JP3298191B2 - Method for producing porous polymer particles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing porous polymer particles, and more particularly, to a method for producing microporous polymer particles having a uniform particle diameter. The microporous polymer particles having a uniform particle size according to the present invention are particularly suitable for high-performance gel permeation chromatography (GPC) for separation and analysis of oligomers and polymers. Can be used as

[0002]

2. Description of the Related Art GPC uses a column filled with a porous packing material (hereinafter, referred to as gel), and allows a solution containing samples of various molecular sizes to pass through the column. This is a type of liquid chromatography to be eluted.

[0003] Conventionally, organic solvent-based GPC has been
Widely used in the field of polymer chemistry. As the organic solvent-based GPC, styrene-divinylbenzene-based copolymer particles having many characteristics are widely and generally used.

[0004]

In recent years, the development of high-performance GPC gels has been strongly demanded with the progress of high-speed analysis. To that end, high mechanical strength and uniform pores are required. In addition, spherical and uniform fine particles are required.

Until now, various studies have been made on a method for producing microporous polymer particles having a uniform particle diameter. As a method for producing polymer particles, a suspension polymerization method is known in which a polymerizable monomer, a crosslinkable monomer, or the like is dispersed in an aqueous solvent and particles formed are taken out of the system. Even if the optimal stirring conditions are determined, it is not possible to narrow the oil droplet distribution at the initial stage of polymerization, and it is difficult to obtain uniform and fine particles because the coalescence and splitting may lead to unevenness. was difficult.

As a method for solving this problem, a production method using a suspension stabilizer or a suspension stabilizing aid (Japanese Patent Laid-Open No. Sho 52-1454).
No. 89), a polymerization method in which aqueous suspension polymerization is performed under high-speed shearing and stirring (Japanese Patent Publication No. 62-45661), and a method in which suspension polymerization is performed while irradiating a monomer with ultrasonic waves (Japanese Patent Laid-Open No. 59-2193)
No. 03) has been proposed, but there are problems to be improved, such as a long process and low yield.

[0007] Seed polymerization method (Japanese Patent Application Laid-Open No. 61-225208)
Unlike the suspension polymerization method, the particles are made larger by absorbing and swelling the monomer into the seed particles, so that uniform particles can be obtained. . However, this method has a problem that the production process is complicated and requires a long time, and the pore distribution, porosity and mechanical strength are not sufficient.

[0008]

Means for Solving the Problems The present inventors have made intensive studies on a method for producing microporous polymer particles having a uniform particle size, which can be easily applied industrially and can be carried out at a high yield. It has been found that by injecting an organic phase through an inorganic film having pores with a uniform pore size, it is possible to prevent coalescence and splitting from occurring, and have completed the present invention.

That is, according to the present invention, an organic phase comprising a polymerizable monomer, a crosslinkable monomer, a non-reactive organic solvent and a polymerization initiator is mixed with an aqueous phase containing a dispersant and a surfactant to form a polymer having a uniform pore size. This is a method for producing porous polymer particles, wherein a uniform O / W emulsion is prepared by press-fitting through an inorganic film having pores, followed by polymerization. Hereinafter, the present invention will be described in detail. The coefficient of variation V used in this specification is represented by V = σ / x (where σ is a standard deviation (μm), and x is an arithmetic mean (μm )).

Examples of the polymerizable monomer include styrene derivatives such as styrene, ethylvinylbenzene, α-methylstyrene and chloromethylstyrene, methacrylates such as methyl methacrylate and ethyl methacrylate, methyl acrylate and ethyl acrylate. Acrylates, vinyl esters such as vinyl acetate, etc., and those capable of suspension polymerization such as acrylonitrile, and these may be used alone or in combination of two or more. In particular, styrene and ethylvinylbenzene are preferred polymerizable monomers in the present invention in terms of pore properties and the like.

The crosslinkable monomers include divinylbenzene (DVB), divinyltoluene, diacrylate or dimethacrylate of ethylene glycol, diacrylate or dimethacrylate of polyethylene glycol, and the like. One type or a combination of two or more types may be used. In the present invention, in particular, para- or meta-DV
B is preferred. In order to produce a gel having high mechanical strength, the proportion of the crosslinkable monomer in all the monomers (the sum of the polymerizable monomer and the crosslinkable monomer) is preferably 20 mol% or more.

The non-reactive organic solvent is not particularly limited as long as it is soluble in the polymerizable and crosslinkable monomers, insoluble in the copolymer thereof, and inactive. For example, aromatic hydrocarbons, aliphatic hydrocarbons, ketones, esters, alcohols and the like can be exemplified, and these can be used alone or in combination of two or more. In the present invention, toluene, dodecane or iso-amyl alcohol is particularly preferred. These solvents may be used in a range of 50 to 300% by volume based on all monomers.

Examples of the polymerization initiator include organic peroxides such as benzoyl peroxide (BPO) and lauryl peroxide, and azo compounds such as azobis-isobutyronitrile and azobisdimethylvaleronitrile (ADVN). These polymerization initiators are used in an amount of 0.05 to 5.0 based on all monomers.
It may be used in the range of weight%, but there is no particular problem if it exceeds this range.

Examples of the dispersant include poorly soluble phosphates such as calcium tertiary phosphate (TCP) and hydroxyapatite, and water-soluble polymers such as polyvinyl alcohol (PVA), carboxymethyl cellulose, and polyacrylamide. One or two or more of these may be used, but PVA is particularly preferred for efficiently producing fine and uniform porous polymer particles. When these dispersants are used in a large amount, they tend to cause non-uniformity and agglomeration of the produced particles, which tends to cause a decrease in yield, and conversely, when used in a small amount, the produced particles tend to be non-uniform. From the aqueous phase
It is preferable to use it in the range of 5 to 10.0%.

Examples of the surfactant include anionic surfactants such as sodium dodecyl sulfate (SDS) and sodium dodecylbenzenesulfonate (DBSNa), as well as nonionic surfactants and amphoteric surfactants. Anionic surfactants are preferred for efficient production of fine and uniform porous polymer particles.
Is particularly preferred. The surfactant is not more than the critical micelle concentration (CMC) specific to the one to be used, and is 0.01 to 1.0, preferably 0.1 to 0.5 as a concentration in the aqueous phase.
It is preferable to use it in the range of weight%.

The inorganic film is not limited as long as it has uniform pores, but a porous film is preferably used to improve the yield. The uniform pores in the present invention do not mean that the pore diameter of the membrane is completely uniform. More specifically, the properties of the preferred inorganic membrane are as follows: many pores having a uniform pore diameter, and naturally these pores penetrate the membrane, and when the organic phase is pressed into the aqueous phase, deformation and destruction occur. That it has mechanical strength to the extent that it does not occur, that it has chemical durability to the reagents in the organic phase or aqueous phase used, that any pore size can be selected,
It is. Here, the pore diameter of the inorganic film is 0.1 to 5.0.
The range of μm is preferred. Above all, a membrane having a pore diameter in the range of 0.2 to 3.0 μm is particularly preferable because the yield is good.

The pressure at the time of preparing an O / W emulsion by injecting the organic phase into the aqueous phase through the inorganic film and dispersing the organic phase to a desired diameter is applied to the inorganic film. There is no limitation as long as deformation or destruction does not occur. For example, the pressure is preferably in the range of 0.2 to 2.0 kgf / cm @ 2, and the emulsion preparation time is preferably in the range of about 30 minutes to 2 hours because of good operability.

After the above operation, polymerization is carried out. The polymerization may be carried out under ordinary conditions. For example, the operation may be performed in a temperature range of 50 to 100 ° C. for about 3 to 16 hours under normal pressure, increased pressure or reduced pressure.

In the present invention, when the porous polymer particles having a uniform particle diameter are more reliably produced, particularly when the organic phase is press-fitted into the aqueous phase through the inorganic film,
The aqueous phase is preferably stirred so that the oil droplets of the organic phase do not coalesce or split. The stirring conditions are, for example, 100 to 300 rpm, more preferably 13 rpm using a stirring blade.
Stirring at a rotation speed of 0 to 250 rpm is good. However, in the present invention, it is preferable to vibrate the aqueous phase more than stirring. There is no particular limitation on such a vibration method itself. For example, a method of irradiating an ultrasonic wave or a vibrating membrane emulsifying apparatus such as a commercially available mixer (for example, Vibromixer, manufactured by Reika Kogyo Co., Ltd.) is used. Vibration due to the reciprocating motion of the piston may be used. The higher the frequency, the better, but preferably 30
0 to 1500, more preferably 500 to 1000 rpm
Range.

[0020]

EXAMPLES The present invention will be described below in more detail with reference to Examples, but the present invention is not limited to these Examples. In the measurement of the average particle size and the particle size distribution of the gel in the present invention, the gel is collected on a preparation, dispersed in a 5% PVA aqueous solution, and analyzed with an optical microscope (BHT-MD manufactured by Olympus Optical Industries, Ltd.). After taking a photograph using the same, the photographing was performed using a digitizer (manufactured by Graphtec Co., Ltd.).

Example 1 The present invention was implemented using the apparatus shown in FIG. 1.50% by weight of TCP and 0.05% by weight of DBSNa in distilled water
In addition, it was dissolved and mixed to form an aqueous phase. Further, 2.02 mol / L of isooctane, 2.90 mol / L of styrene,
DVB 2.38mol / L, ADVN 0.20mo
The mixture was mixed at a ratio of 1 / L to obtain an organic phase. In the apparatus of FIG. 1, the aqueous phase is put into an aqueous phase tank (5), circulated by a circulation pump (4), and has a pore diameter of 1.10 μm as an inorganic membrane (1) fixed by a jacket (2). SPG
Using a membrane (manufactured by Asahi Glass Co., Ltd.), the organic phase is put into the membrane and into the organic phase tank (3), and the pressure gauge (7) is passed through the SPG membrane using nitrogen gas from a nitrogen cylinder (6). ) For 1 hour so that the pressure becomes 0.6 to 0.8 kgf / cm 2, and desorbed / dispersed from the pores of the SPG film into the aqueous phase to obtain O / W
A type emulsion was prepared.

The emulsion thus prepared was added to 8
After transferring to a polymerization reactor set to 0 ° C. and replacing with nitrogen gas, 132 rpm using two stainless steel blades
and polymerized for 8 hours. The obtained polymer particles were separated by filtration, washed with distilled water and ethyl alcohol in that order, and dried. The average particle size of the polymer particles was 9.56 μm, and the coefficient of variation was 0.37.

Example 2 The present invention was implemented using the apparatus shown in FIG. 1.00% by weight of PVA and 0.10% by weight of DBSNa in distilled water
In addition, it was dissolved and mixed to form an aqueous phase. Further, 2.02 mol / L of isooctane, 2.90 mol / L of styrene,
DVB 2.38mol / L, ADVN 0.20mo
The mixture was mixed at a ratio of 1 / L to obtain an organic phase. In the apparatus of FIG. 2, the organic phase is stored in an organic phase tank (5) in a pressurized tank (4).
And SP having a pore size of 1.10 μm as in Example 1
The G membrane (8) is placed in the aqueous phase tank (3), and the pressure of the pressure gauge (7) is set to 0.4 kgf / cm @ 2 through the membrane using nitrogen gas in a nitrogen cylinder (6). And pressurized for 1 hour so that the vibromixer (1)
Was removed and dispersed in an aqueous phase vibrated by a reciprocating motion of a piston (2) having a motor rotation speed of 662 rpm to prepare an O / W emulsion.

The emulsion thus prepared was mixed with 8
It was transferred to a polymerization reactor set at 0 ° C., replaced with nitrogen gas, and then subjected to 220 rpm using two stainless steel blades.
Polymerized at pm for 6 hours. The obtained polymer particles were separated by filtration, washed with distilled water and ethyl alcohol in that order, and dried. The average particle size of the polymer particles was 6.61 μm, and the coefficient of variation was 0.27.

Example 3 The same operation as in Example 2 was performed except that the surfactant in the aqueous phase was changed to SDS. The average particle size of the obtained polymer particles was 6.48 μm, The coefficient was 0.22.

Example 4 The same operation as in Example 3 was carried out except that the concentration of the surfactant SDS in the aqueous phase was changed to 0.20% by weight.
The average particle diameter of the obtained polymer particles was 6.36 μm, and the coefficient of variation was 0.18.

Example 5 The same operation as in Example 2 was performed except that the pore diameter of the SPG membrane was changed to 0.52 μm. The average particle diameter of the obtained polymer particles was 4.22 μm, Coefficient is 0.18
Met.

Example 6 The same operation as in Example 2 was carried out except that the pore size of the SPG membrane was changed to 3.00 μm, and the average particle size of the obtained polymer particles was 14.38 μm. Coefficient is 0.1
It was 7.

Example 7 The same operation as in Example 2 was performed except that the pore diameter of the SPG membrane was changed to 5.50 μm. The average particle diameter of the obtained polymer particles was 17.38 μm, Coefficient is 0.3
It was 0.

[0030]

As is clear from the above description, according to the production method of the present invention, the organic phase is brought into interface with the dispersant via the (preferably porous) inorganic film having pores of uniform pore size. An O / W emulsion is prepared by injecting into an aqueous phase containing an activator, and then the emulsion is polymerized to obtain a microporous polymer having a particularly uniform particle size, which is required for a gel for high performance GPC. Coalescing particles can be produced. In particular, when the aqueous phase is vibrated in the present invention, it is possible to produce polymer particles having a particle size of 1 to 30 μm and a coefficient of variation of 0.3 or less.

According to the present invention, it is possible to directly produce microporous polymer particles having a uniform particle size, which were conventionally difficult to produce. Therefore, it is possible to omit a classification operation for conventionally produced particles having a wide particle diameter distribution. As described above, since the classification operation can be omitted, in the present invention, the manufacturing operation is simplified as a whole, and the time required for the operation can be reduced. In addition, compared to the method of homogenizing the polymer particles produced by classification,
In the present invention, a high yield can be achieved because no waste is generated.

As described above, according to the present invention, for example, microporous polymer particles having a uniform particle diameter, which are in high demand as a gel for high performance GPC, can be easily produced at a high yield. Become. Moreover, according to the present invention, the scale can be increased as long as the mechanical strength of the inorganic film permits, and industrial polymer particles, that is, large-scale polymer particles can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus for producing a gel of the present invention used in Example 1.

FIG. 2 is a schematic view of an apparatus for producing a gel of the present invention used in Examples 2 to 7.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 SPG membrane 2 Jacket 3 Organic phase tank 4 Circulation pump 5 Water phase tank 6 Nitrogen cylinder 7 Pressure gauge 8 Vibromixer 9 Piston 10 Water phase tank 11 Pressure tank 12 Organic phase 13 Nitrogen cylinder 14 Pressure gauge 15 SPG film

Claims (3)

(57) [Claims] An organic phase comprising a polymerizable monomer, a cross-linkable monomer, a non-reactive organic solvent and a polymerization initiator is provided with pores having a uniform pore size in an aqueous phase containing a dispersant and a surfactant. By press-fitting through an inorganic membrane, a uniform O /
A method for producing porous polymer particles, comprising preparing a W-type emulsion and then performing polymerization. 2. The method for producing porous polymer particles according to claim 1, wherein a shirasu porous glass film is used as the inorganic film having pores having a uniform pore size. 3. The method for producing porous polymer particles according to claim 1, wherein an aqueous phase containing a dispersant and a surfactant is vibrated.