JP2013144834A - Method of manufacturing minute particle dispersion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a minute particle dispersion, capable of efficiently dispersing minute particles without giving damages such as deformation and internal lattice distortion in the minute particle.SOLUTION: In the manufacturing of the minute particle dispersion, a treatment object liquid containing particles 42 in an aggregation state in the liquid 33b is collided with a collision surface 73b to disperse the particles 42 in a liquid 33b. At that time, the viscosity of the liquid 33b is adjusted to be equal to or higher than lower limit reference viscosity set according to the kind of the particles 42 and a parameter which stipulates physical force exerted to fine droplets 33a by a gas flow, so that the ratio of the collision of the particles 42 with the collision surface 73b becomes equal to or lower than a prescribed ratio and so that the deformation of an outer shape and the internal lattice distortion caused in the particles 42 due to the collision with the collision surface 73b become equal to or lower than a desired degree. Thus, excess impacts due to the direct collision of the particles 42 in the liquid 33b with the collision surface 73b are suppressed.

Description

  The present invention relates to a method for producing a fine particle dispersion in which a fine particle dispersion in which fine particles are dispersed in a liquid by treating a liquid to be treated containing fine particles in an aggregated state.

  In recent years, the importance of fine particles as materials used in various technical fields such as battery electrode materials, dielectric materials for electronic parts, fine metal particles for fine wiring, organic pigments for ink jets, catalysts, and pharmaceuticals has increased. Accordingly, new technology development relating to the production and handling of fine particles has been attempted (for example, see Patent Documents 1 and 2). In the prior art disclosed in Patent Document 1, a droplet containing solid particles is accelerated by a supersonic air flow and collided with a collision portion at high speed, whereby the solid particles are refined by a shock wave generated by the collision. The prior art disclosed in Patent Document 2 discloses a technique in which metal particles that are easily plastically deformed are atomized and dispersed by a high-pressure jet mill.

Japanese Patent No. 4444742 JP 2011-20081

  By the way, depending on the material type of the fine particles, damage such as deformation and lattice distortion inside the particles is likely to occur, and in applications where such damage is not allowed, damage occurs as much as possible in the process of manufacturing and dispersing fine particles. A processing method that does not exist is required. However, in the related art including the above-described patent document examples, the necessary processing cannot be performed without causing damage.

  For example, in the example shown in Patent Document 2, metal fine particles that are easily plastically deformed are atomized by compounding with ceramics or the like, and an efficient dispersion process with metal fine particles alone cannot be realized. In order to suppress the damage, the crushing driving force for dispersion is set low, the processing time is lengthened to obtain a desired processing quality, and the efficiency of the dispersion processing is hindered. Thus, in the prior art, there is a problem that it is difficult to efficiently disperse the fine particles without damaging the material that is easily damaged.

  Accordingly, an object of the present invention is to provide a method for producing a fine particle dispersion capable of efficiently dispersing fine particles without causing damage such as deformation and internal lattice distortion.

  The method for producing a fine particle dispersion according to the present invention includes a fine particle dispersion for producing a fine particle dispersion in which the fine particles are dispersed in the liquid by causing a liquid to be treated containing fine particles in an aggregated state to collide with a collision portion. A method for producing a body, wherein a viscosity adjusting step for adjusting a viscosity of a liquid in the liquid to be processed to be equal to or higher than a preset lower limit reference viscosity, a liquid supplying step for supplying the liquid to be processed into a gas flow, and A droplet accelerating step for accelerating and accelerating the supplied processing target liquid into a micro droplet by a gas flow, a droplet collision step for causing the accelerated micro droplet to collide with the collision portion, and the micro liquid by the collision A particle dispersion step of dispersing the agglomerated fine particles by a shock wave excited in the droplet, and in the viscosity adjustment step, the fine particles collide with the collision portion in the droplet collision step. The lower limit is set so that the ratio is not more than a predetermined ratio, and the deformation of the outer shape and the internal lattice distortion generated in these fine particles due to the collision with the collision portion in the particle dispersion step are not more than a desired degree. The reference viscosity is set according to the parameters defining the kind of the fine particles and the physical force that the gas flow exerts on the fine droplets.

  According to the present invention, in the manufacture of a fine particle dispersion in which fine particles are dispersed in a liquid by colliding the liquid to be treated containing the fine particles in an aggregated state in the liquid with the collision portion, the ratio of the fine particles colliding with the collision portion is The type of fine particles and the gas flow are small liquids so that the deformation of the outer shape and the internal lattice distortion generated in the fine particles due to the collision with the collision portion are not more than a desired degree. By adjusting the viscosity of the liquid above the lower reference viscosity set according to the parameters that define the physical force acting on the droplets, the impact caused by the fine particles in the liquid directly colliding with the collision part is suppressed, and the fine particles Thus, a fine particle dispersion can be efficiently produced without causing damage such as deformation and internal lattice distortion.

The block diagram which shows the structure of the manufacturing apparatus of the fine particle dispersion of one embodiment of this invention The perspective view of the manufacturing apparatus of the fine particle dispersion of one embodiment of this invention Sectional drawing of the injection chamber used for the manufacturing apparatus of the fine particle dispersion of one embodiment of this invention Sectional drawing of the jet nozzle (Laval nozzle) used for the manufacturing apparatus of the fine particle dispersion of one embodiment of this invention Sectional drawing of the jet nozzle (2 fluid nozzle) used for the manufacturing apparatus of the fine particle dispersion of one embodiment of this invention Sectional drawing of the jet nozzle (2 fluid nozzle) used for the manufacturing apparatus of the fine particle dispersion of one embodiment of this invention Piping system diagram in manufacturing apparatus of fine particle dispersion according to one embodiment of the present invention Process explanatory drawing which shows the transition of the process target liquid in the manufacturing method of the fine particle dispersion of one embodiment of this invention Process explanatory drawing of the manufacturing method of the particulate dispersion of one embodiment of the present invention Explanatory drawing of the disintegration / dispersion mechanism by the collision of the micro droplet in the manufacturing method of the fine particle dispersion of one embodiment of the present invention FIG. 4 is an enlarged view of fine particles and a graph showing the particle size distribution showing the result of fine particle dispersion in the method for producing a fine particle dispersion according to one embodiment of the present invention The graph which shows the relationship between the fine particle dispersion | distribution result in the manufacturing method of the fine particle dispersion of one embodiment of this invention, the viscosity of a liquid, and an injection pressure The graph which shows the X-ray-diffraction result which made object the microparticles | fine-particles in the manufacturing method of the fine particle dispersion of one embodiment of this invention

  Next, embodiments of the present invention will be described with reference to the drawings. First, with reference to FIG. 1, the whole structure of the manufacturing apparatus of a fine particle dispersion is demonstrated. The fine particle dispersion manufacturing apparatus 1 accelerates a liquid to be treated in which fine particles in an agglomerated state are contained in a liquid by a gas flow to form high-speed micro droplets, and causes the micro droplets to collide with a collision portion. Has a function of producing a fine particle dispersion dispersed in a liquid.

  In the present embodiment, an example is shown in which fine particles used in various technical fields are intended to have characteristics that easily cause damage such as deformation and internal distortion in the dispersion process. For example, metal particles made of ductile metals such as copper and silver used for conductive paste and fine wiring, lithium battery electrode materials, dielectric materials for electronic parts, hydrogen storage materials, ferromagnetic materials, etc. Damage to the outer surface is allowed, such as fine particles having properties that deteriorate when damaged, and so-called core-shell composite materials in which the surface of the core particles is coated with functional particles of a different type from the core The fine particles that are not used are the targets of the method for producing the fine particle dispersion shown in the present embodiment.

  In FIG. 1, an apparatus 1 for producing a fine particle dispersion includes a processing liquid storage unit 2 that stores a processing target liquid (hereinafter abbreviated as a processing liquid) containing aggregated fine particles to be processed in a liquid. The liquid and fine particles adjusted to a predetermined viscosity by the viscosity adjusting unit 3 are supplied to the processing liquid storage unit 2. In this embodiment, as will be described later, by appropriately adjusting the viscosity of the liquid containing the fine particles to be treated, damage such as deformation and lattice distortion inside the fine particles after the dispersion treatment is suppressed as much as possible. Like to do.

  The processing liquid stored in the processing liquid storage unit 2 is supplied to a jet nozzle 7 attached to the upper end of the injection chamber 6. The processing liquid is microdropletized by the gas flow generated by supplying air from the air supply source 5 to the jet nozzle 7 and accelerated at a high speed, and the collision unit 73 (FIG. 3) disposed in the injection chamber 6. C). As a result, the fine particles in the aggregated state are dispersed to form a fine particle dispersion, which is recovered in the treatment liquid recovery tank 9. An exhaust unit 8 is attached to the injection chamber 6 and collects mist-like exhaust generated in the injection chamber 6.

  Next, the configuration of the dispersion processing unit 4 used in the fine particle dispersion manufacturing apparatus 1 according to the present embodiment will be described with reference to FIGS. In FIG. 2, the dispersion processing unit 4 includes an injection chamber 6 and an exhaust unit 8. The injection chamber 6 is a vertical substantially cylindrical processing container that is divided into an upper part 61, an intermediate part 62, and a lower part 63. The upper part 61, the intermediate part 62, and the intermediate part 62 and the lower part 63 are each an annular joint. It is connected via 69a and 69b. As shown in FIG. 3, a nozzle holder 68 is coupled to a nozzle mounting portion 61a provided by narrowing the top of the upper portion 61 via an annular joint 69c, and the nozzle holder 68 constitutes droplet accelerating means. A jet nozzle 7 is mounted from above. With such a configuration, the upper portion 61, the intermediate portion 62, and the lower portion 63 can be easily disassembled as needed for internal component replacement, and the jet nozzle 7 can be easily attached and detached. ing,

  The jet nozzle 7 is provided with an air supply pipe 70 and a processing liquid supply pipe 71, and driving air for generating a gas flow in the jet nozzle 7 by the air supply pipe 70 and the processing liquid supply pipe 71 and A treatment liquid containing fine particles to be dispersed is supplied. A flange 63b extending laterally is provided on the outer surface of the drainage part 63a provided by narrowing the bottom part of the lower part 63, and a treatment liquid recovery tank 64 is connected to the flange 63b via an annular joint 69d. It is connected. As shown in FIG. 3, the inside of the drainage part 63a is a drainage hole 63c, and the fine particle dispersion that has been dispersed by the spray chamber 6 is passed through the drainage hole 63c in the treatment liquid recovery tank 9. It flows in through and is stored. By removing the treatment liquid recovery tank 9, the fine particle dispersion stored inside is recovered.

  A branch pipe 62a that forms an exhaust suction port 62b protrudes from the outer surface of the intermediate portion 62. A connection pipe 65 is connected to the branch pipe 62a via an annular joint 69e. The exhaust unit 8 is connected through a ring joint 69e. By operating the exhaust unit 8, the inside of the injection chamber 6 is sucked through the exhaust suction port 62 b, and the exhaust gas including the sucked mist is discharged from the exhaust duct 81. A drain tank 82 is connected to the lower portion of the exhaust unit 8 via an annular joint 69f, and the drain tank 82 stores the drain component in the exhaust sucked from the intermediate portion 62.

  As shown in FIG. 3, an inner surface flange 62 c protrudes inward in the vicinity of the upper end portion on the inner surface side of the intermediate portion 62, and a top plate 72 a provided at the upper end of the flow path regulating cylinder 72 is provided on the inner surface flange 62 c. Are combined. The flow path regulating cylinder 72 is a tubular member whose bottom is narrowed by a stepped portion having a different diameter, and is set by the top plate 72 a by setting the flow path regulating cylinder 72 inside the intermediate portion 62. A closed injection space 61b is formed in the upper part. A nozzle body 7a of the jet nozzle 7 attached to the nozzle holder 68 is inserted into the ejection space 61b from above.

  A collision portion 73 is provided on the top surface of the top plate 72a. The collision part 73 is provided with a collision member 73a having a collision surface 73b in the upper part. In a state where the collision member 73a is mounted on the top surface of the top plate 72a, the collision surface 73b is located immediately below the injection port 7b of the nozzle body 7a. By operating the jet nozzle 7 in this state, the micro droplet 33a ejected downward from the ejection port 7b collides with the collision surface 73b from above. Thereby, the aggregates 42 * (see FIG. 8) of the fine particles in the micro droplets 33a are dispersed by the physical energy of the impact force caused by the collision.

  Next, the structure of the jet nozzle 7 will be described with reference to FIG. As shown in FIG. 4, the jet nozzle 7 is mainly composed of a cylindrical nozzle body 7a, and an internal flow path hole 31 is formed through the nozzle body 7a in the longitudinal direction. The upstream side of the internal flow path hole 31 is an introduction part 31a to which the air supply pipe 10 is connected and compressed air (arrow a) that is a compressed gas is introduced. On the downstream side of the introduction part 31a, a convergent part 31b in which the flow path diameter of the internal flow path hole 31 is narrowed along the flow direction, a throat part 31c in which the flow path diameter is narrowed the smallest, and a divergent in which the flow path diameter increases. The part 31d and the accelerated cooling part 31e whose flow path diameter gradually increases are sequentially provided in the flow direction of the compressed air. The opening where the accelerated cooling part 31e reaches the end of the nozzle body part 7a serves as an injection port 7b for injecting a jet flow containing minute droplets.

  The jet nozzle 7 configured as described above forms a Laval nozzle having a convergent portion 31b, a throat portion 31c, and a divergent portion 31d. The nozzle body 7a is formed of a resin such as PTFE resin or a metal, and is manufactured by integrally molding one that is integrally formed or appropriately divided. The diameter of the throat portion 31c is appropriately set, for example, from a range of 3 to 10 mm, and the distance from the throat portion 31c to the injection port 7b is set to a distance sufficient for accelerating the compressed air in a range of 100 to 300 mm, for example. .

  That is, after the pressure is adjusted so that the throat portion 31c has a high speed of about the speed of sound, the compressed air is supplied to the convergent portion 31b at a subsonic speed (for example, about 50 m / sec) and accelerated by the convergent portion 31b. The sound velocity (about 330 m / sec) is obtained at the throat portion 31c, and further accelerated by the divergent portion 31d, for example, to a supersonic velocity of about 400 to 500 m / sec. A processing liquid supply pipe 32 that discharges the processing liquid 33 containing fine particles (see FIG. 7) in the same direction as the flow of compressed air is provided on the upstream side of the throat portion 31c. Here, the processing liquid 33 is supplied through the processing liquid supply pipe 11 in a predetermined amount set in advance. The supplied processing liquid 33 is discharged from the discharge port at the distal end of the processing liquid supply pipe 32 to become minute micro droplets 33a, and flows with the compressed air to the downstream side at a high speed.

  The discharge port of the treatment liquid supply pipe 32 is located in the vicinity of the throat portion 31c and away from the inner wall surface of the internal flow path hole 31, for example, the inner diameter of the throat portion 31c is 5 in the upstream direction and the downstream direction from the center of the throat portion 31c. It is arrange | positioned in the discharge outlet arrangement | positioning range which is less than the range of double length. In this way, by disposing the discharge port of the processing liquid supply pipe 32 in the vicinity of the throat portion 31c away from the inner wall surface of the nozzle main body portion 7a, the fine liquid droplet 33a in which the discharged processing liquid is atomized becomes the nozzle main body. This makes it less susceptible to the influence of the boundary layer region formed on the inner wall surface of the portion 7a, thereby suppressing the speed drop of the micro droplet 33a and sufficiently accelerating it.

  The jet acceleration process in the jet nozzle 7 will be described. The flow of compressed air supplied to the introduction portion 31a as drive air at a set pressure (for example, 0.5 MPa) is first accelerated by the convergent portion 31b (arrow b), and passes through the throat portion 31c at a flow velocity about the speed of sound. Then, by moving from the throat portion 31c into the divergent portion 31d, the pressure is reduced and further accelerated (arrow c). Then, the fine droplets 33a discharged from the discharge port of the processing liquid supply pipe 32 and atomized by the flow of compressed air flow at a high speed downstream (according to the arrow d) while being accelerated in the accelerating cooling unit 31e that gradually expands in diameter. ) And jetted from the jet port 7b of the jet nozzle 7. The degree of diameter expansion in the accelerated cooling portion 31e is determined in consideration of the thickness of the boundary layer region formed near the inner wall surface of the internal flow path hole 31.

  In general, in the flow of fluid in a circular pipe, a boundary layer in which the flow state changes near the inner wall surface of the pipe, and the flow velocity decreases in this boundary layer region. In the case of a flow in a circular pipe having a constant pipe inner diameter, the boundary layer region expands in the vicinity of the pipe outlet, resulting in a decrease in the flow velocity near the center of the flow. On the other hand, by providing the acceleration cooling part 31e that gradually expands in the flow direction in consideration of the boundary layer region, it is possible to suppress the influence of a decrease in the flow velocity in the boundary layer region, and to increase the speed even in the vicinity of the injection port 7b. The flow can be secured in a wide range. The jet nozzle 7 and the air supply source 5 configured as described above constitute droplet accelerating means for accelerating and ejecting the micro droplet 33a at least one time the speed of sound.

  In addition, in the ejection chamber 6, not only the above-described Laval nozzle type jet nozzle 7, but also two-fluid nozzle type jet nozzles 7A and 7B shown in FIGS. 5 and 6 can be used as droplet accelerating means. The jet nozzle 7 and the jet nozzles 7A and 7B have a dispersion difficulty and a desired dispersion mode of the material to be dispersed, that is, required uniformity of particle size distribution and damage allowed to the fine particles after the dispersion treatment. It is selectively attached according to the degree. Dispersion difficulty here is not a strictly defined concept, but it is broken down to the same particle size by physical means, ie, the binding strength of the target substance. It can be considered that it means the magnitude of the physical force required to disperse. The degree of dispersion difficulty does not necessarily correspond to a characteristic value such as the hardness of a substance, and is currently determined from the result of actually trying dispersion processing individually.

  The jet nozzle 7 is used when a predetermined speed defined according to the degree of dispersion difficulty determined by the type of fine particles to be dispersed and the desired dispersion mode is equal to or higher than the sound speed. That is, when the fine particles to be dispersed are solid species having a strong binding force and the degree of atomization difficulty is high, the jet nozzle 7 is selectively used. On the other hand, the jet nozzles 7A and 7B are selected when the above-described predetermined speed is in a speed range lower than the sound speed.

  First, the structure of the jet nozzle 7A will be described. In FIG. 5, the jet nozzle 7 </ b> A is obtained by changing the flow path cross-sectional shape on the downstream side from the throat portion 31 c in the jet nozzle 7. That is, the upstream configuration from the throat portion 31c is the same as that of the jet nozzle 7, and driving air (arrow a), which is compressed gas, is introduced into the introduction portion 31a to which the air supply piping 70 is connected, and the processing liquid supply piping. The processing liquid 33 supplied from 71 via the processing liquid supply pipe 32 is discharged from the discharge port of the processing liquid supply pipe 32 arranged on the upstream side of the throat portion 31c.

  The drive air introduced into the introduction part 31a is accelerated by the convergent part 31b whose flow path diameter is restricted along the flow direction (arrow b), and has the highest flow velocity at the throat part 31c where the flow diameter is restricted to the smallest. It becomes larger and is ejected into the acceleration part 31f (arrow c). Here, the pressure of the drive air supplied to the introduction part 31a is set so that the flow velocity in the throat part 31c is less than the sound speed. At this time, the processing liquid 33 discharged from the processing liquid supply pipe 32 into the gas flow of the driving air is miniaturized to become micro droplets 33a, is accelerated together with the driving air, and flows into the acceleration unit 31f (arrow d). . Since the acceleration part 31f is provided with the same flow path diameter from immediately after the throat part 31c to the injection port 7b, the flow is accelerated by the flow path shape like the divergent part 31d and the acceleration cooling part 31e in the jet nozzle 7. It does not have a function, and it stops at the function of guiding and surrounding the flow. Therefore, in the jet nozzle 7A, the micro droplet 33a is ejected from the ejection port 7b at a speed lower than the speed of sound.

  Next, the structure of the jet nozzle 7B will be described. In FIG. 6, the jet nozzle 7 </ b> B mainly includes a cylindrical nozzle main body portion 7 a, and an internal flow path hole 74 is formed in the nozzle main body portion 7 a so as to penetrate in the longitudinal direction. The upstream side of the internal flow path hole 74 is an introduction part 74a to which the air supply pipe 70 is connected and the drive air (arrow f) is introduced. On the downstream side of the introduction part 74a, a convergent part 74b in which the flow path diameter of the internal flow path hole 74 is narrowed along the flow direction is provided, and downstream of the throat part 74c with the smallest flow path diameter. The acceleration part 74d is provided with the same flow path diameter from immediately after the throat part 74c to the injection port 7b. A processing liquid supply pipe 75 for supplying a processing liquid (arrow e) is inserted into the internal flow path hole 74 from the upstream side in the same manner as the processing liquid supply pipe 71, and a distal end portion 75 a of the processing liquid supply pipe 75 is a throat. It has reached part 74c. The discharge port provided in the tip portion 75a is disposed in the throat portion 74c.

  The drive air introduced into the introduction part 74a is accelerated by the convergent part 74b (arrow g), and the flow velocity becomes maximum at the throat part 74c and is ejected into the acceleration part 74d (arrow h). Here, similarly to the jet nozzle 7A, the pressure of the driving air supplied to the introduction portion 74a is set so that the flow velocity in the throat portion 74c is less than the sound velocity. At this time, the treatment liquid 33 discharged from the discharge port of the tip end portion 75a into the gas flow of the driving air is miniaturized to become a minute droplet 33a, is accelerated together with the driving air, and is jetted into the acceleration unit 74d (arrow i). ), And then flows downstream in the accelerating portion 74d (arrow j).

  Since the acceleration part 74d is provided with the same flow path diameter from immediately after the throat part 74c to the injection port 7b, the flow is accelerated by the flow path shape like the divergent part 31d and the acceleration cooling part 31e in the jet nozzle 7. It does not have a function, and it stops at the function of guiding and surrounding the flow. Accordingly, in the jet nozzle 7B as well, as in the case of the jet nozzle 7A, the micro droplet 33a is ejected from the ejection port 7b at a speed lower than the speed of sound.

  That is, the jet nozzles 7A and 7B constituting the droplet accelerating means together with the gas supply means for supplying the driving air in the flow direction of the internal flow path holes 31 and 74 are formed in a circular shape with the internal flow path holes 31 and 74 narrowed down. Nozzle body 7a in which straight pipe-shaped acceleration parts 31f and 74d are connected to the downstream side of the throat parts 31c and 74c in cross section, and the treatment liquid provided in the nozzle body 7a and supplied in the same direction as the flow direction is discharged. The discharge ports of the processing liquid supply pipes 32 and 75 are arranged upstream of the throat part 31c or in the throat part 74c in the internal flow path holes 31 and 74. Yes.

  With such a configuration, as described above, the processing liquid 33 discharged from the processing liquid supply pipe 32 has a function of accelerating the fine liquid droplet 33a to a speed lower than the sound speed and ejecting it from the ejection port 7b. doing. For this reason, the jet nozzles 7A and 7B are used when the aforementioned predetermined speed is lower than the sound speed. That is, when the dispersion difficulty of the fine particles to be dispersed is low, the jet nozzle 7A or the jet nozzle 7B is selectively used.

  By employing the jet nozzles 7A and 7B having such a configuration, it is possible to reduce the cost of the droplet accelerating means used in the fine particle dispersion manufacturing apparatus. That is, when various kinds of substances including gel-like substances are considered as dispersion treatment targets, the impact force required for the dispersion treatment varies within a wide range. Therefore, the droplet accelerating means is not necessarily limited to a Laval nozzle type jet nozzle that can be accelerated to the supersonic range, and a general two-fluid nozzle that is inexpensive to manufacture can be used. In the Laval nozzle, it is necessary to precisely process the cross-sectional shape of the flow path according to the theoretical shape represented by the mathematical formula, and thus it is difficult to avoid an increase in manufacturing cost.

  On the other hand, in the case of a general two-fluid nozzle, fine droplets generated by supplying a treatment liquid containing fine particles in a gas flow generated by restricting the flow path of driving air can be ejected. Any type of two-fluid nozzle can be used as long as the droplet can be accelerated to a predetermined speed according to the dispersion difficulty of the substance to be dispersed and the desired degree of dispersion. Also good. For example, in the jet nozzle 7A, an example in which the flow path cross-sectional shape is the same as that of the convergent portion 31b and the throat portion 31c in the jet nozzle 7 which is a Laval nozzle is shown, but depending on the required speed, A simplified channel cross-sectional shape such as the convergent portion 74b and the throat portion 74c in 7B may be employed.

  By applying the jet nozzle 7 and the jet nozzles 7A and 7B having the above-described configuration to the atomization process, the following special effects can be obtained based on the characteristics of these configurations. That is, in the jet nozzle 7 and the jet nozzles 7A and 7B, the driving air flowing downstream through the internal flow path hole 31 and the internal flow path hole 74 is insulated when flowing from the throat portion 31c and the throat portion 74c to the downstream side. It has the characteristic that the temperature decreases due to expansion. Thereby, the micro droplet 33a is ejected from the ejection port 7b in a cooled state. In particular, in the jet nozzle 7, the cooling effect is remarkable because the divergent portion 31 d and the accelerated cooling portion 31 e are further provided on the downstream side.

  Such a cooling effect has an extremely important role in efficiently performing the distributed processing intended in the present invention with high quality. That is, heat generation due to friction is unavoidable in a dispersion treatment method used for the same purpose in the prior art, for example, a dispersion treatment by physical contact with a medium such as a ball or bead such as a dispersion treatment using a ball mill or a bead mill. If the treatment is continued while the temperature of the material to be dispersed is increased due to heat generation, a mechanical alloying phenomenon occurs in which fine particles once dispersed are aggregated again, and an appropriate dispersion purpose cannot be achieved. For this reason, the conventional distributed processing method has a problem in that the processing efficiency is extremely limited because it is necessary to perform processing within a range in which excessive temperature rise due to heat generation does not occur. The limit of the processing efficiency due to the temperature rise due to the heat generation is common in the fine particle dispersion method in which the fine particles in the jet jet pressurized to a high pressure collide with each other.

  On the other hand, as shown in the present invention, in the dispersion process using the jet nozzle 7 and the jet nozzles 7A and 7B, as described above, the micro droplet 33a including the dispersion process target is always cooled and the collision unit 73 is in a cooled state. Collide with. Therefore, even if the fine particles dispersed by collision generate heat due to energy conversion by collision, the fine particles are heated to a temperature at which the normal dispersion process is hindered by this heat generation, that is, a temperature at which the fine particles cause reaggregation. The temperature will not rise. Moreover, such a cooling effect is realized by the inherent characteristics of the jet nozzle 7 and the jet nozzles 7A and 7B without adding any additional components such as an external cooling device. Distributed processing can be performed with high efficiency while realizing simplification of configuration and reduction of equipment costs.

  Next, the configuration of the piping system will be described with reference to FIG. In FIG. 7, the jet nozzle 7 (jet nozzles 7 </ b> A and 7 </ b> B) is connected to the air supply source 5 via an on / off valve 81 by an air supply pipe 70. A pressure switch 82 is connected to the air supply pipe 70 between the on / off valve 81 and the air supply source 5. The air supply source 5 has a function of supplying clean air that does not contain oil mist and moisture, and the on / off valve 81 is controlled by a control unit (not shown), whereby the air supply source 5 supplies the jet nozzle 7. The supply of driving air is turned on and off. The pressure switch 82 detects the pressure of the driving air supplied from the air supply source 5. The air supply source 5 and the air supply pipe 70 constitute gas supply means for supplying driving air that is compressed gas in the flow direction of the internal flow path holes of the jet nozzle 7 and the jet nozzles 7A and 7B.

  Further, the air supply source 5 is connected to the processing liquid storage unit 2 via a pressure pipe 83. A regulator 85, a mass flow controller 86, an on / off valve 87, and a check valve 88 are interposed in the pressurizing pipe 83 from the air supply source 5 side. The pressure pipe 83 has a pressure between the regulator 85 and the air supply source 5. A switch 84 is connected. By controlling the on / off valve 87 by a control unit (not shown), the supply of pressurizing air from the air supply source 5 to the treatment liquid storage unit 2 is turned on / off. The regulator 85 adjusts the pressure of the air supplied to the processing liquid storage unit 2 to a set specified pressure. The mass flow controller 86 controls the flow rate of air supplied from the air supply source 5 to the processing liquid storage unit 2 to a constant value. The check valve 88 prevents the air from flowing back from the processing liquid reservoir 2 side to the air supply source 5 side in the pressurizing pipe 83. The pressure switch 84 detects the pressure of driving air supplied from the air supply source 5 to the processing liquid storage unit 2.

  The treatment liquid storage unit 2 is a sealed container capable of storing an untreated treatment liquid 33 containing fine particles in an aggregated state therein, and the viscosity of the liquid 33b is equal to or higher than a lower limit reference viscosity defined in advance by the viscosity adjustment unit 3. The adjusted processing liquid 33 is stored. The pressurizing pipe 83 communicates with a pressurizing space 90 a formed above the liquid level of the processing liquid 33 in the processing liquid storage unit 2. The treatment liquid storage unit 2 includes a push pipe 92 that opens at a position lower than the liquid level of the treatment liquid 33 stored therein, and the push pipe 92 is provided with a treatment liquid supply pipe 71 led to the jet nozzle 7. And is connected through an on / off valve 89.

  By opening the on / off valve 87 and supplying air for pressurization from the air supply source 5 into the pressurizing space 90a, the processing liquid 33 in the processing liquid storage section 2 is pushed in from the opening at the lower end by pressure. It is pushed in and is further pumped through the pushing tube 92. Then, the processing liquid 33 is supplied to the jet nozzle 7 by opening the on / off valve 89. At this time, the processing liquid 33 can be supplied into the gas flow in the internal flow path hole 31 and the internal flow path hole 74 of the jet nozzle 7 at a specified pressure and flow rate by setting the regulator 85 and the mass flow controller 86. Therefore, the air supply source 5, the pressurizing pipe 83, and the processing liquid storage unit 2 constitute processing liquid supply means for supplying a processing liquid containing fine particles into the gas flow.

  Next, referring to FIG. 8, FIG. 9, and FIG. 10, the processing apparatus 33 containing the agglomerated fine particles 42 in the liquid is caused to collide with the collision part 73 by the fine particle dispersion manufacturing apparatus 1, thereby producing fine particles. A method for producing a fine particle dispersion for producing a fine particle dispersion dispersed in a liquid will be described.

FIG. 8A shows the treatment liquid 33 before the dispersion treatment. The treatment liquid 33 contains an aggregate 42 * in which a plurality of fine particles 42 are aggregated in the liquid 33b. The fine particles 42 used in the present invention are not limited, and include metal powders, intermetallic compound powders, ceramic powders such as oxides, carbides, and nitrides, organic compounds, and mixed powders thereof. In particular, it contains a metal (for example, silver, copper, tin, zinc, platinum, nickel, palladium, lithium) or a compound thereof that has a property of deteriorating characteristics when damage such as lattice strain is given to the inside of the particle. Fine particles and fine particles that do not allow damage to the particle surface are preferably used. The particle diameter of the fine particles can be widely used from nano size to micron size, but is preferably in the range of 10 to 10 ⁴ nm.

  The liquid 33b used for the treatment liquid 33 is water, hydrocarbons, alcohols, ethers, ketones, esters, carboxylic acids, phenols, nitrogen-containing compounds, sulfur-containing compounds, fluorine compounds, inorganic solvents It is preferable to use what has been conventionally used for fine particle dispersions, such as the like, and these may be mixed if necessary. Furthermore, a known additive may be blended for the purpose of adjusting the viscosity of the liquid and / or for maintaining the dispersed state of the fine particles after the dispersion treatment. Known additives include, for example, anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, polymer surfactants, silicone surfactants, and fluorine surfactants. It is preferable to add a necessary amount of an additive capable of achieving the above object. Further, the pH of the liquid may be controlled within a range in which the fine particle dispersion state after the dispersion treatment can be maintained.

  The concentration of the fine particles 42 contained in the treatment liquid 33 is such that the ratio of the fine particles colliding with the collision portion is a predetermined ratio or less, and the outer shape generated in the fine particles due to the collision with the collision portion in the particle dispersion step. The deformation and the internal lattice strain may be adjusted so as to be less than the desired degree, but it is preferably approximately 50 vol% or less. When the concentration of the fine particles is 50 vol% or more, the rate at which the fine particles collide with the collision portion increases.

  Preparation of the treatment liquid 33 is performed by first mixing one or more kinds of solvents and, if necessary, an additive by a known method, stirring, and further dissolving if the additive is a solid, and setting a lower limit standard set in advance. A liquid 33b having a viscosity or higher is prepared. The viscosity here is an intrinsic viscosity obtained from a slope obtained by Casson plotting a shear rate and a shear stress measured at 25 ° C. using a rotary rheometer.

In the present invention, the shear stress measured in the range of a shear rate of ¹ to 1000 sec ⁻¹ using a cone type measuring jig having a diameter of 50 mm and a cone angle of 1 ° with a rotational rheometer of Physica MCR301 manufactured by Anton Paar. The intrinsic viscosity was determined by Casson plot. In an actual use environment, substitute by correlating a rotary rheometer with a device that can easily measure viscosity, such as a B-type viscometer, vibration-type viscometer, tuning-fork-type vibration viscometer, capillary viscometer, etc. be able to.

  The mixing, stirring, and dissolution methods for liquid preparation are not particularly limited as long as a uniform liquid is obtained. For example, a propeller-type mixer, mechanical stirrer, shaker, high-speed rotary mixer, ultrasonic homogenizer, or the like is used. Next, a predetermined amount of fine particles 42 are weighed, mixed and stirred in the liquid 33b. Here, the liquid 33b and the fine particles 42 may be a known mixing and stirring device, but a shearing strength mixing and stirring device that does not increase lattice strain inside the fine particles must be used. The series of treatment liquids may all be prepared by the viscosity adjusting unit 3, or only the final liquid 33b and the fine particles 42 may be mixed and stirred. This is because heating may be performed when the additive is dissolved in the preparation of the liquid 33b. The process liquid 33 is obtained through the above process (viscosity adjustment process). The purpose of this viscosity adjustment process is to suppress damage to the fine particles 42 as much as possible during the dispersion process as described above.

  That is, the damage to the fine particles 42 is caused by an excessive impact force acting on the aggregate 42 * due to the collision of the fine liquid droplets 33a with the collision surface 73b. What is necessary is just to set the process conditions which make the impact force required for crushing and dispersion | distribution act on the aggregate 42 *, without making the aggregate 42 * collide directly with the collision surface 73b at the time of the collision of the droplet 33a. Since the inventor has already experimentally obtained the knowledge that it is a shock wave excited inside the droplet when the micro droplet 33a collides, which contributes to the crushing / dispersion of the aggregate 42 *. New knowledge that it is effective to use high-viscosity liquid as the liquid 33b constituting the treatment liquid 33 and to suppress the movement of the aggregates 42 * inside the microdroplets 33a in order to satisfy the appropriate treatment conditions As found.

  Specifically, the rate at which the microparticles 42 in the micro droplet 33a collide with the collision surface 73b of the collision unit 73 is less than a predetermined rate defined by the degree of allowable damage, and the collision surface 73b Also for the fine particles 42 that have collided via the fine droplets 33a, the liquid is deformed so that the deformation of the outer shape and the internal lattice distortion generated in the fine particles 42 due to the collision are less than the desired degree based on the allowable damage. Adjust the viscosity of 33b.

  Here, a lower limit reference viscosity as a lower limit of the viscosity satisfying such a condition is set as a parameter (for example, a physical force exerted on the micro droplet 33a by the kind of the fine particles 42 and the gas flow by the jet nozzles 7, 7A, 7B. In the process of continuing the dispersion process, the liquid 33b is always higher than the lower reference viscosity by the function of the viscosity adjusting unit 3 in the process of continuing the dispersion process. Adjust so that As specific methods for adjusting the viscosity, various methods such as a method of selectively using a plurality of types of liquids having different viscosities and a method of appropriately blending a thickening component for increasing the viscosity into a single type of liquid may be used. it can.

  That is, in this viscosity adjustment process, the ratio of the fine particles 42 colliding with the collision part 73 in the droplet collision process described below is equal to or less than a predetermined ratio, and is caused by the collision with the collision part 73 in the particle dispersion process. Thus, the parameters for defining the lower limit reference viscosity and the physical force exerted on the micro droplets 33a by the kind of the fine particles 42 and the gas flow so that the deformation of the outer shape generated in the fine particles 42 and the internal lattice distortion are less than the desired degree. Set according to. In addition, the setting of the lower limit reference viscosity is a so-called dispersion treatment result which is evaluated while systematically changing the above-described parameters for defining the physical force and the viscosity of the liquid 33b for each material type of the target fine particles 42. It is required by condition setting work. For example, when crushing / dispersing with a supersonic gas flow by the jet nozzle 7 for copper fine particles which are ductile metals, 10 mPa · s can be used as the value of the lower limit reference viscosity.

  The processing liquid 33 whose viscosity is adjusted in this way is stored in the processing liquid storage unit 2 and then supplied to the jet nozzle 7. That is, in FIG. 9A, first, driving air is supplied to the internal channel hole 31 at a set pressure (for example, 0.5 MPa) (arrow a). As a result, the downstream portion from the internal flow path hole 31 is first accelerated by the convergent portion 31b (arrow b) and passes through the throat portion 31c as a jet having a flow velocity of about the speed of sound. In this state, the processing liquid 33 including the fine particles 42 which are pumped from the tank 17 by the pump 18 and sent to the jet nozzle 7 through the processing liquid supply pipe 11 is transferred from the processing liquid supply pipe 32 to the throat portion 31c to the microdroplet 33a. And is supplied into a gas flow (liquid supply step).

  Next, as shown in FIG. 9B, the gas flow including the minute droplets 33a moves from the throat portion 31c into the divergent portion 31d, so that the pressure is lowered and further accelerated (arrow c). The fine droplets 33a discharged from the discharge port of the processing liquid supply pipe 32 and atomized to about 5 to 15 μm by the gas flow are accelerated while being accelerated to a flow velocity exceeding the speed of sound in the accelerating cooling section 31e gradually expanding in diameter. (Arrow d). That is, the supplied processing liquid 33 is converted into microdroplets by a gas flow and accelerated (droplet acceleration step).

  Next, as shown in FIG. 9C, the micro droplet 33a accelerated in this way is ejected from the ejection port 7b of the jet nozzle 7 to the collision portion 73, and the ejected micro droplet 33a collides. It is made to collide with the collision surface 73b of the part 73 at high speed (droplet collision process). As a result, the agglomerated fine particles 42 contained in the microdroplets 33a are dispersed by a shock wave excited in the microdroplets 33a by collision (particle dispersion step). That is, the agglomerated fine particles 42 are crushed and dispersed by the shock wave, and as shown in FIG. 8B, a fine particle dispersion 33 * containing the fine particles 42 in a dispersed state in the liquid 33b is produced.

  At this time, by performing the crushing treatment with the liquid 33b having a viscosity equal to or higher than the lower limit reference viscosity as described above, the particle size of the aggregate 42 * in the liquid 33b after the particle dispersion step is obtained as shown in FIG. The ratio (Da / Dc) of the particle diameter (Dc) of the fine particles 42 measured by (Da) and SEM observation can be made smaller than 1.2, and better dispersibility is realized.

  Here, a mechanism of dispersion by crushing the fine particles 42 in the above-described droplet collision step and particle dispersion step will be described with reference to FIG. As shown in FIG. 10A, the micro droplet 33 a that is ejected from the jet nozzle 7 and collides with the collision surface 73 b of the collision unit 73 includes a plurality of fine particles 42 and aggregates of the fine particles 42. These fine particles 42 are about 10 μm for large ones and about 10 nm for small ones, and the sizes are in a wide range. When such a micro droplet 33a collides with the collision part 73 at high speed, a relatively large particle 42 included in the micro droplet 33a collides with the collision surface 73b due to inertial force, and due to impact energy due to the collision. It is crushed and dispersed in the fine particles 42a.

  On the other hand, since the inertial force of particles having a small size is likely to be reduced by the viscosity of the fine droplets 33a, impact energy due to the collision of the particles themselves with the collision surface 73b is less likely to act directly. The particles having such a small size are subjected to a dispersion process of the fine particles 42 by a shock wave generated inside the micro droplet 33a by the collision with the collision surface 73b acting as a vibration. That is, as shown in FIG. 10B, a shock wave 43 propagating from the collision interface to the inside due to the collision with the collision surface 73b is instantaneously generated inside the microdroplet 33a, The fine particles 42 having a small particle size are further crushed and dispersed into nano-sized particles having a particle size of about 1 nm to 1000 nm.

  In order to stably realize the dispersion processing action due to the collision of the minute droplets 33a, the velocity of the minute droplets 33a ejected from the jet nozzle 7 is made as high as possible to enter the collision surface 73b. It is necessary. In the present invention, the fine droplets 42a to be dispersed are contained in the microdroplets 33a as carriers, and the microdroplets 33a are used as a accelerating medium. The effect is gained.

  As shown in FIG. 10C, the behavior of the fluid when jetting a jet having a predetermined jet width against the solid wall (here, the collision surface 73b) is such that the incident flow 44 (arrow f) is applied to the collision surface 73b. After being incident, it becomes a dispersed flow 44a (arrow g) that scatters radially along the collision surface with the incident position as the center and diffuses to the periphery. In this flow model, when the fluid is a liquid having a high density and viscosity, the fine particles 42 to be atomized are strongly diffused to the surroundings while being contained in the dispersed flow 44a, and most of the fine particles 42 collide. Do not collide directly with the surface.

  On the other hand, when the fine particles 42 to be atomized are contained in the micro droplet 33a as the carrier and the micro droplet 33a is used as the accelerating medium as in the present invention, the incident flow 44 is used at high speed. Since the transported micro droplets 33a are gas and the viscosity and density are low, most of the micro droplets 33a collide with the collision surface 73b while maintaining high speed without being involved in the dispersed flow 44a. Therefore, it is possible to effectively use physical energy obtained by accelerating the fine droplets 33a for crushing / dispersing the fine particles 42. At this time, by evacuating the periphery of the collision part 73 and quickly diffusing the dispersed flow 44a, it is possible to eliminate as much as possible the adverse effect that the dispersed flow 44a prevents the microdroplets 33a from colliding with the collision surface 73b. In the present embodiment, since the above-described exhaust means is provided, it is possible to quickly exhaust the dispersed flow 44a to further improve the working efficiency of the crushing / dispersing process.

  Furthermore, in this embodiment, since the viscosity of the liquid 33b constituting the fine droplet 33a is adjusted to be equal to or higher than the above-mentioned lower limit reference viscosity in the viscosity adjusting step, the fine particles such as deformation of the fine particles 42 and internal lattice strain can be obtained. It is possible to reduce damage that impairs product characteristics. An experimental example in which the effect of suppressing dispersibility and damage suppression by adjusting the viscosity will be described with reference to FIGS. 11, 12, and 13.

  Here, Cu (copper) fine particles having a particle diameter Dc of 1.5 μm, which will be described later, are used as the fine particles 42, and ethanol and dihydroterpineol having viscosities of 1.08 mPa · s and 57.1 mPa · s, respectively, are used as the low-viscosity liquid. It is used as a highly viscous liquid. Then, a slurry-like liquid in which Cu fine particles are contained in these liquids at a concentration of 5 vol% is used as the treatment liquid 33, and the flow rate is 100 ml / min. The result of the experiment example which repeatedly performed the dispersion | distribution process pass 5 times on the conditions of the air injection pressure 0.6MPa in the jet nozzle 7 is shown.

  First, FIG. 11A shows an SEM observation photograph in which untreated Cu fine particles are magnified 10,000 times. FIGS. 11B, 11B, and 11B show SEM observation photographs and grains after repeating the dispersion treatment pass 5 times by containing Cu fine particles in a high-viscosity liquid and a low-viscosity liquid, respectively, as a treatment liquid 33. The diameter distribution is shown.

  In the SEM observation, an observation sample obtained by dropping the treatment liquid onto an aluminum foil using a pipette and vacuum drying was observed with a scanning electron microscope (S-4800, manufactured by Hitachi, Ltd.), and image analysis software (Vision Stage IP, manufactured by Alliance Vision). The median diameter of the particle size distribution obtained by using was used as the particle diameter Dc of the fine particles 42 shown in FIG.

  The particle size distribution is 50% of the cumulative curve obtained by accumulating the volume frequency of the particle size obtained using the Microtrack particle size distribution measuring apparatus (MX3300EXII) manufactured by Nikkiso Co., Ltd., and Da shown in FIG. . When the maximum particle size of the fine particles is smaller than 1 μm, the particle size distribution based on the scattered light intensity measured by a dynamic light scattering particle size distribution analyzer (for example, Zetasizer NANO-ZS manufactured by Malvern) is used. The average particle diameter obtained by the method described in JIS Z8826 can be defined as Da.

  In the example using the high-viscosity liquid shown in (a), no change is observed on the particle surface even after the dispersion treatment pass is executed five times. However, in the example using the low-viscosity liquid shown in (b), the dispersion is performed. A fine deformation is observed in the particle shape after the processing pass is executed five times.

  In the particle size distribution, in the example using the low-viscosity liquid shown in (b), the distribution state tended to change in the direction of increasing the particle size, and reaggregation of Cu fine particles was observed in part. . On the other hand, in the example using the highly viscous liquid shown in (a), it can be seen that even when the number of passes is increased, the particle size distribution is stable, and the crushed and dispersed state is maintained.

  Next, the relationship between the viscosity of the liquid and the lattice strain generated in the Cu fine particles will be described with reference to FIG. FIG. 12A illustrates changes in the number of lattice strain collisions, that is, the number of dispersion processing passes, when a low-viscosity liquid and a high-viscosity liquid are used as liquids, respectively. As can be seen from this graph, when a highly viscous liquid is used, the lattice strain is between 0.1 and 0.15% (0.001 to 0.0015) even when the number of collisions reaches 5. It remains at almost the same numerical level. This means that the lattice strain in the fine particles after the particle dispersion step is desirably 0.002 or less, and further, the change in the lattice strain in the fine particles before and after the particle dispersion step is desirably 0.0005 or less. It shows that the results satisfying the quality standard were obtained.

The lattice strain described above was determined by the Williamson-Hall method from the powder X-ray diffraction profile of the fine particles. In the above method, the lattice strain can be obtained based on the following formula (1).
βcos θ / λ = 2η (sin θ / λ) + K / D (1)

Here, β: half width, θ: Bragg angle of diffraction line, η: lattice strain, D: crystallite diameter, K: Scherrer constant, λ: X-ray wavelength. The measurement conditions in the present invention are as follows.
X-ray diffractometer: X'Pert PRO MPD manufactured by PANalytical
X-ray used: CuKα1 ray (wavelength: 1.54060 mm)
X-ray output: 45kV-40mA
Divergence slit: 1 °
Scattering slit: variable slit (anti-scatter slit)
Light receiving slit: 0.1 mm
Light receiving unit: Semiconductor detector with monochromator (X'Celerator)
Measurement angle range (2θ): 40 to 120 °
Step size (2θ): 0.01 °
Scan step time: 10 sec.

  The half-width and Bragg angle of the six diffraction peaks appearing within the measurement angle range were plotted, and the lattice strain was determined from the slope of the approximate expression obtained by linear approximation by the least square method. In order to remove the influence of the apparatus from the measured value, a value corrected using standard silicon powder was used for the half width.

  FIGS. 13A and 13B show diffraction profiles when a high-viscosity liquid and a low-viscosity liquid are used as liquids, respectively. In the diffraction profile when a highly viscous liquid is used, it can be seen that the peak shape in the profile is maintained even when the number of dispersion processing passes is increased, and the lattice distortion is small. On the other hand, in the example using the low-viscosity liquid shown in FIGS. 13B, 13A and 13B, the diffraction profile changes and the peak shape tends to disappear each time the number of dispersion processing passes is increased. It can be seen that the strain is increased.

  FIG. 12B shows the influence of the gas stream injection pressure on the lattice strain in the fine particles when a low viscosity liquid is used. As can be seen from this graph, as the injection pressure is increased to 0.4 MPa, 0.6 MPa, and 1.5 MPa, the lattice strain increases each time the number of dispersion treatment passes is increased. When this result is compared with the graph shown in FIG. 12A, it can be seen that it is extremely effective to use a high-viscosity liquid in suppressing lattice distortion in the crushing / dispersing treatment.

  As described above, in the present embodiment, a fine particle dispersion in which the liquid 42 is dispersed in the liquid by colliding the liquid to be treated 33 containing the fine particles 42 in an agglomerated state in the liquid 33b with the collision unit 73. , The degree of collision of the fine particles 42 with the collision portion 73 is equal to or less than a predetermined ratio, and the degree of deformation of the outer shape and the internal lattice distortion generated in the fine particles 42 due to the collision with the collision portion 73 are a desired degree. As described below, the viscosity of the liquid 33b is adjusted to be equal to or higher than the lower limit reference viscosity set in accordance with the parameters that define the type of the fine particles 42 and the physical force that the gas flow exerts on the microdroplets 33a. Thereby, the impact caused by the direct collision of the fine particles 42 in the liquid 33b with the collision portion 73 is suppressed, and the fine particle dispersion is efficiently manufactured without damaging the fine particles 42 such as deformation and internal lattice distortion. be able to.

  The method for producing a fine particle dispersion of the present invention has the advantage that the fine particle can be efficiently dispersed without causing damage such as deformation and internal lattice distortion, and a fine particle dispersion in which fine particles are dispersed in a liquid. Useful in the field of manufacturing.

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus of fine particle dispersion 2 Processing liquid storage part 3 Viscosity adjustment part 4 Dispersion processing part 6 Injection chamber 7, 7A, 7B Jet nozzle 9 Processing liquid collection | recovery tank 33 Processing liquid 33 * Processed liquid 33a Minute droplet 33b Liquid 42 Fine particle 42 * Aggregate 73 Colliding part

Claims (8)

A method for producing a fine particle dispersion, wherein a fine particle dispersion in which the fine particles are dispersed in the liquid is produced by colliding a liquid to be treated containing fine particles in an aggregated state in a liquid with a collision portion,
A viscosity adjusting step for adjusting the viscosity of the liquid in the liquid to be processed to be equal to or higher than a preset lower limit reference viscosity;
A liquid supply step of supplying the liquid to be treated into a gas flow;
A droplet accelerating step for accelerating and accelerating the supplied processing target liquid into microdroplets by a gas flow;
A droplet collision step for causing the accelerated micro droplet to collide with the collision portion;
A particle dispersion step of dispersing the agglomerated fine particles by a shock wave excited in the microdroplet by the collision,
In the viscosity adjustment step, the ratio of the fine particles colliding with the collision portion in the droplet collision step is equal to or less than a predetermined ratio, and in the particle dispersion step, these fine particles are caused to collide with the collision portion. The lower reference viscosity is set according to parameters defining the kind of fine particles and the physical force that the gas flow exerts on the fine droplets, so that the resulting deformation of the outer shape and the internal lattice strain are less than the desired degree. A process for producing a fine particle dispersion characterized by the above.   The method for producing a fine particle dispersion according to claim 1, wherein the gas flow is a supersonic air flow, and the lower limit reference viscosity at 25 ° C is 10 mPa · s.   The method for producing a fine particle dispersion according to claim 1 or 2, wherein a lattice strain in the fine particles after the particle dispersion step is 0.002 or less.   The ratio (Da / Dc) of the particle size (Da) of the fine particles in the liquid after the particle dispersion step and the particle size (Dc) measured by SEM observation is smaller than 1.2. Item 4. A method for producing a fine particle dispersion according to any one of Items 1 to 3.   The method for producing a fine particle dispersion according to any one of claims 1 to 4, wherein a change in lattice strain in the fine particles before and after the particle dispersion step is 0.0005 or less. The droplet accelerating step includes a convergent portion provided with the flow passage diameter of the internal flow passage hole narrowed in the flow direction, and a diameter expanded in the flow direction downstream of the throat portion having a circular cross section with the smallest flow passage diameter. A nozzle body portion of a Laval nozzle type in which a divergent portion and an accelerated cooling portion which is located downstream of the divergent portion and whose flow passage diameter gradually increases is formed, and compressed gas is supplied in the flow direction of the internal flow passage hole Gas supply means, and a solution supply pipe that is provided in the nozzle body and discharges the supplied solution in the same direction as the flow direction,
The discharge port of the solution supply pipe is disposed at a position away from the inner wall side surface of the nozzle main body part and within a length range of five times the inner diameter of the throat part from the center of the throat part to the downstream side, and the throat The diameter of the part is set in a range of 3 to 10 mm, and the distance from the throat part to the injection port in which the accelerated cooling part is opened at the end of the nozzle body part is 100 to 300 mm. The method for producing a fine particle dispersion according to any one of claims 1 to 5.   The method for producing a fine particle dispersion according to any one of claims 1 to 6, wherein the fine particles contain a metal that easily undergoes plastic deformation or a compound thereof.   The method for producing a fine particle dispersion according to claim 7, wherein the metal is any one of silver, copper, tin, zinc, platinum, nickel, palladium, and lithium.