JP2012157864A - Method for producing anion exchange resin, anion exchange resin, mixed bed resin, and method for producing ultra-pure water for cleaning electronic component/material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anion exchange resin in which residual impurities and formation of decomposed products are suppressed and the amount of leachables is reduced.SOLUTION: The method for producing the anion exchange resin comprises: a step (a) of copolymerizing a monovinyl aromatic monomer and a cross-linkable aromatic monomer to obtain a cross-linked copolymer; a step (b) of setting the content of a specific leachable compound to be ≤400 μg per 1 g cross-linked copolymer; a step (c) of haloalkylating the cross-linked copolymer to introduce the haloalkyl group of ≤80 mol% into the monovinyl aromatic monomer; a step (d) of removing the specific leachable compound from the haloalkylated cross-linked copolymer; and a step (e) of reacting the haloalkylated cross-linked copolymer with an amine compound.

Description

  The present invention relates to an anion exchange resin with little eluate and a method for producing the same, and a method for producing a mixed bed resin and ultrapure water for cleaning electronic parts and materials using the anion exchange resin.

Conventionally, ion exchange resins are used not only for purification of water but also in a wide range of industrial fields such as medicine, food, and chemical industries. In general, an ion exchange resin has a chemical structure in which an anion exchange group or a cation exchange group is introduced into a crosslinked three-dimensional polymer substrate. Examples of the anion exchange group include a primary to tertiary amino group, an ammonium group. Are well known.
An anion exchange resin is generally produced by reacting a copolymer of a monovinyl aromatic monomer and a crosslinkable aromatic monomer with a haloalkylating agent to introduce a haloalkyl group and then reacting with an amine compound.

  Although the performance required for an anion exchange resin varies depending on its use, it is commonly desired to have an appropriate exchange capacity and water content.

  Conventionally, ion exchange resins based on cross-linked copolymers have a problem that organic substances and the like are eluted when used. The eluate from these resins may cause coloration / toxicity of the liquid to be treated for separation or purification, inhibition of desalination due to contamination of the resin surface, generation of odors, reduction in processing amount, increase in moisture due to decomposition of the resin, etc. Cause incurring. Especially in the case of ultrapure water used for cleaning silicon wafers and electronic parts / materials, even if only a small amount of eluate is adsorbed on the silicon wafer surface, the product is Therefore, an anion exchange resin that has a remarkably small amount of eluate from the resin has been desired for ultrapure water production applications.

Causes of the elution from the resin are firstly impurities remaining during the production of the cross-linked copolymer, such as unpolymerized monomer components (monomers), poorly polymerized low polymer components (dimers, trimers). , Oligomers), free polymer components (linear polymers, polymer fine particles), the presence of by-products by polymerization reaction, and the like. For example, in the case of a styrene resin, styrene monomer, divinylbenzene, ethylvinylbenzene, etc. are used as unpolymerized monomer components, and styrene dimer, styrene trimer, styrene oligomer, etc. are used as free polymer components that are insufficiently polymerized. As a coalescing component, linear polystyrene, polystyrene fine particles and the like remain as impurities, and formaldehyde, benzaldehyde and the like remain as impurities as by-products due to the polymerization reaction, respectively.
However, there is no known effective means for preventing such impurities from remaining. Conventionally, in order to remove such impurities, distillation after ion exchange resin or synthetic adsorbent is produced or used. A process of washing it with water or the like is required, which causes a rise in cost and complication of the process.

Another cause of the generation of the eluate is that the cross-linked copolymer is decomposed by oxidation or the like with the passage of time during use or storage, resulting in a decomposed product.
Conventionally, in order to prevent the generation of such decomposition products, a technique for introducing a substituent imparting antioxidant ability has been proposed (see, for example, Patent Documents 1 to 3). However, the effect was not sufficient.

On the other hand, in terms of the exchange capacity of the ion exchange resin, in order to reduce the frequency of resin exchange as much as possible, a large exchange capacity has been desired in the past.
In particular, ion exchange resins for ultrapure water production are designed to be advantageous in terms of reaction rate by making the water to be treated easy to diffuse into the ion exchange resin because water treatment is performed at a high flow rate. There was a tendency. That is, in the ion exchange resin for producing ultrapure water, there is a tendency that a resin having not only a large exchange capacity but also a low degree of crosslinking and a high water content is desired.

European Patent Application No. 1077840 Japanese Patent Laid-Open No. 2-115046 JP-A-10-137736

  In view of the above background, an anion exchange resin using a cross-linked copolymer has been desired to have a technique for preventing the remaining of impurities and the generation of decomposition products and suppressing the generation of eluates during use.

  The present invention was devised in view of the above-mentioned problems, and its object is to suppress the remaining of impurities and the generation of decomposition products, an anion exchange resin with less eluate, a method for producing the same, and the anion exchange resin. It is to provide a method for producing mixed bed resin and ultrapure water for cleaning electronic parts / materials.

  As a result of intensive investigations in view of the above problems, the present inventors have a large exchange capacity as described above, and in relation to a specific water content rather than a conventional anion exchange resin that tends to have a high water content. It has been found that the above object can be effectively achieved by using an anion exchange resin having a small exchange capacity.

Moreover, in order to manufacture the anion exchange resin which has a smaller exchange capacity than the conventional anion exchange resin, it discovered that the following methods were effective.
(i) In an anion exchange resin obtained by using a step of haloalkylating a cross-linked copolymer of a monovinyl aromatic monomer and a cross-linkable aromatic monomer, the haloalkyl group introduction rate should be reduced in the haloalkylation step compared to the conventional method. .
(ii) The haloalkylation step is carried out under suppressed reaction conditions, for example, reaction conditions such as reducing the amount of catalyst, increasing the amount of reaction solvent, reducing catalyst concentration.

  The present inventors have also found that an anion exchange resin having a ΔTOC measurement value in a specific ultrapure water flow test that is not more than a specific value can effectively achieve the above object.

  Furthermore, it has been found that by using such an anion exchange resin and a mixed bed resin formed by using such an anion exchange resin, it is possible to produce high purity ultrapure water in which the generation of eluate is remarkably suppressed.

  That is, the gist of the present invention resides in the following [1] to [16].

（式(Ｉ)中、Ｚは、水素原子またはアルキル基を示す。ｌは自然数を示す。）
（ｃ）前記溶出性化合物の含有量が架橋共重合体１ｇに対して４００μｇ以下の架橋共重合体をハロアルキル化して、前記モノビニル芳香族モノマーに対して８０モル％以下のハロアルキル基を導入する工程
（ｄ）ハロアルキル化された架橋共重合体から、下記式(II)で示される溶出性化合物を除去する工程

（式(II)中、Ｘは、水素原子、ハロゲン原子、またはハロゲン原子で置換されていても良いアルキル基を示す。Ｙは、ハロゲン原子を示す。ｍ、ｎはそれぞれ独立に自然数を示す。）
（ｅ）前記溶出性化合物が除去されたハロアルキル化架橋共重合体をアミン化合物と反応させる工程 [1] A method for producing an anion exchange resin comprising the following steps (a) to (e):
(A) Step of obtaining a crosslinked copolymer by copolymerizing a monovinyl aromatic monomer and a crosslinkable aromatic monomer (b) The content of the eluting compound represented by the following formula (I) The process which makes 400 micrograms or less with respect to 1g of crosslinked copolymers with a crosslinkable aromatic monomer

(In the formula (I), Z represents a hydrogen atom or an alkyl group. L represents a natural number.)
(C) A step of introducing a haloalkyl group of 80 mol% or less with respect to the monovinyl aromatic monomer by haloalkylating a crosslinked copolymer having a content of the eluting compound of 400 μg or less with respect to 1 g of the crosslinked copolymer. (D) A step of removing the eluting compound represented by the following formula (II) from the haloalkylated crosslinked copolymer

(In formula (II), X represents a hydrogen atom, a halogen atom, or an alkyl group which may be substituted with a halogen atom. Y represents a halogen atom. M and n each independently represent a natural number. )
(E) reacting the haloalkylated crosslinked copolymer from which the eluting compound has been removed with an amine compound

[2] An anion exchange resin produced by the method for producing an anion exchange resin according to [1].

[3] The water content W _Cl (wt%) when measured in the Cl form and the exchange capacity Q _Cl (meq / mL-resin) per unit volume are any of the following formulas (1) to (5) An anion exchange resin characterized by
Q _Cl ≦ 1.25 (W _Cl <38) (1)
Q _Cl ≦ 1.36 (provided that 38 ≦ W _Cl <42) (2)
Q _Cl ≦ 1.2 (provided that 42 ≦ W _Cl <48) (3)
Q _Cl ≦ 1.1 (provided that 48 ≦ W _Cl <55) (4)
Q _Cl ≦ 0.8 (however, 55 ≦ W _Cl ) (5)

[4] The water content W _Cl (wt%) and the exchange capacity Q _Cl (meq / mL-resin) per unit volume when measured in the Cl form are represented by the following formula (8) [2] An anion exchange resin as described in 1.
Q _Cl ≦ −0.021 W _Cl +2.28 (8)

[5] The water content W _OH (wt%) when measured in the OH form and the exchange capacity Q _OH (meq / mL-resin) per unit volume are expressed by the following formula (6) or (7). An anion exchange resin characterized by that.
Q _OH ≦ 1.1 (W _OH <66) (6)
Q _OH ≦ 0.9 (provided that 66 ≦ W _OH ) (7)

[6] The water content W _OH (wt%) when measured in the OH form and the exchange capacity Q _OH (meq / mL-resin) per unit volume are represented by the following formula (9) [2] An anion exchange resin as described in 1.
Q _OH ≦ −0.018 W _OH +2.05 (9)

[7] An anion exchange resin obtained by haloalkylating a cross-linked copolymer obtained by copolymerizing a monovinyl aromatic monomer and a cross-linkable aromatic monomer, and then reacting with an amine compound, An anion exchange resin having 80 mol% or less of a haloalkyl group introduced to the monovinyl aromatic monomer.

（式(Ｉ)中、Ｚは、水素原子またはアルキル基を示す。ｌは自然数を示す。） [8] The anion exchange resin according to [7], wherein the content of the eluting compound represented by the following formula (I) in the crosslinked copolymer is 400 μg or less with respect to 1 g of the crosslinked copolymer.

(In the formula (I), Z represents a hydrogen atom or an alkyl group. L represents a natural number.)

[9] The anion exchange resin according to any one of [2] to [8], wherein ΔTOC in the ultrapure water flow test of (A) below is 0.5 ppb or less.
(A) Ultrapure water flow test (1) An empty measurement column having a diameter of 30 mm and a length of 1000 mm was filled with ultrapure water having a specific resistance of 18 MΩ · cm or more and a water temperature of 20 to 40 ° C. under room temperature conditions. The ultrapure water is passed at SV = 30 hr ⁻¹ , and the TOC concentration (TOC ₀ ) of the measurement column outlet water is measured.
(2) After pouring and filling 500 mL of the anion exchange resin into the measurement column, the ultrapure water was passed through the column at SV = 30 hr ⁻¹ at room temperature, and the TOC concentration of the measurement column outlet water after 20 hours. Measure (TOC ₁ ).
(3) Calculate ΔTOC by the following equation.
ΔTOC (ppb) = TOC ₁ −TOC ₀

[10] The anion exchange resin according to any one of [2] to [9], which is a spherical anion exchange resin and has a crushing strength per particle of 7.5 N or more.

[11] An anion exchange resin characterized in that ΔTOC in the ultrapure water flow test of (A) below is 0.2 ppb or less.
(A) Ultrapure water flow test (1) An empty measurement column having a diameter of 30 mm and a length of 1000 mm was filled with ultrapure water having a specific resistance of 18 MΩ · cm or more and a water temperature of 20 to 40 ° C. under room temperature conditions. The ultrapure water is passed at SV = 30 hr ⁻¹ , and the TOC concentration (TOC ₀ ) of the measurement column outlet water is measured.
(2) After pouring and filling 500 mL of the anion exchange resin into the measurement column, the ultrapure water was passed through the column at SV = 30 hr ⁻¹ at room temperature, and the TOC concentration of the measurement column outlet water after 20 hours. Measure (TOC ₁ ).
(3) Calculate ΔTOC by the following equation.
ΔTOC (ppb) = TOC ₁ −TOC ₀

[12] A spherical anion exchange resin, wherein the crushing strength per particle is 7.5 N or more.

[13] The anion exchange resin according to any one of [2] to [12], wherein the volume increase rate when mixed with the anion exchange resin is 150% or less before mixing.

[14] The anion exchange resin according to any one of [2] to [13], which is obtained by contacting a water-soluble polymer containing an anionic dissociative group.

[15] A mixed-bed resin formed using the anion exchange resin according to any one of [2] to [14].

[16] A method for producing ultrapure water for washing electronic parts / materials, wherein the anion exchange resin according to any one of [2] to [14] is used.

  According to the present invention, it is possible to provide an anion exchange resin with a small amount of eluate in which the remaining of impurities and decomposition products are suppressed, and this anion exchange resin is used as it is or by a mixed bed resin using the anion exchange resin. High purity ultrapure water for cleaning electronic parts and materials can be manufactured.

It is a graph which shows the relationship between the moisture content of the Cl-type anion exchange resin of an Example, a comparative example, and a reference example, and an exchange capacity. It is a graph which shows the relationship between the moisture content of OH type anion exchange resin of an Example, a comparative example, and a reference example, and an exchange capacity. It is a graph which shows the relationship between the exchange capacity of OH type anion exchange resin of an Example and a comparative example, and (DELTA) TOC in an ultrapure water washing test. It is a graph which shows the relationship between the exchange capacity of the Cl type anion exchange resin of an Example and a comparative example, and (DELTA) TOC in the ultrapure water washing test of OH type anion exchange resin prepared using this Cl type anion exchange resin. It is a graph which shows the time-dependent change of (DELTA) TOC in the ultrapure water flow test of Example 8 and Comparative Example 7.

  Hereinafter, embodiments of the present invention will be described in detail. In addition, the following description is an example of the embodiment of this invention, Comprising: This invention is not limited to the following description, unless the summary is exceeded.

（式(Ｉ)中、Ｚは、水素原子又はアルキル基を示す。ｌは自然数を示す。）
（ｃ）前記溶出性化合物の含有量が架橋共重合体１ｇに対して４００μｇ以下の架橋共重合体をハロアルキル化して、前記モノビニル芳香族モノマーに対して８０モル％以下のハロアルキル基を導入する工程
（ｄ）ハロアルキル化された架橋共重合体から、下記式(II)で示される溶出性化合物を除去する工程

（式(II)中、Ｘは、水素原子、ハロゲン原子、またはハロゲン原子で置換されていても良いアルキル基を示す。Ｙは、ハロゲン原子を示す。ｍ、ｎはそれぞれ独立に自然数を示す。）
（ｅ）前記溶出性化合物が除去されたハロアルキル化架橋共重合体をアミン化合物と反応させる工程 [1] Method for Producing Anion Exchange Resin The method for producing an anion exchange resin of the present invention includes the following steps (a) to (e).
(A) Step of obtaining a crosslinked copolymer by copolymerizing a monovinyl aromatic monomer and a crosslinkable aromatic monomer (b) The content of the eluting compound represented by the following formula (I) The process which makes 400 micrograms or less with respect to 1g of crosslinked copolymers with a crosslinkable aromatic monomer

(In the formula (I), Z represents a hydrogen atom or an alkyl group. L represents a natural number.)
(C) A step of introducing a haloalkyl group of 80 mol% or less with respect to the monovinyl aromatic monomer by haloalkylating a crosslinked copolymer having a content of the eluting compound of 400 μg or less with respect to 1 g of the crosslinked copolymer. (D) A step of removing the eluting compound represented by the following formula (II) from the haloalkylated crosslinked copolymer

(In formula (II), X represents a hydrogen atom, a halogen atom, or an alkyl group which may be substituted with a halogen atom. Y represents a halogen atom. M and n each independently represent a natural number. )
(E) reacting the haloalkylated crosslinked copolymer from which the eluting compound has been removed with an amine compound

[1-1] (a) Step of copolymerizing a monovinyl aromatic monomer and a crosslinkable aromatic monomer to obtain a crosslinked copolymer Examples of the monovinyl aromatic monomer according to the present invention include styrene, methylstyrene, and ethylstyrene. And halogen-substituted styrenes such as bromostyrene. These may be used alone or in combination of two or more. Among these, styrene or a monomer mainly composed of styrene is preferable.

Examples of the crosslinkable aromatic monomer include divinylbenzene, trivinylbenzene, divinyltoluene, divinylnaphthalene, and divinylxylene. These may be used alone or in combination of two or more. Of these, divinylbenzene is preferred.
Industrially produced divinylbenzene usually contains a large amount of by-product ethyl vinylbenzene (ethyl styrene), but such divinylbenzene can also be used in the present invention.

  The amount of the crosslinkable aromatic monomer used is usually 0.5 to 30% by weight, preferably 2.5 to 12% by weight, more preferably 4 to 10% by weight, based on the total monomer weight. As the amount of the crosslinkable aromatic monomer used increases and the degree of crosslinking increases, the oxidation resistance of the resulting anion exchange resin tends to improve. On the other hand, when the degree of crosslinking is too high, the leaching oligomers are easily removed by water washing in the subsequent step. In the latter stage (c) haloalkylation step, when the step of reducing the conversion rate of haloalkylation is carried out, the post-crosslinking reaction as a side reaction of haloalkylation is also suppressed. A method of increasing the addition amount of the crosslinkable aromatic monomer is also preferably used.

The copolymerization reaction of the monovinyl aromatic monomer and the crosslinkable aromatic monomer can be performed based on a known technique using a radical polymerization initiator.
As the radical polymerization initiator, one kind or two or more kinds such as dibenzoyl peroxide, lauroyl peroxide, t-butyl hydroperoxide, azobisisobutyronitrile are used. It is used in an amount of 05% by weight or more and 5% by weight or less.
The polymerization mode is not particularly limited, and the polymerization can be carried out in various modes such as solution polymerization, emulsion polymerization, suspension polymerization, etc. Among them, suspension in which a uniform bead-shaped copolymer is obtained. A polymerization method is preferably employed. The suspension polymerization method can be carried out by selecting a known reaction condition using a solvent, a dispersion stabilizer or the like generally used for the production of this type of copolymer.

The polymerization temperature in the copolymerization reaction is usually room temperature (about 18 ° C. to 25 ° C.) or more, preferably 40 ° C. or more, more preferably 70 ° C. or more, and usually 250 ° C. or less, preferably 150 ° C. or less. Preferably it is 140 degrees C or less. If the polymerization temperature is too high, depolymerization occurs at the same time, and the degree of polymerization completion is lowered. If the polymerization temperature is too low, the degree of polymerization completion will be insufficient.
The polymerization atmosphere can be carried out under air or under an inert gas, and nitrogen, carbon dioxide, argon or the like can be used as the inert gas.
Moreover, the polymerization method described in JP-A-2006-328290 can also be suitably used.
Moreover, the well-known method of obtaining the crosslinked copolymer of a uniform particle size can also be used conveniently.
For example, methods disclosed in JP 2002-35560 A, JP 2001-294602 A, JP 57-102905 A, and JP 3-249931 A can be suitably used.

[1-2] (b) A step of setting the content of the eluting compound having a specific structure to 400 μg or less with respect to 1 g of the crosslinked copolymer The method for producing an anion exchange resin of the present invention is described in [1-1] chapter. Prior to haloalkylation of the cross-linked copolymer obtained in (1), the content of the eluting compound represented by the following formula (I) (hereinafter sometimes referred to as “eluting compound (I)”) is used as the crosslinking copolymer. It includes a step of 400 μg or less, preferably 300 μg or less, more preferably 200 μg or less with respect to 1 g of the polymer.

（式(Ｉ)中、Ｚは、水素原子またはアルキル基を示す。ｌは自然数を示す。）

(In the formula (I), Z represents a hydrogen atom or an alkyl group. L represents a natural number.)

  Here, the alkyl group of Z is a C1-C8 alkyl group normally, Preferably, they are a methyl group, an ethyl group, a propyl group, and a butyl group, More preferably, they are a methyl group and an ethyl group.

  When the content of the eluting compound (I) in the cross-linked copolymer to be subjected to haloalkylation is more than 400 μg, it is possible to obtain an anion exchange resin with a small amount of the eluting material in which the remaining of impurities and the generation of decomposition products are suppressed. Can not. The content of the eluting compound (I) is preferably as small as possible, but the lower limit is usually about 50 μg.

  The eluting compound (I) according to the present invention is an unreacted or incomplete reaction product obtained when copolymerizing a monovinyl aromatic monomer and a crosslinkable aromatic monomer. This eluting compound (I) causes an ion exchange resin eluate at the time of product, and has a weight average molecular weight in terms of polystyrene of usually 200 or more, preferably 300 or more, and usually 1,000,000. 000 or less, preferably 100,000 or less. For example, in the case of a styrene resin, styrene dimer, styrene trimer, styrene oligomer, etc. are mentioned as low polymer components that are insufficiently polymerized, and linear polystyrene, polystyrene fine particles, etc. are mentioned as free polymer components. Moreover, as a by-product in the chain transfer reaction in the polymerization reaction, a low polymer component or a free polymer component to which a polymerization inhibitor contained in the monomer is bonded can be mentioned.

  The content of the eluting compound (I) in the crosslinked copolymer can be determined, for example, by an elution test described in the Examples section described later.

  The step (b) according to the present invention is performed simultaneously with the step (a) by adjusting the polymerization conditions in the step (a). Further, after the polymerization, the resulting crosslinked copolymer is washed to remove the eluting compound (I), thereby obtaining a crosslinked copolymer with a reduced content of the eluting compound.

  In the case of obtaining a cross-linked copolymer having a low content of the eluting compound by adjusting the polymerization conditions in the step (a), examples of the method for adjusting the polymerization conditions include the following.

[1-2-1] Adjustment of polymerization temperature As described above, if the polymerization temperature in the copolymerization reaction in the present invention is too high, depolymerization occurs at the same time, and the degree of completion of the polymerization is lowered. Conversely, if the polymerization temperature is too low, The degree of polymerization completion is insufficient, and a crosslinked copolymer having a low content of eluting compound cannot be obtained. Therefore, the polymerization temperature of the monovinyl aromatic monomer and the crosslinkable aromatic monomer is room temperature (about 18 ° C. to 25 ° C.) or higher, preferably 40 ° C. or higher, more preferably 70 ° C. or higher, and 250 ° C. or lower, preferably 150. It adjusts suitably in the range below 150 degreeC, More preferably 140 degreeC or less.

[1-2-2] Addition of deoxygenated monomer Deoxygenated monomer refers to a monomer in which the oxygen concentration in the monomer is lower than the saturated oxygen concentration, and a low polymer component (dimer, trimer, oligomer) that is insufficiently polymerized. In addition, it has a role of suppressing generation of free polymer components (linear polymers, polymer fine particles), by-products due to polymerization reaction, and the like. For example, the saturated oxygen concentration of a normal styrenic monomer is about 5% to 10% by weight. In the present invention, a deoxygenated monomer having a saturated oxygen concentration of less than 5% by weight, particularly 3% by weight or less is used. Is preferred.

  Specific methods for preparing the deoxygenated monomer include a method of bubbling the monomer with an inert gas, a method of degassing the membrane, a method of circulating the inert gas in the upper gas phase of the monomer storage tank, and a column such as silica gel. The method of doing is mentioned. Alternatively, commercially available deoxygenated monomers can also be used. Among them, the method of bubbling the monomer with an inert gas is preferable, and in this case, the inert gas used is preferably nitrogen, carbon dioxide, or argon. The deoxygenated monomer is stored in an inert gas atmosphere.

  The addition amount of the deoxygenated monomer is usually 10% by weight or more, preferably 50% by weight or more, more preferably 80% by weight or more based on the total amount of the monomer mixture. If the amount of deoxygenated monomer is too small, low polymer components (dimers, trimers, oligomers) that are insufficiently polymerized, free polymer components (linear polymers, polymer fine particles), and by-products due to polymerization reactions are generated. Become more.

[1-2-3] Use of monomer from which polymerization inhibitor has been removed By removing the polymerization inhibitor in the mixture of monovinyl aromatic monomer and crosslinkable aromatic monomer used in the polymerization, low polymerization A cross-linked copolymer that can suppress the generation of coalesced components (dimers, trimers, oligomers), free polymer components (linear polymers, polymer fine particles), by-products due to polymerization reaction, and has a low content of eluting compounds. Obtainable.

[1-2-4] Use of a Crosslinkable Aromatic Monomer with Less Impurities Usually, in a crosslinkable aromatic monomer, for example, divinylbenzene, non-polymerizable impurities such as diethylbenzene exist, and this is an eluting compound ( It is preferable that the crosslinkable aromatic monomer used for the polymerization has a low impurity content because it causes generation of I).
As such a crosslinkable aromatic monomer having a low impurity content, it is preferable to select and use a specific grade such that the crosslinkable aromatic monomer content (purity) is 57% by weight or more. In addition, a crosslinkable aromatic monomer having a small impurity content can be obtained by removing impurities by, for example, distillation.

  The crosslinkable aromatic monomer content (purity) of the crosslinkable aromatic monomer used in the present invention is particularly preferably 60% by weight or more, more preferably 80% by weight or more, and is non-polymerizable in the crosslinkable aromatic monomer. The impurity content is usually 5% by weight or less, preferably 3% by weight or less, more preferably 1% by weight or less per monomer weight. If this impurity content is too high, it tends to cause a chain transfer reaction to impurities during polymerization, so the amount of eluting oligomer (polystyrene) remaining in the polymer after polymerization may increase, and the eluting compound content A small amount of a crosslinked copolymer cannot be obtained.

[1-2-5] Adjustment of use amount of crosslinkable aromatic monomer As described above, the more the crosslinkable aromatic monomer used for copolymerization, the more the oxidation resistance of the resin tends to be improved. If the degree of crosslinking is too high, extraction and removal of the eluting oligomer is likely to be incomplete in the subsequent step, and it becomes difficult to obtain a crosslinked copolymer having a low content of the eluting compound. Therefore, the use amount of the crosslinkable aromatic monomer is appropriately adjusted in the range of 0.5 to 30% by weight, preferably 2.5 to 12% by weight, more preferably 4 to 10% by weight based on the total monomer weight. .

  In addition, when the step (b) is performed after the step (a), the following cleaning step can be employed.

[1-2-6] Step of washing cross-linked copolymer In the present invention, if necessary, the cross-linked copolymer produced from the monovinyl aromatic monomer and the cross-linkable aromatic monomer in the step (a), The eluting compound (I) can be removed by washing with a solvent before the (c) haloalkylation step described later.

This washing method can be carried out by a column method in which a crosslinked copolymer is packed in a column and a solvent is passed, or by a batch washing method.
The washing temperature is usually room temperature (20 ° C) or higher, preferably 30 ° C or higher, more preferably 50 ° C or higher, particularly preferably 90 ° C or higher, and usually 150 ° C or lower, preferably 130 ° C or lower, more preferably 120 ° C or lower. It is. If the washing temperature is too high, the cross-linked copolymer will be decomposed. If the washing temperature is too low, the washing efficiency is lowered.
The contact time with the solvent is usually 5 minutes or longer, preferably 1 hour or longer, more preferably 2 hours or longer, and usually 4 hours or shorter. If the contact time with the solvent is too short, the cleaning efficiency is lowered, and if the time is too long, the productivity is lowered.

  Solvents used for washing include aliphatic hydrocarbons having 5 or more carbon atoms, such as pentane, hexane, and heptane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, diethylbenzene, and the like; alcohols such as methanol, Ethanol, propanol, butanol, etc .; ketones such as acetone, methyl ethyl ketone, etc .; ethers such as dimethyl ether, diethyl ether, methylal, etc .; chlorinated solvents such as dichloromethane, chloroform, carbon tetrachloride, dichloroethane, trichloroethane, etc .; phenols such as Such as phenol, and the like. These may be used alone or in combination of two or more. Of these, benzene, toluene, xylene, acetone, diethyl ether, methylal, dichloromethane, chloroform, dichloroethane, and trichloroethane are preferable. Further, a method of mixing these solvents with water, raising the temperature, and washing in an azeotropic state can also be employed.

[1-3] (c) Step of haloalkylating the crosslinked copolymer The crosslinked copolymer obtained through the steps of [1-1] and [1-2] is then free in a swollen state. A haloalkylating agent is reacted to haloalkylate in the presence of a Dell-Crafts reaction catalyst.

  In order to swell the crosslinked copolymer, a swelling solvent such as dichloroethane can be used. In the present invention, it is preferable to swell only with a haloalkylating agent in order to sufficiently promote halomethylation.

  Examples of Friedel-Crafts reaction catalysts include Lewis acid catalysts such as zinc chloride, iron (III) chloride, tin (IV) chloride, and aluminum chloride. These catalysts may be used individually by 1 type, and may mix and use 2 or more types.

  In order to make the haloalkylating agent act not only as a reaction reagent but also as a swelling solvent for the copolymer, it is preferable to use one having a high affinity with the copolymer, for example, chloromethyl methyl ether, methylene chloride, bis ( And halogen compounds such as chloromethyl) ether, polyvinyl chloride, bis (chloromethyl) benzene, etc., and these may be used alone or in combination of two or more, but more preferably. Is chloromethyl methyl ether. That is, the haloalkylation in the present invention is preferably chloromethylation.

  In the anion exchange resin of the present invention, the introduction rate of the haloalkyl group in this step is 80% or less, preferably 75 with respect to the theoretical halogen content when the monovinyl aromatic monomer is assumed to be 100 mol% haloalkylated. % Or less, more preferably 70% or less. Increasing this haloalkyl group introduction rate (percentage of the proportion of halogen atoms introduced relative to the theoretical halogen content assuming that the monovinyl aromatic monomer is haloalkylated at 100 mol%) increases the cross-linking The main chain of the coalescence breaks or excessively introduced haloalkyl groups are liberated after introduction and cause impurities. By limiting the introduction rate of haloalkyl groups in this way, the generation of impurities is suppressed and eluted. An anion exchange resin with a small amount can be obtained.

  In the present invention, by suppressing the introduction amount of the haloalkyl group, side reactions in the haloalkylation step are also reduced, so that it is considered that an eluting oligomer is hardly generated. Moreover, it is thought that the by-product which generate | occur | produces will also reduce the substance which is hard to wash and remove in a post process compared with a conventional formulation. As a result, an anion exchange resin with a remarkably small amount of eluate can be obtained.

Hereinafter, a specific method for introducing a haloalkyl group will be described in detail.
The amount of the haloalkylating agent used is selected from a wide range depending on the degree of crosslinking of the crosslinked copolymer and other conditions, but is preferably an amount that at least sufficiently swells the crosslinked copolymer. 1 times or more, preferably 2 times or more, usually 50 times or less, preferably 20 times or less.

  The amount of the Friedel-Crafts reaction catalyst used is usually 0.001 to 10 times, preferably 0.1 to 1 times, more preferably 0.1 to 0.7 times the weight of the crosslinked copolymer. Double the amount.

  Examples of means for setting the haloalkyl group introduction rate to the crosslinked copolymer to 80% or less include means for lowering the reaction temperature, using a catalyst having low activity, and reducing the amount of catalyst added. That is, the main factors affecting the reaction between the cross-linked copolymer and the haloalkylating agent include reaction temperature, activity (type) of Friedel-Crafts reaction catalyst and its addition amount, haloalkylating agent addition amount, and the like. Therefore, the haloalkyl group introduction rate can be controlled by adjusting these conditions.

The reaction temperature varies depending on the type of Friedel-Crafts reaction catalyst to be used, but it is usually 0 ° C. or higher and must be suppressed to 55 ° C. at the maximum.
The preferred reaction temperature range varies depending on the haloalkylating agent and Friedel-Crafts reaction catalyst used. For example, when chloromethyl methyl ether is used as the haloalkylating agent and zinc chloride is used as the Friedel-Crafts reaction catalyst. The temperature is usually 30 ° C. or higher, preferably 35 ° C. or higher, and is usually 50 ° C. or lower, preferably 45 ° C. or lower. At this time, excessive introduction of the haloalkyl group can be suppressed by appropriately selecting the reaction time and the like.

  In the haloalkyl group introduction reaction, the post-crosslinking reaction also proceeds at the same time, and there is a meaning of securing the strength of the final product by the post-crosslinking reaction, so it is better to secure a certain time for the haloalkyl group introduction reaction. The reaction time for haloalkylation is preferably 30 minutes or longer, more preferably 3 hours or longer, and even more preferably 5 hours or longer. Further, it is preferably 24 hours or less, more preferably 12 hours or less, and further preferably 9 hours or less.

  The haloalkylation reaction described above may be performed in the same reaction system by changing the reaction temperature and / or the amount of catalyst stepwise or continuously from the first reaction stage to the second reaction stage.

[1-4] (d) Step of removing an eluting compound having a specific structure from a haloalkylated cross-linked copolymer (haloalkylated cross-linked copolymer) The resulting haloalkylated cross-linked copolymer is then subjected to a treatment for removing the eluting compound represented by the following formula (II) (hereinafter sometimes referred to as “eluting compound (II)”), thereby producing a haloalkylated cross-linking copolymer. The haloalkylated cross-linking copolymer is preferably used so that the content of the eluting compound (II) is preferably 400 μg or less, more preferably 100 μg or less, particularly preferably 50 μg or less, particularly preferably 30 μg or less with respect to 1 g of the copolymer. It is preferred to purify the polymer. When the content of the eluting compound (II) is large, it is not possible to obtain an anion exchange resin with a small amount of the eluting material in which the remaining of impurities and the generation of decomposition products are suppressed. Although the content of the eluting compound (II) is preferably as small as possible, the lower limit is usually about 30 μg.

（式(II)中、Ｘは、水素原子、ハロゲン原子、またはハロゲン原子で置換されていても良いアルキル基を示す。Ｙは、ハロゲン原子を示す。ｎ、ｍはそれぞれ独立に自然数を示す。）

(In formula (II), X represents a hydrogen atom, a halogen atom, or an alkyl group which may be substituted with a halogen atom. Y represents a halogen atom. N and m each independently represent a natural number. )

Here, the alkyl group which may be substituted with the halogen atom of X is usually an alkyl group having 1 to 10 carbon atoms or a haloalkyl group, preferably a methyl group, an ethyl group, a propyl group, a butyl group, a halomethyl group. , A haloethyl group, a halopropyl group, and a halobutyl group, and more preferably a methyl group, an ethyl group, a halomethyl group, and a haloethyl group.
N is usually 1 or more, usually 8 or less, preferably 4 or less, and more preferably 2 or less.

In addition, the eluting compound (II) according to the present invention causes an ion exchange resin eluate at the time of product, like the eluting compound (I). The breakdown includes a substance derived from an eluting compound originally contained in the cross-linked copolymer serving as a matrix for haloalkylation and a substance generated at the stage of haloalkylation.
The substance derived from the eluting compound originally contained in the cross-linked copolymer serving as the matrix of the haloalkylation is a haloalkylated product of the eluting compound (I) described in the item [1-2] (b), It corresponds to the substance shown in II). In addition, substances into which a plurality of haloalkyl groups are introduced are also included.
Examples of the substance generated at the stage of haloalkylation include a substance generated along with the cleavage of the carbon-carbon bond by the reverse reaction of the Friedel-Crafts reaction, which is also represented by the above formula (II). For example, low-molecular and high-molecular polymers and oligomer components generated by cleavage of the main chain of the crosslinked copolymer.

  The weight average molecular weight of these eluting compounds (II) in terms of polystyrene sulfonic acid is usually 200 or more, preferably 300 or more, and usually 1,000,000 or less, preferably 100,000 or less. For example, in the case of a styrene resin, the eluting compound (II) is a styrene dimer, styrene trimer, haloalkylated product of a styrene oligomer or the like as a low polymer component that is insufficiently polymerized, and linear polystyrene or polystyrene fine particles as a free polymer component. And haloalkylated compounds. Further, as a by-product in the chain transfer reaction in the polymerization reaction, there may be mentioned a haloalkylated product of a low polymer component or a free polymer component to which a polymerization inhibitor contained in the monomer is bound.

  Such eluting compound (II) can be removed, for example, by washing the haloalkylated cross-linked copolymer obtained in step (c) with a solvent.

This washing method can be performed by a column method in which a haloalkylated crosslinked copolymer is packed in a column and water is passed through the solvent, or by a batch washing method.
The washing temperature is usually room temperature (20 ° C) or higher, preferably 30 ° C or higher, more preferably 50 ° C or higher, particularly preferably 90 ° C or higher, and usually 150 ° C or lower, preferably 130 ° C or lower, more preferably 120 ° C or lower. It is. If the washing temperature is too high, the polymer will be decomposed and haloalkyl groups may be removed. If the washing temperature is too low, the washing efficiency is lowered.
The contact time with the solvent is usually 5 minutes or longer, preferably the time for which the crosslinked copolymer swells 80% or more, and is usually 4 hours or shorter. If the contact time is too short, the cleaning efficiency is lowered, and if the time is too long, the productivity is lowered.

  Solvents used for washing include aliphatic hydrocarbons having 5 or more carbon atoms, such as pentane, hexane, and heptane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, diethylbenzene, and the like; alcohols such as methanol, Ethanol, propanol, butanol, etc .; ketones such as acetone, methyl ethyl ketone, etc .; ethers such as dimethyl ether, diethyl ether, methylal, etc .; chlorinated solvents such as dichloromethane, chloroform, carbon tetrachloride, dichloroethane, trichloroethane, etc .; phenols such as Such as phenol, and the like. These may be used alone or in combination of two or more. Of these, benzene, toluene, xylene, acetone, diethyl ether, methylal, dichloromethane, chloroform, dichloroethane, and trichloroethane are preferable.

[1-5] (e) Step of reacting haloalkylated crosslinked copolymer with amine compound In the anion exchange resin of the present invention, the haloalkylated crosslinked copolymer from which the eluting compound (II) has been removed as described above. By reacting the compound with an amine compound, an amino group is introduced to produce an anion exchange resin, but the introduction of the amino group can also be easily carried out by a known technique.
For example, a method in which a haloalkylated cross-linked copolymer is suspended in a solvent and reacted with trimethylamine or dimethylethanolamine can be mentioned.

As the solvent used in the introduction reaction, for example, water, toluene, dioxane, dimethylformamide, dichloroethane or the like is used alone or in combination.
Thereafter, the anion exchange resin can be obtained by changing the salt form to various anion forms by a known method.

As described above, when the reaction conditions are suppressed in the haloalkylation step to control the introduction rate of the haloalkyl group, the post-crosslinking method may be weakened. As a countermeasure in this case, in the step (a), the amount of the crosslinkable aromatic monomer added in advance is larger than the amount necessary for obtaining a resin having a desired moisture content in the conventional anion exchange resin production method. By synthesizing a copolymer and then taking the haloalkylation conditions as in the present invention, the haloalkylation introduction rate can be suppressed to 80% or less.
By adding the above-described operation, the crosslink density of the haloalkylated cross-linked copolymer is controlled, and when the amine is reacted to form an anion exchange resin, the desired water content and strength can be obtained.

[1-6] Method for Producing OH Type Anion Exchange Resin The OH type anion exchange resin of the present invention is produced by regenerating the Cl type anion exchange resin synthesized above into a OH form by a known regeneration method. can do.
As this regeneration method, for example, the method described in JP-A-2002-102719 can be suitably used.

[1-7] Purification method of OH-type anion exchange resin The OH-type anion exchange resin of the present invention is a Cl-type or OH-type anion exchange resin produced by the method up to [1-5] or [1-6]. Thereafter, a known elution reduction method can be applied to obtain an anion exchange resin for ultrapure water.
As this purification method, for example, the method described in JP-A No. 2002-102719 can be suitably used.
Specifically, a method of washing an anion exchange resin in the presence of an alkaline solution, a method of washing with hot water using a column, or a method of washing with a solvent can be suitably used. In addition, after producing a Cl-type or OH-type anion exchange resin by the method up to [1-5] or [1-6], a known method for reducing the metal content is applied to the obtained anion exchange resin as necessary. You can also

[1-8] Other treatments The anion exchange resin of the present invention obtained as described above may be further subjected to various treatments usually performed as a treatment for anion exchange resins. For example, the anti-leaking process may be performed by a known method.

  That is, in general, when an anion exchange resin is used in a mixed bed with a cation exchange resin, the mixed bed resin formed of the cation exchange resin and the anion exchange resin because of the “entanglement phenomenon” that is electrically entangled with the cation exchange resin. Since the volume of the material increases excessively, it becomes a problem in terms of handling.

  Therefore, by carrying out the anti-entanglement treatment on the anion exchange resin of the present invention, the volume increase rate when mixed with the cation exchange resin is 150% or less, preferably 130% or less, more preferably 110% or less before mixing. It is preferable to do. The volume increase rate is a percentage of the ratio of the volume of the mixed bed resin after mixing to the total volume before mixing the anion exchange resin and the cation exchange resin.

As this anti-entanglement treatment, a known method described in JP-A-10-202118 or JP-A-2002-102719 can be applied.
Specifically, it is usually 0.01 mmol / L or more, preferably 0.1 mmol / L or more, and usually 10 mmol / L or less, preferably 2 mmol / L or less per 1 liter of anion exchange resin. It can be carried out by treatment with a water-soluble polymer containing a group.

  Examples of the water-soluble polymer containing an anionic dissociation group suitable for use in the present invention include known water-soluble polymers described in JP-A-10-202118 and JP-A-2002-102719. Preferably, polystyrene sulfonic acid, polyvinyl benzyl sulfonic acid, polymaleic acid, poly (meth) acrylic acid, polyvinyl sulfonic acid and the like can be mentioned. Of these, polystyrene sulfonic acid and polyvinyl sulfonic acid are preferably used. These may be used alone or in combination of two or more.

[2] Anion exchange resin The anion exchange resin of the present invention has the following physical properties and characteristics, and is preferably manufactured by the above-described method for manufacturing an anion exchange resin of the present invention. There is no limit to the method.

The shape and structure of the anion exchange resin of the present invention are not particularly limited. For example, the shape may be a fiber, powder, plate, membrane or the like in addition to commonly used beads. Various shapes are also included.
The water content of the anion exchange resin of the present invention is usually 25% by weight or more and 75% by weight or less, but practically, it is preferably in the range of 30% by weight or more and 60% by weight or less.

[2-1] Moisture content and exchange capacity [2-1-1] Moisture content and exchange capacity per unit volume when measured in Cl form Anion exchange resin of the present invention or anion exchange of a preferred embodiment of the present invention Regarding the resin, the water content W _Cl (wt%) and the exchange capacity per unit volume Q _Cl (meq / mL-resin) when measured in the Cl form are any of the following formulas (1) to (5): It is represented by

Q _Cl ≦ 1.25 (W _Cl <38) (1)
Q _Cl ≦ 1.36 (provided that 38 ≦ W _Cl <42) (2)
Q _Cl ≦ 1.2 (provided that 42 ≦ W _Cl <48) (3)
Q _Cl ≦ 1.1 (provided that 48 ≦ W _Cl <55) (4)
Q _Cl ≦ 0.8 (however, 55 ≦ W _Cl ) (5)

The water content W _Cl (% by weight) of this anion exchange resin and the exchange capacity per unit weight Q _Cl (meq / mL-resin) are preferably any of the following formulas (1 ′) to (5 ′): expressed.

Q _Cl ≦ 1.23 _{(however, W Cl <38) ... (} 1 ')
Q _Cl ≦ 1.36 (provided that 38 ≦ W _Cl <42) (2 ′)
Q _Cl ≦ 1.2 (provided that 42 ≦ W _Cl <48) (3 ′)
Q _Cl ≦ 1.1 (provided that 48 ≦ W _Cl <55) (4 ′)
Q _Cl ≦ 0.8 (however, 55 ≦ W _Cl ) (5 ′)

Alternatively, for the anion exchange resin of the present invention or the anion exchange resin of the preferred embodiment of the present invention, the water content W _Cl (wt%) when measured in the Cl form and the exchange capacity per unit volume Q _Cl (meq / mL− (Resin) is represented by the following formula (8).
Q _Cl ≦ −0.021 W _Cl +2.28 (8)

As described above, general anion exchange resins tend to have a high moisture content and a large exchange capacity.
The Cl-type anion exchange resin of the present invention or the Cl-type anion exchange resin of the preferred embodiment of the present invention has the above formulas (1) to (5), preferably (1 ′) to (5 ′), or the above formula (8). ), The exchange capacity is small as compared with a conventional anion exchange resin having a similar moisture content.

  In this way, compared to conventional anion exchange resins having a similar water content, the Cl-type anion exchange resin having a small exchange capacity prevents residual impurities and generation of decomposition products compared to conventional resins, The reason for suppressing the generation of eluate during use is estimated as follows.

(I) Reduction of Multifunctional Impurity Impurities In the haloalkylation reaction, a plurality of haloalkyl groups are also introduced into one monomer unit of the crosslinked copolymer. If such impurities are present, the solubility in the organic solvent is low, so that a great load is imposed on the removal with the organic solvent. Further, since the steric hindrance at the time of amination is large, all of a plurality of haloalkyl groups may remain without being aminated, and as a result, impurities with low water washability (hereinafter referred to as “multifunctionalized impurities”). ) Remains in the final product, and is estimated to be the cause of elution during use.
On the other hand, the anion exchange resin of the present invention does not have an excess of exchange groups as compared with conventional resins, and it is considered that the amount of polyfunctionalized impurities is reduced.

(ii) Reduction of the amount of elution by reducing the exchange group itself As one of the eluates from an anion exchange resin, amines such as trimethylamine are known. This elution of amines is attributed to the loss of exchange groups.
On the other hand, since the anion exchange resin of the present invention has a small amount of exchange groups as compared with conventional resins, it is considered that elution due to the exchange group dropping off decreases.

(iii) Suppression of exchange group removal by selective haloalkylation Ordinary anion exchange resins may have a plurality of exchange groups per monomer unit, and the steric hindrance makes it easy to cause exchange group removal. It is thought that. Therefore, in order to suppress the elimination of such exchange groups, one exchange group should be introduced for each monomer unit.
Therefore, since the anion exchange resin of the present invention has a smaller exchange capacity than conventional resins, it is less likely to have a plurality of exchange groups per monomer unit. Thereby, since the steric hindrance between the exchange groups is reduced, the elimination of the exchange groups is reduced, and it is considered that the elution resulting from the exchange group removal is reduced during use.

(iv) Inhibition of carbon-carbon bond cleavage during haloalkylation In the haloalkylation step, a Lewis acid is usually added to carry out a Friedel-Crafts reaction (generation of a carbon-carbon bond). In this reaction, the carbon-carbon bond is also cleaved by the reverse reaction, and therefore, the main chain of the crosslinked copolymer is cleaved to generate an eluate of a low-molecular oligomer or a high-molecular linear polymer.
On the other hand, the anion exchange resin having a small number of exchange groups according to the present invention is considered to have less eluate because such carbon-carbon bond cleavage and main chain cleavage are reduced.

Incidentally, exchange capacity Q _Cl and water content W _Cl of Cl type anion exchange resin according to the present invention, the analysis in the following manner, is measured.

[Measurement method of exchange capacity _QCl and water content _WCl ]
An anion exchange resin is packed in a column, and a 5% by weight aqueous NaCl solution having a volume 25 times the resin volume is passed through the column to convert the anion type to the Cl type. 10 ml of this resin is taken, packed in a column, and 2N NaOH aqueous solution is passed through 75 times the amount of resin to convert the anion type to OH type. Wash thoroughly with demineralized water until the washing filtrate becomes neutral, and then pass 5% by weight of 5% by weight NaCl aqueous solution to collect all the effluent. By titrating the effluent with hydrochloric acid, to calculate the exchange capacity _Q Cl (meq / _mL- resin).

Further, the resin whose anion type is converted to Cl type is centrifuged to remove the adhering water, and then the weight is measured. Thereafter, it is dried for about 4 hours in a constant temperature dryer at 105 ± 2 ° C. After standing to cool in a desiccator, the weight is measured and the water content W _Cl (% by weight) is calculated.

In the anion exchange resin according to the present invention, the exchange capacity Q _Cl and the water content W _Cl satisfy the above formulas (1) to (5), preferably (1 ′) to (5 ′), or the above formula (8). For example, in the case of an anion exchange resin obtained by haloalkylating a crosslinked copolymer obtained by copolymerizing a monovinyl aromatic monomer and a crosslinkable aromatic monomer and then reacting with an amine compound,
(A) A method of reducing the introduction rate of haloalkyl groups in the stage of haloalkylation compared to the prior art (b) The stage of the haloalkylation is controlled under controlled reaction conditions, for example, reduction of catalyst amount, increase of reaction solvent, reduction of catalyst concentration. (C) A method of suppressing the content of a specific eluting compound to a certain value or less at the stage of a cross-linked copolymer of a monovinyl aromatic monomer and a cross-linkable aromatic monomer, etc. .

[2-1-2] Moisture content when measuring in OH form and exchange capacity per unit volume The anion exchange resin of the present invention or the anion exchange resin of a preferred embodiment of the present invention is water content when measured in the OH form. The content W _OH (% by weight) and the exchange capacity Q _OH (meq / mL-resin) per unit volume are represented by the following formula (6) or (7).

Q _OH ≦ 1.1 (W _OH <66) (6)
Q _OH ≦ 0.9 (provided that 66 ≦ W _OH ) (7)

Alternatively, for the anion exchange resin of the present invention or the anion exchange resin of the preferred embodiment of the present invention, the water content W _OH (wt%) when measured in the OH form and the exchange capacity Q _OH per unit volume (meq / mL− (Resin) is represented by the following formula (9).
Q _OH ≦ −0.018 W _OH +2.05 (9)

As described above, the conventional anion exchange resin or the OH type anion exchange resin of the preferred embodiment of the present invention tends to have a high moisture content and a large exchange capacity.
The OH type anion exchange resin of the present invention is compared with the conventional anion exchange resin having the same water content as defined by the formula (6), (7) or the formula (9). The exchange capacity is small.

  In this way, OH-type anion exchange resin with a small exchange capacity compared to a conventional anion exchange resin having a similar moisture content prevents impurities from remaining and generation of decomposition products, compared to conventional resins, The reason for suppressing the generation of eluate during use is as described above in the description of the Cl-type anion exchange resin of the present invention.

The exchange capacity Q _OH and the water content W _OH of the _{OH type} anion exchange resin according to the present invention are analyzed and measured by the following method.

[Measurement method of exchange capacity Q _OH and moisture content W _OH ]
Take 10 ml of OH-type anion exchange resin, pack it in a column, and pass 5% by weight 5% NaCl aqueous solution through the resin to collect all the effluent. By titrating the effluent with hydrochloric acid, the exchange capacity Q _OH (meq / mL-resin) is calculated.

In addition, the water content W _OH is equivalent to a digital automatic titration apparatus (for example, “Karl Fischer KF07 Model” manufactured by Mitsubishi Chemical Corporation) by the Karl Fischer method after removing water adhering by centrifuging the OH anion exchange resin. ) Using the following procedure.
About 5 g of a sample is accurately measured in a 20 mL weighing bottle, and about 0.1 g is quickly taken with a spoon, and it is put into about 30 mL of methanol whose moisture is set to “0” with a Karl Fischer reagent. Next, the Karl Fischer reagent is dropped while stirring, and the water content W _OH (% by weight) is calculated with the point where the instruction of the ammeter is stopped for 30 seconds after the last drop is added, as the end point.

In the OH type anion exchange resin according to the present invention, the method for satisfying the above formula (6), (7), or the above formula (9) for the exchange capacity Q _OH and the water content W _OH is described in the present invention. The exchange capacity Q _Cl and the water content W _Cl of the _Cl- type anion exchange resin satisfy the above formulas (1) to (5), preferably the above formulas (1 ′) to (5 ′) or the above formula (8). It is the same as the method of making it.

[2-2] ΔTOC in ultrapure water flow test
In the anion exchange resin of the present invention, ΔTOC in the ultrapure water flow test of the following (A) is preferably 0.5 ppb or less, and more preferably 0.2 ppb or less.

(A) Ultrapure water flow test (1) An empty measurement column having a diameter of 30 mm and a length of 1000 mm was filled with ultrapure water having a specific resistance of 18 MΩ · cm or more and a water temperature of 20 to 40 ° C. under room temperature conditions, Ultrapure water is passed at SV = 30 hr ⁻¹ , and the TOC concentration (TOC ₀ ) of the measurement column outlet water is measured.
(2) After pouring and filling 500 mL of the anion exchange resin into the measurement column, the ultrapure water was passed through the column at SV = 30 hr ⁻¹ at room temperature, and the TOC concentration of the measurement column outlet water after 20 hours. Measure (TOC ₁ ).
(3) Calculate ΔTOC by the following equation.
ΔTOC (ppb) = TOC ₁ −TOC ₀

As the measurement device for the specific resistance and TOC concentration in the above (A) ultrapure water flow test, commercially available measuring instruments are used to such an extent that the technical significance of the present invention is not lost. In the case of an anion exchange resin used for water production, a highly accurate resin is desirable.
An example of the specific resistance measuring device is “AQ-11” manufactured by DKK. Examples of the TOC measuring instrument include “A-1000XP type”, “A-1000 type”, “A-100SE”, “S20P” manufactured by Anatel, and “500RL type” manufactured by Seabass.

  In the case where ΔTOC in the above-mentioned (A) ultrapure water flow test exceeds 0.5 ppb, as an anion exchange resin for producing ultrapure water, particularly ultrapure water for cleaning electronic parts and materials such as semiconductors, There is a problem of purity reduction due to eluate, which is not preferable.

[2-3] Volume increase rate The anion exchange resin of the present invention has a volume increase rate of 150% or less, preferably 130, when mixed with the cation exchange resin by carrying out the anti-entanglement treatment as described above. % Or less, more preferably 10% or less. If the volume increase rate is too large, the volume of the mixed bed resin formed by the anion exchange resin and the cation exchange resin increases excessively, which causes a problem in handling.
Therefore, it is preferable to perform the above-described entanglement prevention treatment as necessary so as to achieve such a volume increase rate.

The volume increase rate of the anion exchange resin is measured by the following method.
<Volume increase rate measurement method>
1) Weigh 1 part of anion exchange resin into a graduated cylinder in a slurry state in water.
2) Weigh 1 part of cation exchange resin into a graduated cylinder in a slurry state in water.
3) Pour the cation exchange resin into the anion exchange resin, shake it up and down 10 times, and measure the volume of the obtained mixed bed resin.
4) The volume increase rate is determined by the following equation.
(Volume increase rate)% = (mixed bed resin volume) / (anion exchange resin volume)
+ Cation exchange resin volume) x 100

[2-4] Crushing strength The anion exchange resin of the present invention has a crushing strength per particle of 7.5 N or more, preferably 9 N or more, more preferably 10 N or more, and usually 50 N or less, preferably 30 N. The following is preferable.

Thus, the anion exchange resin of the present invention, which has a higher crushing strength than ordinary anion exchange resins, has less eluate.
The reason why the anion exchange resin having a high crushing strength has less eluate is estimated as follows.
As an example of an anion exchange resin containing no exchange groups (that is, a cross-linked copolymer of a monovinyl aromatic monomer and a polyvinyl aromatic monomer), a cross-linked copolymer of styrene and divinylbenzene is usually hard particles of 20 N or more. And ΔTOC is close to zero because it does not contain any water-soluble eluate.
Therefore, in the case of an anion exchange resin having a lower exchange capacity than a conventional resin as in the present invention, it is considered that a crushing strength is high and a ΔTOC in the above-mentioned (A) ultrapure water flow test is low. It is done.

In the present invention, the crushing strength of the anion exchange resin is measured as follows.
<Crushing strength measurement method>
(1) Collect hundreds of spherical anion exchange resins that pass through a 850 μm sieve and remain on a 600 μm sieve and store in demineralized water until measurement.
(2) Select at least 60 samples at random and measure the strength with a Chatillon tester or equivalent.
(3) The average value of the intensity for all particles is calculated.

[3] Production method of mixed bed resin and ultrapure water The mixed bed resin of the present invention uses the anion exchange resin of the present invention and an arbitrary cation exchange resin, and is known, for example, in JP-A-2002-102719. It can manufacture by the method of.
In addition, the mixed bed resin using the anion exchange resin of the present invention can produce high-purity ultrapure water with less eluate, for example, by a known method such as JP-A-2002-102719.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded.

[Example 1]
590 g of styrene (industrial grade, manufactured by Idemitsu) and 85 g of divinylbenzene (industrial grade, purity 63 wt%, non-polymerizable impurity content 0.09 wt%, manufactured by Dow) 8 wt% based on the total amount of monomers And nitrogen gas was bubbled through the monomer mixture for 1 hour at 1 L / min to prepare a deoxygenated monomer mixture having an oxygen concentration of 1 mg / L. To this mixture, 1.8 g of dibenzoyl peroxide (purity 75 wt%, wet product, manufactured by NOF Corporation) and 1.4 g of t-butyl peroxybenzoate (purity 99 wt%, manufactured by NOF Corporation) were mixed, and 0.1% The suspension was suspended in 2025 g of an aqueous solution of polyvinyl alcohol (for industrial use, manufactured by Nippon Synthetic Chemical Co., Ltd., grade GH-20). The suspension was stirred at 80 ° C. for 5 hours and then reacted at 120 ° C. for 4 hours to obtain a crosslinked copolymer.
The obtained crosslinked copolymer was subjected to a dissolution test according to the following procedure, and the amount of soluble polystyrene as the soluble compound (I) was quantified.

<Quantification of amount of elution polystyrene>
1) Take 1 part by weight of a crosslinked copolymer in an Erlenmeyer flask.
2) Add 4.5 parts by weight of tetrahydrofuran (grade for high performance liquid chromatography manufactured by Wako Pure Chemical Industries, Ltd.).
3) Hold at 40 ° C. for 5 hours.
4) The resulting tetrahydrofuran supernatant and water are mixed at a ratio of 1: 7 (volume ratio).
5) The turbidity of the obtained solution is measured by the UV method, and the amount of elution polystyrene is determined based on the calibration curve of the tetrahydrofuran solution of the polystyrene sample measured by the same method.

  150 g of the above crosslinked copolymer was put into a round bottom four-necked flask, 525 g of chloromethyl methyl ether (purity 90%, own product) was added, and the copolymer was sufficiently swollen over 8 hours at room temperature. Thereafter, 56 g of zinc chloride (manufactured by Hanwa Kogyo Co., Ltd.) was added as a Friedel-Crafts reaction catalyst, and the reaction was carried out for 8 hours while stirring at a bath temperature of 40 ° C. to obtain a chloromethylated crosslinked copolymer.

  The chloromethylated crosslinked copolymer was batch washed with 3.5 times volume of methanol (manufactured by Nippon Alcohol Sales) and 10 times volume of toluene (manufactured by Wako Pure Chemicals, reagent) for 13 hours, and then 30% by weight trimethylamine aqueous solution ( Wako Pure Chemical Reagent) was added and reacted for 8 hours with stirring at 30 ° C. to obtain an I-type quaternary ammonium-type anion exchange resin (Cl-type).

It was measured using the aforementioned exchange capacity and moisture content of the type I quaternary ammonium type anion-exchange resin [2-1-1] [Measurement method of exchange capacity Q _Cl and water content W _Cl].

  Further, the I-type quaternary ammonium type anion exchange resin obtained above was put in a reaction vessel and stirred at 100 ° C. for 8 hours in a 1N-NaOH (manufactured by Wako Pure Chemical Industries) aqueous solution. Then, the resin is taken out, packed in a column, washed with water, regenerated by passing through an aqueous sodium bicarbonate solution (Wako Pure Chemicals reagent) and an aqueous NaOH (Wako Pure Chemicals reagent) aqueous solution, and an OH-type anion exchange resin. Converted to.

After regeneration, the resin was placed in a beaker and a polystyrene sulfonic acid solution having an average molecular weight of 1 × 10 ⁴ was added with stirring. The amount of sulfonic acid groups per liter of anion exchange resin was 0.2 mmol / L-resin. This slurry was transferred to a column, special grade methanol was passed through at room temperature, and finally washed with ultrapure water to obtain an anion exchange resin for ultrapure water.

The exchange capacity and water content of the OH type anion exchange resin were measured using the [Method for measuring exchange capacity Q _OH and water content W _OH ] described in [2-1-2].

Moreover, about the obtained anion exchange resin, (DELTA) TOC was calculated | required by the above-mentioned (A) ultrapure water flow test.
These results are shown in Table 1.

  In Table 1, the divinylbenzene content in all monomers during the synthesis of the crosslinked copolymer, the haloalkyl group introduction rate during the haloalkylation of the crosslinked copolymer, and the chloro content of the haloalkylated crosslinked copolymer are also shown. did.

The presence or absence of batch washing of the chloromethylated cross-linked copolymer with methanol and toluene, and the amount of the eluting compound (II) removed by this batch washing were examined by the following method. The results are shown in Table 1. It was.
<Quantification of removal amount of eluting compound (II)>
1) Take 1 volume part of toluene washing solution of chloromethylated cross-linked copolymer in a sample bottle.
2) Add 2 parts by volume of methanol (1st grade Wako Pure Chemical Reagent) to 1) and mix.
3) The turbidity of the obtained solution is measured by the UV method, and the removal amount of the eluting compound (II) is determined based on the calibration curve of the toluene solution of the polystyrene sample measured by the same method.
In Table 1, “-” indicates that there is no data.

[Example 2]
An anion exchange resin was produced in the same manner as in Example 1 except that styrene and divinylbenzene were copolymerized so that the divinylbenzene content in all monomers was 10% by weight. It was shown in 1.

[Example 3]
Example 1 except that styrene and divinylbenzene were copolymerized so that the divinylbenzene content in all monomers was 4.5% by weight, and the temperature of the chloromethylation reaction bath was 30 ° C. An anion exchange resin was produced in the same manner, and the measurement results are shown in Table 1.

[Example 4]
An anion exchange resin was produced in the same manner as in Example 1 except that the amount of chloromethylation catalyst was 45 g. Table 1 shows the measurement results. In addition, about this anion exchange resin, the crushing strength measurement of [2-4] mentioned above and the volume increase rate of [2-3] were also measured, and the result was written together in Table 1.

[Example 5]
An anion exchange resin was produced in the same manner as in Example 4 except that the temperature of the reaction bath for chloromethylation was 45 ° C. Table 1 shows the measurement results. In addition, about this anion exchange resin, the crushing strength measurement of the above-mentioned [2-4] was also performed, and the result was written together in Table 1.

[Example 6]
Anion was obtained in the same manner as in Example 1 except that styrene and divinylbenzene were copolymerized so that the divinylbenzene content in all monomers was 4.5% by weight and the amount of chloromethylation catalyst was 45 g. An exchange resin was produced, and the measurement results are shown in Table 1.

[Example 7]
Anion exchange was carried out in the same manner as in Example 1 except that a 390 μm uniform particle size styrene / divinylbenzene crosslinked copolymer was produced with the same charge composition as in Example 1 and the amount of chloromethylation catalyst was 45 g. Resin was manufactured and the measurement results are shown in Table 1. In addition, about this anion exchange resin, the crushing strength measurement of [2-4] mentioned above and the volume increase rate of [2-3] were also measured, and the result was written together in Table 1.

[Comparative Example 1]
Example 1 except that styrene and divinylbenzene were copolymerized so that the divinylbenzene content in all monomers was 4.5% by weight, and the temperature of the chloromethylation reaction bath was 60 ° C. An anion exchange resin was produced in the same manner, and the measurement results are shown in Table 1.

[Comparative Examples 2 and 3]
An anion exchange resin was produced in the same manner as in Comparative Example 1 except that styrene and divinylbenzene were copolymerized so that the divinylbenzene content in each monomer was 8 or 6% by weight, respectively. The measurement results are shown in Table 1.

[Comparative Example 4]
A crosslinked copolymer was obtained in the same manner as in Example 1 except that styrene and divinylbenzene were reacted so that the divinylbenzene content in all monomers was 4.5% by weight.
To 140 parts by weight of the obtained cross-linked copolymer, 490 parts by weight of chloromethyl methyl ether was added to sufficiently swell the cross-linked copolymer. Thereafter, 52 parts by weight of zinc chloride was added as a Friedel-Crafts reaction catalyst, the temperature of the solution was kept at 50 ° C., and the reaction was allowed to proceed for 8 hours with stirring.
Using the obtained chloromethylated cross-linked copolymer, an anion exchange resin was produced in the same manner as in Example 1, and the measurement results are shown in Table 1. In addition, about this anion exchange resin, the crushing strength measurement of the above-mentioned [2-4] was also performed, and the result was written together in Table 1.

[Comparative Example 5]
Example 1 except that styrene and divinylbenzene were copolymerized so that the divinylbenzene content in all monomers was 4.5% by weight, and the temperature of the chloromethylation reaction bath was 50 ° C. An anion exchange resin was produced in the same manner, and the measurement results are shown in Table 1.

[Comparative Example 6]
An anion exchange resin was produced in the same manner as in Comparative Example 5 except that the chloromethylated cross-linked copolymer was not subjected to batch washing with methanol and toluene, and the measurement results are shown in Table 1.

[Reference Example 1]
As Reference Example 1, the water content and exchange capacity of a commercially available OH-type anion exchange resin (trade name: Diaion (registered trademark) SAT20L lot 4L682, manufactured by Mitsubishi Chemical Corporation) and ΔTOC of ultrapure water flow test The data is shown in Table 1.

[Reference Examples 2 to 13]
As Reference Examples 2 to 13, the water content and exchange capacity of commercially available Cl-type anion exchange resins are shown in Table 2.
The value of Diaion (registered trademark: manufactured by Mitsubishi Chemical Corporation) indicates the lower limit of the specifications of the water content and the exchange capacity, respectively. As for Amberlite (registered trademark: manufactured by Rohm and Haas), reference literature (“Ion-exchange resin, its technology and application”, practical edition, Organo Corporation, revised 2nd edition, March 1997) The lower limit of the water content and ion exchange amount described in “Amberlite List (Anion Exchange Resin)” on the page is shown.

FIG. 1 shows the relationship between the moisture content and the exchange capacity of the Cl-type anion exchange resins of Examples, Comparative Examples, and Reference Examples.
FIG. 2 shows the relationship between the moisture content and the exchange capacity of the OH-type anion exchange resins of Examples, Comparative Examples, and Reference Examples.

  Also, the horizontal axis represents the exchange capacity of the OH type anion exchange resin described in Examples and Comparative Examples, and the vertical axis represents ΔTOC in the ultrapure water washing test, and FIG. FIG. 4 shows a plot of ΔTOC in an ultrapure water washing test of an OH-type anion exchange resin prepared using the Cl-type anion exchange resin on the horizontal axis.

As is clear from the comparison of the exchange capacity of the anion exchange resins in Tables 1 and 2 and the moisture content, the anion exchange resin obtained in the present invention is compared with the resin by the conventional method having the same moisture content, Both have a low exchange capacity. Further, as is clear from comparing the values of ΔTOC, the anion exchange resin of the present invention has a low ΔTOC value as compared with the resin obtained by the conventional method. Furthermore, the amount of elution polystyrene in the polymerization stage is lower than that of the conventional crosslinked copolymer.
Further, the volume increase rate when mixed with the cation exchange resin did not exceed 150% before mixing.

3 and 4, it was found that both the exchange capacity of the anion exchange resin and ΔTOC have a positive correlation.
The reason why there is a positive correlation between the exchange capacity and ΔTOC as shown in FIG. 3 and FIG. 4 is that an anion exchange resin having no exchange groups (that is, a cross-linked copolymer of a monovinyl aromatic monomer and a polyvinyl aromatic monomer) (Coupled) does not contain any water-soluble eluate, so ΔTOC may approach zero as much as possible.
Moreover, from FIG. 3, when the exchange capacity of OH type anion exchange resin is 1.10 meq / mL or less, (DELTA) TOC is reduced rather than a conventional product.
Moreover, from FIG. 4, when the exchange capacity when measured with a Cl-type anion exchange resin is 1.38 meq / mL or less, ΔTOC is reduced as compared with the conventional product.

{ΔTOC in ultrapure water flow test}
[Example 8]
An empty column having a diameter of 40 mm and a length of 500 mm was filled with ultrapure water having a resistivity = 18.2 MΩ · cm or more, a water temperature = 25 ° C., and a TOC = 0.5 μg / L under room temperature conditions. Water was passed through at 60 hr ⁻¹ , and the TOC concentration (TOC ₀ ) at the measurement column outlet was measured.
Next, after 500 mL of the anion exchange resin of Example 1 was packed in the measurement column, the ultrapure water was passed through the column at SV = 60 hr ⁻¹ at room temperature, and the TOC concentration at the outlet of the measurement column (TOC ₁ ) Was measured.
ΔTOC was calculated by the following formula. The results are shown in FIG.
ΔTOC = TOC ₁ -TOC ₀
As the TOC measuring device, “A-1000” manufactured by Anatel was used.

[Comparative Example 7]
ΔTOC was calculated in the same manner as in Example 8 except that an anion exchange resin (product name EX-AG) for producing ultrapure water manufactured by Kurita Kogyo Co., Ltd. was used. The results are shown in FIG.
As is clear from FIG. 5, in Example 8, ΔTOC is low from the beginning of water flow, and it is clear that the anion exchange resin obtained in the present invention has lower TOC elution than other anion exchange resins. It is.

Claims (16)

The manufacturing method of the anion exchange resin characterized by including the process of following (a)-(e).
(A) Step of obtaining a crosslinked copolymer by copolymerizing a monovinyl aromatic monomer and a crosslinkable aromatic monomer (b) The content of the eluting compound represented by the following formula (I) The process which makes 400 micrograms or less with respect to 1g of crosslinked copolymers with a crosslinkable aromatic monomer

(In the formula (I), Z represents a hydrogen atom or an alkyl group. L represents a natural number.)
(C) A step of introducing a haloalkyl group of 80 mol% or less with respect to the monovinyl aromatic monomer by haloalkylating a crosslinked copolymer having a content of the eluting compound of 400 μg or less with respect to 1 g of the crosslinked copolymer. (D) A step of removing the eluting compound represented by the following formula (II) from the haloalkylated crosslinked copolymer

(In formula (II), X represents a hydrogen atom, a halogen atom, or an alkyl group which may be substituted with a halogen atom. Y represents a halogen atom. M and n each independently represent a natural number. )
(E) reacting the haloalkylated crosslinked copolymer from which the eluting compound has been removed with an amine compound   An anion exchange resin produced by the method for producing an anion exchange resin according to claim 1. The water content W _Cl (wt%) and the exchange capacity per unit volume Q _Cl (meq / mL-resin) when measured in the Cl form are represented by any of the following formulas (1) to (5). An anion exchange resin characterized by that.
Q _Cl ≦ 1.25 (W _Cl <38) (1)
Q _Cl ≦ 1.36 (provided that 38 ≦ W _Cl <42) (2)
Q _Cl ≦ 1.2 (provided that 42 ≦ W _Cl <48) (3)
Q _Cl ≦ 1.1 (provided that 48 ≦ W _Cl <55) (4)
Q _Cl ≦ 0.8 (however, 55 ≦ W _Cl ) (5) The water content W _Cl (wt%) and the exchange capacity per unit volume Q _Cl (meq / mL-resin) when measured in the Cl form are represented by the following formula (8). Anion exchange resin.
Q _Cl ≦ −0.021 W _Cl +2.28 (8) The water content W _OH (wt%) when measured in the OH form and the exchange capacity Q _OH (meq / mL-resin) per unit volume are expressed by the following formula (6) or (7). Characteristic anion exchange resin.
Q _OH ≦ 1.1 (W _OH <66) (6)
Q _OH ≦ 0.9 (provided that 66 ≦ W _OH ) (7) The water content W _OH (wt%) and the exchange capacity per unit volume Q _OH (meq / mL-resin) when measured in the OH form are represented by the following formula (9). Anion exchange resin.
Q _OH ≦ −0.018 W _OH +2.05 (9)   An anion exchange resin obtained by haloalkylating a cross-linked copolymer obtained by copolymerizing a monovinyl aromatic monomer and a cross-linkable aromatic monomer and then reacting with an amine compound, wherein the monovinyl An anion exchange resin, wherein 80 mol% or less of a haloalkyl group is introduced relative to an aromatic monomer. The anion exchange resin according to claim 7, wherein the content of the eluting compound represented by the following formula (I) in the crosslinked copolymer is 400 μg or less with respect to 1 g of the crosslinked copolymer.

(In the formula (I), Z represents a hydrogen atom or an alkyl group. L represents a natural number.) The anion exchange resin according to any one of claims 2 to 8, wherein ΔTOC in the ultrapure water flow test of (A) below is 0.5 ppb or less.
(A) Ultrapure water flow test (1) An empty measurement column having a diameter of 30 mm and a length of 1000 mm was filled with ultrapure water having a specific resistance of 18 MΩ · cm or more and a water temperature of 20 to 40 ° C. under room temperature conditions. The ultrapure water is passed at SV = 30 hr ⁻¹ , and the TOC concentration (TOC ₀ ) of the measurement column outlet water is measured.
(2) After pouring and filling 500 mL of the anion exchange resin into the measurement column, the ultrapure water was passed through the column at SV = 30 hr ⁻¹ at room temperature, and the TOC concentration of the measurement column outlet water after 20 hours. Measure (TOC ₁ ).
(3) Calculate ΔTOC by the following equation.
ΔTOC (ppb) = TOC ₁ −TOC ₀   The anion exchange resin according to any one of claims 2 to 9, which is a spherical anion exchange resin and has a crushing strength per particle of 7.5 N or more. An anion exchange resin characterized in that ΔTOC in the ultrapure water flow test of (A) below is 0.2 ppb or less.
(A) Ultrapure water flow test (1) An empty measurement column having a diameter of 30 mm and a length of 1000 mm was filled with ultrapure water having a specific resistance of 18 MΩ · cm or more and a water temperature of 20 to 40 ° C. under room temperature conditions. The ultrapure water is passed at SV = 30 hr ⁻¹ , and the TOC concentration (TOC ₀ ) of the measurement column outlet water is measured.
(2) After pouring and filling 500 mL of the anion exchange resin into the measurement column, the ultrapure water was passed through the column at SV = 30 hr ⁻¹ at room temperature, and the TOC concentration of the measurement column outlet water after 20 hours. Measure (TOC ₁ ).
(3) Calculate ΔTOC by the following equation.
ΔTOC (ppb) = TOC ₁ −TOC ₀   A spherical anion exchange resin, wherein the crushing strength per particle is 7.5 N or more.   The anion exchange resin according to any one of claims 2 to 12, wherein the volume increase rate when mixed with an anion exchange resin is 150% or less before mixing.   The anion exchange resin according to any one of claims 2 to 13, which is obtained by bringing a water-soluble polymer containing an anionic dissociative group into contact therewith.   A mixed bed resin formed using the anion exchange resin according to any one of claims 2 to 14.   A method for producing ultrapure water for washing electronic parts and materials, characterized in that the anion exchange resin according to any one of claims 2 to 14 is used.

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