JP3411070B2 - Method for producing polymer powder - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel method for producing a polymer powder. More specifically, the present invention is a spherical polymer powder in which the polymer latex is continuously coagulated to have excellent powder properties represented by blocking resistance, fluidity and bulk specific gravity, and the particle size is uniform. The present invention relates to a method for efficiently producing

[0002]

2. Description of the Related Art In the resin industry, as a method of coagulating a polymer latex to obtain a polymer powder, a polymer latex and an aqueous electrolyte solution are added in a batch or continuously with stirring. , Stirring and mixing the both to obtain a solidified slurry, and further subjecting the slurry to post-treatment, dehydration,
The drying method is often used. As an example, in Japanese Patent Publication No. 3-51728, a graft copolymer obtained by polymerizing a hard polymer-forming monomer such as styrene, methyl methacrylate, acrylonitrile in a latex of a rubber-like polymer such as polybutadiene. A method for producing a rubber-containing graft polymer, which comprises depositing a graft copolymer as substantially spherical particles by slowly coagulating a polymer latex by contacting it with an aqueous electrolyte solution, is proposed. ing. However, this method has drawbacks such that it takes time to form particles, the obtained particles have a wide particle size distribution, and the water content of the particles after dehydration is high. Further, in Japanese Patent Publication No. 3-65376, a polymer latex is characterized in that a latex coagulation nozzle using a specific thin tube is used, and the polymer latex is discharged into a coagulating liquid to coagulate the polymer latex. Is proposed. However, in this method, the discharged polymer latex comes into contact with the coagulation liquid and coagulates in a thread shape, so that the coagulation efficiency is poor and the coagulation nozzle may be clogged, which is satisfactory in terms of productivity. It wasn't good enough. In addition, labor saving is being promoted by automation of powder weighing, large-scale transportation, etc.
(1) Blocking occurs during transportation and storage, and the powder solidifies, which does not affect automatic weighing and transportation. (2) Since the bulk specific gravity of the powder is low, the volume per unit weight is large and the storage area is increased. Problems such as many needs have been closed up. As a countermeasure for this, there is a method of improving the powder characteristics by adding an additive such as a dusting agent, but the effect was not always sufficient.

[0003]

DISCLOSURE OF THE INVENTION The present invention overcomes the disadvantages of the conventional latex coagulation method and continuously coagulates the polymer latex to obtain a powder represented by blocking resistance, fluidity and bulk specific gravity. The object of the present invention is to provide a method for efficiently producing a spherical polymer powder having excellent body characteristics and a uniform particle size.

[0004]

Means for Solving the Problems As a result of intensive studies for achieving the above-mentioned object, the present inventors have found that when polymer latex is continuously solidified to produce polymer powder, Reynolds number is 2100. By adding a pressurized fluid to the following polymer latex flow to make the strain rate of the polymer latex 50 to 5000 sec ^−1, and then continuously adding an aqueous electrolyte solution to the polymer latex. , The polymer latex can be continuously coagulated by promoting the mixing and dispersion of the two in a state where the respective solid contents are high, and as a result, the polymer latex is granular and has a uniform particle size, and has excellent powder characteristics. It has been found that a coalesced powder can be easily obtained. The present invention has been completed based on such findings. That is, according to the present invention, when the polymer latex is continuously coagulated to produce a polymer powder, the pressurized fluid is cyclone-like in the flow path of the polymer latex having a Reynolds number of 2100 or less, or the pressurized fluid is a tube. The strain rate of the polymer latex is 5 by adding it through the slit provided in the passage.
The present invention provides a method for producing a polymer powder, which comprises setting it to ⁰ to 5000 sec ^-1, and then adding an aqueous electrolyte solution to the polymer latex to coagulate it.

The present invention will be described in detail below. In the method for producing the polymer powder of the present invention, the Reynolds number is 210
After adding a pressurized fluid to the polymer latex flow of 0 or less to adjust the strain rate to 50 to 5000 sec ^-1 ,
It is necessary to add an aqueous electrolyte solution to the polymer latex. If the Reynolds number exceeds 2100, the flow of the polymer latex is disturbed, so that the coagulated particles are not spherical and the coagulated particles tend to clog the conduit. Here, the Reynolds-Les number Re is calculated by the formula Re = d ·
u · ρ / μ (where d is the conduit diameter [m], u is the linear velocity of the polymer latex [m / sec], ρ is the density of the polymer latex [kg / m ³ ], and μ is the polymer latex. The viscosity is [kg / m · sec]). Note that ρ and μ are determined by the type of polymer latex. Further, the linear velocity of the polymer latex flowing in the pipeline is highest in the central portion of the pipeline. In the method of the present invention, a linear velocity distribution in the radial direction of the polymer latex is obtained by adding a pressurized fluid to the polymer latex flowing in the conduit under the above conditions.
That is, the pressure gradient is forcibly changed. The degree of change in the linear velocity distribution is represented by a later-described Shear Rate.

In the method of the present invention, polymer latex or water is used as the pressurized fluid. These may be used alone or in combination. When used in combination, the ratio of the polymer latex and water used is not particularly limited. The strain rate referred to in the present invention can be changed along with the flow property by changing the shape of the conduit and the addition method of the pressurized fluid. In the present invention, it is necessary that the thinning rate e of the polymer latex be in the range of 50 to 5000 sec ^-1 . This strain rate e is the linear velocity of the pressurized fluid (in the case of adding both water and polymer latex, the linear velocity of the component having the larger inflow capacity) a ₁ [m
/ Sec] and linear velocity of polymer latex a ₂ [m / sec]
Therefore, it can be obtained by the equation e = (a ₁ −a ₂ ) / d. Here, a ₁ is a value obtained by dividing the flow rate [liter / min] of the pressurized fluid by the area of the addition portion (for example, slit), and a ₂ is the flow rate [liter / min] of the polymer latex in the pipeline. It is the value divided by the cross-sectional area.

When the strain rate is less than 50 sec ^-1 , the dispersion of the aqueous electrolyte solution in the conduit becomes non-uniform, so that a large amount of uncoagulated polymer latex is generated. Meanwhile, 5000 sec ^-1
If it exceeds, the flow of the polymer latex is disturbed, so that the coagulated particles are not spherical, and the pseudo solid particles tend to clog the conduit. In addition, the preferable range of the strain rate is 100 to 3000 sec ^-1 , and the more preferable range is 30.
There is ~ 2000 sec ^-1 . In the method of the present invention, any polymer latex obtained by emulsion polymerization or fine suspension polymerization can be used without particular limitation. As the polymer latex which is particularly preferably used, for example, a rubber-like polymer latex, a latex obtained by graft-polymerizing a monoolefin-based monomer to a rubber-like polymer, and a rubber-forming monomer in a polymer of a monoolefin-based monomer Examples thereof include latex obtained by graft-polymerizing the body. The properties of the latex are not particularly limited, but those having a solid content concentration of 15 to 50% by weight and an average particle size of 0.05 to 1.0 μm are desirable.

[0008] Generally, by graft polymerization, a copolymer having a graft shape is obtained. Preferred examples thereof include a graft copolymer obtained by emulsion-polymerizing a rubber-like polymer as a trunk polymer and a hard polymer-forming monomer as a branch polymer in a latex thereof. . Examples of the rubber-like polymer which becomes a trunk polymer in the graft copolymer or is used as a polymer latex include natural rubber, butadiene rubber, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, isoprene rubber, Examples thereof include natural or synthetic rubber polymers having a glass transition point of −80 to −20 ° C. as a single polymer such as chloroprene rubber, acrylic rubber, and ethylene-vinyl acetate copolymer. These may or may not be crosslinked. Further, in practice, only one kind may be used, or two or more kinds may be used in combination.

On the other hand, examples of the hard polymer-forming monomer constituting the branch polymer of the graft copolymer include (a) aromatic vinyl compounds such as styrene and α-methylstyrene, and (b) methyl methacrylate. , Alkyl methacrylates such as ethylmethacrylate and corresponding acrylic acid alkylesters, (c) vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, (d) vinyl halides such as vinyl chloride and vinyl bromide, etc. Has a glass transition point of 1 as a polymer of
The thing of 00-140 degreeC is mentioned. These monomers may be used alone or in combination of two or more. Further, the hard polymer composed of the monomer,
It may or may not be crosslinked. In addition, as the above (b), an alkyl ester having a carbon number of about 1 to 6 is preferably used. Further, the ratio of the rubber-like polymer to the hard polymer-forming monomer in this graft copolymer is not particularly limited. In the present invention, any aqueous solution of an acid or salt generally used as a coagulant for polymer latex can be used as the aqueous electrolyte solution. Examples of the acid among the coagulants include hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid and the like as inorganic acids,
Examples of the organic acid include acetic acid, tartaric acid and acrylic acid. On the other hand, examples of salts include sulfates represented by aluminum sulfate, inorganic salts such as sodium chloride, calcium chloride and potassium alum, organic salts such as sodium acetate, calcium acetate, potassium formate and calcium formate. To be These may be used alone or in combination of two or more, if desired.

The concentration of the aqueous electrolyte solution in the present invention is appropriately selected depending on the type of the electrolyte and the concentration and type of the polymer latex, but the rubber-like polymer alone or a monoolefin-based monomer is grafted onto the polymer. If it is a polymerized latex, it is usually 1 to 10 in the case of inorganic acid and organic acid.
% By weight, preferably 2-8% by weight, in the case of inorganic and organic salts, usually 1-25% by weight, preferably 5-1
It is 5% by weight. In the present invention, the polymer latex, in advance, a dispersant, a lubricant, a thickener, a surfactant, a plasticizer,
Known additives such as antioxidants, colorants and foaming agents can also be added. As the dispersant, an inorganic dispersant or an organic dispersant which is usually used as a stabilizer for emulsion polymerization or suspension polymerization can be used. Examples of the inorganic dispersant include tribasic calcium phosphate, and examples of the organic dispersant include partially saponified polyvinyl alcohol, cellulose, methyl cellulose, polyalkylene oxide, vinyl imidazole and the like. Further, as the dispersant, an ordinary emulsifier such as an alkylbenzene sulfonate or a fatty acid salt can be used. In the present invention, a polymer latex different from the polymer latex to be coagulated may be added as a pressurized fluid.

In the present invention, the mixing and dispersion of the polymer latex and the aqueous electrolyte solution are promoted by applying the method described below. As the method, (1) a method of adding a pressurized fluid in a cyclone form, (2) a method of adding a pressurized fluid from a slit provided in a conduit through which a polymer latex flows, and a heating fluid with a nozzle Mention may be made of adding pressurized fluid from a supply line.

For example, FIG. 1 illustrates the flow of the pressurized fluid in the case of the above (1), and the reference numeral 1 in the figure is a pressurized fluid supply section.

In the case of (2), there is no particular restriction on the shape of the slit provided in the conduit through which the polymer latex flows, and there is also no particular restriction on the method of adding the pressurized fluid to the conduit. The flow of the pressurized fluid when the pressurized fluid is added in parallel to the conduit is shown in FIG. 2 (a). Further, FIG. 2B shows a flow of the pressurized fluid when the pressurized fluid is added obliquely. FIG. 3 shows a flow of the pressurized fluid in the case of using a slit provided in an annular shape and having a curved ejection port. In this case, the angle θ of the annular slit with respect to the tube axis is in the range of 0 <θ ≦ 90 °, and the ejection port portion is curved so that the Coanda effect can be obtained. An example of the form of the curved surface is shown in FIG. The Coanda effect here refers to the effect that a jet of gas or liquid tries to flow near the direction along the curved surface of the wall even if the jet axis and the curved wall are separated from each other. . Due to this effect, the property of the flow of the polymer latex flowing in the pipe can be changed to a swirling flow or the like.
This is due to the synthesis of the polymer latex stream and the stream of pressurized fluid added to the conduit.

By these methods, a polymer powder having a spherical shape and a uniform particle size and excellent powder characteristics can be easily obtained. An example of the structure of the device used in each method will be described below. The device used in the present invention is not limited to these examples. For example, FIG. 4A is a cross-sectional view showing an example of the structure of the apparatus, in which a slit 7 formed in an annular shape is formed at the end on the thick diameter side of the main cylinder 6 having a portion having a diameter larger than that of the conduit outlet 5. The auxiliary cylinder 8 having the same diameter as the main cylinder 6 equipped with the latex supply pipe 2 is connected through the wall surface 9 of the slit 7 on the main cylinder 6 side, and smoothly bends to the inner wall 10 of the main cylinder. Similarly, the wall surface 11 on the side of the auxiliary cylinder 8 is formed so as to bend and move to the inner wall 12 of the auxiliary cylinder 8, and the end on the opposite side of the main cylinder is gradually narrowed to have a diameter equal to that of the outlet pipe line 5. It is formed in the shape of a cone and is connected to the jet line. The wall surface 11 of the slit 7 on the auxiliary cylinder 8 side is shown in FIG.
It has the structure shown in FIG.

Further, a means (namely, a pressurized fluid supply tube) 3 for supplying a pressurized fluid for causing a swirling flow to the polymer latex in the pipeline is provided outside the slit 7, and an auxiliary cylinder 8 is provided. The aqueous electrolyte solution supply pipe 4 is inserted from the outside along the axis of the main cylinder 6. An apparatus described in JP-A-62-58100 can be used as an apparatus in this method. The diameters of the respective pipes other than the connecting portion of the main cylinder 6 with the outlet pipe 5 are appropriately selected depending on the size of the apparatus itself, the actual production size, and the flow rate of each liquid. The outlet position of the electrolyte aqueous solution supply pipe 4 is not particularly limited, but the same position as the slit 7 is preferable. When the outlet position is close to the latex supply pipe 2, the dispersion of the polymer latex and the electrolyte aqueous solution becomes insufficient, so that the coagulated particles are not spherical and the coagulated particles cause a pipe near the outlet of the electrolyte aqueous solution supply pipe 4. Clogged roads are more likely to occur. Figure 5
It is sectional drawing which shows one example of the structure of another apparatus, Comprising: The rectangular slit 7 is provided at the end of the main cylinder 6 of the same diameter as the conduit outlet 5.
An auxiliary cylinder 8 having the same diameter as the main cylinder 6 equipped with the latex supply pipe 2 is connected via the. Further, a pressurized fluid supply pipe (means for adding pressurized fluid) 3 is provided outside the slit 7, and an electrolyte aqueous solution supply pipe 4 is inserted from the outside of the auxiliary cylinder 8 along the axis of the main cylinder 6. There is. The preferable range of the diameter of each pipe and the preferable position of the electrolyte aqueous solution supply pipe 4 are the same as in the case of FIG. FIG. 6 is a cross-sectional view showing an example of the structure of still another apparatus, in which a latex supply pipe 2 is provided at the end of a main cylinder 6 having the same diameter as the conduit outlet 5 via a slit 7. An auxiliary cylinder 8 having the same diameter as the cylinder 6 is connected,
The wall surface 9 of the slit 7 on the side of the main cylinder 6 smoothly bends and moves to the inner wall 10 of the main cylinder, and the wall surface 11 on the side of the auxiliary cylinder 8 also.
Is bent, and one is formed so as to move to the inner wall 12 of the auxiliary cylinder 8 and the other is oriented with its end facing the inside of the main cylinder. A pressurized fluid supply pipe 3 is provided outside the slit 7, and an electrolyte aqueous solution supply pipe 4 is inserted from the outside of the auxiliary cylinder 8 along the axis of the main cylinder 6. The preferable range of the diameter of each pipe and the preferable position of the electrolyte aqueous solution supply pipe 4 are the same as in the case of FIG.

In the method of the present invention, a pressurized fluid is added to the polymer latex flowing in the conduit to continuously add the aqueous electrolyte solution to the polymer latex having a strain rate within a certain range. The coalesced latex is continuously coagulated to obtain a coagulated slurry. The temperatures of the polymer latex and the pressurized fluid during coagulation are determined by using the minimum film-forming temperature of the latex and the glass transition point of the polymer as a measure. The range is usually 10 to 100 ° C., preferably 2 if it is a rubber-like polymer alone or a latex obtained by graft-polymerizing a monoolefin-based monomer on the polymer.
It is 0 to 70 ° C. The temperature of the aqueous electrolyte solution is not particularly limited. The pH of the polymer latex is
The range in which latex can cause coagulation, that is, 6 to 10
It should be maintained during the period. In the method of the present invention,
The treatment of the slurry may be performed by a known method, but from the viewpoint of the dehydration property of the slurry in the dehydration step, the slurry is neutralized with an alkali such as sodium hydroxide, and 50 to 10
It is desirable to heat-treat at 0 ° C. Dehydration and drying of the slurry after the heat treatment may be carried out by ordinary methods.

According to the method of the present invention, a polymer powder having a spherical shape, a uniform particle size and excellent powder characteristics can be obtained. The mechanism is presumed to be that droplets of the electrolyte aqueous solution form small particles, and the particles take up the surrounding latex to form spherical particles. Examples of the polymer powder obtained by the method of the present invention include various graft copolymers, acrylonitrile-butadiene copolymers, styrene-butadiene copolymers, vinyl chloride resins, methyl methacrylate resins, polystyrene resins and the like. These can be used for all known applications for the respective polymer powders. Preferable examples of the graft copolymer obtained by the method of the present invention include MBS resin (methyl methacrylate-butadiene-styrene copolymer), AB
S (acrylonitrile-butadiene-styrene copolymer), ABSM resin (acrylonitrile-butadiene-
Styrene-methyl methacrylate copolymer), AAS resin (acrylic acid alkyl ester-acrylonitrile-
Styrene copolymer), MAS resin (methyl methacrylate-acrylic acid alkyl ester-styrene copolymer)
And so on. These graft copolymers are used as impact modifiers for general-purpose resins such as vinyl chloride resin, methyl methacrylate resin, and polycarbonate resin with or without additives such as dusting agents. be able to.

[0018]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The latex strain rate and the physical properties of the powder were determined as follows. In addition to this, the state of scale adhesion after continuous operation of each device for about 10 minutes
It was examined visually. (1) Strain Rate (Shear Rate) The linear velocity of each fluid was determined from the flow rate when each fluid was allowed to flow alone, the slit opening area, and the cross-sectional area of the pipe, and from this value was determined by a predetermined calculation. (2) Bulk specific gravity It was determined according to JIS K-6721. (3) Free-flow property After the sample powder was filled in a conical hopper described in JIS K-6721, the lower opening of the hopper was opened, and the number of seconds until the powder completely fell off the hopper was measured. . The smaller the number of seconds, the better the flow of powder. (4) BIN (blocking resistance) This measurement was performed as a measure of the ability to withstand the load during storage.
After filling the hopper of (3) above with sample powder,
The sample powder was supplied from a hopper to a cylinder having an inner diameter of 75 mm and a height of 75 mm. Then on this powder 74.5m in diameter
A disk of m was placed and a weight (load) was gently placed on it. After 1 minute, the disk was removed, and the powder-filled cylinder was slowly laid down to see if the powder collapsed within 1 minute. The above operation is repeated by changing the load on the disk, and the maximum load at which the powder breaks down within 1 minute is BIN
(Block Index). The larger this BIN value, the better the blocking resistance. BIN is 200-300 (g)
Is prone to blocking during transportation and storage,
If it is 0 (g) or more, blocking does not occur and transfer from the receiving hopper and automatic weighing become easy.

Example 1 Graft copolymer obtained by graft-polymerizing a mixture of styrene and methyl methacrylate on a styrene-butadiene copolymer (styrene unit 35% by weight / methyl methacrylate unit 15% by weight / butadiene unit 50% by weight). %), A polymer latex (average particle diameter: 0.1 μm, solid content concentration: 30% by weight) containing 40%) was coagulated using the apparatus shown in FIG. 4 (internal diameter of pipe: 17.5 mm). . First, the polymer latex at 40 ° C. was supplied from the latex supply pipe 2 at a flow rate of 5 l / min. At this time, the Reynolds number of the latex was 300. Next, warm water at 40 ° C. was added from the pressurized fluid supply pipe 3 through an annular slit having a gap of 0.2 mm at a flow rate of 5 liters / minute to cause a swirling flow of the polymer latex in the apparatus. At this time, the linear velocity a ₁ of the hot water at the outlet position of the pressurized fluid supply pipe 3 is 760 cm / sec, the linear velocity a ₂ of the polymer latex in the center of the conduit is 35 cm / sec, and the strain velocity e is 414 sec ^−1. there were. Then, a 30 wt% aluminum sulfate aqueous solution was added from the electrolyte aqueous solution supply pipe 4 at a flow rate of 0.04 liter / min, solidification occurred in the apparatus, and a solidified slurry was continuously obtained from the outlet pipe line 5. It was The obtained slurry was heat-treated at 80 ° C. and further dehydrated and dried to obtain a graft copolymer powder. This powder has a uniform particle size, is spherical, and has a bulk specific gravity of 0.
37 g / ml, free flow for 30 seconds, BI
N was as good as 900 g. Also, after the continuous experiment for about 10 minutes was completed, the inside of the apparatus was inspected, but no scale adhesion was found.

Example 2 The same polymer latex as in Example 1 was coagulated by changing the type of aqueous electrolyte solution. The same device as in Example 1 was used. First, polymer latex at 40 ° C. was supplied from the latex supply pipe 2 at a flow rate of 5 liters / minute.
Next, warm water at 40 ° C. was added from the pressurized fluid supply pipe 3 through an annular slit having a gap of 0.2 mm at a flow rate of 5 liters / minute to cause a swirling flow of the polymer latex in the apparatus. Next, when a 5 wt% concentration sulfuric acid aqueous solution was added from the electrolyte aqueous solution supply pipe 4 at a flow rate of 0.3 l / min, coagulation occurred in the apparatus. A predetermined amount of a 5 wt% sodium hydroxide aqueous solution was added to this coagulated slurry to adjust the pH of the slurry to 6.5, and a coagulated slurry was continuously obtained from the outlet pipe line 5. The obtained slurry was heat-treated at 80 ° C. and further dehydrated and dried to obtain a graft copolymer powder. This powder has a uniform particle size, is spherical, has a bulk specific gravity of 0.39 g / ml, and has a free-flow property of 32.
Seconds and BIN were as good as 900 g.

Example 3 Graft copolymer obtained by graft-polymerizing a mixture of styrene and methyl methacrylate onto a styrene-butadiene copolymer (styrene unit 35% by weight / methyl methacrylate unit 20% by weight / butadiene unit 45% by weight). %), A polymer latex (average particle size: 0.1 μm, solid content concentration: 30% by weight) at a temperature of 60 ° C. was coagulated.
The same device as in Example 1 was used. First, 60
Hot water at ℃ was added from the pressurized fluid supply pipe 3 at a flow rate of 5 liters / minute. Next, the polymer latex at 60 ° C. was supplied from the latex supply pipe 2 at a flow rate of 5 liters / minute, and thereafter treated in the same manner as in Example 1 to obtain a graft copolymer powder. The powder had a uniform particle size and was spherical. The powder characteristics are shown in Table 1.

Example 4 A polymer latex was subjected to coagulation treatment in the same manner as in Example 1 except that a device in which the diameter of the end on the opposite side of the main cylinder was not fitted was used, and a powder of a graft copolymer was obtained. Got The powder had a uniform particle size and was spherical. The powder characteristics are shown in Table 1.

Example 5 The same polymer latex as in Example 1 was coagulated. Figure 5
Using the device (internal diameter of the pipe line: 17.5 mm) shown in FIG. 1, a rectangular slit (0.04 cm) is formed from the pressurized fluid supply pipe 3.
Hot water at 40 ° C. was supplied at a flow rate of 5 liters / minute through the (3.5 cm). The flow of hot water at this time was in the cyclone shape shown in FIG. Next, polymer latex at 40 ° C. was supplied from the latex supply pipe 2 at a flow rate of 5 liters / minute. Then, in the same manner as in Example 1, a 30% by weight aqueous solution of aluminum sulfate was added at a flow rate of 0.04 liters / minute, and thereafter the same treatment as in Example 1 was carried out to obtain a graft copolymer powder. . The powder had a uniform particle size and was spherical. The powder characteristics are shown in Table 1.

Example 6 The same polymer latex as in Example 1 was coagulated. Figure 6
First, the polymer latex at 40 ° C. was supplied from the latex supply pipe 2 at a flow rate of 5 liters / minute using the apparatus shown in (1) (inner diameter of pipe line: 17.5 mm). Next, warm water at 40 ° C. was added from the pressurized fluid supply pipe 3 through the annular slit having a gap of 0.2 mm at a flow rate of 5 liters / min in parallel to the pipe line. At the same time, in the same manner as in Example 1, 30
A weight% aluminum sulfate aqueous solution was added at a flow rate of 0.04 liters / minute, and thereafter the same treatment as in Example 1
A powder of the graft copolymer was obtained. The powder had a uniform particle size and was spherical. The powder characteristics are shown in Table 1.

Comparative Example 1 A polymer latex was coagulated in the same manner as in Example 1 except that the flow rate of water was changed. First, polymer latex at 40 ° C. was supplied from the latex supply pipe 2 at a flow rate of 5 liters / minute. Next, hot water at 40 ° C. is supplied to the pressurized fluid supply pipe 3
Was added at a flow rate of 0.5 l / min through an annular slit having a gap of 0.2 mm. At this time, the strain rate e of the latex was 23.5 sec ^-1 . Then
A 30 wt% aluminum sulfate aqueous solution was added from the electrolyte aqueous solution supply pipe 4 at a flow rate of 0.04 liter / min.
The polymer latex did not coagulate.

Comparative Example 2 A polymer latex was coagulated in the same manner as in Example 1 except that the flow rate of water was changed. First, the polymer latex at 40 ° C. was supplied from the latex supply pipe 2 at a flow rate of 5 liters / minute. Next, warm water of 40 ° C. was added from the pressurized fluid supply pipe 3 through the annular slit having a gap of 0.2 mm at a flow rate of 60 liters / minute. At this time, the strain rate e of the latex was 5180 sec ^-1 . Then, a 30 wt% aluminum sulfate aqueous solution was added from the electrolyte aqueous solution supply pipe 4 at a flow rate of 0.04 l / min, and thereafter, the same treatment as in Example 1 was carried out to obtain a powder of a graft copolymer. . The shape of this powder was irregular. The powder characteristics are shown in Table 1.

Comparative Example 3 The polymer latex was coagulated in the same manner as in Example 1 except that the flow rate of the polymer latex was changed. First, 4
The polymer latex at 0 ° C. was supplied from the latex supply pipe 2 at a flow rate of 40 liters / minute. At this time, the Reynolds number of the latex was 2,400. Next, 40 ℃
The warm water of 1 was added from the pressurized fluid supply pipe 3 through an annular slit having a gap of 0.2 mm at a flow rate of 5 l / min. At this time, the strain rate e of the polymer latex is 354.
It was sec ^-1 . Next, from the electrolyte aqueous solution supply pipe 4, 3
A 0% by weight aqueous solution of aluminum sulfate was added at a flow rate of 0.04 liter / min, and thereafter the same treatment as in Example 1 was carried out to obtain a powder of a graft copolymer. The shape of this powder was irregular. The powder characteristics are shown in Table 1.

Comparative Example 4 The same polymer latex at 40 ° C. as in Example 1 was supplied to a stirring coagulation tank (volume: 10 liters) at a flow rate of 5 liters / minute, and at the same time, a 1.15% by weight aluminum sulfate aqueous solution. (40 ° C.) was added into the coagulation tank at a flow rate of 5.2 l / min to continuously coagulate. Next, the slurry continuously discharged from the coagulation tank was heat-treated at 80 ° C., dehydrated and dried to obtain a powder of a graft copolymer. The shape of this powder was irregular. The powder characteristics are shown in Table 1.

Comparative Example 5 The same polymer latex at 60 ° C. as in Example 3 was fed at a flow rate of 5 liters / minute to a stirring coagulation tank (volume: 10 liters), and at the same time, a 1.15% by weight aqueous solution of aluminum sulfate was used. (40 ° C.) was added into the coagulation tank at a flow rate of 5.2 liters / minute, and thereafter the same treatment as in Comparative Example 4 was performed to obtain a graft copolymer powder. The shape of this powder was irregular. The powder characteristics are shown in Table 1.

[0030]

[Table 1]

Example 7 Graft copolymer obtained by graft-polymerizing a mixture of styrene and methyl methacrylate to a copolymer of butyl acrylate and 2-ethylhexyl acrylate (styrene unit 10% by weight / methyl methacrylate unit). 15% by weight / 35% by weight of butyl acrylate unit) Acrylic acid 2
-Ethylhexyl unit 40% by weight), temperature 40 ° C
Of the polymer latex (average particle diameter 0.1 μm, solid content concentration 30% by weight) shown in FIG. 4 (inner diameter of pipe: 17.
5 mm) for coagulation treatment to obtain a graft copolymer powder. The coagulation treatment was performed in the same manner as in Example 1. This powder has a uniform particle size, is spherical, and has a bulk specific gravity of 0.35 g.
/ Ml, free flow is 35 seconds, BIN is 9
It was as good as 00 g. After the continuous experiment for about 10 minutes was completed, the inside of the apparatus was inspected, but no scale adhesion was found.

Example 8 A polymer latex was subjected to coagulation treatment in the same manner as in Example 7 except that an apparatus in which the diameter of the end on the opposite side of the main cylinder was not fitted was used, and a powder of a graft copolymer was obtained. Got The powder had a uniform particle size and was spherical. The powder characteristics are shown in Table 2.

Comparative Example 6 The same polymer latex at 40 ° C. as in Example 7 was fed into a coagulation tank (volume: 10 liters) under stirring at a flow rate of 5 liters / minute, and at the same time, a 1.15% by weight aluminum sulfate aqueous solution. (40 ° C.) was added into the coagulation tank at a flow rate of 5.2 liters / minute, and thereafter the same treatment as in Comparative Example 4 was performed to obtain a graft copolymer powder. The shape of this powder was irregular. The powder characteristics are shown in Table 2.

[0034]

[Table 2]

[0035]

According to the present invention, when a polymer latex is continuously coagulated to produce a polymer powder, a pressurized fluid is added to a stream of the polymer latex having a Reynold's number of 2100 or less to obtain a strain rate. To 50 to 5000 sec ⁻¹ and continuously adding an aqueous electrolyte solution to the polymer latex, the mixing and dispersion of the polymer latex and the aqueous electrolyte solution are promoted, and the polymer latex and the aqueous electrolyte solution are continuously added at a high concentration. Can coagulate polymer latex,
A polymer powder having a spherical shape and excellent powder characteristics and a uniform particle size can be easily obtained. The polymer powder obtained by the method of the present invention is excellent in powder characteristics as compared with the powder obtained by the coagulation treatment in the conventional coagulation tank, and thus is unlikely to cause blocking during transportation and storage Easy to measure and transport, high bulk specific gravity saves a small storage area, uniform particle size reduces the load in the dehydration process, and prevents dust from deteriorating the working environment. It is effective in that it is not always necessary to use an additive such as a dusting agent in order to improve body characteristics.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an example of a method of the present invention.

FIG. 2 is a conceptual diagram showing different examples (a) and (b) of the method of the present invention.

FIG. 3 is a conceptual diagram showing an example of the method of the present invention.

FIG. 4 (a) is a sectional view showing an example of the structure of an apparatus for carrying out the method of the present invention. (B) is an enlarged view of a wall surface of the slit of the apparatus on the auxiliary cylinder side.

FIG. 5: Structure 1 of a device for carrying out the method of the invention
It is sectional drawing which shows an example.

FIG. 6 shows one of the structures of the apparatus for carrying out the method of the present invention.
It is sectional drawing which shows an example.

[Explanation of symbols]

1 Pressurized fluid supply unit 2 Latex supply pipe 3 Pressurized fluid supply unit 4 Electrolyte solution supply pipe 5 pipelines 6 main cylinder 7 slits 8 auxiliary cylinders 9 Slit main cylinder side wall surface 10 Inner wall of main cylinder 11 Side wall surface of the slit auxiliary cylinder 12 Inner wall of auxiliary cylinder

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshihiko Hori 1-2-1, Yokou, Kawasaki-ku, Kawasaki-shi, Kanagawa, Japan Research & Development Center, Zeon Corporation (72) Kouji Kato, Yakou, Kawasaki-ku, Kawasaki-shi, Kanagawa 1-2-1 Nihon Zeon Co., Ltd. Research and Development Center (72) Inventor Makoto Yamamoto 1-2-1 Yokou, Kawasaki-ku, Kawasaki-shi, Kanagawa Nihon Zeon Co., Ltd. Kawasaki Plant (56) References 56-18602 (JP, A) JP 63-264636 (JP, A) JP 58-80328 (JP, A) JP 60-15407 (JP, A) JP 60-124627 (JP, A) A) JP-A-57-187322 (JP, A) JP-A-51-107340 (JP, A) JP-A-62-227707 (JP, A) JP-A-3-119030 (JP, A) (58) Survey the field (Int.Cl. ^7, B name) C08J 3/00 - 3/28

Claims (2)

(57) [Claims] 1. When continuously polymerizing a polymer latex to produce a polymer powder, a pressurized fluid is added in a cyclone form to the flow of a polymer latex having a Reynolds number of 2100 or less in a cyclone form. Strain rate of combined latex is 5
A method for producing a polymer powder, which comprises setting to ⁰ to 5000 sec ^-1 and then coagulating by adding an aqueous electrolyte solution to the polymer latex. 2. When a polymer latex is continuously coagulated to produce a polymer powder, a pressurized fluid is supplied from a slit provided in the pipeline to the flow of the polymer latex having a Reynolds number of 2100 or less. A method for producing a polymer powder, which comprises adding a polymer latex to a strain rate of 50 to 5000 sec ⁻¹ and then adding an aqueous electrolyte solution to the polymer latex to coagulate it.