JPS6349258A - Weakly basic anion-exchange resin and its production - Google Patents

Abstract

PURPOSE:To enhance the stability of the title anion-exchange resin by holding a specified amt. of a quaternary amino group based on a tertiary amino group on a haloalkylbenzene structural unit wherein a weakly basic anion-exchange group is introduced. CONSTITUTION:When a copolymer of a monovinyl aromatic monomer crosslinked by a polyvinyl monomer and having a haloalkyl group is aminated by a dialkylamine, 2-25% quaternary amino group based on the tertiary amino group is introduced into the haloalkylbenzene structural unit by the reaction of the tertiary amine to produce a physical stable weakly basic anion-exchange resin. Polyvinyl aromatic monomer, polyvinyl aliphatic monomer, etc., are exemplified as the polyvinyl monomer, and trimethylamine, etc., are exemplified as the tertiary amine.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a weakly basic anion exchange resin and a method for producing the same, and more specifically, it provides a physically stable weakly basic anion exchange resin. .

Conventional technology and its problems Conventionally, weakly basic anion exchange resins obtained by aminating a crosslinked copolymer of aromatic monomers having a haloalkyl group with a secondary amine such as dimethylamine have been produced by desalting, It is used in many ways, such as refining sugar solutions. However, these weakly basic anion exchange resins, which adsorb anionic components during fluid delivery and turn into salt form and then into free base form through regeneration treatment, repeatedly expand and contract with each cycle. It is well known that the physical strength gradually decreases due to fatigue of the host structure, eventually resulting in broken beads.

The degree of volume change accompanying swelling and contraction varies depending on the matrix structure of the ion exchange resin and the degree of crosslinking. It also varies depending on the type and concentration of anions in the aqueous solution being treated, but it is usually quite large. For example, to Diaion ■W-30 (which is a commercially available weakly basic anion exchange resin)
Mitsubishi Chemical ■, product name) and Amberlight ■IRA-
93 (trade name, Rohm and Haas), etc., it is known that the free base form swells by 20 to 30% due to the change from the free base form to the chloride ion form.

In the use of such weakly basic anion exchange resins,
It is desirable to reduce the difference in repeated swelling and contraction in order to obtain weakly basic anion exchange resins that are physically stable and have excellent durability. This is also desirable from the point of view of effective utilization of the capacity of the actual device column.

It is generally known that resins with a low degree of crosslinking have a large degree of swelling and contraction, and in order to obtain a resin with a small volume change, it is necessary to increase the degree of crosslinking. But in this case,
As the degree of crosslinking increases, the ion exchange capacity per introduced dry resin mass decreases, and the utilization efficiency of the introduced ion exchange groups also tends to decrease. The reality is that exchange resins are selected to have a degree of crosslinking that is judged to be practical, taking both of these aspects into consideration.Therefore, there is a need for a method of reducing swelling and shrinkage without increasing the degree of crosslinking.

Means to Solve the Problem When basic anion exchange resins are regenerated with alkali, weakly basic anion exchange resins become mostly free bases, whereas strongly basic anion exchange resins become water-based. Becomes oxide ion type. When the resin volume of this regenerated form becomes the chloride ion form, it swells in a weakly basic anion exchange resin.
Strongly basic anion exchange resins are known to undergo the opposite volume change of shrinkage.

The present inventors focused on the different volume change properties of this strongly basic anion exchange resin, and by replacing a part of the weakly basic anion exchange group with a strongly basic ion exchange group, The inventors have found ways to solve these problems and have arrived at the present invention.

That is, the first aspect of the present invention is a weakly basic anion having a dialkylamino group as a weakly basic anion exchange group, which is made of a copolymer of a monovinyl aromatic monomer crosslinked with a polyvinyl monomer and having a haloalkyl group. A physically stable weak exchange resin which retains 2 to 25% of quaternary amino groups based on tertiary amines relative to the haloalkylbenzene structural unit into which a weakly basic anion exchange group is introduced. It is a basic anion exchange resin.

According to a preferred embodiment of the second aspect of the present invention, a copolymer of a monovinyl aromatic monomer crosslinked with a polyvinyl monomer and having a haloalkyl group is reacted with a tertiary amine, and then with a dialkyl amine. This is a method for producing a weakly basic anion exchange resin, which comprises introducing 2 to 25% of quaternary amino groups based on tertiary amine to the haloalkylbenzene structural units in the copolymer.

The weakly basic anion exchange resin of the present invention has haloalkylbenzene structural units within a range that does not substantially sacrifice the woody function as a weakly basic anion exchange resin, that is, the weakly basic anion exchange property. It is characteristic in that the upper limit is 25% of the quaternary amino group based on the tertiary amine, and the lower limit is kept at 2%, which effectively shows the effects of the present invention.

The method for producing the weakly basic anion exchange resin of the present invention will be described in detail below.

The copolymer of a monovinyl aromatic monomer crosslinked with a polyvinyl monomer and having a haloalkyl group according to the present invention is produced by a known polymerization method.

That is, for example, a copolymer obtained by copolymerizing a monovinyl aromatic monomer and a polyvinyl aromatic monomer or a polyvinyl aliphatic monomer as a crosslinking agent is reacted with a haloalkylating agent in the presence of a free-solutafluorocatalyst. Manufactured by

Specific examples of monovinyl aromatic monomers used in the above production method include styrene, chlorostyrene, methylstyrene, ethylstyrene, etc., and examples of polyvinyl aromatic monomers include divinylbenzene, divinylnaphthalene,
Divinyltoluene, trivinylbenzene, etc. are commonly used as polyvinyl aliphatic monomers, ethylene glycol di(meth)acrylate, trimethylolpropane triacrylate, allyl di(meth)acrylate, etc. are commonly used as free sol fluorocarbon catalysts. A solution consisting of aluminum chloride, zinc chloride, iron chloride, etc., a haloalkylating agent such as chloromethyl methyl ether, chloroethyl ether, etc., a chlorinating agent such as hydrochloric acid, thionyl chloride, chlorosulfonic acid, etc., and methanol, formalin, etc. are mentioned.

It will be done.

On the other hand, chloromethylstyrene, bromomethylstyrene,
When using a monovinyl aromatic monomer having a haloalkyl group such as chloroethyl styrene, it is copolymerized with the above-mentioned polyvinyl aromatic monomer or polyvinyl aliphatic monomer to have a haloalkyl group crosslinked directly with the polyvinyl monomer. A copolymer of monovinyl aromatic monomer is produced.

In the present invention, it is also possible to copolymerize by adding aliphatic monomers such as acrylonitrile, acrylic acid alkyl esters, methacrylic acid alkyl esters, etc. to these seven polymers within a range that does not interfere with the performance of the weakly basic anion exchange group. It is.

In producing the copolymer, known polymerization methods such as emulsion polymerization, bulk polymerization, and suspension polymerization can be employed, but suspension polymerization is preferred. Also, during polymerization, the physical properties of the resulting copolymer are changed uniformly.
For example, it is preferable to coexist a pore-forming agent that imparts porosity. Such pore-forming agents include, for example, organic liquids (precipitants) that act as a solvent on the monomer mixture, are substantially insoluble or sparingly soluble in water, and do not swell the resulting copolymer; An organic liquid (swelling agent) that acts as a solvent, is substantially insoluble or sparingly soluble in water, and causes the resulting copolymer to swell, an organic liquid that coexists with the swelling agent and a precipitant, the swelling agent, and this organic liquid. An organic liquid consisting of a monovinyl linear polymer capable of forming a homogeneous liquid phase with a swelling agent, further soluble in a 1,000 ml mixture;
Examples include inert polymers such as polyalkylene gellicol, which are inert to the produced copolymer.
It is also possible to use other known pore-forming agents without being limited to these. The porous crosslinked copolymer thus obtained is usually 0.1 to 1. Occ/g (
(by mercury pressure porosimeter), preferably 0.3
It has a porosity of the order of ~0.8 cc/g, which is desired to obtain a weakly basic anion exchange resin with adequate strength and ion exchange capacity.

The weakly basic anion exchange resin of the present invention uses a copolymer of a monovinyl aromatic monomer having a haloalkyl group crosslinked with such a polyvinyl monomer, and a dialkylamine and a tertiary amine as an aminating agent. In the amination reaction, 2 to 25% of quaternary amino groups based on tertiary amines are introduced to the haloalkylbenzene structural units in the crosslinked polymer.

In the amination reaction of the present invention, a highly reactive tertiary amine can be reacted simultaneously with a dialkylamine, but the tertiary amine is reacted first during the amination step, and then the remaining haloalkyl It is also possible to react the group with a dialkylamine, and this method is particularly preferred in order to ensure that the desired amount of tertiary amine is reacted. For example, when trimethylamine or dimethylaminoethanol is used as a tertiary amine and dimethylamine is used as a secondary amine, trimethylamine etc. is highly reactive, and the desired amount of trimethylamine etc. is usually added by quantitatively reacting. A weakly basic anion exchange resin in which 2 to 25% of quaternary amine groups based on tertiary amines have been introduced to the haloalkylbenzene structural units in the crosslinked copolymer is produced through an amination reaction in which dimethylamine is added. can get.

The amination reaction using a tertiary amine in this method usually takes about 0.25 to 5 hours to complete the reaction.

The amination reaction is carried out using an ether solvent such as water or dioxane, an aromatic solvent such as chlorobenzene, benzene, toluene, xylene, or other alcoholic solvent at a temperature of 20 to 100°C for 2 to 20 hours. This can easily be done by letting people know.

Specific examples of dialkylamines used in the present invention include dimethylamine, diethylamine, dipropylamine, etc. - Examples of tertiary amines include trialkylamines such as trimethylamine and triethylamine;
Examples include amino alcohols such as triethanolamine, dimethylaminoethanol, jetanolmethylamine, and jetanolethylamine.

Function Generally, in the production of weakly basic anion exchange resins, copolymers of vinyl aromatic monomers having haloalkyl groups (
It is known that when 1) is aminated with a secondary amine such as dimethylamine, a strongly basic ion exchange group is generated by the following side reaction.

In other words, after dimethylamine reacts with a haloalkyl group to form a tertiary amine, the neighboring haloalkyl group reacts with this before reacting with dimethylamine, forming a strongly basic anion that forms a cross-linked structure via the nitrogen atom. It is said that a structure of ion exchange group (2) is generated.

This strong basic ion exchange group (2) is larger in the following two points than the strong basic ion exchange group (3) shown by the general formula below, which is usually produced from a tertiary amine such as trimethylamine. They have functional differences and are undesirable.

That is, the strongly basic ion exchange group (2) having a crosslinked structure is 2
However, in the structure of the strongly basic ion exchange group (3), one haloalkylbenzene group can be formed from one haloalkylbenzene group, so the total ion exchange capacity is as follows: Although the structure does not reduce it, (2)
The more structures included, the lower the value will be.

In addition, the structure (2) means that a new crosslinked structure is created in the resin matrix, which increases the degree of crosslinking and increases the probability that the ion exchange groups in the resin will be covered. The access of counterions is inhibited, resulting in a decrease in the utilization efficiency of ion exchange groups. Against the dough (3
The strongly basic ion exchange group with the structure of Improvement is expected.

The strongly basic ion exchange group (3) introduced into the weakly basic anion exchange resin using a tertiary amine is
The strong basic ion exchange group (2) produced as a side reaction of amination with a secondary amine has a very different effect on the function as an ion exchange resin.

Effects of the Invention The weakly basic anion exchange resin of the present invention has significantly improved physical strength during practical use. Therefore, weakly basic anion exchange resins can be used more stably for a longer period of time than conventional anion exchange resins in processing operations such as desalting, purification of sugar solutions, and separation and purification of substances.

Example The present invention will be further explained with reference to Examples.

Test method 1.) Measurement of the bead crushing rate by acid-alkali cycle test: The bead crushing rate was determined by the acid-alkali cycle test in which one cycle consisted of adsorption swelling treatment with a 10% acetic acid aqueous solution and regeneration treatment with a 4% caustic soda aqueous solution. It was investigated using the method.

(+) 120aj 5trl of free base resin with constant diameter
A wide-mouth bottle contains about 7 ounces of ionized water (8 ounces with LUJ).

(2) Remove the liquid with a siphon with a filter, then
Add 1/70% acetic acid to the resin.

(3) Shake the wide mouth bottle containing the resin for 15 minutes.

(4) Drain the acetic acid aqueous solution, add 70ffi1 of water and wash with water.

(5) Add 70 ml of 4% caustic soda aqueous solution and simmer for 15 minutes.

(6) Drain the 4% caustic soda aqueous solution, add 70 ml of water, and wash with water.

The above steps (1) to (6) are considered as one cycle.

To measure the crushing rate, after drying the resin after the cycle test, approximately 0.1% of finely ground magnesium oxide was added.
Mix evenly.

This was placed in the center of a resin shape measuring device with a diameter of 600 mm and a disk set at an inclination of 3.4 degrees, and the resin was rotated at a rate of 4 to 5 times per minute to collect the resin that fell from the disk and its weight was measured. Then, find the sphericity and calculate the crushing rate (100-
The sphericity ratio) was calculated.

2) Measurement of swelling ratio: The ratio of the resin volume in the alkali regenerated form to the resin volume in the chloride ion form was defined as the swelling ratio.

10 (1 ml of resin was placed in a 200 ml glass column, washed with deionized water, backwashed, left to stand, (]) I
After 12 flushes of N caustic soda, flush 0.5 flushes of deionized water. Next, the column was backwashed with deionized water and left to stand, and the height of the resin in the column was measured to determine the resin volume, which was taken as the resin volume (I) in the alkali regenerated form.

(2) 1 liter of IN hydrochloric acid was poured into the resin regenerated in (1), followed by 0.5 liters of deionized water. flowed.

Next, the column was backwashed with deionized water and left to stand, and the height of the resin in the column was measured to determine the resin volume, which was taken as the resin volume (If) in the form of chloride ions.

The swelling ratio was determined by the following formula.

Swelling rate (%) = (II) / (I) x to.

Example 1 Sample 1): 79.5 g of styrene-divinylbenzene copolymer (divinylbenzene content 5.2%) produced by suspension polymerization using methyl isobutyl carbinol as a pore-forming agent.
After adding 333 g of chloromethyl methyl ether to sufficiently swell the polymer, 76 g of anhydrous zinc chloride was added and reacted at 40° C. for 7 hours with stirring. After the reaction is complete,
Thoroughly wash with water, dry, and chloromethylated copolymer 110
I got g. The chlorine content of this chloromethylated copolymer is 2
0.2%, suspended in water, and added 7.16 g of trimethylamine hydrochloride (1% per chloromethyl group).
2% equivalent) was added and stirred. Then 50% caustic soda 1
80 g of the solution was added dropwise over 1 hour while keeping the liquid temperature below 25°C, and the mixture was further stirred at 25°C for 2 hours to react with trimethylamine. After completion of this reaction, almost no unreacted trimethylamine was detected in the reaction solution.

Thereafter, 157 ml of a 50% aqueous solution of dimethylamine was added dropwise at the same temperature over 30 minutes. The reaction mixture was heated for an additional 1 hour, 2
After stirring at 5°C, the mixture was heated to 40°C and stirred for 4 hours to complete the amination reaction.

After completion of the reaction, the produced resin was separated by filtration, washed with water, and then mixed with 12 IN aqueous hydrochloric acid solution - 0.1 IN aqueous demineralized water - 1 IN aqueous sodium hydroxide solution
4- Washed with 0.5 ft of demineralized water. This resin had a total anion exchange capacity of 4.84 meq/g, a strong basic ion exchange capacity of 0.79 meq/g, a water content of 54%, and a pore volume of 0.37 cc/g.

Sample 2): In the preparation procedure of sample 1), trimethylamine hydrochloride 1
A resin was produced in the same manner except that 4.3 g (24% equivalent to chloromethyl group) was used.

This resin has a total anion exchange capacity of 4.78 meq/g,
The strong basic ion exchange capacity was 1.35 meq/g, the water content was 57%, and the pore volume was 0.37 cc/g.

Sample 3): In the preparation procedure of sample 1), trimethylamine hydrochloride 1
．． A resin was produced in the same manner except that 80 g (3% equivalent to chloromethyl group) was used. This resin had a total ion exchange capacity of 4.82 meq/g, a strong basic ion exchange capacity of 0.59 meq/g, a water content of 52%, and a pore volume of 0.38 cc/g.

Sample 4): A resin was produced in the same manner as in the preparation of Sample 1) without using trimethylamine hydrochloride. This resin is
The total ion exchange capacity was 4.81 meq/g, the strong basic ion exchange capacity was 0.50 a+eq/g, the water content was 50%, and the pore volume was 0.38 cc/g.

Sample 5): The chloromethylated copolymer in sample 1) was added to 250n1
of water, 100 ml of ethylene dichloride was added and stirred for 30 minutes, and then 188 ml of a 30% aqueous solution of trimethylamine was added over 1 hour at 20°C. Stirring was continued for an additional 3 hours at 20°C to carry out the amination reaction. After the amination reaction was completed, ethylene dichloride was distilled off, and the resulting resin was filtered off and thoroughly washed with water. The performance of this anion exchange resin is that the total anion exchange capacity is 4.07 meq/g.
, water content 66% and pore volume 0.42 cc/g.

For the above samples No. 1 to 5 and the sample of the commercially available weakly basic anion exchange resin Amberlite IRA-93, the crushing rate by acetic acid-caustic soda cycle test, the resin volume in the alkali regenerated form, and the resin volume in the chloride ion form The swelling ratio expressed as the ratio was determined and the results are shown in Table 1.

Table 1 *% equivalent of trimethylamine to chloromethyl group Example 2 Sample 6): Vinylbenzyl chloride produced by suspension polymerization of vinylhensyl chloride and divinylbenzene using methyl isobutyl carbinol as a pore-forming agent. 77 g of a dried divinylbenzene copolymer (divinylbenzene content: 3.5%) was suspended in water. The chlorine content was 21.9%.

To this, 4.8 g of trimethylamine hydrochloride (11% equivalent to chloromethyl group) was added and dissolved.

Then, 120 g of 50% aqueous sodium hydroxide solution was added over 1 hour while keeping the liquid temperature below 25°C, and the mixture was further stirred at 25°C for 2 hours. Then, 105 ml of a 50% aqueous solution of dimethylamine was added dropwise at the same temperature over 20 minutes. The reaction mixture was further stirred at 25°C for 1 hour, then warmed to 40°C and further stirred for 4 hours. After the amination reaction is completed, the resulting resin is filtered and thoroughly washed with water. It was sequentially washed with a normal aqueous hydrochloric acid solution IJZ, 0.5 It of demineralized water, and 11 parts of a 1N aqueous sodium hydroxide solution. The obtained resin was 5.0tme
It has a total anion exchange capacity of q/g, of which 0.94
The strong basic ion exchange capacity was meq/g, the water content was 66%, and the pore volume was 0.82 cc/g.

Sample 7): 9.6 g of trimethylamine hydrochloride used in the amination of sample 6) (21% based on chloromethyl group)
It was prepared in the same manner as the sample) except that the total anion exchange capacity was 5.05 meq/g, of which the strong basic ion exchange capacity was 1.32 meq/g, the water content was 69%, and the pore volume was 0.89 cc. /g of basic ion exchange resin was obtained.

Sample 6): Dimethylaminoethanol hydrochloride 6.3 instead of trimethylamine hydrochloride used in the amination of sample 6)
It was prepared in the same manner as sample 6) except that K (11% equivalent to chloromethyl group) was used, and the total ion exchange capacity was 5.
．． 07meq/g, including strong basic ion exchange capacity 0.7
7meq/g, moisture content 64%, pore volume 0.90c
A basic ion exchange resin of c/g was obtained.

Sample 9): Amination reaction was carried out using only dimethylamine without adding trimethylamine hydrochloride as in Sample 6).

The resulting resin has a total ion exchange capacity s, o+meq/g
, including strong basic ion exchange capacity 0.58 meq/g,
The water content was 63% and the pore volume was 0.91 cc/g.

The above samples No. 6 to 9 and Amberlite ■IRA-9
The crushing rate and swelling rate of each sample were determined and the results are shown in Table 2.

Example 3 Sample 10): A copolymer (molecular weight approximately 4.000) prepared from equal amounts of ethylene and propylene oxide was used as a pore-forming agent, and styrene and divinylbenzene were suspension polymerized. 74.2 g of the obtained styrene-divinylbenzene copolymer (divinylbenzene content 5.0%) was mixed with 139 g of ethylene dichloride and 225 g of chloromethyl methyl ether.
After stirring the copolymer in a mixed solution of 30 g to sufficiently swell the copolymer, 70 g of anhydrous aluminum chloride was added to the reaction solution at a temperature of 30°C.
Added below. Then, after stirring at 30°C for 6 hours,
Ice was added to stop the reaction, and the resulting chloromethylated copolymer was thoroughly washed with water and dried. The chlorine content is 20-. It was 8%. 104 g of this chloromethylated copolymer was suspended in water. To this, 10.0 g of trimethylamine hydrochloride
(17% equivalent to chloromethyl group), and further,
168 g of 50% aqueous caustic soda solution was added at 25° C. or below. After further stirring for 2 hours at 25°C, 147 tri of 50% dimethylamine aqueous solution was added dropwise at 25°C for 30 minutes.

1 hour at 25℃, 4 hours at 40℃, and 30 hours at 100℃
The amination reaction was carried out for minutes. The generated anion exchange resin was washed with water, washed with 1 N of IIcI, and 1 N of NaOH.
Step 12 was washed sequentially with deionized water.

The resulting resin had a total ion exchange capacity of 5.36 meq/g, of which the strongly basic ion exchange capacity was 1.35 meq/g. Moisture content is 47%, pore volume is 0.24cc
/g.

Sample 11): The same procedure as Sample 10) was carried out except that the trimethylamine hydrochloride of Sample 10) was not added. Anion exchange resin (total ion exchange capacity 5.45 meq/g, strongly basic ion exchange capacity 0.55 meq/g) , water content ff 142%, pore volume 0.24 cc/g).

Above samples No. 10 to 11 and Amberlite ■IRA
The crushing rate and swelling rate were determined for sample No.-93 and the results are shown in Table 3.

Table 3 Example 4 Sample 12): Styrene-divinylbenzene copolymer (divinylbenzene content 6.0%) obtained by suspension polymerization using toluene and polystyrene as pore-forming agents. Add chloromethylmethyl to 106 g. After adding 400 g of ether to sufficiently swell the copolymer, 102 g of anhydrous zinc chloride was added, and 40 g of anhydrous zinc chloride was added.
After reacting for 7 hours while stirring at °C, the mixture was thoroughly washed with water and dried to obtain 145 g of a chloromethylated copolymer. The chlorine content was 19.6%. This chloromethylated copolymer was suspended in water, and 9.6 g of trimethylamine hydrochloride was added.
(13% equivalent to chloromethyl group) was added. Next, add 240 g of 50% aqueous sodium hydroxide solution to the liquid 'JE125.
Add for 1 hour while keeping the temperature below ℃, then 25℃ for another 2 hours.
It was stirred with Then, a 50% aqueous solution of dimethylamine 20
9 ml was added at the same temperature over 30 minutes. The reaction mixture was further stirred at 25°C for 1 hour, then warmed to 40°C and stirred for 4 hours. The thus obtained resin was thoroughly washed with water, washed with a 1N aqueous hydrochloric acid solution, further washed with a 1N aqueous sodium hydroxide solution, and then washed again with water. The obtained resin is 5
．． Total anion exchange capacity of 10 meq/g, of which:
1.22 meq/g is the strong basic ion exchange capacity,
At 50% water content, the pore volume was 0.22 cc/g.

Sample 13): The reaction was carried out in the same manner as Sample 12) except that trimethylamine hydrochloride was not added during amination of Sample +2).

The obtained resin is as follows: 5. The total anion exchange capacity was ttmeq/g, of which 1.01 meq/g was the strongly basic ion exchange capacity, the water content was 46%, and the pore volume was 0.30 cc/g.

The crushing rate and swelling rate of the sample No. 12-13 were determined and the results are shown in Table 4.

Table 4

Claims (1)

[Scope of Claims] 1) A weakly basic anion exchange resin whose base material is a copolymer of a monovinyl aromatic monomer crosslinked with a polyvinyl monomer and has a haloalkyl group, and whose weakly basic anion exchange group is a dialkylamino group. 2 to 25% of quaternary amino groups based on tertiary amine to the haloalkylbenzene structural unit into which weakly basic anion exchange groups are introduced.
A physically stable weakly basic anion exchange resin that retains 2) When aminating a copolymer of a monovinyl aromatic monomer crosslinked with a polyvinyl monomer and having a haloalkyl group with a dialkylamine, a tertiary amine is reacted to form a haloalkylbenzene structural unit in the copolymer. Quaternary amino groups 2-25 based on tertiary amines
A method for producing a physically stable weakly basic anion exchange resin, characterized by introducing %. 3) A copolymer of a monovinyl aromatic monomer crosslinked with a polyvinyl monomer and having a haloalkyl group is reacted with a tertiary amine, and then a dialkylamine is reacted to form a tertiary compound with respect to the haloalkylbenzene structural unit in the copolymer. The method for producing an anion exchange resin according to claim 2, wherein 2 to 25% of quaternary amino groups based on amines are introduced. 4) The method for producing an anion exchange resin according to claim 3, wherein the polyvinyl monomer is a polyvinyl aromatic monomer or a polyvinyl aliphatic monomer. 5) The method for producing an anion exchange resin according to claim 3, wherein the tertiary amine is trimethylamine. 6) The method for producing an anion exchange resin according to claim 3, wherein the tertiary amine is dimethylaminoethanol.