JPH06107709A - Production of porous polymer particle - Google Patents

Abstract

PURPOSE:To provide a method for producing fine porous polymer particles having an uniform particle diameter, facilitating its industrial application in high yield. CONSTITUTION:The method for producing porous polymer particles comprises pressuring an organic phase comprising a polymerizable monomer, a crosslinkable monomer, a non-reactive organic solvent and a polymerization initiator into an aqueous phase containing a dispersing agent and a surfactant through an inorganic membrane having pores of uniform diameter and subsequently polymerizing the prepared uniform O/W type emulsion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 size. The microporous polymer particles having a uniform particle diameter of the present invention are particularly suitable as packing materials for liquid chromatography suitable for high-speed 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 packed with a porous packing material (hereinafter referred to as a gel), and a solution containing samples of various molecular sizes is passed through the column to sequentially separate samples of large molecular size from the column. It is a type of liquid chromatography for elution.

Conventionally, organic solvent-based GPC has been used in petrochemical,
Widely used in the field of polymer chemistry. Styrene-divinylbenzene-based copolymer particles, which have many characteristics, are widely used in this organic solvent-based GPC.

[0004]

In recent years, development of high-performance GPC gels has been strongly required as high-speed analysis progresses. For that purpose, high mechanical strength and uniform pores are provided. In addition, spherical and uniform fine particles are required.

Until now, various studies have been attempted on a method for producing microporous polymer particles having a uniform particle size. As a method for producing polymer particles, a suspension polymerization method is known in which a polymerizable monomer in an aqueous solvent, particles formed by dispersing a crosslinkable monomer and the like are taken out from the system, but in this method. Even if the optimum stirring conditions were determined, the distribution of oil droplets at the initial stage of polymerization could not be narrowed, and non-uniformity would progress due to repeated coalescence and division. was difficult.

As a method for solving this, a production method using a suspension stabilizer or a suspension stabilizing aid (Japanese Patent Laid-Open No. 52-1454).
89), a method of carrying out aqueous suspension polymerization under high-speed shearing stirring (Japanese Patent Publication No. 62-44561), and a method of carrying out suspension polymerization while irradiating a monomer with ultrasonic waves (JP-A-59-2193).
No. 03) has been proposed, but there are problems to be solved such as long process and low yield.

Seed polymerization method (JP-A-61-225208)
In contrast to the suspension polymerization method, the seed particles absorb and swell the monomer to enlarge the particles, so that uniform particles can be obtained. . However, this method has a problem that the manufacturing process is complicated and takes a long time, and the pore distribution, porosity and mechanical strength are not sufficient.

[0008]

Means for Solving the Problems The inventors of the present invention have made earnest studies on a method of microporous polymer particles having a uniform particle diameter, which is easy to industrially apply and can be carried out in a high yield. It was found that coalescence or fragmentation of the organic phase can be prevented by press-fitting it through an inorganic film having pores of uniform pore size, and the present invention has been completed.

That is, according to the present invention, an organic phase composed of a polymerizable monomer, a crosslinkable monomer, a non-reactive organic solvent and a polymerization initiator is added to an aqueous phase containing a dispersant and a surfactant so as to have a uniform pore size. A method for producing porous polymer particles, characterized in that a uniform O / W type emulsion is prepared by press-fitting through an inorganic film having pores, and then polymerization is carried out. Hereinafter, the present invention will be described in detail. The coefficient of variation V used in the present specification is represented by V = σ / x (where σ is a standard deviation (μm) and x is an arithmetic mean (μm). ) Is shown).

Examples of the polymerizable monomer include styrene derivatives such as styrene, ethylvinylbenzene, α-methylstyrene and chloromethylstyrene, methacrylic acid esters such as methyl methacrylate and ethyl methacrylate, methyl acrylate and ethyl acrylate. Acrylic esters such as, vinyl esters such as vinyl acetate, and suspension-polymerizable ones such as acrylonitrile, which may be used alone or in combination of two or more. Particularly, styrene and ethylvinylbenzene are preferable polymerizable monomers in the present invention in terms of physical properties of pores and the like.

Examples of the crosslinkable monomer include divinylbenzene (DVB), divinyltoluene, ethylene glycol diacrylate or dimethacrylate, polyethylene glycol diacrylate or dimethacrylate, and the like. You may use it in combination of 1 type or 2 types or more. In the present invention, especially 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 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 preferable. The amount of these solvents used may be in the range of 50 to 300% by volume based on the total amount of the 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 with respect to all monomers.
It may be used within the range of weight%, but there is no particular problem even if it exceeds the range.

As the dispersant, tricalcium phosphate (TCP), poorly soluble phosphate such as hydroxyapatite, polyvinyl alcohol (PVA), water-soluble polymer such as carboxymethyl cellulose, polyacrylamide, etc. One or two or more of them may be used, but PVA is particularly preferable in order to efficiently produce fine and uniform porous polymer particles. When these dispersants are used in a large amount, it tends to cause non-uniformity or agglomeration of the particles produced, leading to a decrease in yield, and conversely, when used in a small amount, it tends to cause non-uniformity of the particles produced. From the water phase to 0.
It is preferably used 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), nonionic surfactants and amphoteric surfactants. Anionic surfactants are preferred in order to efficiently produce fine and uniform porous polymer particles. Among them, SDS
Is particularly preferable. The surfactant is below the critical micelle concentration (CMC) peculiar to the one to be used and at a concentration in the aqueous phase of 0.01 to 1.0, preferably 0.1 to 0.5.
It is preferably used in the range of wt%.

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

Regarding the pressure and the like when the organic phase is pressed into the aqueous phase through the inorganic membrane to prepare an O / W type emulsion, the organic phase has a desired diameter and is dispersed to form an inorganic membrane. There is no limitation as long as it does not deform or break. For example, the pressure is 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.

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

In the present invention, when the porous polymer particles having a uniform particle size are produced more reliably, particularly when the organic phase is pressed into the aqueous phase through the inorganic film,
It is advisable to stir the aqueous phase so that the oil droplets of these organic phases do not coalesce or split. The stirring conditions are, for example, 100 to 300 rpm, more preferably 13 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. Although there is no particular limitation on the method of vibrating itself, for example, a method of irradiating ultrasonic waves or a vibrating membrane emulsifying device such as a commercially available mixer (for example, Vibro mixer, manufactured by Refrigeration Industry Co., Ltd.) 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
Is the range.

[0020]

EXAMPLES Examples will be described below to explain the present invention in more detail, but the present invention is not limited to these examples. Further, the average particle size and particle size distribution of the gel in the present invention are measured by collecting the gel on a preparation and dispersing it in a 5% PVA aqueous solution, and using an optical microscope (BHT-MD manufactured by Olympus Optical Co., Ltd.). After the photograph was taken, it was performed using a digitizer (made by Graphtec Co., Ltd.).

Example 1 The present invention was carried out using the apparatus shown in FIG. 1.50 wt% TCP and 0.05 wt% DBSNa in distilled water
In addition, it was dissolved and mixed to obtain an aqueous phase. Further, isooctane is 2.02 mol / L, styrene is 2.90 mol / L,
DVB is 2.38 mol / L, ADVN is 0.20mo
The mixture was mixed at a ratio of 1 / L to obtain an organic phase. In the apparatus of FIG. 1, this aqueous phase was put in an aqueous phase tank (5), circulated by a circulation pump (4), and fixed as a jacket (2) as an inorganic membrane (1) having a pore diameter of 1.10 μm. SPG
Using a membrane (manufactured by Asahi Glass Co., Ltd.), the organic phase is put in the membrane and in the organic phase tank (3), and the pressure gauge (7) is put through the SPG membrane using the nitrogen gas in the nitrogen cylinder (6). ) Is pressed for 1 hour so that the pressure becomes 0.6 to 0.8 kgf / cm2, and desorbed and dispersed in the water phase from the pores of the SPG membrane to make O / W.
A type emulsion was prepared.

Emulsion thus prepared is
It was transferred to a polymerization reactor set to 0 ° C., replaced with nitrogen gas, and then 132 rp using two blades made of stainless steel.
The mixture was stirred at m and polymerized for 8 hours. The obtained polymer particles were separated by filtration, washed with distilled water and ethyl alcohol in this order, and dried. The average particle size of the polymer particles was 9.56 μm, and the variation coefficient was 0.37.

Example 2 The present invention was carried out using the apparatus shown in FIG. 1.00 wt% PVA and 0.10 wt% DBSNa in distilled water
In addition, it was dissolved and mixed to obtain an aqueous phase. Further, isooctane is 2.02 mol / L, styrene is 2.90 mol / L,
DVB is 2.38 mol / L, ADVN is 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 added to the organic phase tank (5) in the pressure tank (4).
And SP with a pore size of 1.10 μm similar to that of Example 1
The G membrane (8) was installed in the water phase tank (3), and the pressure of the pressure gauge (7) was 0.4 kgf / cm @ 2 through the membrane using the nitrogen gas in the nitrogen cylinder (6). And press-fit for 1 hour so that the vibromixer-
An O / W type emulsion was prepared by desorbing and dispersing in a water phase which was vibrated by the reciprocating motion of the piston (2) whose rotation speed was 662 rpm.

Emulsion thus prepared is
It was transferred to a polymerization reactor set to 0 ° C., and after purging with nitrogen gas, it was heated to 220 r using two blades made of stainless steel.
It was polymerized at pm for 6 hours. The obtained polymer particles were separated by filtration, washed with distilled water and ethyl alcohol in this order, and dried. The average particle size of the polymer particles was 6.61 μm, and the variation coefficient was 0.27.

Example 3 The same operation as in Example 2 was carried out except that SDS was used as the surfactant in the aqueous phase. The average particle size of the obtained polymer particles was 6.48 μm, which varied. 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 0.20% by weight.
The obtained polymer particles had an average particle diameter of 6.36 μm and a coefficient of variation of 0.18.

Example 5 The same operation as in Example 2 was carried out except that the pore size of the SPG film was changed to 0.52 μm. The average particle size of the obtained polymer particles was 4.22 μm, which varied. The coefficient is 0.18
Met.

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

Example 7 The same operation as in Example 2 was carried out except that the pore size of the SPG film was changed to 5.50 μm. The average particle size of the obtained polymer particles was 17.38 μm, which varied. Coefficient is 0.3
It was 0.

[0030]

As is apparent from the above description, according to the production method of the present invention, the organic phase is interfused with the dispersant through the (preferably porous) inorganic film having pores of uniform pore size. An O / W emulsion is prepared by press-fitting 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 high-performance GPC gel. Coalescent particles can be produced. In particular, when the aqueous phase is vibrated in the present invention, it is also 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 diameter, which has been difficult to produce conventionally. Therefore, it is possible to omit the classification operation for the conventionally produced particles having a wide particle size distribution. Since the classification work can be omitted in this way, the manufacturing operation is simple and the time required for the operation can be shortened in the present invention as a whole. Further, in comparison with the method for achieving homogenization of polymer particles produced by classification,
It is also possible to achieve high yields since nothing is thrown away in the present invention.

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 in a high yield. Become. Moreover, the present invention can be scaled up to the extent that the mechanical strength of the inorganic film allows, and industrial polymer particles, that is, large-scale polymer particles, can be easily manufactured.

[Brief description of drawings]

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

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

[Explanation 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)

[Claims] 1. An organic phase comprising a polymerizable monomer, a crosslinkable monomer, a non-reactive organic solvent and a polymerization initiator, and an aqueous phase containing a dispersant and a surfactant having pores of uniform pore size. By press-fitting through an inorganic film, uniform O /
A method for producing porous polymer particles, which comprises 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 membrane is used as the inorganic membrane having pores of uniform pore size. 3. The method for producing porous polymer particles according to claim 1, wherein the aqueous phase containing the dispersant and the surfactant is vibrated.