JPH06102730B2 - Bimodal particles for separation materials - Google Patents

Description

TECHNICAL FIELD The present invention relates to bimodal particles for a separating material. More specifically, the present invention relates to bimodal particles for a separation material that can be suitably used for chromatography, adsorbents and the like.

[Problems to be Solved by Conventional Techniques and Inventions] Conventionally, polymer particles have been used as a separating material such as a packing material for chromatography, a carrier for immobilizing an enzyme, a carrier for affinity chromatography, and a base material for an ion exchange resin. It is used.

Such polymer particles are mainly produced by a dispersion method or a spray method.

The dispersion method is solidified by volatilizing the solvent from a dilute solution of the polymer dispersed in the form of droplets in a dispersion medium containing a surfactant (see JP-A-56-24430).
This is a method of obtaining polymer particles by gradually adding a small amount of a coagulant to this dispersion to solidify it (see JP-A-57-159801). Although particles having a wide particle size distribution can be obtained by this method, washing with not only water but an organic solvent is necessary to remove the solvent, the dispersion medium and the surfactant from the solidified droplets.

Another method known as a dispersion method is a method in which a polymerizable monomer is dispersed in a dispersion medium and then polymerized to obtain polymer particles, and the particles obtained by such a method also have a wide particle size distribution. There is. However, when observing the particles with an electron microscope, it can be seen that finer spherical particles aggregate to form particles, and this structure seems to be the cause. When the suspension of (1) is stirred with a magnetic stirrer or the like, there is a drawback that a large amount of fine 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 (Japanese Patent Laid-Open No. 52-129).
(See Japanese Patent No. 788). However, when many polymer particles having a small particle size are included, pressure loss increases when used as a column-shaped adsorbent having good adsorption efficiency,
In particular, when it is used for the purpose of selectively removing plasma proteins and the like from blood, problems such as hemolysis occur, and the molecular weight cut-off is not sharp, resulting in poor selectivity.

If the particle size of the polymer particles is increased in order to improve the above-mentioned problem related to pressure loss, the specific surface area (total surface area of particles per unit volume) becomes small, and there is a drawback that the adsorption rate decreases.

Although polymer particles having a narrow particle size distribution and few problems as described above have also been produced (Japanese Patent Laid-Open No. 57-102905), these particles are not particles having a three-dimensional network structure, and are fine particles. It is a particle in which primary particles are aggregated, its mechanical strength is not always sufficient, and when it is used as, for example, a column-shaped adsorbent, uneven packing density and dispersion state occur, and so-called short path occurs during liquid injection. It has the drawback of occurring.

[Means for Solving the Problem] In view of the above-mentioned conventional technique, the present inventor does not cause short paths due to uneven filling even when used as, for example, a column-shaped adsorbent, and causes a pressure loss. As a result of earnestly researching small particles as much as possible, surprisingly, when bimodal particles for a separating material formed by mixing two kinds of particles having a specific particle size distribution in a specific ratio are used, The inventors have found that all the requirements are satisfied, and have completed the present invention.

That is, the present invention has a number average particle size of 10 to 1000 μm, respectively.
Is a particle mixture obtained by dispersing and mixing two types of monodisperse particles A and B within the range of
Are cellulose-based polymer, silk-based polymer, chitin-based polymer, acrylonitrile-based polymer, (meth)
It is an acrylate-based polymer, a styrene-based polymer, a vinyl alcohol-based polymer or a condensation-based polymer, and the ratio of the number average particle size of the monodisperse particles A and B is 0.5 / 1 to 0.9 / 1. The present invention relates to a bimodal particle for a separating material, which has a number ratio of 1/9 to 9/1.

[Examples] The bimodal particles for separating material of the present invention are particle-bonded products obtained by dispersing and mixing two types of monodisperse particles A and B.

Here, the monodisperse particles referred to in the detailed text of the present invention are particles in which 95% or more of the particles are within ± 10% of the number average particle diameter.

Specific examples of the polymer constituting the monodisperse particles used in the present invention include cellulose-based polymers such as cellulose, cellulose derivatives, and regenerated cellulose; silk-based polymers such as silk fibroin; chitin-based polymers such as chitosan; polyacrylonitrile, acrylonitrile. -Acrylonitrile-based polymers such as vinyl sulfonic acid copolymers; (meth) acrylate-based polymers such as polymethylmethacrylate, methylmethacrylate-hydroxyethylmethacrylate copolymer, polymethylmethacrylate stereocomplex, hydroxyethylmethacrylate-styrene copolymer, etc. Polymer; polystyrene, styrene-styrene copolymer such as styrene-butadiene copolymer, styrene-chloromethylstyrene copolymer; polyvinyl alcohol, ethylene-bi Vinyl alcohol-based polymer such as alcohol copolymer; or other polyamides,
Examples thereof include condensation type polymers such as polyamino acids, polyesters, polyethers, polyurethanes and polysulfones.

When the polymer constituting the monodisperse particles is, for example, a cellulosic polymer, it has characteristics such that nonspecific adsorption of blood cell components and plasma proteins is relatively small, and thus plasma proteins and the like are selectively extracted from blood. There are obtained particles that can be suitably used for applications such as removal. Further, as a polymer constituting the monodisperse particles, a polymer capable of introducing or cross-linking another group such as a styrene-butadiene copolymer or a styrene-chloromethylstyrene copolymer, for example, an ion-exchange group. When used, the monomolecular particles are suitable as a base material for ion exchange resins, particles with high mechanical strength, base materials for ion exchange resins with high mechanical strength, and separation materials such as carriers for affinity chromatography. Can be used. Further, when a polymer having an active hydroxyl group such as polyvinyl alcohol or ethylene-vinyl alcohol copolymer is used, it can be used as a separating material such as a carrier for affinity chromatography having a small pressure loss.

The polymer particles of the present invention are spherical particles (which is a concept that includes not only substantially spherical particles but also rotators having an elliptical shape with a minor axis / major axis up to about 0.8) and a number average particle diameter. (In the case of an elliptical rotating body, the volume average particle diameter, that is, it is calculated as the cube root of the value obtained by multiplying the square of the long diameter by the short diameter)
~ 1000 μm, preferably in the range of 50-600 μm, 9
5% or more of the particles are within the number average particle size ± 10%.

When the number average particle size is less than 10 μm, pressure loss becomes large when used as monodisperse particles for an adsorbent for selectively removing plasma proteins from blood, and protein denaturation easily occurs. It is easy to cause problems such as If it exceeds 1000 μm, the specific surface area becomes small and the adsorption rate becomes slow.

Further, when the ratio of particles within the number average particle diameter ± 10% is less than 95%, when used as an adsorbent for the adsorbent as described above, the pressure loss becomes large, and hemolysis is increased. May be more likely to occur.

The state of the surface of the monodisperse particles used in the present invention is not particularly limited, and a skin layer may be present or may have a network structure, and an intermediate state between the skin layer and the network structure. May be It is desirable that the inside has a three-dimensional network structure.

The three-dimensional network structure is a polymer (aggregate) of finer particles obtained by polymerizing droplets of a polymerizable monomer as described above, while it is a perforated surface like a sponge literally. Indicates a tissue body having a three-dimensionally continuous structure or a three-dimensionally continuous fiber structure.

The size and porosity of the mesh forming the three-dimensional network inside the monodisperse particles are not particularly limited, but the size of the mesh is preferably about 0.1 to 10 μm, and the internal diameter is It may have a hollow portion locally exceeding 10 μm. The porosity is preferably about 50 to 95%.

When the size of the mesh of the mesh structure is less than 0.1 μm, not only the adsorbing speed of the unwanted substances in blood decreases when used as an adsorbent for an adsorbent, but also the adsorptive removal of these unwanted substances. Is not performed sufficiently. On the other hand, if it exceeds 10 μm, the mechanical strength of the particles becomes insufficient, and the particles tend to be deformed or crushed during packing into the column or during transportation.

When a skin layer is present on the surface of the monodisperse particles, the thickness of the skin layer is usually about 0.1 to 10 μm. Thus, the monodisperse particles having a skin layer on the surface of the particle have a relatively small pore size on the surface, and thus can be suitably used as a chromatography particle having an exclusion limit molecular weight of about 1,000,000 or less or a base material for an ion exchange resin. .

When the surface of the monodisperse particles has a network structure, pores having a pore diameter of about 0.01 to 5 μm are usually present on the surface. When the particle surface has a network structure as described above, it becomes suitable as a carrier for chromatography particles having an exclusion limit molecular weight of about 1,000,000 or more or an immobilized enzyme.

The bimodal particles for the separating agent of the present invention are the same as those mentioned above.
This is a particle mixture in which types of monodisperse particles A and B are dispersed and mixed.

The ratio of the number average particle size of the monodisperse particles A and B is 0.5 /
Those adjusted to 1 to 0.9 / 1, especially 0.6 / 1 to 0.8 / 1 are used. When the ratio is smaller than 0.5 / 1, for example, the difference in sedimentation velocity is large, and therefore the respective particles tend not to be uniformly dispersed, and the pressure loss also increases. If it exceeds 0.9 / 1, the effect of preventing the occurrence of short paths tends to be poor. Further, the number ratio of the monodisperse particles A and B is adjusted to be 1/9 to 9/1, especially 2/8 to 8/2. When such a ratio is smaller than 1/9 or exceeds 9/1, there is no difference between the characteristics of each monodisperse particle when it is alone, and the effect of preventing the occurrence of short paths tends to be poor. is there.

In use, it is desirable that the two types of monodisperse particles are premixed so as to be uniformly dispersed in each other. If they are not uniformly dispersed, the characteristics of each monodisperse particle are independent. In some cases, the effect of preventing the occurrence of a short path becomes poor, and the pressure loss may increase.

Next, the case where a cellulosic polymer is used as the monodisperse particles used in the present invention will be described.

The cellulosic particles, which are one kind of monodisperse particles used in the present invention, are prepared by dissolving a cellulosic solution in which cellulose, a cellulose derivative or the like is dissolved, for example, the apparatus and method (vibration method) described in JP-A-62-191033. And a dry-wet coagulation method) are applied.

The solvent used when preparing the cellulose-based solution is a solvent for cellulose, such as an aqueous solution of copper ammonia, a mixed solution of dimethylsulfoxide and paraformaldehyde, an aqueous solution of calcium thiocyanate, and acetic acid which is a typical cellulose derivative. Examples of the solvent for cellulose include dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, and acetone.

In these solvents, whether or not a skin layer is formed on the surface of the obtained cellulosic particles, what is the thickness of the skin layer when it is formed, and the size of the pores of the internal network structure In order to adjust the size,
Methanol, ethanol, ethylene glycol, propylene glycol, glycerin, water, inorganic salts, polyethylene glycol, polyvinylpyrrolidone, etc. may be added.

The cellulosic solution of about 5 to 20% (% by weight, the same applies hereinafter) prepared in this manner is disclosed in, for example, JP-A-62-191.
Using a device such as the one described in Japanese Patent No. 033, the droplets are ejected into the gas phase as small droplets of almost uniform size, and after being allowed to fly over a flight distance that does not cause large deformation due to collision with a coagulant, coagulation is performed. Contact with the agent. The cellulosic particles produced in this manner are substantially spherical particles.

The coagulant is composed of a non-solvent for the polymer, but it is preferable that the coagulant is soluble in the solvent forming the droplets and has a surface tension such that the droplets naturally wet. Specific examples of such a coagulant include water, a mixed liquid of water and the good solvent or non-solvent, a mixed liquid of water and a surfactant, and the like.

Generally, the concentration of the polymer in the polymer solution is high, the proportion of the non-solvent is low, and a skin layer can be formed by using a coagulating liquid with a strong coagulation force like water, and slowing the coagulation to make the polymer denser. By aggregating, the size of the network of the network structure inside the particles can be reduced.

In the above description, polymer particles were produced using a cellulosic polymer, but when using other polymers, a polymer solution prepared by dissolving the polymer in a suitable solvent as described above is used, and the non-solvent of the polymer is used. It can be used as a coagulating liquid to produce polymer particles in the same manner as described above.

Polymer solvents, non-solvents, and coagulants can be obtained, for example, from Chemical Handbook (edited by The Chemical Society of Japan, published by Maruzen Co., Ltd., 1984), Polymer Handbook (J Brand Wrap &
J. Brandrup & E.M.Immergu
t,) John Willy & Sons
Sons, eds., New York, 1975) and the like can be used.

If there is a site for introducing or cross-linking another group such as an ion-exchange group in the polymer particles obtained in this way, then if another group is introduced or cross-linked. Good.

The monodisperse particles thus obtained have a specific average particle size and a specific particle size distribution, and were obtained by adjusting two specific types of such monodisperse particles at a specific mixing ratio. The bimodal particles for a separation material of the present invention can be suitably used for applications such as a packing material for chromatographs, a carrier for immobilizing enzymes, a carrier for affinity chromatography, a base material for ion exchange resins, and the like. When used, the filling state becomes uniform, so that short paths do not occur, and the pressure loss, adsorption rate, and separation rate selectivity are excellent.

Next, the bimodal particles for separating material of the present invention will be explained in detail based on examples, but the present invention is not limited to these examples. Production Example 1 Cellulose diacetate having a concentration of 12.5% Dimethyl sulfoxide / propylene glycol was dissolved in a mixed solution of 4/6 in weight ratio so that

5 cm in width at a distance of 2 cm at 5 mm in front of the nozzle,
A parallel plate electrode having a length of 25 cm in the droplet advancing direction was installed, and a DC voltage of 800 V was applied between the electrode and the nozzle. From the orifice with a diameter of 250 μm installed in this nozzle, the solution kept at 145 ° C. was flown at a linear velocity of 7.8 m / sec.
Discharge while applying vibration of 0 Hz, form uniform droplets of the solution, and fly in air for about 3 m, then at 10% of 23 ° C.
The particles were infiltrated into an aqueous methanol solution and solidified to obtain cellulose diacetate particles.

The obtained cellulose diacetate particles are put into a 0.6% caustic soda aqueous solution at 50 ° C., stirred for 2 hours, recovered, neutralized and washed with water to obtain almost 100% regenerated cellulose particles (monodisperse particles B). I got it.

When the number average particle size of the obtained regenerated cellulose particles was measured by the following method, it was 430 μm, and all the particles were within the average particle size ± 5%.

After replacing the liquid in the obtained regenerated cellulose particles with ethanol, a critical point dryer (HCP- manufactured by Hitachi, Ltd.)
2) was used for drying, gold was vapor deposited and then observed with a scanning electron microscope. As a result, there was a skin layer with a thickness of about 0.2 μm on the surface and a porous three-dimensional network with a pore size of about 0.2-2 μm inside. It was a tissue.

The regenerated cellulose particles were packed in a column having an inner diameter of 14 mm and a length of 7 cm, and a 44% aqueous glycerin solution (viscosity 4 cP, 24 ° C.)
, The pressure loss when flowing at a linear velocity of 20 cm / min
It was 52 mmHg. (Number Average Particle Size and Particle Size Distribution) An optical microscope image of several hundred particles (about 500 to 1000 particles) is processed and obtained using an image processing device (Luzex II manufactured by Nireco Co., Ltd.).

Production Example 2 In Production Example 1, the electrode length was 5 cm and the applied voltage was 510.
V, orifice hole diameter 100 μm, solution discharge linear velocity 8.9 m
Regenerated cellulose particles (mono-dispersed particles A) were obtained in the same manner as in Production Example 1 except that / sec, the frequency was 5000 Hz, and the flight distance was 1.7 m.

When the number average particle size of the obtained regenerated cellulose particles was measured in the same manner as in Production Example 1, it was 270 μm, and all the particles were within the average particle size ± 5%.

Next, when the pressure loss was measured in the same manner as in Production Example 1, it was 135 mmHg.

Examples 1 to 3 The particles obtained in Production Example 1 and Production Example 2 were adjusted to a predetermined mixing ratio, mixed in a beaker containing excess water, and allowed to settle. Soak up in the same cylindrical container used in Production Example 1,
The pressure loss was measured in the same manner as in Production Example 1. The results are shown in Table 1.

Next, the particles obtained in Production Example 1, Production Example 2 and Examples 1 to 3 were each packed in a column, and the column was filled with 10 cm / m 2.
The state of the tip of the 44% glycerin aqueous solution colored red with ink was visually observed at a speed of in. Compared with the case of using the particles obtained in Production Examples 1 and 2,
When the particles obtained in 3 were used, the tip of the aqueous glycerin solution was uniform.

[Effects of the Invention] The bimodal particles for a separating material of the present invention are a particle mixture obtained by dispersing and mixing two kinds of monodisperse particles having a specific number average particle size and a specific particle size distribution, for example for chromatography. When used as a packing material, a carrier for enzyme immobilization, a carrier for affinity chromatography, a base material for ion exchange resins, etc., the packing state is uniform, so short paths do not occur and separation Alternatively, there is an effect that the adsorption rate is increased and the pressure loss is reduced.

Claims (1)

[Claims] 1. A particle mixture obtained by dispersing and mixing two kinds of monodisperse particles A and B each having a number average particle diameter within the range of 10 to 1000 μm, wherein the monodisperse particles A and B are each a cellulosic polymer. , A silk-based polymer, a chitin-based polymer, an acrylonitrile-based polymer, a (meth) acrylate-based polymer, a styrene-based polymer, a vinyl alcohol-based polymer or a condensation-based polymer, and the ratio of the number average particle size of the monodisperse particles A and B is 0.5. Bimodal particles for separating material, characterized in that the number ratio of monodisperse particles A and B is 1/9 to 0.9 / 1 and 1/9 to 9/1.