JPS6286001A - Production of polymer particle - Google Patents

Abstract

PURPOSE:To obtain polymer particles prevented from association, agglomeration and dissociation in the course of their formation, by rotating a reaction vessel filled with a medium containing a monomer about an axis kept in such a position as to form a specified angle with the horizontal plane. CONSTITUTION:A sealed cylindrical reaction vessel 1 is charged with a medium 3 containing a monomer so that its inside space may be completely filled this with. The axis X of the reaction vessel 1 is kept in such a position as to form an angle in the range of 0-60 deg. with respect to the horizontal plane, and the reaction vessel 1 is rotated around this axis X at a constant rotation speed by a driving mechanism. By rotating the reaction vessel 1 around this axis, the mixture system of the medium 3 with the monomer can be allowed to rotate usually steadily around its axis X by the viscosity of the medium 3 while it is kept in a state in which the mixture moves together with the reaction vessel and so undergoes no mechanical flow. The rotation speed is increased if the precipitation of the formed polymer particles occurs when polymer particles are formed by performing the polymerization of the monomer in the medium in the above state.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for producing polymer particles.

[Conventional technology]

Conventionally, methods for producing polymer particles include emulsion polymerization,
Methods such as a suspension polymerization method, a solution/tR polymerization method, a method of precipitating polymer particles from a polymer solution, and a polymer redispersion method are known. In the production of polymer particles by these methods, the system is usually stirred with a rotary blade in order to prevent coalescence, aggregation, or splitting of the polymer particles during the monomer dispersion and production process. However, with this method, it is difficult to sufficiently suppress coalescence, aggregation, or splitting of particles during the production process of polymer particles. As a result, the particle size of the resulting polymer particles was non-uniform, and the particle size distribution was wide.

Therefore, various methods have been proposed to produce uniform polymer particles with a narrow particle size distribution. One of these methods is, for example, a method in which polymerization is carried out in a system in which a medium flows in a laminar flow state in a pipe. It is being However, with this method, collisions between polymer particles are unavoidable due to friction between the medium and the inner wall of the pipe, and it is not always sufficient to prevent polymer particles from coalescing, agglomerating, or splitting. If this point is to be sufficiently improved, large-scale equipment will be required, and high productivity will be difficult to obtain.

[Problem that the invention seeks to solve]

The present invention solves the problems of the prior art as described above, and promotes the dispersion or dissolution of monomers in a medium and the coalescence of polymer particles during the production process.

The purpose is to prevent agglomeration or fragmentation.

[Means for solving problems]

The above problem is caused by the fact that the reaction vessel filled with the mixed system containing the 7-mer in the medium is placed at an angle of 0.
Polymerizing the hexamer in the mixture system and dispersing the polymer particles in the medium by rotating the mixture system together with the reaction vessel by rotating it around an axis held at an angle in the range of 60°. The problem is solved by a method for producing polymer particles, which is characterized by comprising a step of producing polymer particles in a state in which they are produced.

Next, the main points of the present invention will be conceptually explained.

In the present invention, as shown in FIGS. 1 and 2,
For example, a cylindrical sealed reaction vessel 1 is filled with a medium 3 containing a monomer so that the internal space of the reaction vessel 1 is substantially filled, and the axis X of the reaction vessel 1 is set at 0 to 6
0°, preferably 0-45″, particularly preferably 0-5°
The reaction vessel 1 is rotated around this axis X at a constant rotational speed by a drive mechanism (not shown) while maintaining the angle within the range of . By rotating the reaction container 1, the mixed system of the medium 3 and the monomer inside the reaction container 1 is rotated around the axis X, normally in a steady state, in a so-called integral manner with the reaction container 1, without mechanical flow, due to the viscosity of the medium 3. Rotate the target. In this state, the monomer in the medium 3 is polymerized to produce polymer particles, and if sedimentation of the produced polymer particles is observed, the rotation speed is increased.

Furthermore, in the present invention, a buffer device (not shown) can be installed to adjust the pressure inside the reaction container to a constant level, if necessary.

In this way, the polymer particles generated in the mixing system that rotates with the reaction vessel change their position relative to the outside of the reaction vessel without changing their relative position in the medium due to the viscosity of the medium. It is possible to create a state in which gravity acts from different directions, and such a state can be achieved by appropriately selecting the specific gravity and size of the polymer particles, the specific gravity and viscosity of the medium, the rotation speed of the reaction vessel, etc. It can be realized.

In such a state, when looking at the polymer particles (indicated by reference numeral 2 in FIG. 3) in the mixed system, one polymer particle 2 is absorbed into the medium 3 as schematically shown in FIG.
Within the medium 3, the medium 3 moves relatively slowly in a circular motion as shown by arrow A in a state where there is no mechanical flow. In addition, such local circular motion occurs uniformly in each polymer particle in a nearly approximate state, so collisions between polymer particles are almost avoided, or polymer particles are Even if collisions occur, the impact force does not cause the particles to coalesce or aggregate, and the polymer particles are uniformly dispersed as single particles in the medium. This is considered to be the case.

The production method of the present invention can be applied to a type of polymerization in which a polymer is produced in a particle state in a medium, and can be employed, for example, in emulsion polymerization, suspension polymerization, solution precipitation polymerization, and the like.

Therefore, the mode of the reaction system filled in the reaction vessel, such as the medium and monomer, is selected depending on the polymerization form to be employed. For example, when the present invention is applied to emulsion polymerization or suspension polymerization, the monomers are dispersed in a medium (dispersion medium) to form an emulsion or suspension, and the dispersed monomers are in the form of the aforementioned polymer particles. It is uniformly dispersed in a dispersion medium in the same state as above, and polymer particles are generated as the polymerization progresses. Further, in emulsion polymerization, if no emulsifier is used or if an emulsifier is used but only in a trace amount, the monomer may remain as an oil layer. Furthermore, in the case of solution precipitation polymerization, the hexamer is dissolved in the medium (solvent) and is in a solution state, and as the polymerization progresses, the polymer with lower solubility is precipitated in the form of particles.

In the present invention, the rotation speed of the reaction vessel is generally determined by the polymerization form, the size and specific gravity of the monomer oil droplets, the size and specific gravity of the polymer particles to be produced, the viscosity of the medium, the shape and size of the reaction vessel, etc. Usually 1 to 30r, p, m, preferably 2 to 20
Adjust to the extent of r, p, m.

In the present invention, it is preferable that the mixed system of the medium and the monomer be completely filled in the reaction vessel so that there is no space, thereby ensuring that the mixed system is rotated together with the reaction vessel. It becomes easier. however,
Even if there is a space in the reaction vessel, if it is small, the disturbance in the medium due to the presence of the space will be limited to a small area in the upper part of the mixing system in the reaction vessel, so in effect this This does not invalidate the effect of the invention. However, if the proportion of space within the reaction vessel increases, the mixing system cannot be rotated together with the reaction vessel without disturbing it, making it impossible to achieve the object of the present invention. For this reason, in the present invention, the case where the filling ratio of the mixed system in the reaction vessel is 80% by volume or more is defined as a substantially full state, and the filling ratio is preferably 90% by volume or more, particularly preferably 98% by volume. % or more.

Furthermore, the shape of the reaction container is preferably cylindrical, but there is no problem if it is prismatic or spherical, and the rotation method is essentially rotated in a vertical plane so that the top and bottom of the container are reversed. For example, an arm 11 rotating around a horizontal rotation axis 10 as shown in FIG.
The container 12 may be held at the tip of the container 12 and rotated in a vertical plane, and the cylindrical reaction container 20 may be rotated around a horizontal axis Y extending in the radial direction, as shown in FIG. You can also rotate it.

Next, the present invention will be explained in more detail according to the polymerization form.

(1) Solution precipitation polymerization method The combination of the polymer and polymerization initiator used in the solution precipitation polymerization method is not limited as long as it is soluble in the medium and the resulting polymer is insoluble in the medium. For example, the monomers include styrene monomers such as styrene and chlorostyrene, methyl (meth)acrylate, 〇-phytyl (meth)acrylate, hydroquinethyl (methaneacrylate), glycidyl (meth)acrylate, and (meth)acrylate. ) (meth)acrylic acid ester monomers such as polyoxyethylene acrylate; (meth)acrylonitrile; (meth)acrylamide; (meth)acrolein; vinyl acetate; vinyl halide monomers such as vinyl chloride and vinylidene chloride; ) Unsaturated acid (anhydride) monomers such as acrylic acid, itaconic acid, and maleic acid (anhydride); diene monomers such as butadiene and isoprene; Thermosetting resin prepolymers such as unsaturated polyester resins and epoxy resins can also be used as monomers.If the resulting polymer has relatively high solubility in the solvent, the solubility can be increased by using a polyfunctional monomer in combination. It is preferable to reduce the
Examples include divinylbenzene, triaryl isocyanurate, ethylene glycol di(meth)acrylate,
trimethylolpropane tri(meth)acrylate,
Methylene bisacrylamide, polyoxyethylene di(
Examples include meth)acrylate.

As the polymerization initiator, radical initiators, transition metal complex catalysts, anionic initiators, and cationic initiators are used, but radical initiators are generally used. As a radical initiator, hendyl peroxide, octanoyl peroxide, methyl ethyl ketone peroxide, dicumyl peroxide, not-t-butyl peroxide, t-butyl hydroperoxide,
Hydrogen peroxide, potassium persulfate, ammonium persulfate, azobisisobutyronitrile, and redox catalysts using these, such as benzoyl peroxide and dimethylaniline, hydrogen peroxide and ferrous chloride, potassium persulfate and bicarbonate
Combinations such as Afa sodium are used. The layer of radical polymerization initiator used is usually 0.1 to 5 parts by weight to 100 parts by weight of monomer, which is the same as when using other polymerization equipment.

Note that polymerization may be carried out simply by heating without using these polymerization initiators. The medium is water;
Alcohols such as methanol, ethanol, ethylene glycol, cellosolve, calpitol (trade name); Esters such as ethyl acetate, diethyl acetate n-dibutylphthalate, tricresyl phosphate, γ-butyrolactone, ethyl silicate; acetone, methyl ethyl ketone, acetophenone, etc. ketones; ethers such as dibutyl ether, diphenyl ether, tetrahydrofuran, anisole; hydrocarbons such as n-hexane, n-octane, cyclohexane, tetralin, decalin, benzene, toluene, xylene, liquid paraffin; chlorobenzene, dichlorobenzene, dodecyl halogenated hydrocarbons such as chloride and halogenated paraffin; amides such as formamide, dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; and pyridine, morpholine,
Examples include dimethyl sulfoxide, which can be used in appropriate combination to adjust the solubility of the monomer and polymerization initiator.

Polymer particles with a narrow particle size distribution can be obtained even if the mixing ratio of the seven polymers and the medium is increased to 10/100 to 50/100, which is 2 to 10 times the monomer/medium ratio of the conventional method. Also,
Preferred monomer/medium ratio is 10/100 to 30/10
0, and the larger the monomer/medium ratio, the larger the particle size of the produced polymer tends to be.

In addition, the particle size of the polymer particles produced in the solution precipitation polymerization method to which this production method is applied tends to decrease as the polymerization rate of the monomer and the solubility of the polymer in the solvent decrease, but depending on the combination of monomers, polyfunctional It can be adjusted by adjusting the amount of the reactive monomer used, the combination of solvents, the monomer/vehicle ratio, the type and amount of the polymerization initiator, the polymerization temperature, etc.

(2) Emulsion polymerization method Monomers to which the emulsion polymerization method is applied include (1) above.
Among the monomers exemplified in the solution precipitation polymerization method, the monomers excluding the thermosetting resin prepolymer can be exemplified, but the amount of water-soluble monomers used among the exemplified monomers is about 20% by weight of the total seven polymers. Limited to: Since the medium in the emulsion polymerization method is water, the polymerization initiator is a water-soluble polymerization initiator among the aforementioned polymerization initiators,
For example, potassium persulfate is used.

Emulsifiers used in emulsion polymerization include sodium dodecylhenzenesulfonate, sodium lauryl sulfate, and
lffie! Potassium, polyoxyethylene nonylphenyl ether, etc. per 1 part of 100ffi of monomer,
About 0.1 to 3 parts by weight are used, but when the monomer is water-soluble to some extent, for example, when methyl methacrylate, acrylonitrile, styrene and methacrylic acid are used as monomers, the use of an emulsifier is not necessarily necessary.

υ1 for the entire monomer mixed system in emulsion polymerization method
The amount is usually 2 to 40% by weight. In the emulsion polymerization method, the particle size of the polymer particles produced depends on the polymerization temperature, the concentration of the emulsifier, the combination of seven polymers, the amount of polyfunctional monomer used, the ratio of monomer to water, the type and amount of the polymerization initiator, etc. It can be adjusted by

(3) Suspension polymerization method The monomers, polymerization initiators, and media to which the suspension polymerization method is applied can be the same as those exemplified in the solution precipitation polymerization method (1) above. The combination is limited to combinations in which monomers containing a polymerization initiator are dispersed in the form of droplets in a medium.

Furthermore, the monomer may be dissolved in one medium and dispersed as droplets in another medium (for example, a solution consisting of methacrylic acid, methylene bisacrylamide, potassium persulfate, and water may be dissolved in the medium). Examples include combinations dispersed in paraffin.

In suspension polymerization, the proportion of monomers in the entire mixed system is usually 2 to 40% by weight. In the suspension polymerization method, the particle size of the polymer particles produced is determined by the particle size of the droplets containing the monomer when initially dispersed. In addition, the above (
The polymerization conditions other than those mentioned above in 1) solution precipitation polymerization method (2) emulsion polymerization method and (3) suspension polymerization method are not particularly different from normal polymerization conditions, and commonly used polymerization conditions can be applied. .

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto. In addition, in the following description, "part" and "%" represent parts by weight and weight %.

Example 1 (Solution precipitation polymerization) (Monomers) Methacrylic acid 10 parts Methyl methacrylate 9 parts Ethylene glycol dimethacrylate 1 part (vehicle) Ethyl acetate 50 parts Kurirchenzen 50 parts (polymerization initiator) Benzoyl peroxide 0.6 parts or more of substances, the capacity is 100mj! A cylindrical container was filled with no air layer, and the rotation speed was 6r, p, m.

Polymerization was carried out at 70° C. for 7 hours while rotating the container around a horizontal axis. As a result, the average particle size was 3.5 μm,
Standard deviation of particle size f! of 0.12 μm! F-shaped polymer particles were obtained. The polymerization conversion rate in this polymerization was 92%,
No aggregate formation was observed.

Comparative Example 1 Monomers, medium, and polymerization initiation having the same composition as in Example 1 except that a reaction vessel with a capacity of 300 mβ having an anchor-type stirring blade was used and the system was mechanically stirred at a rotation speed of 100 r, p, n. Polymerization was carried out under similar conditions using the following agents. As a result, the entire product became solid and it was impossible to stir it, so polymerization was carried out by doubling the size of the medium tank, and the average particle size was 1 μm.
Non-spherical polymer particles with a standard deviation of 0.20 μm were obtained. The polymerization conversion rate in this polymerization was 70%, and the production rate of aggregates was 8%.

Example 2 (Emulsion polymerization) (Nanatsumer) Styrene 10 parts (medium) Water 30
(Polymerization initiator) Potassium persulfate 0.05 parts (Emulsifier) Sodium dodecylhenzenesulfonate 0.03 parts or more of the substances are mixed, filled into a cylindrical container with a capacity of 100rni+ without an air layer, and rotated. Speed 13r,p,
m, while rotating the container around a horizontal axis, 70
Polymerization was carried out at ℃ for 12 hours. As a result, the average particle size O08
A latex containing polystyrene particles with a standard deviation of particle size of 0.01 μm was obtained. The polymerization conversion rate in this polymerization was 95%, and the production rate of aggregates was 1.6%.

Comparative Example 2 The same composition of monomers, medium, and polymerization initiation as in Example 2 was used, except that a reaction vessel with a capacity of 300 mρ having an anchor-type stirring blade was used, and the system was mechanically stirred at a rotation speed of 150 r, p, m. Polymerization was carried out under similar conditions using agents and emulsifiers. As a result, the average particle size was 0.34 μm, and the standard deviation was 0.
A latex containing polymer particles of 0.02 μm was obtained. The polymerization conversion rate in this polymerization was 92%, and the production rate of aggregates was 5.
．． It was 4%.

Example 3 (Suspension polymerization) (Monomers) Styrene 20 parts Divinylbenzene 20 parts Toluene (monomer dilution solvent) 20 parts (medium) Polyvinyl alcohol "Gohsenol Gl+20" (manufactured by Nippon Gosei Kagaku ■) 2% aqueous solution 300 parts ( Polymerization initiator) Benzoyl peroxide 1.5 parts or more of the substance was placed in a flask and stirred for 30 minutes at a rotational speed of 300 r, p, m using a stirrer consisting of a flat turbine blade to form a monomer solution with a particle size of approximately 2001 Jm. Liquid, ・Dispersed in 1. Next, this dispersion liquid was filled into a cylindrical container with a volume of 1100 mg without an air layer, and the rotation speed was 10 r, p, m,
Polymerization was carried out at 60° C. for 12 hours while rotating the container around its horizontal axis. After washing the produced polymer particles with water, particles having a particle size in the range of 156 to 254 μm were obtained by sieving. Particle size 156-25 for all produced polymer particles
The yield of polymer particles in the 4 μm range was 56% by volume.

Comparative Example 3 A dispersion of droplets with a particle size of about 200 μm consisting of a seven-mer medium and a polymerization initiator having the same composition as in Example 3 was prepared in Example 3.
Created in the same way. Next, the obtained dispersion was placed in a reaction vessel having a capacity of 300 mff and equipped with an anchor type stirring blade, and polymerization was carried out under the same conditions as in Example 3, except that the dispersion was stirred at a rotational speed of 20 Or, p, m.

After washing the produced polymer particles with water, particles in the range of 156 to 254 μm were sieved and obtained. The yield of polymer particles having a particle size in the range of 156 to 254 μm based on all produced polymer particles was 40% by volume.

〔Effect of the invention〕

In the production method of the present invention, polymerization can be carried out without mechanically stirring the mixed system of the medium and monomer by rotating the reaction vessel around an axis that is at an angle of 20 to 60'' with respect to the horizontal plane. Therefore, it is possible to improve the dispersion of the seven polymer particles in the medium, and also to improve the dispersion of the polymer particles during the production process and after the production.

Furthermore, in the production method of the present invention, as mentioned above, the mixing system is not mechanically stirred, so no shearing force or large impact force is applied to the polymer particles during the production process. Therefore, polymer particles are prevented from colliding with each other and coalescing, aggregating, or splitting.

As described above, according to the present invention, in the solution precipitation polymerization method, emulsion polymerization method, suspension polymerization method, etc. for producing polymer particles, the polymer particles are transferred to the medium during the production process without applying shearing force to the wood. It is possible to provide a production method that can easily obtain uniform polymer particles with a large particle size (and a narrow particle size distribution) with high production efficiency.

[Brief explanation of drawings]

1 and 2 are an explanatory sectional view and a perspective view of an example of the present invention, FIG. 3 is an explanatory diagram of the movement of particles in a medium, and FIGS. 4 and 5 are an explanatory diagram of an example of the present invention, respectively. It is an explanatory sectional view and a perspective view showing an example. 1, 12.20...Reaction container 2...Polymer particles 3...LZ in medium 2 layer 30

Claims (1)

[Claims] 1) A reaction vessel filled with a mixed system containing monomers in a medium so as to be substantially full is rotated around an axis held at an angle in the range of 0 to 60 degrees with respect to a horizontal plane to cause the mixed system to react. A method for producing polymer particles, comprising the step of polymerizing the monomer in the mixing system by rotating it together with a container to produce polymer particles dispersed in the medium.