JP4956095B2 - Media stirring type wet disperser - Google Patents

Description

  The present invention relates to a media agitation type wet disperser that performs continuous dispersion treatment, and more particularly, to a media agitation type wet disperser that can obtain a dispersion composed of fine particles of nanometer order. The present invention also relates to a method for dispersing fine particles using the same.

  The wet dispersion process is a process in which solid particles contained in a slurry are finely pulverized to form a uniform dispersion composed of finer fine particles. For example, it is often performed in a wide range of fields such as printer ink, paint, polymerized toner, color resist, ceramic fine particles, titanium oxide, metal powder, and pharmaceuticals. That is, these are slurries containing inorganic fine particles, organic fine particles, inorganic organic composite fine particles, or a mixture thereof.

  One of the dispersers used for these processes is a media agitation type disperser. This disperser stirs a slurry-like treatment liquid and a medium together in a container, and pulverizes and disperses particles by the shearing force of the medium. The dispersed treatment liquid is separated from the medium by a separator provided in the container and discharged outside the container. As the separator, a sieve type such as a gap type or a screen type is often used.

  The performance of the dispersion treatment is greatly influenced by the diameter of the medium used, and the smaller the diameter of the medium, the smaller the particle diameter in the dispersion. Conventionally, the diameter of a medium that has been widely used is 0.3 mm or more. And the average particle diameter of the dispersion liquid obtained normally is 100 nm (nanometer) or more. It is difficult to obtain fine particles of less than 100 nm, and even if possible, a very long time is required.

  The reason why media of less than 0.3 mm are not used is that there is a problem with the separator. For gap type and screen type separators, it is necessary to make the gap between the sieve meshes 1/3 or less of the media diameter, making it difficult to manufacture the separator, and troubles such as biting and clogging are attached and stable. Therefore, continuous operation cannot be performed.

  However, in recent years, there has been an increasing need for dispersion treatment with a particle size of nanometer order in each field, and media agitation type wet dispersers are also required to further reduce the media diameter to 0.1 mm or less. Yes. When the diameter of the medium is thus reduced, it is no longer possible to use a sieve type such as a gap type or a screen type, and a different type of separator is required.

In addition, another problem has arisen with the reduction in the diameter of media. That is, it is a media packing phenomenon in which the media is pressed to the discharge side by the flow of the slurry. As a result, the force applied to the media on the supply side and the discharge side becomes non-uniform, and an excessive force acts particularly on the discharge side, which tends to cause abnormal wear and unnecessary heat generation. In addition, nano-level dispersion sometimes involves damage to particles and dispersants, and often causes re-aggregation. The media packing phenomenon is more likely to occur in a disperser having a larger crushing chamber length / diameter (hereinafter referred to as L / D ratio).
In common sense so far, a supply port is provided at one end of the tank and a discharge port is provided at the other end. Naturally, this is because there is a concern about a short path, and it has been designed so that the processed material comes into contact with the piston flow in order from the media near the supply port to the media near the discharge port.

  As a disperser that solves the problems related to the separator, a media agitation type wet disperser that separates the media and the processing liquid by centrifugal force has been proposed (Patent Document 1). In other words, the disperser described in Patent Document 1 is for performing dispersion between a vessel having a supply port for supplying a paste to be dispersed and a discharge port for discharging the dispersed paste and an inner wall of the vessel. An outer peripheral surface disposed in the vessel so as to form the annular gap X has a cylindrical rotor, and a flow path is formed from the annular gap X through the rotor to the discharge port. In the middle, a centrifuge for centrifuging the dispersion medium from the dispersion paste is provided, and a circulation opening for sending the centrifuged dispersion medium to the annular gap X is formed in the rotor.

  Since the media agitation type wet disperser described in Patent Document 1 uses a centrifugal separator to separate the media and the processing liquid, it causes troubles such as biting and clogging as in the case of a sieve type. There is no. Therefore, the diameter of the media can be 0.1 mm or less. Further, since the L / D ratio is relatively small, the problem of the media packing phenomenon is solved. However, the place where the pulverization / dispersion treatment is performed is limited to the narrow annular gap X, and the residence time of the treatment liquid is extremely short, and there is a problem that a large volume of treatment is difficult.

  In addition, a media agitation type wet disperser with a further reduced L / D ratio has been proposed (Patent Document 2). That is, the disperser described in Patent Document 2 is provided with a cylindrical separator in a cylindrical pulverization container in a state where the axes are aligned, and the pulverization container is radially divided into two chambers, an inner chamber and an outer chamber. A cylindrical stirring member is rotatably provided in the inner chamber. Although the L / D ratio of the pulverization container is 1.0 or less, since almost the entire inner chamber is used for the pulverization / dispersion process, the residence time of the processing liquid can be slightly increased.

  These media agitation type wet dispersers all have a short L / D ratio and therefore a short residence time. In order to compensate for this, the dispersion force, that is, the agitation force on the media is strengthened. As a result, it was found that inconvenience occurs in the following cases. For example, because the dispersion force is too large, depending on the processed material, it may deteriorate and lose its original characteristics, or once dispersed solid particles may cause re-aggregation, or an extreme increase in viscosity or gelation may occur. There is something. If the dispersion force is weakened to avoid such a problem, the dispersion performance deteriorates because the residence time is short.

In addition, wear resistant materials are used for the walls of the crushing chamber and the stirring rotor, etc. that come into direct contact with the processed material. However, if the dispersion force is increased, wear becomes severe and these materials can be damaged. There is. If the dispersion force is weakened to avoid this problem, the dispersion performance deteriorates because the residence time is short. In any case, the dispersion force is the strongest at the tip of the rotor where the circumferential speed is the fastest. Therefore, reaggregation of particles is considered to occur at the tip of the rotor, and when the peripheral speed of the tip is lowered, the dispersion force at other locations is reduced, leading to deterioration in efficiency. It is done.
JP 2002-306940 A Japanese Patent Laid-Open No. 10-015411

  An object of the present invention is to provide a media agitation type wet disperser used in continuous processing, which can make fine particles in a dispersion liquid in nanometer order. Therefore, the present invention is to provide a media agitation type wet disperser capable of using a medium having a diameter of 0.1 mm or less and capable of reliably separating fine particles from the medium. . Another object of the present invention is to provide a media agitation type wet disperser which eliminates the dwell time shortage due to the reduced L / D ratio, has a strong agitation force and is excellent in pulverization / dispersion function, and does not cause a media packing phenomenon. . It is another object of the present invention to provide a media agitation type wet disperser which does not cause deterioration of a processed product, reaggregation of fine particles, increase in viscosity, gelation, etc. due to excessive dispersion power. Another object of the present invention is to provide a media agitation type wet disperser that does not cause wear on the wall surface of the grinding chamber. Furthermore, it is providing the dispersion | distribution method of the microparticles | fine-particles which can perform the dispersion | distribution process which makes the microparticles | fine-particles in a dispersion liquid nanometer order economically.

In order to solve the above-described problems, a media agitation type wet disperser according to claim 1 of the present invention includes a dispersion tank that includes a lid member at an upper portion and forms a vertical cylindrical crushing chamber therein, and A hollow rotating shaft that is rotatably inserted through the lid member, an upper rotor that is fixed to the rotating shaft and rotates, provided with blades arranged in a cylindrical shape at the top of the crushing chamber, and the crushing A lower rotor which is provided at a lower portion of the chamber and arranged in a cylindrical shape and which is fixed to the rotary shaft and rotates; and a blade which is arranged inside the upper rotor and arranged in a cylindrical shape at the rotary shaft An inner rotor that is fixed and rotated, a processing liquid supply port is provided at an upper portion of the crushing chamber, and a hollow portion of the rotating shaft is communicated with the inner rotor to form a processing liquid discharge port. a media-agitation type wet dispersing machine to be, The upper rotor includes a cylindrical portion including the blade and a substantially disc-shaped holding portion that fixes the cylindrical portion to the rotating shaft, and the cylindrical portion is located on a lower surface of the holding portion, An upper circulation flow that flows from the inner side to the outer side and flows from the outer side to the inner side below the cylindrical portion is formed, and the lower rotor includes the cylindrical portion that includes the blade and the cylindrical shape A substantially disc-shaped holding part that fixes the part to the rotating shaft, and the cylindrical part is located on the upper surface of the holding part, so that the cylindrical part flows from the inside to the outside and the cylindrical shape A lower circulation flow that flows from the outside to the inside is formed above the section, and means for uniformly mixing the grinding chamber with the upper circulation flow and the lower circulation flow is employed.

Further, the media agitation type wet disperser according to claim 2 of the present invention is the media agitation type wet disperser according to claim 1, wherein when the diameter of the grinding chamber is D and the upper and lower lengths are L, A means having the relationship of Formula 1 is adopted.
0.5 <L / D <1.5 ... Formula 1

A media agitation type wet disperser according to claim 3 of the present invention is the media agitation type wet disperser according to claim 1 or 2 , wherein the length of the cylindrical portion of the upper rotor is La. , Means having a relationship of Formula 2 between the length L and the length L is adopted.
0.3L <La <0.6L ... Formula 2

The media agitation type wet disperser according to claim 4 of the present invention, in the media-agitation type wet disperser according to any one of claims 1 to 3, the length of the tubular portion of the lower rotor When Lb is Lb, means having the relationship of Formula 3 with the length L is adopted.
0.3L <Lb <0.6L ... Formula 3

The media agitation type wet disperser according to claim 5 of the present invention, in the media-agitation type wet disperser according to any one of claims 1 to 4, wherein the blades of the lower rotor, a convex cross section And adopts means in which the protrusions are arranged facing outward.

The media agitation type wet disperser according to Claim 6 of the present invention, in the media-agitation type wet disperser according to any one of claims 1 to 5, wherein the holding portion of the lower rotor, the opening Uses the means provided.

The media agitation type wet disperser according to claim 7 of the present invention, in the media-agitation type wet disperser according to any one of claims 1 to 6, wherein the holding portion of the lower rotor, said milling A means having an impeller for stirring the bottom surface of the chamber is employed.

The media agitation type wet disperser according to claim 8 of the present invention, the boundary portion of the media-agitation type wet disperser according to any one of claims 1 to 7, the sides and bottom of the grinding chamber However, a section having a radius of curvature R is employed, and means having the relationship of Formula 4 with respect to the diameter D is employed.
D / 30 <R <D / 3 ...... Formula 4

The media agitation type wet disperser according to claim 9 of the present invention is the media-agitation type wet disperser according to any one of claims 1 to 8, wherein the dispersion tank, cooling jacket on the outside The means equipped with is adopted.

Since the media agitation type wet disperser of the present invention is configured as described above, the inner rotor has a function of separating the media and the processing liquid and a function of classifying fine particles by forming a centrifugal separator. . Further, the upper rotor has a function of pulverizing and dispersing solid particles by forming a circulating flow (upper circulating flow) in which the media and the processing liquid flow inside and outside. Further, the lower rotor has a function of forming a circulating flow (lower circulating flow) through which the media and the processing liquid flow, and crushing and dispersing solid particles, and a function of retaining and mixing a large amount of the processing liquid. Is provided.
That is, the media agitation type wet disperser of the present invention is provided with a processing liquid supply port and a discharge port at the upper part of the grinding chamber. It is a concept that realizes a completely uniform mixing state with a circulation amount that can ignore a short path by generating a circulating flow, and is an epoch-making invention that overturns conventional common sense.

  Therefore, the media agitation type wet disperser of the present invention can use media having a diameter of 0.1 mm or less, and the fine particles in the dispersion can be in the nanometer order. In addition, an excellent crushing / dispersing function can be exhibited without causing a media packing phenomenon. In addition, it is possible to perform a good dispersion treatment without causing deterioration of the treated product, reaggregation of fine particles, increase in viscosity, gelation and the like. Furthermore, it can process without causing abrasion on the wall surface of the grinding chamber. Furthermore, scale-up to a large-capacity large machine can be performed without problems. As a result of the above, it is possible to provide a fine particle dispersion method in which the dispersion treatment with a particle size of nanometer order is economically performed with stable continuous operation.

Hereinafter, embodiments of the present invention shown in the drawings will be described.
1 and 2 show an embodiment of a media agitation type wet disperser according to the present invention. FIG. 1 is a schematic cross-sectional view of a media agitation type wet disperser, and FIG. 2 is a schematic cross-sectional view taken along line AA shown in FIG. This media agitation type wet disperser 1 includes a dispersion tank 2 having a lid member 22 at the top and forming a vertical cylindrical crushing chamber 20 therein, and a hollow rotation provided rotatably through the lid member 22. A shaft 3, an upper rotor 4 that is fixed to the rotating shaft 3 and rotates with a blade arranged in a cylindrical shape located above the grinding chamber 20, and a cylindrical shape located at the lower part of the grinding chamber 20. A lower rotor 6 which is fixed to the rotary shaft 3 and rotates, and an inner rotor 5 which is fixed to the rotary shaft 3 and is provided with blades arranged inside the upper rotor 4 and arranged in a cylindrical shape. It is configured.

  The crushing chamber 20 formed inside the dispersion tank 2 has an L / D ratio in a range of 0.5 <L / D <1.5, where D is the diameter and L is the upper and lower length. It is preferable. When L / D is smaller than 0.5, the residence time is shortened and sufficient capacity cannot be exhibited. Further, when L / D is larger than 1.5, the media packing phenomenon is likely to occur, which is not preferable.

  Moreover, it is preferable that the boundary part of the side surface and bottom face of the grinding | pulverization chamber 20 makes the cross-sectional curve shape of the radius R, and the relationship between the radius R and the diameter D is the range of D / 30 <R <D / 3. It is preferable. When the radius R is smaller than D / 30, the movement of the medium and the processing liquid becomes dull, and the media packing phenomenon is likely to occur from that point. Moreover, when R is larger than D / 3, it is difficult to attach and utilize the lower rotor 6.

  A lid member 22 is attached to the upper end of the dispersion tank 2 via a flange 21 so as to be substantially closed. The treatment liquid supply port 23 provided in the dispersion tank 2 is preferably provided in the lid member 22 as shown in FIG.

  A pipe-shaped rotating shaft 3 is rotatably provided in the lid member 22 through its axis. A shaft seal 34 is interposed between the outer peripheral surface of the rotating shaft 3 and the inner peripheral surface of the lid member 22 so that the grinding chamber 20 can be sealed. The rotary shaft 3 is in the form of a pipe having a hollow portion 31 formed in the center thereof, and the upper rotor 4, the inner rotor 5 and the lower rotor 6 are attached to one end of the rotary shaft 3 located in the crushing chamber 20. ing. Moreover, the other end of the rotating shaft 3 is located outside the dispersion tank 2, and a drive device is attached (not shown).

  The upper rotor 4 includes a cylindrical portion 42 including a plurality of blades 43 arranged in a cylindrical shape at regular intervals on the lower surface of a disk-shaped holding portion 41 fixed to the rotary shaft 3 by a key or the like. . When the upper rotor 4 rotates in the direction of the arrow in FIG. 2, a centrifugal force is generated by the blade 43, and the media and the processing liquid are discharged from the inside to the outside through the opening 44 formed between the blades 43. The

  As a result, as shown in FIG. 3, an upper circulation flow F <b> 1 in which the medium and the processing liquid circulate around the upper rotor 4 is formed. That is, the upper circulating flow F1 flows from the inner side to the outer side at the opening 44, flows from the upper side to the lower side at the outer side of the cylindrical part 42, and flows from the outer side to the inner side at the opened lower end. Inside the portion 42, the circulation flow flows from the lower side toward the upper side.

  A large shearing force is generated between the wall surface of the crushing chamber 20 and the blade 43 outside the cylindrical portion 42, and the processing liquid is subjected to crushing and dispersion processing. Further, since the upper circulating flow F1 is formed in the upper part of the pulverizing chamber 20, the medium and the processing liquid are agitated to be in a uniform mixed state, so that no media packing phenomenon occurs. In order to effectively form the upper circulation flow F1, the length La of the cylindrical portion 42 may have a relationship of 0.3L <La <0.6L with respect to the length L of the crushing chamber 20. preferable.

  The inner rotor 5 is located inside the upper rotor 4, and includes a cylindrical portion 52 composed of a plurality of blades 53 arranged in a cylindrical shape at regular intervals on the upper surface of the disc-shaped holding portion 51. And the open upper surface of the cylindrical part 52 is being fixed to the rotating shaft 3 with the volt | bolt etc. (not shown) in the state which was closely_contact | adhered to the lower surface of the holding | maintenance part 41 of the upper rotor 4. FIG.

  The outer peripheral surface of the cylindrical portion 52 is located a little away from the inner peripheral surface of the cylindrical portion 42 of the upper rotor 4, and the gap serves as the flow path of the upper circulating flow F <b> 1 as described above, and goes from the lower side to the upper side. A flow is formed. Further, the inner peripheral surface of the cylindrical portion 52 is located slightly away from the outer surface of the rotating shaft 3, and a space portion 56 is formed inside the cylindrical portion 52. The rotation shaft 3 is provided with an opening 32 at the position of the space portion 56, and the hollow portion 31 of the rotation shaft 3 communicates with the space portion 56. As a result, the hollow portion 31 forms a dispersion outlet 33. That is, the dispersion liquid subjected to the pulverization / dispersion process in the upper circulation flow F <b> 1 flows into the space portion 56 through the opening 54 between the blades 53, and is discharged from the discharge port 33 through the opening 32.

  When the inner rotor 5 rotates in the direction of the arrow shown in FIG. Therefore, the separation function and the classification function are exhibited with respect to the particles passing through the opening 54. That is, the medium and the particles having a large particle diameter cannot flow into the space portion 56, and only the fine particles are discharged through the space portion 56. Media and large particles that could not flow into the space 56 are immediately returned to the upper circulating flow F1. Then, since the pulverization / dispersion process is performed again, the dispersion process and the classification process are surely performed.

  The flow rate of the processing liquid passing through the opening 54 of the cylindrical portion 52 is smaller than the flow rate of the upper circulation flow F1. Therefore, the cylindrical portion 52 of the inner rotor 5 can be made slightly shorter than the cylindrical portion 42 of the upper rotor 4. That is, it is preferable that the length Lc of the cylindrical part 52 is shorter than the length La of the cylindrical part 42 and has a relationship of 0.5La <Lc <0.8La.

  On the inner peripheral surface of the cylindrical portion 42, the upper circulation flow F1 forms a flow from the lower side toward the upper side. Therefore, when Lc is shorter than La, the blade 43 is positioned on the upstream side of the circulating flow, and the blade 53 is positioned on the downstream side of the circulating flow. Therefore, after the upstream blade 43 separates large particles in advance, the downstream blade 53 performs final separation / classification, and efficient processing can be performed.

  The lower rotor 6 is located at the lower part of the crushing chamber 20 and is formed from a plurality of blades 63 arranged in a cylindrical shape at regular intervals on the upper surface of a disc-shaped holding part 61 fixed to the rotary shaft 3 by bolts or the like. A cylindrical portion 62 is provided. When the lower rotor 6 rotates in the direction of the arrow in FIG. 2, a centrifugal force is generated by the blade 63, and the media and the processing liquid are discharged from the inside to the outside through the opening 64 formed between the blades 63. Is done.

  As a result, as shown in FIG. 3, a lower circulation flow F <b> 2 in which the medium and the processing liquid circulate around the lower rotor 6 is formed. That is, the lower circulating flow F2 flows from the inner side to the outer side at the opening 64, flows from the lower side to the upper side at the outer side of the cylindrical part 62, and flows from the outer side to the inner side at the opened upper end. Inside the portion 62, the circulating flow flows from the upper side to the lower side.

  And outside the cylindrical part 62, a big shearing force generate | occur | produces between the wall surface of the crushing chamber 20, and the braid | blade 63, and a process liquid will receive a grinding | pulverization and dispersion | distribution process. Further, in the lower part of the pulverizing chamber 20, since the lower circulation flow F2 is formed, the media and the processing liquid are agitated to be in a uniform mixed state, so that no media packing phenomenon occurs. In order to effectively form the lower circulation flow F2, the length Lb of the cylindrical portion 62 may have a relationship of 0.3L <Lb <0.6L with respect to the length L of the crushing chamber 20. preferable.

  Furthermore, it is preferable that the upper circulation flow F1 formed in the upper part of the crushing chamber 20 and the lower circulation flow F2 formed in the lower part of the crushing chamber 20 are well mixed with each other. By forming such a flow, the processed material in the entire pulverization chamber 20 is uniformly held, and a large-capacity disperser that does not cause a media packing phenomenon can be obtained.

  The blade 63 of the lower rotor 6 preferably has a shape that generates a strong centrifugal force, and preferably has a shape that gives a strong shearing force to the media. For this reason, as shown in FIG. 2, it is preferable that the blade 63 has a convex cross-section, and it is preferable to arrange the protrusions outward.

  The holding portion 61 of the lower rotor 6 is preferably provided with a plurality of openings 66 and is preferably provided with an impeller (not shown) for stirring the bottom surface of the crushing chamber 20. As a result, the circulation of the media and the processed material at the bottom of the crushing chamber 20 becomes active, and the lower circulation flow F2 can be further strengthened.

  The media agitation type wet disperser of the present invention can further include one or more intermediate rotors 8 between the upper rotor 4 and the lower rotor 6. That is, in the example shown in FIG. 4A, the upper and lower surfaces of the disc-shaped holding portion 81 in which the intermediate rotor 8 is positioned between the upper rotor 4 and the lower rotor 6 and is fixed to the rotating shaft 3 by bolts or the like. In addition, a cylindrical portion 82 composed of a plurality of blades arranged in a cylindrical shape at regular intervals is provided.

  As a result, an intermediate circulation flow F3 that newly reinforces the upper circulation flow F1 is generated above the intermediate rotor 8, and an intermediate circulation flow F4 that reinforces the lower circulation flow F2 is generated below the intermediate rotor 8. . Therefore, the intermediate rotor 8 further ensures the circulation flow of the media and the processed material in the grinding chamber 20, and is effective particularly when the L / D ratio is increased.

  In the example shown in FIG. 4B, the intermediate rotor 8 is located between the upper rotor 4 and the lower rotor 6, and on the upper surface of the disc-shaped holding portion 81 fixed to the rotary shaft 3 by a bolt or the like. A cylindrical portion 82 composed of a plurality of blades arranged in a cylindrical shape at regular intervals is provided. As a result, a new intermediate circulation flow F5 is generated in the upper portion of the intermediate rotor 8 in addition to the upper circulation flow F1 and the lower circulation flow F2. Therefore, the intermediate rotor 8 is effective when the circulation flow of the media and the processed material in the grinding chamber 20 is further enhanced, and particularly when the L / D ratio is increased.

  Thus, by providing the intermediate rotor 8, the L / D ratio of the crushing chamber 20 can be increased. When the number of intermediate rotors 8 is N, the L / D ratio is preferably set to a value in a range larger than 0.3 (N + 2) and smaller than 0.75 (N + 2).

  The members that are in direct contact with the processed material such as the dispersion tank 2, the upper rotor 4, the inner rotor 5, and the lower rotor 6 are preferably made of a wear-resistant material, and ceramics such as alumina, alumina zirconia, and silicon carbide are preferably used. It is preferable to use it. Thereby, it can prevent that an impurity mixes in a product.

  The media stirring type wet disperser 1 of the present invention can perform a powerful stirring operation in a relatively narrow crushing chamber 20. Therefore, it is preferable to provide a cooling jacket outside the dispersion tank 2 to forcibly cool the crushing chamber 20. The jacket allows temperature management of the processed material, and can also be used for heating at the beginning of the processing.

  The fine particle dispersion method of the present invention is a dispersion method of a slurry-like treatment liquid containing polymer fine toner, color resist, printer ink, ceramic powder, inorganic fine particles such as titanium oxide, organic fine particles, inorganic organic composite fine particles, or a mixture thereof. The media stirring type wet disperser 1 of the present invention is used.

  In addition, as shown in FIG. 5, the fine particle dispersion method of the present invention uses the media stirring type wet disperser 1 of the present invention, the holding tank 9 and the pump 10, and the treatment liquid stored in the holding tank 9 is used. The pump is supplied to the media agitation type wet disperser 1 by the pump 10, and the processing liquid discharged from the media agitation type wet disperser 1 is returned to the holding tank 9 to perform circulation processing.

  As described above, it is usually necessary to cool the treatment liquid in the fine particle dispersion treatment. The treatment liquid can be cooled by flowing cooling water through a jacket provided in the media stirring type wet disperser 1. However, in the distributed processing in which the circulation processing is performed, the holding tank 9 may be provided with a cooling jacket. Moreover, in the circulation process shown in FIG. 5, it can cool by providing a separate cooler in the flow path of a processed material. Alternatively, these methods can be combined. And the temperature of a process liquid can be adjusted to 10 to 80 degreeC by providing a temperature control system.

  The fine particle dispersion method of the present invention enables a dispersion having a fine particle diameter of nanometer order of the dispersion liquid. For this reason, the diameter of the media used in the media stirring type wet disperser 1 is 0.015 to 0. .3 mm is preferable. When using a media of 0.3 mm or more, care must be taken so that the gap between the inner rotor 5 and the upper rotor 4 is sufficiently large. Also, the use of media of 0.015 mm or less may result in an insufficient separation function.

  The filling rate of the media is preferably 30 to 75% with respect to the actual capacity of the grinding chamber 20. Here, the actual capacity of the grinding chamber 20 is a volume obtained by subtracting the volumes of the rotors 4, 5, 6, etc. from the volume of the grinding chamber 20. When the filling rate is 75% or more, the possibility of the medium flowing out during operation increases. Moreover, when the filling rate is 30% or less, the pulverization / dispersion efficiency is lowered, which is not preferable.

  In the fine particle dispersion method of the present invention, the outer peripheral speed of the upper rotor 4 or the lower rotor 6 is preferably 3 to 20 m / second, more preferably 3 to 18 m / second. Depending on the material to be treated, sufficient media movement is often not obtained at a speed of 3 m / sec or less. Further, when the speed is set to 20 m / second or more, there is a possibility that problems such as remarkable wear, heat generation, and re-aggregation due to excessive force may occur.

  The fine particle dispersion method of the present invention is a continuous type, and usually a holding tank 9 and a pump 10 are provided to perform a circulation treatment. And although the average residence time of the process liquid in the grinding | pulverization chamber 20 of the media stirring type wet disperser 1 changes with process substances, generally it is preferable to set it as the range of 0.5 to 10 second. Here, the average residence time is a value obtained by dividing the retention amount of the treatment liquid in the crushing chamber 20 by the circulation flow rate of the treatment liquid. Further, the total residence time of the system is generally in the range of 30 seconds to 30 minutes. Therefore, the number of passes through the media agitation type wet disperser 1 can be set from the average residence time of the grinding chamber 20 and the total residence time of the system. Further, the processing time can be set from the total amount of the processing liquid, the circulation flow rate, and the number of passes.

Using the media stirring type wet disperser of the present invention shown in the embodiment, a test was conducted to disperse the secondary agglomerated titanium oxide under the following conditions, and the performance was confirmed.
Put the prepared slurry in the holding tank, introduce it into the supply port of the disperser with a metering pump, form a circulation system that returns the slurry discharged from the discharge port of the disperser to the holding tank again, and start the disperser in this state And tested.
After starting the disperser, samples were taken from the discharge port of the disperser every predetermined time. The particle size was measured by a dynamic light scattering method using Microtrack UPA manufactured by Nikkiso Co., Ltd.

Disperser: Disperser shown in FIGS. 1 and 2
Dispersion tank: inner diameter 130 mm, L / D ratio = 1.0
Outer rotor outer diameter: 120mm
Rotation speed: 1600rpm (10m / s)
Media: Material: Zirconia
Diameter: 0.03mm
Filling rate: 65%
Processed product: Titanium oxide MT-150W (Taika)
Primary particle size: 15nm
Secondary aggregate diameter: 2.3 μm
Usage: 300g
Solvent: Water, 2700 g
Concentration: 10wt%
Dispersant: Nop Cosperth 44-c, 7g
Processing flow rate: 1 liter / min

(Comparative Example 1)
A conventional disperser (L / D ratio = 0.5) shown in FIG. 6A was used, and other conditions were tested in the same manner as in the example.

(Comparative Example 2)
A conventional disperser (L / D ratio = 1.0) shown in FIG. 6B was used, and other conditions were tested in the same manner as in the example.

  For the tests of Examples, Comparative Examples 1 and 2, the change in average particle size with respect to the treatment time is shown in FIG. In the examples, the average particle diameter can be reduced to 30 nm in 20 minutes from the start of the treatment, and the average particle diameter can be reduced to 20 nm. On the other hand, in Comparative Example 1, in order to set the average particle size to 30 nm, a treatment time twice or more was required, and the average particle size could not be set to 20 nm. Further, in Comparative Example 2, it was found that reaggregation occurred during the treatment, and the average particle diameter gradually increased.

  As a result, the media agitation type wet disperser of the present invention can form a plurality of circulation flows in the pulverization chamber to uniformly hold a large amount of processing liquid, and uses media having a diameter of 0.1 mm or less. Thus, it was confirmed that it was possible to disperse the fine particles in the treatment liquid to the nanometer order.

It is a schematic sectional drawing which shows an example of implementation of the media stirring type wet disperser of this invention. It is the schematic sectional drawing seen along the AA line shown in FIG. FIG. 2 is an explanatory diagram showing a circulating flow formed in the media agitation type wet disperser shown in FIG. 1. It is explanatory drawing which shows the circulating flow formed in the media stirring type wet disperser of this invention provided with the intermediate rotor. It is a schematic block diagram in the case of performing a circulation process. It is a schematic sectional drawing which shows the conventional media stirring type wet disperser used by the comparative example. It is a graph which shows the particle size distribution of the dispersion liquid obtained by the Example and the comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Media stirring type wet disperser 2 Dispersion tank 3 Rotating shaft 4 Upper rotor 5 Inner rotor 6 Lower rotor 8 Intermediate rotor 9 Holding tank 10 Pump 20 Grinding chamber 21 Flange 22 Lid member 23 Supply port 31 Hollow part 32 Opening 33 Discharge port 34 Shaft seal 41 Holding part 42 Tubular part 43 Blade 44 Opening 51 Holding part 52 Tubular part 53 Blade 54 Opening 56 Space part 61 Holding part 62 Cylindrical part 63 Blade 64 Opening 66 Opening 81 Holding part 82 Cylindrical part

Claims (9)

A dispersion tank having a lid member at the top and forming a vertical cylindrical grinding chamber inside;
A hollow rotation shaft that is rotatably inserted through the lid member;
An upper rotor that is fixed to the rotary shaft and rotates, provided with blades arranged in a cylindrical shape at the upper part of the crushing chamber;
A lower rotor which is fixed to the rotating shaft and rotates, provided with blades arranged in a cylindrical shape at the lower part of the grinding chamber;
An inner rotor that is fixed to the rotating shaft and rotates, provided with blades arranged inside the upper rotor and arranged in a cylindrical shape;
A media agitation type wet disperser provided with a treatment liquid supply port at the top of the crushing chamber, and having a hollow portion of the rotating shaft communicated with the inside of the inner rotor to serve as a treatment liquid discharge port ,
The upper rotor includes a cylindrical portion including the blade and a substantially disc-shaped holding portion that fixes the cylindrical portion to the rotation shaft, and the cylindrical portion is located on a lower surface of the holding portion, Forming an upper circulation flow that flows from the inside to the outside and flows from the outside to the inside below the tubular portion;
The lower rotor includes a cylindrical portion including the blade and a substantially disc-shaped holding portion that fixes the cylindrical portion to the rotating shaft, and the cylindrical portion is positioned on an upper surface of the holding portion. Forming a lower circulation flow that flows from the inside to the outside and flows from the outside to the inside above the tubular portion;
The media stirring type wet disperser characterized in that the pulverization chamber is uniformly mixed by the upper circulating flow and the lower circulating flow . 2. The media stirring type wet disperser according to claim 1, wherein when the diameter of the crushing chamber is D and the upper and lower lengths are L, the relationship of Formula 1 is satisfied.
0.5 <L / D <1.5 ... Formula 1 3. The media agitation type wet dispersion according to claim 1 , wherein when the length of the cylindrical portion of the upper rotor is La, there is a relationship of Formula 2 with the length L. 4. Machine.
0.3L <La <0.6L ... Formula 2 When the length of the tubular portion of the lower rotor and Lb, between the length L, a according to any one of claims 1 to 3, characterized in that a relationship of the formula 3 Media agitation type wet disperser.
0.3L <Lb <0.6L ... Formula 3 Wherein the blade lower rotor is a convex cross section of the blade, projections and media-agitation type wet disperser according to any one of claims 1 to 4, characterized in that it is arranged outward Machine. Wherein the holding portion of the lower rotor, media-agitation type wet disperser according to any one of claims 1 to 5, characterized in that it comprises an opening. Wherein the holding portion of the lower rotor, media-agitation type wet disperser according to any one of claims 1 to 6, characterized in that it comprises an impeller for agitating the bottom of the grinding chamber. Boundary between the side surface and the bottom surface of the pulverizing chamber, forms a cross section curved with a radius R, between the diameter D, any one of claims 1 to 7, characterized in that the relationship of Equation 4 1 The media agitation type wet disperser according to item .
D / 30 <R <D / 3 ...... Formula 4 The dispersion tank, media-agitation type wet disperser according to any one of claims 1 to 8, characterized in that it comprises a cooling jacket on the outside thereof.

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