JPH05170801A - Agitator - Google Patents

Abstract

PURPOSE:To provide an agitation system which can give fine polymer particles of a very sharp particle diameter distribution when applied to the emulsification/ dispersion/granulation process. CONSTITUTION:An agitator to be used in emulsification/dispersion/granulation or suspension polymerization and manufactured by attaching a turbine 5 to the lower end of a turbine shaft 4 extended from a drive 13 and having a turbine stirrer 3 formed by surrounding the turbine 5 with a casing 8 having a liquid suction inlet on the lower position of the turbine and a liquid outlet on the upper part of the turbine in an agitation tank 1, wherein the upper part of the casing of the turbine stirrer is provided with a cylindrical body 9 elongated in the direction of the turbine shaft.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stirring device. More specifically, the present invention relates to an improvement in the shape of a stirring device provided with a turbine-type stirrer in a stirring tank used for producing polymer particles by emulsion dispersion granulation or suspension polymerization.

[0002]

2. Description of the Related Art A seed polymerization method is known as a method for producing fine polymer particles having a uniform particle size of about 1 to 10 .mu.m. In this method, it is necessary to strictly control the polymerization conditions such as temperature. is there. Further, since the resin used is also limited and the process becomes complicated, the manufacturing cost is high and it cannot be said to be a very practical method. Therefore, the emulsion dispersion granulation method is being studied as one of the methods that can simplify the manufacturing process, lead to cost reduction, and have a wide selection range of resins to be used. In this method, the polymer polymerization process is omitted, and the polymer solution prepared by dissolving the polymer in a water-insoluble organic solvent is directly emulsified and dispersed in an aqueous dispersion to form an emulsion. It is carried out by applying heat to evaporate and dry the organic solvent to precipitate fine polymer particles.

In such an emulsion dispersion granulation method, it is the emulsion dispersion step of the polymer solution in the aqueous dispersion medium that determines the particle size and particle size distribution of the polymer particles obtained.
Further, a stirring system used in this emulsifying and dispersing step is considered as one that greatly influences the particle size distribution of the obtained polymer solution.

Regarding the method for producing polymer fine particles by the emulsion dispersion granulation method, for example, Japanese Patent Publication No. 61-28888, Japanese Patent Laid-Open No. 61-91666, and Japanese Patent Laid-Open No. 63-25.
It is disclosed in documents such as Japanese Patent No. 664. However,
In these documents, it is shown that various types of stirrer such as paddle stirrer, high shear turbine stirrer or ultrasonic disperser are used, but other points in the stirrer system are particularly mentioned. Not not.

The factors that generally govern the droplet size distribution in a liquid-liquid dispersion system are considered as follows. In the stirring tank, as shown schematically in FIG. 18, a region (impeller region) I where only droplet breakup occurs in the vicinity of the stirring blade 14.
And other areas (circulation areas) R. The circulation paths of the droplets from the impeller region I are various, and the difference in the circulation frequency experienced by individual droplets is an important factor that governs the droplet size distribution.

In the range where the viscosity of the droplet is less than a certain viscosity, the interfacial tension governs the droplet diameter, and when the viscosity is higher than that, the viscous force dominates. In the case of a polymer solution in which the viscous force controls the droplet diameter, the droplet diameter is determined by the stirring force in the impeller region I, and the droplet diameter distribution is determined by the difference in circulation frequency. Is. That is, if there is no difference in the circulation frequency, droplets having a uniform particle size should be obtained.

[0007]

DISCLOSURE OF THE INVENTION The present inventors consider that the shape of a stirrer in a stirrer greatly influences the particle size distribution of polymer fine particles obtained by an emulsion dispersion granulation method or the like. It has been examined.

The present invention aims to provide an improved stirrer. It is another object of the present invention to provide a stirring device which is used in an emulsion dispersion granulation method, a suspension polymerization method or the like and which can control the particle size of the obtained polymer fine particles to be uniform.

[0009]

[Means for Attempting to Solve the Problems]
A turbine-type stirrer, in which a turbine is attached to the lower end of a turbine shaft extended from a drive unit, and the turbine is surrounded by a casing having a liquid suction port below the turbine and a liquid discharge hole above the turbine, A stirring device used for emulsion dispersion granulation or suspension polymerization provided inside, characterized in that a cylindrical body extending in the turbine axial direction is provided at the upper part of the casing of the turbine type stirrer. Achieved by the device.

The present invention further shows a stirrer, further comprising an umbrella-shaped body having a surface that extends downward from the upper end of the cylindrical body in the substantially circumferential direction. .. The present invention further comprises a dome-shaped roof having a surface extending in the upper space adjacent to the upper end of the tubular body while hanging outward in substantially the entire circumferential direction around the turbine shaft. It shows a stirring device.

[0011]

As described above, the factor that governs the droplet size distribution in a liquid-liquid dispersion system is the difference in the circulation frequency experienced by individual droplets. If there is no difference in this circulation frequency, a uniform particle size is obtained. Droplets can be obtained. When the turbine type stirrer is used, the impeller area I is the portion shown in FIG. 19, and in order to eliminate the variation in the circulation frequency, the shape of the stirrer must be determined so that the entire liquid can pass through the impeller area I the same number of times. is necessary. As a result of intensive studies by the present inventors, the flow provided to the fluid by the rotation of the turbine was not sufficient to form a circulating flow over the entire region of the liquid contained in the stirring tank, and the fluid was contained in the stirring tank. It was found that the circulation flow of the liquid becomes weak near the liquid surface of the liquid, especially near the wall surface of the stirring tank, which has a great influence on the variation of the circulation frequency. As a result of further research based on this finding, a cylindrical body was provided in the upper part of the casing surrounding the turbine of the turbine stirrer, and the liquid passing through the impeller region of the stirrer was forced to flow upward inside the cylindrical body. It has been found that, when the liquid is guided to the liquid surface portion through a passage, the liquid circulation in the tank becomes good, and the particle size distribution of the obtained droplets becomes extremely good. Further, a dome-shaped roof is provided in the umbrella-shaped body extending outward from the upper end of the tubular body or in the upper space of the tubular body, and the tubular body flow is controlled by the upper surface of the umbrella-shaped body or the lower surface of the roof. It was found that when the flow passing through the passage is guided outward from the center of the stirring tank, the particle size distribution of the obtained droplets becomes even better.

Hereinafter, the present invention will be described in more detail based on embodiments. The stirrer of the present invention is a stirrer equipped with a turbine stirrer having a high shearing force, and is preferably used when polymer fine particles are to be obtained by, for example, an emulsion dispersion granulation method or a suspension polymerization method. ..

There is no particular limitation on the shape and size of the stirring tank 1 used in the stirring apparatus according to the present invention, and a generally used flat bottom stirring tank may be used. As shown in a) and (b), it has a substantially cylindrical side surface portion and a shape in which the lower end portion of the side surface portion decreases in diameter toward the axis of the agitation tank while decreasing in diameter and the central portion through which the axis passes is deepest. It is desirable to have a bottom portion 2 and, for example, as shown in FIGS. 16 (a) and 16 (b), a liquid reservoir 2a having an inner diameter slightly larger than the outer diameter of the turbine-type stirrer used is provided at the center portion of the bottom portion 2. What you are doing is desired.

The turbine-type stirrer 3 used in the stirrer of the present invention has a structure as shown in FIG. 7, for example. In the stirrer 3 shown in FIG. 7, a turbine 5 is attached to the tip of a turbine shaft 4 extended from an upper drive motor (not shown), and the outer periphery of the turbine 5 serves as a stator 6 which also serves as a turbine bearing. It is covered with a casing 8 composed of a bottom plate 7 joined to its lower end surface.
By the rotation of the turbine 5, the liquid is sucked into the inside of the casing 8 through the opening 7a provided at the center of the bottom plate 7 and discharged to the outside of the casing 8 through the opening 6a provided at the upper wall surface of the stator 6. Be done. The inside of the casing 8 is the impeller region I, and a high shearing force is applied to the passing liquid in the vicinity of the turbine blade, and the droplets are broken. Turbine stirrer 3 used in the present invention
The turbine 5 has many shapes, for example, the viscosity of a liquid such as a high viscosity one having a shape as shown in FIG. 8A and a low viscosity one having a shape as shown in FIG. 8B. It can be appropriately selected according to 8A to FIG. 9A.
Another embodiment of the stirrer 3 equipped with the high-viscosity turbine 5 as shown in (a), and FIG. 9 (b) shows the stirrer 3 equipped with the low-viscosity turbine as shown in FIG. 8 (b). Another embodiment of the above is shown, but these have substantially the same configuration as that illustrated in FIG. 7 except that the shape and the like of the casing 8 are slightly different. As a turbine type stirrer used in the stirrer of the present invention, a homomixer (made by Tokushu Kika Co., Ltd.) and the like are known.

In the stirrer of the present invention, however, as shown in FIG. 1, a tubular body 9 extending in the direction of the turbine shaft 4 is provided above the casing 8 of the turbine stirrer 3. The shape of the tubular body 9 is not particularly limited, but its cross-sectional shape is preferably a polygon having a regular hexagon or more, a circle or an ellipse, and its diameter is at least at its lower end portion. The outer diameter of the casing 8 of the turbine agitator 3 may be equal to or smaller than that. The diameter may be gradually increased from the lower end toward the upper end. In particular, it is most preferable that the cylinder has a circular cross-sectional shape and the diameter of the cylinder is equal to the outer diameter of the casing 8 of the turbine agitator 3. The length of the tubular body 9 can be changed according to the amount of liquid stored in the stirring tank 1 at the time of stirring, but within a range in which the volume of the internal space of the tubular body 9 becomes smaller than the liquid amount, It may be determined according to the outer diameter of the casing 8.

Further, in the stirring device of the present invention, FIG.
As shown in, it is preferable to further include an umbrella-shaped body 10 having a surface that spreads outward from the upper end portion of the tubular body 9 in a substantially circumferential direction. Note that FIG. 10 is a schematic perspective view showing a state where the tubular body 9 and the umbrella-shaped body 10 are attached to the casing of the turbine-type stirrer, and FIG. 11 is a side view of the umbrella-shaped body 10. The shape of the umbrella-shaped body 10, for example, the inclination angle of the upper surface of the umbrella-shaped body 10 is not particularly limited. Although not particularly limited as long as its size is also the outside diameter of the umbrella-shaped body 10 is smaller than the inner diameter of the stirring vessel 1, the outer diameter of the umbrella-shaped body 10 as shown in FIG. 12 as d _1, agitation When the inner diameter of tank 1 is D, 0 <
(D-d ₁ ) /D≦0.5, more preferably 0.1 ≦
It is desirable that the condition of (D−d ₁ ) /D≦0.3 is satisfied. This is because if the outer diameter d ₁ of the umbrella-shaped body 10 is less than 0.5 times the inner diameter D of the stirring tank 1, the effect of improving the circulation of the liquid due to the provision of the umbrella-shaped body 10 is not sufficiently exerted. is there.

Alternatively, as shown in FIG. 3, in the upper space near the upper end of the cylindrical body 9, a surface that spreads while hanging outward in substantially the entire circumferential direction around the turbine shaft 4 is provided. It is desirable to further include a dome-shaped roof 11 having. The roof 11 functions substantially similarly to the umbrella-shaped body 10, and the shape of the roof 11, for example, the inclination angle of the lower surface of the roof 11 is not particularly limited. The size is not particularly limited as long as the outer diameter of the umbrella-shaped body 10 is smaller than the inner diameter of the stirring tank 1, but the outer diameter of the roof 11 is set to d _{2 as} shown in FIG.
When the inner diameter of the stirring tank 1 is D, 0 <(D-d ₂ ) / D
≦ 0.5, more preferably 0.1 ≦ (D−d ₂ ) / D ≦
It is desirable that the condition of 0.3 is satisfied. This is because if the outer diameter d ₂ of the roof 11 is less than 0.5 times the inner diameter D of the stirring tank 1, the effect of improving the circulation of the liquid due to the provision of the roof 11 cannot be sufficiently exhibited. Further, the position of the roof 11 may be any height as long as it can sufficiently interfere with the flow of the liquid discharged through the inside of the tubular body 9, depending on the turbine speed of the turbine stirrer, the viscosity of the liquid, and the like. Just decide. The roof 11 may be attached to the turbine shaft cover portion 12 that covers the outer periphery of the turbine shaft 4 of the turbine-type stirrer.

Further, in the stirring device of the present invention, FIG.
As shown in FIG. 2, the distance (l) between the bottom of the stirring tank and the bottom of the turbine-type stirrer is 0.2d ₃ ≦ l ≦ 3d _{3 with} respect to the diameter (d ₃ ) of the homomixer, and more preferably 0. .5
It is desirable that the relationship of d ₃ ≦ l ≦ 1.5d ₃ is satisfied. This is because if l is less than 0.5d ₃ , cavitation may occur during stirring, while if l is more than 3d ₃ , circulation of the liquid in the tank may not be good. Is.

Next, the case where the polymer fine particles are produced by the emulsion dispersion granulation method using the stirring apparatus of the present invention as described above will be exemplified. First, the polymer is dissolved in a water-insoluble organic solvent to prepare a polymer solution. The polymer to be used may be any polymer as long as it is soluble in a water-insoluble organic solvent and insoluble in water or almost insoluble in water, for example, polystyrene, styrene-acrylic copolymer, polyvinyl chloride, polyacetic acid. Polymers such as vinyl, polymethacrylic acid ester, polyacrylic acid ester, epoxy resin, polyethylene, polyurethane, polyamide and paraffin wax may be used alone or in a blend. As the solvent used, any solvent may be used as long as it is insoluble or hardly soluble in water and can dissolve the polymer as described above.
Particularly preferred are toluene, methylene chloride,
1,2-dichloroethane, carbon tetrachloride, chloroform,
Diethyl ether, methyl ethyl ketone, ethyl acetate,
Examples include benzene. In addition, these non-water-soluble organic solvents may be used alone or in combination of two or more kinds.

In this polymer solution, other solid components such as various known colorants, various charge control agents, various magnetic substances, etc. are dissolved or dispersed depending on the intended use of the polymer fine particles to be obtained. can do.

The polymer solution thus prepared is then mixed with the aqueous dispersion and, for example, as illustrated in FIGS. 1 to 6, a cylinder is provided above the casing 8 of the turbine stirrer 3 installed in the stirring tank 1. By sufficiently stirring with the stirrer of the present invention provided with the particles 9, the emulsion is emulsified and dispersed in the aqueous dispersion. Note that FIG.
Reference numeral 13 in FIGS. 6 to 6 indicates a drive device of the turbine agitator 3. The stirring time at this time is preferably 10 minutes or more. This is because if the stirring time is too short, a sharp particle size distribution cannot be obtained. The turbine speed of the turbine-type stirrer 3 changes depending on the height of the cylindrical body 9 mounted on the upper part of the casing 8 of the stirrer 3, the viscosity of the liquid to be stirred, and the like. The number of rotations may be set so that the liquid that has passed through is overflowed, but the number of rotations of at least 2000 rpm or more is required. Further, since the particle size of each droplet of the polymer solution in the emulsion directly affects the size of the finally obtained polymer fine particles, a droplet is formed according to the size of the polymer fine particles to be obtained. There is a need to.

As the aqueous dispersion used to form the emulsion, water can basically be used,
A water-soluble organic solvent that does not destroy the emulsion may be contained. For example, water, water / methanol mixed liquid (weight ratio 50/50 to 100/0), water / ethanol mixed liquid (weight ratio 50/50 to 100/0), water / acetone mixed liquid (50/50 to 100/0), A water / methyl ethyl ketone mixed solution (weight ratio (70/30 to 100/0), etc. can be used. When forming such an emulsion, a dispersion stabilizer or a dispersion stabilization auxiliary agent may be added if necessary. Dispersion stabilizers are those that have hydrophilic colloids in aqueous dispersions, especially gelatin, gum arabic, agar, cellulose derivatives (eg hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, etc.), synthetic high Molecule (polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, polyacrylate, polymethacrylate A surfactant is usually used as the dispersion stabilizing auxiliary, and a natural surfactant such as saponin, a nonionic surfactant such as alkylene oxide, glycerin, and glycidol, a carboxylic acid. , An anionic surfactant containing an acidic group such as sulfonic acid, phosphoric acid, a sulfuric acid ester group, a phosphoric acid ester group, etc. In particular, a combination of a dispersion stabilizer and a dispersion stabilization auxiliary agent is preferably a cellulose derivative (methylcellulose derivative). Cellulose derivatives) and anionic surfactants (sodium dodecylbenzenesulfonate) or polyvinyl alcohol and anionic surfactants.

After forming the emulsion as described above, the temperature of the entire system is gradually raised to completely remove the solvent in the droplets. Then, polymer fine particles are obtained through a washing-filtering-drying process.

As described above, by using the stirring apparatus according to the present invention in the stirring system of the emulsion dispersion granulation method, it is possible to obtain polymer fine particles having an average particle size of about 1 to 10 μm and having an extremely sharp particle size distribution. The stirring device of the present invention can be suitably applied to a stirring system in suspension polymerization.

[0025]

EXAMPLES The present invention will be described in more detail below with reference to examples.

Example 1 100 g of low molecular weight polyester was completely dissolved in 450 g of methylene chloride at room temperature to give 550 g of a polymer solution.
To prepare. On the other hand, 10 g of sodium dodecylbenzenesulfonate and 10 g of METOLOSE 65SH-50 (manufactured by Shin-Etsu Chemical Co., Ltd., a methylcellulose derivative) are completely dissolved in 1 liter of water without heating and an aqueous dispersion is prepared. Next, as shown in FIG. 1, 1 liter of the aqueous dispersion was placed in a flat-bottomed stirring tank, the tubular body was placed on the upper part of the casing of a TK homomixer (manufactured by Tokushu Kiko Co., Ltd.), and this homomixer was used for 10 minutes. By stirring at 4000 rpm, 550 g of the polymer solution was emulsified and dispersed. Then, pour the obtained emulsion into 1 liter of water contained in a 3 liter beaker and keep it at about 45 ° C for 2 hours while slowly stirring at 500 rpm with a three-one motor to completely remove methylene chloride. did. The volume average particle size of the polymer fine particles thus obtained and its standard deviation were measured using a particle size distribution measuring device (SALD1000 manufactured by Shimadzu Corporation). The results obtained are shown in Table 1.

Example 2 Polymer fine particles were produced in the same manner as in Example 1 except that a homomixer equipped with a tubular body and an umbrella-shaped body as shown in FIG. 2 was used. The outer diameter of the umbrella-shaped body was 0.8 times the inner diameter of the stirring tank. The volume average particle diameter of the obtained polymer fine particles and the standard deviation thereof were measured using a particle size distribution measuring device (SALD1000 manufactured by Shimadzu Corporation). The results are shown in Table 1. Further, FIG. 17 shows a graph of the particle size distribution of the obtained polymer particles.

Example 3 Polymer fine particles were produced in the same manner as in Example 1 except that a homomixer equipped with a cylindrical body and a dome-shaped roof as shown in FIG. 3 was used. The outer diameter of the dome-shaped roof was 0.8 times the inner diameter of the stirring tank. The volume average particle diameter of the obtained polymer fine particles and its standard deviation are measured by a particle size distribution measuring device (SALD100 manufactured by Shimadzu Corporation).
0) was used. The results are shown in Table 1.

Example 4 Polymer fine particles were produced in the same manner as in Example 1 except that a stirring tank having a bottom as shown in FIG. 4 was used. The volume average particle size of the obtained polymer fine particles and its standard deviation are measured by a particle size distribution measuring device (manufactured by Shimadzu Corporation,
SALD1000) was used for the measurement. The results are shown in Table 1.

Example 5 Polymer fine particles were produced in the same manner as in Example 2 except that a stirring tank having a bottom as shown in FIG. 5 was used. The volume average particle size of the obtained polymer fine particles and its standard deviation are measured by a particle size distribution measuring device (manufactured by Shimadzu Corporation,
SALD1000) was used for the measurement. The results are shown in Table 1.

Example 6 Polymer fine particles were produced in the same manner as in Example 2 except that a stirring tank having a bottom as shown in FIG. 6 was used. The volume average particle size of the obtained polymer fine particles and its standard deviation are measured by a particle size distribution measuring device (manufactured by Shimadzu Corporation,
SALD1000) was used for the measurement. The results are shown in Table 1.

Comparative Example Polymer fine particles were produced in the same manner as in Example 1 except that a cylindrical body was not attached to the casing upper part of the homomixer as shown in FIG. The standard deviation was measured using a particle size distribution measuring device (SALD1000 manufactured by Shimadzu Corporation). The results are shown in Table 1.

[0033]

[Table 1]

As shown in Table 1, the standard deviation of each example was much smaller than that of the comparative example, and the particle size distribution was very good. In addition, in each of the above Examples and Comparative Examples, the standard deviation of the average particle diameter was calculated by the following formula.

[0035]

[Equation 1]

[0036]

As described above, according to the present invention, the turbine is attached to the lower end of the turbine shaft extended from the drive unit, and the casing has the liquid suction port below the turbine and the liquid discharge port above the turbine. A turbine-type stirrer surrounding the turbine with an agitator for use in emulsion dispersion granulation or suspension polymerization provided in a stirring tank, the turbine-type stirrer being extended in the turbine axial direction at the upper part of the casing of the turbine-type stirrer. Since it is a stirrer characterized in that it is provided with a cylindrical body, the circulation frequency experienced by each droplet in the liquid-liquid dispersion system is made uniform, and then obtained by emulsion dispersion granulation or suspension polymerization. The obtained polymer fine particles can have an extremely sharp particle size distribution.

Further, the stirring device according to the present invention is provided with an umbrella-shaped body having a surface that spreads while hanging outward in substantially the entire circumferential direction from the upper end of the cylindrical body, or on the upper end of the cylindrical body. The adjacent upper space is provided with a dome-shaped roof having a surface that spreads while hanging outward in substantially the entire circumferential direction around the turbine axis, and the stirring tank has a substantially cylindrical side surface. And a bottom portion having a shape in which the central portion through which the axis passes and which has the deepest shape is obtained by descending while reducing the diameter from the lower end of the side surface portion toward the axis of the stirring tank. The diameter distribution is expected to become even sharper.

[Brief description of drawings]

[Figure 1]

FIG. 6 is a schematic diagram showing a configuration of an embodiment of the stirrer of the present invention in use,

FIG. 7 is a schematic side sectional view showing an embodiment of a turbine-type stirrer used in the stirrer of the present invention,

8A and 8B are schematic perspective views showing one embodiment of a turbine of a turbine-type stirrer,

9A and 9B are schematic side sectional views showing a state in which the turbine of FIGS. 8A and 8B is mounted on a stator,

FIG. 10 is a schematic perspective view showing the shapes of the tubular body and the umbrella-shaped article provided in one embodiment of the present invention,

FIG. 11 is a schematic side view showing the shapes of a tubular body and an umbrella-shaped article provided in one embodiment of the present invention,

FIG. 12 is a schematic cross-sectional view showing the relationship between the inner diameter (D) of the stirring tank and the outer diameter (d ₁ ) of the umbrella-shaped article in the stirring device of the present invention,

FIG. 13 is a schematic cross-sectional view showing the relationship between the inner diameter (D) of the stirring tank and the outer diameter (d ₂ ) of the dome-shaped roof in the stirring apparatus of the present invention,

FIG. 14 is a schematic cross-sectional view showing the relationship between the distance (l) between the bottom of the turbine-type stirrer and the bottom of the stirring tank and the outer diameter (d ₃ ) of the turbine-type stirrer in the stirrer of the present invention,

15 (a) and 15 (b) are schematic cross-sectional views each showing the shape of one embodiment of a stirring tank used in the stirring device of the present invention,

16 (a) and 16 (b) are schematic cross-sectional views each showing the shape of yet another embodiment of the stirring tank used in the stirring device of the present invention,

FIG. 17 is a graph showing a particle size distribution of polymer fine particles obtained according to an example of the present invention,

FIG. 18 is a schematic diagram of a liquid-liquid dispersion system in a stirring tank,

FIG. 19 is a schematic diagram showing an impeller region and a circulation region when a turbine-type stirrer is used,

FIG. 20 is a schematic diagram showing a configuration of a stirring device used in a comparative example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Stirring tank, 2 ... Bottom of stirring tank, 2a ... Liquid reservoir, 3 ... Turbine type stirrer, 4 ... Turbine shaft, 5 ... Turbine, 6 ...
Stator, 7 ... Bottom plate, 8 ... Casing, 9 ... Cylindrical body,
10 ... Umbrella, 11 ... Dome roof, 12 ... Turbine shaft cover part, 13 ... Drive device, 14 ... Stirring blade, I ... Impeller region, R ... Circulation region.

Claims (5)

[Claims] 1. A turbine type in which a turbine is attached to a lower end of a turbine shaft extended from a drive unit, and the turbine is surrounded by a casing having a liquid suction port below the turbine and a liquid discharge port above the turbine. A stirrer for use in emulsion dispersion granulation or suspension polymerization, comprising a stirrer in a stirrer, wherein a cylindrical body extending in the turbine axial direction is provided at the upper part of the casing of the turbine type stirrer. A stirrer characterized by. 2. The stirrer further comprises an umbrella-shaped body having a surface that spreads downward from the upper end of the cylindrical body in the substantially entire circumferential direction. The stirrer according to Item 1. 3. The agitating device has a dome-shaped roof having a surface that spreads downward in an upper space near the upper end of the tubular body substantially in the entire circumferential direction around the turbine shaft. The stirring device according to claim 1, further comprising: 4. The stirring tank has a substantially cylindrical side surface portion and a bottom portion having a shape in which a lower end of the side surface portion is shrunk while decreasing in diameter toward an axis of the stirring tank and a central portion through which the axis passes is deepest. The stirrer according to any one of claims 1 to 3, further comprising: 5. The stirrer according to claim 4, wherein a liquid reservoir is formed at the center of the bottom of the stirring tank.