JP2006247557A - Media agitation type wet disperser - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a media agitation type wet disperser which is capable of conducting the dispersion by nanometer order and is excellent in classification performance with large scale. <P>SOLUTION: The media agitation type wet disperser is provided with a cylindrical dispersion tank 2, a hollow rotation shaft 3, an outer rotor 4 which is equipped with a plurality of blades tubularly arranged and which generates centrifugal force and, an inner rotor 5 positioned at the inner side of the outer rotor 4 which is equipped with blades tubularly arranged and which generates centrifugal force. The material to be treated forms circulation flow to circulate the inside and outside of the outer rotor 4 and is acted by the dispersing function and the classification function in harmonization. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a media agitation type wet disperser, and more particularly, to a media agitation type wet disperser capable of obtaining a dispersion composed of nanometer order fine particles by continuous dispersion treatment.

The dispersion of fine particles is often performed in a wide range of fields such as inks, paints, ceramic fine particles, metals, inorganic substances, and pharmaceuticals. One of the dispersers used for these treatments is a media agitation type wet pulverizer. This pulverizer agitates the treatment liquid and the media together by an agitating member provided in the pulverization vessel, and the shearing force of the media The particles are pulverized and dispersed.
The dispersed treatment liquid is separated from the medium by a separator provided in the pulverization container, and then discharged out of the container. As the separator, a sieve type such as a gap type or a screen type is often used.

  In such a dispersion treatment, the particle diameter after the treatment is almost proportional to the media diameter, and therefore it is necessary to use a medium having a small diameter in order to obtain a fine particle dispersion. Conventionally, media having a diameter of 0.3 mm or more are often used as media, but the average particle diameter after treatment usually obtained is 100 nm (nanometers) or more. Fine particles of less than 100 nm are difficult to prepare, and even if prepared, it takes a very long time.

  Therefore, a method of obtaining a dispersion liquid having an average particle diameter of less than 100 nm by using a medium having a diameter of 0.2 mm or less in a media agitation type wet disperser has been studied. For example, Patent Document 1 describes a method for producing a dispersion liquid in which a medium is made of ceramics, hard glass, hard plastic, metal, or a metal compound, and uses fine beads having a diameter of 0.2 mm or less.

  However, when the diameter of the media is reduced, a separator that separates the dispersion from the media becomes a problem. In the conventional sieve type such as the gap type and the screen type, it is necessary to make the gap of the sieve mesh 1/3 or less of the media diameter, making it difficult to manufacture the separator, and biting, clogging, etc. With this trouble, stable continuous operation cannot be performed.

  Recently, in each field, there is an increasing need for dispersion treatment with a particle size of nanometer order, and media agitation type wet dispersers are required to further reduce the media diameter to 0.1 mm or less. Yes. However, when the diameter of the medium becomes small in this way, 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.

As a separator that solves such a problem, a centrifugal separator that separates media and dispersion liquid by centrifugal force has been proposed (for example, Patent Document 2). In this centrifugal separator, two discs are provided on a rotating shaft at regular intervals, and a plurality of blades are arranged in a cylindrical shape between both discs. However, in this pulverizer, the stirring member for pulverization also serves as the rotating member for separation, so it is difficult to adjust the balance between the pulverization function and the classification function, and both performances can be fully exhibited. The problem that is difficult is left.
JP-A-11-33377 JP 2003-144950 A

  An object of the present invention is to improve the performance of a continuous media agitation type wet disperser. By using a media having a diameter of 0.1 mm or less, a nanometer order dispersion treatment can be performed in a large capacity. Another object is to provide a disperser in which separation of media is sure, particle classification performance is excellent, and stable and continuous operation is possible.

  In order to solve the above-described problems, a media agitation type wet disperser according to claim 1 of the present invention includes a cylindrical dispersion tank whose one end is closed and the other end side of the dispersion tank. A hollow rotary shaft provided rotatably, an outer rotor having a plurality of blades arranged in a cylindrical shape and generating centrifugal force by being fixed to the rotary shaft and rotating, and located inside the outer rotor A plurality of blades arranged in a cylindrical shape and having an inner rotor that generates centrifugal force by rotating while being fixed to the rotating shaft, and the dispersion tank includes a supply port that communicates the inside and outside of the dispersion tank The hollow shaft has a hollow portion that communicates with the inside of the inner rotor to form a discharge port.

  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 the plurality of blades of the outer rotor are more than the plurality of blades of the inner rotor. A means provided near the one end of the dispersion tank is employed.

  Furthermore, the 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 supply port is provided at the other end of the dispersion tank. Adopting means.

  Further, the media agitation type wet disperser according to claim 4 of the present invention is the media agitation type wet disperser according to any one of claims 1 to 3, wherein the dispersion tank includes a cooling jacket outside thereof. Adopting means.

  According to the present invention, the outer rotor has a function of pulverizing and dispersing the processed material, and the inner rotor has a function of separating media and a function of classifying fine particles. The processed material forms a circulating flow that circulates inside and outside the outer rotor together with the media, and is pulverized and dispersed in this circulation process. Further, the processed material is classified by the inner rotor, and the fine particle dispersion is discharged through the inner rotor, and the medium and the large particles are returned to the circulation flow again.

  As a result, in the disperser of the present invention, the grinding / dispersing function of the outer rotor and the separating / classifying function of the inner rotor act in harmony, and the nanometer uses a medium having a diameter of 0.1 mm or less. It is possible to perform distributed processing of meter order with a large capacity. In addition, stable continuous operation can be performed.

Hereinafter, embodiments of the present invention shown in the drawings will be described.
FIG. 1 and FIG. 2 show an embodiment of a media agitation type wet disperser according to the present invention. FIG. 1 is a schematic sectional view of the media agitation type wet disperser, and FIG. -A schematic cross-sectional view taken along line A. The media agitation type wet disperser 1 includes a dispersion tank 2, a rotating shaft 3, an outer rotor 4, an inner rotor 5, and the like.

  The dispersion tank 2 is a cylindrical container with one end closed, and a lid member 22 is attached to the other end via a flange 21 so that the other end is substantially closed. Further, the attachment position of the supply port 23 provided in the dispersion tank 2 is preferably in the vicinity of the other end of the dispersion tank 2 in view of the positional relationship with the circulation flow and the discharge port described later. It is particularly preferable to provide it.

  The lid member 22 is formed in a substantially cylindrical shape having a hollow inside, and a hollow rotary shaft 3 is rotatably provided at the axial center of the hollow portion. 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 pulverization tank 2 can be sealed.

  The rotary shaft 3 has a hollow portion 31 formed at the center thereof, and is provided coaxially with the other end of the dispersion tank 2 inserted therethrough. In the dispersion tank 2, an outer rotor 4 and an inner rotor 5 are attached to one end of the rotating shaft 3. 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 outer rotor 4 includes a plurality of blades 43 arranged in a cylindrical shape at regular intervals on one surface of a disk-shaped holding portion 41. The open end of the cylindrical portion 42 is located on one end side of the dispersion tank 2, and the other end closed by the holding portion 41 is attached to the rotary shaft 3 by the key 45 on the other end side of the dispersion tank 2. ing.

  Therefore, when the outer rotor 4 is rotated in the direction of the arrow in the figure, a centrifugal force is generated by the blade 43, and the processed material flows from the inside toward the outside through the opening 44 between the blades 43. As a result, the processed material and media in the dispersion tank 2 flow from the other end side toward the one end side outside the blade 43, flow from the outside toward the inside at the opened end, and one end side inside the blade 43. Thus, a circulating flow that flows toward the other end side is formed.

  Further, due to the rotation of the outer rotor 4, the processed material in the dispersion tank 2 is agitated together with the medium, and is subjected to pulverization / dispersion treatment by a shearing force generated between the inner wall of the dispersion tank 2 and the blade 43. At the same time, the processed product circulates in and out of the outer rotor 4 so that the whole is well stirred and the entire processed product is processed uniformly.

  The inner rotor 5 includes a plurality of blades 53 that are positioned inside the outer rotor 4 and arranged in a cylindrical shape at regular intervals on one surface of a disk-shaped holding portion 51. The cylindrical portion 52 is fixed to the rotary shaft 3 by a bolt 55 in a state where the open end of the cylindrical portion 52 is in close contact with one surface of the holding portion 41 of the outer rotor 4.

  The outer peripheral surface of the blade 53 is located slightly away from the inner peripheral surface of the blade 43 of the outer rotor 4. The gap between the outer peripheral surface of the blade 53 and the inner peripheral surface of the blade 43 serves as a circulation flow path formed inside and outside the outer rotor 4 and flows from one end side to the other end side of the dispersion tank 2. Is formed.

Further, the inner peripheral surface of the blade 53 is located slightly away from the outer surface of the rotating shaft 3, and a space portion 56 is formed inside the blade 53. An opening 32 is provided in the rotary shaft 3 located in the space portion 56, and the discharge port 33 is formed when the hollow portion 31 of the rotary shaft 3 communicates with the space portion 56.
Therefore, the processed material flowing in from the supply port 23 finally flows into the space 56 via the opening 54 between the blades 53 and is discharged from the discharge port 33.

  As in the case of the outer rotor 4, the inner rotor 5 generates a centrifugal force by the blade 53 when it rotates in the direction of the arrow shown in the figure. Therefore, the separation function and the classification function are exhibited with respect to the particles passing through the opening 54. That is, particles and media having a large particle size cannot flow into the space portion 56, and only fine particles are discharged through the space portion 56.

  Also, the large particles and media that could not flow into the space 56 are immediately returned to the circulating flow formed inside and outside the outer rotor 4 and are crushed and dispersed again. In addition, the classification process is surely performed.

  Since the inner rotor 5 is located inside the outer rotor 4, the blade 53 and the blade 43 are substantially in the same position with respect to the axial direction. Thereby, large particles separated by the inner rotor 5 can be quickly returned to the circulation flow of the outer rotor 4.

  The blade 43 is preferably provided at a position closer to one end of the dispersion tank than the blade 53. A gap between the outer peripheral surface of the blade 53 and the inner peripheral surface of the blade 43 is a circulation flow path, and flows from one end side to the other end side of the dispersion tank 2. Therefore, since the blade 43 is positioned on the upstream side of the blade 53, after the blade 43 previously separates large particles, the blade 53 performs final separation / classification.

  Members that are in direct contact with the processed material such as the dispersion tank 2, the outer rotor 4, and the inner rotor 5 are preferably made of a wear-resistant material, and ceramics such as alumina, alumina zirconia, and silicon carbide are preferably used. . Thereby, it can prevent that an impurity mixes in a product.

  The media agitation type wet disperser 1 of the present invention can perform a powerful agitation operation in a relatively narrow dispersion tank 2. Therefore, it is preferable to cool the dispersion tank 2 forcibly, and it is preferable to provide a cooling jacket 6 outside the dispersion tank 2 as shown in the figure. The cooling jacket 6 covers the entire dispersion tank 2 as much as possible, and is provided with a water supply port 61 and a drain port 62 so as not to drift. The jacket 6 makes it possible to control the temperature of the processed material, and can also be used for heating at the beginning of the processing.

Using the media stirring type wet disperser of the present invention, 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 crusher 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 diameter was measured by a laser diffraction and light scattering method using a microtrack MKIIDRA manufactured by Nikkiso Co., Ltd.

Processing condition disperser: Disperser shown in FIGS. 1 and 2, outer diameter of outer rotor 120 mm
Motor: 3.7kw, maximum rotation speed 3600rpm
Media: Zirconia, diameter 0.03mm
Usage 0.84kg
Processed product: Titanium oxide MT-150W (Taika)
Primary particle diameter 15 nm, secondary aggregate diameter 2.3 μm
Processed amount: 300g
Solvent: Amount of water solvent: 2700 g
Concentration: 10wt%
Dispersant: Nop Cosperth 44-c, 7g
Processing volume: 1 liter / min

  The rotors were operated at a rotational speed of 2070 rpm, and a dispersion liquid having an average particle diameter of 35.8 nm was obtained 90 minutes after the start of the operation. No media was found in the dispersion.

  The rotational speed of both rotors was changed to 1600 rpm, and the other conditions were operated in the same manner as in Example 1. 90 minutes after the start of operation, a dispersion having an average particle diameter of 24.1 nm was obtained. No media was found in the dispersion.

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.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Media stirring type wet disperser 2 Dispersion tank 3 Rotating shaft 4 Outer rotor 5 Inner rotor 6 Jacket 7 Media 21 Flange 22 Lid member 23 Supply port 31 Hollow part 32 Opening 33 Discharge port 34 Shaft seal 41 Holding part 42 Cylindrical part 43 Blade 44 Opening 45 Key 51 Holding part 52 Cylindrical part 53 Blade 54 Opening 55 Bolt 56 Space part 61 Water supply port 62 Drainage port

Claims (4)

A cylindrical dispersion tank closed at one end;
A hollow rotating shaft that is rotatably inserted through the other end of the dispersion tank;
An outer rotor that includes a plurality of blades arranged in a cylindrical shape and generates a centrifugal force by rotating while being fixed to the rotating shaft;
A plurality of blades arranged in a cylindrical shape located inside the outer rotor, and having an inner rotor that generates centrifugal force by being fixed to the rotating shaft and rotating;
The dispersion tank includes a supply port communicating between the inside and outside of the dispersion tank;
The media agitation type wet disperser characterized in that the hollow portion of the rotating shaft communicates with the inside of the inner rotor to form a discharge port.   The media stirring type wet disperser according to claim 1, wherein the plurality of blades of the outer rotor are provided closer to the one end of the dispersion tank than the plurality of blades of the inner rotor.   The media stirring type wet disperser according to claim 1, wherein the supply port is provided at the other end of the dispersion tank.   The media agitation type wet disperser according to any one of claims 1 to 3, wherein the dispersion tank includes a cooling jacket on the outside thereof.

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