JPH0959305A - Method for producing acrylic polymer particles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an acrylonitrile polymer particle having a high strength against compression fracture of resin caused by the pressure of liquid flow and useful as the base of an absorbent, etc., by polymerizing an acrylonitrile monofunctional monomer with a polyfunctional monomer having plural double bonds in a molecule in an aqueous medium under specific conditions. SOLUTION: This acrylonitrile polymer particle is obtained by the suspension polymerization of an acrylic monofunctional monomer such as a (meth)acrylic acid ester or a (meth)acrylonitrile with a polyfunctional monomer such as divinylbenzene having two or more than two double bonds in a molecule at a concentration preferably of 2-20wt.% based on the total monomer in an aqueous medium using a radical initiator such as azobisisobutyronitrile in the presence of oxygen at 0.15-1 millimol/1 mol of monomer in the polymerization system.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing crosslinked polymer particles used as a base for an ion exchange resin, a chelate resin, a separating agent for chromatography, and an adsorbent.

[0002]

2. Description of the Related Art By subjecting an acrylic monofunctional monomer such as an acrylic ester or acrylonitrile and a polyfunctional monomer such as divinylbenzene to suspension polymerization in an aqueous medium in the presence of a radical polymerization initiator or the like. Methods for obtaining crosslinked polymer particles are widely known. Further, as a method for producing the crosslinked polymer particles used as a base resin for an ion exchange resin or a chelate resin, Japanese Patent Publication No. 50529/1993 discloses:
There has been proposed a method for producing an acrylonitrile polymer using alkyl cellulose and polyoxyethylene polyoxypolyprene block polymer or gelatin as a suspension stabilizer.

[0003]

Generally, a functional group is added to a crosslinked polymer particle to form an ion exchange resin or a chelate resin, and when the resin is filled in a column and a treatment liquid is flown, pressure is applied to the resin. In addition, the treatment liquid and the liquid for regeneration are acidic,
It is alkaline, and so-called osmotic shock in which the resin swells and contracts occurs when these are repeatedly contacted. When the resin is used in this manner, the crushing of the resin due to the applied pressure and the crushing of the resin due to the osmotic shock progress.

Therefore, when used as an ion-exchange resin or a chelate resin, a method for producing a base resin having high strength against compression crushing of the resin due to pressure when passing the treatment liquid and destruction due to osmotic shock is provided. To do.

[0005]

The present invention is a suspension of an acrylic monofunctional monomer and a polyfunctional monomer having two or more double bonds in the molecule in an aqueous medium using a radical initiator. In the method for producing acrylic polymer particles, the polymerization is carried out in the presence of 0.15 to 1 mmol of oxygen / 1 mol of the monomer in the polymerization system.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The acrylic monofunctional monomer of the present invention is at least one selected from (meth) acrylic acid esters and (meth) acrylonitrile. Examples of (meth) acrylic acid esters include acrylic acid esters such as methyl acrylate, ethyl acrylate and butyl acrylate; and methacrylic acid esters such as methyl methacrylate, ethyl methacrylate and butyl methacrylate. Examples of the (meth) acrylonitrile include acrylonitrile and methacrylonitrile. These may be selected because they easily give the functional groups of the ion-exchange resin or chelate resin used for the obtained polymer particles.

The polyfunctional monomer having two or more double bonds in the molecule of the present invention includes divinylbenzene, divinyltoluene, divinylxylene, trivinylbenzene,
Aromatic polyfunctional monomers such as trivinylxylene; ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, decaethylene glycol di (meth) acrylate, etc. ) Ethylene glycol di (meth) acrylate; (poly) propylene such as propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, decapropylene glycol di (meth) acrylate, etc. Glycol di (meth) acrylate; (meth) acrylic acid esters of polyhydric alcohols such as pentaerstol tetra (meth) acrylate; unsaturated alkyl (meth) acrylates such as allyl (meth) acrylate. ) Acrylic acid esters and the like can be mentioned. Of these, divinylbenzene is preferable from the viewpoint of the chemical and physical strength of the polymer particles obtained.

In the present invention, the polyfunctional monomer having two or more double bonds in the molecule is 2 to 20% by weight based on the total monomers.
It is. If the amount of the polyfunctional monomer having two or more double bonds in the molecule is less than 2% by weight, the mechanical strength of the obtained polymer particles will be low, and if it exceeds 20% by weight, the obtained polymer particles will be deteriorated. When used as an ion exchange resin or a chelate resin, their adsorption performance is reduced.

In the present invention, the aqueous medium is mainly water containing a suspension stabilizer and the like. The ratio W / O of the aqueous medium to the total monomers is 1-10. If the amount is too small, the particle shape is deteriorated and a large amount of polymer meal is produced.
On the other hand, if the amount is too large, the amount of fine particles produced increases and the particle size distribution becomes wider.

Well-known suspension stabilizers are used as the suspension stabilizer of the present invention. For example, alkyl cellulose, hydroxyalkyl cellulose, hydroxyalkyl alkyl cellulose, polyoxyethylene polyoxypolyprene block polymer, gelatin or the like. You may use 2 or more types together. The amount of suspension stabilizer used is
The amount is 0.0005 to 5 parts by weight based on 100 parts by weight of all the monomers.

The radical initiator of the present invention may be a well-known oil-soluble one used for the polymerization of vinyl monomers. Specific examples of such an oil-soluble radical initiator include azo compounds such as azobisisobutyronitrile and azobisisovaleronitrile, and diisopropyl peroxydicarbonate, lauroyl peroxide, benzoyl peroxide, t-butyl peroxide. Examples thereof include organic peroxides such as oxybenzoate and t-butyl peroxide. These can be used as a mixture of two or more kinds.
The amount of the initiator used is 0.0 with respect to the total amount of the charged monomers.
The ratio is about 001 to 0.03 times.

In the present invention, the total amount of the monomer 1 in the polymerization system is 1
Polymerization is carried out in the presence of 0.15 to 1 mmol of oxygen per mol. The amount of oxygen in the polymerization system is the total amount of the gas phase portion and the liquid phase portion. Since the oxygen amount is consumed as the polymerization progresses, the oxygen amount in the polymerization system decreases, but a predetermined amount may be present in the polymerization system until 30% of all monomers are polymerized. If the amount is less than 0.15 mmol based on 1 mol of all the monomers, the osmotic shock strength of the resulting polymer particles is insufficient. When it exceeds 1 millimole, the polymerization rate becomes slower and more fine particles and agglomerated particles are generated.

In order to allow a predetermined amount of oxygen to exist in the polymerization system, a method of adjusting the degree of substitution of the inside of the polymerization system with an inert gas, a method in which oxygen is once expelled with an inert gas, and then air or oxygen is used. There are a method of feeding a gas and a method of using water in which oxygen is dissolved in an aqueous medium.
More specifically, the water phase in the gas phase and the liquid phase before the initiation of polymerization, the oxygen concentration of the monomer phase is measured and calculated, by a method that is easy to supply the shortfall from the gas phase. is there.

In the present invention, the resulting acrylic polymer particles can be made porous. For example,
There is a method of adding an organic solvent that is soluble in the monomer but insoluble in the polymer. By making the polymer particles porous, the ion exchange resin and chelate resin obtained from the polymer particles have a characteristic of increasing the metal adsorption rate. Specifically, as the organic solvent, hydrocarbon compounds such as butane, hexane, heptane and dodecane; alcohols such as amyl alcohol, hexanol and dodecanol; aromatic compounds such as benzene, toluene, xylene and ethyltoluene; Examples thereof include ketones such as methyl ethyl ketone and methyl butyl ketone. The amount of the organic solvent used is 0.1 to 1.5 times the total amount of the monomers.

The suspension polymerization reaction may be a well-known method. For example, as the stirring strength increases, the particle size tends to decrease, and when the stirring strength decreases, the particle size tends to increase. Therefore, it may be determined by conducting a suitable preliminary experiment. The polymerization temperature is
The temperature may be set to a temperature corresponding to the decomposition temperature of the polymerization catalyst, but generally a range of about 30 to 120 ° C is preferable.

When an organic solvent is used after completion of the polymerization, the organic solvent is removed by subjecting it to an operation such as distillation, and the organic solvent is washed or dried as it is, and then used for ion exchange resin, chelate resin or chromatography. It can be used as a raw material for a separating agent, an adsorbent or the like.

[0017]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. The evaluation and measurement methods in the examples are as follows.・ Oxygen measuring method: The gas phase oxygen concentration is 3 mmφ using gas chromatography (GC-14B manufactured by Shimadzu Corporation).
* 5m column was packed with packing material Shimadzu's molecular sieve-5A 60-80 mesh, and TC was used as a detector.
Measured using D and Ar as carrier gas.
The amount of oxygen in the water phase was measured by a dissolved oxygen meter (DO-11 manufactured by Toa Denpa Co., Ltd.).
Measured using P). Oxygen in the organic phase was measured using a dissolved oxygen meter (UC-12 type manufactured by Central Science Co., Ltd.). -Giving functional groups to polymer particles: 100 g of acrylic polymer particles were stirred and permeated in 600 ml of 25% aqueous sodium hydroxide solution at a temperature of 90 ° C for 6 hours, and then washed with water. -Compressive strength: The polymer particles having a functional group are wet-sorted with a JIS standard sieve of 20 to 30 mesh,
The polymer particles were held in water, taken out from the water for each measurement, and the compressive strength was measured by a compressive strength measuring device (Token Co., Ltd., model caloric type 300).・ Osmotic shock strength: 70 ml of polymer particles with functional groups were measured with a graduated cylinder, and the inner diameter was 1
One cycle is packed in a column of 0 mm and length of 1 m, and 3N-sulfuric acid, deionized exchanged water, 2N-sodium hydroxide and deionized exchanged water are passed through the column for 7 minutes at a flow rate SV = 40 / hour, respectively. As a result, 50 cycles were passed. afterwards,
Normal particles and cracked particles were counted and expressed by% under a microscope.

EXAMPLE 1 500 g of deionized water was added to 1.2 L of an autoclave apparatus.
% Methylcellulose aqueous solution 0.93 g, 5% polyoxyethylene-polyoxypropylene condensate aqueous solution 7.49
and 480 ml (25 ° C.) of an aqueous phase consisting of 13.7 g of anhydrous sodium sulfate. Nitrogen gas was fed into the autoclave, pressurized to 2 kg / cm ² G, and purged twice. The gas phase oxygen concentration is 1.8.
% By volume. Water phase oxygen concentration is 0.9 mg / L as a result
Met. Acrylonitrile, divinylbenzene (purity 55%), and toluene used were those in which dissolved oxygen was destroyed by nitrogen gas to below the measurement limit. Acrylonitrile 1
09 g, divinylbenzene 19.8 g and toluene 7
0.985 g of lauroyl peroxide was dissolved in 9 g and charged. The amount of oxygen was 0.18 mmol per mol of all the monomers. The mixture was stirred at 440 rpm. While continuing stirring, the temperature of this compound was raised and kept at 60 ° C for 4 hours, 70 ° C for 1 hour, and 85 ° C for 1 hour.
Polymerization was carried out for a time. After the completion of this polymerization, it was washed with water and dried. A functional group was added to the obtained polymer particles and evaluated.
Table 1 shows the evaluation results.

Example 2 The same procedure as in Example 1 was carried out except that the nitrogen charge was changed so that the gas phase oxygen concentration was 4.0% by volume and the water phase oxygen concentration was 1.9 mg / L. Oxygen amount is 0.4 per mol of all monomers
It was 0 mmol. Table 1 shows the evaluation results.

Example 3 The procedure of Example 1 was repeated, except that the amount of nitrogen charged was changed so that the gas phase oxygen concentration was 8.0% by volume and the water phase oxygen concentration was 2.5 mg / L. Oxygen amount is 0.7 per 1 mol of all monomers
It was 8 mmol. Table 1 shows the evaluation results.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the nitrogen charge was changed so that the gas phase oxygen concentration was 0.1% by volume or less and the water phase oxygen concentration was 0.1 mg / L. The amount of oxygen was 0.002 mmol based on 1 mol of all the monomers. Table 1 shows the evaluation results.

Example 4 Into 1.2 L of autoclave apparatus, 500 g of deionized water, 1
% Methylcellulose aqueous solution 1.56 g, 5% polyoxyethylene-polyoxypropylene condensate aqueous solution 6.21
and 480 ml of an aqueous phase consisting of 13.8 g of anhydrous sodium sulfate. Nitrogen gas was fed into the autoclave, pressurized to 2 kg / cm ² G, and purged twice. When the oxygen concentration in the polymerization tank was measured, it was 1.9% by volume. Water phase oxygen concentration is 0.9m
g / L. Acrylonitrile, divinylbenzene (purity 55%), and toluene used were those in which dissolved oxygen was destroyed by nitrogen gas to below the measurement limit. Acrylonitrile 99g, divinylbenzene 35g and toluene 7
0.895 g of lauroyl peroxide was dissolved in 2 g and charged. The amount of oxygen was 0.20 mmol based on 1 mol of all the monomers. The mixture was stirred at 440 rpm. While continuing stirring, the temperature of this compound was raised and kept at 57 ° C for 4 hours, at 70 ° C for 1 hour and further at 85 ° C for 1 hour.
Polymerization was carried out for a time. After the completion of this polymerization, it was washed with water and dried. A functional group was added to the obtained polymer particles and evaluated. Table 1 shows the evaluation results.

Example 5 The procedure of Example 4 was repeated, except that the nitrogen charge was changed to make the gas phase oxygen concentration 4.3% by volume and the water phase oxygen concentration 2.0 mg / L. Oxygen amount is 0.44 per mol of all monomers
It was millimole. Table 1 shows the evaluation results.

Example 6 The procedure of Example 4 was repeated, except that the nitrogen charge was changed to make the gas phase oxygen concentration 8.4% by volume and the water phase oxygen concentration 2.6 mg / L. Oxygen amount is 0.8 for 1 mol of all monomers
It was 6 mmol. Table 1 shows the evaluation results.

Comparative Example 2 Example 4 was repeated except that the nitrogen charge was changed to make the gas phase oxygen concentration 0.1 volume% or less and the water phase oxygen concentration 0.1 mg / L.
I went the same way. The amount of oxygen is 0.0 per mol of all monomers
It was 02 mmol. Table 1 shows the evaluation results.

[0026]

[Table 1]

[0027]

The ion exchange resin or chelate resin produced by using the polymer particles obtained according to the present invention as a base resin is superior to the conventional ion exchange resin or chelate resin in that The strength against compression crushing and the strength of osmotech are large, and it can be used under severe conditions for a long time, and its industrial value is extremely large.

Claims (2)

[Claims] 1. When an acrylic monofunctional monomer and a polyfunctional monomer having two or more double bonds in the molecule are subjected to suspension polymerization in an aqueous medium using a radical initiator, the polymerization is carried out within the polymerization system. A method for producing acrylic polymer particles, characterized in that oxygen is polymerized in the presence of 0.15 to 1 mmol / monomer 1 mol. 2. The polyfunctional monomer having two or more double bonds in the molecule is divinylbenzene, and the amount thereof is 2 to 20% by weight based on the total amount of the monomers [. The method for producing acrylic polymer particles according to claim 1.