JPH0653806B2 - Method for producing uniform polymer particles - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing uniform polymer particles having a uniform particle size. More specifically, the base material of ion exchange resin,
The present invention relates to a method for producing uniform polymer particles that can be used as a raw material for foams, including a packing material for chromatography, a carrier for immobilizing an enzyme or a carrier for affinity chromatography.

[Prior Art] A dispersion method and a spray method are known as methods for producing spherical (including a spheroid in a broad sense, the same applies hereinafter) polymer particles.

In the dispersion method, a dilute solution of a polymer dispersed in a dispersion medium containing a surfactant is solidified by volatilizing the solvent (see JP-A-56-24430), or Polymer particles can be obtained by gradually adding a coagulant of small droplets to and solidifying (see JP-A-57-159801). Particles having a wide particle size distribution can be obtained by this method. Further, this method requires washing with not only water but also an organic solvent in order to remove the solvent, the dispersion medium and the surfactant from the solidified droplets.

As another method of the dispersion method, there is also known a method of obtaining a polymer particle by dispersing a polymerizable monomer in a dispersion medium and then polymerizing it, and the particle obtained by such a method also has a wide particle size distribution. There is. When these particles are magnified and observed with an electron microscope, it can be seen that finer spherical particles aggregate to form particles. It is thought that this structure is the cause, but when the suspension of particles obtained by this method is stirred with a magnetic stirrer or the like, a large amount of minute polymer waste is generated.

In the spray method, polymer particles are obtained by spraying a polymer solution into a coagulant. This particle also has a wide particle size distribution and a relatively large particle size (JP-A-52-12).
(See Japanese Patent No. 9788).

In recent years, a technique (hereinafter referred to as a vibration method) has been found in which a jet having a constant flow velocity is periodically disturbed to form uniform droplets.

By applying this technique to a method for producing a polymerizable monomer by a dispersion method, uniform polymer particles have already been obtained (see JP-A-57-102905). However, these particles have the drawback that polymer scraps are likely to occur, as pointed out above.

There are also examples in which polymer particles and capsules are produced from a polymer solution by applying the vibration method (see JP-A-52-129686 and JP-A-59-112833), but JP-A-52-1296.
In the example disclosed in Japanese Patent No. 86, a very dilute solution of the polymer, and thus a low viscosity solution, is used.
In the example disclosed in Japanese Patent No. 2833, since the nozzle itself is directly vibrated, the frequency is limited to a small value, and particles having a large particle size are produced. In each of the examples, multiple tubular nozzles are used, and two or more kinds of solutions are simultaneously ejected while maintaining a delicate balance.

[Problems to be Solved by the Invention] As described above, the prior art has a drawback that the particle size distribution of the polymer particles is wide or minute polymer scraps are generated from the polymer particles. Has the drawback of using complex devices such as multiple tubular nozzles and requiring subtle manipulation.

An object of the present invention is to provide a method for producing uniform polymer particles, which eliminates these drawbacks and can easily obtain spherical uniform polymer particles in which minute polymer scraps do not occur.

[Means for Solving Problems] The present inventors have found that these problems can be solved by the following manufacturing method. That is, while the polymer solution is allowed to flow out from the opening at a constant flow rate, a constant periodic turbulence is applied to the outflowing solution by applying vibration from a vibration source to form uniform droplets with the same charge. After being ejected into the gas phase, the flight distance should be at least 30
After a flight distance of not less than cm, the droplets are present as a non-solvent of the polymer contained in the polymer solution and exhibit compatibility with the solvent of the polymer solution, and below the surface tension of the solvent of the polymer solution. When it penetrates into a coagulant that has a surface tension that allows it to wet naturally, it does not generate polymer scraps, and spherical uniform polymer particles with a narrow particle size distribution are complicated devices such as multiple tubular nozzles. The present inventors have found that they can be obtained even without using, and have completed the present invention.

[Examples] The term "spherical" as used herein means a shape having a spheroidal smooth surface. Also, uniform particles mean JI
Particles were classified by a wet sieve using water and alcohol as a dispersion liquid using S standard sieve, and the particles captured on each sieve were respectively collected, and after standing for a day and night, the sedimentation volume of each was measured. : (In the formula, Di is the opening of the sieve, Vi is the sedimentation volume of the particles captured on the sieve of the opening Di) within the range of ± 20% of the volume average particle diameter, more preferably It means that there are 80% by volume or more of the particles in the particle group within the range of ± 10%.

The presence or absence of fine particles of less than 5 μm and polymer debris is confirmed with a microscope or a Coulter counter (Coulter counter, manufactured by Coulter Co.).

In order to obtain strong polymer particles without generation of polymer scraps, which is one of the objects of the present invention, the concentration of the polymer solution must be several% by weight or more, although it depends on the molecular weight of the polymer. Such a solution depends on the measurement temperature, but 10
It is a solution of a polymer having a viscosity of cP or higher, preferably a viscosity of 50 cP or higher and a relatively high degree of polymerization. Further, if the viscosity of the solution exceeds 2000 cP, it becomes difficult to form droplets having a particle diameter of 1000 μm or less by the vibration method, so that the viscosity is preferably 2000 cP or less.

In order to make uniform droplets by the vibration method, the viscosity of the polymer solution and its surface tension, the flow velocity of the jet, the diameter of the opening from which the droplet is ejected, the vibration frequency of the vibration source and its displacement are It must be related and adjusted to a specific range (hereinafter, the state in which the above factors are adjusted within this range is called the synchronized state) (T.Sakai, Pro.
c. See ICLASS-1982, p37, 1982).

If the droplet diameter exceeds 1000 μm, it can be tuned by directly mechanically vibrating the opening (see the above reference). However, as the droplet diameter becomes smaller, the frequency of tuning increases, and a large amount of energy is required to vibrate the diameter of the opening. Therefore, the method of directly adding periodic turbulence to the solution is preferable. Especially the droplet size is 250
In the case of μm or less, the frequency of tuning is 3000 to 40,000 Hz, as disclosed in the specification of the present inventors (see Japanese Patent Laid-Open No. 62-191033).

FIG. 1 shows a device for obtaining such drops.

In FIG. 1, the vibrating rod (6) is connected to an appropriate vibration source, for example, a magnetostrictive element, an electrostrictive element or an electromagnetic coil type vibrator. In order to efficiently transmit these vibration energy to the vibrating rod (6), it is preferable to use an O-ring (7) having a small contact resistance for sealing with the cylinder (2). The distance between the nozzle (5) having the opening (12) and the tip of the vibrating rod (6) can be arbitrarily adjusted by the screw (11) of the cylinder (2) and the cylinder fixing nut (4). The nozzle (5) is fixed to the cylinder (2) by a nozzle fixing nut (3). An O-ring (8) seals between the nozzle (5) and the cylinder (2). The cylinder (2) is fixed to the fixing base (1) by a cylinder fixing nut (4).

The polymer solution sent from the gear pump etc. is the inlet (9)
Into the cylinder (2) from above and on the nozzle (5) the vibrating rod (6)
It ejects from the opening (12) while periodically receiving a pressure change due to the reciprocating motion of the. If necessary, the polymer solution in the cylinder (2) can be heated by the heater (13). The temperature sensor (14) is therefore also used for temperature management.

The distance between the nozzle (5) and the tip of the vibrating rod (6) is 5 mm, especially when the frequency is high enough to be included in the ultrasonic range.
The above is preferable. If this distance is less than 2 mm, cavitation may occur and the tip of the vibrating rod (6) or the inner surface of the nozzle (5) may be eroded.

Fixed base if needed to keep frequency more stable
A cooling water inlet / outlet (10) may be provided in (1).

When using this device, not only the low-viscosity solution but also the high-viscosity solution under high temperature and high pressure is ejected from the nozzle (5) while applying pressure that cyclically changes at various frequencies to form uniform droplets. can do.

Once formed, the uniform droplets move away from the nozzle (5) and move turbulently due to air resistance, and many droplets collide with each other and coalesce. However, J. H. Schneider and C. Hendricks, Review of Scientific Instruments, 35, 1349, 1964 (JH
Shneider and CDHendricks, Review of Scientific I
nstruments, 35 , 1349, 1964), it is possible to prevent this coalescence for a relatively long time by giving each droplet a charge of the same sign.

The droplets of the polymer solution discharged into the gas phase as described above are non-solvents of the polymer and exhibit compatibility with the solvent, and the droplets have a surface tension equal to or lower than the solvent of the polymer solution. It is allowed to enter after a lapse of a flight distance or more that stalls to a speed that does not cause large deformation to collide in a coagulant having a surface tension that naturally wets,
It becomes spherical uniform polymer particles.

If the surface tension of the coagulant is higher than the surface tension of the solvent of the polymer solution and the droplets do not naturally wet, for example, even if the specific gravity of the droplet is larger than that of the coagulant, the droplet remains on the surface of the coagulant for a long time. It floats and new droplets collide with the droplets one after another, forming a large coalescence. However, if the droplets that have fallen onto the coagulant are quickly covered with the coagulant, they will not coalesce even if they collide with new droplets, and this droplet will also be quickly covered with the coagulant, so that each droplet is an independent polymer particle. Becomes Such a coagulant approximates the surface tension of the solvent of the polymer solution as a rough guide, but is desirably selected from those having a surface tension smaller than that.

As disclosed in the specification of the present inventors (Japanese Patent Application No. 61-24591), the flow rate of the polymer solution ejected from the opening synchronized when the viscosity of the polymer solution is high and the droplet diameter becomes small, In other words, the initial velocity of the droplets is from several m / sec to several + m /
Since it reaches as long as a second, if these droplets are immediately introduced into the coagulating liquid, they are broken or flattened due to the impact of collision. In order to avoid this, it is necessary to reduce the flight speed of the liquid droplet before it enters the coagulant.

Although it has been described that the droplets can be prevented from coalescing for a relatively long period of time when the droplets are charged with the same sign, another effect of the present invention is that the droplets are charged with the same sign. Et al. Found that the flight speed of the droplet was suddenly stalled. In particular, droplets with a small particle size have a large initial velocity for synchronization, and if a charge of the same sign is not applied, they may be flatly deformed when entering the coagulant even after a flight distance of 2 m has passed. If the same electric charge is applied, the same droplets can be infiltrated into the coagulating liquid without deformation even at a flight distance of 30 cm.

In addition, it is important to prevent the coalescence of the droplets by minimizing the distance from the opening to the coagulant, that is, the flight distance of the droplets. Therefore, the flight distance of the droplet should be shortened unless a large deformation such as a spheroid is given.

On the other hand, when the droplets are charged with the same sign, they repel each other to form a large spread group of droplets. These droplets are attracted to objects of opposite sign and grounded conductors. That is, the scattered droplets are easily attached to the container wall of the coagulant and the electrode for giving an electric charge.
These become obstacles such as non-uniform particles and weakening of the electric field. However, if a conductive coagulant is placed in a metal container and this container is grounded, all the droplets can be drawn into the coagulant.

Although spherical uniform polymer particles are obtained as described above, various post-treatments may be added to improve these particles according to the purpose of use. In particular, the heating treatment in a non-solvent is useful for making the particle structure more stable.

The polymers which can be used in the present invention are all those which are soluble in a solvent, but examples of particularly useful ones are shown below.

Polystyrene has a small pressure loss and is useful as a packing material for chromatography in which fine particles are not mixed, or as an adsorbent having a small pressure loss and causing no minute polymer scraps and having excellent selectivity.

Further, a polymer such as a styrene-butadiene copolymer or a styrene-chloromethylated styrene copolymer capable of introducing a crosslink and an ion exchange group has a small pressure loss, has a large ion exchange rate and does not generate minute polymer scraps. It is useful as a base material for ion exchange resins.

Further, polyvinyl alcohol and ethylene-vinyl alcohol copolymer have active hydroxyl groups and have a small pressure loss, and are useful as a carrier having excellent selectivity for affinity chromatography.

Also, various natural polymer materials such as cellulose, silk,
Collagen and the like and derivatives thereof are also useful as they are for chromatography or as carriers for affinity chromatography.

Many other vinyl polymers, condensation polymers, can be used for the above applications.

Solvents for these polymer solutions can be found in handbooks such as J. Brandr.
up, polymer Handbook, 2nd edition, John wiley and
As can be seen from Sons, Inc. 1975, etc., a preferable coagulant is an aqueous solution as described later, and therefore a water-soluble solvent is preferable in order to make them compatible. N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulfoxide, diacetone alcohol, acetone, tetrahydrofuran,
Dioxane and the like can be used as a solvent for many polymer solutions. It is also possible to use a mixed solvent thereof or a mixed solvent obtained by adding ethanol, methanol, ethylene glycol, propylene glycol, glycerin or the like to these. In addition, extractable components, for example water-soluble polymers such as polyethylene glycol, polyvinylpyrrolidone, can be added to adjust the porosity of the particles.

The solvent for cellulose is a known mixed solvent of dimethyl sulfoxide and formaldehyde, an aqueous solution of copper ammonia,
An aqueous solution of calcium thiocyanate or the like can be used.

An appropriate solvent may be selected according to the type of other polymer.

The surface tension of the coagulant is similar to or lower than the surface tension of the solvent of the polymer solution as described above, and the coagulant is preferably conductive as described above. As such a coagulant, water containing a surfactant, an aqueous alcohol solution, an aqueous solution of the above-mentioned solvent, or a mixed solution thereof is particularly preferable for adjusting the fine structure of the obtained polymer particles according to the purpose of use. .

Thus, the production method of the present invention makes it possible to easily and inexpensively obtain spherical uniform polymer particles from which various polymer natural substances are produced without generating polymer scraps.

Hereinafter, the production method of the present invention will be described based on Examples, but the present invention is not limited to these Examples.

Example 1 The concentration of cellulose acetate (acetylation degree 55%) was 5% (% by weight,
The same shall apply hereinafter) to prepare a polymer solution by dissolving N-methyl-2-pyrrolidone and propylene glycol in a mixed liquid in which a weight ratio of 4 to 6 was mixed. The viscosity of this solution was 78 cP at 90 ° C. Also, the surface tension of the mixed solvent is calculated by the arithmetic mean of the values of each solvent at 25 ° C.
It was 38 dym / cm.

Using this device, a 5 mm hole with a diameter of 50 μm was prepared.
Nozzle having two openings (12) arranged linearly at intervals
It was ejected from (5). Here, from the tip of the vibrating rod (6) to the nozzle
The distance to (5) is 15 mm and the temperature of the polymer solution is 90 ° C.
The vibration frequency of the vibrating rod (6) connected to the magnetostrictive element at 25 KHz.
The flow velocity of the jet was set to 18 m / sec and synchronized so that uniform droplets could be formed.

A parallel plate electrode having a width of 20 mm and a distance between parallel plates of 10 mm is placed at a position of about 2 mm from the lower surface of the nozzle (5) parallel to the direction of the opening (12), that is, parallel to the direction in which the liquid droplets flow, and the cylinder is formed. Applied a voltage of 500V between. The cylinder was grounded.

A grounded stainless steel cylindrical container having a diameter of about 40 cm containing the coagulant was placed directly under the nozzle (5), and the distance from the nozzle to the coagulant was 40 cm. A 40% aqueous ethanol solution was used as a coagulant at room temperature. The surface tension of this solution is 32 at 25 ° C.
It was dym / cm.

The particles obtained were spherical and did not generate fine polymer debris even when stirred for a long time with a magnetic stirrer.

Suspend these particles in water to get 44μm, 63μm, 74μm 88μ
m, 105 μm, 125 μm, and 149 μm were classified by a wet sieve, and the particles collected on each sieve were suspended in water and allowed to stand for a day and night, and then the sedimentation volume was measured. The volume average particle diameter of the obtained particles was 111 μm, and 97% by volume or more of particles were within ± 20% of the volume average particle diameter. In addition, particles smaller than 44 μm could not be confirmed.

Example 2 6: 4 of dimethyl sulfoxide and propylene glycol so that the concentration of cellulose acetate with an acetylation degree of 61.5% was 5%.
Homogeneous polymer particles were obtained in the same manner as in Example 1 except that a polymer solution was prepared by dissolving in a mixed solution, and a 0.2% aqueous solution of household detergent (Lunamild manufactured by Kao Corporation) was used as a coagulating solution. . The viscosity of the polymer solution was 52 cP at 90 ° C.
The surface tension of this mixed solution was 39 dym / cm when calculated by the arithmetic mean of the values of the respective solvents at 25 ° C. The surface tension of the coagulant was 20 dym / cm at 25 ℃.

The particles were heated in a water bath at 120 ° C for 30 minutes. This treatment caused the particles to shrink uniformly by approximately 20%.

The obtained particles were spherical and did not generate fine orimarks even after being stirred with a magnetic stirrer for a long time.

The particles were classified by a wet sieve and the particle size distribution was measured in the same manner as in the Example. The obtained particles had a volume average particle size of 103 μm.
97% by volume or more of particles were within ± 20% of the volume average particle size. In addition, particles smaller than 44 μm could not be confirmed.

Example 3 7% polystyrene was dissolved in N-methyl-2-pyrrolidone to prepare a polymer solution. The viscosity of this solution is 250c at 90 ℃
It was P. The surface tension of this solvent is 41 dym / at 25 ° C.
It was cm. Using this solution, uniform polymer particles were obtained in the same manner as in Example 2.

The particles obtained were spherical and did not generate fine polymer debris even when stirred for a long time with a magnetic stirrer.

The particles were classified by a wet sieve in the same manner as in Example 1 and the particle size distribution of the particles was determined. The volume average particle size of the obtained particles was 1
At 16 μm, 97% by volume or more of particles were within ± 20% of the volume average particle size. In addition, particles smaller than 44 μm could not be confirmed.

Example 4 A polymer solution was prepared by dissolving an aqueous solution containing 60% of calcium thiocyanate as a component so that the concentration of cellulose was 4%. The viscosity of this solution was 420 cP at 100 ° C. The surface tension of this solvent was 73 dym / cm at 25 ° C. Using this polymer solution, the coagulation liquid is ethanol 50
% Aqueous solution, the distance from the tip of the vibrating rod (6) to the nozzle (5) in the apparatus of FIG. 1 was 5 mm, and the temperature of the polymer solution was kept at 100 ° C. Polymer particles were obtained. Surface tension of coagulating liquid is 30 at 25 ℃
It was dym / cm.

The particles obtained were spherical and did not generate fine polymer debris even when stirred for a long time with a magnetic stirrer.

When the particles were classified by a wet sieve and the particle size distribution was measured in the same manner as in Example 1, the volume average particle size of the obtained particles was 112 μm, and the volume average particle size was within ± 20% of 97% by volume or more. There were particles. In addition, particles smaller than 44 μm could not be confirmed.

In the above examples, a nozzle having an aperture (12) with a diameter of 50 μm was used, but the diameter of the droplet was changed by changing the diameter and forming uniform droplets of the polymer solution under the corresponding tuning conditions. 1000 μm corresponding to the intended use of particles
Hereafter, those having a narrow range of particle size distribution of 500 μm or less or 250 μm or less can be suitably obtained.

〔The invention's effect〕

The polymer particles easily obtained by the production method of the present invention are spherical uniform polymer particles having a narrow particle size distribution in which minute polymer scraps do not occur, so that the pressure loss is small,
Widely applicable to base materials of ion exchange resins with high ion exchange rate, adsorbents with low pressure loss and excellent selectivity and high adsorption rate, chromatography packing materials with low pressure loss and no flow of minute polymer waste. can do.

[Brief description of drawings]

FIG. 1 shows a polymer droplet manufacturing apparatus used in an embodiment of the present invention. (Main symbols in the drawing) (5): Nozzle (6): Vibrating rod (9): Liquid inlet (12): Opening

Claims (9)

[Claims] 1. A polymer solution is allowed to flow out of an opening at a constant flow rate, and vibration from a vibration source is applied to the solution so that a constant periodic turbulence is applied to the solution, and a uniform charge having the same sign is applied. After being jetted into the gas phase as droplets, a flight distance of 30 cm or more is allowed to elapse, then a non-solvent of the polymer contained in the polymer solution and exhibiting compatibility with the solvent of the polymer solution, and A method for producing uniform polymer particles, which comprises infiltrating a coagulant having a surface tension equal to or lower than the surface tension of the solvent of the polymer solution. 2. The production method according to claim 1, wherein the viscosity of the polymer solution is 10 to 2000 cP. 3. The method according to claim 1, wherein the frequency of the constant periodic turbulence added to the polymer solution is 1000 to 40,000 Hz. 4. The production method according to claim 1, wherein the vibration from the vibration source applied to the polymer solution is a vibration having a frequency of 3000 to 40,000 Hz. 5. The production method according to claim 1, wherein the solvent of the polymer solution has water solubility. 6. The manufacturing method according to claim 1, wherein the diameter of the droplet is 1000 μm or less. 7. The manufacturing method according to claim 1, wherein the diameter of the droplet is 250 μm or less. 8. The manufacturing method according to claim 1, wherein the coagulant has conductivity. 9. The method according to claim 1, wherein the coagulant is an aqueous solution.
The manufacturing method according to the item.