JPH07292004A - Suspension polymerization method - Google Patents

Abstract

PURPOSE:To obtain polymer beads uniform in particle diameter by effecting the polymerization of a suspension formed by dispersing a polymerizable monomer with the aid of a dispersant in an annular space between an outer stationary cylinder and an inner rotary coaxial cylinder at a revolution speed to give a specified Archimedes number and a specified Taylor number. CONSTITUTION:The polymerization of a suspension formed by dispersing drops of a polymerizable monomer (B) in a continuous phase (A) containing a dispersant in the annular space between an outer stationary cylinder 2 and a inner rotary coaxial cylinder 1. The above polymerization is effected under conditions in which the Taylor number as defined by equation II [wherein Rj is the outside diameter of cylinder 1; omega is the angular revolution speed of cylinder 1; d is the width of the annular space; and nu is the kinematic viscosity) lies in the range: 1.16X10<5> Ar+38.8<=Ta<=2000 for Ar<7X10<-4>; and in the range: 8.12X10<5> Ar-367<=Ta<=2000 for Ar>7X10<-4> (wherein Ar is an Archimedes number as defined by equation I (wherein DELTArho is the difference between the specific gravity of the drop and that of continuous phase (A); Dp is the diameter of a drop; mu is the viscosity of continuous phase A; and g is the gravitational acceleration)]. The above suspension is formed by previously mixing phase A with monomer B in a drop formation apparatus 7. Under above conditions, a Taylor vortex is generated to stabilize the drops, resulting in the formation of beads uniform in particle diameter.

Description

Detailed Description of the Invention

[0001]

This invention relates to a suspension polymerization method. More specifically, the present invention relates to suspension polymerization of a suspension in which a group of polymerizable monomer droplets is dispersed while causing a Taylor vortex in the annular portion of a coaxial double-rotating cylinder having an outer cylinder and an inner cylinder. The present invention relates to a suspension polymerization method by carrying out. The suspension polymerization method of the present invention is useful for obtaining polymer beads with a uniform particle size and a high yield.

[0002]

2. Description of the Related Art A special vortex flow is generated by filling a fluid between two cylinders sharing a central axis, keeping an outer cylinder stationary, and rotating an inner cylinder above a certain critical value. It is known. In such a device, the flow velocity near the inner cylinder is higher than that near the outer cylinder, so that the centrifugal force of the fluid mass rotating near the inner cylinder is greater than the centrifugal force of the fluid mass rotating near the outer cylinder. The fluid mass near the inner cylinder becomes jetted as a discharge flow toward the outer cylinder, and instead, the fluid mass near the outer cylinder flows as a return flow toward the inner cylinder. Since such a discharge flow and a return flow are regularly arranged in the axial direction of the cylinder, a donut-shaped vortex is formed so as to wind the inner cylinder. This vortex is called the Taylor vortex.

A device for producing this Taylor vortex may be any device having a coaxial rotating cylinder structure having a stationary outer cylinder and a rotatable inner cylinder.
There is one disclosed in Japanese Patent Publication No. 56-139122.

A method for producing polymer particles by carrying out suspension polymerization while producing a Taylor vortex is disclosed in JP-A-5-132504. However, in the method disclosed in the above publication, when the difference between the specific gravity of the polymer droplets and the specific gravity of the continuous phase containing the dispersant is large,
Since the effect of buoyancy or gravity on the polymer droplets is stronger than the stirring force due to Taylor vortex, the polymer droplets (dispersed phase) are short-passed in the reactor when conducting the polymerization reaction continuously. Some of the polymer droplets are discharged from the reactor before reaching the target reaction rate,
On the contrary, it is not discharged from the reactor and excessively accumulates in the reactor,
As a result, there is a problem that the flow path is blocked. Further, when performing the batch reaction by the method disclosed in the above publication,
When the specific gravity of the polymer droplets is lower than that of the continuous phase, the polymer droplets float in the upper part of the reactor. Conversely, when the specific gravity of the polymer droplets is higher than that of the continuous phase, the polymer droplets settle at the bottom of the reactor. As a result, polymer droplets are coalesced, resulting in a decrease in yield. Furthermore, the method disclosed in the above publication has a drawback that the obtained polymer beads have a wide particle size distribution.

On the other hand, prior to the polymerization, an oil-in-water type dispersion of a polymerizable monomer having a uniform particle size is produced in another apparatus, and then this dispersion is fed into a polymerization reactor to carry out suspension polymerization. Is being considered. In Japanese Patent Laid-Open No. 57-102905, a polymerizable monomer is jetted through a nozzle, and the jet stream is subjected to mechanical vibration to produce an oil-in-water dispersion of the polymerizable monomer having a uniform particle size. JP-A-3-249931 discloses a method of suspension polymerization of a polymerizable monomer in water having a uniform particle diameter using a nozzle plate in which a large number of ejection holes are annularly arranged. Disclosed is a method of producing an oil-type dispersion and subjecting it to suspension polymerization.

As a result of intensive studies on the method of polymerizing a suspension in which polymerizable monomer droplet groups are dispersed, the inventors have found that polymerizable monomer droplet groups formed through a droplet forming device When suspension polymerization is performed on the dispersed suspension while Taylor vortex is generated in the annular part of the coaxial double rotating cylinder having the outer cylinder and the inner cylinder, the polymerizable monomer droplets react in the reaction system to be handled. The present invention has been completed by finding Taylor number conditions that do not cause a short pass or floating or sinking inside the vessel. An object of the present invention is to provide a suspension polymerization method capable of producing polymer beads having a uniform particle size in high yield.

[0007]

According to the present invention, a suspension in which polymerizable monomer droplets are dispersed in a continuous phase containing a dispersant has a stationary outer cylinder and a rotatable inner cylinder. Archimedean number (Ar
Is 7 × 10 ⁻⁴ or less, the Taylor number (represented by Ta) is 1.16 × 10 ⁵ Ar + 38.8 ≦ Ta ≦ 2000.
When the Archimedes number is larger than 7 × 10 ^-4, polymer beads are produced by polymerizing while rotating the inner cylinder so that the Taylor number is within the range of 8.12 × 10 ⁵ Ar-367 ≦ Ta ≦ 2000. A suspension polymerization method is provided.

The Taylor number defines the generation of Taylor vortices, and is expressed by the following equation: Ta = (Ri.ω.d / ν) (d / Ri) ^1/2 (where Ta is the Taylor number, Ri is the outer diameter of the inner cylinder, ω is the rotational angular velocity of the inner cylinder, d is the width of the annular portion of the inner and outer cylinders, and ν is the kinematic viscosity. That is, the Taylor vortex is determined by each parameter of the outer diameter of the inner cylinder, the rotational angular velocity of the inner cylinder, the width of the annular portion of the inner and outer cylinders, and the kinematic viscosity. The Archimedes number is a dimensionless number that takes into consideration the buoyancy (gravitational force) with respect to a droplet, and the following equation: Ar = (Δρ ² · Dp ³ · g) / μ ² (where Ar is the Archimedes number and Δρ Is the specific gravity difference between the droplet and the continuous phase, Dp is the droplet diameter, μ is the continuous phase viscosity, and g is the gravitational acceleration. From this equation, it is understood that the larger the Archimedes number, that is, the larger the specific gravity difference between the droplet and the continuous phase, the larger the droplet diameter, or the smaller the continuous phase viscosity, the greater the effect of buoyancy or gravity on the droplet. It

Now, the relationship between the Archimedes number and the Taylor number will be described. FIG. 4 shows the Taylor number when the specific gravity of the dispersed phase (droplet) is lighter than that of the continuous phase.
When the suspension polymerization reaction was carried out continuously while holding at 755,
The relationship between the time (t _D ) at which the peak of the residence time distribution of the dispersed phase appears (t _D ) divided by the time (t _C ) at which the peak of the residence time distribution of the continuous phase appears (t _D / t _C ) and the Archimedes number is shown. ing. From Fig. 4, t _D / t _C up to a certain Archimedes number
= 1.0, that is, the dispersed phase flows in the reactor according to the flow of the continuous phase, but when the Archimedes number increases beyond a certain value, the effect of buoyancy on the dispersed phase increases, so t _D / t _C <1.0. It is understood that the dispersed phase short-passes in the reactor. Therefore, in order to proceed the reaction without the disperse phase short-passing in the reactor, the Archimedes number such that t _D / t _C = 1.0 (that is, the Archimedes number starting to become t _D / t _C <1.0 It is necessary to carry out the suspension polymerization reaction in a reaction system having a small Archimedes number). The Archimedean number at which the value of t _D / t _C begins to deviate from 1.0 is the critical Archimedean number (Ar
(represented by c). Further, when the specific gravity of the dispersed phase is heavier than that of the continuous phase, t _D / t _C > 1.0.

FIG. 5 shows the number of Taylor and the number of Ar when Arc is obtained by variously changing the Archimedes number and the Taylor number.
The relationship with c is shown. From FIG. 5, it is clear that Arc changes depending on the Taylor number, and Arc increases as the Taylor number increases. That is, FIG.
Indicates that it is necessary to increase the Taylor number when dealing with a reaction system in which the Archimedes number increases. Further, from FIG. 5, Taylor number (Ta) and Arc
When the Arc is less than 7 × 10 ^−4, Ta = 1.
It is understood that 16 × 10 ⁵ Ar + 38.8 and Ta = 8.12 × 10 ⁵ Ar-367 when Arc is larger than 7 × 10 ⁻⁴ . Therefore, in order to proceed the reaction without the dispersed phase short-passing in the reactor, the Arc is 7 × 10 ^−4.
In the following cases, at least the Taylor number is 1.16 × 10 ⁵ Ar
And Tasu38.8 above, Arc is 7 × 10 ^{- 4} is greater than is required to be at least the Taylor number 8.12 × 10 ⁵ Ar-367 or more.

In the present invention, the Taylor number is
If it exceeds 2000, Taylor vortices start to be disturbed and the plug flow property of the continuous phase deteriorates, which is not preferable.

Therefore, the Taylor number used in the present invention is within the range of 1.16 × 10 ⁵ Ar + 38.8 ≦ Ta ≦ 2000 (region in FIG. 5) when the Archimedes number is 7 × 10 ⁻⁴ or less, When the Archimedes number is larger than 7 × 10 ⁻⁴ , it is preferably within the range of 8.12 × 10 ⁵ Ar−367 ≦ Ta ≦ 2000 (region in FIG. 5). More preferably, it is in the above-mentioned range or is 40 ≦ Ta ≦ 1600, and particularly preferably 40 ≦ Ta ≦ 800. The Taylor number used in the present invention is the physical properties of the reaction system to be handled (specific gravity of the polymerizable monomer droplets, specific gravity and viscosity of the continuous phase containing the dispersant, etc.) and the particle size of the intended polymer beads, that is, the reaction system to be handled. It is appropriately changed within the above range according to the Archimedes number in. Within the above Taylor number range, the polymerizable monomer droplets can be reacted up to the desired reaction rate without short path or floating or sedimentation in the reactor, and a polymer having a uniform particle size. Beads can be obtained in high yield.

The uniformity of particles in the polymer beads produced by the suspension polymerization method of the present invention can be represented by the dispersion coefficient [(standard deviation / average diameter) × 100] of the particle size distribution. According to the suspension polymerization method of the present invention, polymer beads having a particle size distribution with a dispersion coefficient of 20% or less, preferably 15% or less, more preferably 10% or less are produced. The yield is given by the weight ratio of the supplied polymerizable monomer and the obtained polymer.

In the present invention, the suspension in which the polymerizable monomer droplets are dispersed is placed in the reactor (that is, the annular portion of the coaxial double rotating cylinder having the stationary outer cylinder and the rotatable inner cylinder). It may be prepared or may be prepared outside the reactor, and the suspension may be fed into the reactor after preparation. The method for preparing a suspension in which the polymerizable monomer droplet groups are dispersed in the present invention will be described below.

The suspension in which the polymerizable monomer droplet group in the present invention is dispersed is usually formed by using a droplet forming device. This droplet forming device comprises a porous member such as a multi-nozzle, a porous orifice plate or a porous membrane. The polymerizable monomer droplet group in the suspension preferably has a uniform size (or droplet diameter, hereinafter referred to as size). The polymerizable monomer droplet group formed through the porous member as described above has a sufficiently uniform size, but by applying the vibration method or the electric field method at the same time, the size uniformity can be further improved. be able to.

The diameter of the ejection holes of the multi-nozzle or the multi-orifice plate used in the present invention depends on various factors such as the physical properties of the continuous phase liquid containing the dispersant and the polymerizable monomer which is the liquid to be formed into droplets, vibration, and the like. , But is largely determined by the size of the target droplet. Generally, the size of the polymerizable monomer droplets is 5 to 10000.
Since the appropriate diameter is μm, the diameter of the ejection hole is 2 to 5000 μm.
Is suitable, and 3 to 2000 μm is more preferable. It is appropriate that the array pitch of the ejection holes is 10 to 200 times the hole diameter.
It is more preferably up to 100 times.

The jetting speed of the polymerizable monomer, which is the liquid to be turned into liquid droplets, jetted from the jet holes is determined by the Reynolds number, and it is necessary to form a laminar flow in order to obtain a droplet group having a uniform size. . The Reynolds number is the following formula: Re = D · u · ρ / μ (where Re is the Reynolds number, D is the diameter of the ejection hole, u is the ejection velocity, ρ is the density of the liquid to be dropletized, and μ is It represents the viscosity of the liquid to be dropletized). In the present invention, when the Reynolds number is less than 10, the flow rate becomes small and the production efficiency decreases, which is not preferable. Also,
If it exceeds 2000, a turbulent flow region is formed and droplet groups having a uniform size are not generated, which is not preferable. Therefore, it is appropriate that the Reynolds number is in the range of 10 to 2000,
The range of 20 to 1000 is more preferable. By setting the ejection speed of the polymerizable monomer that is the liquid to be formed into droplets so that it falls within the range of the Reynolds number, it is possible to obtain a droplet group of the polymerizable monomer having a uniform size.

When a suspension in which the polymerizable monomer droplets are dispersed is prepared in the reactor, the jetting holes of the polymerizable monomer are provided on the lower surface or the upper surface of the annular portion of the double rotating cylinder. Alternatively, it may be provided on the side surface of the annular portion. Also, when preparing a suspension outside the reactor,
It is possible to provide a droplet generation unit having a jet port outside the reactor, and to supply the suspension prepared therein into the reactor.

When a multi-nozzle, a porous orifice plate or a porous membrane is used as the porous member, in order to increase the size uniformity of the polymerizable monomer droplets,
It is preferable to vibrate the continuous phase containing the dispersant and / or the liquid to be dropletized of the polymerizable monomer ejected from the ejection holes. The vibration method used in the present invention may be any as long as it has a vibration characteristic capable of dispersing the jet flow into a uniform droplet group, and its frequency is generally 10 to 100000 Hz. Yes, 20-50000
Hz is more preferable. As a concrete vibrating means, for example, a mechanical oscillator, an electroacoustic oscillator, a hydroacoustic oscillator, an electromagnetic oscillator, a magnetoresistive transducer, a piezoelectric oscillator, or the like can be used. The vibrating means may be connected to a nozzle to vibrate the nozzle, or may be connected to a reactor or a droplet generator outside the reactor to connect the liquid of the polymerizable monomer in the reactor or the droplet generator. The liquid to be dropletized may be vibrated. As described above, both the continuous phase containing the dispersant and the polymerizable monomer that is the liquid to be formed into droplets, or both of them are formed by forming a group of polymerizable monomer droplets while vibrating, thereby forming A suspension in which uniform droplet groups are dispersed can be obtained.

When a multi-nozzle or a porous orifice plate is used as the porous member, it is also preferable to apply the electric field method in order to improve the size uniformity of the polymerizable monomer droplets. As the electric field method, for example, a method in which an electrode is provided in a continuous phase containing a dispersant, and an AC or DC voltage is applied between the electrode and the ejection hole to miniaturize the liquid to be dropletized of the polymerizable monomer Can be applied. As the voltage application conditions, it is appropriate that the AC frequency is 1 to 30000 Hz and the voltage is 200 to 5000 V in the case of an AC electric field, and the voltage is 10 to 5000 in the case of a DC electric field.
Suitably V.

As a method of forming a group of polymerizable monomer droplets using a porous film as a porous member, for example, the polymerizable monomer is made into a continuous phase containing a dispersant through a porous film having uniform pores. A method of press-fitting and dispersing can be applied, and by such a method, a group of polymerizable monomer droplets of uniform size is prepared. In this method, under normal operating conditions (for example, pressure conditions), the size depends only on the pore size and not on the polymerizable monomer liquid flow rate. The pore size can be appropriately selected in the range of 50 nm to 50 μm according to the particle size of the droplet.

When a group of polymerizable monomer droplets is formed using a porous membrane, the continuous phase is vibrated to prevent the droplets of the polymerizable monomer from adhering to the surface of the porous membrane. It is possible to form a group of polymerizable monomer droplets having a more uniform particle size.

As the polymerizable monomer used in the suspension polymerization method of the present invention, any polymerizable monomer generally used in suspension polymerization can be applied.
Preferred examples of the water-insoluble polymerizable monomer used in the present invention include styrene, α-methylstyrene,
Examples thereof include vinyl monomers such as divinylbenzene, acrylonitrile, acrylic acid esters and methacrylic acid esters, and mixtures thereof. If necessary, the polymerizable monomer can be diluted with a solvent, and as the diluent, for example, toluene, hexane or the like can be used. Preferred examples of the water-soluble polymerizable monomer used in the present invention include acrylamide, methacrylamide, fumaramide, acrylic acid,
Examples thereof include acrylic acid salts, methacrylic acid, and methacrylic acid salts.

For the water-insoluble polymerizable monomer, for example, water or a mixed solution of water and one or more water-miscible organic solvents can be used as the continuous phase liquid. Preferable examples of the water-miscible organic solvent include methanol, ethanol and the like. Further, for the water-soluble polymerizable monomer, for example, an aromatic hydrocarbon (eg, benzene, xylene, toluene, etc.) and an aliphatic hydrocarbon (eg, heptane, cyclohexane, etc.) which are immiscible with water are used as the continuous phase liquid. be able to.

Generally, in suspension polymerization, a reaction is carried out by dissolving a polymerization initiator in a polymerizable monomer. As the polymerization initiator, for water-insoluble polymerizable monomers, for example, benzoyl peroxide, organic peroxides such as lauroyl peroxide,
An azo compound such as azobisisobutylnitrile can be used, and for the water-soluble polymerizable monomer, a water-soluble free radical initiator such as persulfate or hydrogen peroxide can be used.

As the dispersant used in the present invention, any dispersant generally used in suspension polymerization can be applied. Examples of the dispersant used for the aqueous continuous phase include polymer protective colloids, surfactants, water-insoluble inorganic substances, and the like. Specifically, for example, polyvinyl alcohol, gelatin, starch, methylcellulose derivatives. , Polyacrylic acid salts, anionic surfactants, nonionic surfactants, calcium phosphate, calcium carbonate, magnesium pyrophosphate and the like. Examples of the dispersant used for the water-immiscible continuous phase include, for example, sorbitan fatty acid esters, polymer dispersants, and the like. Specifically, for example, sorbitan monostearate, sorbitan monolaurate, ethyl cellulose. , Benzyl cellulose, ethyl hydroxyethyl cellulose and the like.

The suspension polymerization method of the present invention includes a batch method and a continuous method. In the batch method, for example, a device as shown in FIG. 1 is used. The batch method will be described with reference to FIG. The continuous phase containing the dispersant and the polymerizable monomer solution are supplied to the droplet generator 7 from the continuous phase containing tank 10 and the polymerizable monomer storage tank 11. After the slurry of the polymerizable monomer droplet group is formed by the droplet generation device 7, the slurry of the polymerizable monomer droplet group is supplied to the gap between the outer cylinder 2 and the inner cylinder 1. At this time, the gap between the outer cylinder 2 and the inner cylinder 1 may be previously filled with a continuous phase containing a dispersant. This device has an exhaust port 5. The inner cylinder 1 is rotated at a predetermined rotation speed by a motor 4. After supplying a predetermined amount of slurry of the polymerizable monomer droplets, warm water is supplied to the jacket 3 through the warm water inlet 8 and the warm water outlet 9.
By further discharging and circulating, the inside of the reactor is adjusted to a predetermined temperature to carry out the polymerization reaction. After the reaction is completed, the slurry of polymer beads is discharged from the slurry outlet 6. The polymer beads thus obtained have a uniform particle size.

In the apparatus shown in FIG. 1, the droplet generator 7 is installed in the lower part of the reactor. The apparatus in which the droplet generator 7 is installed in the lower part of the reactor is a polymerizable monomer. This is effective when the specific gravity of the droplet group is smaller than that of the continuous phase. When the specific gravity of the polymerizable monomer droplet group is higher than the specific gravity of the continuous phase, it is preferable to install the droplet generating device 7 at the upper part of the reactor as shown in FIG.

In the continuous method, for example, a device as shown in FIG. 2 is used. The continuous method will be described with reference to FIG. The continuous phase containing the dispersant and the polymerizable monomer solution are continuously supplied to the droplet generation device 7 from the continuous phase containing tank 10 and the polymerizable monomer storage tank 11. After the slurry of the polymerizable monomer droplet group is formed by the droplet generation device 7, the slurry of the polymerizable monomer droplet group is continuously supplied to the gap between the outer cylinder 2 and the inner cylinder 1. At this time, the gap between the outer cylinder 2 and the inner cylinder 1 may be previously filled with a continuous phase containing a dispersant. The inner cylinder 1 is rotated at a predetermined rotation speed by a motor 4. A constant flow rate slurry of droplets of polymerizable monomer is continuously fed to the reactor. Hot water is supplied to the jacket 3 from the hot water inlet 8, discharged from the hot water outlet 9 and circulated to adjust the temperature inside the reactor to a predetermined temperature to allow the polymerization reaction to proceed. The polymer beads in which the reaction has progressed may be completed in the present reactor, or after being discharged from the present reactor, an aging tank having an exhaust port 5.
The reaction may be completed at 12. The slurry of polymer beads which has completed the reaction is continuously discharged from the slurry outlet 6. The polymer beads thus obtained have a uniform particle size.

In the case of the continuous method, the droplet generator 7 may be installed at either the lower part or the upper part of the reactor, but in practice, the specific gravity and the polymerizable property of the continuous phase and the polymerizable monomer droplet group are high. The size is appropriately selected in consideration of the size of the monomer droplet group, the continuous phase, the flow rate of the polymerizable monomer droplet forming target liquid, and the like.

The polymerization temperature is appropriately selected in consideration of the decomposition temperature of the polymerization initiator to be used, the boiling point of the continuous phase, etc., but is generally preferably about 40 to 95 ° C.

[0032]

According to the suspension polymerization method according to the present invention,
Coaxial double-rotating circle with a rotating outer cylinder and a rotatable inner cylinder
Archimedean number (represented by Ar) is 7 × 10 in the annular part of the cylinder.
^-FourIn the following cases, the Taylor number (represented by Ta) is 1.16 × 10
^FiveWithin the range of Ar + 38.8 ≦ Ta ≦ 2000, the Archimedes number is
7 x 10^-FourIf it is larger, the Taylor number is 8.12 × 10^FiveA
Rotate the inner cylinder so that r-367 ≤ Ta ≤ 2000.
While pouring, insert a porous member into the continuous phase containing the dispersant.
Polymerizable monomer formed by introducing a polymerizable monomer
-The polymerization reaction takes place in a suspension in which droplets are dispersed.
It

When suspension polymerization is carried out in this manner,
Due to the good and uniform degree of radial mixing in the annulus of the coaxial double-rotating cylinder, the polymerizable monomer droplets in the Taylor vortex do not split / coalesce and depend on the Archimedes number. Since an appropriate Taylor number range is used, the reaction of the polymerizable monomer droplets proceeds to the target reaction rate without short path or floating or sedimentation in the reactor, and polymer beads having a uniform particle size are formed. It will be produced in high yield. Further, in the axial direction of the annular portion of the coaxial double-rotation cylinder, the degree of mixing is small and it is close to the plug flow. Therefore, by continuously supplying the polymerizable monomer droplets to the apparatus, polymer beads having a high polymerization rate can be obtained. Will be continuously manufactured.

[0034]

EXAMPLES The present invention will be described in detail below with reference to examples, but it goes without saying that the present invention is not limited to the following examples. Example 1 A polymerizable monomer solution having a uniform particle size (lauryl acrylate / vinyl acetate / divinylbenzene / lauroyl peroxide) was used in a droplet generator filled with a 2% by weight aqueous polyvinyl alcohol solution (specific gravity 0.99, viscosity 2 cp). =
67/23/9/1; specific gravity 0.97). The droplet generator is installed in the lower part of the coaxial double-rotation circular reactor, and the piezoelectric vibrator is mounted in the lower part of the droplet generator. The number of orifice holes is 19, the pitch width is 1.5 mm, and the hole diameter is 30 μm. The polymerizable monomer solution was jetted from the orifice holes into the continuous phase containing the dispersant at a flow rate of 0.3 g / min per hole, and a sine wave vibration of 5000 Hz was applied to the particles.
A 120 μm droplet was formed (Ar = 2.05 × 10 ⁻³ ). Further, a 1% by weight polyvinyl alcohol aqueous solution which is a continuous phase containing a dispersant was continuously supplied to the droplet generation part at a flow rate of 57 g / min.

The slurry of the formed droplet group was continuously supplied to the lower portion of the coaxial double-rotation cylindrical type reactor from the upper portion of the droplet generation device to advance the polymerization reaction. The outer diameter of the inner cylinder of the coaxial double rotation cylindrical reactor is 100 mm, the inner diameter of the outer cylinder is 150 mm, the height is 1000 mm, the reactor volume is 98 ml, and the inner cylinder is 35 rpm.
It was rotated with (Taylor number 1570). The inside of the inner cylinder has a structure in which a heat medium flows, and the temperature inside the reactor was set to 75 ° C. The residence time was about 2.5 hours, and a slurry of polymer beads having a uniform particle size was continuously obtained from the upper part of the reactor. As a result of measuring the particle diameter of the obtained polymer beads (measuring instrument: LS-130, manufactured by Coulter, Inc.), the volume average diameter was 120 μm, the dispersion coefficient was 8%, and the yield was 98%.

Example 2 Porous glass having a diameter of 10 mm, a length of 180 mm and an average pore diameter of 0.9 μm
Distribute 10 membranes with 1% by weight of polyvinyl al as a continuous phase
Droplets filled with a Cole solution (specific gravity 0.99, viscosity 0.9 cp)
In the production apparatus, a polymerizable monomer having the same composition as in Example 1
Are pressed into the continuous phase through a glass porous membrane to form droplet groups.
Formed (particle size 5 μm, Ar = 3.78 × 10 ^-6). Also, the liquid
The drop generator is equipped with a vibrator that vibrates in the continuous phase.
To disperse the polymerizable monomer. Polymerizable Mono
Mar, 19 g / min, continuous phase, 57 g / min
did. The slurry of the formed droplet group is transferred from above the droplet generator.
Continuously fed to the lower part of the coaxial double-rotating cylindrical reactor,
The combined reaction proceeded. Temperature in the reactor is 75 ℃, average retention
The time was 2.0 hours. Inner cylinder 5 rpm (Taylor number 51
Polymerization reaction was carried out by rotating at 0). Similar to Example 1
As a result of measuring the particle size of the polymer beads obtained by
The product average diameter is 5 μm, the dispersion coefficient is 17%, and the yield is 99%.
It was

Example 3 Under the same conditions as in Example 1, 9800 ml of a suspension having a droplet concentration of 30% by weight was formed, and the suspension was filled in the reactor used in Example 1 and the same as in Example 1. The polymerization reaction was carried out as a batch reaction under the conditions. The volume average diameter of the obtained polymer beads is 120μ.
m, the dispersion coefficient was 8%, and the yield was 98.5%.

Example 4 A polymerizable monomer solution having a uniform particle size [in a droplet generator of Example 2 filled with cyclohexane (specific gravity 0.78, viscosity 0.5 cp) as a continuous phase containing ethyl cellulose as a dispersant] 80 g of acrylic acid (510 g) is neutralized with 600 g of 30 wt% sodium hydroxide aqueous solution, 0.4 g of potassium persulfate as a polymerization initiator and Denacol EX-8 as a cross-linking agent.
20.4 g of 10 (manufactured by Nagase Kasei Co., Ltd.) and 4 of ion-exchanged water
A droplet group having a specific gravity of 1.20] was formed (particle size: 5 μm, Ar = 7.42 × 10 ⁻⁴ ). In addition, cyclohexane, which is a continuous phase, was continuously supplied at a flow rate of 50 g / min.

A droplet group formed was continuously supplied from the upper part of the reactor to a coaxial double-rotating cylinder type reactor filled with cyclohexane containing ethyl cellulose as a dispersant to proceed the polymerization reaction. Inner cylinder 10 rpm (Taylor number 668)
I rotated it. The temperature in the reactor is 72 ° C, the average residence time is
It was 2.0 hours. As a result of measuring the particle size of the polymer beads obtained in the same manner as in Example 1, the volume average diameter was 170.
μm, the dispersion coefficient was 15%, and the yield was 98.5%.

Comparative Example 1 When the number of rotations of the inner cylinder was 5 rpm (Taylor number 455) and the other conditions were the same as in Example 1, the polymerization reaction was carried out.
The volume average diameter of the obtained polymer beads was 120 μm, the dispersion coefficient was 9%, and the yield was 65%. From the above Examples and Comparative Examples, the Archimedes number in the reaction system was 7 × 10 ^−4.
In the following cases, the Taylor number is within the range of 1.16 × 10 ⁵ Ar + 38.8 ≦ Ta ≦ 2000, and when the Archimedes number in the reaction system is larger than 7 × 10 ⁻⁴ , 8.12 × 10 ⁵ Ar-367 ≦ Ta
It is clear that when the polymerization reaction is carried out with a Taylor number within the range of ≦ 2000, polymer beads having a uniform particle size can be obtained in a high yield.

[0041]

According to the suspension polymerization method of the present invention,
A coaxial outer cylinder with a stationary outer cylinder and a rotatable inner cylinder.
Archimedes number (represented by Ar)
Is 7 × 10 ^-FourIn the following cases, the Taylor number (represented by Ta) is
1.16 x 10^FiveAr + 38.8 ≦ Ta ≦ 2000, Archime
The number of deaths is 7 × 10^-FourIf it is larger, the Taylor number is 8.12
× 10^FiveInner circle so that Ar-367 ≤ Ta ≤ 2000
By rotating the cylinder, it becomes a continuous phase containing dispersant.
Formed by introducing a polymerizable monomer through the porous member
Taylor in a suspension in which droplets of polymerizable monomer are dispersed
The polymerization reaction can be carried out while generating a vortex.

When the suspension polymerization is carried out in this manner, the polymerizable monomer droplets in the Taylor vortex are separated because the degree of radial mixing in the annular portion of the coaxial double-rotating cylinder is good and uniform. Since it does not split / unify and uses an appropriate Taylor number range according to the Archimedes number, the polymerizable monomer droplets do not short pass or float or settle in the reactor, and the desired reaction rate Reaction progresses to. Therefore, according to this method, polymer beads having a uniform particle size can be produced in high yield.

In the axial direction of the annular portion of the coaxial double-rotating cylinder, the degree of mixing is small and it is close to the plug flow. Therefore, by supplying the polymerizable monomer droplet group continuously to the apparatus, high polymerization can be achieved. The rate of polymer beads can be produced continuously.

[Brief description of drawings]

FIG. 1 is a schematic view of an apparatus used in the batch method of the present invention.

FIG. 2 is a schematic view of an apparatus used in the continuous method of the present invention.

FIG. 3 is a schematic view of an apparatus used in the batch method of this reaction.

FIG. 4 is an explanatory diagram of a critical Archimedes number.

FIG. 5 is a relationship diagram between a critical Archimedes number and a Taylor number.

[Explanation of symbols]

 1 Inner Cylinder 2 Outer Cylinder 3 Jacket 4 Motor 5 Exhaust Port 6 Slurry Outlet 7 Droplet Generator 8 Hot Water Inlet 9 Hot Water Outlet 10 Continuous Phase Reservoir 11 Polymeric Monomer Reservoir 12 Aging Tank

Claims (3)

[Claims] 1. A suspension of a polymerizable monomer droplet group dispersed in a continuous phase containing a dispersant in an annular portion of a coaxial double rotating cylinder having a stationary outer cylinder and a rotatable inner cylinder. , If the Archimedes number (represented by Ar) is 7 × 10 ⁻⁴ or less, the Taylor number (represented by Ta) is 1.16 × 10 ⁵ Ar + 38.8 ≦ T
Within the range of a ≦ 2000, when the Archimedes number is larger than 7 × 10 ⁻⁴ , the Taylor number is 8.12 × 10 ⁵ Ar−367 ≦ Ta ≦ 20
A suspension polymerization method characterized in that polymer beads are produced by polymerizing while rotating an inner cylinder so as to be within a range of 00. 2. The suspension polymerization method according to claim 1, wherein the polymer beads are produced with a dispersion coefficient of 20% or less. 3. A suspension in which a group of polymerizable monomer droplets is dispersed is applied to the polymerizable monomer via a droplet forming device while vibrating both or both of the continuous phase and the polymerizable monomer. The suspension polymerization method according to claim 1 or 2, which is formed by introducing it into a continuous phase.