JP4593343B2 - Method for producing latex - Google Patents

Description

  The present invention provides a liquid-liquid mixing, a gas-liquid mixing, a solid-liquid mixing, a gas-liquid-solid mixing, a liquid-liquid, gas-liquid, solid-liquid, CG (coagulum) and coarseness in the production of polymer latex using a stirrer for efficient gas-liquid-solid reaction and distillation / concentration, crystallization, dissolution, suspension, dispersion, etc. It solves various problems such as a decrease in heat transfer performance accompanying an increase in the amount of particles and a higher concentration (higher viscosity), and an increase in tank pressure during addition of the monomer emulsion during the reaction.

For example, when producing a polymer latex, a stirring device equipped with a stirring blade is used. Various conventional stirring devices are known. The height of the liquid with respect to the inner diameter of the tank of the agitator varies depending on the form of the reaction, but the height of the liquid is increased for reasons such as increasing the heat transfer performance per volume and increasing productivity. A high-liquid-depth polymerization stirring apparatus exceeding 2.0 is also preferably used as a polymerization reaction stirring apparatus.
As a stirring blade used in such a high liquid depth type stirring device, for example, one using a multi-stage inclined paddle blade is known. In addition, when the value is less than 2.0, one using a large wing such as an anchor wing or a helical ribbon wing is known.

  However, when a polymer latex is to be produced using this conventional stirring device having a stirring blade, CG (coagulum) or coarse particle amount due to poor vertical mixing, high shear stress, etc. There were various problems such as a decrease in heat transfer performance due to an increase or a high concentration (high viscosity), and an increase in the internal pressure of the tank during addition of the monomer emulsion during the reaction.

  In addition, as shown in JP-A-7-278210 and JP-A-7-292002, an agitation apparatus having two or more stages of flat paddle blades along an agitation rotating shaft is also known.

  However, since the stirrers shown in these publications have multi-stage flat paddle blades along the stirring rotation axis, a flow retention portion between the blades is generated, and there is a difficulty in uniform mixing performance. It became clear by experiment of inventors. In particular, it was found that the uniform mixing performance improved or deteriorated due to the difference in the height of the liquid with respect to the shape of the tank, that is, the inner diameter of the tank of the stirring device.

  Furthermore, as shown in JP-A-61-200842 and JP-A-6-312122, a stirring device having a grid-like stirring blade has been developed.

  According to the stirrer having the lattice-shaped stirrer blade, compared with a stirrer having a multi-stage inclined paddle blade or a stirrer having a multi-stage flat paddle blade, the uniform mixing characteristics are improved and the amount of coarse particles of polymerization is increased. It has been found by experiments by the present inventors that this can be reduced.

  However, for example, in the production of latex, it is desired to further improve the uniform mixing characteristics and to further reduce the amount of coarse particles of CG and polymerization.

  Furthermore, the use of blades including a bottom paddle part, an arm part, and first and second strip parts has been shown to reduce coarse particles due to CG and polymerization. It is limited to a high-liquid-depth polymerization stirring apparatus having a height exceeding 2.0, and the low-cost method of exchanging only the stirring blades of the currently owned reactor can exhibit the invention effect. It was not possible and lacked versatility (for example, refer to Patent Document 1).

Japanese Patent Laid-Open No. 10-33966

  The present invention has been made in view of such a situation, and can be easily realized in a general reaction apparatus, for example, generation of CG, which is a problem in the production of latex, and coarse particles which are important characteristics in latex quality. An object is to provide a stirring blade and a polymerization reaction method capable of reducing the amount as much as possible.

  As a result of intensive studies, the present inventor has provided a stirring shaft in the central part of the vertical cylindrical stirring device, and arranged the wide paddle blade close to the bottom of the tank on the stirring shaft, and further the upper portion of the wide paddle blade. One or more H-shaped paddle blades are arranged on the stirring shaft, the H-shaped paddle blade is preceded by the lower stirring blade vertically adjacent to the rotation direction, and a part of the stirring blade adjacent vertically It has been found that providing the overlap solves the above problem.

That is, the present invention provides a stirring shaft in the central part of a bowl-shaped cylindrical stirring tank, and a wide paddle blade is disposed on the stirring shaft so as to be close to the bottom of the tank. One or more H-type paddle blades are arranged on the upper side, and the H-type paddle blades are preceded by a crossing angle of 0.1 to 90 ° with respect to the lower stirring blade vertically adjacent to the rotation direction. perform stirring with a stirring device, characterized in that which gave overlapping a portion of the stirring blade adjacent to a manufacturing method of Lula Tex cause polymerization reaction,
The stirring device is
(1) A wide paddle blade having a recess at the center of the upper end is disposed on the stirring shaft so as to be close to the bottom of the tank,
(2) The wide paddle blade diameter ratio with respect to the stirring tank inner diameter is in the range of 0.6 to 0.8;
(3) An H-type paddle blade is disposed on the stirring shaft above the wide paddle blade,
(4) The blade diameter of the H-type paddle blade is in the range of 1/3 to 3/4 of the blade diameter of the wide paddle blade.
(5) The H-type paddle blade is preceded by a crossing angle of 30 to 60 degrees with respect to the rotation direction than the wide paddle blade,
(6) The H-type paddle blade and the wide paddle blade have an overlap of 1% to 50% with respect to the height in the stirring axis direction of the wide paddle blade,
(7) The degree of overlap between the H-type paddle blade and the wide paddle blade is such that the vicinity of the stirring shaft is thin and thick at a distance from the stirring shaft,
(8) Provided is a method for producing latex , wherein the length of the H-type paddle blade in the vertical direction is in the range of 1/2 to 4 of the blade diameter of the H-type paddle blade .

  According to the present invention, the amount of coarse particles that are important in quality can be reduced as much as possible.

  The stirring blade of the present invention will be described. FIG. 1 is a schematic view showing an embodiment of a stirring device according to the present invention.

  At the bottom of the stirring tank 1, a wide paddle blade 3 disposed on the stirring shaft 2 and an H-type paddle blade 4 disposed on the same stirring shaft at the top thereof, the wide paddle blade 3 has a lower end. The part is placed near the bottom wall surface of the stirring tank and placed at the bottom of the tank, and the tip of the blade is retreated with respect to the rotation direction.

  Since the wide paddle blade 3 is preferably of a shape that is sufficiently large to form a circulating flow throughout the tank, the ratio of the blade diameter to the tank inner diameter (d / D) is 0.6 to 0.8. (For example, 0.77 in FIG. 1 and 0.6 in FIG. 2).

  Further, the blade height ratio (h / L) of the wide paddle blade 3 to the tank body length is preferably in the range of 0.2 to 0.5, but generally the blade height is expressed as a ratio to the tank inner diameter. According to this expression, the ratio of the blade height to the tank inner diameter (h / D) is preferably 0.3 to 0.5 (for example, h / D = 0.3 in FIG. 1). In FIG. 2, it is 0.45).

  The H-type paddle blade 4 is used in one or a plurality of stages depending on the situation, but in the present embodiment, the case where the single-stage H-type paddle blade 4 is used is shown. When the H-type paddle blade 4 has a single stage, it is placed ahead of the wide paddle blade 3 installed at the bottom of the tank at an intersection angle in the range of 0 to 90 °, more preferably 30 to 60 ° with respect to the rotation direction. In addition, the wide paddle blade 3 and the H-type paddle blade 4 overlap each other in the axial direction.

  In addition, as an agitation device having the positional relationship of each member described above, another embodiment as shown in FIG. 2 and an H-type paddle blade connected to secure the strength of the blade as shown in FIG. Such a modified H-type paddle blade 4 may be used.

  Further, as shown in FIG. 4, when a plurality of H-type paddle blades are used (in FIG. 4, the H-type paddle blade 4 and the H-type paddle blade 4 ′ are used in two stages), the upper H-type paddle is used. The wing 4 'is disposed ahead of the H-type paddle wing 4 positioned below at a crossing angle in the range of 0.1 to 90 °, preferably 30 to 60 ° with respect to the rotational direction, and vertically. The H-type paddle blade 4 that overlaps with the adjacent agitating blades in the axial direction and has a lower H-type paddle blade 4 than the wide paddle blade 3 by 0.1 to 90 °, preferably 30 to 60 °. Arrange them ahead of the intersection of the range.

In this case, it is preferable to select the crossing angle of each blade so that the rotation shaft rotates in a balanced manner. For example, when two H-type paddle blades are used as shown in FIG. 4 may be preceded by a crossing angle of 45 ° from the lower H-type paddle blade 4 ′, and the lower H-type paddle blade 4 ′ may be preceded by a crossing angle of 45 ° from the wide paddle blade 3.
The H-type paddle blade 4 or 4 'preferably has a longer axial length (blade height: hs) than the radius of the blade diameter (1/2 of the blade span ds). In consideration of the above restrictions and the use of a plurality of stages of H-type paddle blades, it is preferable that the range is 1/2 · ds ≦ hs ≦ 4 · ds.

The blade span generally refers to the widest part of the blade.
Further, the vertically long blade extending in the vertical direction of the stirring shaft at the tip of the blade is preferably a structure that is parallel to the stirring shaft or has a slight angle.
The H-type paddle blade and the wide paddle blade may have various shapes as shown in FIG. That is, the H-type paddle blade may be a complete H-shape, a substantially C-shape, or an H-shape having a taper. The longitudinal blade at the tip of the H-type paddle blade with respect to the width direction has a range of 0.1 ° (parallel to the axis) ≦ θ ≦ 30 °, where θ is the angle between the vertical side and the stirring shaft When the width of the vertically long blade is not parallel, it is preferable that the angle is in the range of 0.1 ° ≦ θin (inner side angle) ≦ θout (outer side angle) ≦ 30 °.

The blade diameter (blade span: ds) of the H-type paddle blade is preferably smaller than the blade diameter (blade span: d) of the wide paddle blade installed at the lowermost stage, and 1/3 · d ≦ ds ≦ 3 / The range of 4 · d is particularly preferable. Further, the distance between the vertical axis (inner side) adjacent to the stirring shaft of the vertically long blade at the tip of the H-type paddle blade and the stirring shaft is equal to the inner diameter D of the stirring tank in consideration of the stirring efficiency. It is preferable to set it as 2% or more, and it is preferable to set it as 15% or less.
Further, the paddle portion that supports the vertically long blade may be inclined so as to generate a downward flow in the vicinity of the stirring shaft. Furthermore, a rectifying means 5 (jammer plate) that inhibits fluid swirling (so-called rotation) may be installed on the inner wall surface of the stirring tank.

As this rectification | straightening means 5, the plate-shaped member which has a width | variety of about 2 to 15% of the stirring tank inner diameter D, and a round bar-shaped member can be used. Next, the movement of the fluid when another liquid is poured into the liquid from the top will be described with reference to FIG. Depending on the form of the polymerization reaction, various additives such as additional monomers, emulsifiers and dispersants may be charged from the top during the reaction, and these charges may have a difference in specific gravity from the liquid part during the reaction. Because there are many, it is important to be transported quickly and uniformly in the system. The powder charged in the stirring tank is drawn to the vicinity of the stirring shaft while drawing a spiral on the liquid surface along the flow of the liquid while floating on the liquid surface.
A downward flow is generated in the vicinity of the stirring shaft, and the powder is drawn into the liquid by the downward flow. At this time, the powder is drawn into the liquid along the stirring shaft, but is not drawn in close contact with the stirring shaft, and is placed at a slight distance from the stirring shaft in the vertical direction of the vertical blade of the H-type paddle blade. It draws in a spiral with a spread across the inner side.
For this reason, most of the powder is drawn into the liquid without contacting the stirring shaft, and adhesion of the powder to the stirring shaft can be reduced.

  When the powder drawn into the liquid moves to the vicinity of the upper end of the wide paddle blade installed at the bottom of the stirring tank while drawing a spiral along the stirring shaft without contacting the stirring shaft, It passes through and is drawn into the portion of the back side where the negative pressure is the most with respect to the rotation direction of the wide paddle blade, and is further discharged toward the stirring tank wall surface by the discharge flow generated by the wide paddle blade.

The liquid discharged by the wide paddle blade along with the liquid toward the stirring tank wall surface rises to the upper part of the stirring tank along the wall surface by converting the liquid flow into an upward flow, and the liquid flow is stirred near the liquid surface. By converting to the tank center direction, it circulates to the stirring tank center.
In addition to such a large circulating flow in the vertical direction over the entire stirring tank, the injected liquid is liquefied by the horizontal mixing flow generated by the H-type paddle blade and the shear mixing of the H-type paddle blade and the wide paddle blade. Evenly dispersed in.

In the stirring apparatus of the present invention, the wide paddle blade installed at the bottom of the lowermost tank acts as the main stirring blade, and the H-type paddle blade installed at the upper stage of the wide paddle blade functions as the auxiliary blade.
The wide paddle blade, which is the main wing, generates a large circulating flow in the vertical direction across the entire stirring tank. When a wide paddle blade rotates in a fluid, a positive pressure is always generated on the surface on the front side and a negative pressure is generated on the back surface with respect to the direction of rotation. On the surface on the front side of the wide paddle blade, the fluid is pushed out in the direction of rotation of the blade and discharged toward the wall surface of the stirring tank due to the influence of centrifugal force. Furthermore, the fluid is pushed out in the vertical direction due to the positive pressure generated on the front surface of the blade, thereby causing the fluid to circulate from the upper and lower ends of the blade toward the negative pressure portion on the back side of the blade. At this time, since the wide paddle blade is installed so as to be in sliding contact with the bottom wall surface of the agitation tank, the flow of fluid from the blade lower end to the blade back side is less than the fluid wrap from the blade upper end to the blade back side.
In the negative pressure portion on the back surface of the blade, in addition to the flow of fluid from the upper and lower ends of the blade, fluid is drawn into the negative pressure portion in the vicinity of the back surface of the blade from the rear in the rotation direction. The fluid drawn toward the upper end, the lower end, and the negative pressure part behind the blades joins in the vicinity of the back surface of the blades and is discharged toward the wall surface of the stirring tank by the action of centrifugal force.

  That is, most of the discharge flow generated by the wide paddle blades installed at the bottom of the tank is created by the negative pressure on the back side of the blades. In addition, the horizontal swirling flow of the fluid caused by the rotation of the wide paddle blade is not caused by the blade pushing the fluid in the rotation direction. It can be considered that it is caused by pulling into the department. Furthermore, even if attention is paid only to the negative pressure portion on the back side of the wide paddle blade, it is considered that a pressure gradient is generated there. That is, it can be said that the negative pressure is closer to the vicinity of the blade tip near the stirring shaft and the blade tip. Therefore, it is considered that the merging of the flow in the negative pressure part accompanying the wraparound and drawing of the fluid is most dense near the blade tip. For this reason, in order to cause more fluid to flow into the tip part on the back side of the blade and efficiently generate the flow merge, a recess is provided near the axis of the upper end of the wide paddle blade to increase the flow of fluid from the upper end of the blade Is particularly preferred.

  Expressing the state where many flows are combined in terms of `` dense streamlines '', a large flow (mainstream in the case of a river) is created by the combination of many flows when the streamlines are dense. And this flow forms a circulation flow over the entire stirring tank.

As described above, the direction of the main flow is influenced by the fact that the fluid wraps around from the upper end of the blade more than the wrap around from the lower end, and is slightly downward from the horizontal in the stirring tank wall surface direction.
Most of the fluid discharged from the tip of the blade is converted into an upward flow along the wall surface in the vicinity of the stirring tank wall surface and rises to the vicinity of the liquid surface along the wall surface. Near the liquid level, the fluid changes its direction of flow toward the center of the stirring tank and is converted into a downward flow due to the influence of the vortex generated near the stirring shaft.

  The H-type paddle wing as an auxiliary wing plays a role of guiding more fluid to the negative pressure part on the back side of the wide paddle wing which is the main wing. Similarly to the wide paddle blade, the H-type paddle blade generates a positive pressure on the front surface in the rotational direction and a negative pressure on the back surface. Therefore, fluid wraps around from the front surface to the back surface of the H-type paddle blade adjacent to the wide paddle blade. Due to this wraparound effect, the fluid in the vicinity of the lower end of the blade is lifted to the back side of the blade of the H-type paddle blade in front of the rotation direction of the H-type paddle blade.

In the stirring device according to the present invention, the H-type paddle blade adjacent to the wide paddle blade of the main wing has an overlap of 1% or more, particularly 5% or more with respect to the height h in the stirring axis direction of the wide paddle blade in the vertical direction. Preferably, the fluid that has flowed around the blade back side at the lower end of the H-type paddle blade can be merged with the flow of wrap around generated at the upper end of the wide paddle blade (see FIG. 7).
Of course, in order to join the wraparound flow, the effect of reducing the overlap until the flow path is blocked is reduced, so it is preferable that the range be 50% or less, particularly 40% or less.

  The overlap between the H-type paddle blade and the wide paddle blade is based on the uppermost end of the wide paddle blade. Since there is a concave portion at the center of the upper end of the wide paddle wing, in practice, the overlap between the H-type paddle wing and the wide paddle wing has a substantially triangular or trapezoidal shape (see FIG. 8). In this way, the overlap is thin near the shaft and thick at a distance from the shaft, so that the wraparound flow created by the H-shaped blade and the wide paddle blade is inclined downward, and the downward flow can be efficiently guided to the main flow ( (See FIG. 8A).

  When the H-type paddle blade has a small blade diameter (blade span) and fluid wraparound occurs in a portion that is relatively close to the agitation shaft, the flow should be merged into a region where the streamline is rough (upstream region, for example, a river). (See FIG. 8A).

  In this case, the fluid lifted to the back side of the lower end of the H-shaped blade is dropped into the negative pressure part on the back side of the wide paddle blade. That is, when the blade diameter of the H-type paddle blade is small, it acts to strengthen the downward flow near the stirring shaft. In addition, the wraparound flow at the lower end of the H-type paddle blade that merges with the wraparound flow at the upper end of the main wing moves toward the stirring tank wall surface on the back side of the main wing, and joins the discharge flow (main flow) generated on the back side of the main wing. In particular, the discharge flow (main flow) of the wide paddle wing, which is the main wing, is also strengthened.

  It is particularly preferable to form a recess at the center of the upper end of the wide paddle blade in order to efficiently generate a merge with the wraparound flow. Similarly, when the H-type paddle blade has a large blade diameter (blade span) and the fluid wraps around a relatively distant from the stirring shaft, the wrap-around flow at the lower end of the H-type paddle blade is They can be merged (see FIG. 8B).

  In this case, since the sneak flow generated at the lower end of the H-type paddle blade is merged with the part where the streamline on the back side of the main wing is dense (main flow), the sneak flow at the lower end of the H-type paddle blade is converted into a downward flow. Immediately after being converted to a discharge flow.

  For this reason, when the blade diameter of the H-shaped blade is large, the discharge flow of the main blade is strengthened, but the effect of strengthening the downflow near the shaft is hardly expected. For example, in the portal wing described in Japanese Patent Application Laid-Open No. 4-90839, the portal wing and the wing installed at the bottom of the tank have substantially the same diameter (same span), and therefore the action of strengthening the downward flow (axial flow) Cannot be obtained. On the other hand, in the present invention, since the H-type paddle blade is designed to have a smaller span than the wide paddle blade, the downward flow (axial flow) can be strengthened.

Further, the H-type paddle blade has an action of preventing the powder from adhering to the stirring shaft.
When only the wide paddle blade is used without installing the H-type paddle blade, the powder put into the stirring tank while stirring the high-viscosity fluid is in close contact with the stirring shaft along the stirring shaft from the fluid surface Is drawn into the liquid.

  On the other hand, when an H-type paddle blade is installed, the powder drawn into the liquid receives the attractive force of the negative pressure part due to the negative pressure generated on the back of the vertically long blade extending in the vertical direction of the blade tip. Since the spiral is drawn and drawn to the vicinity of the upper end of the wide paddle blade that is the main wing (see FIG. 6), there is an effect of preventing the powder from adhering to the stirring shaft.

EXAMPLES Hereinafter, although this invention is demonstrated in more detail using an Example, this invention is not limited to the range of these Examples. In Examples and Comparative Examples shown below, “part” or “%” is based on weight unless otherwise specified.
The latex polymerization used for comparison was tested according to the procedure described below, and was compared with the apparatus of the present invention by changing the stirrer and set rotational speed used at that time.

  Experiment 1: In a pressure-resistant polymerization vessel equipped with a stirrer (l / d = 1.6), 120 parts of water, 0.1 part of sodium hydroxide, emulsifier Newcol 271S (sodium alkyldiphenyl ether disulfonate) [manufactured by Nippon Emulsifier Co., Ltd.] After adding 1.8 parts, sodium ethylenediaminetetraacetate 0.1 parts, styrene 69 parts, acrylic acid 3.0 parts, and t-dodecyl mercaptan 0.7 parts, and replacing with nitrogen, 28 parts of butadiene was injected and stirred. When the temperature in the polymerization vessel reached 60 ° C., 0.4 part of ammonium persulfate was added to start the reaction. When the polymerization rate reached 98%, the temperature was raised to 80 ° C., the reaction was performed for 8 hours, and cooling was performed at a polymerization rate of 99.5%. Subsequently, the pH of the latex was adjusted to 8.5 with 25% aqueous ammonia to obtain SBR latex (i) having a solid content of 45.2%. The stirring power was 0.1 kW / cubic meter throughout the polymerization.

Example 1-A when the stirrer described in the present invention was used in Experiment 1, Comparative Example 1-A when the Max blend blade was used, Comparative Example 1-B when the anchor blade was used, Large anchor The case where a blade is used is referred to as Comparative Example 1-C, and the case where a turbine blade is used is referred to as Comparative Example 1-D.
Experiment 2: In a pressure-resistant polymerization vessel equipped with a stirrer (l / d = 1.6), 120 parts of water, 0.1 part of sodium hydroxide, emulsifier Newcol 271S (sodium alkyldiphenyl ether disulfonate) [manufactured by Nippon Emulsifier Co., Ltd.] After adding 1.8 parts, sodium ethylenediaminetetraacetate 0.1 parts, styrene 69 parts, acrylic acid 3.0 parts, and t-dodecyl mercaptan 0.7 parts, and replacing with nitrogen, 28 parts of butadiene was injected and stirred. When the temperature in the polymerization vessel reached 60 ° C., 0.4 part of ammonium persulfate was added to start the reaction. When the polymerization rate reached 98%, the temperature was raised to 80 ° C., the reaction was performed for 8 hours, and cooling was performed at a polymerization rate of 99.5%. Subsequently, the pH of the latex was adjusted to 8.5 with 25% aqueous ammonia to obtain an SBR latex (ii) having a solid content of 45.2%. The stirring power was 0.04 kW / cubic meter throughout the polymerization.

  Example 2-A when the stirrer described in the present invention was used in Experiment 2, Comparative Example 2-A when the Max blend blade was used, Comparative Example 3-B when the anchor blade was used, Large anchor The case where a blade is used is referred to as Comparative Example 3-C, and the case where a turbine blade is used is referred to as Comparative Example 3-D.

  Experiment 3: In a pressure-resistant polymerization vessel equipped with a stirrer (l / d = 2.2), 120 parts of water, 0.1 part of sodium hydroxide, emulsifier Newcol 271S (sodium alkyldiphenyl ether disulfonate) [manufactured by Nippon Emulsifier Co., Ltd.] After adding 1.8 parts, sodium ethylenediaminetetraacetate 0.1 parts, styrene 69 parts, acrylic acid 3.0 parts, and t-dodecyl mercaptan 0.7 parts, and replacing with nitrogen, 28 parts of butadiene was injected and stirred. When the temperature in the polymerization vessel reached 60 ° C., 0.4 part of ammonium persulfate was added to start the reaction. When the polymerization rate reached 98%, the temperature was raised to 80 ° C., the reaction was performed for 8 hours, and cooling was performed at a polymerization rate of 99.5%. Subsequently, the pH of the latex was adjusted to 8.5 with 25% aqueous ammonia to obtain SBR latex (iii) having a solid content of 45.2%. The stirring power was 0.1 kW / cubic meter throughout the polymerization.

Example 3A using the stirrer described in the present invention in Experiment 3, Comparative Example 3-A using Maxblend blades, Comparative Example 3-B using anchor blades, Large anchor The case where a blade is used is referred to as Comparative Example 3-C, and the case where a turbine blade is used is referred to as Comparative Example 3-D.
For the measurement of the number of coarse particles, the latex (i) after the polymerization was passed through a 325 mesh wire net and a particle size measuring device (COULTER MULTISIZER) manufactured by Coulter Co. was used to obtain the weight% of particles of 2 μm or more.

The results are shown in Tables 1-3. In each table, it was confirmed that the Examples had the smallest amount of coarse particles and the least CG.

The schematic diagram which shows one Embodiment of the stirring apparatus of this invention. The schematic diagram which shows other embodiment of the stirring apparatus of this invention. The schematic diagram which shows other embodiment of the stirring apparatus of this invention. The schematic diagram which shows other embodiment of the stirring apparatus of this invention. The combination example of the H type paddle blade and wide paddle blade used for the stirring apparatus of this invention. In the stirring apparatus of this invention, the conceptual diagram which looked at the flow of the fluid between an H type paddle blade and a wide paddle blade from the side. In the stirring apparatus of this invention, the conceptual diagram which looked at the flow of the fluid between an H type paddle blade and a wide paddle blade from the front.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stirring tank 2 Stirring shaft 3 Wide paddle blade 4 H-type paddle blade 4'H-type paddle blade 5 Rectification means

Claims (2)

A stirring shaft is provided in the central part of the vertical cylindrical stirring tank, a wide paddle blade is disposed on the stirring shaft so as to be close to the bottom of the tank, and one or more stages are provided on the stirring shaft above the wide paddle blade. An H-type paddle blade is disposed, the H-type paddle blade is preceded by a crossing angle of 0.1 to 90 ° with respect to the lower stirring blade vertically adjacent to the rotation direction, and the upper and lower adjacent stirring blades perform stirring with a stirring device, characterized in that which gave overlapping part, a Lula tex method for producing cause polymerization reaction,
The stirring device is
(1) A wide paddle blade having a recess at the center of the upper end is disposed on the stirring shaft so as to be close to the bottom of the tank,
(2) The wide paddle blade diameter ratio with respect to the stirring tank inner diameter is in the range of 0.6 to 0.8;
(3) An H-type paddle blade is disposed on the stirring shaft above the wide paddle blade,
(4) The blade diameter of the H-type paddle blade is in the range of 1/3 to 3/4 of the blade diameter of the wide paddle blade.
(5) The H-type paddle blade is preceded by a crossing angle of 30 to 60 degrees with respect to the rotation direction than the wide paddle blade,
(6) The H-type paddle blade and the wide paddle blade have an overlap of 1% to 50% with respect to the height in the stirring axis direction of the wide paddle blade,
(7) The degree of overlap between the H-type paddle blade and the wide paddle blade is such that the vicinity of the stirring shaft is thin and thick at a distance from the stirring shaft,
(8) The method for producing latex , wherein the length of the H-type paddle blade in the vertical direction is in the range of 1/2 to 4 of the blade diameter of the H-type paddle blade . The method for producing latex according to claim 1, wherein a stirring device having a shape in which a tip portion of the wide paddle blade installed at the lowest stage is retreated with respect to the rotation direction is used.

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