JPS61252202A - Production of uniform spherical polymer - Google Patents

Abstract

PURPOSE:To obtain the titled polymer having a uniform particle diameter and a high purity in good efficiency, by enveloping a specified amount of a monomer (solution) in a film to form a capsule, polymerizing the monomer (solution) in the capsule and removing the film therefrom. CONSTITUTION:A given amount of a monomer (solution) 5 comprising at least one functional group-containing monomer (e.g., styrene) and, optionally, a solvent (e.g., isooctane) and a polymerization initiator (e.g., benzoyl peroxide) is enveloped in a solution 6 (e.g., water) containing a film-forming agent (e.g., sodium alginate) immiscible with the monomer (solution) to form a concentric two-phase liquid drop 7 of a uniform diameter. A curing agent (e.g., CaCl2) is added to solution 6 to coagulate the film-forming agent into a film 8 and thereby form a capsule 9. This capsule 9 is heated to polymerize the monomer and obtain a polymer particle 10 enveloped in film 8. The film 8 is removed to obtain a spherical polymer comprising a polymer particle 10 and having a given particle diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a technology for producing spherical polymers, and particularly to a technology that is effective when applied to the production of spherical polymers with uniform particle size.

[Background technology]

Spherical polymers are of practical importance whether their internal structure is homogeneous or porous. For example, porous polymers are used as base materials for ion exchange resins, column packings such as gels for chromatography, and as carriers for catalysts or adsorbents. These are usually formed from a porous polymer having a two-dimensional network structure obtained by copolymerizing a monofunctional monomer and a desired amount of a polyfunctional monomer. It is said that it is extremely important for these spherical porous polymers to have uniform particle sizes in order to utilize them.

Methods for producing spherical polymers generally include a suspension polymerization method in which monomers are dispersed in water and polymerized, and an emulsion polymerization method in which an emulsifier is used in combination with the polymerization method.

However, with the above two methods, it is very difficult to control the spherical polymer to the desired uniform particle size, and sieving is required to obtain the spherical polymer with a constant particle size. The yield of spherical polymers must be low.

In addition, in the former case, droplets dispersed in a liquid tend to stick to each other, so it is necessary to take measures to prevent adhesion using an anti-aggregation agent. However, complete prevention of adhesion is extremely difficult.

Furthermore, regarding the latter, the influence of the emulsifier and the treatment of the emulsifier are problematic.

That is, it is impossible to uniformly and efficiently produce a spherical polymer with a desired particle size using conventional methods, and there is a strong demand for the development of a method for producing a spherical polymer with a desired uniform particle size.

[Purpose of the invention]

An object of the present invention is to provide a technique that can efficiently produce a highly pure spherical polymer having a desired uniform particle size.

[Summary of the Invention] The inventor of the present invention has accomplished the above-mentioned object (through repeated research).

That is, a certain amount of a mixed solution of one or more monomers or a solvent containing one or more monomers and a solvent, including a polymerization initiator if necessary, is covered with a film made of a material that is insoluble in the monomers or the mixed solution to form a capsule. The capsule is then treated under predetermined conditions to polymerize the monomer encapsulated within the film, and then the film of the capsule material is removed to produce a highly pure spherical polymer with uniform particle size. It can be easily manufactured and the above object can be achieved.

One feature of the present invention is that a uniform spherical polymer is produced by encapsulating a certain amount of the monomer or its solution.

As an effective method for forming this capsule, for example, Japanese Patent Application Laid-Open No. 57-19032 or Japanese Patent Application Laid-Open No. 59-1185
This method is explained in detail in Japanese Patent No. 9, and it is considered to be advantageous to carry out the process according to this method because of high production efficiency.

Next, an outline of the above method will be explained. In other words, Japanese Patent Publication No. 5
According to the technique disclosed in Japanese Patent No. 7-19032, from the inner nozzle of the concentric double nozzle, a mixed solution of two or more monomers or the monomers and a solvent containing a polymerization initiator if necessary ( (hereinafter also referred to as monomer solution)
A solution containing the monomer or a film-forming material that is not dissolved in the monomer solution is caused to flow out from the circumcenter nozzle while applying vibration to the concentric double nozzle to generate uniform concentric two-phase droplets. Next, the concentric two-phase droplets are encapsulated by falling through a mist layer made up of micro droplets containing a hardening agent for the film forming material using the technique disclosed in JP-A-59-11859. be.

The encapsulation method allows polymerization of monomers or monomer solutions containing a polymerization initiator while encapsulating them in capsules with a desired fixed volume, and therefore not only does not cause adhesion during polymerization. After polymerization, a spherical polymer having a uniform particle size can be obtained. Therefore, according to the present invention, there is no need for conventional anti-adhesive agents or emulsifiers, and there is no need for the labor-intensive operation of classification.

The present invention can utilize various monomers having one or more types of functional groups, and may also be a mixture of these monomers. Specifically, there are polyfunctional vinyl compounds such as monovinyl compounds and divinyl compounds.

Examples of monovinyl compounds include styrene compounds and acrylic compounds, examples of divinyl compounds include divinylbenzene derivatives, and examples of trivinyl compounds include trimethacrylic acid esters.

The above-mentioned mixed solution of monomer and solvent is prepared by dissolving the above-mentioned one or more monomers together with a polymerization initiator, if necessary, in a solvent.

As the polymerization initiator, for example, benzoyl peroxide, azoisobutyronitrile or t-butylhydroxyperoxide can be used. Further, the solvent is a lipophilic one that has high solubility for the monomer, and for example, an aliphatic solvent such as isooctane or pebtan, or an aromatic solvent such as toluene can be used.

As the coating liquid for forming concentric two-phase droplets enclosing the monomer mixture etc., an aqueous solution containing a film forming agent that does not mix with the monomer mixture etc. can be used. Examples of the film forming agent include sodium alginate and carboxymethyl cellulose.

Hardening agents for coagulating the film-forming agent include calcium chloride, sodium sulfate, etc., and an appropriate one can be selected depending on the type of film-forming agent and used as an aqueous solution.

As a treatment agent for removing the capsule film after polymerization, an aqueous solution of sodium polyacrylate or the like can be used.

A specific manufacturing process that is an example of the present invention will be described in more detail.

Figure 1 is a process diagram showing an outline of the manufacturing process;
The figure is a cross-sectional view showing the state of particles in each step shown in FIG. 1.

Step 1 is a step of forming droplets containing a predetermined amount of a monomer or a mixed solution of a monomer and a solvent, and step 2 is a step of forming a film on the surface of the predetermined amount of monomer, etc. The capsule forming step is a step of forming a droplet containing a predetermined amount of a monomer or a mixed solution of a monomer and a solvent. It consists of processes. In this capsule forming step, in Step 1, the above-mentioned monomer or two or more monomers or the monomer solution 5 as shown in FIG. After forming concentric two-phase droplets 7 with a particle size of
In step 2, capsules 9 can be formed by coagulating the film-forming agent in the outer liquid phase to form a film 8, as shown in FIG.

The two-phase droplet 7 is, for example,
It can be formed by the method detailed in Publication No. 2, and the diameter of each liquid phase of the two-phase droplet 7 to be formed is the diameter of the concentric double nozzle,
The optimum conditions are determined by the flow rate of each method, the frequency of vibration applied to the concentric double nozzle, and the physical properties of each method, and are determined by experiment. The vibration frequency ranges from 200 to several Klb, and the flow rate for each method is approximately 0.5 to 5+wl/sec. The subsequent film formation was also described in the above-mentioned Japanese Patent Application Laid-Open No. 59-1185.
Complete encapsulation is possible by following the method described in Publication No. 9.

Step 3 is a polymerization step, in which the monomer or monomer solution is heated in a hot water bath for an appropriate time while stirring in a hot water bath at about 80°C to 90°C, and the encapsulated monomer is polymerized to form a film 8. This results in polymer particles 10 covered with.

Step 4 is a film removal step, in which the film 8 can be removed by stirring the capsules after polymerization in a treatment tank containing an appropriate treatment agent 1, and the desired particle size made of the polymer particles 10 can be removed. A spherical polymer is produced.

〔Effect of the invention〕

According to the present invention, by enclosing a certain amount of a monomer or a monomer solution into a capsule, polymerization can be carried out within the capsule, and by subsequently removing the capsule film, spherical particles with a uniform diameter can be formed. The polymer can be easily produced.

In addition, this method does not require the use of additives as in conventional emulsion polymerization or suspension polymerization methods, so it is possible to produce spherical polymers with uniform particle size and high purity at a high yield. It is possible.

Furthermore, by encapsulating a monomer solution containing a polyfunctional monomer, porous spherical polymers with uniform particle size can be similarly produced.

As described above, the present invention relates to an industrially extremely useful technology.

Next, embodiments according to the present invention will be described.

(Example 1) A nozzle with an inner diameter of 1.2 fi and an outer diameter of 1.8 wna was
．． A 0.8% by weight aqueous solution of sodium alginate was placed on the outside of a double nozzle placed concentrically inside the 9H nozzle, and 36% by volume of Stereph, 24% by volume of divinylbenzene, and 39.4% by volume of isooctane were placed in the inside nozzle. % and benzoyl peroxide 0.6 volume % monomer mixed solution at 42 ml/win and 106 ml/win, respectively.
supply at a rate of Then, while supplying this monomer mixed solution, the double nozzle was heated at a vibration width of 100 μm and a vibration frequency of 40 μm.
0Hz"i: Vibrate to generate 400 concentric two-phase droplets with an outer diameter of 4.0 mm and a uniform particle size per second. Separately, an ultrasonic mist generator is used to generate calcium chloride at a temperature of 30 Hz.
A fine mist is generated from a wt % aqueous solution, suspended in an extremely weak air flow, and the concentric two-phase droplets fall from the center of the mist layer. While passing through this mist layer, a reaction between sodium alginate and calcium chloride occurs on the surface of the droplet to form water-insoluble calcium alginate, forming a film. The capsule particles are dropped into the calcium chloride aqueous solution to complete the encapsulation.Next, the capsule particles are slowly stirred in a 90°C hot water bath while the polymer particles coated with calcium alginate are poured into the calcium chloride aqueous solution. get. Then, sodium polyphosphate 1
The particles were transferred into a 0% by weight aqueous solution and chemically treated to remove the calcium alginate film to obtain uniform polymer particles with a diameter of 2.3 cm.

Incidentally, by finally removing the isooctane solvent, a porous spherical polymer having a uniform particle size can be obtained.

[Example 2] An experiment was conducted using heptane instead of isooctane as the diluent for the monomer mixture in Example 1, and uniform polymer particles with a diameter of 2.3 pieces were obtained in the same manner as in Example 1.

[Example 3] A monomer mixture and a film were applied in the same manner as in Example 1 to a double nozzle in which a nozzle with an inner diameter of 0.5 m and an outer diameter of 0.6 m was arranged concentrically inside a nozzle with an inner diameter of 0.9 mm. 16.7 ml/sin and 15.211/s of the solution containing the forming agent, respectively.
Uniform particles with a diameter of 1.1 (1M) were obtained by supplying the particles at a rate of 1.5 in. and vibrating at a frequency of 400 Hz.

Although the present invention has been described in detail above, it goes without saying that the present invention is not limited to the above embodiments.

For example, encapsulation of monomers or monomer solutions
JP-A-57-19032 and JP-A-59-1185
The method described in Publication No. 9 was explained, but 1. The present invention is not limited to this, and any method that can form a similar capsule may be used.

In addition, although we have only described an example in which a solution of two types of vinyl monomers, monofunctional and difunctional, styrene and divinylbenzene, mixed with a solvent is encapsulated, a solvent-free system may also be used, and the monomers used may be encapsulated. It may be one type or a mixture of three or more types.

Furthermore, it goes without saying that the type and method of polymerization are not limited to those shown in the Examples.

[Brief explanation of drawings]

FIG. 1 shows the steps of a method for producing a uniform spherical polymer according to an embodiment of the present invention, and FIG. 2 is a sectional view showing the state of particles in each step in FIG. ... Droplet formation step, 2. Film forming step, 3. Polymerization step, 4. Film removal step, 5. Monomer solution, 6. Solution containing film forming agent, 7. ... Concentric two-phase droplet, 8... Film, 9... Capsule, 10... Polymer particle.

Claims (3)

[Claims] (1) Consists of a step of covering a certain amount of a monomer or a mixed solution of a monomer and a solvent with a film to form a capsule, a step of polymerizing the monomer encapsulated in the film, and a step of removing the film. A method for producing a uniform spherical polymer. (2) The step of forming a capsule includes a step of forming a uniform concentric multiphase droplet enclosing a certain amount of a monomer or a mixed solution of a monomer and a solvent, and a step of forming a film on the outer phase of the droplet to form a capsule. A method for producing a uniform spherical polymer according to claim 1, comprising the step of encapsulating. (3) The method for producing a uniform spherical polymer according to claim 2, wherein the multiphase droplets are two-phase droplets.