JP2875389B2 - Method for producing polymer beads - Google Patents

Description

The present invention relates to a method for producing polymer beads having a narrow particle size distribution and an apparatus for producing the same.

The polymer beads obtained by the present invention have an extremely small particle size and a narrow particle size distribution, and are mainly used as a packing material for liquid chromatography. The packing material for liquid chromatography is used for analysis (4 ~
Polymer beads produced by the method of the present invention can be used as a packing material for liquid chromatography for both of them.

[Prior Art] A packing material for liquid chromatography is generally used by filling a column with a porous spherical polymer (porous or polymer beads), and a liquid passes through the packed polymer bead layer. Therefore, the polymer beads are required to have a uniform particle size in order to minimize the passage resistance of the liquid. If the particle size is non-uniform, the liquid flow becomes non-uniform due to resistance, and the separation efficiency in the column decreases, so the column becomes longer to compensate for this phenomenon, and therefore the analysis (preparation) time becomes longer, In addition, the amount of liquid (solvent) to be passed increases, resulting in an uneconomical device.

Various methods have been proposed for producing polymer beads. For example, in JP-A-56-5140, a monomer liquid is injected into a dispersion medium, the monomer liquid is suspended and dispersed in the dispersion medium, and polymerized by heating to obtain polymer beads.
In suspension polymerization, it is difficult to control the particle size of the polymer beads, and the particle size distribution of the beads has a wide Gaussian distribution, and it is necessary to sieve in order to obtain polymer beads having a uniform particle size distribution.

Here, if polymer beads having a narrow particle size distribution (uniform particle size) are to be obtained, the yield of the polymer beads decreases and the cost of sieving increases. In addition, disposal of the polymer beads having a particle size other than the intended size is also a problem. Therefore, a method for producing a polymer bead having a desired uniform particle size has been strongly desired.

Various methods for producing polymer beads having a uniform particle size have been proposed. For example, JP-A-57-102905, 57-73002
In JP-A No. 61-115902, a monomer composition liquid is jetted and dispersed into a dispersion medium to form polymer beads.
In No. 73002, a monomer composition flow is vibrated and crushed by a piston member to obtain polymer beads having a uniform diameter. In Japanese Patent Application Laid-Open No. 61-115902, a monomer composition liquid is ejected from a vibrating thin tube to form uniform liquid droplets and then polymerize to obtain uniform polymer beads.

However, the particle size of each of the polymer beads obtained by these known techniques is several hundred microns or more, and the technology for producing polymer beads (4 to 200 μm) which can be used as a filler for liquid chromatography, in particular, as a filler for analysis. Can't be turned.

[Problems to be Solved by the Invention] In these known methods, the diameter of the jetting tubule is large, so that the jetted monomer stream becomes large droplets. Inevitably, the particle size increases.

In this case, if the velocity of the ejected monomer is increased, fine monomer droplets are generated, but the particle size distribution is widened and cannot be a technique for producing polymer beads having a uniform particle size distribution.

In addition, to reduce the large monomer droplets dispersed in the dispersion medium, it is sufficient to stir with a stirring blade or the like and disperse the large particles with a shearing force, but the particle diameter of the cut monomer droplets is uniform. And the particle size distribution becomes a wide Gaussian distribution like suspension polymerization.

An object of the present invention is to develop a method for producing polymer beads having a very small particle diameter and a narrow distribution suitable for a packing material for liquid chromatography, and an apparatus for producing the same.

[Means for Solving the Problems] The present inventors conducted research on a method for producing a polymer particle having a uniform particle size (narrow particle size distribution) having a particle size of 4 to 200 μm, which is most suitable as a carrier for chromatography, and studied the method for preparing a dispersion medium. The monomer composition is jetted into the dispersion medium by high pressure from the fine pores of the metal dispersion plate that vibrates finely to generate droplets of the monomer composition having a narrow particle size distribution, Then, a method for producing polymer beads having a narrow particle size distribution, characterized in that the dispersion medium is heated to polymerize the monomer composition, and (a) a pump for supplying the monomer composition to the monomer ejection tank; Immerse a metal dispersion plate with a large number of micropores in the dispersion medium of the polymerization tank,
A monomer ejection tube with fine vibration and piping for receiving the monomer composition supplied from the pump,
(C) We succeeded in developing a polymer bead manufacturing device that has a heating device and a polymerization tank containing a dispersion medium for dispersing and polymerizing the monomer composition droplets from the monomer ejection tank. The metal dispersion plate used in the present invention is a strong metal,
For example, nickel, molybdenum, stainless steel, etc.
This is processed by laser beam, electric discharge machining, plating method, etching and the like or a combination of these techniques to form a fine hole, and the hole diameter needs to be as uniform as possible. If the pore size is not uniform, the size of the ejected droplets of the monomer composition becomes non-uniform according to the pore size, and polymer beads having a wide particle size distribution are obtained.

It is necessary that the thickness of the metal dispersion plate withstands the pressure required for ejecting the monomer composition liquid and does not significantly deform due to the pressure.

Generally, when the size of the polymer beads requires a small particle size, the pore size of the micropores becomes small, and the monomer composition solution requires a large pressure. For example, when the ejection area of the dispersion plate is 1 cm ² , a thickness of 100 μm is required when the ejection hole diameter is 50 to 20 μm, and a thickness of 200 μm is required when the ejection hole diameter is 20 to 10 μm.

However, the required particle size of the polymer beads is small,
Obviously, when mass production is required, it is necessary to reduce the fine pore size and increase the area of the metal dispersion plate from which the monomer composition is ejected.

On the other hand, in order to reduce the diameter of the micropores, it is necessary to reduce the thickness of the metal plate in order to be able to provide micropores with an accurate pore diameter. Since the required pressure requires a higher pressure, it was extremely difficult to simply increase the size of the powder. However, sintered powder plates (for example, metal powder having a particle size of several μm to several hundred μm, ceramic powder, etc.) Sintering,
Many types of sintered filters are commercially available as filters. The metal film is formed by plating a metal on one side of the method, and the plated metal film may be drilled with a laser beam or the like. In the case of a commercial-scale metal plate, the number of micropores may be as large as 10 ⁶ to 10 ⁸ , and in such a case, an electronic integrated circuit such as an IC, LSI or VLSI may be used. A dispersion plate having an arbitrary hole diameter and an arbitrary pitch may be manufactured and used by boring by etching using a lithography technique.

Alternatively, predetermined fine holes may be provided in a thin metal plate, and the fine holes may be bonded to the sintered powder plate with an adhesive or solder.

Such a sintered powder plate can be arbitrarily selected, such as powder material, powder particle size, fine pore size, rigidity, strength, etc., for example, when Ni-P electroless plating is performed on a stainless steel-sintered powder plate. The tensile strength of the sintered plate is 700 kg / cm ² , and the peel strength of the plating is extremely high.The metal on this plated surface can be bowled with a laser beam or the like to make a metal dispersion plate with fine holes with a uniform hole diameter. it can.

The distance between the micropores is required to be 10 to 100 times, preferably 30 to 50 times the diameter of the holes in order to eject the monomer composition.
If this interval is narrower than 10 times, the monomer composition adheres to the metal plate and drops into the dispersion medium, and is not ejected.
On the other hand, if the interval between the fine holes is large, the number of holes per unit area decreases, and the productivity decreases.

The hole diameter of the metal dispersion plate does not have to be the same diameter from the inlet side to the outlet side of the hole, and since the particle diameter of the monomer droplet is determined by the outlet side outlet diameter, only the outlet hole portion is adjusted to have the same diameter. Is also good.

As such a method, one method is to apply a plating treatment to a metal dispersion plate and to uniformly deposit metal on the hole surface to control the hole diameter to a predetermined value. In particular, if one side plating is performed only on the ejection outlet side, it is possible to manufacture a metal dispersion plate having a small pressure loss even if the hole diameter is the same.

A metal dispersion plate with a spout controlled in such a micron unit was attached to the bottom of the pressure-resistant spouting liquid tank where the vibrator was attached, and the monomer passed through an eye filter smaller than the spout diameter by a non-pulsating pump. The composition is caused to flow at a predetermined flow rate, and the monomer composition is jetted into the dispersion medium. Simultaneously, when fine vibrations are given by a vibrator, the ejected droplets of the monomer composition have a uniform particle size and are dispersed in the dispersion medium. By heating and polymerizing the monomer composition dispersed in such a uniform particle size as described above, it was confirmed that the polymer was polymerized in the state of the dispersed droplets and uniform polymer beads were obtained, thereby completing the present invention.

That is, in the present invention, a monomer composition is ejected at a predetermined flow rate (pressure) from a metal dispersion plate provided with a large number of fine holes vibrating finely to generate uniform monomer composition droplets in micron units. In this method, the polymer particles are polymerized as they are dispersed by heating and polymerizing them, thereby obtaining fine polymer beads having a uniform particle size.

The monomer composition used in the present invention is determined by the properties of the target polymer beads,
Generally, it is a mixture of a monofunctional vinyl compound, a polyfunctional vinyl compound (polyvinyl compound) as a crosslinking agent thereof, a diluent (precipitant), a polymerization initiator, and the like.

Although specific examples are not limited, styrene insoluble in a dispersion medium as a monofunctional vinyl compound,
Examples include methyl acrylate, acrylonitrile, and glycidyl methacrylate. Examples of the polyfunctional vinyl compound include divinylbenzene, ethylene glycol dimethacrylate, and trimethylolpropane triacrylate. Diluents (precipitants) include toluene, chloroparaffin, dichlorobenzene, trichlorobenzene, alcohols and esters.

Examples of the polymerization initiator include benzoyl peroxide, butyl peroxide, and azobisisobutyronitrile, which are generally used in the polymerization reaction of the vinyl compound and are soluble in the polymerization monomer.

As the dispersion medium, a solution in which 0.2 to 10% of a compound known as a protective colloid, such as CMC (carboxymethyl cellulose), PVA (polyvinyl alcohol), sodium polyacrylate, or gelatin, is dissolved in water can be used.

In the present invention, it is desirable to polymerize the monomer composition and the dispersant with the same density, but since the droplets of the monomer composition in the dispersion medium obtained by the present invention are extremely small, the monomer composition droplets Buoyancy (sedimentation force) is small, and the rate at which droplets coalesce is small.

However, if the density difference between the two is large, they tend to aggregate in the upper or lower layer of the polymerization tank, and stirring is required to prevent coalescence during the polymerization reaction. Since there is also a spread in the diameter distribution,
It is desirable to have the same density as much as possible and to have a gentle motion of the dispersion medium due to thermal convection. If the density is the same, the ejected droplets of the monomer composition spread uniformly in the dispersion medium, move slowly due to the thermal convection of the liquid, do not break coalescence, and are polymerized as the ejected and dispersed droplets, resulting in uniformity. It becomes polymer beads of a particle size.

To adjust the density of the monomer composition to match the density of the dispersion medium, the ratio of the monovinyl monomer to the divinyl monomer is in the range of 5 to 600 parts of the divinyl monomer to 100 parts of the monovinyl monomer by weight, and the diluent 50-300
The mixing may be carried out within the range of parts and in such a manner as to obtain physical properties according to the intended use such as hardness, surface area, pore distribution, pore volume, etc. of the polymer beads.

The monomer composition is ejected into the dispersion medium from the fine pores of the metal dispersion plate, and it is necessary to determine the fine pore diameter in order to obtain polymer beads having a desired particle diameter.
The relationship between the fine pore size and the polymer bead size cannot be determined uniquely because it is affected by the physical properties (viscosity), jetting conditions, etc., depending on the composition of the monomer composition, but the relationship is approximately as follows.

In order to continuously eject the monomer composition from the fine pores, it is necessary to mount a filter having a smaller diameter than the fine pore diameter in front of the metal dispersion plate, and it is difficult to prevent clogging without a filter.

The monomer composition is ejected from a monomer ejection tank having a metal dispersion plate attached to the bottom thereof (as long as the metal dispersion plate can vibrate, and the ejection tank may be a part of a pipe). The method is performed at 5 to 100 Hz, preferably 20 to 50 Hz. Further, the vibration width needs to be 1 mm or less, and a vibration width of 0.5 mm or less is preferable. When the vibration width is larger than 1 mm, the dispersion medium is agitated by the movement of the ejection tank immersed in the dispersion medium, so that the ejected monomer droplets are also cut, resulting in a particle size distribution in which the distribution of the small particle portion is greatly expanded.

Further, the ejection speed of the monomer composition from the metal dispersion plate into the dispersion medium is 5 cm / sec to 20 cm / sec, preferably 7 cm / sec to
It is in the range of 14 cm / sec and needs to be kept constant. If the jetting speed is too high, the jetted monomer droplets will be smaller than the target particle size and the particle size distribution will be wide, and eventually polymer beads having a uniform particle size cannot be obtained. On the other hand, if the flow rate is low, the monomer liquid is not jetted out and oozes out of the metal dispersion plate, and uniform polymer beads cannot be obtained.

The feeding of the monomer liquid requires a non-pulsating pump or a gas pressurization that does not change the flow rate. When the flow rate changes, monomer droplets having a uniform particle size are not obtained.

Next, an apparatus for carrying out the present invention will be described with reference to the drawings.

In FIG. 1, 1 is a monomer storage tank, 2 is a monomer composition containing a diluent (precipitant), a polymerization initiator and the like, and 3 is a pressure-resistant monomer ejection tank. A filter 4 is attached to the upper part of the monomer ejection tank, and the monomer liquid enters the ejection tank after being filtered. A metal dispersion plate 5 having fine holes having a determined hole diameter for determining the particle diameter is welded to a lower portion of the jet tank. A vibrator 6 is attached to the monomer ejection tank, and this causes a fine vibration of the metal dispersion plate. The metal dispersion plate is immersed in a dispersion medium 8 in a polymerization tank 7.

The polymerization tank has a heating device 9 for heating the dispersion medium to a predetermined temperature. The monomer composition is sent from a monomer storage tank to a monomer ejection tank from a stainless steel pipe 12 to which a pressure gauge 11 is attached by a non-pulsating pump 10 and is ejected into a dispersion medium.

Usually, after completion of the ejection of the monomer composition, the polymerization tank is heated, the dispersion medium is maintained at a predetermined temperature, and the droplets of the monomer composition are polymerized as they are to form polymer beads, which are washed and separated. Denature to give product.

[Action] Conventionally, a monomer composition is ejected from a capillary into a dispersion medium,
It is known to form small droplets and polymerize them into polymer beads. However, not only is it difficult to reduce the diameter because of the thin tube, but when the diameter is set as the object of the present invention, it becomes impossible to eject the monomer composition even when high pressure is applied. Was evident.

Therefore, relatively large diameter (0.1mm or more)
Tubing is used, and the size of the polymer beads is also 0.
The limit was about 5mm.

The present invention changes this thin tube to a metal dispersion plate and has a pore size of 1 to 4.
When the jetting speed of the monomer composition is set to 5 to 20 cm / sec while making fine pores of about 50 μm and finely oscillating under high pressure, polymer beads having a narrow particle size distribution of 4 to 200 μm, which were conventionally difficult to produce, Can be manufactured efficiently.

[Examples] Next, the present invention will be described with reference to Examples and Comparative Examples.

Example 1 80 g of styrene, 20 g of divinylbenzene, 80 g of chloroparaffin, 20 g of dichlorobenzene, and 2 g of benzoyl peroxide as a polymerization initiator were measured, placed in a monomer storage tank, and mixed to obtain a monomer composition. At this time, the density of the monomer composition was 1.005.

The monomer composition is removed from the monomer storage tank by a non-pulsating pump.
10mmφ with a μm sintered metal filter attached
It is filtered and supplied to a 300 mmL monomer ejection tank.

In the lower part of the monomer ejection tank, a metal dispersion plate with 50 micron holes of 20 micron opened at a pitch of 1 mm by laser processing on a metal plate of stainless steel of 100 micron thickness is welded, and 0.1 mm at 30 Hz by vibrator Vibration is fine.

When the monomer composition part is sent to this monomer ejection tank at 7 ml / min, the monomer composition is equilibrated at a pressure of 3 kg / cm ² and ejected and dispersed in a dispersion medium.

The dispersion medium is PVA (polyvinyl alcohol) in 500 g of water
Ten parts were dissolved, and the density was almost balanced with the monomer composition. The monomer droplets jetted into the dispersion medium become mist and spread into the dispersion medium. After the dispersion is performed for about 30 minutes, when the dispersion medium is heated, the monomer composition starts polymerization with the dispersed particle size without being coalesced or cut by thermal convection. The polymerization reaction was carried out at 85 ° C. for 8 hours, followed by classification using a JIS sieve, and the particle size and ratio were determined. The results are as follows.

74 μm or more 5% 74 to 53 μm 93% 53 μm or less 2% (Comparative Example 1) A monomer composition and a dispersion medium exactly the same as in Example 1 were prepared, the monomer liquid was injected into the dispersion medium, and the mixture was stirred for 260 r with a stirring blade.
The mixture was stirred at pm for 16 minutes, and suspension polymerization was carried out at 85 ° C. for 8 hours by a conventional method. After the polymerization is completed, the polymer beads
Classification was performed using a JIS sieve, and the particle size distribution was determined.

 The results are shown below.

74 μm or more 28% 74 to 53 μm 37% 53 μm or less 35% (Example 2) A stainless steel metal plate having a thickness of 12 mm 200 microns
Fifty micropores of 10 μm were drilled at a pitch of 1 mm by laser processing, and these were welded to the bottom of a 10 mmφ monomer ejection tank.

40 g of commercially available divinylbenzene (containing 44% ethylstyrene), 40 g of trichlorobenzene, 20 g of toluene
g and benzoyl peroxide (1 g) were fed into the jetting tank at a flow rate of 2.5 ml / min from a non-pulsating pump. The metal dispersion plate was contained in a dispersion medium having the same composition as in Example 1, and the dispersion medium density was almost balanced with the monomer composition. When the monomer composition enters the monomer ejection tank, the pressure increases, and the monomer composition is ejected into the dispersion medium from the fine holes of the finely vibrating metal dispersion plate as in Example 1. The pressure equilibrates at 17 kg / cm ² and the monomer composition is atomized in the dispersion medium and spreads throughout. After about 30 minutes of dispersion, the dispersion medium was heated to initiate polymerization. Since the monomer composition and the density of the dispersion medium are substantially balanced, the polymerization is carried out with the dispersed particle size without coalescence or cutting of the droplets. Polymerization was carried out at 85 ° C. for 8 hours. After completion, the mixture was classified with a JIS sieve, and the particle size ratio was determined. The results are shown below.

44 μm or more 7% 44 to 25 μm 89% 25 μm or less 4% (Comparative Example 2) A monomer composition and a dispersion medium having exactly the same composition as in Example 2 were prepared, and 100 g of the monomer composition was dispersed in 500 g of the dispersion medium in one polymerization tank. The monomer composition was added, the mixture was stirred with a stirring blade at 320 rpm for 15 minutes, dispersed in a dispersion medium, and subjected to suspension polymerization by a conventional method at 85 ° C. for 8 hours. After completion of the polymerization, the produced polymer beads were classified by a sieve, and the particle size ratio was determined. The result is shown below.

44 μm or more 32% 44 to 25 μm 47% 25 μm or less 21% (Example 3) 400 micron holes of 10 μm are drilled at a pitch of 0.2 mm on a 12 mmφ, 200 μm thick stainless steel metal plate by laser processing. Nickel plating was applied to one side to reduce the micropore diameter.

Microscopic examination revealed that the micropores had been reduced to about 3.5 μm. This metal dispersion plate was attached to a monomer ejection tank by welding to produce a 10 mmφ × 300 mmL ejection tank.

Glycidyl methacrylate
A monomer composition in which 30 g, 20 g of ethylene glycol dimethacrylate, 20 g of isoamyl alcohol, 30 g of trichlorobenzene, and 1 g of benzoyl peroxide were dissolved and mixed was fed by a non-pulsation pump at a flow rate of 0.9 ml / min for 60 minutes.
The metal dispersion plate is contained in a dispersion medium of the same method as in Example 1, and is vibrated finely by a vibrator at 50 Hz at about 0.1 mm. When the monomer composition is supplied to the ejection liquid tank, the pressure increases, and the monomer composition is ejected from the metal dispersion plate. The pressure is
Equilibrium occurs at 60 kg / cm ² , and the droplets of the monomer composition ejected into the dispersion medium become mist-like and spread into the dispersion medium. After the ejection, the dispersion medium was heated and polymerized in the same manner as in Example 1 to obtain polymer beads. Classification was performed using a sieve, and the particle size ratio was determined. The results are shown below.

15 μm or more 6% 15 to 10 μm 82% 10 μm or less 12% The glycidyl group can be modified after ring opening.

(Comparative Example 3) A monomer composition and a dispersion medium having exactly the same composition as in Example 3 were prepared, and 100 g of the monomer solution was poured into 500 g of the dispersion medium in one polymerization tank, and the mixture was stirred at 950 rpm with a stirring blade. After stirring and dispersing for 8 minutes, suspension polymerization was carried out at 85 ° C. for 8 hours by a conventional method.

After the polymerization was completed, the polymer beads produced were classified with a sieve, and the particle size ratio was determined. The results are shown below.

15 μm or more 32% 15 to 10 μm 38% 10 μm or less 30% [Effect of the Invention] Conventionally, there is no technology for efficiently producing polymer beads having a particle size of 4 to 200 μm and a narrow particle size distribution required as a filler for liquid chromatography. Was. In particular, it is difficult to manufacture a fine tube having a fine inner diameter, for example, a thin tube having an inner diameter of 1 to 50 μm with a narrow distribution of diameters, and even if this is possible, the resistance is too large for ejecting the liquid from now on. It was thought that it could not be put to practical use.

The present invention solves the above-mentioned problem by finding that a dispersion plate having a high uniformity of fine pore diameter can be manufactured by using a thin metal plate by laser processing, plating processing, or the like. Particularly, the present invention has established a method for producing a polymer having a narrow particle size distribution by dispersing the monomer composition under pressure to maintain the jetting speed of the monomer composition.

The polymer beads produced by the method of the present invention have a particle size much smaller than that of conventional beads, and the yield of the target particle size is high. Further, the apparatus of the present invention can efficiently carry out the method of the present invention.

The present invention is particularly effective as a method for producing a polymer bead having a particle diameter of a micron unit required as a packing material for liquid chromatography.

[Brief description of the drawings]

FIG. 1 is a flow sheet of an apparatus for carrying out the manufacturing method of the present invention. 1. monomer storage tank, 2. monomer composition 3. monomer ejection tank, 4. filter 5. metal dispersion plate, 6. vibrator 7. polymerization tank, 8. dispersion medium 9. heating device, 10. pump 11. pressure gauge , 12. Stainless steel piping

Claims (6)

(57) [Claims] 1. A monomer composition having a narrow particle size distribution, which is immersed in a dispersion medium and jets the monomer composition into the dispersion medium from the fine pores of a finely vibrating metal dispersion plate under high pressure. A method for producing polymer beads having a narrow particle size distribution, wherein droplets of a product are generated, and then a dispersion medium is heated to polymerize the monomer composition. 2. The polymer beads according to claim 1, wherein the velocity at which the monomer composition is ejected from the fine holes of the metal dispersion plate is 5 to 20 cm / sec, and the diameter of the polymer beads is 4 to 200 μm. Production method. 3. A pump for supplying a monomer composition to a monomer jetting tank. 2. A metal dispersion plate having a large number of fine holes is immersed in a dispersion medium of a polymerization tank, and fine vibration (C) Dispersion for dispersing and polymerizing the monomer composition droplets from the monomer ejection tank, which has a heating device and has a heating device, and a piping for receiving the monomer composition supplied from the pump. A polymer bead manufacturing device consisting of a polymerization tank containing a medium. 4. The micropores of the metal dispersion plate have a diameter of 1 micropore.
4. The apparatus according to claim 3, wherein said fine holes are formed at an interval of 10 to 100 times the hole diameter. 5. The metal dispersion plate according to claim 3, wherein one side of the porous sintered plate is plated, and the metal dispersion plate is provided with fine holes in the plating. Polymer bead manufacturing equipment. 6. The production of polymer beads according to claim 3 or 4, wherein the metal dispersion plate is a porous sintered plate, and a metal plate having fine holes is bonded to one surface of the porous sintered plate. apparatus.