JP2021155675A - Manufacturing method of high purity cationic polymer - Google Patents

Abstract

To provide a manufacturing method of a high purity cationic polymer capable of not only reducing a residual amount of impurities derived from a polymerization initiator such as TMSI and so on but also capable of effectively reducing a residual amount of metal ions such as sodium ions and so on.SOLUTION: A manufacturing method of high purity cationic polymers that comprises: a) a step of polymerizing the acid addition salt of a cationic monomer under the presence of a radical polymerization initiator comprising an additive salt of azobis (amidinoalkane) in an aqueous solvent; b) a step of neutralizing the polymer obtained in step a) with an alkali, and c) a step of removing a neutralized salt generated c) and b) steps, in which after the step b), before the step c), a step of heating within a range of temperature of 40 to 90°C is further added, and, a ratio x:y of a total molar number y of alkali added until the end of the step c) from the start of the step b), relative to a molar number x of the an acid additive salt of the cationic monomer supplied to the step a) is within the range of 1:1.08 to 1:1.5.SELECTED DRAWING: None

Description

The present invention relates to a method for producing a high-purity cationic polymer. More specifically, the present invention relates to a method for producing a high-purity cationic polymer suitable for raw materials for electronic materials, raw materials for pharmaceuticals, etc., which are particularly required to have high purity, and its application.

Cationic polymers represented by allylamine-based (co) polymers are widely used in various fields due to their water solubility. For example, coagulants, sludge dehydrating agents, adhesives, and papermaking agents. It is used as a raw material for various functional materials such as antistatic agents, paints, anchor coating agents, dye fixing agents, and inkjet printing agents.
In the production of a cationic polymer, an acid addition salt of a polymerizable monomer such as monoallylamine hydrochloride, which is a cationic monomer, is usually used as a polymerization initiator (for example, 2,2'-azobis-2-methyl). The acid addition salt of the cationic polymer such as the hydrochloride of the allylamine-based (co) polymer obtained by polymerizing in the presence of an inorganic acid salt such as propionamidine or an organic acid salt) is neutralized with an alkali. , It is subjected to purification means such as dialysis to remove the neutralizing salt produced as a by-product. This makes it possible to produce a free cationic polymer such as a free (substantially free of acid addition salt) allylamine-based (co) polymer.

In order to obtain a higher-purity cationic polymer, various improvements to the above-mentioned production method have been proposed. For example, in the production of an allylamine-based (co) polymer, an inorganic salt that can be removed by ion exchange membrane electrodialysis is added in order to remove a succinimide derivative such as tetramethylsuccinimide (TMSI) derived from a polymerization initiator. It has been proposed to perform electrodialysis (see, for example, Patent Document 1).
In addition, the cationic monomer is polymerized in the presence of a polymerization initiator and hypophosphoric acid or a salt thereof, or the cationic monomer is polymerized in the presence of a polymerization initiator, and then hypophosphoric acid is used. A method has also been proposed in which a polymerization initiator or a modified product derived from the polymerization initiator is converted into a succinimide derivative or the like by adding or a salt thereof and heat-treated, and then removed by filtration (see, for example, Patent Document 2). ..

In applications such as raw materials for electronic materials and raw materials for pharmaceuticals, particularly high-purity cationic polymers are required, and not only the residual amount of impurities derived from polymerization initiators such as TMSI is reduced, but also the residual amount of metal ions is reduced. Is also important. Although the improved method proposed above has a certain effect in reducing impurities derived from the polymerization initiator, it cannot always sufficiently reduce the amount of residual metal ions.

Japanese Unexamined Patent Publication No. 2010-43174 Japanese Unexamined Patent Publication No. 2001-253905

The present invention has been made in view of the above background techniques, and not only can the residual amount of impurities derived from the polymerization initiator such as TMSI be reduced, but also the residual amount of metal ions such as sodium ions can be effectively reduced. An object of the present invention is to provide a method for producing a high-purity cationic polymer capable of producing the same.

As a result of intensive studies to solve the above problems, the present inventors neutralized the polymer obtained by polymerizing an acid addition salt of a cationic monomer with an alkali, and then subjected to dialysis and the like. In the conventional production method for removing the neutralized salt produced as a by-product in the purification step, a heating step is added after the neutralization treatment with alkali, and the ratio of alkali to the acid addition salt of the cationic monomer is adjusted. We have found that both the impurities derived from the initiator and the metal ions contained as impurities can be efficiently reduced by making appropriate adjustments, and have completed the present invention.
That is, the present invention
[1]
a) A step of polymerizing an acid addition salt of a cationic monomer in the presence of a radical polymerization initiator composed of an addition salt of azobis (amidinoalkane) in an aqueous solvent;
b) A step of neutralizing the polymer obtained in step a) with an alkali; and c) a step of removing the neutralized salt generated in step b);
In the method for producing a high-purity cationic polymer having
After the step b) and before the step c), there is further a step of heating in the temperature range of 40 to 90 ° C.
The ratio x: y of the total number of moles y of the alkali added from the start of step b) to the end of step c) with respect to the number x of moles of the acid addition salt of the cationic monomer used in step a) is , Is in the range of 1: 1.08 to 1: 1.5.
The method for producing a high-purity cationic polymer.

（式中、Ｒ^１およびＲ^２は、それぞれ炭素数１〜３のアルキル基を示し、それらはたがいに同一であっても異なっていてもよい。）。
［４］
前記ラジカル重合開始剤が２，２′−アゾビス（２−アミジノプロパン）付加塩である［１］又は［２］に記載の高純度カチオン系重合体の製造方法。
［５］
工程ｃ）における中和塩の除去を電気透析で行なう、［１］から［４］のいずれか一項に記載の高純度カチオン系重合体の製造方法。
［６］
サクシンイミド誘導体の含有量が、１，５００ｐｐｍ以下であり、Ｎａイオン含有量が、１０ｐｐｍ以下である、高純度カチオン系重合体溶液。
［７］
サクシンイミド誘導体の含有量が、１,５００ｐｐｍ以下であり、ＮＨ_４イオン含有量が、１５ｐｐｍ以下である、高純度カチオン系重合体溶液。
［８］
サクシンイミド誘導体の含有量が、１,５００ｐｐｍ以下であり、Ｃｌイオン含有量が、５００ｐｐｍ以下である、高純度カチオン系重合体溶液。
［９］
アリルアミン系（共）重合体溶液である、［６］から［８］のいずれか一項に記載の高純度カチオン系重合体溶液。 In addition, the following [2] to [9] are all preferred embodiments or embodiments of the present invention.
[2]
The method for producing a high-purity cationic polymer according to [1], wherein the acid addition salt of the cationic monomer is a hydrochloride of an allylamine-based monomer.
[3]
The method for producing a high-purity cationic polymer according to [1 or 2], wherein the azobis (amidinoalkane) has a structure represented by the following general formula (I).

(In the formula, R ¹ and R ² each represent an alkyl group having 1 to 3 carbon atoms, and they may be the same or different from each other).
[4]
The method for producing a high-purity cationic polymer according to [1] or [2], wherein the radical polymerization initiator is an addition salt of 2,2'-azobis (2-amidinopropane).
[5]
The method for producing a high-purity cationic polymer according to any one of [1] to [4], wherein the neutralized salt is removed by electrodialysis in step c).
[6]
A high-purity cationic polymer solution having a succinimide derivative content of 1,500 ppm or less and a Na ion content of 10 ppm or less.
[7]
The content of succinimide derivative, or less 1,500 ppm, NH ₄ ion content is 15ppm or less, a high purity cationic polymer solution.
[8]
A high-purity cationic polymer solution having a succinimide derivative content of 1,500 ppm or less and a Cl ion content of 500 ppm or less.
[9]
The high-purity cationic polymer solution according to any one of [6] to [8], which is an allylamine-based (co) polymer solution.

The method for producing a high-purity cationic polymer of the present invention can not only reduce impurities derived from an initiator such as TMSI, but also simultaneously reduce metal ions, which are impurities derived from raw materials, and thus can be used as raw materials for electronic materials. It is particularly preferably used in the production of cationic polymers for applications requiring particularly high-purity cationic polymers such as raw materials for pharmaceuticals and pharmaceuticals. Further, in the method for producing a high-purity cationic polymer of the present invention, the equipment of the conventional method for producing a cationic polymer can be used as it is or by simply adding relatively simple operations such as heating and addition of alkali. Since it can be used with only relatively simple improvements, it is suitable for industrialization and has high practical value in terms of cost and quality stability. Furthermore, since it is not necessary to add special additives or the like, the risk of contamination with other impurities is extremely low.

The method for producing a high-purity cationic polymer of the present invention is
a) A step of polymerizing an acid addition salt of a cationic monomer in the presence of a radical polymerization initiator composed of an addition salt of azobis (amidinoalkane) in an aqueous solvent;
b) A step of neutralizing the polymer obtained in step a) with an alkali; and c) a step of removing the neutralized salt generated in step b);
Have.
Hereinafter, preferred forms of the above steps a) to c) will be described.

Step a)
In the step a) constituting the production method of the present invention, the acid addition salt of the cationic monomer is polymerized in the presence of a radical polymerization initiator composed of an addition salt of azobis (amidinoalkane) in an aqueous solvent.

Here, as the aqueous solvent, water, various solvents having an affinity for water, or a combination thereof may be used, and preferred examples thereof include water, hydrochloric acid, sulfuric acid, phosphoric acid, and the like. Inorganic acids such as polyphosphate or aqueous solutions thereof, organic acids such as formic acid, acetic acid, propionic acid, lactic acid or aqueous solutions thereof, alcohols, dimethylsulfoxide, dimethylformamide, and inorganic acid salts such as zinc chloride, calcium chloride, magnesium chloride. Examples include an aqueous solution. These may be used alone or in combination of two or more.

上記一般式（Ｉ）におけるＲ^１およびＲ^２はそれぞれ炭素数１〜３のアルキル基であり、具体的にはメチル基、エチル基、ｎ−プロピル基、イソプロピル基などを挙げることができる。Ｒ^１およびＲ^２は、たがいに同一でも異なっていてもよい。 As the azobis (amidino alkane) addition salt used in the step a), it is preferable to use the azobis (amidino alkane) addition salt represented by the following general formula (I).

^{R 1} and R ² in the above general formula (I) are alkyl groups having 1 to 3 carbon atoms, respectively, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. R ¹ and R ² may be the same or different from each other.

Specific examples of the azobis (amidinoalkane) represented by the general formula (I) include 2,2'-azobis (2-amidinopropane), 2,2'-azobis (2-amidinobutane), and 2,2'-. Azobis (2-amidinopentane), 2,2'-azobis (2-amidino-3-methylbutane), 3,3'-azobis (3-amidinopentane), 3,3'-azobis (3-amidinohexane), Examples thereof include 3,3'-azobis (3-amidino-4-methylpentane) and 4,4'-azobis (4-amidinoheptane).
In step a), addition salts of these compounds are used as the radical polymerization initiator, and 2,2'-azobis (2-amidinopropane) addition salts are particularly preferable.
Suitable addition salts include inorganic acid addition salts such as hydrochloride, sulfate, phosphate, alkyl sulfate, p-toluene sulfonate, formate, acetate, propionate and other inorganic acid addition salts or organic acids. Additional salts can be mentioned.
In step a), the azobis (amidinoalkane) addition salt may be used alone or in combination of two or more.

The cationic monomer that gives the acid addition salt of the cationic monomer used in step a) is not particularly limited, has cationic properties, and is derived from the addition salt of azobis (amidinoalcan) in an aqueous solvent. A compound that can be polymerized in the presence of the radical polymerization initiator can be appropriately used.
As such a cationic monomer, an allylamine-based monomer is preferable, and for example, monoallylamine, N-methylallylamine, N, N-dimethylallylamine, N-cyclohexylammonium, N, N- (methyl) cyclohexylallylamine. , N, N-dicyclohexylallylamine, diallylamine, N-methyldialylamine, N-benzyldiallylamine and other allylamine addition salts, as well as diallyldimethylammonium chloride, diallyldimethylammonium bromide, diallyldimethylammonium iodide, diallyldimethylmethylsulfate. Ammonium, diallylmethylbenzylammonium chloride, diallylmethylbenzylammonium bromide, diallylmethylbenzylammonium iodide, diallylmethylbenzylammonium methylsulfate, diallyldibenzylammonium chloride, diallyldibenzylammonium bromide, diallyldibenzylammonium iodide, methyl A quaternary ammonium salt of diallylamine such as diallyldibenzylammonium sulfate can be preferably used.
Examples of cationic monomers other than allylamine-based monomers include N, N-dialkylaminoalkyl (meth) acrylates, N, N-dialkylaminoalkyl (meth) acrylamides, and vinylamine.
Examples of the additional salt include hydrochloride, hydrobromide, sulfate, sulfite, phosphate and the like, and among them, hydrochloride is preferable.

Only one type of acid addition salt of these cationic monomers may be used, or two or more types may be used in combination.
Further, only the acid addition salt of the cationic monomer may be polymerized, or may be copolymerized with other monomers.
In the latter case, other monomers include cationic monomers having no acid addition salt, sulfur dioxide, dicarboxylic acid, unsaturated carboxylic acid, unsaturated sulfonic acid and salts thereof. Examples include monomers.
The amount of the other monomers used is not particularly limited, but from the viewpoint of fully exerting the effect of the present invention, the amount of the acid addition salt of the cationic monomer used is the amount of all the monomers used. As a reference, it is preferably 50 mol% or more, and particularly preferably 100 mol% or more.

At the time of polymerization, the addition salt of the above-mentioned cationic monomer is usually used in the form of an isolated crystal, but the above-mentioned monomer or an aqueous solution thereof is mixed with an acid and charged. The additional salt may be produced in the system. Needless to say, when an aqueous acid solution is used as a polymerization medium, a predetermined amount of the cationic monomer and the aqueous acid solution can be mixed and polymerized as they are.

The polymerization temperature in step a) varies depending on the type of cationic monomer used, the type of aqueous solvent, and the like, but is usually in the range of 50 ° C. to reflux temperature, preferably 60 to 100 ° C. The polymerization time depends on the type of cationic monomer used, the polymerization temperature, the amount of the radical polymerization initiator, and the like, and cannot be unconditionally determined, but usually 200 hours or less is sufficient. The concentration of the cationic monomer is preferably high within the range of its solubility, but is usually 30% by weight or more, preferably 50 to 90% by weight.
The degree of polymerization in the step a) is not particularly limited, but is preferably 10 to 2,600, particularly preferably 17 to 900, in view of the intended use.
The preferred degree of polymerization corresponds to approximately 500 to 150,000 in terms of weight average molecular weight, and the particularly preferred degree of polymerization corresponds to approximately 1,000 to 50,000 in terms of weight average molecular weight.

（式中、Ｒ^１およびＲ^２は、上記一般式（Ｉ）について説明したものと同様である。） When a cationic monomer is polymerized in the presence of a radical polymerization initiator composed of an azobis (amidinoalkane) addition salt in step a), most of the radical polymerization initiators can be converted into succinimide derivatives. For example, most of the radical polymerization initiators composed of the addition salt of azobis (amidinoalkane) represented by the above general formula (I) can be converted into the succinimide derivative represented by the following general formula (II).

(In the formula, R ¹ and R ² are the same as those described in the above general formula (I).)

By cooling the reaction solution (cationic polymer aqueous solution), the succinimide derivative crystallizes and precipitates. Therefore, by solid-liquid separation of this precipitate by means such as filtration according to a conventional method, succinimide, which is an impurity, is used. Derivatives can be removed to some extent.
However, since a considerable amount of the succinimide derivative remains in the aqueous solvent, it is difficult to sufficiently remove the succinimide derivative by this alone. Further, since it takes a considerable amount of time to crystallize and precipitate the succinimide derivative, there is a limit to the removal of the succinimide derivative by this method alone from the viewpoint of productivity.
On the other hand, by subjecting the succinimide derivative dissolved without precipitation to, for example, electrodialysis, preferably ion exchange membrane electrodialysis, the succinimide derivative impurities can be removed until the level becomes lower. In the present invention, it is possible to further remove the succinimide derivative impurity in the step c) described later, and as a condition at that time, the cationic single amount to be applied to the specific alkali addition amount (step a) described later. By satisfying the ratio of the number of moles of alkali to the number of moles of acid addition salt in the body), impurities of succinimide derivative can be effectively removed.

Step b)
In the step b) constituting the production method of the present invention, the polymer obtained in the step a) is neutralized with an alkali.
As a result, a free cationic polymer can be produced from the polymer obtained in step a), which is an addition salt of the cationic polymer.
On the other hand, by the neutralization treatment in step b), a neutralized salt is by-produced from the added salt portion and the alkali. The neutralized salt is removed in step c) described later.

The form of the alkali used in step b) is not particularly limited, but the form of an aqueous solvent solution, particularly an aqueous solution, is preferable from the viewpoint of compatibility with the aqueous solvent in step a).
The type of alkali is not particularly limited and may be either an inorganic alkali or an organic alkali, but it is preferably an inorganic alkali from the viewpoint of cost and solubility in an aqueous solvent. For example, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, lithium hydroxide aqueous solution, barium hydroxide aqueous solution, sodium hydrogen carbonate aqueous solution, potassium carbonate aqueous solution, sodium carbonate aqueous solution, ammonia water or a mixture thereof can be mentioned as preferable examples. However, an aqueous solution of sodium hydroxide or an aqueous solution of potassium hydroxide is preferable, and an aqueous solution of sodium hydroxide is particularly preferable.

The temperature in step b) is also not particularly limited, but is usually carried out at 35 to 85 ° C. from the viewpoint of suppressing an excessive temperature rise due to the heat of reaction and suppressing excessive precipitation of the neutralized salt, and is usually performed at 45 to 85 ° C. It is preferably carried out at 75 ° C., more preferably at 50 to 70 ° C. The reaction time in step b) can be appropriately selected depending on the conditions such as the reaction temperature, but is preferably 30 minutes to 100 hours, more preferably 4 to 80 hours, and even more preferably 10 to 50 hours.

Step c)
In step c) constituting the production method of the present invention, the neutralized salt produced in step b) is removed from the polymer solution. Dialysis is preferable as a means for removing the neutralized salt in step c), electrodialysis is particularly preferable as dialysis, and ion exchange membrane electrodialysis is most preferable.

As described above, in step c), not only the neutralizing salt but also impurities derived from the initiator such as TMSI are removed. In the present invention, the heating step is provided between the step b) and the step c), and the acid of the cationic monomer used for the amount of alkali added (step a) up to the step c). By setting the ratio of the number of moles of alkali to the number of moles of the added salt within a specific numerical range, impurities derived from the initiator such as TMSI can be effectively removed.

The temperature at which step c) is performed is not particularly limited, but when electrodialysis is performed, it is usually 5 to 60 ° C, preferably 10 to 45 ° C, and particularly preferably 15 to 35 ° C.
The time for performing step c) is also not particularly limited, but when performing electrodialysis, it is usually 1 to 100 hours, preferably 2 to 80 hours, and particularly preferably 3 to 60 hours.

In the present invention, the total number of moles of alkali added from the start of step b) to the end of step c) with respect to the number of moles x of the acid addition salt of the cationic monomer used in step a). The ratio x: y needs to be in the range of 1: 1.08 to 1: 1.5. The molar ratio x: y is preferably in the range of 1: 1.09 to 1: 1.4, and particularly preferably in the range of 1: 1.1 to 1: 1.3.
When the molar ratio x: y is within the above range, the mechanism by which impurities derived from the initiator such as TMSI are effectively removed is not always clear, but it is realized by adding a predetermined amount of alkali during dialysis. It is presumed that the combination of the acidity of the solution and the heating at a predetermined temperature, which will be described later, has something to do with the fact that impurity ions can be more difficult to pass through the ion exchange membrane and more easily separated. Will be done.

工程ａ）に供されるｘモルのカチオン系単量体の酸付加塩が、すべて重合体に取り込まれれば、上記式左辺の様に、ｘモルのカチオン系単量体の酸付加塩（ここでは、一例としてアリルアミン塩酸塩を示す。）由来の構成単位を有する重合体が得られる。これに同じく左辺に示す様にｙモルのアルカリ（ここでは一例として、ＮａＯＨを示す。）を添加すると、もし全てのアルカリが酸付加塩と反応すれば、上記式右辺に示す様に、ｙモルの遊離のアリルアミン単位と、ｘ−ｙモルのアリルアミン塩酸塩単位とを有する共重合体が得られる。
実際の反応では、必ずしも全てのアルカリが酸付加塩と反応しないので、過剰のアルカリ、すなわちｙ＞ｘとなる量のアルカリを加える場合がある。本発明は、ｘ：ｙのモル比をその様なアルカリ過剰な場合を含む特定の数値範囲に設定し、これを特定の条件下の加温工程と組み合わせることで、ＴＭＳＩ等の重合開始剤由来の不純物の残存量が低減できるだけでなく、ナトリウムイオン等の金属イオンの残存量をも効果的に低減することができる、という新たな知見に基づくものである。

If all the acid addition salts of the x-mol cationic monomer used in the step a) are incorporated into the polymer, as shown on the left side of the above formula, the acid addition salt of the x-mol cationic monomer (here). Then, an allylamine hydrochloride is shown as an example.) A polymer having a constituent unit derived from the above can be obtained. Similarly, when y mol of alkali (here, NaOH is shown as an example) is added as shown on the left side, if all the alkali reacts with the acid addition salt, y mol as shown on the right side of the above formula. A copolymer having xy moles of allylamine hydrochloride units and free allylamine units of is obtained.
In the actual reaction, not all alkalis react with the acid addition salt, so an excess alkali, that is, an amount of alkali such that y> x may be added. The present invention is derived from a polymerization initiator such as TMSI by setting the molar ratio of x: y to a specific numerical range including such an excess of alkali and combining this with a heating step under specific conditions. This is based on a new finding that not only the residual amount of impurities in the above can be reduced, but also the residual amount of metal ions such as sodium ions can be effectively reduced.

In order to achieve the above molar ratio, the required amount of alkali may be added in step b), or in addition to the addition of alkali in step b), prior to step c) and / or step. In c), an alkali may be further added. In any case, the total number of moles of alkali added from the start of step b) to the end of step c) with respect to the number of moles x of the acid addition salt of the cationic monomer used in step a). The effect of the present invention can be realized when the ratio x: y of is in the range of 1: 1.08 to 1: 1.5.

The production method of the present invention has a heating step between the above steps b) and c). In the heating step, the aqueous solution containing the polymer (free polymer) neutralized with alkali in step b) is heated within the temperature range of 40 to 90 ° C. The temperature of the heating step is preferably 50 to 80 ° C, more preferably 55 to 75 ° C.
The time for performing the heating step is also not particularly limited, but is usually 1 to 48 hours, preferably 3 to 42 hours, and particularly preferably 6 to 36 hours.
The mechanism by which impurities derived from the initiator such as TMSI are effectively removed by having the heating step is not always clear, but by heating at a predetermined temperature and adding the above-mentioned predetermined amount of alkali, the mechanism is not always clear. It is presumed that there is some relationship with the fact that impurity ions can be more difficult to pass through the ion exchange membrane and more easily separated.

The high-purity cationic polymer obtained by the production method of the present invention is usually obtained in the form of a solution which is an aqueous solvent solution. The content of the succinimide derivative such as TMSI in the solution is significantly reduced as compared with the prior art, for example, 1,500 ppm or less, preferably 1,200 ppm or less, and particularly preferably 900 ppm or less. Is.
The metal ion content in the solution is also significantly reduced as compared with the prior art, for example, 100 ppm or less, preferably 50 ppm or less, and particularly preferably 30 ppm or less. In particular, the Na ion content is usually 10 ppm or less, preferably 9 ppm or less, and particularly preferably 7 ppm or less.
Also, the NH ₄ ion content is usually 15ppm or less, preferably 10ppm or less, particularly preferably not more than 8 ppm.
Further, the Cl ion content is usually 500 ppm or less, preferably 400 ppm or less, and particularly preferably 300 ppm or less.

Applications The high-purity cationic polymer obtained by the method for producing a high-purity cationic polymer of the present invention has limitations of both prior art, that is, impurities derived from an initiator such as TMSI and metal ions which are impurities derived from a raw material. Since it is significantly reduced beyond the above, it is particularly preferably used in applications requiring particularly high-purity cationic polymers such as raw materials for electronic materials and raw materials for pharmaceuticals. In addition, it can be suitably used in various applications such as paper processing agents, inks, paints, adhesives, display materials, and light-transmitting materials. In these various applications, excellent effects such as improvement of color tone and improvement of storage stability are realized by reducing impurities.

Hereinafter, the present invention will be described in more detail with reference to Examples / Comparative Examples, but the present invention is not limited thereto.

In the following Examples / Comparative Examples, the physical properties / characteristics were evaluated by the following method.
(Weight average molecular weight of polymer)
The weight average molecular weight (Mw) of the polymer was measured by gel permeation chromatography (GPC method) using a Chromaster® 5450 high performance liquid chromatograph manufactured by Hitachi High-Tech Science.
The detector was an RI differential refractive index detector, and the column was a Shodex Asahi pack water-based gel filtration type GS-220HQ (exclusion limit molecular weight 3,000) and GS-620HQ (exclusion limit molecular weight 2 million) connected in series. I used the one. Samples were prepared with eluent to a concentration of 0.5 g / 100 ml and 20 μL was used. A 0.4 mol / L sodium chloride aqueous solution was used as the eluent. The column temperature was 30 ° C. and the flow rate was 1.0 ml / min.
A calibration curve was obtained using polyethylene glycol having a molecular weight of 106, 194, 440, 600, 1470, 4100, 7100, 10300, 12600, 23000 or the like as a standard substance, and the weight average molecular weight (Mw) of the polymer was obtained based on the calibration curve. ) Was asked.

(Polymerization yield of polymer)
It was determined by the peak area ratio in the chart obtained by the GPC method.

(TMSI (Tetramethylsuccinimide) Concentration)
The TMSI content was measured using a Tosoh Corporation L-8020 high performance liquid chromatograph. The detector used was a UV-8020 type ultraviolet-visible detector (wavelength 210 nm), and the column used was a TSKgel α-2500 manufactured by Tosoh Corporation and a TSKgel α guard column connected in series. A 50 mM aqueous sodium phosphate solution was used as the eluent, and the column temperature was 40 ° C. and the flow rate was 1.0 ml / min. As a sample, 20 μl of a treatment solution diluted 10-fold with an eluent was injected.

(Metal ion concentration)
The sodium ion content was measured using a Thermo Fisher Scientific Co., Ltd. ICS-1100 cation chromatograph. An electric conductivity detector was used as a detector, and Thermo Fisher Scientific Co., Ltd. IonPac CG-14 was used as a column, and the column temperature was 30 ° C. A 10 mM methanesulfonic acid aqueous solution manufactured by Kanto Chemical Co., Ltd. was used as an eluent, a flow rate of 1.0 ml / min was used, a CERS500 of 4 mm was used as a suppressor, and a current value of 30 mA was used. As a sample, 25 μl of a treatment solution diluted 100-fold with an eluent was injected.

(Comparative Example 1)
A 2 L separable flask equipped with a thermometer, a stirrer, and a cooling tube was charged with 646.58 g of a 57.88% monoallylamine hydrochloride aqueous solution and 223.75 g of distilled water, and heated to 60 ° C. After stabilizing the internal temperature, 16.84 g of the initiator V-50 (2,2'-azobis (2-methylpropionamidine) dihydrochloride) was added, and the polymerization reaction was carried out for a total of 48 hours. After polymerization, it was cooled with water and left for 48 hours, and then neutralized by adding 691.20 g of a 25% NaOH aqueous solution (molar ratio x: y =).
1: 1.07) After neutralization, demonomerization (45 ° C., 1 hour) with an evaporator was performed. After demonomerization, the concentration was adjusted to 12.7 to 13%, and desalting by electrodialysis (about 3 hours, finished 1 hour after the conductivity was completely lowered) was carried out to obtain a monoallylamine polymer.
The evaluation results are shown in Table 1.

(Comparative Example 2)
A monoallylamine polymer was obtained in the same manner as in Comparative Example 1, except that it was heated at 65 ° C. for 90 hours after neutralization with NaOH and before demonomerization with an evaporator.
The evaluation results are shown in Table 1.

(Example 1)
Except that the heating conditions after neutralization by adding NaOH were changed to 65 ° C. for 48 hours, and 66 g of NaOH was added before electrodialysis to change the molar ratio x: y to 1: 1.20. , A monoallylamine polymer was obtained in the same manner as in Comparative Example 2.
The evaluation results are shown in Table 1.

(Example 2)
The same as in Example 1 except that NaOH was added during electrodialysis (40 minutes, 80 minutes and 120 minutes from the start), resulting in a total molar ratio x: y of 1: 1.18. To obtain a monoallylamine polymer.
The evaluation results are shown in Table 1.

(Comparative Example 3)
A 10 L separable flask equipped with a thermometer, a stirrer, and a cooling tube was charged with 4041.12 g of a 57.88% monoallylamine hydrochloride aqueous solution and 1398.42 g of distilled water, and heated to 60 ° C. After stabilizing the internal temperature, 105.26 g of the initiator V-50 (2,2'-azobis (2-methylpropionamidine) dihydrochloride) was added, and the polymerization reaction was carried out for a total of 72 hours. After polymerization, it is cooled with water and neutralized by adding 4320.00 g of a 25% NaOH aqueous solution (molar ratio x: y = 1: 1.2), and after neutralization, demonomerization by an evaporator (50 ° C., 18 hours) is performed. went. After demonomerization, the concentration was adjusted to 12.6% and desalting by electrodialysis (about 3 hours, finished 1 hour after the conductivity was completely lowered) was performed to obtain a monoallylamine polymer.
The evaluation results are shown in Table 1.

As shown in each example, the TMSI concentration and the TMSI concentration and the molar ratio of the specific acid addition salt to the alkali are combined with the heating step after the neutralization treatment step and before the neutralization salt removal step specified in the present invention. The metal ion concentration could be significantly reduced. Although a slight reduction in TMSI concentration was observed only in the heating step after the neutralization treatment step and before the neutralizing salt removal step as shown in Comparative Example 2 or only in a specific molar ratio as shown in Comparative Example 3. It did not reach the reduction effect of the present invention.

The method for producing a high-purity cationic polymer of the present invention can not only reduce impurities derived from initiators such as TMSI, but also simultaneously add metal ions, which are impurities derived from raw materials, by adding a relatively simple operation. Since it can be reduced, it is particularly preferably used in the production of cationic polymers for applications requiring particularly high-purity cationic polymers, such as raw materials for electronic materials and pharmaceutical raw materials, and is used in the chemical industry, paper manufacturing industry, etc. It has high utility in various fields of industry including the electrical and electronic industry.

Claims (9)

a) A step of polymerizing an acid addition salt of a cationic monomer in the presence of a radical polymerization initiator composed of an addition salt of azobis (amidinoalkane) in an aqueous solvent;
b) A step of neutralizing the polymer obtained in step a) with an alkali; and c) a step of removing the neutralized salt generated in step b);
In the method for producing a high-purity cationic polymer having
After the step b) and before the step c), there is further a step of heating in the temperature range of 40 to 90 ° C.
The ratio x: y of the total number of moles y of the alkali added from the start of step b) to the end of step c) with respect to the number x of moles of the acid addition salt of the cationic monomer used in step a) is , Is in the range of 1: 1.08 to 1: 1.5.
The method for producing the above-mentioned high-purity cationic polymer. The method for producing a high-purity cationic polymer according to claim 1, wherein the acid addition salt of the cationic monomer is a hydrochloride of an allylamine-based monomer. The method for producing a high-purity cationic polymer according to claim 1 or 2, wherein the azobis (amidinoalkane) has a structure represented by the following general formula (I).

(In the formula, R ¹ and R ² each represent an alkyl group having 1 to 3 carbon atoms, and they may be the same or different from each other). The method for producing a high-purity cationic polymer according to claim 1 or 2, wherein the radical polymerization initiator is a 2,2'-azobis (2-amidinopropane) -added salt. The method for producing a high-purity cationic polymer according to any one of claims 1 to 4, wherein the neutralized salt is removed by electrodialysis in step c). A high-purity cationic polymer solution having a succinimide derivative content of 1,500 ppm or less and a Na ion content of 10 ppm or less. The content of succinimide derivative, or less 1,500 ppm, NH ₄ ion content is 15ppm or less, a high purity cationic polymer solution. A high-purity cationic polymer solution having a succinimide derivative content of 1,500 ppm or less and a Cl ion content of 500 ppm or less. The high-purity cationic polymer solution according to any one of claims 6 to 8, which is an allylamine-based (co) polymer solution.