strength by weight aqueous gelatin solution.

The photosensitive silver bromide was precipitated with these solutions in a mixing vessel with a turbulent flow a feed system according to FIG. 15 as well as a housing and possessed a Botor according to the figure 1 ^.

The height h. (Figure 8) of the eotor part in the conical chamber was 122 mm. The height of the kotor part in the funnel was 65 mm. The diameter of 0. Botors was 5 mm and the diameter ^ #J_ 5 mm. The clearance (C) was 1.5 mm. The pitch of the thread on the rotor was 6 mm. The depth of the groove was 2 mm and the width of the groove between the thread crests was 6.5 mm.

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The rotor and the light-tight housing were made of stainless steel.

The angular velocity of the hotor during the precipitation was 85O rpm. Solutions (A), (B), (C) and (D) were made at the same time through the separate feed openings 1 ^, 15, 16 and 19 as in of Figure 15, introduced

The solution (C) was introduced at such a rate that a pH value of 3.5 was obtained at the outlet opening of the device in all of the experiments described below.

Solution (D) was used in all of the experiments described below generally supplied to a ratio of 600 ml per minute «

The following Table 1 gives data which of sixteen different ones Experiments originate and show the evolution of the silver halide grain size as a function of the pAg value measured at the discharge opening of the mixer with turbulent flow. The pAg values and the density values (D), which correspond to the turbidity of the dispersions, were measured at 750 nm 1.5 min after the Exiting the mixer measured by the emulsion. The measurement was carried out in the cells of a spectrophotometer "Spectronic 505" (Trademark of Bausch and Lomb Inc., Kochester, N.Y., U.S.A.) performed.

The turbidity density is directly proportional to the grain size of precipitated silver halide "

The silver nitrate solution (solution A) and the potassium bromide solution (solution B) were introduced in an equimolar ratio at a flow rate of 152 ml per min. The one in the precipitation reaction maintained temperature was 35 °

Table 1

Attempt no. ρAg value Density (D) 2 2.75
3.15 0.31
. 0.30

109852/1927

Γ; ~ " 3.65 0.34 4th 4.00 0.39 VJi 4.35 0.51 6th 4.70 0.47 7th 4.85 0.84 8th 5.60 0.46 9 5.85 0.43 10 10.00 0.50 11th 9.20 0.33 12th 8.50 0.31 13th 7.80 0.40 14th 7.40 0.44 15th 6.50 0.52 ¹ 16 6.30 0.52

The diagrams of Figures 22 and 23 were made in relation to the experiments 1 to 16 is obtained by plotting the turbidity density (D) against the Wavelength from 76Ο to 600 nm entered. Curves 1-9 of the figure 22 correspond to experiments 1-9 of the above table and curves 1-7 of FIG. 23 correspond to experiments 10-16 of this table.

It can be seen from these curves that in the region of low pAg values, i.e. from 2.75 to 6, the turbidity m. A «W. the middle Grain size is minimal at the pAg value at which the solubility of the silver halide is also minimal (pAg = 3.00).

In the area of the higher pAg values 10 to 6, the turbidity is minimal at pAg = 8.5 because of the excess of halide ions with respect to silver ions.

Example 5

The procedure was as in Example 4 with a pAg value of 7.9 (= 85 mV) and precipitation temperatures of 35 and 42 °, respectively.

In FIG. 24, curves 1 and 2 show the relationship between turbidity density (D) and wavelength (nm) in relation to silver bromide dispersions, which were made at 35 and 42 °, respectively.

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From these curves it can be seen that the grain size of the silver bromide grows proportionally to the precipitation temperature

Example 6 '

The following four solutions were made separately:

(A) an aqueous solution containing 0.3 mol of silver nitrate per liter,

(B) an aqueous halide dip containing 0.3 mol of potassium bromide per liter and contained 2 wt. # gelatin,

(C) a 20 # aqueous acetic acid solution,

(D) an aqueous 1% strength by weight gelatin solution

With these solutions the precipitation of light-sensitive silver bromide was carried out in a mixing vessel with turbulent flow as described in example ΐ ]

During the precipitation the angular velocity of the hotor was 85Ο RPM

Curves 1 and 2 of Figure 25 indicate the effect of the silver ions and halide ion concentration on the grain size of the silver halide there.

At the beginning of the precipitation these concentrations could easily pass through the supply of the solution (D) acting as a diluent can be controlled.

The working conditions for two experiments were chosen such that in a first attempt the silver nitrate and potassium bromide in the mixing vessel came into contact in concentrations of 0.05 mol / liter, while in a second experiment the concentrations at this contact were 0.075 mol / liter. These conditions became achieved 1 by adding the silver nitrate solution (A) and the potassium bromide solution (B) in equimolar amounts in a ratio of 152 ml per min. And the liquid (D) in a ratio of 6OO and 3OO ml per minute for experiments 1 and 2, respectively. During this process, the pH value is kept at 3.5 by means of solution (C). The temperature was maintained at 35 °.

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~ ³⁹ ~ 21H223

The emulsion samples obtained from the Miechgefäß were taken 1.5 minutes after the formation of the precipitate and their turbidity was measured as described in Example h.

Curve 1 in FIG. 25 represents the dependence of the turbidity density of the wavelength of the sample obtained in Experiment 1, with 0.05 mol of silver nitrate and 0.05 mol of potassium bromide per liter in the Precipitation stage were used

Curve 2 in FIG. 25 represents the dependence of the turbidity density of the wavelength for the sample obtained in Experiment 2, where 0.075 mol of silver nitrate and 0.075 mol of potassium bromide were used per liter in the precipitation stage

From the curves in FIG. 25 it can be deduced that with a Increase in the concentration of the starting materials (silver and halide ions) the grain size of the silver halide increases, and that by the use of a low-concentration solution, i.e. a solution which contains about 0.05 per liter of each reagent, very fine grains can be obtained under the conditions described · The average grain size of the silver halide grains obtained in experiments ΐ and 2 were 11 or 26 mn

Example 7

The following six solutions were made separately:

(A) an aqueous solution containing 0.3 mol of silver nitrate per liter,

(B) an aqueous solution containing 0.3 mol of potassium bromide per liter as well Contained 2% by weight of gelatine,

(C) a 20% aqueous acetic acid solution,

(D) an aqueous 1% strength by weight gelatin solution,

(E) an aqueous 1 N sodium hydroxide solution as the pH-controlling solution,

(F) as the solution controlling the pAg value, an aqueous solution of 0.03 mol Silver nitrate per liter.

With these solutions the precipitation of the photosensitive silver bromide was carried out in a mixing vessel with turbulent flow such as

109852/1927

21H223.

written in example k made. During the precipitation, the angular speed of the rotor 85O r / min "was Curves 1 and 2 of Figure 26 are an indication of the pH effect on the silver '■ grain size at einem'konstanten pAg of 2.75"

In a first experiment, represented by curve 1, the precipitation reaction was carried out at a pH * value of 3> 5, while in a second experiment, represented by curve 2, the precipitation took place at a pH of 3 .

Samples of the emulsions produced in this mixer were taken 1.5 minutes after the precipitation and their turbidity was measured as described in example h

Curve 1 in FIG. 26 represents the dependence of the turbidity density (D) on the wavelength (nm) of the product of the first experiment obtained by working at a pH equal to 3j5 proceeded.

Curve 2 in FIG. 26 represents the dependence of the turbidity density (D) represents the wavelength of the product obtained after the second test, obtained at pH 5 became·

From the curves in FIG. 26 it can be deduced that the grain size of silver halide grows with increasing pH. The mean grain size was in the first and second trials 11 or 36 nm

Example 8

The following four solutions were made:

(A) an aqueous solution containing 0.3 mol of silver nitrate per liter,

(B) an aqueous Halogenidlosung containing per liter of 0.3 mol of potassium bromide and 2 wt.% Of gelatin,

(G) a 20 # aqueous acetic acid solution, (D) an aqueous 1% strength by weight gelatin solution.

With these solutions, the precipitation reaction of the light-sensitive

1 Ö 9 8 5 2/19 2 7

21H223

silver bromide carried out in a mixing vessel with turbulent Flow with a feed system according to FIG. 15 and with a housing and a rotor as shown in FIG.

The height h. (Figure 8) of the eotor part in the conical chamber was 122 mm. The height of the eotor part in the funnel was 65 mm. The diameter 0 ^ of the rotor was 5 ^ mm and the diameter jZL was 5 mm. The clearance (C) was 1.5 mm

The door and the light-tight housing were made of stainless steel. The angular speed of the rotor during the precipitation was 800 rpm.

The solutions (A), (B), (C) and (D) were introduced at the same time through the separate inlet openings I ² *, 15 »16 and 19, respectively, as shown in the figure.

Solution (C) was added in such a ratio that a pH of 3 ₅ 5 was measured at the drain opening of the device in all of the experiments described below.

The solution (D) was in a ratio of 6OO el per min. In all added to the experiments described below. The millivolt reading at the vent opening was * f20 mV. Immediately after As the silver bromide solution exited the device, enough aqueous potassium bromide solution was added to bring the millivolt value to 50.

In experiment 1, which is the reference experiment, during the precipitation no grain growth retarder added.

In experiment 2, 1 ml of 20 # aqueous was used as a grain growth retarder Solution of poly-N-vinylpyrrolidone per 100 ml of emulsion that left the device, added.

In FIG. 27, curves 1, 3 and h represent the "dependence of the turbidity density on the wavelength of a sample of the product from experiment 1 which, 1.5 minutes, 10 minutes and 20 minutes after it The mixing vessel was removed · Curve 2 shows the dependence of the turbidity density on the wavelength of a sample

βνΛ6ι 109852/1927

of the product from Experiment 2, 1.5 min. after the mixer left The turbidity would be achieved with a "Spectronic 505"

Spectrophotometer, described in Example k, measured. ί

Example 9

The following four solutions were made separately:

(A) an aqueous solution containing 0.3 mol of silver nitrate per liter,

(B) an aqueous solution containing 0.3 mol of potassium bromide per liter as well 2 wt. ^ Gelatin contained,

(C) an aqueous acetic acid solution,

(D) an aqueous 1% strength by weight gelatin solution.

The precipitation reaction of the photosensitive silver bromide was carried out with these solutions in a mixer with turbulent flow as described in Example h. During the precipitation reaction, the angular speed of the rotor was 900 rpm.

The solutions (A), (B), (C) and (D) were added at the same time through the separate inlet openings 1 ² *, 15, 16 and 19, as shown in FIG. 15, in the proportions of 190, 16O, 70 or 700 ml per min.

A number of experiments were carried out in which immediately after the silver bromide emulsion left the mixing vessel, 0.5 millimoles a grain growth retarder was added. The dispersion was measured to a millivolt reading with an aqueous potassium bromide solution of +50 mV (silver electrode saturated calomel electrode).

Emulsion samples from the various experiments were then treated with an aqueous 20% strength by weight ammonium sulfate solution under the same conditions treated, and the precipitated gelatin coated silver halide grains Washed with 5 liters of demineralized water containing 0.25 millimoles of a grain growth retarder "as used above.

The whole process of precipitation and washing of the emulsion grains lasted 1.5 hour. After each specimen had been stored for 2 hours at ^ 0 °, Samples were taken and photographs of the silver bromide grains were taken in an electron microscope (50,000 times "" "magnification).

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21H223,

In Table II below are the grain growth retarders used and the average silver bromide grain sizes achieved in the various tests.

Table II

Attempt no »Grain growth retarders N
/ \
S = CN
I Il
HN N 0 H Medium grain
size 1 - I Il I
H ₂ N- ^ JJ NH 60 nm 2 ό kO nm 3 HN-N 30 nm k 22 nm 5 18 nm

In FIG. 28, curve 1 shows the dependence of the turbidity density of the wavelength of a sample produced under the conditions of Experiment 1, 1.5 minutes after leaving

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21U223

was removed from the mixing vessel. The curve 2 represents the dependence of the density of the Turbiditat: represents wavelength of a pattern produced the w ü under the same conditions as was in attempting k estnoBsaen, 1.5 min "after leaving the mixing vessel"

Example 10

The following liquids (A) and (B) were prepared in view of their mixing in the mixer as shown in Figure 8:

(A) a 10% strength by weight aqueous gelatin solution,

(B) dibutyl phthalate.

The height h _{1 of} the hotort part in the cone-shaped kajamer was 122 mm. The height hp of the rotor part in the funnel was 6 ^ 5 mm. The diameter ^ _{1 of} the rotor was 5 ** mm and the diameter 0 ~ 5 mm. The angles a and β each amounted to 10 °. The clearance (c) during the process was 0.87 mm. The rotor was made of stainless steel and had a smooth surface. Its speed was 1000 rpm.

The liquids (A) and (B) were introduced into the clearance on the upper part through separate inlet openings, the liquid (A) in a ratio of 700 ml in 3 minutes x 55 seconds, the liquid (B) in a ratio of 8, 4- ml in the same period of time

The temperature of the liquids in the mixing zone was kO °. The liquid obtained from the discharge port was once again introduced into the mixer through one of the inlet ports.

They sublime emulsion was coated in a ratio of IZ, 5 g of gelatin per m2 on a subbed cellulose triacetate support. Tests to measure the brittleness showed that the emulsion layer showed a much better resistance to damage by folding than layers which did not contain any dibutylgate halate droplets.

The gelatin layer with the oil droplets was in a dry state completely transparent. Equally good results were obtained with dimethyl phthalate. Even better elasticity was obtained in that

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" ^k3 ~ 21U223

higher levels of dibutyl phthalate or dimethyl phthalate were used and these were introduced into the liquids in proportions of 11.2 ml and 14 ml, respectively, per 3 min. 55 sec.

This example shows how, in an analogous way, an emulsion - before organic, hydrophobic "liquid droplets containing a color coupler in a dissolved state in a colloidal hydrophilic binder can be prepared in accordance with the present invention.

Example 11

Barium sulfate was prepared using the apparatus like that of Example 3, but which has a Botor without a helical Had circumferential groove.

There were two liquids (P) and (Q) separately in the slack inserted between the rotor and the housing?

(P) an aqueous 1 molar sulfuric acid solution, (Q) an aqueous 1 molar barium chloride solution.

The feeding ratio of the liquids (P) and (Q) was 100 ml in 2k sec. And 100 ml in 25 sec, respectively. The liquids were introduced tangentially to the rotor surface in the clearance and in the direction of rotation of the rotor. The clearance was 1.7 mm wide, the temperature was 20 ° and the rotor speed was 815 rpm.

To compare the difference in grain size between barium sulfate, from the same solution in a batch process (i.e. in a vessel equipped with a helical agitator is) and the barium sulfate, which was produced according to this example, their deposition rates were measured.

A sample produced on a batch-wise basis, exhibited a 15 minute settling time in a sample tube. A sample made according to the continuous process of this example required the same degree of deposition (1 cm clear liquid at the top of the column) a 95 minute deposition time.

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- hey -

21H223

Example 12

A dispersion of ethyl cellulose in an ethanol-water mixture was made with the same mixer as that used in Example 10, manufactured"

Two starting liquids, namely water and a 5% by weight Ethanol solution of ethyl cellulose N7 (trade name of The Hercules Powder Company Inc, Wilmington, Del ·, U.S.A. for a Ethyl cellulose, which is insoluble in a water-ethanol mixture (1/1 in volume)) were separately in the clearance between the rotor and Housing introduced. The rotor speed was 930 rpm, a backlash 0,44 mm and temperature of liquids 20 °.

The water and ethyl cellulose solution were in proportions of 10 * f or 1 ^ ml per minute introduced.

A batch process in which with a high-speed agitator was worked, and using the same liquids in the same volume ratio, resulted in a much coarser grain Dispersion than that obtained with the continuously working turbulent flow mixer according to this example.

Example 13

The following four solutions were made separately:

(A) an aqueous solution containing 0.3 mol of silver nitrate per liter, and diluted with 5 times the volume of distilled water.

(B) 500 ml of an aqueous solution containing 0.3 mol of potassium bromide, 16 g Gelatin, 2 ^ 84 ml of distilled water, 1000 ml of ethanol and Contained 10 g of the grain growth retardant having the following formula:

^N C = S

(C) a dilute aqueous acetic acid solution,

(D) an aqueous solution containing 3200 ml of water, 800 g of gelatin and 5 g of the above-mentioned grain growth retarder.

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- νη -

21U223

Starting from these solutions, the precipitate of the photosensitive silver bromide in a mixer with turbulent Flow as shown schematically in Figure 1, but carried out in which the solutions (A) and (D) in the center of the conical Eotorteils in the funnel and the solutions B and C were added by spraying on the inner wall of the funnel.

The dimensions of the mixer were as follows: h * = 91 mm
h_ = ^ 5 mm
0 _Λ = kZ mm 0 ~ - 6 mm

The clearance (C) was 1.2 mm and the angular speed of the rotor during the introduction of these aqueous solutions II was 50 rpm.

Solutions (A), (B), (C) and (D) were added at a rate of 200, 205, 150 and 190 ml per minute, respectively.

The pH was maintained at 3.2 and the millivolt reading at the drain opening, which is a measure of the pAg, was + kkO mV when operating at a precipitation temperature of 38 ^ 3. After the precipitation, the millivolt reading was adjusted to 70 mV by mixing the precipitate with aqueous potassium bromide solution.

Samples taken from this treated precipitate were obtained a larger part of silver halide grains with a grain size of 5 nm «

Example 14

The following two solutions were prepared separately:

(A) a solution of 150 g of polymethyl methacrylate in 750 ml of ethyl acetate,

(B) a solution of 300 g of gelatin, dissolved in 2100 ml of water, which contained Zk ml of a 20% strength by weight aqueous solution of the dispersant MEBSOLAT (trade name of Bayer AG, Leverkusen, for a sulfonated paraffin).

These X solutions A and B were at the same time in the ring-shaped passage of a mixing vessel with a in the figure k schematically

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21U223

shown housing and Hotor introduced.

The high h. (See Figure 8) of the rotor part in the conical chamber was 122 mm. The height of the hotor parts in the funnel was 65 mm. The diameter 0 * of the rotor was 5 ** mm and the diameter 0.5 mm. Both angles α and β amounted to 10 °. The clearance (C) was 1.7 mm.

The Hotor had a smooth surface and was like the light-tight housing made of stainless steel.

The angular speed of the rotor during the mixing process was 1030 rpm.

Solutions (A) and (B) were in the proportions of 70 and 92 ml added per minute.

When working under these circumstances, the contact time of the reagents in the range was approximately I φ $? \ 2 seconds. The temperature was kept at hk ° during the dispersion process. The mean diameter of the dispersed polymethyl methacrylate particles was determined by microscopic measurement. It was 5000 nnu

The size distribution of the particles obtained in this process was much more homogeneous than in a batch dispersing technique could be obtained. moreover it is with the present mixing process with continuous flow in the form of a thin film possible, much more concentrated polymer solutions as well as less To use dispersants and gelatin as protective colloid.

Example 15

Example 13 was repeated with the difference, however, that an equal amount of the grain growth retarder was used according to one of the following Structural formulas used:

S0_Na

\ ³ A

Cl-Lx U NH »Cl-

^{GV </ f61} 109852/1927

HO S-

Vs

NH

HO S- k>

C-SH

.N

Silver halide grains produced in the presence of such a retarder had an average grain size of 5 nm.

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Claims (26)

21U223 claims 1. Method for mixing liquids containing ingredients, which result in a disperse phase by mixing, characterized in that the liquids to be mixed be introduced in a continuous manner into a passage, over the entire cross section of which the supplied liquids in continuous flow are guided away from the inlet point or points, and through this passage flowing liquid mass is subjected to forces which cause turbulence in it. 2. The method according to claim 1, characterized in that the ingredients react chemically and result in a product that forms a solid disperse phase 3 · The method according to claim 2, characterized in that the Ingredients are a dissolved silver salt and a dissolved halide, which are supplied from separate aqueous liquids. 4. The method according to any one of claims 1 to 3, characterized in that that the liquids entering the passage in any For a moment, it should not be mixed with the material that had already been subjected to shear forces in the passage. 5 «Method according to claims 2 to ^, characterized in that the various liquids contain ingredients for a precipitating chemical reaction and are continuous and are introduced separately into the mixing passage, the cross-sectional dimensions and degree of turbulence thereof being such that the quantities of reagent entering the passage at any given moment are almost entirely for nucleation and not all at once noticeable extent. are consumed to produce grain growth. 6. The method according to any one of the preceding claims, characterized in, that the passage has cross-sectional dimensions, which the flow of a liquid film with a thickness allow less than 5 mm ^ανΛ61 109852/1927 . - ⁵¹ - 21U223 7 · Method according to any one of the preceding claims, characterized in characterized in that the mass of liquid in the passage at each point has an average velocity component has in the direction in which the liquid is advancing along the passage and all or almost all of its Parts in the passage are subjected to shear forces, which results in a turbulent flow. 8. The method according to claim 7, characterized in that a turbulent flow is achieved by applying pressure to the liquid in the flow direction in this passage, which is sufficient to be well above the Reynolds number to maintain the critical value at which conditions of turbulent flow occur " 9 «Method according to claim 7, characterized in that a turbulent flow is created by placing a wall or walls of the passage at a sufficient speed or at sufficient speeds to avoid frictional forces, which are generated by the contact of the liquid mass with these moving walls, causing the turbulent flow 10. The method according to claim 9 «characterized in that the Passage is a layered space that is delimited by walls which are continuously rotated around an axis in order to produce the frictional forces. 11 «The method according to claim 9, characterized in that the layered space is determined by two discs, one of which at least one is rotated with respect to the other at a speed that is equal to that in the liquids entering the central part the disk or disks are introduced and drained at their periphery, causing a turbulent flow. 12.Verfahren according to claim 9, characterized in that the layer-shaped space is ring-shaped and'by opposite Surfaces of revolution is determined, with the liquid in the Passage entirely or for the most part in turbulent. flow GV.lf6i 109852/1927 21U223 is held by frictional forces caused by the rotation these surfaces caused around their common axis of rotation will" 13 «The method according to claim 12, characterized in that the Liquids are mixed in a device that has an inner body contains, which is rotatable within a radially symmetrical space which is delimited by an enveloping housing, thus defining an annular tree through which liquid material can flow by placing such material continuously feeds into the annular space at one end and continuously in a matching ratio from that the other end of this space continuously drains while the inner body rotates at a sufficient speed is held to be the Reynoldaeche number that leads to the fluid flow along such a space it is important to keep above the critical value under the conditions of a turbulent one Flow occur 14. The method according to claim 13j, characterized in that the The inner profile of the housing and the outer profile of the inner body tapers towards the drain opening, so that the annular Space decreases towards the drain opening of the room. 15 · The method according to claim 1 * f, characterized in that the Liquids are mixed in a device that has a central inner body (rotor) and an outer body (housing) which envelops the dumbbell surface of the rotor, and in which the housing and the rotor are arranged coaxially, and a play space or a layered space in dpr form form an annular passage "which has a cross-section that continuously decreases perpendicular to the axis of rotation, the layered space serving at its larger cross section as an inlet opening for the mixing zone, which between the rotor shell and the surrounding surface of the housing is formed, and with its smaller cross-section than the discharge opening serves for the mixing zone, and the opposite walls ι which 1 09852/1927 21U223 represent the layered space, non-perforated, smooth or are helically grooved, or have a roughness and / or point-like protuberances which produce a Promote turbulence in a liquid which is forced to flow through this clearance, whereby the rotor and / or the Housing are provided with a drive for his or her rotational movement about this axis. 16. The method according to any one of claims 3 to 15, characterized in, that one of the liquids supplied in the passage contains a protective colloid dissolved in water. 17. The method according to claim 16, characterized in that the protective colloid is gelatin. 18. The method according to any one of claims 3 to 17, characterized in, that the formation of the silver halide grains in the passage takes place in the presence of a grain growth retarder. 19. Method according to one of Claims 3 to 18, characterized in that that the formation of the silver halide grains takes place in a reaction medium in which the silver ion excess over the halide ions or vice versa is such that the pAg value in the reaction mixture is between 2.5 and 3.5 or between 7.5 and 8.5 lies. 20. The method according to any one of claims 3 to 19, characterized in that that the formation of the silver halide grains takes place under such mixing conditions that silver halide grains with an average grain size of less than 0.05 microns. 21. The method according to claim 1, characterized in that one of the Liquids introduced into the passage contain silver halide grains, onto which additional silver halide is present in that passage is felled. 109852/1927 22. The method according to claim 1, characterized in that the Silver halide grains which are coated with a protective colloid, be precipitated in the passage by means of a precipitant which is introduced into the passage in a liquid. 23 · The method according to claim 1, characterized in that with A protective colloid coated and precipitated silver halide grains are redispersed in this passage in an aqueous Liquid that is essentially free of a precipitant for these grains. 2k. Process according to Claim 1, characterized in that silver halide grains are treated in the passage with at least one substance * which influences their sensitivity to light. 25 · Method according to one of the preceding claims, characterized in, that the mixing process of the type described in claim 1 is carried out in devices that are in cascade internally connected so that gravity does the transport of the liquid mass from one device after the other. 26. The method according to claim 1, characterized in that water-immiscible organic polymer solutions in an aqueous medium by the simultaneous introduction of this solution and an aqueous medium Liquid to be dispersed in this passage in it 27. The method according to claim 26, characterized in that the aqueous medium contains gelatin. ^{GV </ f61} 109852/1927