JP2014189634A - Amphoteric polymer and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an amphoteric polymer as a highly effective scale inhibitor against calcium carbonate scale and iron hydroxide scale, and to provide a method for producing the same.SOLUTION: The amphoteric polymer comprises, as essential components, a structural unit (a) derived from a cationic group-containing monomer (A), a structural unit (b) derived from a polyalkylene glycol-based monomer (B), and a structural unit (c) derived from a carboxyl group-containing monomer (C). The amphoteric polymer contains, relative to a total 100 mass% of all monomers which constitute the amphoteric polymer, 1 to 98 mass% of the structural unit (a), 1 to 98 mass% of the structural unit (b), and 1 to 98 mass% of the structural unit (c).

Description

The present invention relates to an amphoteric polymer and a method for producing the same.

In a cooling water system, a boiler water system, a seawater desalination apparatus, a pulp dissolving kettle, a black liquor concentration kettle, etc., hardness components and the like contained in water combine with carbonate ions and the like to generate scale. When the scale is deposited on the inner wall, various operational obstacles such as a decrease in thermal efficiency and local corrosion may occur. Therefore, conventionally, a scale inhibitor using sodium polyacrylate or the like is known (for example, Patent Document 1). Patent Document 1 discloses that the inhibitory effect on scale generation of the scale inhibitor is presumed to be mainly caused by a dispersing action.
On the other hand, Patent Document 2 discloses at least one selected from amino group-containing monomers represented by the following formulas (N1), (N2), (N3), and (N4) of 1% by mass to 75% by mass. Containing an amino group having, as an essential constituent unit, a structural unit (n) derived from the monomer (N), and a structural unit (b) derived from 25% by mass to 99% by mass of the carboxyl group-containing monomer (B) A water treatment agent containing a copolymer is disclosed.

In the general formula (N1), R ⁰ represents a hydrogen atom or a CH ₃ group, R ¹ represents a CH ₂ group, a CH ₂ CH ₂ group or a single bond, and R ² and R ³ represent a hydrogen atom or Represents an organic group having 1 to 20 carbon atoms, and at least one of R ² and R ³ represents an aryl group having 6 to 20 carbon atoms, an alkyl group having 4 to 20 carbon atoms, and a hydroxyalkyl group having 1 to 8 carbon atoms. In the general formula (N2), R ⁰ represents a hydrogen atom or a CH ₃ group, R ¹ represents a CH ₂ group, a CH ₂ CH ₂ group or a single bond, and R ² and R ³ represent hydrogen. Represents an atom or an organic group having 1 to 20 carbon atoms, and at least one of R ² and R ³ is an aryl group having 6 to 20 carbon atoms, an alkyl group having 4 to 20 carbon atoms, or a hydroxyalkyl having 1 to 8 carbon atoms. represents a group, in the general formula (N3), ^{R 0} represents a hydrogen atom or a CH ₃ group, ^{R 1} , CH ₂ group, _CH 2 CH ₂ group or a single ^bond, R ^2, R 3, ^{R 4} represents a hydrogen atom or an organic group having 1 to 20 carbon ^atoms, at least R ^2, R 3, ^{R 4} One represents an aryl group having 6 to 20 carbon atoms, an alkyl group having 4 to 20 carbon atoms, or a hydroxyalkyl group having 1 to 8 carbon atoms. In the general formula (N4), R ⁰ represents a hydrogen atom or CH ₃ groups, R ¹ represents a CH ₂ group, a CH ₂ CH ₂ group or a single bond, R ² , R ³ and R ⁴ represent a hydrogen atom or an organic group having 1 to 20 carbon atoms, R ² , R ³ and R ^{4 each} represents an aryl group having 6 to 20 carbon atoms, an alkyl group having 4 to 20 carbon atoms, or a hydroxyalkyl group having 1 to 8 carbon atoms.
Patent Document 1 discloses that the water treatment agent exhibits excellent calcium phosphate scale prevention ability.

JP-A-58-216796 JP 2011-72851 A

As described above, although various polymers have been reported in the past, there is room for improving the scale prevention effect, particularly the calcium carbonate and iron hydroxide scale prevention effects. Therefore, the present invention is preferably used as a scale inhibitor for calcium carbonate scale and iron hydroxide scale due to the better dispersibility of calcium carbonate and iron hydroxide when used in water treatment. It is an object to provide a polymer that can be used.

As a result of intensive studies on various polymers / copolymers in order to achieve the above object, the present inventors have found that a specific amphoteric polymer has excellent dispersibility of calcium carbonate and dispersibility of iron hydroxide. Therefore, it has been found that it can be usefully used as a scale inhibitor for calcium carbonate and iron hydroxide. Based on the above findings, the present invention has been completed.

That is, the present invention relates to a structural unit (a) derived from a cationic group-containing monomer (A) represented by the following general formula (1) and a polyalkylene glycol-based single unit represented by the following general formula (2). An amphoteric polymer essentially comprising a structural unit (b) derived from a monomer (B) and a structural unit (c) derived from a carboxyl group-containing monomer (C),
Structural unit derived from polyalkylene glycol monomer (B) and average added mole number n indicating repeat of alkylene glycol unit contained in structural unit (a) derived from cationic group-containing monomer (A) The average added mole number m indicating the repetition of the alkylene glycol unit contained in (b) is a relationship of m> n,
The amphoteric polymer contains 1 to 98% by mass of the structural unit (a) and 1% of the structural unit (b) with respect to 100% by mass of the total amount of structural units derived from all monomers forming the amphoteric polymer. It is an amphoteric polymer characterized in that it contains ˜98% by mass and contains 1 to 98% by mass of the structural unit (c).

上記一般式（１）中、Ｒ^０は、水素原子又はＣＨ_３基を表す。Ｒ^１は、ＣＨ_２基、ＣＨ_２ＣＨ_２基、ＣＯ基（カルボニル基）又は直接結合を表す。Ｒ^２は、炭素数１〜５の有機基を表す。
Ｒ^３は、窒素原子含有置換基を示し、その他の置換基としては、水素原子又は炭素数１〜６０の３級アミン又は４級アンモニウム塩を示す。また、Ｒ^３には、カウンターアニオンＸ⁻を含む場合がある。Ｚは、同一若しくは異なって、炭素数２〜２０のアルキレン基を表す。ｎは、オキシアルキレン基（−Ｚ−Ｏ−）の平均付加モル数であって、１〜３００の数を表す。

In the general formula (1), R ⁰ represents a hydrogen atom or a CH ₃ group. R ¹ represents a CH ₂ group, a CH ₂ CH ₂ group, a CO group (carbonyl group) or a direct bond. R ² represents an organic group having 1 to 5 carbon atoms.
R ³ represents a nitrogen atom-containing substituent, and the other substituent is a hydrogen atom, a tertiary amine having 1 to 60 carbon atoms, or a quaternary ammonium salt. R ³ may contain a counter anion X ⁻ . Z is the same or different and represents an alkylene group having 2 to 20 carbon atoms. n is the average addition mole number of an oxyalkylene group (—Z—O—) and represents a number of 1 to 300.

上記一般式（２）中、Ｒ^０は、水素原子又はＣＨ_３基を表す。Ｒ¹は、ＣＨ_２基、ＣＨ_２ＣＨ_２基、ＣＯ基（カルボニル基）又は直接結合を表す。Ｚは、同一若しくは異なって、炭素数２〜２０のアルキレン基を表す。ｍは、オキシアルキレン基（−Ｚ−Ｏ−）の平均付加モル数であって、１〜３００の数を表す。Ｙは、水素原子又は炭素数８〜２０の有機基を表す。

In the general formula (2), R ⁰ represents a hydrogen atom or a CH ₃ group. R ¹ represents a CH ₂ group, a CH ₂ CH ₂ group, a CO group (carbonyl group) or a direct bond. Z is the same or different and represents an alkylene group having 2 to 20 carbon atoms. m is an average addition mole number of an oxyalkylene group (—Z—O—) and represents a number of 1 to 300. Y represents a hydrogen atom or an organic group having 8 to 20 carbon atoms.

The present invention also provides an average addition mole number n indicating the repetition of alkylene glycol units contained in the structural unit (a) derived from the cationic group-containing monomer (A) represented by the following general formula (1): The average added mole number m showing the repetition of the alkylene glycol unit contained in the structural unit (b) derived from the polyalkylene glycol monomer (B) represented by the following general formula (2) is m> n Relationship,
A cationic group-containing monomer (A) represented by the following general formula (1), a polyalkylene glycol monomer (B) represented by the following general formula (2), and a carboxyl group-containing monomer ( A process for producing an amphoteric polymer comprising a step of polymerizing (C) with:
In the production method, the monomer (A) is 1 to 98% by mass, the monomer (B) is 1 to 98% by mass, the monomer (C ) Is used in an amount of 1 to 98% by mass.

上記一般式（１）中、Ｒ^０は、水素原子又はＣＨ_３基を表す。Ｒ^１は、ＣＨ_２基、ＣＨ_２ＣＨ_２基、ＣＯ基（カルボニル基）又は直接結合を表す。Ｒ^２は、炭素数１〜５の有機基を表す。
Ｒ^３は、窒素原子含有置換基を示し、その他の置換基としては、水素原子又は炭素数１〜６０の３級アミン又は４級アンモニウム塩を示す。また、Ｒ^３には、カウンターアニオンＸ⁻を含む場合がある。Ｚは、同一若しくは異なって、炭素数２〜２０のアルキレン基を表す。ｎは、オキシアルキレン基（−Ｚ−Ｏ−）の平均付加モル数であって、１〜３００の数を表す。

In the general formula (1), R ⁰ represents a hydrogen atom or a CH ₃ group. R ¹ represents a CH ₂ group, a CH ₂ CH ₂ group, a CO group (carbonyl group) or a direct bond. R ² represents an organic group having 1 to 5 carbon atoms.
R ³ represents a nitrogen atom-containing substituent, and the other substituent is a hydrogen atom, a tertiary amine having 1 to 60 carbon atoms, or a quaternary ammonium salt. R ³ may contain a counter anion X ⁻ . Z is the same or different and represents an alkylene group having 2 to 20 carbon atoms. n is the average addition mole number of an oxyalkylene group (—Z—O—) and represents a number of 1 to 300.

上記一般式（２）中、Ｒ^０は、水素原子又はＣＨ_３基を表す。Ｒ¹は、ＣＨ_２基、ＣＨ_２ＣＨ_２基、ＣＯ基（カルボニル基）又は直接結合を表す。Ｚは、同一若しくは異なって、炭素数２〜２０のアルキレン基を表す。ｍは、オキシアルキレン基（−Ｚ−Ｏ−）の平均付加モル数であって、１〜３００の数を表す。Ｙは、水素原子又は炭素数８〜２０の有機基を表す。

In the general formula (2), R ⁰ represents a hydrogen atom or a CH ₃ group. R ¹ represents a CH ₂ group, a CH ₂ CH ₂ group, a CO group (carbonyl group) or a direct bond. Z is the same or different and represents an alkylene group having 2 to 20 carbon atoms. m is an average addition mole number of an oxyalkylene group (—Z—O—) and represents a number of 1 to 300. Y represents a hydrogen atom or an organic group having 8 to 20 carbon atoms.

The amino group-containing copolymer of the present invention has excellent dispersibility of calcium carbonate and dispersibility of iron hydroxide. Therefore, it can be usefully used as a scale inhibitor for, for example, calcium carbonate and iron hydroxide.

Hereinafter, the present invention will be described in detail.

[Amphoteric polymer of the present invention]
In this specification, the amphoteric polymer refers to a polymer having both a cationic group and an anionic group in one molecule.

<Cationic group-containing monomer (A)>
The amphoteric polymer of the present invention is a polymer essentially comprising the structural unit (a) derived from the cationic group-containing monomer (A) represented by the following general formula (1).

上記一般式（１）中、Ｒ^０は、水素原子又はＣＨ_３基を表す。Ｒ^１は、ＣＨ_２基、ＣＨ_２ＣＨ_２基、ＣＯ基（カルボニル基）又は直接結合を表す。Ｒ^２は、炭素数１〜５の有機基を表す。
Ｒ^３は、窒素原子含有置換基を示し、その他の置換基としては、水素原子又は炭素数１〜６０の３級アミン又は４級アンモニウム塩を示す。また、Ｒ^３には、カウンターアニオンＸ⁻を含む場合がある。Ｚは、同一若しくは異なって、炭素数２〜２０のアルキレン基を表す。ｎは、オキシアルキレン基（−Ｚ−Ｏ−）の平均付加モル数であって、１〜３００の数を表す。

In the general formula (1), R ⁰ represents a hydrogen atom or a CH ₃ group. R ¹ represents a CH ₂ group, a CH ₂ CH ₂ group, a CO group (carbonyl group) or a direct bond. R ² represents an organic group having 1 to 5 carbon atoms.
R ³ represents a nitrogen atom-containing substituent, and the other substituent is a hydrogen atom, a tertiary amine having 1 to 60 carbon atoms, or a quaternary ammonium salt. R ³ may contain a counter anion X ⁻ . Z is the same or different and represents an alkylene group having 2 to 20 carbon atoms. n is the average addition mole number of an oxyalkylene group (—Z—O—) and represents a number of 1 to 300.

In the general formula (1), when R ¹ is a direct bond, H ₂ C═C (R ⁰ ) —R ¹ —O— in the general formula (1) is H ₂ C═C (R ⁰ ) -O-. That is, H ₂ C═C (R ⁰ ) —R ¹ — is an acryl group when R ⁰ is a hydrogen atom and R ¹ is a CO group (carbonyl group), R ⁰ is a methyl group, and R ¹ is a CO group (carbonyl group). Group) is an acrylic group, R ⁰ is a CH ₃ group, R ¹ is a CH ₂ group, a methallyl group, R ⁰ is a CH ₃ group, and R ¹ is a CH ₂ CH ₂ group, an isoprenyl group, R ⁰ Is CH ₃ group, when R ¹ is a direct bond, isopropenyl group, R ⁰ is hydrogen atom, when R ¹ is CH ₂ group, allyl group, R ⁰ is hydrogen atom, R ¹ is CH ₂ CH ₂ group In this case, it is a butenyl group, R ⁰ is a hydrogen atom, and when R ¹ is a direct bond, it is a vinyl group.

The group having a polymerizable carbon-carbon double bond in the cationic group-containing monomer (A), that is, H ₂ C═C (R ⁰ ) —R ¹ — includes an isoprenyl group, a methallyl group, and an allyl group. A vinyl group, a methacryl group, and an acrylic group are preferable. From the viewpoint of enhancing the polymerizability, an isoprenyl group, a methallyl group, an allyl group, and a methacryl group are more preferable, and an isoprenyl group and a methallyl group are particularly preferable.

R ² in the general formula (1) represents an organic group having 1 to 5 carbon atoms, and may have one or a plurality of hydroxyl groups, amino groups, ketone groups, carboxyl groups, and halides. Of these, the case having a hydroxyl group is preferred from the viewpoint of ease of synthesis.
In addition, R ² in the general formula (1) is not particularly limited as to the structure of the organic group having 1 to 5 carbon atoms, but is preferably an alkyl group, an aryl group, or an alkenyl group.
R ² in the general formula (1) preferably has an organic group having 2 to 3 carbon atoms, and more preferably has an organic group having 3 carbon atoms.

Further, a more preferred form of R ² in the general formula (1), having an organic group having 3 carbon atoms, a case where a hydroxyl group in its organic radical. The position of the hydroxyl group is not particularly limited. However, when the organic group having 3 carbon atoms has a hydroxyl group, the group located at the center, such as —CH ₂ —CH (OH) —CH ₂ —, is more suitable for synthesis. It is preferable from the viewpoint of ease.

R ³ in the general formula (1) represents a nitrogen atom-containing substituent. The chemical species bonded to the nitrogen atom may have 1 to 3 hydrogen atoms or organic groups having 1 to 20 carbon atoms. That is, when all of them are hydrogen atoms, it becomes an amino group, and when a combination of a hydrogen atom and an organic group having 1 to 20 carbon atoms is a secondary amine, the organic group having 1 to 20 carbon atoms is the same or different substituent. When two bonds to a nitrogen atom, it becomes a tertiary amine. In addition, the organic group is the same or different substituents having 1 to 20 carbon atoms and three attached to the nitrogen atom, further counter anion X ^- if there is show a quaternary ammonium salt.

R ³ in the general formula (1) represents a nitrogen atom-containing substituent as described above, and the substituent on the nitrogen atom is a hydrogen atom or an organic group having 1 to 20 carbon atoms. The substituent on the nitrogen atom is not particularly limited as long as it is an organic group having 1 to 20 carbon atoms, but is preferably an alkyl group, an aryl group, or an alkenyl group. The alkyl group, aryl group, and alkenyl group may be an unsubstituted group or a group in which one or more of the hydrogen atoms are substituted with another organic group.
Other organic groups in this case include an alkyl group (when the organic group bonded to the nitrogen atom is an alkyl group, the organic group after substitution corresponds to an unsubstituted alkyl group as a whole), an aryl group Alkenyl group, alkoxy group, hydroxyl group, acyl group, ether group, amide group, ester group, ketone group, carboxyl group, carboxyl group salt, sulfonic acid group, sulfonic acid group salt and the like.

The carbon number of the organic groups bonded to the nitrogen atom of R ³ is 1-8, more preferably 1-5, 1-2 is more preferable. If the number of carbon atoms is in the above range, the cationic group-containing monomer (A) can be produced with a high yield, so that the polymerizability of the monomer and the purity of the resulting polymer are improved. Moreover, the dispersibility of the calcium carbonate and the dispersibility of iron hydroxide of the polymer obtained are also improved.
Specifically, alkyl groups such as methyl group, ethyl group, isopropyl group, n-propyl group, n-butyl group, isobutyl group, octyl group, lauryl group, stearyl group, cyclohexyl group, 2-ethylhexyl group; butylene group , An alkenyl group such as an octylene group and a nonylene group; an aryl group such as a phenyl group, a benzyl group, a phenethyl group, a 2,3- or 2,4-xylyl group, a mesityl group, a naphthyl group, or one of these hydrogen atoms A group in which a part is substituted with an alkoxy group, a carboxy ester group, an amino group, an amide group, a hydroxyl group, a carboxyl group, a salt of a carboxyl group, a sulfonic acid group, a salt of a sulfonic acid group, such as a hydroxyethyl group, a hydroxypropyl group, etc. Is mentioned. Among these, a methyl group and an ethyl group are preferable from the viewpoint of improving the dispersibility of calcium carbonate and the dispersibility of iron hydroxide in the obtained polymer.

The organic groups bonded to the nitrogen atom contained in R ³ in the general formula (1) may be bonded to each other to form a cyclic structure. In this case, the cyclic structure formed by the combination of a nitrogen atom and a plurality of organic groups is a ^3- to 7-membered ring, that is, the number of carbon atoms in the organic group contained in R ³ is 2 in that the cyclic structure is stabilized. It is preferably ~ 6.

When R ³ in the general formula (1) is represented by another notation, it represents a tertiary amine: NR ⁴ R ⁵ or a quaternary ammonium salt: NR ⁶ R ⁷ R ⁸ X ⁻ (X ⁻ is Represents a counter anion.) R ^{4 to} R ⁸ are the same or different and each represents a hydrogen atom or an organic group having 1 to 20 carbon atoms.
The organic group having 1 to 20 carbon atoms is not limited as long as it has 1 to 20 carbon atoms as a whole, but is preferably an alkyl group, an aryl group, or an alkenyl group. The alkyl group, aryl group, and alkenyl group may be an unsubstituted group or a group in which one or more of the hydrogen atoms are substituted with another organic group. In this case, as the other organic group, when the organic group represented by R ^{4 to} R ⁸ is an alkyl group, the organic group after substitution corresponds to an unsubstituted alkyl group as a whole. ), Aryl group, alkenyl group, alkoxy group, hydroxyl group, acyl group, ether group, amide group, ester group, ketone group, carboxyl group, carboxyl group salt, sulfonic acid group, sulfonic acid group salt and the like.

R ⁴ the number of carbon atoms of to R ⁸ is 1-8, more preferably 1-5, 1-2 is more preferable. If the number of carbon atoms is in the above range, the cationic group-containing monomer (A) can be produced with a high yield, so that the polymerizability of the monomer and the purity of the resulting polymer are improved. Moreover, the dispersibility of the calcium carbonate and the dispersibility of iron hydroxide of the polymer obtained are also improved.
Specifically, alkyl groups such as methyl group, ethyl group, isopropyl group, n-propyl group, n-butyl group, isobutyl group, octyl group, lauryl group, stearyl group, cyclohexyl group, 2-ethylhexyl group; butylene group , An alkenyl group such as an octylene group and a nonylene group; an aryl group such as a phenyl group, a benzyl group, a phenethyl group, a 2,3- or 2,4-xylyl group, a mesityl group, a naphthyl group, or one of these hydrogen atoms A group in which a part is substituted with an alkoxy group, a carboxy ester group, an amino group, an amide group, a hydroxyl group, a carboxyl group, a salt of a carboxyl group, a sulfonic acid group, a salt of a sulfonic acid group, such as a hydroxyethyl group, a hydroxypropyl group, etc. Is mentioned. Among these, a methyl group and an ethyl group are preferable from the viewpoint of improving the dispersibility of calcium carbonate and the dispersibility of iron hydroxide in the obtained polymer.

R ^{4 to} R ⁵ or R ^{6 to} R ⁸ in the general formula (1) may be bonded to each other to form a cyclic structure. In this case, the cyclic structure formed by the nitrogen atom, R ⁴ and R ⁵ (or R ⁶ and R ⁷ ) is a 3- to 7-membered ring, that is, R ⁴ and R ^{5 in} that the cyclic structure is stabilized. The total number of carbon atoms (or the sum of R ⁶ and R ⁷ ) is preferably 2-6.

In the above general formula (1), Z is the same or different and is an alkylene group having 2 to 20 carbon atoms. From the viewpoint of improving the polymerizability of the cationic group-containing monomer (A), Z is An alkylene group having 2 to 4 carbon atoms is preferable, and an alkylene group having 2 to 3 carbon atoms is more preferable. Specifically, an alkylene group having 2 to 4 carbon atoms such as an ethylene group, a propylene group, or a butylene group is preferable, and an alkylene group having 2 to 3 carbon atoms such as an ethylene group or a propylene group is more preferable. As said alkylene group, 1 type (s) or 2 or more types can be used, but when using 2 or more types, the oxyalkylene group represented by -Z-O- is a random addition, a block addition, an alternating addition, etc. Any of these additional forms may be used.
In the said General formula (1), n is the average addition mole number of an oxyalkylene group (-Z-O-), and represents the number of 1-300. From the viewpoint that the dispersibility of calcium carbonate and dispersibility of iron hydroxide of the polymer are remarkably improved by allowing the anionic group and the cationic group to exist at positions apart from each other in the obtained polymer molecule. n is preferably 4 or more, more preferably 9 or more, and still more preferably 18 or more. Further, from the viewpoint of improving the polymerizability of the cationic group-containing monomer (A), n is preferably 190 or less, more preferably 140 or less, and still more preferably 90 or less.

If the cationic group-containing monomer (A) has a quaternized nitrogen atom, the nitrogen atom vicinity quaternized, counter anion X ^- so that there is. The type of the counter anion X ⁻ is not particularly limited, but is preferably a halogen atom ion or an alkyl sulfate ion. Specific examples of the halogen atom ion include ions such as a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom. Of these, ions of chlorine atom, bromine atom and iodine atom are preferable, and ion of chlorine atom is more preferable. Specific examples of the alkyl sulfate ion include methyl sulfate ion and ethyl sulfate ion. Of these, methyl sulfate ion is preferable.

The amphoteric polymer of the present invention has a structural unit (a) derived from the cationic group-containing monomer (A). The structural unit (a) is a structure in which the carbon-carbon double bond of the cationic group-containing monomer (A) is a single bond, and can be represented by the following general formula (3).

式中、Ｒ^０は、水素原子又はＣＨ_３基を表す。Ｒ^１は、ＣＨ_２基、ＣＨ_２ＣＨ_２基、ＣＯ基（カルボニル基）又は直接結合を表す。Ｒ^２は、炭素数１〜５の有機基を表す。
Ｒ^３は、窒素原子含有置換基を示し、その他の置換基としては、水素原子又は炭素数１〜６０の３級アミン又は４級アンモニウム塩を示す。また、Ｒ^３には、カウンターアニオンＸ⁻を含む場合がある。Ｚは、同一若しくは異なって、炭素数２〜２０のアルキレン基を表す。ｎは、オキシアルキレン基（−Ｚ−Ｏ−）の平均付加モル数であって、１〜３００の数を表す。

In the formula, R ⁰ represents a hydrogen atom or a CH ₃ group. R ¹ represents a CH ₂ group, a CH ₂ CH ₂ group, a CO group (carbonyl group) or a direct bond. R ² represents an organic group having 1 to 5 carbon atoms.
R ³ represents a nitrogen atom-containing substituent, and the other substituent is a hydrogen atom, a tertiary amine having 1 to 60 carbon atoms, or a quaternary ammonium salt. R ³ may contain a counter anion X ⁻ . Z is the same or different and represents an alkylene group having 2 to 20 carbon atoms. n is the average addition mole number of an oxyalkylene group (—Z—O—) and represents a number of 1 to 300.

The amphoteric polymer of the present invention contains “structural unit (a) derived from cationic group-containing monomer (A)” means that the finally obtained polymer is represented by the general formula (3). It is meant to include the structural unit represented. That is, in the “structural unit (a) derived from the cationic group-containing monomer (A)” in the present invention, after synthesizing the cationic group-containing monomer (A), the other unit amount is added. In addition to those introduced into the polymer by copolymerization with the body component, for example, the main chain portion of the amphoteric polymer is first formed by copolymerization, and then the side chain having a specific structure is introduced. In some cases, the forming process extends before and after the polymerization reaction.

The content of the structural unit (a) in the amphoteric polymer of the present invention is the total amount of structural units derived from all monomers forming the amphoteric polymer (structural unit (a), structural unit (b) described later, and 1 mass% or more and 98 mass% or less with respect to 100 mass% (total amount of the structural unit (c) mentioned later). When the content of the structural unit (a) is within the above range, the effect of significantly improving the dispersibility of the calcium carbonate and the dispersibility of iron hydroxide in the polymer can be obtained. The content of the structural unit (a) is preferably 1% by mass or more and 88% by mass or less, more preferably 2% by mass or more and 77% by mass or less, and further preferably 2% by mass or more and 64% by mass. It is as follows.
In addition, the mass ratio (mass%) with respect to the total amount of the structural unit derived from all the monomers of the said structural unit (a), and the mass ratio with respect to the total amount of all the monomers of the said monomer (A) are calculated. In this case, the mass of the counter anion is not taken into consideration (not included).
Moreover, the structural unit (a) possessed by the amphoteric polymer of the present invention may be only one type or two or more types.

Since the structural unit (a) in the amphoteric polymer of the present invention has a particularly high effect of improving the dispersibility of calcium carbonate and the dispersibility of iron hydroxide, the structural unit represented by the general formula (3) is essential. It is preferable that The content of the structural unit represented by the general formula (3) is 1% by mass or more and 98% by mass or less with respect to 100% by mass of the total amount of structural units derived from all monomers forming the amphoteric polymer. It is preferable that

<Method for Producing Cationic Group-Containing Monomer (A)>
The cationic group-containing monomer (A) can also be produced by an applicable known production method, but the cationic group-containing monomer (A) is represented by the general formula (1). When it has a structure, it is preferably produced by the following methods (i) to (iii). According to this method, the cationic group-containing monomer (A) can be produced with high yield.
The production method (i) is a method including a step of esterifying a polyalkylene glycol having a structure in which an alkylene glycol is added to an amine compound and (meth) acrylic acid.
The production method (ii) is a method including a step of adding a polyalkylene glycol having a structure in which an alkylene glycol is added to an amine compound and a glycidyl group of a glycidyl ether having a carbon-carbon double bond.
In the production method (iii), a polyalkylene glycol chain-containing monomer represented by the following general formula (4), an epihalohydrin, and an alkali compound are reacted, and a reaction product obtained in that process is reacted with a tertiary amine salt. The method includes a process.

式中、Ｒ^０は、水素原子又はＣＨ_３基を表す。Ｒ^１は、ＣＨ_２基、ＣＨ_２ＣＨ_２基、ＣＯ基（カルボニル基）又は直接結合を表す。Ｚは、同一若しくは異なって、炭素数２〜２０のアルキレン基を表す。ｎはオキシアルキレン基（−Ｚ−Ｏ−）の平均付加モル数であり、１〜３００の数を表す。
なお、Ｒ^０、Ｒ^１及びＺの好ましい形態は、上記一般式（１）におけるＲ^０、Ｒ^１及びＺの好ましい形態と同様である。

In the formula, R ⁰ represents a hydrogen atom or a CH ₃ group. R ¹ represents a CH ₂ group, a CH ₂ CH ₂ group, a CO group (carbonyl group) or a direct bond. Z is the same or different and represents an alkylene group having 2 to 20 carbon atoms. n is an average addition mole number of an oxyalkylene group (—Z—O—), and represents a number of 1 to 300.
^A preferable embodiment of R 0, ^{R 1} and Z are the same as the preferred form of ^R 0, ^{R 1} and Z in the general formula (1).

<Polyalkylene glycol monomer (B)>
The polyalkylene glycol monomer of the present invention is required to have a specific proportion of the structural unit (b) derived from the polyalkylene glycol monomer (B) represented by the following general formula (2). .

In the general formula (2), R ⁰ represents a hydrogen atom or a CH ₃ group. R represents a CH ₂ group, a CH ₂ CH ₂ group, a CO group (carbonyl group) or a direct bond. Z represents a hydrogen atom or an organic group having 8 to 20 carbon atoms. Z is the same or different and represents an alkylene group having 2 to 20 carbon atoms. m is an average addition mole number of an oxyalkylene group (—Z—O—) and represents a number of 1 to 300.
From the viewpoint that the dispersibility of calcium carbonate and dispersibility of iron hydroxide of the polymer are remarkably improved by allowing the anionic group and the cationic group to exist at positions apart from each other in the obtained polymer molecule. m is preferably 5 or more, more preferably 10 or more, and still more preferably 20 or more. Further, from the viewpoint of improving the polymerizability of the polyalkylene glycol monomer (B), m is preferably 200 or less, more preferably 150 or less, and even more preferably 100 or less.

In the general formula (2), R ¹ represents a CH ₂ group, a CH ₂ CH ₂ group, a CO group (CO group) because the resulting copolymer has a high effect of improving the dispersibility of calcium carbonate and iron hydroxide. A carbonyl group) or a direct bond. In the present specification, the case where R ¹ represents a direct bond means, for example, that it is C—C when represented by C—R—O.

In the general formula (2), Z is a hydrogen atom or an organic group having 8 to 20 carbon atoms as described above, and is most preferably a hydrogen atom.
On the other hand, when the hydrophobicity needs to be improved, an organic group containing other elements such as carbon atoms and nitrogen atoms may be used. In that case, Z is preferably an organic group having 8 to 17 carbon atoms, and more preferably an organic group having 8 to 14 carbon atoms. Y may contain a functional group such as an amino group, an amide group, a hydroxyl group, an alkoxide group, a sulfonic acid group, a carbonyl group, or a carboxyl group. Y may contain an ether bond, a sulfide bond, an ester bond, or an amide bond. The organic group is preferably an alkyl group, an aryl group, or an alkenyl group, since the effect of improving the ability to suppress precipitation of the resulting copolymer is high.

Preferable Y when it is necessary to improve hydrophobicity, specifically, an octyl group, a lauryl group, a stearyl group, a cyclohexyl group, an alkyl group of 2-ethylhexyl group; an alkenyl group such as an octylene group or a nonylene group; a naphthyl group And aryl groups such as nonylphenyl group.

As described above, in the general formula (2), Z represents an alkylene structure having 2 to 30 carbon atoms. Examples of alkylene include ethylene, propylene, and butylene. It may contain a phenylene group or a naphthylene group.
From the viewpoint of easy production of the polymer, 50 mol% or more of the alkylene structure in the general formula (2) is preferably an ethylene structure. More preferably, in the alkylene structure, 80 mol% or more is an ethylene structure, and most preferably 100 mol% is an ethylene structure. Specifically, 100 mol% of the alkylene structure is an ethylene structure. Specifically, for example, when the monomer (B) is a monomer represented by the general formula (2), the monomer (B ) Has a structure represented by the following general formula (6).

In the general formula (6), R ⁰ represents a hydrogen atom or a CH 3 group, R ¹ represents a CH ₂ group, a CH ₂ CH ₂ group, a CO group (carbonyl group) or a direct bond, and m represents an oxy The average number of moles of ethylene group added, which represents a number from 1 to 300. Y represents a hydrogen atom or an organic group having 8 to 20 carbon atoms.

Since the amphoteric polymer of the present invention exhibits stable dispersibility of calcium carbonate and dispersibility of iron hydroxide even under alkaline conditions, the monomer (B) is an ester group or an amide group. It is preferable not to contain.

The structural unit (b) is a monomer (B), that is, in the formula (2), the unsaturated double bond (CH ₂ ═CH—) is a single bond (—CH ₂ —CH—). It becomes.
That is, the structural unit (b) derived from the monomer (B) indicates a structure represented by the following general formula.

In the general formula (7), R ⁰ represents a hydrogen atom or a CH ₃ group. R represents a CH ₂ group, a CH ₂ CH ₂ group or a direct bond. Y represents a hydrogen atom or an organic group having 8 to 20 carbon atoms. Z is the same or different and represents an alkylene group having 2 to 20 carbon atoms. m is an average addition mole number of an oxyalkylene group (—Z—O—) and represents a number of 1 to 300.

By introducing the structural unit (b) into the amphoteric polymer of the present invention, the amphoteric polymer can improve the dispersibility of calcium carbonate and the dispersibility of iron hydroxide.
Further, the monomer (B) can be obtained because it is relatively easy to copolymerize with the monomer (A) and the monomer (C) described later even in a hydrophilic solvent such as water. The dispersibility of calcium carbonate and dispersibility of iron hydroxide of the amphoteric polymer can be significantly improved.

In the amphoteric polymer of the present invention, the structural unit (b) derived from the polyalkylene glycol monomer (B) represented by the general formula (2) is based on 100% by mass of the structure derived from all monomers. It is essential to have a ratio of 1% by mass or more and less than 90% by mass. In the present invention, a monomer refers to a compound having an unsaturated double bond (referring to a carbon-carbon double bond). When the structural unit (b) is within the above range, excellent effects of improving the dispersibility of calcium carbonate and iron hydroxide of the copolymer can be obtained. The proportion of the structural unit (b) with respect to 100% by mass of the structure derived from all monomers is preferably 1% by mass or more and less than 98% by mass, more preferably 2% by mass or more and less than 89% by mass, more preferably It is 3 mass% or more and less than 78 mass%, Most preferably, it is 6 mass% or more and less than 68 mass%. When the amphoteric polymer of the present invention has the structural unit (b) derived from the monomer (B) within the above range, the amphoteric polymer exhibits good water solubility, and the residual polyalkylene glycol monomer is It tends to decrease. Due to the reduction of the residual polyalkylene glycol monomer, the uniformity when the amphoteric polymer of the present invention is stored in an aqueous solution is improved.

<Carboxyl group-containing monomer (C)>
The amphoteric polymer of the present invention is a polymer essentially comprising the structural unit (c) derived from the carboxyl group-containing monomer (C).
The carboxyl group-containing monomer (C) is a monomer that essentially contains 1) an unsaturated double bond and 2) a carboxyl group and / or a salt thereof. Specifically, unsaturated monocarboxylic acids such as unsaturated monocarboxylic acids and salts thereof such as acrylic acid, methacrylic acid, crotonic acid, α-hydroxyacrylic acid, α-hydroxymethylacrylic acid and derivatives thereof. Examples thereof: unsaturated dicarboxylic acids such as itaconic acid, fumaric acid, maleic acid, citraconic acid and 2-methyleneglutaric acid, and unsaturated dicarboxylic acid monomers such as salts thereof.
The unsaturated dicarboxylic acid-based monomer may be any monomer having one unsaturated group and two carboxyl groups in the molecule, but maleic acid, itaconic acid, citraconic acid, fumaric acid, etc. These monovalent metal salts, divalent metal salts, ammonium salts, organic ammonium salts (organic amine salts) and the like, or anhydrides thereof are suitable.

As the carboxyl group-containing monomer (C), among the above-mentioned monomers, acrylic acid, acrylate, maleic acid and maleate are the amphoteric polymers obtained. It is preferable because the effect of improving performance is high, and it is more preferable to make acrylic acid and acrylate essential.

As the salt of the unsaturated monocarboxylic acid and the salt of the unsaturated dicarboxylic acid, metal salts, ammonium salts or organic amine salts are suitable.
Examples of the metal salt include monovalent metal salts of alkali metals such as sodium salt, lithium salt and potassium salt; alkaline earth metal salts such as magnesium salt and calcium salt; salts such as aluminum and iron.
Examples of the organic amine salt include alkanolamine salts such as monoethanolamine salts, diethanolamine salts, and triethanolamine salts; alkylamine salts such as monoethylamine salts, diethylamine salts, and triethylamine salts; ethylenediamine salts, triethylenediamine salts, and the like. Examples include salts of organic amines such as polyamines.
Of these, ammonium salts, sodium salts, and potassium salts are preferable, and sodium salts are more preferable because the resulting copolymer has a high effect of improving the dispersibility of calcium carbonate and iron hydroxide.

In addition to those described above, the carboxyl group-containing monomer (C) is a half ester of an unsaturated dicarboxylic acid and an alcohol having 1 to 22 carbon atoms, and a half of an unsaturated dicarboxylic acid and an amine having 1 to 22 carbon atoms. It may be an amide, a half ester of an unsaturated dicarboxylic acid and a C2-4 glycol, a half amide of maleamic acid and a C2-4 glycol, or the like.

The structural unit (c) derived from the carboxyl group-containing monomer (C) is a form in which the unsaturated double bond of the monomer (C) is a single bond. The amphoteric polymer of the present invention contains “structural unit (c) derived from carboxyl group-containing monomer (C)” means that the finally obtained polymer is unsaturated of monomer (C). It is meant to include structural units in which double bonds are replaced with single bonds.
The amphoteric polymer of the present invention may have only one type of structural unit (c), but may have two or more types of structural units (c).
In the amphoteric polymer, the structural unit (c) is 100% by mass of the total amount of structural units derived from all monomers (the total amount of the structural units (a) and (b) and the structural unit (c) described later). It is essential to have a ratio of 1% by mass or more and 98% by mass or less. If content of a structural unit (c) is in the said range, the remarkable improvement effect of the dispersibility of the calcium carbonate of a polymer and the dispersibility of iron hydroxide will be acquired. The ratio of the structural unit (b) to the total amount of structural units derived from all monomers of 100% by mass is preferably 1% by mass or more and 98% by mass or less, more preferably 10% by mass or more and 97% by mass or less. Yes, more preferably 20% by mass or more and 95% by mass or less, and most preferably 30% by mass or more and 92% by mass or less.
When the amphoteric polymer of the present invention is used as a scale inhibitor, the water solubility of the polymer is improved by containing the structural unit (c) at the specific ratio described above, and the structural unit (a) and the structural unit. It is possible to exhibit the dispersibility of calcium carbonate and iron hydroxide that interact with (b).

In addition, in this invention, when calculating the mass ratio (mass%) with respect to the total amount of the structural unit derived from all the monomers of the structural unit (c) derived from the carboxyl group-containing monomer (C), the corresponding acid conversion It shall be calculated in For example, the mass proportion of the structural unit —CH ₂ —CH (COONa) — derived from sodium acrylate is the mass proportion (mass of the structural unit —CH ₂ —CH (COOH) — derived from acrylic acid, which is the corresponding acid. %). Similarly, when calculating the mass ratio (mass%) of the carboxyl group-containing monomer (C) with respect to the total amount of all monomers, it is calculated in terms of the corresponding acid. For example, the mass ratio of sodium acrylate is calculated as the mass ratio (mass%) of acrylic acid corresponding to the acid.

<Relationship between average addition mole number n and m of oxyalkylene unit>
The amphoteric polymer of the present invention contains, as essential components, the structural unit (a) derived from the cationic group-containing monomer (A) and the structural unit (b) derived from the polyalkylene glycol monomer (B). .
Structural unit derived from polyalkylene glycol monomer (B) and average added mole number n indicating repeat of alkylene glycol unit contained in structural unit (a) derived from cationic group-containing monomer (A) It is essential that the average added mole number m indicating the repetition of the alkylene glycol unit contained in (b) is a relationship of m> n. Structural unit derived from polyalkylene glycol monomer (B) and average added mole number n indicating repeat of alkylene glycol unit contained in structural unit (a) derived from cationic group-containing monomer (A) The average added mole number m indicating the repetition of the alkylene glycol unit contained in (b) is not particularly limited as long as m> n.
If the difference between m and n is 1 to 300 in the relationship of m> n, there is no particular limitation. Preferably, it is 2-100, More preferably, it is 3-70, Most preferably, it is 5-50.
If the relationship between m and n is outside the above range, the amphoteric polymer is not preferred because the calcium carbonate dispersibility and the iron hydroxide dispersibility are reduced.

両性重合体は、該両性重合体を形成する全単量体に由来する構造単位の総量１００質量％に対して、構造単位（ａ）を１〜９８質量％含み、構造単位（ｂ）を１〜９８質量％含み、構造単位（ｃ）を１〜９８質量％含むことを特徴とする両性重合体。

The amphoteric polymer contains 1 to 98% by mass of the structural unit (a) and 1% of the structural unit (b) with respect to 100% by mass of the total amount of structural units derived from all monomers forming the amphoteric polymer. An amphoteric polymer comprising -98% by mass and containing 1-98% by mass of the structural unit (c).

<Other monomers>
The amphoteric polymer of the present invention contains other monomers (D) (other than the cationic group-containing monomer (A), polyalkylene glycol monomer (B) and carboxyl group-containing monomer (C). May have a structural unit (d) derived from the monomer. The amphoteric polymer may have only one type of structural unit (d) or may have two or more types.
The other monomer (D) is not particularly limited as long as it is copolymerizable with the monomers (A), (B), and (C), and can be appropriately selected depending on a desired effect. Specifically, quaternized products of vinyl aromatic monomers having a heterocyclic aromatic hydrocarbon group such as vinyl pyridine and vinyl imidazole, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dimethylaminopropyl acrylate, amino Quaternization of aminoalkyl (meth) acrylates such as ethyl methacrylate, quaternization of allylamines such as diallylamine and diallyldimethylamine, epoxy rings such as (meth) allyl glycidyl ether, isoprenyl glycidyl ether, vinyl glycidyl ether Quaternized monomers obtained by reacting tertiary amine salts, quaternized products of allylamines such as diallylamine and diallyldimethylamine, (meth) allyl glycidyl ether, isoprenyl glycidyl ether, An amino group-containing monomer such as a monomer obtained by reacting a secondary amine with an epoxy ring such as nylglycidyl ether using a known quaternizing agent, other than the above monomer (A) And quaternized amino group (cationic group) -containing monomers.
The secondary amine is preferably a dialkylamine such as dimethylamine, diethylamine, diisopropylamine and di-n-butylamine; an alkanolamine such as diethanolamine and diisopropanolamine; and a cyclic amine such as morpholine and pyrrole. It is done. Known quaternizing agents include alkyl halides and dialkyl sulfuric acid, and specific examples of the tertiary amine salts include trimethylamine hydrochloride and triethylamine hydrochloride. Examples of the salt include hydrochloride and organic acid salt.

As said other monomer (D), in addition to what was mentioned above, vinylsulfonic acid, (meth) allylsulfonic acid, isoprenesulfonic acid, 3-allyloxy-2-hydroxypropanesulfonic acid, acrylamide-2-methylpropane Sulfonic acid group-containing monomers such as sulfonic acid and salts thereof; N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, N-vinyl-N-methylformamide, N-vinyl-N-methylacetamide, N -N-vinyl monomers such as vinyl oxazolidone; Amide monomers such as (meth) acrylamide, N, N-dimethylacrylamide and N-isopropylacrylamide; Hydroxyl-containing monomers such as (meth) allyl alcohol and isoprenol Butyl (meth) acrylate, 2-ethylhexyl (meth) (Meth) acrylic acid alkyl ester monomers such as acrylate and dodecyl (meth) acrylate; hydroxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate, 2-hydroxybutyl (meth) ) Acrylate, 4-hydroxybutyl (meth) acrylate, α-hydroxymethylethyl (meth) acrylate, hydroxypentyl (meth) acrylate, hydroxyneopentyl (meth) acrylate, hydroxyhexyl (meth) acrylate and other (meth) acrylic acid Hydroxyalkyl monomers; vinyl aryl monomers such as styrene, indene and vinylaniline; isobutylene and vinyl acetate.

The structural unit (d) derived from the other monomer (D) is a structural unit in which the unsaturated double bond of the other monomer (D) is replaced with a single bond. The amphoteric polymer of the present invention contains “structural unit (d) derived from other monomer (D)” means that the finally obtained polymer is an unsaturated dimer of monomer (D). It is meant to include structural units in which a heavy bond is replaced with a single bond.
When the amphoteric polymer of the present invention contains a structural unit (d) derived from another monomer (D), which is an optional component, 100% by mass of structural units derived from all monomers (that is, structural unit (a ), (B), (c) and (d) in a total amount of 100% by mass). More preferably, it is 0 mass% or more and 50 mass% or less.
The mass ratio of the structural unit derived from the amino group-containing monomer to the total amount of structural units derived from all monomers and the mass ratio of the amino group-containing monomer to the total amount of all monomers are calculated. In this case, the mass ratio of the corresponding unneutralized amine shall be calculated. For example, when the other monomer (D) is vinylamine hydrochloride, the mass ratio (% by mass) of vinylamine which is the corresponding unneutralized amine is calculated.
When calculating the mass ratio (mass%) of the monomer containing the quaternized amino group or the structural unit derived from it, the mass of the counter anion should not be considered (not included) To do.
When the structural unit (d) is a structural unit derived from an acid group-containing monomer, the mass ratio (% by mass) to the total amount of structural units derived from all monomers is calculated in terms of the corresponding acid. And Moreover, when calculating the mass ratio (mass%) with respect to the total amount of all the monomers of an acid group containing monomer, it shall calculate by corresponding acid conversion.

<Other physical properties of amphoteric polymer>
In the amphoteric polymer of the present invention, the structural unit (a), (b), (c) and, if necessary, the structural unit (d) may be introduced at a specific ratio as described above. Each structural unit may exist in a block shape or a random shape.
The weight average molecular weight of the amphoteric polymer can be set as appropriate and is not particularly limited. Specifically, the weight average molecular weight of the amphoteric polymer is preferably 2,000 to 200,000, more preferably 3,000 to 100,000, and most preferably 4,000 to 60,000. . When the weight average molecular weight is within the above range, the dispersibility of calcium carbonate and the dispersibility of iron hydroxide tend to be improved.
In addition, in this specification, a weight average molecular weight is a measured value by GPC (gel permeation chromatography), and can be measured with the apparatus and measurement conditions described in the Example mentioned later.

The amphoteric polymer of the present invention has a high dispersibility of calcium carbonate, but the dispersibility of calcium carbonate is preferably 0.85 or more. More preferably, it is 0.9 or more, More preferably, it is 0.95 or more.
In addition, the amphoteric polymer of the present invention has a high dispersibility of iron hydroxide, but it is preferable that the dispersibility of iron hydroxide is 0.3 or more. More preferably, it is 0.35 or more, More preferably, it is 0.4 or more.
In addition, the dispersibility of calcium carbonate and the dispersibility of iron hydroxide can be measured in the same manner as in Examples described later.

[Amphoteric polymer composition]
The amphoteric polymer of the present invention may constitute an amphoteric polymer composition together with other components. As said other component, a polymerization initiator residue, a residual monomer, the by-product at the time of superposition | polymerization, a water | moisture content, etc. are mentioned, These 1 type (s) or 2 or more types can be contained. The amphoteric polymer composition preferably contains 1 to 100% by mass of the amphoteric polymer of the present invention relative to 100% by mass of the total amount of the amphoteric polymer composition. One of the preferable forms of the amphoteric polymer composition is a form containing 40 to 60% by mass of the amphoteric polymer of the present invention and 40 to 60% by mass of water.

[Method for producing amphoteric polymer of the present invention]
As a method for producing the amphoteric polymer of the present invention, a known polymerization method or a modified method thereof can be adopted unless otherwise specified. The amphoteric polymer of the present invention includes, for example, a cationic group-containing monomer (A) (monomer (A)) represented by the general formula (1), a polyalkylene glycol monomer (B) ( Monomer (B)) and carboxyl group-containing monomer (C) (monomer (C)) are essential, and other monomer (D) (monomer (D)) is added as necessary. It can manufacture by copolymerizing the monomer component to contain.
Specific polymerization methods include, for example, an oil-in-water emulsion polymerization method, a water-in-oil emulsion polymerization method, a suspension polymerization method, a dispersion polymerization method, a precipitation polymerization method, a solution polymerization method, an aqueous solution polymerization method, a bulk polymerization method, and the like. Can be adopted. Among the polymerization methods exemplified above, it is preferable to employ an aqueous solution polymerization method or an emulsion polymerization method in terms of high safety and reduction in production cost (polymerization cost). In such a production method, the monomer component can be copolymerized using a polymerization initiator.

In the method for producing an amphoteric polymer of the present invention, the composition ratio of each monomer used for polymerization is the total amount of all monomers (monomer (A), (B), (C), (D)). Monomer (A) is 1% by mass or more and 98% by mass or less, monomer (B) is 1% by mass or more and 98% by mass or less, and monomer (B) is 1% by mass with respect to 100% by mass. % Or more and 98% by mass or less.
Preferably, the monomer (A) is 1% by mass or more and 88% by mass or less, the monomer (B) is 2% by mass or more and 89% by mass or less, the monomer (C) is 10% by mass or more, 97 Mass% or less,
More preferably, the monomer (A) is 2% by mass or more and 77% by mass or less, the monomer (B) is 3% by mass or more and 78% by mass or less, the monomer (C) is 20% by mass or more, 95% by mass or less,
Particularly preferably, the monomer (A) is 2% by mass or more and 64% by mass or less, the monomer (B) is 6% by mass or more and 68% by mass or less, the monomer (C) is 30% by mass or more, It is 92 mass% or less.
Moreover, the monomer (D) is 0% by mass or more and 60% by mass with respect to 100% by mass of the total amount of all monomers (monomers (A), (B), (C), (D)). You may include in the following ratios.

<Polymerization initiator>
In the said manufacturing method, a well-known thing can be used as said polymerization initiator. Specifically, hydrogen peroxide; persulfates such as sodium persulfate, potassium persulfate and ammonium persulfate; 2,2′-azobis (2-amidinopropane) hydrochloride, 4,4′-azobis-4-cyanovalerin Azo compounds such as acid, azobisisobutyronitrile, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile); benzoyl peroxide, lauroyl peroxide, peracetic acid, di-t-butyl Organic peroxides such as peroxide and cumene hydroperoxide are preferred. Of these polymerization initiators, hydrogen peroxide, persulfate, and 2,2′-azobis (2-amidinopropane) hydrochloride are preferred, and persulfate and 2,2′-azobis (2-amidinopropane) hydrochloric acid. Most preferred are salts. These polymerization initiators may be used alone or in combination of two or more.

<Chain transfer agent>
In the method for producing an amphoteric polymer of the present invention, a chain transfer agent may be used as a molecular weight regulator of the polymer within a range that does not adversely affect the polymerization, if necessary. Specific examples of the chain transfer agent include mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, octyl thioglycolate, octyl 3-mercaptopropionate, 2- Thiol chain transfer agents such as mercaptoethanesulfonic acid, n-dodecyl mercaptan, octyl mercaptan, butylthioglycolate; halides such as carbon tetrachloride, methylene chloride, bromoform, bromotrichloroethane; Secondary alcohol; phosphorous acid, hypophosphorous acid and salts thereof (sodium hypophosphite, potassium hypophosphite, etc.), sulfurous acid, hydrogen sulfite, dithionic acid, metabisulfite and salts thereof (hydrogen sulfite) Sodium, potassium bisulfite, Sodium dithionite, potassium dithionite, sodium metabisulfite, metabisulfite potassium, etc.) and the like, lower oxides and salts thereof. The said chain transfer agent may be used independently, and 2 or more types may be mixed and used for it.
The use of a chain transfer agent has the advantage that the polymer to be produced can be prevented from becoming higher in molecular weight than necessary, and a low molecular weight amphoteric polymer can be produced efficiently.

In the method for producing an amphoteric polymer of the present invention, it is a preferred form to use sulfurous acid and / or sulfite (hereinafter also referred to as “sulfurous acid (salt)”) as a chain transfer agent. In that case, a polymerization initiator is used in addition to sulfurous acid (salt). Furthermore, you may use a heavy metal ion together as a reaction accelerator mentioned later.
The above sulfurous acid (salt) means sulfurous acid, hydrogen sulfite, or a salt thereof. Among these, a form in which sulfite and / or hydrogen sulfite is a salt is preferable. When sulfite and / or hydrogen sulfite is a salt, a salt of a metal atom, ammonium or organic ammonium is preferred in addition to the above examples.
Examples of the metal atom include monovalent metal atoms of alkali metals such as lithium, sodium and potassium; divalent metal atoms of alkaline earth metals such as calcium and magnesium; trivalent metal atoms such as aluminum and iron Etc. are preferred.
As the organic ammonium (organic amine), alkanolamines such as ethanolamine, diethanolamine, and triethanolamine, and triethylamine are preferable. Further, the sulfite may be an ammonium salt.
Therefore, examples of the sulfite preferably used in the present invention include sodium bisulfite, potassium bisulfite, ammonium bisulfite, sodium sulfite, potassium sulfite, ammonium sulfite and the like, and sodium bisulfite is particularly suitable. The said sulfurous acid (salt) may be used independently, and 2 or more types may be mixed and used for it.

<Reaction accelerator>
In the method for producing an amphoteric polymer of the present invention, a reaction accelerator may be added for the purpose of reducing the amount of initiator used. Examples of the reaction accelerator include heavy metal ions. In the present invention, the heavy metal ion means a metal having a specific gravity of 4 g / cm ³ or more. As said metal ion, iron, cobalt, manganese, chromium, molybdenum, tungsten, copper, silver, gold, lead, platinum, iridium, osmium, palladium, rhodium, ruthenium etc. are preferable, for example. These heavy metals can be used alone or in combination of two or more. Among these, iron is more preferable. The valence of the heavy metal ion is not particularly limited. For example, when iron is used as the heavy metal, the iron ion in the initiator may be Fe ²⁺ or Fe ³⁺ , and both of them may be used. It may be included.
Although the said heavy metal ion will not be specifically limited if it is contained as a form of ion, Since it is excellent in handleability, it is suitable to use the solution formed by melt | dissolving a heavy metal compound. The heavy metal compound used in that case should just contain the heavy metal ion desired to contain in an initiator, and can be determined according to the initiator to be used. When iron is used as the heavy metal ion, the mole salt (Fe (NH ₄ ) ₂ (SO ₄ ) ₂ · 6H ₂ O), ferrous sulfate · 7 hydrate, ferrous chloride, ferric chloride, etc. It is preferable to use a heavy metal compound or the like. Moreover, when using manganese as a heavy metal ion, manganese chloride etc. can be used suitably. Since these are all water-soluble compounds, they can be used in the form of an aqueous solution and have excellent handleability. The solvent of the solution formed by dissolving the heavy metal compound is not limited to water, and does not interfere with the polymerization reaction in the production of the amphoteric polymer of the present invention, and dissolves the heavy metal compound. Anything is acceptable.

The method for adding the heavy metal ions is not particularly limited, but it is preferably added before the monomer addition is completed, and it is particularly preferable to initially charge the entire amount. Further, the amount used is preferably 100 ppm or less, more preferably 70 ppm or less, still more preferably 50 ppm or less, and particularly preferably 30 ppm or less, based on the total amount of the reaction solution. If it exceeds 100 ppm, the effect of the addition is not observed, and the resulting amphoteric polymer is highly deteriorated in coloration, which is not preferable.
The content of the heavy metal ions is preferably 0.1 to 10 ppm with respect to the total mass of the polymerization reaction solution at the completion of the polymerization reaction. If the content of heavy metal ions is less than 0.1 ppm, the effect of heavy metal ions may not be sufficiently exhibited. On the other hand, if the content of heavy metal ions exceeds 10 ppm, the color tone of the resulting polymer may be deteriorated. Moreover, when there is much content of heavy metal ion, when using the polymer which is a product as a water treatment agent, there exists a possibility of becoming a cause of coloring stain | pollution | contamination.
The time when the polymerization reaction is completed means the time when the polymerization reaction is substantially completed in the polymerization reaction solution and a desired polymer is obtained. For example, when the polymer polymerized in the polymerization reaction solution is neutralized with an acid component, the content of heavy metal ions is calculated based on the total mass of the polymerization reaction solution after neutralization. When two or more kinds of heavy metal ions are included, the total amount of heavy metal ions may be in the above range.

In the method for producing an amphoteric polymer of the present invention, in the polymerization, a decomposition catalyst for the polymerization initiator or a reducing compound may be added to the reaction system in addition to the above-described compounds.
Examples of the decomposition catalyst for the polymerization initiator include metal halides such as lithium chloride and lithium bromide; metal oxides such as titanium oxide and silicon dioxide; hydrochloric acid, hydrobromic acid, perchloric acid, sulfuric acid, nitric acid and the like. Metal salts of inorganic acids; Carboxylic acids such as formic acid, acetic acid, propionic acid, lactic acid, isolacic acid, benzoic acid, their esters and their metal salts; heterocyclic amines such as pyridine, indole, imidazole, carbazole and their derivatives Can be mentioned. These decomposition catalysts may be used alone or in combination of two or more.
Examples of the reducing compound include organic metal compounds such as ferrocene; iron naphthenate, copper naphthenate, nickel naphthenate, cobalt naphthenate, manganese naphthenate, and the like, such as iron, copper, nickel, cobalt, and manganese. Inorganic compounds capable of generating metal ions; boron trifluoride ether adducts, potassium permanganate, perchloric acid and other inorganic compounds; sulfur dioxide, sulfite, sulfate, bisulfite, thiosulfate, sulfoxide, Sulfur-containing compounds such as benzenesulfinic acid and its substitutes, and homologues of cyclic sulfinic acid such as para-toluenesulfinic acid; octyl mercaptan, dodecyl mercaptan, mercaptoethanol, α-mercaptopropionic acid, thioglycolic acid, thiopropionic acid, α -Sodium thiopropionate sulfopropyl ester Mercapto compounds such as stealth and α-thiopropionic acid sodium sulfoethyl ester; nitrogen-containing compounds such as hydrazine, β-hydroxyethylhydrazine and hydroxylamine; formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, isovaleraldehyde Aldehydes such as ascorbic acid and the like. These reducing compounds may also be used alone or in combination of two or more. Further, a reducing compound such as a mercapto compound may be added as a chain transfer agent.

The combination of the chain transfer agent, the initiator, and the reaction accelerator is not particularly limited, and can be appropriately selected from the above examples. For example, combinations of chain transfer agent, initiator and reaction accelerator include sodium bisulfite / hydrogen peroxide, sodium bisulfite / sodium persulfate, sodium bisulfite / Fe (ion), sodium bisulfite / hydrogen peroxide / Forms such as Fe (ion), sodium bisulfite / sodium persulfate / Fe (ion), sodium bisulfite / sodium persulfate / hydrogen peroxide, sodium bisulfite / oxygen / Fe (ion) are preferable. More preferred are sodium persulfate / hydrogen peroxide, sodium persulfate / hydrogen peroxide / Fe (ion), sodium bisulfite / sodium persulfate, sodium bisulfite / sodium persulfate / Fe (ion), and most preferred. Are sodium bisulfite / sodium persulfate / Fe (ion) and sodium persulfate / hydrogen peroxide / Fe (ion).

<Amount of polymerization initiator used>
The amount of the polymerization initiator used is not particularly limited as long as it is an amount capable of initiating copolymerization of monomers, but all monomer components (monomer (A), (B), (C) and (D) It is preferable that it is 15 g or less with respect to 1 mol of the total amount. More preferably, it is 1-12g.
When hydrogen peroxide is used as an initiator, the amount of hydrogen peroxide added is preferably 1.0 to 10.0 g with respect to 1 mol of the total amount of all monomer components, and 2.0 to 8 More preferably, it is 0.0 g. When the amount of hydrogen peroxide added is less than 1.0 g, the polymerization average molecular weight of the resulting copolymer tends to increase. On the other hand, when the addition amount exceeds 10.0 g, an effect sufficient to meet the increase in the addition amount cannot be obtained, and further, the remaining hydrogen peroxide amount is adversely affected.
When persulfate is used as an initiator, the amount of persulfate added is preferably 1.0 to 10.0 g, based on 1 mol of the total amount of all monomer components, and 2.0 to 8 More preferably, it is 0.0 g. If the amount of persulfate added is less than the above range, the molecular weight of the resulting copolymer tends to increase. On the other hand, when the addition amount is larger than the above range, an effect corresponding to the increase in the addition amount cannot be obtained, and further, the purity of the resulting copolymer is adversely affected.
When hydrogen peroxide and persulfate are used together as an initiator, the addition ratio of hydrogen peroxide and persulfate is such that the weight ratio of persulfate to hydrogen peroxide is 0.1 to 5.0. Preferably, it is 0.2-2.0. If the weight ratio of persulfate is less than 0.1, the weight average molecular weight of the resulting copolymer tends to be high. On the other hand, if the weight ratio of the persulfate exceeds 5.0, the effect of decreasing the molecular weight due to the addition of the persulfate cannot be obtained enough to meet the increase in the amount added, and the persulfate is wasted in the polymerization reaction system. Will be consumed.

As a method for adding hydrogen peroxide, the amount to be added by dripping substantially continuously is preferably 85% by weight or more of the necessary predetermined amount, more preferably 90% by weight or more, and 100 Most preferably, the weight percent, ie the whole amount, is added dropwise. When hydrogen peroxide is continuously dropped, the dropping speed may be changed.

When hydrogen peroxide is dropped under the appropriate reaction conditions (temperature, pressure, pH, etc.) described later, it is delayed after the start of dropping of the monomer (excluding the initially charged monomer). It is preferable to start. Specifically, preferably after 1 minute or more has elapsed after the start of dropping of the cationic group-containing monomer (A), more preferably after 3 minutes or more, still more preferably after 5 minutes or more, most preferably 10 minutes. The dripping of hydrogen peroxide is started after the lapse of the above. By delaying the start of the dropwise addition of hydrogen peroxide, it is possible to smooth the initial polymerization start and narrow the molecular weight distribution.
The time for delaying the start of dropwise addition of hydrogen peroxide is preferably within 60 minutes, more preferably within 30 minutes after the start of dropping of the monomer.
It is possible to start the dropping of hydrogen peroxide simultaneously with the dropping of the monomer, or to charge hydrogen peroxide in advance before dropping of the monomer. Is preferably 10% or less. More preferably, it is 7% or less, More preferably, it is 5% or less, Most preferably, it is 3% or less.
If more than 10% of the required amount of hydrogen peroxide is added before the start of the dropwise addition of the monomer, for example, when a persulfate is used in combination, the ratio of the concentration of hydrogen peroxide to the persulfate increases, and polymerization is May stop. On the other hand, if it starts later than 60 minutes from the start of the dropping of the monomer, the chain transfer reaction due to hydrogen peroxide does not occur, so the molecular weight at the initial stage of polymerization increases.

Further, the dropping of hydrogen peroxide is preferably terminated simultaneously with the end of dropping of the monomer when the reaction is performed under suitable reaction conditions (temperature, pressure, pH, etc.) described later. Moreover, it is more preferable to complete | finish 10 minutes or more earlier than monomer dropping completion time, and it is especially preferable to complete | finish 30 minutes or more early. In addition, even if it complete | finishes later than the dripping completion time of a monomer, it does not have a bad influence in a polymerization system especially. However, since the added hydrogen peroxide is not completely decomposed by the end of the polymerization, unreacted hydrogen peroxide cannot be obtained and is wasted. Further, it is not preferable that a large amount of hydrogen peroxide remains because it may adversely affect the thermal stability of the obtained polymer.

The method for adding the persulfate is not particularly limited, but considering the decomposability and the like, it is preferable that the amount added by dripping continuously is 50% by weight or more of the required predetermined amount. . More preferably, it is 80 weight% or more, and it is most preferable that 100 weight%, ie, the whole quantity is dripped. When the persulfate is continuously dropped, the dropping speed may be changed.
Although the dropping time is not particularly limited, in the case of performing the reaction under the preferable reaction conditions (temperature, pressure, pH, etc.) described later, since persulfate is a relatively quick initiator, It is preferable to continue dropping until the dropping end time. Moreover, it is more preferable to complete | finish dripping within 30 minutes after completion | finish of monomer dripping, and it is especially preferable to complete dripping within 5 to 20 minutes after monomer dripping. Thereby, the residual amount of the monomer in the produced polymer can be remarkably reduced.
Note that even if the addition of these initiators is completed before the completion of the monomer addition, there is no particular adverse effect on the polymerization, and it starts according to the residual amount of monomer in the obtained copolymer. What is necessary is just to set the dripping completion time of an agent.
For initiators that are relatively quick to decompose, such as the persulfate, the preferred range for the dropping end time has been described, but the dropping start time is not limited in any way and may be set as appropriate. For example, the start of dropping of the initiator may be started before the start of dropping of the monomer. When two or more kinds of initiators are used in combination, the start of dropping of one initiator is started and a certain time has elapsed. You may start dripping another initiator after or after dripping is complete | finished. In either case, the initiator dropping start time may be appropriately set according to the decomposition rate of the initiator and the reactivity of the monomer.

The concentration of the initiator solution when the polymerization initiator is added dropwise is not particularly limited, but is preferably 5 to 60% by weight, particularly preferably 10 to 50% by weight. If the concentration of the initiator is less than 5% by weight, the monomer concentration during the polymerization will be very low as a result. The remaining amount of the body becomes very large. Further, the efficiency and productivity of transportation and the like are lowered, which is not preferable from the economical aspect. On the other hand, if it exceeds 60% by weight, there is a problem in terms of safety and ease of dripping.

The addition amount of the chain transfer agent is not limited as long as the monomers (A), (B), (C) and (D) are polymerized satisfactorily, but preferably the monomers (A), (B ), (C) and (D) with respect to 1 mol of the total amount of all monomer components, it is 1 to 20 g, more preferably 2 to 15 g. If it is less than 1 g, the molecular weight may not be controlled. On the other hand, if it exceeds 20 g, a large amount of impurities may be produced, and the pure polymer content may be reduced. In particular, when sulfite is used, surplus sulfite is decomposed in the reaction system, and sulfurous acid gas may be generated. Furthermore, there is a risk that it may be economically disadvantageous.

As a combination of the initiator and the chain transfer agent, it is most preferable to use one or more persulfates and sulfites. In this case, the mixing ratio of persulfate and sulfite is not particularly limited, but it is preferable to use 0.05 to 5 parts by mass of sulfite with respect to 1 part by mass of persulfate. The lower limit of the amount of sulfite is more preferably 0.1 parts by mass, and most preferably 1 part by mass with respect to 1 part by mass of persulfate. Moreover, as for the upper limit of the amount of sulfites, it is more preferable that it is 4 mass parts with respect to 1 mass part of persulfate, Most preferably, it is 3 mass parts. If the sulfite is less than 0.5 parts by mass with respect to 1 part by mass of the persulfate, the total amount of initiator required may be increased when the molecular weight is lowered. There is a risk that the reaction will increase and impurities will increase.

The total amount of the chain transfer agent, initiator, and reaction accelerator used is 1 mol of the total amount of all monomer components composed of the monomers (A), (B), (C), and (D). 2 to 20 g. By setting it as such a range, the amphoteric polymer of this invention can be produced efficiently, and the molecular weight distribution of an amphoteric polymer can be made into a desired thing. More preferably, it is 4-18g, More preferably, it is 6-15g.

<Polymerization solvent>
In the method for producing an amphoteric polymer of the present invention, the monomers (A), (B), (C) and (D) are copolymerized by the monomers (A), (B), (C) and ( It is preferable to carry out using a solvent which can dissolve D), and it is preferable to use water in 50% by mass or more of the solvent used. Depending on the application, the mixing of the organic solvent may be severely restricted, but by using water in 50% by mass or more of the solvent used, the amount of the organic solvent used for the polymerization can be suppressed, so that after the completion of the polymerization There is an advantage that the organic solvent can be easily distilled off.
Examples of the solvent that can be used by mixing with water include lower alcohols such as methanol, ethanol and isopropyl alcohol; lower ketones such as acetone, methyl ethyl ketone and diethyl ketone; ethers such as dimethyl ether and dioxane; amides such as dimethylformaldehyde Kind. These solvents may be used alone or in the form of a mixture of two or more.
From the viewpoint described above, the amount of water is preferably 80% by mass or more, and most preferably 100% by mass, that is, only water is used as a solvent, with respect to 100% by mass of the total amount of solvent used. . In the case of adding an organic solvent, one or more solvents selected from the group consisting of water and lower alcohols having 1 to 4 carbon atoms from the viewpoint of the solubility of the monomer component and the resulting copolymer. Is preferably used.

As usage-amount of solvents, such as water, 40-200 mass% is preferable with respect to 100 mass% of total amounts of all the monomer components. More preferably, it is 45 mass% or more, More preferably, it is 50 mass% or more. Moreover, More preferably, it is 180 mass% or less, More preferably, it is 150 mass% or less. If the amount of the solvent used is less than 40% by mass, the resulting copolymer may have a high molecular weight. If it exceeds 200% by mass, the concentration of the obtained copolymer will be low, and solvent removal is required. There is a risk. The solvent may be partly or wholly charged in the reaction vessel in the initial stage of polymerization, but a part of the solvent may be added (dropped) into the reaction system during the polymerization reaction, or the monomer. Components, initiators, and the like may be added (dropped) into the reaction system during the polymerization reaction together with these components in a form in which the components and initiator are dissolved in advance.

In the above production method, as a method for adding the monomer component, the polymerization initiator and the chain transfer agent to the reaction vessel, a continuous charging method such as dropping or divided charging can be applied. In addition, each may be introduced alone into the reaction vessel, or may be mixed in advance with other components, a solvent, or the like.
As a specific addition method, a method in which all of the monomer components are charged into a reaction vessel and copolymerization is performed by adding a polymerization initiator into the reaction vessel; a portion of the monomer components are charged into the reaction vessel. A method of carrying out copolymerization by adding a polymerization initiator and the remaining monomer component continuously or stepwise (preferably continuously) into a reaction vessel; charging a polymerization solvent into the reaction vessel; A method of adding the total amount of the monomer component and the polymerization initiator; Among these methods, since the molecular weight distribution of the obtained copolymer can be narrowed (sharpened) and the dispersibility of dirt and the ability to prevent recontamination can be improved, a polymerization initiator and a monomer It is preferable to carry out the copolymerization by a method in which the components are successively dropped into the reaction vessel. Such polymerization can be carried out either batchwise or continuously.

<Polymerization conditions>
In the above production method, the polymerization conditions such as the polymerization temperature are appropriately determined depending on the polymerization method used, the solvent, the polymerization initiator, etc. The polymerization temperature is preferably 0 ° C. or higher, and 150 ° C. or lower. Preferably there is. More preferably, it is 40 degreeC or more, More preferably, it is 60 degreeC or more, Most preferably, it is 70 degreeC or more. Moreover, More preferably, it is 120 degrees C or less, More preferably, it is 110 degrees C or less.
In particular, when sulfurous acid (salt) is used, the polymerization temperature is preferably 60 ° C to 95 ° C. More preferably, it is 70 degreeC-95 degreeC, More preferably, it is 70 degreeC-90 degreeC. If it is less than 60 degreeC, there exists a possibility that the impurity derived from a sulfurous acid (salt) may produce | generate in large quantities. On the other hand, when it exceeds 95 ° C., toxic sulfurous acid gas may be released.
The polymerization temperature does not necessarily need to be kept almost constant in the polymerization reaction. For example, the polymerization is started from room temperature, the temperature is raised to a set temperature with an appropriate temperature increase time or rate, and then the set temperature is increased. You may make it hold | maintain and you may carry out temperature fluctuation (temperature rise or temperature fall) with time during a polymerization reaction according to dripping methods, such as a monomer component and an initiator.

The polymerization time is not particularly limited, but is preferably 30 to 420 minutes, more preferably 45 to 390 minutes, still more preferably 60 to 360 minutes, and most preferably 90 to 300 minutes. In the present invention, “polymerization time” represents the time during which a monomer is added, that is, the time from the start of addition of the monomer to the end unless otherwise specified.

The pressure in the reaction system in the polymerization method may be any of normal pressure (atmospheric pressure), reduced pressure, and increased pressure. However, from the viewpoint of appropriately controlling the molecular weight of the resulting copolymer, It is preferable to carry out under pressure or under pressure while sealing the reaction system. Moreover, it is preferable to carry out under a normal pressure (atmospheric pressure) in the point which does not require equipment, such as a pressurization apparatus, a pressure reduction apparatus, a pressure-resistant reaction container, and piping.
The atmosphere in the reaction system may be an air atmosphere, but is preferably an inert atmosphere. For example, the inside of the system is preferably replaced with an inert gas such as nitrogen before the start of polymerization.

The pH during the polymerization in the polymerization method is not particularly limited. When bisulfite is used as the chain transfer agent, it is preferably carried out under acidic conditions.

[Use of amphoteric polymer and amphoteric polymer composition of the present invention]
The amphoteric polymer (or amphoteric polymer composition) of the present invention comprises a coagulant, a flocculant, printing ink, adhesive, soil conditioner (modifier), flame retardant, skin care agent, hair care agent, shampoo, hair spray, Additives for soaps and cosmetics, anion exchange resins, dye mordants and auxiliaries for fibers and photographic films, pigment spreaders in papermaking, paper strength enhancers, emulsifiers, preservatives, fabric and paper softeners, lubricants It can be used as an additive, water treatment agent, fiber treatment agent, dispersant, scale inhibitor (scale inhibitor), metal ion sealant, thickener, various binders, emulsifiers and the like.

<Water treatment agent>
The amphoteric polymer (or amphoteric polymer composition) of the present invention can be used as a water treatment agent. For the water treatment agent, polymerized phosphates, phosphonates, anticorrosives, slime control agents, and chelating agents may be used as other compounding agents as necessary.
The water treatment agent is useful for scale prevention in a cooling water circulation system, a boiler water circulation system, a seawater desalination apparatus, a pulp digester, a black liquor concentration tank, and the like. Further, any appropriate water-soluble polymer may be included as long as it does not affect the performance and effects.

<Fiber treatment agent>
The amphoteric polymer (or amphoteric polymer composition) of the present invention can also be used as a fiber treatment agent. The fiber treatment agent includes at least one selected from the group consisting of a dye, a peroxide and a surfactant, and the amphoteric polymer (or amphoteric polymer composition) of the present invention.
The content of the amphoteric polymer of the present invention in the fiber treatment agent is preferably 1 to 100% by weight, more preferably 5 to 100% by weight, based on the entire fiber treatment agent. Further, any appropriate water-soluble polymer may be included as long as the performance and effects are not affected.
Below, the compounding example of a fiber processing agent is shown. This fiber treatment agent can be used in the steps of refining, dyeing, bleaching and soaping in fiber treatment. Examples of dyeing agents, peroxides, and surfactants include those usually used for fiber treatment agents.
The blending ratio of the amphoteric polymer of the present invention and at least one selected from the group consisting of a dye, a peroxide and a surfactant is, for example, for improving the whiteness, color unevenness, and dyeing tempering of the fiber. In the amount of pure fiber treatment agent, 0.1 to 100 parts by weight of at least one selected from the group consisting of a dye, a peroxide and a surfactant is used with respect to 1 part by weight of the polymer of the present invention. It is preferable to use the composition mix | blended in this ratio as a fiber processing agent.
Arbitrary appropriate fiber can be employ | adopted as a fiber which can use the said fiber processing agent. Examples thereof include cellulosic fibers such as cotton and hemp, chemical fibers such as nylon and polyester, animal fibers such as wool and silk, semi-synthetic fibers such as human silk, and woven fabrics and blended products thereof.
When the fiber treatment agent is applied to the refining process, it is preferable to blend the polymer of the present invention with an alkali agent and a surfactant. When applied to the bleaching step, it is preferable to blend the polymer of the present invention, a peroxide, and a silicic acid-based agent such as sodium silicate as a decomposition inhibitor for the alkaline bleaching agent.

<Inorganic pigment dispersant>
The amphoteric polymer (or amphoteric polymer composition) of the present invention can also be used as an inorganic pigment dispersant. If necessary, the inorganic pigment dispersant may contain condensed phosphoric acid and a salt thereof, phosphonic acid and a salt thereof, and polyvinyl alcohol as another compounding agent.
The content of the amphoteric polymer of the present invention in the inorganic pigment dispersant is preferably 5 to 100% by weight with respect to the whole inorganic pigment dispersant. Further, any appropriate water-soluble polymer may be included as long as it does not affect the performance and effect.
The inorganic pigment dispersant can exhibit good performance as a dispersant for heavy or light calcium carbonate or clay inorganic pigment used in paper coating. For example, by adding a small amount of an inorganic pigment dispersant to an inorganic pigment and dispersing it in water, high concentration calcium carbonate having low viscosity and high fluidity and good aging stability of their performance. High concentration inorganic pigment slurries such as slurries can be produced.
When the inorganic pigment dispersant is used as a dispersant for an inorganic pigment, the amount of the inorganic pigment dispersant used is preferably 0.05 to 2.0 parts by weight with respect to 100 parts by weight of the inorganic pigment. When the amount of the inorganic pigment dispersant used is within the above range, a sufficient dispersion effect can be obtained, and an effect commensurate with the addition amount can be obtained, which can be economically advantageous.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples. Unless otherwise specified, “part” means “part by mass” and “%” means “% by mass”.
The cationic group-containing monomer and the isoprenol ethylene oxide adduct were quantified by liquid chromatography. Moreover, the weight average molecular weight, calcium carbonate dispersibility, and iron hydroxide dispersibility of the polymer were measured according to the following methods.

<Method for quantifying cationic group-containing monomer and isoprenol ethylene oxide adduct>
The quantitative determination of the cationic group-containing monomer and the ethylene oxide adduct of isoprenol was performed by high-speed chromatography under the following conditions.
Column: manufactured by Shiseido Co., Ltd. CAPCELL PAK C8 DD 4.6 mmΦ × 250 mm 5 μm
Temperature: 40.0 ° C
Eluent: 10 mM Na phosphate (pH 6.8) / acetonitrile = 55/45 vol% (volume ratio)
Flow rate: 0.1 ml / min
Detector: RI, UV (detection wavelength 210 nm).

<Quantification of carboxyl group-containing monomers>
Apparatus: HLC8320 manufactured by Tosoh Corporation
Detector: UV (214 nm)
Column: TSKgel guardcolumn α, α-M, α-2500 manufactured by Tosoh Corporation
Column temperature: 40 ° C
Flow rate: 0.5 ml / min.
Eluent: 0.1N sodium acetate / acetonitrile = 3/1 (mass ratio).

<Measurement conditions of weight average molecular weight>
Apparatus: HLC8320 manufactured by Tosoh Corporation
Detector: RI
Column: TSKgel guardcolumn α, α-M, α-2500 manufactured by Tosoh Corporation
Column temperature: 40 ° C
Flow rate: 0.5 ml / min.
Calibration curve: POLYETHYLENGLYCOL STANDARD made by GL Sciences Inc.
Eluent: 0.1N sodium acetate / acetonitrile = 3/1 (mass ratio).

<Measurement of solid content>
In an oven heated to 130 ° C. in a nitrogen atmosphere, the polymer of the present invention (1.0 g of the polymer composition of the present invention plus 1.0 g of water) was allowed to stand for 1 hour for drying treatment. From the weight change before and after drying, the solid content (%) and the volatile component (%) were calculated.

<Calcium carbonate dispersibility>
Pure water was added to 67.56 g of glycine, 52.6 g of sodium chloride, and 2.4 g of sodium hydroxide to obtain 600 g (this is referred to as buffer (1). 3268 g was added, and pure water was further added to make 1000 g (this is referred to as buffer (2)) 36 g of buffer (2) was added to 4 g of 0.1% by weight aqueous solution of the copolymer to be measured, and the dispersion was stirred. After 0.6 g of calcium carbonate (manufactured by Kanto Chemical) was put into a test tube (IWAKI GLASS, diameter 18 mm, height 180 mm), 30 g of the above dispersion was added and sealed. After the test tube was allowed to stand for 20 hours, 5 cc of the supernatant was taken and the absorbance was measured with a UV spectrometer (wavelength 380 nm). It shows high calcium carbonate dispersibility.

<Iron hydroxide dispersibility>
Pure water was added to 67.56 g of glycine, 52.6 g of sodium chloride, and 2.4 g of sodium hydroxide to obtain 600 g (this is referred to as buffer (1). 3268 g was added, and pure water was further added to make 1000 g (this is referred to as buffer (2)) 36 g of buffer (2) was added to 4 g of 0.1% by weight aqueous solution of the copolymer to be measured, and the dispersion was stirred. After putting 0.3 g of iron oxide hydroxide (III) (manufactured by Kanto Chemical) into a test tube (made by IWAKI GLASS, diameter 18 mm, height 180 mm), 30 g of the above dispersion was added and sealed. After shaking the tube to uniformly disperse the iron hydroxide, the test tube was allowed to stand for 20 hours, and then 5 cc of the supernatant was taken and the absorbance was measured with a UV spectrometer (wavelength 380 nm). It shows that iron hydroxide dispersibility is so high.

<Monomer Synthesis Example 1>
Using a 1 L four-necked flask, 400 g of IPN10, 351.4 g of epichlorohydrin, and 94.9 g of 48% by mass aqueous sodium hydroxide (hereinafter also referred to as “48% NaOH”) were charged and stirred for 6 hours while maintaining at 50 ° C. And reacted. After the reaction, the generated salt was removed, and then the epichlorohydrin and water were removed from the remaining organic layer to obtain 451.2 g of a reaction solution containing 324.9 g of intermediate (IPEG10) and 64.1 g of IPN10. . Next, using a 1 L four-necked flask, 451.2 g of a reaction solution containing 324.9 g of IPEG10 and 268.7 g of 30% by mass trimethylamine hydrochloride aqueous solution were charged and reacted for 8 hours while maintaining at 50 ° C. 719.9 g of a reaction solution (hereinafter referred to as monomer composition (1)) containing 336.4 g (hereinafter also referred to as IPEC10) and 63.8 g of IPN10 was obtained.

<Monomer Synthesis Example 2>
100.0 g of IPEG10 synthesized in the same manner as in Synthesis Example 1 and 17.4 g of diethanolamine were charged and stirred for 8 hours while maintaining at 80 ° C., to obtain 117.4 g of a monomer composition (2). As a result of analysis by liquid chromatography, an amination product of IPN10 (that is, in which two organic groups bonded to the nitrogen atom in R ³ in the general formula (1) are —CH ₂ CH ₂ OH groups, hereinafter referred to as IPEA10-DEA) 102.3 g) and IPN10 (4.3 g).

<Production of amphoteric polymer>
<Example 1>
A 500 mL glass separable flask equipped with a reflux condenser and a stirrer (paddle blade) was charged with 40.0 g of pure water and 0.0018 g of Mole salt, and heated to 70 ° C. while stirring to polymerize. The reaction system was used. Next, in a polymerization reaction system maintained at 70 ° C. with stirring, 45.0 g of an 80% aqueous acrylic acid solution (hereinafter referred to as 80% AA), 57.8 g of monomer composition (1), 60 % IPN50 aqueous solution 36.5 g, 15% sodium persulfate aqueous solution (hereinafter referred to as 15% NaPS) 26.0 g, 35% sodium bisulfite (hereinafter referred to as 35% SBS) 23.9 g, respectively. It was dripped from the nozzle.
The dripping start of each solution is simultaneous, and the dropping time of each solution is 180 minutes for 80% AA, 120 minutes for monomer composition (1), 120 minutes for 60% IPN50, and 15% NaPS. 190 minutes and 35% SBS for 180 minutes. Moreover, the dropping rate of each solution was made constant, and each solution was dropped continuously. After completion of the dropwise addition of 15% NaPS, the reaction solution was kept at 70 ° C. (ripening) for 30 minutes to complete the polymerization. After completion of the polymerization, the polymerization reaction solution was stirred and allowed to cool, and then neutralized by adding 29.2 g of 48% sodium hydroxide (hereinafter abbreviated as 48% NaOH). Thus, an amphoteric polymer composition (1) containing a copolymer (1) and having a solid content concentration of 46% was obtained. The weight average molecular weight was 50000.

<Example 2>
A 500 mL glass separable flask equipped with a reflux condenser and a stirrer (paddle blade) was charged with 45.0 g of pure water and 0.0012 g of Mole salt, and the temperature was raised to 70 ° C. while stirring to polymerize. The reaction system was used. Next, 40.5 g of 80% AA, 27.9 g of monomer composition (2), 38.8 g of 60% IPN50 aqueous solution, and 15% NaPS in a polymerization reaction system maintained at 70 ° C. with stirring. 23.3 g, 35% SBS 5.0 g, and pure water 9.9 g were dropped from separate nozzles.
The dropping start of each solution is simultaneous, and the dropping time of each solution is 180 minutes for 80% AA, 150 minutes for monomer composition (2), 150 minutes for 60% IPN50, and 15% NaPS. 190 minutes and 35% SBS for 180 minutes. Moreover, the dropping rate of each solution was made constant, and each solution was dropped continuously. After completion of the dropwise addition of 15% NaPS, the reaction solution was kept at 70 ° C. (ripening) for 30 minutes to complete the polymerization. After completion of the polymerization, the polymerization reaction solution was stirred and allowed to cool, and then 26.3 g of 48% sodium hydroxide (hereinafter abbreviated as 48% NaOH) was added for neutralization. Thus, an amphoteric polymer composition (2) having a solid content concentration of 45% containing the copolymer (2) was obtained. The weight average molecular weight was 50000.

<Comparative Example 1>
A 500 mL glass separable flask equipped with a reflux condenser and a stirrer (paddle blade) was charged with 50.0 g of pure water and 0.0018 g of Mole salt, and the temperature was raised to 70 ° C. while stirring to polymerize. The reaction system was used. Next, 45.0 g of 80% AA, 57.8 g of monomer composition (1), 27.3 g of 80% IPN10 aqueous solution, and 15% NaPS in a polymerization reaction system maintained at 70 ° C. with stirring. 27.7 g, 35% SBS 5.1 g, and pure water 11.6 g were dropped from separate nozzles.
The dripping start of each solution is simultaneous, and the dripping time of each solution is 180 minutes for 80% AA, 150 minutes for monomer composition (1), 150 minutes for 80% IPN10, and 15% NaPS. 190 minutes, 35% SBS for 180 minutes, and pure water for 180 minutes. Moreover, the dropping rate of each solution was made constant, and each solution was dropped continuously. After completion of the dropwise addition of 15% NaPS, the reaction solution was kept at 70 ° C. (ripening) for 30 minutes to complete the polymerization. After completion of the polymerization, the polymerization reaction solution was stirred and allowed to cool, and then neutralized by adding 29.2 g of 48% NaOH. In this way, a comparative amphoteric polymer composition (1) having a solid content concentration of 46% containing the comparative copolymer (1) was obtained. The weight average molecular weight was 46000.

<Example 3>
The polymer compositions (1) to (2) and the comparative polymer compositions (1) to (2) were evaluated for calcium carbonate dispersibility and iron hydroxide dispersibility according to the above-described methods. The results are summarized in Table 1.

As is clear from Table 1, the amphoteric polymer in the present invention has significantly superior calcium carbonate dispersibility and iron hydroxide dispersibility compared to conventional comparative amphoteric polymer compositions. From the above, it has been clarified that the amphoteric polymer of the present invention can be preferably used as an additive for water treatment agents.

Claims (2)

The structural unit (a) derived from the cationic group-containing monomer (A) represented by the following general formula (1), and the polyalkylene glycol monomer (B) represented by the following general formula (2) An amphoteric polymer essentially comprising a structural unit derived from (b) and a structural unit derived from a carboxyl group-containing monomer (C) (c),
Structural unit derived from polyalkylene glycol monomer (B) and average added mole number n indicating repeat of alkylene glycol unit contained in structural unit (a) derived from cationic group-containing monomer (A) The average added mole number m indicating the repetition of the alkylene glycol unit contained in (b) is a relationship of m> n,
The amphoteric polymer contains 1 to 98% by mass of the structural unit (a) with respect to 100% by mass of the total amount of structural units derived from all monomers forming the amphoteric polymer, and includes the structural unit (b). An amphoteric polymer containing 1 to 98% by mass and containing 1 to 98% by mass of the structural unit (c).

In the general formula (1), R ⁰ represents a hydrogen atom or a CH ₃ group. R ¹ represents a CH ₂ group, a CH ₂ CH ₂ group, a CO group (carbonyl group) or a direct bond. R ² represents an organic group having 1 to 5 carbon atoms.
R ³ represents a nitrogen atom-containing substituent, and the other substituent is a hydrogen atom, a tertiary amine having 1 to 60 carbon atoms, or a quaternary ammonium salt. Z is the same or different and represents an alkylene group having 2 to 20 carbon atoms. n is the average addition mole number of an oxyalkylene group (—Z—O—) and represents a number of 1 to 300.

In the general formula (2), R ⁰ represents a hydrogen atom or a CH ₃ group. R ¹ represents a CH ₂ group, a CH ₂ CH ₂ group, a CO group (carbonyl group) or a direct bond. Z is the same or different and represents an alkylene group having 2 to 20 carbon atoms. m is an average addition mole number of an oxyalkylene group (—Z—O—) and represents a number of 1 to 300. Y represents a hydrogen atom or an organic group having 8 to 20 carbon atoms. A cationic group-containing monomer (A) represented by the following general formula (1), a polyalkylene glycol monomer (B) represented by the following general formula (2), and a carboxyl group-containing monomer ( A process for producing an amphoteric polymer comprising a step of polymerizing (C) with:
The average addition mole number n indicating the repetition of alkylene glycol units contained in the structural unit (a) derived from the cationic group-containing monomer (A) represented by the following general formula (1) and the following general formula The average added mole number m indicating the repetition of the alkylene glycol unit contained in the structural unit (b) derived from the polyalkylene glycol monomer (B) represented by (2) is such that m> n. And
In the production method, the monomer (A) is 1 to 98% by mass, the monomer (B) is 1 to 98% by mass, the monomer (C ) Is used in an amount of 1 to 98% by mass.

In the general formula (1), R ⁰ represents a hydrogen atom or a CH ₃ group. R ¹ represents a CH ₂ group, a CH ₂ CH ₂ group, a CO group (carbonyl group) or a direct bond. R ² represents an organic group having 1 to 5 carbon atoms.
R ³ represents a nitrogen atom-containing substituent, and the other substituent is a hydrogen atom, a tertiary amine having 1 to 60 carbon atoms, or a quaternary ammonium salt. Z is the same or different and represents an alkylene group having 2 to 20 carbon atoms. n is the average addition mole number of an oxyalkylene group (—Z—O—) and represents a number of 1 to 300.

In the general formula (2), R ⁰ represents a hydrogen atom or a CH ₃ group. R ¹ represents a CH ₂ group, a CH ₂ CH ₂ group, a CO group (carbonyl group) or a direct bond. Z is the same or different and represents an alkylene group having 2 to 20 carbon atoms. m is an average addition mole number of an oxyalkylene group (—Z—O—) and represents a number of 1 to 300. Y represents a hydrogen atom or an organic group having 8 to 20 carbon atoms.