JPS63117039A - Production of uniform polymer particle - Google Patents

Abstract

PURPOSE:To obtain uniform spherical polymer particles freed of fine polymer scraps, by injecting a polymer solution in the form of uniform liquid drops with charges of the same sign into a gas phase at a constant rate from an opening while applying thereto a particular periodic disturbance and introducing the liquid drops into a specified coagulant after a suitable flight range. CONSTITUTION:A polymer solution in the form of uniform liquid drops with charges of the same sign is injected into a gas phase at a constant rate from an opening while a particular periodic disturbance is applied thereto and then introduced into a coagulant after a flight range not causing marked collisional deformation of the drops. A preferable coagulant in one which is a nonsolvent for the polymer in said polymer solution, is compatible with the solvent in this polymer solution and has such as surface tension as to be spontaneously wetted with the liquid drops. It is preferable that the coagulant has a surface tension lower than the surface tension of the solvent in the polymer solution and is electroconductive. The frequency of said particular disturbance applied to the polymer solution is about 1,000-40,000Hz.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing uniform polymer particles having uniform particle size. For more details, please refer to 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 filler for chromatography, a carrier for enzyme immobilization, a carrier for affinity chromatography, and as a raw material for foams.

[Prior Art] Dispersion methods and spray methods are known as methods for producing spherical (hereinafter, spheroidal) polymer particles.

In the dispersion method, a dilute solution of a polymer dispersed in small droplets in a dispersion medium containing a surfactant is solidified by evaporating the solvent (see Japanese Patent Application Laid-Open No. 58-24430), or this dispersion is The polymer particles can be changed by gradually adding small droplets of a coagulant to the polymer and solidifying it (see Japanese Patent Application Laid-Open No. 159801/1983). This method makes it possible to obtain particles with a wide particle size distribution. This method also requires washing with not only water but also organic solvents to remove the solvent, dispersion medium, and surfactant from the solidified droplets.

Another known method of dispersion is to obtain polymer particles by dispersing a polymerizable monomer in a dispersion medium and then polymerizing it, and the particles obtained by this method also have a wide particle size distribution. There is. When these particles are observed under magnification using an electron microscope, it can be seen that even smaller spherical particles are aggregated to form particles. This structure is thought to be the cause, but when a suspension of particles obtained by this method is stirred using a magnetic cooler, a large amount of tiny polymer debris is produced.

In the spray method, polymer particles are changed by spraying a polymer solution into a coagulant.

These particles also have a wide particle size distribution and are relatively large in size (see Japanese Patent Laid-Open No. 129788/1983).

In recent years, a technique (hereinafter referred to as the vibration method) has been discovered in which uniform droplets are obtained by periodically imparting turbulence to a jet flow having a constant flow rate.

Uniform polymer particles have been successfully obtained by applying this technique to a manufacturing method using a dispersion method of polymerizable monomers (see Japanese Patent Laid-Open No. 102905/1983).

However, as pointed out above, these particles have the disadvantage that polymer waste is likely to be generated.

There are examples of polymer particles and capsules being made from polymer solutions by applying the vibration method (see JP-A-52-1296813 and JP-A-59-112833), but JP-A-52-129686 In the example disclosed in JP-A-59-112833, a very dilute solution of the polymer, and therefore a low viscosity solution, is used, and in the example disclosed in JP-A-59-112833, the nozzle itself is directly vibrated, so the vibration frequency is small. particles with a limited and large particle size are produced.

In each example, multiple tubular nozzles are used to eject two or more types of solutions simultaneously while maintaining a delicate balance.

[Problems to be Solved by the Invention] As mentioned above, the conventional technology has the disadvantage that the particle size distribution of the polymer particles is wide or that polymer particles with minute polymer particles are generated, and furthermore, when producing such polymer particles, The disadvantage of this method is that it uses complicated equipment such as multiple tubular nozzles and requires delicate operation.

An object of the present invention is to eliminate these drawbacks and provide a method for producing uniform polymer particles that can easily form spherical uniform polymer particles that do not generate minute polymer debris.

[Means for Solving the Problems] The present inventors have found that these problems can be solved by the following manufacturing method. In other words, a polymer solution is ejected into the gas phase as uniform droplets with the same electric charge at a constant flow rate while applying a constant periodic turbulence from an opening, and then the droplets undergo large deformations due to collisions. The droplets are then allowed to fly over a flight distance that does not cause the droplets to drop, and then placed in a coagulant that is a non-solvent for the polymer of the polymer solution, exhibits compatibility with the solvent of the polymer solution, and has a surface tension sufficient to naturally wet the droplets. The present inventors discovered that spherical, uniform polymer particles with a narrow particle size distribution without generating polymer waste can be obtained without using a complicated device such as a multi-tubular nozzle, and the present invention is based on the present invention. I was able to complete it.

[Example 2] The term spherical as used herein means a spheroidal shape having a smooth surface. In addition, uniform particles are J
Using an IS standard sieve, the particles are classified using a wet sieve containing water, alcohol, etc. as a dispersion liquid, and the particles caught on each node are collected, and after being left for day and night, the sedimentation volume of each is measured. Formula: (In the formula, Dl is the sieve opening, and Vt is the settling volume of particles caught on the sieve with opening DI.) Within the range of ±20% of the volume average particle diameter calculated from the formula: Preferably ±
This means that 80% by volume or more of the particles in the particle group are within the 10% range.

In addition, the presence or absence of minute particles of less than 5 particles and polymer waste,
Confirmed using a microscope or a Coulter counter (manufactured by Coulter Co., Ltd., Coulter Counter).

In order to obtain strong polymer particles that do not generate polymer waste, which is one of the objects of the present invention, the concentration of the polymer solution must be several percent by weight or more, although it depends on the molecular weight of the polymer. Depending on the measurement temperature, such a solution is 1
It is a solution of a relatively highly polymerized polymer having a viscosity of 0 cP or more, preferably 50 cP or more.

Further, if the viscosity of the solution exceeds 2000 cP, it becomes difficult to form droplets having a particle size of 1000 cP or less by the vibration method, so it is preferably 2000 cP or less.

In order to create uniform droplets by the vibration method, it is necessary to correlate the viscosity of the polymer solution, its surface tension, the flow rate of the jet, the diameter of the opening from which the droplets are ejected, and the frequency and displacement of periodic turbulence. (T, 5akai, P
roc.

(See IcLAss-1982, p37.1982).

If the droplet diameter exceeds 1,000 degrees, synchronization can also be achieved by directly mechanically vibrating the aperture (see the above-mentioned document). However, as the diameter of the droplet decreases, the tuned frequency increases, and a large amount of energy is required to directly vibrate the opening, so a method of directly applying periodic disturbance to the solution is preferred. Especially when the droplet diameter is 2
50- or less, the inventors' earlier application (Japanese Patent Application No. 8
1-24591), the tuning frequency is 3000 to 40000 Hz.

FIG. 1 shows an apparatus for obtaining such droplets.

In FIG. 1, the vibrating rod (6) is connected to a suitable vibration source, for example a magnetostrictive element, an electrostrictive element or an electromagnetic coil vibrator. In order to efficiently transmit this vibrational energy to the vibrating rod (6), it is preferable to use an O-ring (7) with low contact resistance for sealing with the cylinder (2).A nozzle having an opening 02. (5) and the tip of the vibration rod (6) is the cylinder ('2J screw 0
1) and the cylinder fixing nut (4). The nozzle (5) is fixed to the cylinder (2) by a nozzle fixing nut (3). Nozzle (!5)
The space between the cylinder (2) and the cylinder (2) is sealed with an O-ring (8). The cylinder (2) is fixed to the fixed base (1) by a cylinder fixing nut (4).

The polymer solution sent from a gear pump etc.
) enters the cylinder [21] and is ejected from the opening 02) while undergoing periodic pressure changes due to the reciprocating motion of the vibrating rod (6) on the nozzle (5). If necessary, it is also possible to heat the polymer solution in the cylinder (2) with a heater °C. The temperature sensor 0Φ is therefore also used for temperature control.

The distance between the nozzle (5) and the tip of the vibrating rod (6) is preferably 5 cm or more, especially when the vibration frequency is high enough to be included in the ultrasonic range.

If this distance is less than 2 mm, cavitation may occur and the tip of the vibrating rod (6) and the inner surface of the nozzle (5) may be eroded.

If necessary, in order to maintain the frequency more stably, a cooling water inlet/outlet may be provided in the fixed base (1).

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

Once formed, uniform droplets move away from the nozzle (5) and begin to move erratically due to air resistance, and many droplets collide with each other and coalesce. However, J.H. Schneider and C.D. Hendricks, Review of Cynigistic Instruments, Vol. 35, p. 1349, 19
1964 (J, H, 5hnelder and C, D,
Hendricks, Review of 5th Century
tific 1nstrua+entss 35.13
49.19B4), this coalescence can be prevented for a relatively long time by charging each droplet with an electric charge of the same sign.

The droplets of the polymer solution discharged into the gas phase as described above are solidified, being a non-solvent for the polymer, exhibiting compatibility with the solvent, and having a surface tension sufficient to naturally wet the droplets. After the particles have traveled a distance longer than the flight distance required to stall to a speed that does not cause large deformation due to collisions, they are allowed to penetrate into the particles, forming uniform spherical polymer particles.

If the surface tension of the coagulant is greater than that of the solvent in the polymer solution and does not spontaneously wet the droplet, the droplet will remain on the coagulant surface for a long time even if the specific gravity of the droplet is greater than that of the coagulant. As it floats, new droplets collide on top of this droplet one after another, forming a large coalesced object. However, if a droplet that falls on the coagulant is quickly covered with the coagulant, it will not coalesce even if it collides with a new droplet, and this droplet will also be quickly covered with the coagulant.
Each droplet becomes an independent polymer particle. As a rough guide, such coagulants are selected from those having a surface tension approximating, but preferably less than, that of the solvent of the polymer solution.

As disclosed in the specification of the inventors' earlier application (Japanese Patent Application No. 61-24591), the flow rate of the polymer solution ejected from the opening becomes synchronized when the viscosity of the polymer solution is high and the droplet diameter becomes small. In other words, the initial velocity of the droplet reaches from several m7 seconds to several tens of m7 seconds, so if the droplet immediately enters the coagulation liquid, the impact of the collision will cause the particles to scatter or become flattened. In order to avoid this, it is necessary to reduce the flight speed of the droplets before they enter the coagulant.

As mentioned above, when droplets are charged with the same sign, it is possible to prevent the droplets from coalescing for a relatively long time, but the present inventors have discovered that another effect of charging the droplets with the same sign is that found that the droplet's flight speed suddenly stalled. In particular, droplets with a small particle size have a large initial synchronized velocity, and if they are not given a charge of the same sign, they may deform into a flattened shape even after a flight distance of 2 m when they enter the coagulant. By applying a charge of , the effect can be changed so that the same droplet can fly into the coagulation liquid without being deformed even if it travels a distance of 30 cm.

Further, it is important to minimize the distance from the opening to the coagulant, that is, the flight distance of the droplets, in order to prevent droplets from coalescing. Therefore, the flight distance of the droplet should be shortened unless it undergoes a large deformation that cannot be called a spheroid.

On the other hand, when droplets are charged with the same sign, they repel each other, forming a spread group of many droplets. These droplets are attracted to objects with oppositely charged charges or to grounded conductors. That is, the scattered droplets tend to adhere to the wall of the coagulant container or the electrode for applying electric charge.

These become obstacles such as becoming non-uniform particles and weakening the force of the electric field. However, if the conductive coagulant is placed in a metal container and the container is grounded, all droplets will be drawn into the coagulant.

Although spherical uniform polymer particles can be obtained in the manner described above, various post-treatments can be applied to further modify these particles depending on the purpose of use. In particular, heating treatment in a non-solvent is useful for making the particle structure more stable.

All polymers that can be used in the present invention are those that are soluble in a solvent, but examples of particularly useful polymers are shown below.

Polystyrene is useful as a packing material for chromatography that has low pressure loss and does not contain fine particles, and is useful as an adsorbent that has low pressure loss, does not generate minute polymer debris, and has excellent selectivity.

In addition, polymers that can be crosslinked and have ion exchange groups, such as styrene-butadiene copolymers and styrene-chloromethylated styrene copolymers, have low pressure loss.
It has a high ion exchange rate and is useful as a base material for ion exchange resins that do not generate minute polymer waste.

Furthermore, polyvinyl alcohol and ethylene-vinyl alcohol copolymers have active hydroxyl groups, have low pressure loss, and are useful as carriers with excellent selectivity for affinity chromatography.

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

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

Solvents for these polymer solutions are listed in handbooks, e.g. J, Br
andrupx Polyller Handboo
k, 2ndeditlon% John Wlle
y and 5ons% Inc., 1975, etc., but as will be described later, the preferred coagulant is an aqueous solution, so a water-soluble solvent is preferred in order to have compatibility with these. N-methyl-
2-pyrrolidone, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, diacetone alcohol, acetone, tetrahydrofuran, dioxane, etc. can be used as solvents for many polymer solutions. In addition, these mixed solvents and these include ethanol, methanol, ethylene glycol, propylene glycol,
It is also possible to use a mixed solvent containing glycerin or the like.

Extractable components to further adjust particle porosity,
Water-soluble polymers such as polyethylene glycol, polyvinylpyrrolidone can also be added.

Solvents for cellulose include known mixed solvents of dimethyl sulfoxide and formaldehyde, aqueous copper ammonia solutions,
An aqueous solution of calcium thiocyanate or the like can be used.

In addition, an appropriate solvent may be selected depending on the type of polymer.

As described above, the surface tension of the coagulant is close to or lower than the surface tension of the solvent of the polymer solution, and the coagulant is preferably electrically conductive as described above. As such a coagulant, water to which a surfactant has been added, an aqueous alcohol solution, an aqueous solution of the above-mentioned solvent, or a mixture thereof are particularly preferred in order to adjust the fine structure of the resulting polymer particles depending on the purpose of use. .

Thus, by the production method of the present invention, uniform spherical polymer particles without polymer waste can be easily and inexpensively produced from various natural and synthetic polymeric substances.

Hereinafter, the manufacturing method of the present invention will be explained based on Examples, but the present invention is not limited only to these Examples.

Example 1 The concentration of cellulose acetate (degree of acetylation: 55%) was 5% (wt%).
A polymer solution was prepared by dissolving N-methyl-2-pyrrolidone and propylene glycol in a mixed solution in a weight ratio of 4:6 so that the following formula was obtained. The viscosity of this solution was 78 cP at 90°C. The surface tension of the mixed solvent was 38 dym/cw+ when determined by the arithmetic mean of the values of each solvent at 25°C.

This solution was prepared using the apparatus shown in Figure 1 to make 5 pores with a diameter of 50ρ.
It was ejected from a nozzle (5) having two openings (02) arranged in a straight line with an interval of mm. Here, the distance from the tip of the vibrating rod (6) to the nozzle (5) is 15 mm, the temperature of the polymer solution is maintained at 90°C, the frequency of the vibrating rod (6) connected to the magnetostrictive cord is 25 KHz, and the jet flow is The flow velocity of 18m
/ seconds and synchronized to form a uniform droplet.

Width 2 (1 mm) at a position approximately 2 dragons from the bottom of the nozzle (5).

Parallel plate electrodes with a distance between parallel plates of 10 +w were placed parallel to the opening, and a voltage of 500 V was applied between them and the cylinder. The cylinder was also grounded.

A grounded stainless steel cylindrical container with a diameter of approximately 40,011 mm containing a coagulant was placed directly below the nozzle (9), and the distance from the nozzle to the coagulant was 40 C1.A 40% aqueous ethanol solution was used as the coagulant at room temperature. The surface tension of this solution was 32 dyIII/an at 25°C.

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

Suspend these particles in water and
The particles were classified using wet sieves of 105, 125 and 149, and the particles collected in multiple tubes were suspended in water, -
After standing for day and night, the sedimentation volume was measured. The volume average particle size of the obtained particles was 111 items, and 97% by volume or more of particles were within the range of ±20% of the volume average particle size. In addition, no particles with a particle size of less than 44-mm were confirmed.

Example 2 Dimethyl sulfoxide and propylene glycol were mixed so that the concentration of cellulose acetate with acetylation degree of 61.5% was 5%.
Uniform polymer particles were prepared in the same manner as in Example 1, except that a 0.2% aqueous solution of household detergent (Luna Mild, manufactured by Kao ■) was used as the coagulation liquid. I got it. The viscosity of the polymer solution was 52 cP at 90°C. Also, the surface tension of this mixed solution is 2
The arithmetic mean of the values at 5°C was found to be 39 dym/unit. The surface tension of the coagulant was 20 dym/(to) at 25°C.

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

The obtained particles were perfectly spherical and did not generate minute polymer debris even when stirred for a long time in a Magnex cooler.

When the particles were classified using a wet sieve and the particle size distribution was measured in the same manner as in the example, the volume average particle size of the obtained particles was 103 mm.
More than 97% by volume of particles were within ±20% of the volume average particle size. Further, no particles with a particle size of less than 44 ta could be confirmed.

Example 3 A polymer solution was prepared by dissolving 7% polystyrene in N-methyl-2-pyrrolidone. The viscosity of this solution is 90℃
It was 250 cP. Also, the surface tension of this solvent is 2
It was 41 dym/cm at 5°C. Using this solution, uniform polymer particles were obtained in the same manner as in Example 2.

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

When the particles were classified using 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.
1B, there were more than 97% by volume of particles within ±20% of the volume average particle size.

Further, particles with less than 44 letters could not be confirmed.

Example 4 A polymer solution was prepared by dissolving calcium thiocyanate as a component in an aqueous solution containing 60% so that the cellulose concentration was 4%. The viscosity of this solution is 42 at 100°C.
It was 0 cP. The surface tension of this solvent is 73d at 25℃
)a+/(to). Using this polymer solution, a 50% ethanol aqueous solution was used as the coagulation liquid, the distance from the tip of the vibrating rod (6) to the nozzle (■) was set to 5 μms in the apparatus shown in Figure 1, and the temperature of the polymer solution was set to 100°C. Uniform polymer particles were obtained in the same manner as in Example 1, except that the particles were maintained.

The surface tension of the coagulating liquid is 30 d yra/c at 25°C
It was m.

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

When the particles were classified using a wet sieve in the same manner as in Example 1 and the particle size distribution was measured, the volume average particle size of the obtained particles was 112 mm, and 97% by volume or more was within ±20% of the volume average particle size. There were particles of In addition, no particles with a particle size of less than 44 mm could be confirmed.

In the above example, a nozzle with an opening a'2J having a diameter of 50 was used, but by changing this diameter and forming uniform droplets of the polymer solution under corresponding tuning conditions, the diameter of the droplet can be changed. 10 depending on the usage of polymer particles
Those having a narrow range of particle size distribution of 00 or less, 500 or less, or 250 or less can be suitably used.

〔Effect of the invention〕

The polymer particles easily obtained by the production method of the present invention are spherical, uniform polymer particles with a narrow particle size distribution that do not generate minute polymer waste, so they can be used as a matrix for ion exchange resins with low pressure loss and high ion exchange rate. It can be widely applied to materials, adsorbents with low pressure loss and excellent selectivity, and high adsorption speed, and chromatography packing materials with low pressure loss and no flow of minute polymer debris.

[Brief explanation of the drawing]

FIG. 1 shows a polymer droplet production apparatus used in an example of the present invention. (Main symbols in the drawing) (5): Nozzle (6): Vibrating rod (9): Liquid inlet 02): Opening

Claims (1)

[Claims] 1. After a polymer solution is ejected from an opening into a gas phase at a constant flow rate while adding a constant periodic turbulence as uniform droplets with the same sign of charge, large droplets due to collisions occur. The solidification is carried out over a flight distance that does not cause deformation, and then solidified, which is a non-solvent for the polymer of the polymer solution, is compatible with the solvent of the polymer solution, and has a surface tension sufficient to naturally wet the droplets. 1. A method for producing uniform polymer particles, the method comprising the step of infiltrating uniform polymer particles into an agent. 2. The manufacturing method according to claim 1, wherein the viscosity of the polymer solution is 10 to 2000 cP. 3. Claim 1, wherein the frequency of the constant periodic disturbance applied to the polymer solution is 1000 to 40000 Hz.
Manufacturing method described in section. 4. Claim 1, wherein the frequency of the constant periodic disturbance applied to the polymer solution is 3000 to 40000 Hz.
Manufacturing method described in section. 5. The manufacturing method according to claim 1, wherein the solvent of the polymer solution is water-soluble. 6. The manufacturing method according to claim 1, wherein the droplets have a diameter of 1000 μm or less. 7. The manufacturing method according to claim 1, wherein the droplets have a diameter of 250 μm or less. 8. The manufacturing method according to claim 1, wherein the surface tension of the coagulant is lower than the surface tension of the solvent of the polymer solution. 9. The manufacturing method according to claim 1, wherein the coagulant is electrically conductive. 10. The manufacturing method according to claim 1, wherein the coagulant is an aqueous solution.