Method for purifying polyvinylamine resin, method for producing polyvinylamine resin, and polyvinylamine resin

Abstract

To provide a method for purifying a polyvinyl amine resin for reducing the amount of TOC elution, a method for producing a polyvinyl amine resin with a reduced amount of TOC elution, and a polyvinyl amine resin with a reduced amount of TOC elution.SOLUTION: A method for purifying a polyvinyl amine resin includes the following steps (1)-(3) in this order: step (1) for applying ions to a polyvinyl amine resin with acid; step (2) for washing the polyvinyl amine resin with water; and step (3) for removing the ions of polyvinyl amine resin with alkali. There is also provided a method for producing a polyvinyl amine resin that includes the method for purifying the polyvinyl amine resin.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for purifying a polyvinylamine resin, a method for producing a polyvinylamine resin, and a polyvinylamine resin. [Background technology]

[0002] Polyvinylamine resins are used in a wide range of applications, including gas adsorbents, anion exchange resins, etc. Polyvinylamine resins are usually obtained by polymerizing a monomer containing N-vinylcarboxylic acid amide and hydrolyzing the resulting polymer.

[0003] As a method for producing a polyvinylamine resin, for example, Patent Document 1 discloses a method for producing a polyvinylamine resin by performing reverse phase suspension polymerization of N-vinylformamide and divinylbenzene in cyclohexane while stirring, and hydrolyzing the obtained polymer. Also, Patent Document 2 discloses a method for producing a polyvinylamine resin by performing suspension polymerization of N-vinylformamide, divinylbenzene, and acrylonitrile in salt water in the presence of a dispersant, and hydrolyzing the obtained polymer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-190235 [Patent Document 2] International Publication No. 2016 / 042846 Summary of the Invention [Problem to be solved by the invention]

[0005] The methods for producing polyvinylamine resin disclosed in Patent Documents 1 and 2 do not include a washing step, and therefore the amount of eluted total organic carbon (TOC) in the obtained polyvinylamine resin is not sufficiently reduced.

[0006] If the amount of TOC eluted from the polyvinylamine resin is large, the TOC will elute from the polyvinylamine resin into the water treated with the polyvinylamine resin, causing the treated water to fail to meet the TOC standard for the intended use. In addition, the TOC components eluted from the polyvinylamine resin are often basic, causing another problem of an increase in the pH of the treated water.

[0007] The present invention has been made in view of such problems, and an object of the present invention is to provide a method for purifying a polyvinylamine resin for reducing the amount of TOC eluted. Another object of the present invention is to provide a method for producing a polyvinylamine resin with a reduced amount of TOC eluted. A further object of the present invention is to provide a polyvinylamine resin with a reduced amount of TOC eluted. [Means for solving the problem]

[0008] As described above, no polyvinylamine resin with a reduced amount of TOC elution has been provided up to now. As a result of extensive investigations, the present inventors have found that performing steps (1) to (3) described below is effective for reducing the amount of TOC eluted, and have thus arrived at the present invention.

[0009] That is, the gist of the present invention is as follows. [1] A method for purifying a polyvinylamine resin, comprising the following steps (1) to (3), in that order: Step (1): A step of loading ions into a polyvinylamine resin using an acid Step (2): Washing the polyvinylamine resin with water Step (3): A step of removing ions from the polyvinylamine resin using an alkali [2] The method for purifying a polyvinylamine resin according to [1], wherein the polyvinylamine resin is a crosslinked resin. [3] The method for purifying a polyvinylamine resin according to [1] or [2], wherein the acid in the step (1) is hydrochloric acid. [4] The method for purifying a polyvinylamine resin according to any one of [1] to [3], wherein the alkali in the step (3) is an aqueous solution of an alkali metal hydroxide. [5] A method for producing a polyvinylamine resin, comprising the method for purifying a polyvinylamine resin according to any one of [1] to [4]. [6] Polyvinylamine resin having an elution amount of total organic carbon of 100 ppm or less. Effect of the Invention

[0010] According to the method for purifying a polyvinylamine resin of the present invention, the amount of TOC eluted from the polyvinylamine resin can be reduced. Also, according to the method for producing a polyvinylamine resin of the present invention, a polyvinylamine resin having a reduced amount of TOC eluted can be obtained. Furthermore, the polyvinylamine resin of the present invention has a reduced amount of TOC eluted. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be described in detail below, but the present invention is not limited to the following embodiments and can be modified and practiced in various ways within the scope of the gist. In this specification, when the expression "~" is used, it is used as an expression including the numerical value or physical property value before and after it. In addition, in this specification, "(meth)acrylic" refers to "acrylic", "methacrylic", or both, and "(meth)acrylate" refers to "acrylate", "methacrylate", or both.

[0012] [Method for purifying polyvinylamine resin] The method for purifying a polyvinylamine resin of the present invention includes the following steps (1) to (3) in this order. Step (1): A step of loading ions into a polyvinylamine resin using an acid Step (2): Washing the polyvinylamine resin with water Step (3): A step of removing ions from the polyvinylamine resin using an alkali

[0013] The TOC elution component from the polyvinylamine resin is thought to be non-crosslinked linear polyvinylamine. In the method for purifying a polyvinylamine resin of the present invention, in step (1), the linear polyvinylamine in the polyvinylamine resin is ionized with an acid to make it more soluble in water, and this linear polyvinylamine can be efficiently removed by washing with water in the next step (2). Furthermore, in the next step (3), the adsorbed ions of the polyvinylamine resin ionized with an acid can be removed, so that it is thought that the elution of TOC from the polyvinylamine resin can be suppressed, and a polyvinylamine resin with a low amount of TOC elution can be obtained.

[0014] (Polyvinylamine resin) The polyvinylamine resin used in step (1) is obtained by polymerizing a monomer containing N-vinyl carboxylic acid amide (hereinafter, sometimes referred to as "raw material monomer") and hydrolyzing the obtained polymer. The polyvinylamine resin is preferably a crosslinked resin because it has excellent mechanical strength, is insoluble and infusible, and is easy to handle.

[0015] Examples of N-vinyl carboxylic acid amides include N-vinyl formamide, N-methyl-N-vinyl formamide, N-vinyl acetamide, N-methyl-N-vinyl acetamide, N-vinyl propionamide, N-methyl-N-vinyl propionamide, N-vinyl butylamide, and N-vinyl isobutylamide. These N-vinyl carboxylic acid amides may be used alone or in combination of two or more. Among these N-vinyl carboxylic acid amides, N-vinyl formamide and N-vinyl acetamide are preferred, and N-vinyl formamide is more preferred, because they have excellent atom efficiency and are easily available and synthesized.

[0016] The raw material monomers for the polyvinylamine resin may contain other monofunctional monomers and polyfunctional monomers in addition to N-vinylcarboxylic acid amide.

[0017] The other monofunctional monomer is not particularly limited as long as it is copolymerizable with N-vinyl carboxylic acid amide, and examples thereof include (meth)acrylonitrile, (meth)acrylamide, N-alkyl (meth)acrylamide, N,N'-dialkyl (meth)acrylamide, N,N'-dialkyl amino alkyl (meth)acrylamide, alkyl (meth)acrylate, hydroxyalkyl (meth)acrylate, dialkyl amino alkyl (meth)acrylate, etc. These other monofunctional monomers may be used alone or in combination of two or more. Among these other monofunctional monomers, (meth)acrylonitrile is preferred, and acrylonitrile is more preferred, because it has excellent copolymerizability with N-vinyl carboxylic acid amide.

[0018] The polyfunctional monomer is not particularly limited as long as it is copolymerizable with N-vinyl carboxylic acid amide, and examples thereof include aromatic polyvinyl compounds such as divinylbenzene, trivinylbenzene, and divinyltoluene; and poly(meth)acrylates such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, glycerol di(meth)acrylate, and trimethylolpropane tri(meth)acrylate. One of these polyfunctional monomers may be used alone, or two or more of them may be used in combination. Among these polyfunctional monomers, aromatic polyvinyl compounds are preferred, and divinylbenzene is more preferred, since they do not decompose such as hydrolyzed, and have excellent resistance under acidic and basic conditions.

[0019] The content of the other monofunctional monomer in the raw material monomer is preferably 1 part by mass to 100 parts by mass, more preferably 10 parts by mass to 40 parts by mass, based on 100 parts by mass of N-vinyl carboxylic acid amide. When the content of the other monofunctional monomer in the raw material monomer is 1 part by mass or more, spherical particles are easily obtained. In addition, when the content of the other monofunctional monomer in the raw material monomer is 100 parts by mass or less, the acid adsorption capacity of the polyvinylamine resin is large.

[0020] The content of the polyfunctional monomer in the raw material monomer is preferably 0.1 to 100 parts by mass, more preferably 1 to 20 parts by mass, relative to 100 parts by mass of N-vinyl carboxylic acid amide. When the content of the polyfunctional monomer in the raw material monomer is 0.1 parts by mass or more, the mechanical strength of the polyvinylamine resin is excellent. Also, when the content of the polyfunctional monomer in the raw material monomer is 100 parts by mass or less, spherical particles are easily obtained.

[0021] A known polymerization method can be used for the polymerization of raw material monomers including N-vinyl carboxylic acid amide, and known additives can be used for additives necessary for polymerization such as a polymerization initiator and a dispersant.

[0022] (Process (1)) Step (1) is a step of loading ions onto a polyvinylamine resin using an acid.

[0023] Examples of the acid include hydrochloric acid, hydrobromic acid, sulfuric acid, and nitric acid. These acids may be used alone or in combination of two or more. Among these acids, monovalent acids are preferred because they have a large degree of swelling of the polyvinylamine resin and excellent cleaning properties, and hydrochloric acid and hydrobromic acid are more preferred, with hydrochloric acid being even more preferred.

[0024] The acid is usually used as an aqueous solution. The concentration of the acid in the aqueous acid solution is preferably 2% by mass to 25% by mass, more preferably 4% by mass to 15% by mass. When the acid concentration is 2% by mass or more, ions can be efficiently loaded. Also, when the acid concentration is 25% by mass or less, the load due to shrinkage of the polyvinylamine resin can be suppressed.

[0025] The amount of the acid used in step (1) is preferably 1 to 10 equivalents, more preferably 3 to 6 equivalents, relative to the acid adsorption capacity of the polyvinylamine resin. When the amount of the acid used is 1 equivalent or more, the washing efficiency of the polyvinylamine resin is excellent. Furthermore, when the amount of the acid used is 10 equivalents or less, the loading time can be shortened. The acid adsorption capacity of a polyvinylamine resin is the amount of acid ions that can be adsorbed by the polyvinylamine resin per unit mass of the polyvinylamine resin, and is determined by titration.

[0026] Examples of the method for loading ions onto a polyvinylamine resin using an acid include a column method in which a polyvinylamine resin is packed in a column and an acid is passed through the column, a batch method in which a polyvinylamine resin and an acid are placed in a container and stirred, etc. Among these methods, the column method is preferred because it has a high efficiency of loading ions onto the polyvinylamine resin relative to the amount of acid used.

[0027] The acid flow rate in the column method is SV1hr -1 ~10hr -1 is preferred, SV3hr -1 ~7hr -1 It is more preferable that the acid passing speed is SV1hr. -1 When the acid passing rate is SV10hr or more, the efficiency of loading ions onto the polyvinylamine resin is excellent. -1 When the amount is equal to or less than this, the operability of passing liquid is excellent.

[0028] The temperature when ions are loaded onto the polyvinylamine resin by the acid is preferably 10° C. to 50° C., and more preferably 20° C. to 30° C. When the temperature is 10° C. or higher, the operability of the load is excellent. Also, when the temperature is 50° C. or lower, deterioration of the polyvinylamine resin due to heat can be avoided.

[0029] (Process (2)) Step (2) is a step of washing the polyvinylamine resin that has been subjected to step (1) with water. The water used for washing is preferably water that does not contain ions, such as desalted water, pure water, or ultrapure water.

[0030] The amount of water used is preferably 20 to 300 times, and more preferably 50 to 180 times, the amount (volume) of polyvinylamine resin. When the amount of water used is 20 times or more, the cleaning effect of polyvinylamine resin is excellent. When the amount of water used is 300 times or less, the cleaning efficiency of polyvinylamine resin is excellent.

[0031] Examples of methods for washing polyvinylamine resin with water include a column method in which a polyvinylamine resin is packed in a column and water is passed through the column, a batch method in which polyvinylamine resin and water are placed in a container and stirred, etc. Among these methods, the column method is preferred because it has excellent washing efficiency for polyvinylamine resin relative to the amount of washing water.

[0032] The water flow rate in the column method is SV1hr. -1 ~10hr -1 is preferred, SV3hr -1 ~7hr -1 It is more preferable that the water permeation rate is SV1hr. -1 When the water permeability is SV10hr or more, the cleaning efficiency of the polyvinylamine resin is excellent. -1 When the amount is equal to or less than this, the operability of passing liquid is excellent.

[0033] The washing time with water in the column method is preferably 1 to 4 days, more preferably 2 to 3 days. When the washing time with water is 1 day or more, the washing effect of the polyvinylamine resin is excellent. Furthermore, when the washing time with water is 4 days or less, the washing efficiency of the polyvinylamine resin is excellent.

[0034] In the column method, the water may be passed continuously or intermittently, i.e., the water may be passed by stopping the water pass for a desired period of time. When the water is passed continuously, the water pass rate may be changed midway. When the water is passed intermittently, the water may be passed intermittently at different water pass rates. In addition, between passes of the water, immersion washing may be performed in which the polyvinylamine resin is left to stand in washing water for a predetermined time.

[0035] The temperature when washing the polyvinylamine resin with water is preferably 10° C. to 50° C., more preferably 20° C. to 30° C. When the temperature is 10° C. or higher, the washing efficiency of the polyvinylamine resin is excellent. Also, when the temperature is 50° C. or lower, deterioration of the polyvinylamine resin due to heat can be avoided.

[0036] (Step (3)) Step (3) is a step of removing adsorbed ions from the polyvinylamine resin that has been subjected to step (2) with an alkali.

[0037] Examples of the alkali include alkali metal hydroxides such as sodium hydroxide, lithium hydroxide, and potassium hydroxide. These alkalis may be used alone or in combination of two or more. Among these alkalis, sodium hydroxide and potassium hydroxide are preferred, and sodium hydroxide is more preferred, because they have excellent solubility in water of carbonates generated when handled in air.

[0038] The alkali is usually used as an aqueous solution. The concentration of the alkali in the aqueous alkali solution is preferably 2% by mass to 40% by mass, more preferably 4% by mass to 15% by mass. When the concentration of the alkali is 2% by mass or more, ions can be efficiently removed. Furthermore, when the concentration of the alkali is 40% by mass or less, the load due to the shrinkage of the polyvinylamine resin can be suppressed.

[0039] The amount of alkali used is preferably 1 to 10 equivalents, more preferably 3 to 6 equivalents, relative to the acid adsorption capacity of the polyvinylamine resin. When the amount of alkali used is 1 equivalent or more, the residual ions can be reduced. Furthermore, when the amount of alkali used is 10 equivalents or less, the loading time can be shortened.

[0040] Examples of the method for removing ions from a polyvinylamine resin using an alkali include a column method in which a polyvinylamine resin is packed in a column and an alkali is passed through the column, and a batch method in which a polyvinylamine resin and an alkali are placed in a container and stirred, etc. Among these methods, the column method is preferred because it has a high efficiency of removing ions from the polyvinylamine resin relative to the amount of alkali used.

[0041] The alkali flow rate in the column method is SV1hr. -1 ~10hr -1 is preferred, SV3hr -1 ~7hr -1 It is more preferable that the alkali passing rate is SV1hr. -1 When the alkali passing rate is SV10hr or more, the efficiency of removing ions from the polyvinylamine resin is excellent. -1 When the amount is equal to or less than this, the operability of passing liquid is excellent.

[0042] The temperature when removing ions from the polyvinylamine resin with an alkali is preferably 10° C. to 50° C., and more preferably 20° C. to 30° C. When the temperature is 10° C. or higher, the operability of removing ions is excellent. Furthermore, when the temperature is 50° C. or lower, deterioration of the polyvinylamine resin due to heat can be avoided.

[0043] (Other processes) The method for purifying a polyvinylamine resin of the present invention may include other steps in addition to steps (1) to (3) as long as the effects of the present invention are not impaired. The other steps may be before step (1), between steps (1) and (2), between steps (2) and (3), or after step (3). The other steps may be single or multiple. For example, after step (3), a finishing step of washing the polyvinylamine resin with water may be included. This finishing step is carried out by washing the polyvinylamine resin with water such as desalted water, pure water, or ultrapure water, as in step (2). The finishing step is usually carried out until the washing water becomes neutral (pH 6 to 8).

[0044] [Method of producing polyvinylamine resin] The method for producing a polyamine resin of the present invention includes the above-mentioned steps (1) to (3) and, if necessary, other steps. The details of steps (1) to (3) and other steps are as described above.

[0045] [Polyvinylamine resin] The polyvinylamine resin of the present invention has a TOC elution amount of 100 ppm (ppm by mass) or less, and preferably has a TOC elution amount of 50 ppm or less.

[0046] In order to reduce the amount of TOC eluted from a polyvinylamine resin to 100 ppm or less, the method for purifying a polyvinylamine resin of the present invention may be used. The amount of TOC eluted from the polyvinylamine resin is measured by the method described in the Examples section below. In the measurement of the amount of TOC elution in the Examples described later, the amount of TOC elution increased with the passage of time as the storage period progressed. However, according to the present invention, the amount of TOC elution can be suppressed to 100 ppm or less, preferably 50 ppm or less, even after a storage period of 14 days.

[0047] The polyvinylamine resin obtained by the method for purifying a polyvinylamine resin of the present invention, the polyvinylamine resin obtained by the method for producing a polyvinylamine resin of the present invention, and the polyvinylamine resin of the present invention have a reduced amount of TOC eluted, and are therefore suitable for water treatment, and are particularly suitable for treating drinking water. EXAMPLES

[0048] The present invention will be described in more detail below using examples. However, the present invention is not limited to the description of the following examples as long as it does not deviate from the gist of the present invention.

[0049] (Method for measuring TOC elution amount) For the polyvinylamine resins obtained in Examples 1 and 2 and Comparative Examples 1 and 2, the amount of TOC eluted (ppm) was measured by the following procedure. 2BV of demineralized water was added to the polyvinylamine resin that had been drained using a centrifuge to make a slurry, and 0.28BV of 2N-HCl aqueous solution was added to this and soaked at 25°C for 1 hour. The polyvinylamine resin slurry was drained using a centrifuge to obtain a partially HCl-modified resin. Next, 10mL of the drained partially HCl-modified resin and 20mL of ultrapure water were added to a 100mL Erlenmeyer flask and shaken at 40°C for 14 hours. After completion, the supernatant was sampled and the TOC was measured using a Shimadzu TOC-L. This test was carried out by storing the drained polyvinylamine resin for 0, 7, and 14 days.

[0050] [Production Example 1] 292 parts by mass of demineralized water, 195 parts by mass of ammonium sulfate, and 5.00 parts by mass of polydiallyldimethylammonium chloride aqueous solution (polymer concentration 18% by mass, weight average molecular weight 500,000) were charged into a separable flask, stirred, and dissolved to form a polymerization bath. 100 parts by mass of N-vinylformamide, 8.97 parts by mass of divinylbenzene, 19.2 parts by mass of ethyl acetate, 19.2 parts by mass of acrylonitrile, and 0.64 parts by mass of 2,2'-azobis(2,4-dimethylvaleronitrile) (trade name "V-65", Fujifilm Wako Pure Chemical Industries, Ltd.) as an azo-based polymerization initiator were mixed to form a monomer solution. The monomer solution and the polymerization bath were mixed and stirred at 100 rpm while replacing the atmosphere in the separable flask with nitrogen. After 30 minutes, the temperature was raised, and polymerization was performed at 40°C for 100 minutes, then at 50°C for 1 hour, and then at 60°C for 30 minutes. After polymerization, the mixture was filtered, washed, and filtered to obtain hydrous polymer spherical particles. 100 parts by mass of the reaction product thus obtained was placed in a separable flask, and 150 parts by mass of a 24% by mass aqueous solution of sodium hydroxide was added, followed by hydrolysis at 90°C for 8 hours with stirring. The mixture was washed and filtered to obtain hydrous polyvinylamine resin spherical particles.

[0051] [Example 1] 200 g (308 mL) of the polyvinylamine resin obtained in Production Example 1 was packed into a glass column, and a 2N HCl aqueous solution (HCl concentration: 7.3% by mass) was added at 25° C. for 5 hours. -1The polyvinylamine resin was converted to HCl by passing 1538 mL (5 BV) (4.3 equivalents relative to the acid adsorption capacity) through the column. The desalted water was then immersed in SV for 5 hours. - The glass column was washed with 1538 mL (5 BV) of HCl to remove excess hydrochloric acid. The HCl-modified polyvinylamine resin was then stored in demineralized water at 25°C for 18 hours while still packed in the glass column. The demineralized water was then washed with SV for 5 hours at 25°C. -1 The washing was then repeated once more. The total time required for washing was 49 hours. Next, a 2N-NaOH aqueous solution (NaOH concentration: 8% by mass) was added at 25°C for 5 hours. -1 The solution was passed through the column in an amount of 1538 mL (5 BV) (4.3 equivalents relative to the acid adsorption capacity) at 100° C. to remove chloride ions from the resin in the column. Then, desalted water was added for 5 hours. -1 The solution was passed through the column at 400° C. until the outlet liquid became neutral, and the polyvinylamine resin was purified.

[0052] [Example 2] The storage time of the HCl-treated polyvinylamine resin was changed from 18 hours to 16 hours, and the condition of passing desalted water through the HCl-treated polyvinylamine resin was changed to SV5hr. -1 9230mL to SV10hr -1 The polyvinylamine resin was purified in the same manner as in Example 1, except that the amount of the reaction mixture was changed to 24,600 mL (80 BV).

[0053] [Comparative Example 1] The polyvinylamine resin obtained in Production Example 1 was used as it was.

[0054] [Comparative Example 2] 250 g (384.6 mL) of the polyvinylamine resin obtained in Production Example 1 was packed in a glass column, and desalted water was added at 25° C. for 5 hours. -1 Then, methanol was passed through the column at 25°C for 5 hours. -1 Then, 1923 mL (5 BV) of desalted water was passed through the column at 25°C for 5 hours. -1The polyvinylamine resin was purified by passing 1923 mL (5 BV) through the column.

[0055] The measurement results of the TOC elution amounts of the polyvinylamine resins obtained in Examples 1 and 2 and Comparative Examples 1 and 2 are shown in Table 1.

[0056] [Table 1]

[0057] As can be seen from Table 1, the polyvinylamine resins obtained in Examples 1 and 2 having steps (1) to (3) had a reduced amount of TOC elution. On the other hand, the polyvinylamine resin obtained in Comparative Example 1, which does not include steps (1) to (3), had a large amount of TOC eluted. The polyvinylamine resin obtained in Comparative Example 2, which was washed with methanol and desalted water, also had a large amount of TOC eluted, and the amount of TOC eluted could not be reduced.

[0058] As described above, the TOC eluted from the polyvinylamine resin is considered to be non-crosslinked linear polyvinylamine. In Examples 1 and 2, linear polyvinylamine is ionized with an acid to make it more soluble in water, which is considered to enable efficient cleaning with water. On the other hand, linear polyvinylamine has low solubility in methanol, and therefore, it is considered that no cleaning effect was obtained in Comparative Example 2. [Industrial Applicability]

[0059] The polyvinylamine resin obtained by the method for purifying a polyvinylamine resin of the present invention, the polyvinylamine resin obtained by the method for producing a polyvinylamine resin of the present invention, and the polyvinylamine resin of the present invention have a reduced amount of TOC eluted, and are therefore suitable for water treatment, and are particularly suitable for treating drinking water.

Claims

1. A method for purifying a polyvinylamine resin, comprising the following steps (1) to (3) in order: the amount of acid used in the step (1) is 1 equivalent to 10 equivalents relative to the acid adsorption capacity of the polyvinylamine resin; The method for purifying a polyvinylamine resin, wherein the alkali in the step (3) is an aqueous solution of an alkali metal hydroxide. Step (1): Loading polyvinylamine resin with ions using an acid Step (2): Washing the polyvinylamine resin with water Step (3): Removing ions from the polyvinylamine resin using an alkali

2. 2. The method for purifying a polyvinylamine resin according to claim 1, wherein the polyvinylamine resin is a crosslinked resin.

3. The method for purifying a polyvinylamine resin according to claim 1 or 2, wherein the acid in step (1) is hydrochloric acid.

4. A method for purifying a polyvinylamine resin described in any one of claims 1 to 3, wherein in the step (2), passing water through a column method and immersion washing in which the polyvinylamine resin is left to stand in water are performed.

5. A method for producing a polyvinylamine resin, comprising the method for purifying a polyvinylamine resin according to any one of claims 1 to 4.

6. The method for producing a polyvinylamine resin according to claim 5, wherein the polyvinylamine resin produced has an elution amount of total organic carbon of 100 ppm or less.

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