JP2018111625A - Cement admixture and cement composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cement admixture capable of significantly improving strength of a cured product of a cement composition over a long period of time and to provide a cement composition.SOLUTION: There is provided a cement admixture which comprises a polyoxyalkylene compound (A), an alkanolamine compound (B) and a dispersant (C). The polyoxyalkylene compound (A) is at least one selected from (i) a copolymer (A1) having a structural unit (I) derived from a specific unsaturated polyalkylene glycol-based monomer (a), a structural unit (II) derived from an unsaturated amide-based monomer (b) and/or a structural unit (III) derived from a hydroxy alkyl ester (c) of an unsaturated carboxylic acid; (ii) a polymer (A2) having a structural unit derived from an alkylene oxide adduct of an unsaturated carboxylic acid, (iii) an alkylene oxide adduct (A3) of a trivalent or more polyhydric alcohol and (iv) a polyalkylene glycol (A4). The dispersant (C) is composed of a specific carboxylic acid.SELECTED DRAWING: None

Description

  The present invention relates to a cement admixture and a cement composition.

  Cement compositions such as mortar and concrete generally include cement, aggregate, and water, and preferably further include a cement admixture to increase fluidity and reduce water.

  Recently, there has been an increasing demand for cement compositions to improve the strength performance of cured products in addition to the improvement of water reduction performance. For example, depending on the use of the cement composition, early strength development is desired, and various studies have been made (for example, Patent Document 1).

  On the other hand, depending on the use of the cement composition, an improvement in the strength of the cured product of the cement composition over a long period of time (for example, an improvement in strength at the 4-week level) has been required.

JP 2011-84459 A

  The subject of this invention is providing the cement admixture which can improve the intensity | strength of the hardened | cured material of a cement composition notably over a long period of time. Moreover, it is providing the cement composition which the intensity | strength of hardened | cured material can improve notably over a long term.

（一般式（５）中、Ｒ^１４およびＲ^１５は、同一または異なって、水素原子またはメチル基を表し、Ｒ^１６は、水素原子または炭素原子数１〜３０の炭化水素基を表し、Ａ^２Ｏは、炭素原子数２〜１８のオキシアルキレン基を表し、ｎは、Ａ^２Ｏで表されるオキシアルキレン基の平均付加モル数を表し、ｎは２〜３００である。） The cement admixture of the present invention is
A cement admixture comprising a polyoxyalkylene compound (A), an alkanolamine compound (B) and a dispersant (C),
The polyoxyalkylene compound (A) is
(I) General formula (1): Unsaturated polyalkylene glycol ether monomer (a) represented by YO (A ¹ O) _m R ⁰ (in general formula (1), Y is 2 carbon atoms) Represents an alkenyl group having ˜8, R ⁰ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, A ¹ O represents an oxyalkylene group having 2 to 18 carbon atoms, and m represents A ¹ represents the average number of added moles of the oxyalkylene group represented by ¹ O, and m is 2 to 300.) derived from the structural unit (I) and the unsaturated amide monomer (b) (II) And / or a copolymer (A1) having a structural unit (III) derived from a hydroxyalkyl ester (c) of an unsaturated carboxylic acid,
(Ii) a polymer (A2) having a structural unit derived from an alkylene oxide adduct of an unsaturated carboxylic acid,
(Iii) an alkylene oxide adduct of a trihydric or higher polyhydric alcohol (A3),
(Iv) polyalkylene glycol (A4),
At least one selected from
The dispersant (C) is
(V) a combination (C1) of two or more different polycarboxylic acid dispersants (Ca),
(Vi) a combination (C2) of at least one polycarboxylic acid dispersant (Ca) and at least one polycarboxylic acid dispersant (Cb);
Is at least one selected from
The polycarboxylic acid dispersant (C-a) is an unsaturated polyalkylene glycol ether monomer (a) represented by the general formula (1): YO (A ¹ O) _m R ⁰ (general formula (1 ) Represents an alkenyl group having 2 to 8 carbon atoms, R ⁰ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and A ¹ O represents 2 to 18 carbon atoms. Represents an oxyalkylene group, m represents the average number of added moles of the oxyalkylene group represented by A ¹ O, and m is from 2 to 300.) derived from the structural unit (I) and the unsaturated carboxylic acid group It is a polycarboxylic acid copolymer having a structural unit (IV) derived from a monomer (d).
The polycarboxylic acid dispersant (Cb) is composed of the structural unit (VI) derived from the unsaturated polyalkylene glycol ester monomer (f) represented by the general formula (5) and the unsaturated monocarboxylic acid monomer. It is a copolymer having the structural unit (VII) derived from the monomer (g).

(In the general formula ^{(5), R 14} and ^{R 15} are the same or different, represent a hydrogen atom or a methyl ^{group, R 16} represents a hydrogen atom or a hydrocarbon group having a carbon number of 1 to 30, ^{A 2} O represents an oxyalkylene group having 2 to 18 carbon atoms, n represents the average number of added moles of the oxyalkylene group represented by A ² O, and n is 2 to 300.)

（一般式（５）中、Ｒ^１４およびＲ^１５は、同一または異なって、水素原子またはメチル基を表し、Ｒ^１６は、水素原子または炭素原子数１〜３０の炭化水素基を表し、Ａ^２Ｏは、炭素原子数２〜１８のオキシアルキレン基を表し、ｎは、Ａ^２Ｏで表されるオキシアルキレン基の平均付加モル数を表し、ｎは２〜３００である。） The cement composition of the present invention comprises:
A cement composition comprising a polyoxyalkylene compound (A), an alkanolamine compound (B), a dispersant (C) and cement,
The polyoxyalkylene compound (A) is
(I) General formula (1): Unsaturated polyalkylene glycol ether monomer (a) represented by YO (A ¹ O) _m R ⁰ (in general formula (1), Y is 2 carbon atoms) Represents an alkenyl group having ˜8, R ⁰ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, A ¹ O represents an oxyalkylene group having 2 to 18 carbon atoms, and m represents A ¹ represents the average number of added moles of the oxyalkylene group represented by ¹ O, and m is 2 to 300.) derived from the structural unit (I) and the unsaturated amide monomer (b) (II) And / or a copolymer (A1) having a structural unit (III) derived from a hydroxyalkyl ester (c) of an unsaturated carboxylic acid,
(Ii) a polymer (A2) having a structural unit derived from an alkylene oxide adduct of an unsaturated carboxylic acid,
(Iii) an alkylene oxide adduct of a trihydric or higher polyhydric alcohol (A3),
(Iv) polyalkylene glycol (A4),
At least one selected from
The dispersant (C) is
(V) a combination (C1) of two or more different polycarboxylic acid dispersants (Ca),
(Vi) a combination (C2) of at least one polycarboxylic acid dispersant (Ca) and at least one polycarboxylic acid dispersant (Cb);
Is at least one selected from
The polycarboxylic acid dispersant (C-a) is an unsaturated polyalkylene glycol ether monomer (a) represented by the general formula (1): YO (A ¹ O) _m R ⁰ (general formula (1 ) Represents an alkenyl group having 2 to 8 carbon atoms, R ⁰ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and A ¹ O represents 2 to 18 carbon atoms. Represents an oxyalkylene group, m represents the average number of added moles of the oxyalkylene group represented by A ¹ O, and m is from 2 to 300.) derived from the structural unit (I) and the unsaturated carboxylic acid group It is a polycarboxylic acid copolymer having a structural unit (IV) derived from a monomer (d).
The polycarboxylic acid dispersant (Cb) is composed of the structural unit (VI) derived from the unsaturated polyalkylene glycol ester monomer (f) represented by the general formula (5) and the unsaturated monocarboxylic acid monomer. It is a copolymer having the structural unit (VII) derived from the monomer (g).

(In the general formula ^{(5), R 14} and ^{R 15} are the same or different, represent a hydrogen atom or a methyl ^{group, R 16} represents a hydrogen atom or a hydrocarbon group having a carbon number of 1 to 30, ^{A 2} O represents an oxyalkylene group having 2 to 18 carbon atoms, n represents the average number of added moles of the oxyalkylene group represented by A ² O, and n is 2 to 300.)

  ADVANTAGE OF THE INVENTION According to this invention, the cement admixture which can improve the intensity | strength of the hardened | cured material of a cement composition notably over a long period can be provided. Moreover, the cement composition which can improve the intensity | strength of hardened | cured material notably over a long term can be provided.

  In the present specification, the expression “(meth) acryl” means “acryl and / or methacryl”, and the expression “(meth) acrylate” means “acrylate and / or methacrylate”. Means “allyl and / or methallyl”, and “(meth) acrolein” means “acrolein and / or methacrole”. It means "rain". Further, in the present specification, the expression “acid (salt)” means “acid and / or salt thereof”.

≪≪Cement admixture≫≫
The cement admixture of the present invention contains a polyoxyalkylene compound (A), an alkanolamine compound (B), and a dispersant (C).

  1 type may be sufficient as a polyoxyalkylene compound (A), and 2 or more types may be sufficient as it.

  1 type may be sufficient as an alkanolamine compound (B), and 2 or more types may be sufficient as it.

  1 type may be sufficient as a dispersing agent (C), and 2 or more types may be sufficient as it.

  The cement admixture of the present invention includes the polyoxyalkylene compound (A), the alkanolamine compound (B), and the dispersant (C), thereby contributing to improvement in the dispersibility of the cement composition, and the cement composition. The effect of significantly improving the strength of the cured product over a long period of time is exhibited.

  The content ratio of the total amount of the polyoxyalkylene compound (A), the alkanolamine compound (B) and the dispersant (C) in the cement admixture of the present invention is preferably 50% by mass to 100% by mass, and more Preferably it is 70 mass%-100 mass%, More preferably, it is 90 mass%-100 mass%, Most preferably, it is 95 mass%-100 mass%, Most preferably, it is substantially 100 mass%. That is, most preferably, the cement admixture of the present invention comprises only the polyoxyalkylene compound (A), the alkanolamine compound (B), and the dispersant (C). By adjusting the content ratio of the total amount of the polyoxyalkylene compound (A), the alkanolamine compound (B) and the dispersant (C) in the cement admixture of the present invention within the above range, the cement admixture of the present invention is adjusted. The agent can significantly improve the strength of the cured product of the cement composition over a long period of time.

  The content ratio of the polyoxyalkylene compound (A) in the cement admixture of the present invention is preferably 0.5% by mass to 80% by mass, more preferably 1% by mass to 70% by mass, and still more preferably. It is 3 mass%-60 mass%, Most preferably, it is 5 mass%-50 mass%, Most preferably, it is 10 mass%-40 mass%. By adjusting the content ratio of the polyoxyalkylene compound (A) in the cement admixture of the present invention within the above range, the cement admixture of the present invention makes the strength of the cured product of the cement composition more prominent over a long period of time. Can be improved. When the content of the polyoxyalkylene compound (A) in the cement admixture of the present invention is less than 0.5% by mass, the cement admixture of the present invention improves the strength of the cured product of the cement composition over a long period of time. May be difficult.

  The content ratio of the alkanolamine compound (B) in the cement admixture of the present invention is preferably 0.2% by mass to 80% by mass, more preferably 0.5% by mass to 70% by mass, and further preferably. Is 1% by mass to 60% by mass, and particularly preferably 3% by mass to 50% by mass. By adjusting the content ratio of the alkanolamine compound (B) in the cement admixture of the present invention within the above range, the cement admixture of the present invention significantly improves the strength of the cured product of the cement composition over a long period of time. Can be. When the content ratio of the alkanolamine compound (B) in the cement admixture of the present invention is less than 0.2% by mass, the cement admixture of the present invention is difficult to improve the strength of the cured product of the cement composition over a long period of time. There is a fear.

  The content of the dispersant (C) in the cement admixture of the present invention is preferably 25% by mass to 99% by mass, more preferably 30% by mass to 97% by mass, and further preferably 35% by mass to It is 95 mass%, Most preferably, it is 40 mass%-93 mass%, Most preferably, it is 45 mass%-90 mass%. By adjusting the content ratio of the dispersant (C) in the cement admixture of the present invention within the above range, the cement admixture of the present invention can significantly improve the dispersibility of the cement composition. When the content rate of the dispersing agent (C) in the cement admixture of the present invention is less than 25% by mass, the cement admixture of the present invention may hardly improve the dispersibility of the cement composition.

  The content ratio of the polyoxyalkylene compound (A) in the cement admixture of the present invention is preferably 0.005% by mass to 0.3% by mass, more preferably 0.01% by mass to the cement. 0.25% by mass, more preferably 0.02% by mass to 0.2% by mass, particularly preferably 0.02% by mass to 0.15% by mass, and most preferably 0.05% by mass. It is -0.1 mass%. By adjusting the content ratio of the polyoxyalkylene compound (A) in the cement admixture of the present invention within the above range, the cement admixture of the present invention makes the strength of the cured product of the cement composition more prominent over a long period of time. Can be improved. When the content ratio of the polyoxyalkylene compound (A) in the cement admixture of the present invention is less than 0.005% by mass with respect to the cement, the cement admixture of the present invention has the strength of the cured product of the cement composition. May be difficult to improve over a long period of time.

  The content ratio of the alkanolamine compound (B) in the cement admixture of the present invention is preferably 0.002% by mass to 0.2% by mass and more preferably 0.005% by mass to 0% with respect to the cement. 0.15% by mass, more preferably 0.01% by mass to 0.1% by mass, particularly preferably 0.015% by mass to 0.07% by mass, and most preferably 0.02% by mass to 0.05% by mass. By adjusting the content ratio of the alkanolamine compound (B) in the cement admixture of the present invention within the above range, the cement admixture of the present invention significantly improves the strength of the cured product of the cement composition over a long period of time. Can be. When the content ratio of the alkanolamine compound (B) in the cement admixture of the present invention is less than 0.002% by mass with respect to the cement, the cement admixture of the present invention increases the strength of the cured product of the cement composition. It may be difficult to improve over a long period of time.

  The content ratio of the dispersant (C) in the cement admixture of the present invention is preferably 0.01% by mass to 1% by mass, more preferably 0.03% by mass to 0.8% by mass with respect to the cement. %, More preferably 0.05 mass% to 0.6 mass%, particularly preferably 0.1 mass% to 0.5 mass%, and most preferably 0.15 mass% to 0.4 mass%. % By mass. By adjusting the content ratio of the dispersant (C) in the cement admixture of the present invention within the above range, the cement admixture of the present invention can significantly improve the dispersibility of the cement composition. When the content ratio of the dispersant (C) in the cement admixture of the present invention is less than 0.01% by mass with respect to the cement, the cement admixture of the present invention hardly improves the dispersibility of the cement composition. There is a fear.

  The ratio of the alkanolamine compound (B) to the polyoxyalkylene compound (A) in the cement admixture of the present invention is preferably 1% by mass to 10000% by mass, more preferably 5% by mass to 1000% by mass. Yes, more preferably 10% by mass to 500% by mass, further preferably 15% by mass to 300% by mass, further preferably 20% by mass to 200% by mass, and particularly preferably 30% by mass to 150% by mass. %, And most preferably 50% by mass to 100% by mass. By adjusting the ratio of the alkanolamine compound (B) to the polyoxyalkylene compound (A) in the cement admixture of the present invention within the above range, the cement admixture of the present invention can be used as a cured product of a cement composition. The strength can be improved more significantly over the long term.

≪Polyoxyalkylene compound (A) ≫
The polyoxyalkylene compound (A) is
(I) General formula (1): Unsaturated polyalkylene glycol ether monomer (a) represented by YO (A ¹ O) _m R ⁰ (in general formula (1), Y is 2 carbon atoms) Represents an alkenyl group having ˜8, R ⁰ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, A ¹ O represents an oxyalkylene group having 2 to 18 carbon atoms, and m represents A ¹ represents the average number of added moles of the oxyalkylene group represented by ¹ O, and m is 2 to 300.) derived from the structural unit (I) and the unsaturated amide monomer (b) (II) And / or a copolymer (A1) having a structural unit (III) derived from a hydroxyalkyl ester (c) of an unsaturated carboxylic acid,
(Ii) a polymer (A2) having a structural unit derived from an alkylene oxide adduct of an unsaturated carboxylic acid,
(Iii) an alkylene oxide adduct of a trihydric or higher polyhydric alcohol (A3),
(Iv) polyalkylene glycol (A4),
Is at least one selected from

  The polyoxyalkylene compound (A) can contribute mainly to the enhancement of the strength enhancement effect of the cured product of the cement composition in the cement admixture of the present invention.

<Copolymer (A1)>
The copolymer (A1) is composed of an unsaturated polyalkylene glycol ether monomer (a) represented by the general formula (1): YO (A ¹ O) _m R ⁰ and an unsaturated unit. It has structural unit (II) derived from amide monomer (b) and / or structural unit (III) derived from hydroxyalkyl ester (c) of unsaturated carboxylic acid. When the copolymer (A1) has such a structure, the cement admixture of the present invention can significantly improve the strength of the cured product of the cement composition over a long period of time.

The structural unit (I) derived from the unsaturated polyalkylene glycol ether monomer (a) represented by the general formula (1): YO (A ¹ O) _m R ⁰ is specifically represented by the general formula ( In the unsaturated polyalkylene glycol ether monomer (a) represented by 1), the unsaturated double bond (C═C) of Y has a structural unit converted to —C—C— by a polymerization reaction.

  In general formula (1), Y represents an alkenyl group having 2 to 8 carbon atoms.

Examples of Y include a vinyl group (CH ₂ ═CH— group), 1-methyl-1-vinyl group (CH ₂ ═C (CH ₃ ) — group), 2-propenyl group (allyl group) (CH ₂ ═ CHCH ₂ - group), 2-methyl-2-propenyl group _{(methallyl) (CH 2 = C (CH} 3) -CH 2 - group), 3-methyl-3-butenyl group (isoprenyl group) _(CH 2 = C (CH ₃ ) —CH ₂ CH ₂ — group) and the like. Among these, Preferably, a vinyl group, 2-propenyl group (allyl group), 2-methyl-2-propenyl group (methallyl group), and 3-methyl-3-butenyl group (isoprenyl group) are mentioned.

In general formula (1), R ⁰ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. Examples of the hydrocarbon group having 1 to 30 carbon atoms include an alkyl group having 1 to 30 carbon atoms (an aliphatic alkyl group and an alicyclic alkyl group), an alkenyl group having 1 to 30 carbon atoms, and the number of carbon atoms. Examples thereof include an alkynyl group having 1 to 30 carbon atoms and an aromatic group having 6 to 30 carbon atoms. R ³ is preferably a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and more preferably a hydrogen atom or a carbon atom having 1 to 12 carbon atoms in that the effects of the present invention can be further exhibited. It is a hydrogen group, more preferably a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, and particularly preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

In the general formula (1), A ¹ O represents an oxyalkylene group having 2 to 18 carbon atoms. The number of carbon atoms of the oxyalkylene group is preferably 2-8, more preferably 2-4.

Examples of A ¹ O include an oxyethylene group, an oxypropylene group, an oxybutylene group, and an oxystyrene group. Among these, an oxyethylene group, an oxypropylene group, and an oxybutylene group are preferable, and an oxyethylene group and an oxypropylene group are more preferable. When two or more different A ¹ O structures exist, these different A ¹ O structures may exist in any form such as random addition, block addition, and alternate addition. In order to secure a balance between hydrophilicity and hydrophobicity, it is preferable that an oxyethylene group contains an oxyethylene group as an essential component. More specifically, 50 mol% or more is preferably an oxyethylene group, more preferably 80 mol% or more is an oxyethylene group, and more preferably 90 mol% or more with respect to 100 mol% of all oxyalkylene groups. An oxyethylene group is particularly preferable, and 100 mol% is particularly preferably an oxyethylene group.

In the general formula (1), m represents an average addition mole number of the oxyalkylene group represented by ^{A 1} O, it is 2 to 300. n is preferably 5 to 150, more preferably 10 to 100, still more preferably 15 to 75, and particularly preferably 20 to 50. The “average number of moles added” means the average number of moles of oxyalkylene groups added in 1 mole of the compound. When m is within such a range, the cement admixture of the present invention can significantly improve the strength of the cured product of the cement composition over a long period of time.

The unsaturated amide monomer (b) is preferably represented by the general formula (2).

  The structural unit (II) derived from the unsaturated amide monomer (b) represented by the general formula (2) is specifically an unsaturated amide monomer represented by the general formula (2). It is a structural unit in which the unsaturated double bond (C═C) of (b) has become —C—C— by the polymerization reaction.

In General Formula (2), R ¹ , R ² , and R ³ are the same or different and each represents a hydrogen atom, a methyl group, or a — (CH ₂ ) _p COOM group. p is an integer of 0-2. M represents a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group.

In General Formula (2), R ⁴ and R ⁵ represent a — (CR ⁶ ₂ ) _n — (A ² O) _q — (R ⁷ ) _r —R ⁸ group. R ⁶ is a hydrogen atom or an alkyl group having 1 to 18 carbon atoms. n is an integer of 0-5. R ⁷ represents a hydrogen atom or a methylene group. r is an integer of 0-5. R ⁸ represents a hydrogen atom, a phosphoric acid (salt) group, a sulfonic acid (salt) group, a carboxylic acid (salt) group, or a hydroxyl group.

In the general formula (2), A ² O represents an oxyalkylene group having 2 to 18 carbon atoms. A ² O is preferably an oxyalkylene group having 2 to 8 carbon atoms, and more preferably an oxyalkylene group having 2 to 4 carbon atoms, in that the effects of the present invention can be further exhibited. When A ² O is any two or more selected from oxyethylene group, oxypropylene group, oxybutylene group, oxystyrene group, etc., the addition form of A ² O is random addition or block addition. Any form such as alternate addition may be used. In order to secure a balance between hydrophilicity and hydrophobicity, it is preferable that the oxyalkylene group contains an oxyethylene group as an essential component, and more than 50 mol% of the entire oxyalkylene group is an oxyethylene group. Preferably, 90 mol% or more of the entire oxyalkylene group is more preferably an oxyethylene group, more preferably 95 mol% or more of the entire oxyalkylene group is an oxyethylene group, and 100 mol% of the entire oxyalkylene group. Is most preferably an oxyethylene group.

In formula (2), q represents an average addition mole number of the oxyalkylene group represented by ^{A 2} O, it is 0-200. Q is preferably 0 to 180, more preferably 0 to 160, still more preferably 0 to 140, and particularly preferably 0 to 120, in that the effects of the present invention can be further exhibited. Most preferably, it is 0-100.

  Examples of the unsaturated amide monomer (b) represented by the general formula (2) include (meth) acrylic (alkyl) amide, N-methylol (meth) acrylamide, and N, N-dimethyl (meth) acrylamide. Etc.

  The unsaturated amide monomer (b) represented by the general formula (2) is preferably acrylamide in that the effects of the present invention can be further exhibited.

  The unsaturated amide monomer (b) represented by the general formula (2) may be only one type or two or more types.

  The structural unit (III) derived from the hydroxyalkyl ester (c) of the unsaturated carboxylic acid is specifically an unsaturated double bond (C = C) of the hydroxyalkyl ester (c) of the unsaturated carboxylic acid. It is a structural unit converted to -C-C- by the polymerization reaction.

  The hydroxyalkyl ester of unsaturated carboxylic acid (c) is preferably a hydroxyalkyl ester of (meth) acrylic acid, more preferably a hydroxyethyl ester of (meth) acrylic acid or a hydroxypropyl ester of (meth) acrylic acid. An ester, more preferably a hydroxyethyl ester of (meth) acrylic acid, specifically, hydroxyethyl acrylate or hydroxypropyl acrylate.

  The hydroxyalkyl ester (c) of unsaturated carboxylic acid may be only one type or two or more types.

  In the copolymer (A1), in addition to the structural unit (I), the structural unit (II) and / or the structural unit (III), the structural unit (IV) derived from the unsaturated carboxylic acid monomer (d). And / or a structural unit (V) derived from another monomer (e). Specific examples of the unsaturated carboxylic acid monomer (d) are as described below.

  The other monomer (e) is a monomer copolymerizable with the monomer (a), the monomer (b), the monomer (c), and the monomer (d). Only one type of other monomer (e) may be used, or two or more types may be used.

  Examples of the other monomer (e) include alkoxy (poly) alkylene glycol and (meth) acryl obtained by adding an average of 1 to 500 moles of an alkylene oxide having 2 to 18 carbon atoms to an alcohol having 1 to 30 carbon atoms. Esters with unsaturated monocarboxylic acids such as acid and crotonic acid; Esters with unsaturated monocarboxylic acids such as methyl (meth) acrylate and glycidyl (meth) acrylate and alcohols having 1 to 30 carbon atoms; ) Half esters of unsaturated dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid and alcohols having 1 to 30 carbon atoms; (anhydrous) unsaturated dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid and carbon atoms Diesters with alcohols of 1 to 30; diesters of unsaturated dicarboxylic acids with amines of 1 to 30 carbon atoms Mids; half esters of an alkoxy (poly) alkylene glycol obtained by adding 1 to 500 moles of an alkylene oxide having 2 to 18 carbon atoms to the alcohol or amine and an unsaturated dicarboxylic acid; carbon to the alcohol or amine Diesters of an alkoxy (poly) alkylene glycol and an unsaturated dicarboxylic acid obtained by adding an average of 1 to 500 moles of an alkylene oxide having 2 to 18 atoms; an unsaturated dicarboxylic acid and a glycol having 2 to 18 carbon atoms or these Half esters of polyalkylene glycols having an average addition mole number of 2 to 500 glycols; glycols having the above unsaturated dicarboxylic acids and 2 to 18 carbon atoms, or polyalkylene glycols having an average addition mole number of these glycols of 2 to 500 And diesters; (Poly) ethylene glycol di (meth) acrylate, (poly) alkylene glycol di (meth) acrylates such as (poly) propylene glycol di (meth) acrylate; hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate Polyfunctional (meth) acrylates such as; (poly) alkylene glycol dimaleates such as polyethylene glycol dimaleate; vinyl sulfonate, (meth) allyl sulfonate, 2-methylpropane sulfonic acid (meth) acrylamide, styrene sulfonic acid, etc. Unsaturated sulfonic acids (salts); vinyl aromatics such as styrene, α-methylstyrene and vinyltoluene; alkanediol mono (meth) acrylates such as 1,4-butanediol mono (meth) acrylate; Dienes such as ethylene and isoprene; unsaturated cyanides such as (meth) acrylonitrile; unsaturated esters such as vinyl acetate; unsaturated esters such as aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, and vinylpyridine. Saturated amines; Divinyl aromatics such as divinylbenzene; Allyls such as (meth) allyl alcohol and glycidyl (meth) allyl ether; Examples of the salt herein include alkali metal salts, alkaline earth metal salts, ammonium salts, organic ammonium salts, and organic amine salts. Examples of the alkali metal salt include lithium salt, sodium salt, potassium salt and the like. Examples of alkaline earth metal salts include calcium salts and magnesium salts. Examples of the organic ammonium salt include methyl ammonium salt, ethyl ammonium salt, dimethyl ammonium salt, diethyl ammonium salt, trimethyl ammonium salt, and triethyl ammonium salt. Examples of organic amine salts include ethanolamine salts, diethanolamine salts, triethanolamine salts, alkanolamine salts such as triisopropanolamine salts, and the like.

  In the copolymer (A1), the content ratio of the structural unit having a carboxyl group or a salt thereof is preferably less than 20 mol%, preferably 0 mol% to 15 mol% with respect to all the structural units constituting the copolymer (A1). More preferably, it is 0 mol%-10 mol%, More preferably, it is 0 mol%-5 mol%, Most preferably, it is 0 mol%-3 mol%. When the content ratio of the structural unit having a carboxyl group or a salt thereof with respect to all the structural units constituting the copolymer (A1) is within the above range, the cement admixture of the present invention has the strength of the cured product of the cement composition. Can be significantly improved over a long period of time. The “carboxyl group or a salt thereof” herein is a group represented by —COOM, and M is a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group. .

  When the copolymer (A1) contains a structural unit derived from another copolymerizable monomer, the total content ratio of the structural unit (I) and the structural unit (II) and / or the structural unit (III) is In the copolymer (A1), the structural unit (I) and the structural unit (II) and / or the structural unit (III) are preferably the main components in the structural unit constituting the polymer. Is preferably 51% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, still more preferably 90% by mass to 100% by mass, and particularly preferably 95% by mass. % By mass to 100% by mass, most preferably substantially 100% by mass. When the total content of the structural unit (I) and the structural unit (II) and / or the structural unit (III) in the copolymer (A1) is within the above range, the cement admixture of the present invention is The strength of the cured product of the cement composition can be more significantly improved over a long period of time.

  The content ratio of the structural unit (I) to the structural unit (II) and / or the structural unit (III) in the copolymer (A1) is as follows: structural unit (I) / structural unit (II) and / or structural unit The mass ratio of (III) is preferably 99/1 wt% to 1/99 wt%, more preferably 98/2 wt% to 5/95 wt%, and even more preferably 95/5 wt% to It is 10/90% by weight, particularly preferably 93/7% by weight to 20/80% by weight, and most preferably 90/10% by weight to 30/70% by weight. When the content ratio of the structural unit (I) to the structural unit (II) and / or the structural unit (III) in the copolymer (A1) is within the above range, the cement admixture of the present invention can be used as a cement. The strength of the cured product of the composition can be significantly improved over a long period of time.

  The content rate of each structural unit in a copolymer (A1) can be known by various structural analysis (for example, NMR etc.) of this copolymer (A1), for example. Moreover, the structure derived from this monomer calculated based on the usage-amount and the polymerization rate of each monomer used when manufacturing a copolymer (A1), without performing the above various structural analyses. It is good also as a content rate of each structural unit in a copolymer (A1) with the content rate of a unit.

  When calculating | requiring the content rate of the structural unit in a copolymer (A1), when a structural unit has a carboxyl group, it calculates as what was completely neutralized (sodium salt).

  The weight average molecular weight (Mw) of the copolymer (A1) is preferably 3000 or more, more preferably from 4,000 to 1,000,000, further preferably from 5,000 to 500,000, particularly preferably from 10,000 to 300,000. Preferably it is 30000-200000. When the mass average molecular weight (Mw) of the copolymer (A1) is within the above range, the cement admixture of the present invention can significantly improve the strength of the cured product of the cement composition over a long period of time.

  The copolymer (A1) can be produced by any appropriate method as long as the effects of the present invention are not impaired. The copolymer (A1) is preferably an unsaturated polyalkylene glycol ether monomer (a), an unsaturated amide monomer (b) and / or a hydroxyalkyl ester (c) of an unsaturated carboxylic acid. The monomer component containing can be produced in the presence of a polymerization initiator.

  Unsaturated polyalkylene glycol ether monomers (a), unsaturated amide monomers (b) and / or hydroxyalkyl esters of unsaturated carboxylic acids (c) that can be used for the production of the copolymer (A1), If necessary, the amount of the unsaturated carboxylic acid monomer (d) and / or other monomer (e) used may be selected from each single unit in all the structural units constituting the copolymer (A1). What is necessary is just to adjust suitably so that the ratio of the structural unit derived from a monomer may become what was mentioned above.

  The polymerization of the monomer component can be performed by any appropriate method. Examples thereof include solution polymerization and bulk polymerization. Examples of the solution polymerization method include a batch method and a continuous method. Solvents that can be used in the solution polymerization include water; alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; aromatic or aliphatic hydrocarbons such as benzene, toluene, xylene, cyclohexane, and n-hexane; esters such as ethyl acetate. Compounds; ketone compounds such as acetone and methyl ethyl ketone; cyclic ether compounds such as tetrahydrofuran and dioxane; and the like.

  When the monomer component is polymerized, a water-soluble polymerization initiator, for example, a persulfate such as ammonium persulfate, sodium persulfate, or potassium persulfate; hydrogen peroxide; 2,2′- Azoamidine compounds such as azobis-2-methylpropionamidine hydrochloride, cyclic azoamidine compounds such as 2,2′-azobis-2- (2-imidazolin-2-yl) propane hydrochloride, 2-carbamoylazoisobutyronitrile, etc. Water-soluble azo initiators such as azonitrile compounds of These polymerization initiators include alkali metal sulfites such as sodium hydrogen sulfite, metabisulfites, sodium hypophosphite, Fe (II) salts such as molle salts, sodium hydroxymethanesulfinate dihydrate, hydroxylamine hydrochloride Accelerators such as salt, thiourea, L-ascorbic acid (salt), and erythorbic acid (salt) can also be used in combination. Among these combined forms, a combination of hydrogen peroxide and an accelerator such as L-ascorbic acid (salt) is preferable. These polymerization initiators and accelerators may be used alone or in combination of two or more.

  When performing solution polymerization using a lower alcohol, aromatic hydrocarbon, aliphatic hydrocarbon, ester compound, or ketone compound as a solvent, or when performing bulk polymerization, benzoyl peroxide, lauroyl peroxide may be used as a polymerization initiator. Peroxides such as oxide and sodium peroxide; hydroperoxides such as t-butyl hydroperoxide and cumene hydroperoxide; azo compounds such as azobisisobutyronitrile; When such a polymerization initiator is used, an accelerator such as an amine compound can be used in combination. Furthermore, when a water-lower alcohol mixed solvent is used, it can be appropriately selected from the above-mentioned various polymerization initiators or combinations of polymerization initiators and accelerators.

  The reaction temperature for the polymerization of the monomer component is appropriately determined depending on the polymerization method, solvent, polymerization initiator, and chain transfer agent used. The reaction temperature is preferably 0 ° C. or higher, more preferably 30 ° C. or higher, further preferably 50 ° C. or higher, preferably 150 ° C. or lower, more preferably 120 ° C. or lower. More preferably, it is 100 ° C. or lower.

  Any appropriate method can be adopted as a method of charging the monomer component into the reaction vessel. As such a charging method, for example, a method in which the entire amount is initially charged into the reaction vessel, a method in which the entire amount is divided or continuously charged into the reaction vessel, a part is initially charged in the reaction vessel, and the rest is put in the reaction vessel. The method of dividing | segmenting or carrying out continuously etc. is mentioned. Specifically, a method of continuously charging the total amount of the monomer (a) and the total amount of the monomer (b) and / or the monomer (c) into the reaction vessel, a part of the monomer (a) Is initially charged into the reaction vessel, and the remaining monomer (a) and the total amount of monomer (b) and / or monomer (c) are continuously charged into the reaction vessel, monomer (a ) And a part of monomer (b) and / or monomer (c) are initially charged into the reaction vessel, and the remainder of monomer (a) and monomer (b) and / or Alternatively, there may be mentioned a method in which the remainder of the monomer (c) is alternately divided into several times in a reaction vessel. Furthermore, by changing the charging rate of each monomer into the reaction vessel during the reaction continuously or stepwise, the charging mass ratio per unit time of each monomer is changed continuously or stepwise, You may make it synthesize | combine simultaneously the 2 or more types of copolymer from which the ratio of structural unit (I), structural unit (II), and / or structural unit (III) differs. The polymerization initiator may be charged into the reaction vessel from the beginning, may be dropped into the reaction vessel, or these may be combined according to the purpose.

  In the polymerization of the monomer component, a chain transfer agent can be preferably used. When a chain transfer agent is used, the molecular weight of the resulting copolymer can be easily adjusted. Only one type of chain transfer agent may be used, or two or more types may be used.

  Any appropriate chain transfer agent can be adopted as the chain transfer agent. Examples of such chain transfer agents include thiol chain transfer agents such as mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, and 2-mercaptoethanesulfonic acid; Secondary alcohols such as isopropanol; phosphorous acid, hypophosphorous acid, and salts thereof (sodium hypophosphite, potassium hypophosphite, etc.), sulfurous acid, hydrogen sulfite, dithionite, metabisulfite, And lower salts of salts thereof (sodium sulfite, potassium sulfite, sodium hydrogen sulfite, potassium hydrogen sulfite, sodium dithionite, potassium dithionite, sodium metabisulfite, potassium metabisulfite, etc.) and salts thereof, etc. Is mentioned.

  The produced copolymer (A1) can be used as it is as the copolymer (A1), but from the viewpoint of handleability, the pH of the reaction solution after the production of the copolymer (A1) is 5 or more. It is preferable to adjust. However, in order to improve the polymerization rate, it is preferable to perform the polymerization at a pH of less than 5 and adjust the pH to 5 or more after the polymerization. The pH can be adjusted, for example, using an alkaline substance such as an inorganic salt such as monovalent metal or divalent metal hydroxide or carbonate; ammonia; organic amine;

  The produced copolymer (A1) can be subjected to concentration adjustment, if necessary, with respect to the solution obtained by the production.

  The produced copolymer (A1) may be used as it is in the form of a solution, or is neutralized with a hydroxide of a divalent metal such as calcium or magnesium to obtain a polyvalent metal salt and then dried. Or may be used after being powdered by being supported on an inorganic powder such as silica-based fine powder and drying.

<Polymer (A2)>
The polymer (A2) is a polymer having a structural unit derived from an alkylene oxide adduct of an unsaturated carboxylic acid.

  The structural unit derived from an alkylene oxide adduct of an unsaturated carboxylic acid specifically refers to an unsaturated double bond (C═C) of the alkylene oxide adduct of an unsaturated carboxylic acid formed by a polymerization reaction. It is the structural unit that became-.

  Examples of the unsaturated carboxylic acid include monocarboxylic acids such as (meth) acrylic acid and crotonic acid; dicarboxylic acids such as maleic acid, itaconic acid and fumaric acid; and dicarboxylic acid-based monocarboxylic acids such as maleic acid, itaconic acid and fumaric acid. And the like, and the like.

  The unsaturated carboxylic acid is preferably a monocarboxylic acid monomer such as (meth) acrylic acid or crotonic acid, more preferably (meth) acrylic, from the viewpoint that the effects of the present invention can be further expressed. It is an acid.

  Only one type of unsaturated carboxylic acid may be used, or two or more types may be used.

An alkylene oxide adduct of an unsaturated carboxylic acid is a product obtained by adding an alkylene oxide to a carboxyl group -COOH of an unsaturated carboxylic acid, and -COO- (AO) where the average addition mole number is t, where the alkylene oxide is AO. _{Expressed as t} H.

  The alkylene oxide is preferably an alkylene oxide having 2 to 18 carbon atoms, more preferably an alkylene oxide having 2 to 8 carbon atoms, and still more preferably an alkylene oxide having 2 to 4 carbon atoms. is there. When the alkylene oxide is any two or more selected from ethylene oxide, propylene oxide, butylene oxide, styrene oxide, etc., the addition form of alkylene oxide is any of random addition, block addition, alternating addition, etc. Form may be sufficient. In order to secure a balance between hydrophilicity and hydrophobicity, it is preferable that ethylene oxide is contained as an essential component in alkylene oxide, more preferably 50 mol% or more of the entire alkylene oxide is ethylene oxide, More preferably, 90 mol% or more is ethylene oxide, particularly preferably 95 mol% or more of the entire alkylene oxide is ethylene oxide, and most preferably 100 mol% of the entire alkylene oxide is ethylene oxide.

  The average number of added moles of alkylene oxide is preferably 2 to 300, more preferably 4 to 150, still more preferably 5 to 100, and particularly preferably 8 to 50. By adjusting the average number of added moles of alkylene oxide within the above range, the cement admixture of the present invention can significantly improve the strength of the cured product of the cement composition over a long period of time.

  In addition to the structural unit derived from an alkylene oxide adduct of an unsaturated carboxylic acid, the polymer (A2) is an unsaturated polyalkylene glycol ether monomer (a ) Derived structural unit (I), unsaturated amide monomer (b) derived structural unit (II), unsaturated carboxylic acid hydroxyalkyl ester (c) derived structural unit (III), unsaturated carboxylic acid Either the structural unit (IV) derived from the system monomer (d) or the structural unit (V) derived from another monomer (e) may be included. Specific examples of each monomer are as described above or below.

  When the polymer (A2) contains a structural unit other than a structural unit derived from an alkylene oxide adduct of an unsaturated carboxylic acid, a structural unit having a carboxyl group or a salt thereof relative to all the structural units constituting the polymer (A2) Is preferably less than 20 mol%, preferably 0 mol% to 15 mol%, more preferably 0 mol% to 10 mol%, and even more preferably 0 mol% to 5 mol%. It is particularly preferably 0 to 3 mol%. When the content ratio of the structural unit having a carboxyl group or a salt thereof with respect to all the structural units constituting the polymer (A2) is within the above range, the cement admixture of the present invention has the strength of the cured product of the cement composition. It can be improved more significantly over the long term. The “carboxyl group or a salt thereof” herein is a group represented by —COOM, and M is a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group. .

  When the polymer (A2) contains a structural unit derived from another copolymerizable monomer, the structural unit derived from an alkylene oxide adduct of an unsaturated carboxylic acid is the main component among the structural units constituting the polymer. The content ratio of the structural unit derived from the alkylene oxide adduct of unsaturated carboxylic acid in the polymer (A2) is preferably 51% by mass to 100% by mass, more preferably It is 70 mass%-100 mass%, More preferably, it is 90 mass%-100 mass%, Especially preferably, it is 95 mass%-100 mass%, Most preferably, it is substantially 100 mass%. When the content of the structural unit derived from the alkylene oxide adduct of the unsaturated carboxylic acid in the polymer (A2) is within the above range, the cement admixture of the present invention increases the strength of the cured product of the cement composition for a long time. Can be improved more significantly.

  The content rate of each structural unit in a polymer (A2) can be known by various structural analysis (for example, NMR etc.) of this polymer (A2), for example. Moreover, the structural unit derived from this monomer calculated based on the usage-amount and the polymerization rate of each monomer used when manufacturing a polymer (A2), without performing various structural analysis as mentioned above. It is good also as a content rate of each structural unit in a polymer (A2).

  When calculating | requiring the content rate of the structural unit in a polymer (A2), when a structural unit has a carboxyl group, it calculates as what was completely neutralized (sodium salt).

  The mass average molecular weight (Mw) of the polymer (A2) is preferably 3000 or more, more preferably 4,000 to 1,000,000, further preferably 5,000 to 500,000, particularly preferably 10,000 to 300,000, and most preferably. Is 30000-200000. When the mass average molecular weight (Mw) of the polymer (A2) is within the above range, the cement admixture of the present invention can remarkably improve the strength of the cured product of the cement composition over a long period of time.

<Alkylene oxide adduct of trihydric or higher polyhydric alcohol (A3)>
The alkylene oxide adduct (A3) of a trihydric or higher polyhydric alcohol is a compound obtained by adding an alkylene oxide to a trihydric or higher polyhydric alcohol.

  The trihydric or higher polyhydric alcohol may be a compound having three or more hydroxyl groups, and may be a low molecular compound or a polymer. Any appropriate trivalent or higher polyhydric alcohol may be used as long as the effects of the present invention are not impaired. Polyhydric alcohols can be employed. Such a trihydric or higher polyhydric alcohol is preferably a trivalent to 500 valent alcohol, more preferably a trivalent to 100 valent alcohol, and even more preferably a trivalent to 50 valent alcohol. . Examples of such a trihydric or higher polyhydric alcohol include glycerin and sorbitol.

  The average number of moles of alkylene oxide added per mole of trihydric or higher polyhydric alcohol is preferably 2 to 300, more preferably 5 to 150, still more preferably 10 to 100, and particularly preferably 20 to 50. By adjusting the average number of added moles of alkylene oxide to 1 mole of a trihydric or higher polyhydric alcohol within the above range, the cement admixture of the present invention significantly improves the strength of the cured product of the cement composition over a long period of time. Can be.

  The mass average molecular weight (Mw) of the alkylene oxide adduct (A3) of a trihydric or higher polyhydric alcohol is preferably 3000 or more, more preferably 4000 to 1000000, still more preferably 5000 to 500000, particularly Preferably it is 10000-300000, Most preferably, it is 30000-200000. When the mass average molecular weight (Mw) of the alkylene oxide adduct (A3) of a trihydric or higher polyhydric alcohol is within the above range, the cement admixture of the present invention can increase the strength of the cured product of the cement composition over a long period. It can be improved more significantly.

<Polyalkylene glycol (A4)>
The polyalkylene glycol (A4) is represented by the general formula (3).
_{^{R 9 - (A 3 O)}} s -R 10 (3)

In general formula (3), R <^9> , R < ¹⁰ > is the same or different and represents a hydrogen atom or a C1-C30 hydrocarbon group. Examples of the hydrocarbon group having 1 to 30 carbon atoms include an alkyl group having 1 to 30 carbon atoms (an aliphatic alkyl group and an alicyclic alkyl group), an alkenyl group having 1 to 30 carbon atoms, and the number of carbon atoms. Examples thereof include an alkynyl group having 1 to 30 carbon atoms and an aromatic group having 6 to 30 carbon atoms. R ⁹ and R ¹⁰ are preferably a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, more preferably a hydrogen atom or 1 to 1 carbon atom, in that the effects of the present invention can be further exhibited. 12 hydrocarbon groups, more preferably a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, and particularly preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

In the general formula (3), A ³ O is an oxyalkylene group having 2 to 18 carbon atoms, preferably an oxyalkylene group having 2 to 8 carbon atoms, more preferably 2 to 4 carbon atoms. It is an oxyalkylene group. When A ³ O is any two or more selected from oxyethylene group, oxypropylene group, oxybutylene group, oxystyrene group, etc., the addition form of A ³ O is random addition or block addition. Any form such as alternate addition may be used. In order to secure a balance between hydrophilicity and hydrophobicity, it is preferable that the oxyalkylene group contains an oxyethylene group as an essential component, and more than 50 mol% of the entire oxyalkylene group is an oxyethylene group. Preferably, 90 mol% or more of the entire oxyalkylene group is more preferably an oxyethylene group, and 100 mol% or more of the entire oxyalkylene group is particularly preferably an oxyethylene group. The oxyalkylene group may be one type or two or more types.

In the general formula (3), s represents an average addition mole number of the oxyalkylene group represented by A ³ O (sometimes referred to as “chain length”), and is 70 to 30,000, preferably 90 to 10,000. More preferably, it is 100-5000, More preferably, it is 200-3000, Especially preferably, it is 300-1000, Most preferably, it is 400-800. When s is within the above range, the cement admixture of the present invention can significantly improve the strength of the cured product of the cement composition over a long period of time.

  The mass average molecular weight (Mw) of the polyalkylene glycol (A4) is preferably 3000 or more, more preferably 4,000 to 1,000,000, further preferably 5,000 to 500,000, particularly preferably 10,000 to 300,000, Preferably it is 30000-200000. When the mass average molecular weight (Mw) of the polyalkylene glycol (A4) is within the above range, the cement admixture of the present invention can significantly improve the strength of the cured product of the cement composition over a long period of time.

  Examples of the polyalkylene glycol (A4) represented by the general formula (3) include polyethylene glycol and polypropylene glycol.

≪Alkanolamine compound (B) ≫
Any appropriate alkanolamine compound can be adopted as the alkanolamine compound (B) as long as the effects of the present invention are not impaired. Examples of such alkanolamine compounds include low molecular alkanolamine compounds and high molecular alkanolamine compounds.

  Examples of the low molecular alkanolamine compound include monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, methylethanolamine, methylisopropanolamine, methyldiethanolamine, methyldiisopropanolamine, Diethanolisopropanolamine, diisopropanolethanolamine, tetrahydroxyethylethylenediamine, N, N-bis (2-hydroxyethyl) 2-propanolamine, N, N-bis (2-hydroxypropyl) -N- (hydroxyethyl) amine, N, N-bis (2-hydroxyethyl) -N- (2-hydroxypropyl) amine, N, N, N ′, N′-tetrakis (2- Mud hydroxypropyl) ethylenediamine, tris (2-hydroxybutyl) amine, and the like. Among these, the low molecular alkanolamine compound is preferably triisopropanolamine, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, or diisopropanolethanolamine. Other low molecular alkanolamine compounds include, for example, monomers having a triisopropanolamine skeleton.

  Examples of the polymer type alkanolamine compound include alkanolamines having a structure in which a part of alkanolamine is bonded to a polymer. Examples of such a high molecular alkanolamine compound include a polymer having a triisopropanolamine skeleton.

≪Dispersant (C) ≫
Dispersant (C)
(V) a combination (C1) of two or more different polycarboxylic acid dispersants (Ca),
(Vi) a combination (C2) of at least one polycarboxylic acid dispersant (Ca) and at least one polycarboxylic acid dispersant (Cb);
Is at least one selected from

  In the cement admixture of the present invention, the dispersant (C) can contribute to the improvement of the dispersibility and flow retention of the cement composition.

<Dispersant (C1)>
The dispersant (C1) is a combination of two or more different polycarboxylic acid dispersants (Ca). By setting it as such a combination, the cement admixture of this invention can contribute by the improvement of the dispersibility of a cement composition, and a fluid holding | maintenance property.

  As the content ratios of the two or more different polycarboxylic acid-based dispersants (C-a) contained in the dispersant (C1), any appropriate content ratio is adopted as long as the effects of the present invention are not impaired. obtain. Such a content is preferably 0.001% by mass to 99.999% by mass, more preferably 0.01% by mass to 99.99% by mass, and still more preferably 0.1% by mass. % To 99.9% by mass, particularly preferably 1% to 99% by mass.

The polycarboxylic acid dispersant (Ca) is a structural unit derived from an unsaturated polyalkylene glycol ether monomer (a) represented by the general formula (1): YO (A ¹ O) _m R ⁰ ( It is a polycarboxylic acid copolymer having I) and a structural unit (IV) derived from an unsaturated carboxylic acid monomer (d). When the polycarboxylic acid-based dispersant (C-a) has such a structure, the cement admixture of the present invention can contribute to the improvement of the dispersibility and flow retention of the cement composition.

“A combination of two or more different polycarboxylic acid-based dispersants (Ca)” is a combination of two or more polycarboxylic acid-based dispersants (Ca) that are not the same. Specifically, for example,
-When Y in general formula (1) is different-When A ¹ O in general formula (1) is different-When m in general formula (1) is different-When R ⁰ in general formula (1) is different-Unsaturated When the carboxylic acid monomer (d) is different ・ When other monomers (e) described later are different ・ Structural unit (I) with respect to all structural units constituting the polycarboxylic acid dispersant (C-a) -When the content ratio of the structural unit (IV) is different from the total structural units constituting the polycarboxylic acid dispersant (C-a)-Construct the polycarboxylic acid dispersant (C-a) Selected from the cases where the content ratio of structural units other than the structural unit (I) and the structural unit (IV) (structural units (V) derived from other monomers (e) to be described later) other than the structural unit (I) is different. There may be at least one case.

  In the polycarboxylic acid-based dispersant (Ca), the content ratio of the structural unit having a carboxyl group or a salt thereof is preferably 20 mol% or more, preferably 25 mol%, based on all structural units constituting the polycarboxylic acid-based dispersant. It is -90 mol%, More preferably, it is 25 mol%-85 mol%, More preferably, it is 30 mol%-80 mol%, Most preferably, it is 35 mol%-75 mol%. The cement admixture of the present invention is a cement composition because the content ratio of the structural unit having a carboxyl group or a salt thereof with respect to all the structural units constituting the polycarboxylic acid-based dispersant (Ca) is within the above range. Can be remarkably improved. The “carboxyl group or a salt thereof” herein is a group represented by —COOM, and M is a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group. .

The structural unit (I) derived from the unsaturated polyalkylene glycol ether monomer (a) represented by the general formula (1): YO (A ¹ O) _m R ⁰ is specifically represented by the general formula ( 1) A structural unit in which the unsaturated double bond (C═C) of Y in the unsaturated polyalkylene glycol ether monomer (a) represented is converted to —C—C— by a polymerization reaction.

Regarding the structural unit (I) derived from the unsaturated polyalkylene glycol ether monomer (a) represented by the general formula (1): YO (A ¹ O) _m R ⁰ , <Copolymer (A1)> The description in the section can be incorporated.

The unsaturated carboxylic acid monomer (d) is represented by the general formula (4).

The structural unit (IV) derived from the unsaturated carboxylic acid monomer (d) represented by the general formula (4) is specifically represented by the following formula.

In the general formula (4) and the structural unit (IV), R ^{11 to} R ¹³ are the same or different and each represents a hydrogen atom, a methyl group, or a — (CH ₂ ) _z COOM group. The — (CH ₂ ) _z COOM group may form an anhydride with the —COOX group or other — (CH ₂ ) _z COOM groups. z is an integer of 0-2.

  M represents a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group.

  X represents a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group.

  Examples of the unsaturated carboxylic acid monomer (d) represented by the general formula (4) include monocarboxylic acid monomers such as (meth) acrylic acid and crotonic acid or salts thereof; maleic acid, And dicarboxylic acid monomers such as itaconic acid and fumaric acid or salts thereof; anhydrides of dicarboxylic acid monomers such as maleic acid, itaconic acid and fumaric acid or salts thereof; and the like. Examples of the salt herein include alkali metal salts, alkaline earth metal salts, ammonium salts, organic ammonium salts, and organic amine salts.

  Examples of the alkali metal salt include lithium salt, sodium salt, potassium salt and the like. Examples of alkaline earth metal salts include calcium salts and magnesium salts.

  Examples of the organic ammonium salt include methyl ammonium salt, ethyl ammonium salt, dimethyl ammonium salt, diethyl ammonium salt, trimethyl ammonium salt, and triethyl ammonium salt.

  Examples of the organic amine salt include ethanolamine salt, diethanolamine salt, triethanolamine salt, monoisopropanolamine salt, diisopropanolamine salt, triisopropanolamine salt, hydroxyethyldiisopropanolamine salt, dihydroxyethylisopropanolamine salt, tetrakis ( And alkanolamine salts such as 2-hydroxypropyl) ethylenediamine and pentakis (2-hydroxypropyl) diethylenetriamine. Among these, preferred are diisopropanolamine salt, triisopropanolamine salt, hydroxyethyldiisopropanolamine salt, tetrakis (2-hydroxypropyl) ethylenediamine salt, pentakis (2-hydroxypropyl) diethylenetriamine salt, more preferably Triisopropanolamine salt, hydroxyethyl diisopropanolamine salt.

  The unsaturated carboxylic acid monomer (d) represented by the general formula (4) is preferably (meth) acrylic acid, maleic acid, maleic anhydride in that the effect of the present invention can be further exhibited. More preferred are acrylic acid and maleic acid.

  The unsaturated carboxylic acid monomer (d) represented by the general formula (4) may be only one kind or two or more kinds.

  The total content of the structural unit (I) and the structural unit (IV) in the polycarboxylic acid-based dispersant (Ca) is a main component in the structural units constituting the copolymer. It is preferably 51% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, still more preferably 90% by mass to 100% by mass, and particularly preferably 95% by mass to 100% by weight, most preferably substantially 100% by weight. Since the total content ratio of the structural unit (I) and the structural unit (IV) in the polycarboxylic acid-based dispersant (Ca) is within the above range, the cement admixture of the present invention can be used as a cement composition. It can contribute by improving dispersibility and fluidity retention.

  In the polycarboxylic acid dispersant (Ca), in addition to the structural unit (I) and the structural unit (IV), the structural unit (III) derived from the hydroxyalkyl ester (c) of unsaturated carboxylic acid, unsaturated Either the structural unit (VI) derived from the polyalkylene glycol ester monomer (f) or the structural unit (V) derived from another monomer (e) may be included. Specific examples of each monomer are as described above or below.

  The other monomer (e) is a monomer copolymerizable with the monomer (a), the monomer (c), the monomer (d), and the monomer (f). Only one type of other monomer (e) may be used, or two or more types may be used.

  The content ratio of each structural unit in the polycarboxylic acid-based dispersant (C-a) can be known, for example, by various structural analyzes (for example, NMR) of the polycarboxylic acid-based dispersant (C-a). . Further, without performing the above-described various structural analyses, the unit calculated based on the amount of each monomer used and the polymerization rate used in the production of the polycarboxylic acid-based dispersant (Ca) can be calculated. It is good also as a content rate of each structural unit in a polycarboxylic acid type dispersing agent (Ca) with the content rate of the structural unit derived from a monomer.

  The content ratio of the structural unit (I) in the polycarboxylic acid dispersant (Ca) is preferably the main component in the structural unit constituting the copolymer, preferably 60% by mass. To 99% by mass, more preferably 65% to 97% by mass, still more preferably 70% to 95% by mass, particularly preferably 75% to 90% by mass, and most preferably 80%. It is mass%-85 mass%.

The content ratio of the structural unit (IV) in the polycarboxylic acid-based dispersant (Ca) is preferably 1% by mass to 40% by mass, more preferably 3% by mass to 35% by mass, and still more preferably. Is 5% by mass to 30% by mass, particularly preferably 10% by mass to 25% by mass.
It is good also as a content rate of structural unit (IV) in a boronic acid type dispersing agent (Ca).

  When the content ratio of the structural unit in the polycarboxylic acid dispersant (C-a) is obtained, if the structural unit has a carboxyl group, it is calculated as a completely neutralized (sodium salt). I do.

  The mass average molecular weight (Mw) of the polycarboxylic acid-based dispersant (C-a) is preferably 1000 or more, more preferably 3000 to 500,000, still more preferably 5000 to 300000, and still more preferably 10,000 to It is 250,000, More preferably, it is 20000-200000, Especially preferably, it is 30000-150,000, Most preferably, it is 40000-100,000. When the mass average molecular weight (Mw) of the polycarboxylic acid dispersant (Ca) is within the above range, the cement admixture of the present invention can contribute to the improvement of the dispersibility of the cement composition, and the cement. The strength of the cured product of the composition can be significantly improved over a long period of time.

  The polycarboxylic acid dispersant (C-a) can be produced by any appropriate method as long as the effects of the present invention are not impaired. Preferably, the method for producing the polycarboxylic acid copolymer (A1) described above can be used as the method for producing the polycarboxylic acid dispersant (C-a).

<Dispersant (C2)>
The dispersant (C2) is a combination of one or more polycarboxylic acid dispersants (Ca) and one or more polycarboxylic acid dispersants (Cb). By setting it as such a combination, the cement admixture of this invention can contribute by the improvement of the dispersibility of a cement composition, and a fluid holding | maintenance property.

  The respective content ratios of one or more of the polycarboxylic acid dispersant (Ca) and one or more of the polycarboxylic acid dispersant (Cb) contained in the dispersant (C2) are as follows. Any appropriate content ratio can be adopted as long as the effect is not impaired. Such a content is preferably 0.001% by mass to 99.999% by mass, more preferably 0.01% by mass to 99.99% by mass, and still more preferably 0.1% by mass. % To 99.9% by mass, particularly preferably 1% to 99% by mass.

  One or more of the polycarboxylic acid-based dispersant (C-a) means “polycarboxylic acid-based dispersant (C-a) (one type thereof)” or “polycarboxylic acid-based dispersant (C-a)”. 2 or more different types ". Regarding “polycarboxylic acid-based dispersant (Ca) (one type)” and “two or more different types of polycarboxylic acid-based dispersant (Ca)”, the description in the section of <Dispersant (C1)> Can be used.

（一般式（５）中、Ｒ^１４およびＲ^１５は、同一または異なって、水素原子またはメチル基を表し、Ｒ^１６は、水素原子または炭素原子数１〜３０の炭化水素基を表し、Ａ^２Ｏは、炭素原子数２〜１８のオキシアルキレン基を表し、ｎは、Ａ^２Ｏで表されるオキシアルキレン基の平均付加モル数を表し、ｎは２〜３００である。） The polycarboxylic acid dispersant (Cb) is composed of the structural unit (VI) derived from the unsaturated polyalkylene glycol ester monomer (f) represented by the general formula (5) and the unsaturated monocarboxylic acid monomer. It is a copolymer having the structural unit (VII) derived from the monomer (g). When the polycarboxylic acid dispersant (Cb) has such a structure, the cement admixture of the present invention can contribute to the improvement of the dispersibility and flow retention of the cement composition.

(In the general formula ^{(5), R 14} and ^{R 15} are the same or different, represent a hydrogen atom or a methyl ^{group, R 16} represents a hydrogen atom or a hydrocarbon group having a carbon number of 1 to 30, ^{A 2} O represents an oxyalkylene group having 2 to 18 carbon atoms, n represents the average number of added moles of the oxyalkylene group represented by A ² O, and n is 2 to 300.)

（一般式（６）中、Ｒ^１７〜Ｒ^１９は、同一または異なって、水素原子またはメチル基を表し、Ｘは、水素原子、アルカリ金属、アルカリ土類金属、アンモニウム基、有機アンモニウム基、または有機アミン基を表す。） The unsaturated monocarboxylic acid monomer (g) is represented by the general formula (6).

(In General Formula (6), R ^{17 to} R ¹⁹ are the same or different and each represents a hydrogen atom or a methyl group, and X represents a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or Represents an organic amine group.)

  One or more of the polycarboxylic acid-based dispersant (Cb) is “polycarboxylic acid-based dispersant (Cb) (one type thereof)” or “polycarboxylic acid-based dispersant (Cb)”. 2 or more different types ".

“A combination of two or more different polycarboxylic acid-based dispersants (Cb)” is a combination of two or more polycarboxylic acid-based dispersants (Cb) that are not the same. Specifically, for example,
-When R ^{14 in} general formula (5) is different-When R ^{15 in} general formula (5) is different-When R ^{16 in} general formula (5) is different-When A ² O in general formula (5) is different- When n in general formula (5) is different ・ Unsaturated monocarboxylic acid monomer (g) is different ・ Other monomer (e) described later is different ・ Polycarboxylic acid dispersant (C- When the content ratio of the structural unit (VI) with respect to all the structural units constituting b) is different. When the content ratio of the structural unit (VII) with respect to all the structural units constituting the polycarboxylic acid dispersant (Cb) is different. -Structural units other than structural unit (VI) and structural unit (VII) with respect to all structural units constituting polycarboxylic acid dispersant (Cb) (structural units derived from other monomer (e) described later) (V) etc.) It includes the case of at least one selected from vary.

  In the polycarboxylic acid-based dispersant (Cb), the content ratio of the structural unit having a carboxyl group or a salt thereof is preferably 20 mol% or more, preferably 25 mol%, based on all the structural units constituting the polycarboxylic acid dispersant (Cb). It is -90 mol%, More preferably, it is 25 mol%-85 mol%, More preferably, it is 30 mol%-80 mol%, Most preferably, it is 35 mol%-75 mol%. The cement admixture of the present invention is a cement composition because the content ratio of the structural unit having a carboxyl group or a salt thereof to the total structural units constituting the polycarboxylic acid dispersant (Cb) is within the above range. The dispersibility and fluidity of the fluid can be significantly improved. The “carboxyl group or a salt thereof” herein is a group represented by —COOM, and M is a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group. .

The structural unit (VI) derived from the unsaturated polyalkylene glycol ester monomer (f) represented by the general formula (5) is specifically represented by the following formula.

The structural unit (VII) derived from the unsaturated monocarboxylic acid monomer (g) represented by the general formula (6) is specifically represented by the following formula.

In the general formula (5) and the structural unit (VI), R ¹⁴ and R ¹⁵ are the same or different and each represents a hydrogen atom or a methyl group.

In the general formula (5) and the structural unit (VI), R ¹⁶ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. Examples of the hydrocarbon group having 1 to 30 carbon atoms include an alkyl group having 1 to 30 carbon atoms (an aliphatic alkyl group and an alicyclic alkyl group), an alkenyl group having 1 to 30 carbon atoms, and the number of carbon atoms. Examples thereof include an alkynyl group having 1 to 30 carbon atoms and an aromatic group having 6 to 30 carbon atoms. R ³ is preferably a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and more preferably a hydrogen atom or a carbon atom having 1 to 12 carbon atoms in that the effects of the present invention can be further exhibited. It is a hydrogen group, more preferably a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, and particularly preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

In general formula (5) and structural unit (VI), A ² O is an oxyalkylene group having 2 to 18 carbon atoms, preferably an oxyalkylene group having 2 to 8 carbon atoms, more preferably carbon. It is an oxyalkylene group having 2 to 4 atoms. When A ² O is any two or more selected from oxyethylene group, oxypropylene group, oxybutylene group, oxystyrene group, etc., the addition form of A ² O is random addition or block addition. Any form such as alternate addition may be used. In order to secure a balance between hydrophilicity and hydrophobicity, it is preferable that the oxyalkylene group contains an oxyethylene group as an essential component, and more than 50 mol% of the entire oxyalkylene group is an oxyethylene group. Preferably, 90 mol% or more of the entire oxyalkylene group is more preferably an oxyethylene group, and 100 mol% or more of the entire oxyalkylene group is particularly preferably an oxyethylene group. The oxyalkylene group may be one type or two or more types.

In the general formula (5) and the structural unit (VI), n represents the average added mole number of the oxyalkylene group represented by A ² O (sometimes referred to as “chain length”), and is 2 to 300. , Preferably it is 5-150, More preferably, it is 10-100, More preferably, it is 15-75, Most preferably, it is 20-50. When n is in the above range, the cement admixture of the present invention can contribute to the improvement of the dispersibility of the cement composition, and can remarkably improve the strength of the cured product of the cement composition over a long period of time.

  As the unsaturated polyalkylene glycol ester monomer (f) represented by the general formula (5), for example, an alkylene oxide having 2 to 18 carbon atoms is added to a saturated aliphatic alcohol having 1 to 20 carbon atoms. Esterified products of alkoxypolyalkylene glycols and (meth) acrylic acid or crotonic acid obtained as above; unsaturated fatty alcohols having 3 to 20 carbon atoms such as (meth) allyl alcohol, crotyl alcohol, oleyl alcohol, etc. An ester of an alkoxypolyalkylene glycol obtained by adding an alkylene oxide having 2 to 18 carbon atoms to (meth) acrylic acid or crotonic acid; an alicyclic group having 3 to 20 carbon atoms such as cyclohexanol By adding alkylene oxides having 2 to 18 carbon atoms to alcohols Esterified products of alkoxypolyalkylene glycols and (meth) acrylic acid or crotonic acid; alkoxypolyalkyls obtained by adding alkylene oxides having 2 to 18 carbon atoms to aromatic alcohols having 6 to 20 carbon atoms And esterified products of alkylene glycols with (meth) acrylic acid or crotonic acid.

  The unsaturated polyalkylene glycol ester monomer (f) represented by the general formula (5) is preferably an alkoxy polyalkylene glycol of (meth) acrylic acid from the viewpoint that the effects of the present invention can be further exhibited. A kind of ester.

  The unsaturated polyalkylene glycol ester monomer (f) represented by the general formula (5) may be only one type or two or more types.

In the general formula (6) and the structural unit (VII), R ^{17 to} R ¹⁹ are the same or different and each represents a hydrogen atom or a methyl group.

  X represents a hydrogen atom, a monovalent metal atom, a divalent metal atom, an ammonium group, an organic ammonium group, or an organic amine group.

  Examples of the unsaturated monocarboxylic acid monomer (g) represented by the general formula (6) include (meth) acrylic acid, crotonic acid, and salts thereof. Examples of the salt herein include alkali metal salts, alkaline earth metal salts, ammonium salts, organic ammonium salts, and organic amine salts. Examples of the alkali metal salt include lithium salt, sodium salt, potassium salt and the like. Examples of alkaline earth metal salts include calcium salts and magnesium salts. Examples of the organic ammonium salt include methyl ammonium salt, ethyl ammonium salt, dimethyl ammonium salt, diethyl ammonium salt, trimethyl ammonium salt, and triethyl ammonium salt. Examples of organic amine salts include ethanolamine salts, diethanolamine salts, triethanolamine salts, alkanolamine salts such as triisopropanolamine salts, and the like.

  The unsaturated monocarboxylic acid monomer (g) represented by the general formula (6) is preferably (meth) acrylic acid in that the effect of the present invention can be further exhibited.

  The unsaturated monocarboxylic acid monomer (g) represented by the general formula (6) may be only one type or two or more types.

  The total content of the structural unit (VI) and the structural unit (VII) in the polycarboxylic acid-based dispersant (Cb) is such that it is a main component in the structural units constituting the copolymer. It is preferably 51% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, still more preferably 90% by mass to 100% by mass, and particularly preferably 95% by mass to 100% by weight, most preferably substantially 100% by weight. When the total content of the structural unit (I) and the structural unit (II) in the polycarboxylic acid-based copolymer (A1) is within the above range, the cement admixture of the present invention can be used as a cement composition. It can contribute by improving dispersibility and fluidity retention.

  In the polycarboxylic acid type dispersant (Cb), in addition to the structural unit (VI) and the structural unit (VII), the structural unit (I) derived from the unsaturated polyalkylene glycol ether monomer (a), Either a structural unit (III) derived from a hydroxyalkyl ester (c) of an unsaturated carboxylic acid or a structural unit (V) derived from another monomer (e) may be contained. Specific examples of each monomer are as described above or below.

  The other monomer (e) is a monomer copolymerizable with the monomer (a), the monomer (c), the monomer (f), and the monomer (g). Only one type of other monomer (e) may be used, or two or more types may be used.

  The content ratio of each structural unit in the polycarboxylic acid dispersant (Cb) can be known, for example, by various structural analyzes (for example, NMR) of the polycarboxylic acid dispersant (Cb). . Further, without performing the above various structural analyses, the single unit is calculated based on the amount of each monomer used and the polymerization rate used in the production of the polycarboxylic acid dispersant (Cb). It is good also as a content rate of each structural unit in a polycarboxylic acid type dispersing agent (Cb) with the content rate of the structural unit derived from a monomer.

  The content ratio of the structural unit (VI) in the polycarboxylic acid dispersant (Cb) is preferably 60% by mass to 99% by mass, more preferably 65% by mass to 97% by mass, and still more preferably. Is 70% by mass to 95% by mass, particularly preferably 75% by mass to 90% by mass, and most preferably 80% by mass to 85% by mass.

  The content ratio of the structural unit (VII) in the polycarboxylic acid dispersant (Cb) is preferably 1% by mass to 40% by mass, more preferably 3% by mass to 35% by mass, and still more preferably. Is 5% by mass to 30% by mass, particularly preferably 10% by mass to 25% by mass.

  When determining the content ratio of the structural unit in the polycarboxylic acid dispersant (Cb), if the structural unit has a carboxyl group, it is calculated as a completely neutralized (sodium salt). I do.

  The mass average molecular weight (Mw) of the polycarboxylic acid-based dispersant (Cb) is 1000 or more, preferably 3000 to 500000, more preferably 5000 to 300000, still more preferably 10,000 to 250,000, Especially preferably, it is 30000-150,000, Most preferably, it is 40000-100000. When the mass average molecular weight (Mw) of the polycarboxylic acid copolymer (A1) is within the above range, the cement admixture of the present invention can contribute to the improvement of the dispersibility of the cement composition, and the cement composition. The strength of the cured product can be significantly improved over a long period of time.

  The polycarboxylic acid-based dispersant (Cb) can be produced by any appropriate method as long as the effects of the present invention are not impaired. Preferably, the method for producing the copolymer (A1) described above can be used as the method for producing the polycarboxylic acid-based dispersant (Cb).

≪≪Cement composition≫≫
The cement composition of the present invention is a cement composition containing a polyoxyalkylene compound (A), an alkanolamine compound (B), a dispersant (C), and cement.

  The cement composition of the present invention preferably contains water and aggregate.

  Any appropriate aggregate such as fine aggregate (sand, etc.) or coarse aggregate (crushed stone, etc.) can be adopted as the aggregate. Examples of such aggregates include gravel, crushed stone, granulated slag, and recycled aggregate. Examples of such aggregates include refractory aggregates such as siliceous, clay, zircon, high alumina, silicon carbide, graphite, chromic, chromic, and magnesia.

  The cement composition of the present invention can contain any appropriate cement additive (material) as long as the effects of the present invention are not impaired. Examples of such cement additives (materials) include cement additives (materials) exemplified in the following (1) to (12). Arbitrary appropriate compounding quantities can be employ | adopted for the compounding quantity of a cement additive (material) according to the kind and purpose of the cement additive (material) to be used.

(1) Water-soluble polymer substances: nonionic cellulose ethers such as methylcellulose, ethylcellulose, carboxymethylcellulose; polysaccharides produced by microbial fermentation such as yeast glucan, xanthan gum, β-1.3 glucans; polyacrylamide, etc. .

(2) Polymer emulsion: Copolymers of various vinyl monomers such as alkyl (meth) acrylate.

(3) Curing retarder: oxycarboxylic acid or salt thereof such as gluconic acid, glucoheptonic acid, alabonic acid, malic acid, citric acid; sugar and sugar alcohol; polyhydric alcohol such as glycerin; aminotri (methylenephosphonic acid) Phosphonic acid and its derivatives.

  In addition, as a ratio of the hardening retarder with respect to a compound (A), Preferably they are 1 mass%-1000 mass%, More preferably, they are 2 mass%-700 mass%, More preferably, they are 5 mass%-500 mass%. Especially preferably, it is 10 mass%-300 mass%, Most preferably, it is 20 mass%-200 mass%.

(4) Early strengthening agents / accelerators: soluble calcium salts such as calcium chloride, calcium nitrite, calcium nitrate, calcium bromide and calcium iodide; chlorides such as iron chloride and magnesium chloride; sulfates; potassium hydroxide; Sodium hydroxide; carbonate; thiosulfate; formate such as formic acid and calcium formate; alumina cement; calcium aluminate silicate and the like.

(5) Oxyalkylene antifoaming agents: polyoxyalkylene alkyl ethers such as diethylene glycol heptyl ether; polyoxyalkylene acetylene ethers; (poly) oxyalkylene fatty acid esters; polyoxyalkylene sorbitan fatty acid esters; polyoxyalkylene alkyl (Aryl) ether sulfate ester salt; polyoxyalkylene alkyl phosphate ester; polyoxypropylene polyoxyethylene laurylamine (propylene oxide average 1-20 mol adduct, ethylene oxide average 1-20 mol adduct, etc.), alkylene oxide Polyoxya such as amines derived from fatty acids obtained from added cured beef tallow (propylene oxide average 1-20 mol adduct, ethylene oxide average 1-20 mol adduct, etc.) Sharp emission alkyl amines; polyoxyalkylene amide.

(6) Antifoaming agents other than oxyalkylene type: Mineral oil type, fat type, fatty acid type, fatty acid ester type, alcohol type, amide type, phosphate ester type, metal soap type, silicone type and the like.

(7) AE agent: resin soap, saturated or unsaturated fatty acid, sodium hydroxystearate, lauryl sulfate, ABS (alkylbenzene sulfonic acid), alkane sulfonate, polyoxyethylene alkyl (phenyl) ether, polyoxyethylene alkyl (phenyl) ether Sulfate ester or a salt thereof, polyoxyethylene alkyl (phenyl) ether phosphate ester or a salt thereof, protein material, alkenyl sulfosuccinic acid, α-olefin sulfonate and the like.

(8) Other surfactants: various anionic surfactants; various cationic surfactants such as alkyltrimethylammonium chloride; various nonionic surfactants; various amphoteric surfactants.

(9) Waterproofing agent: fatty acid (salt), fatty acid ester, oil and fat, silicone, paraffin, asphalt, wax and the like.

(10) Rust inhibitor: nitrite, phosphate, zinc oxide and the like.

(11) Crack reducing agent: polyoxyalkyl ether and the like.

(12) Expansion material: Ettlingite, coal, etc.

  Other known cement additives (materials) include cement wetting agents, thickeners, separation reducing agents, flocculants, drying shrinkage reducing agents, strength enhancers, self-leveling agents, colorants, fungicides, and the like. be able to. These known cement additives (materials) may be only one kind or two or more kinds.

  Arbitrary appropriate cement can be employ | adopted as a cement contained in the cement composition of this invention. Examples of such cements include Portland cement (ordinary, early strength, ultra-early strength, moderate heat, sulfate resistance and low alkali types thereof), various mixed cements (blast furnace cement, silica cement, fly ash cement), White Portland Cement, Alumina Cement, Super Fast Cement (1 Clinker Fast Cement, 2 Clinker Fast Cement, Magnesium Phosphate Cement), Grout Cement, Oil Well Cement, Low Exothermic Cement (Low Exothermic Blast Furnace Cement, Fly Ash Mix Low Exothermic blast furnace cement, belite high-content cement), ultra-high strength cement, cement-based solidified material, eco-cement (cement produced from one or more of municipal waste incineration ash and sewage sludge incineration ash). Furthermore, fine powders and gypsum such as blast furnace slag, fly ash, cinder ash, clinker ash, husk ash, silica powder, and limestone powder may be added to the cement composition of the present invention. The cement contained in the cement composition of the present invention may be only one type or two or more types.

In the cement composition of the present invention, any appropriate value can be set as the unit water amount per 1 m ³ , the amount of cement used, and the water / cement ratio. Such values, preferably, unit water is ^{100kg / m 3 ~185kg / m 3} , the amount of cement used is ^{250kg / m 3 ~800kg / m 3} , water / cement ratio (mass ratio) = is 0.1 to 0.7, more preferably, a unit water amount is ^{120kg / m 3 ~175kg / m 3} , the amount of cement used is ^{270kg / m 3 ~800kg / m 3} , water / cement ratio ( (Mass ratio) = 0.12 to 0.65. As described above, the cement composition of the present invention can be widely used from poor blending to rich blending, and can be used for both high-strength concrete with a large amount of unit cement and poor blended concrete with a unit cement amount of 300 kg / m ³ or less. It is valid.

  The cement composition of the present invention can be effective for ready-mixed concrete, concrete for concrete secondary products, concrete for centrifugal molding, concrete for vibration compaction, steam-cured concrete, shotcrete, and the like. The cement composition of the present invention includes medium-fluidity concrete (concrete with a slump value of 22 to 25 cm), high-fluidity concrete (concrete with a slump value of 25 cm or more and a slump flow value of 50 to 70 cm), self-filling concrete, self It can also be effective for mortar and concrete that require high fluidity, such as leveling materials.

  The cement composition of the present invention may be prepared by blending the constituent components by any appropriate method. For example, the method etc. which knead | mix a structural component in a mixer are mentioned.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples. Unless otherwise specified, the term “part” means mass part, and the term “%” means mass%.

<Mass average molecular weight analysis conditions>
Columns used: TSK guard column α + TSK gel α-5000 + TSK gel α-4000 + TSK gel α-3000, manufactured by Tosoh Corporation and used one by one.
Eluent: sodium dihydrogen phosphate · 2H ₂ O: 62.4 g, disodium hydrogen phosphate · 12H ₂ O: 143.3 g dissolved in ion-exchanged water: 774.3 g, acetonitrile: 2000 g A mixed solution was used.
Detector: Triple detector “Model 302 light scattering detector” manufactured by Viscotek, 90 ° scattering angle for right angle light scattering, 7 ° scattering angle for low angle light scattering, 18 μL for cell capacity, and 670 nm for wavelength.
Standard sample: Polyethylene glycol SE-8 (Mw = 107000) manufactured by Tosoh Corporation was used, its dn / dC was 0.135 ml / g, and the refractive index of the eluent was determined to be 1.333 to determine the apparatus constant.
-Injection amount standard sample: 100 μL of the solution dissolved in the eluent so as to have a polymer concentration of 0.2 vol% was injected.
Sample: 100 μL of a solution dissolved in the eluent so that the polymer concentration was 1.0 vol% was injected.
・ Flow rate: 0.8ml / min
-Column temperature: 40 ° C

<Concrete test>
Ordinary Portland cement (manufactured by Taiheiyo Cement) as cement, Oikawa water-based land sand as fine aggregate, Qinghai crushed stone as coarse aggregate, tap water as kneaded water, cement: 320 kg / m ³ , water: 170 kg / m ³ , fine aggregate: 847 kg / m ³ , coarse aggregate: 942 kg / m ³ , fine aggregate ratio (fine aggregate / fine coarse aggregate + coarse aggregate) (volume ratio): 48%, water / cement ratio A concrete composition was prepared with a composition of (mass ratio) = 0.53. In addition, the temperature of the material used for the test, the forced kneading mixer, and the measuring instruments are adjusted in the above test temperature atmosphere so that the temperature of the concrete composition becomes 20 ° C. The kneading and each measurement are performed as described above. The test was performed under an atmosphere of test temperature. Also, in order to avoid the influence of air bubbles in the concrete composition on the fluidity of the concrete composition, an air amount adjusting agent is used as necessary to adjust the air amount to 1.0 ± 0.5%. did.
Concrete was produced in a kneading time of 90 seconds using a forced kneading mixer under the above conditions, and the slump value and the amount of air were measured. The slump value and the amount of air were measured in accordance with Japanese Industrial Standards (JIS-A-1101, 1128). The amount of the cement admixture added was such that the slump value was 8 to 15 cm.

<Measurement of compressive strength>
After kneading, the flow value and the amount of air were measured to prepare a sample for compressive strength test, and the compressive strength after 28 days was measured under the following conditions.
Specimen creation: 100mm x 200mm
Specimen curing (28 days): Temperature of about 20 ° C, humidity 60%, constant temperature and humidity air curing for 24 hours, then curing the specimen in water for 27 days: Specimen surface polishing (use of specimen polishing finish machine)
Compressive strength measurement: Automatic compressive strength meter (Maekawa Seisakusho)

[Production Example A-1]
A glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen introduction tube and a reflux condenser was charged with 103.7 g of ion-exchanged water, and the reactor was purged with nitrogen under stirring, and the temperature was raised to 70 ° C. . Next, a mixture comprising 144.0 g of an unsaturated polyalkylene glycol ether obtained by adding an average of 50 moles of ethylene oxide to 3-methyl-3-buten-1-ol, 16.0 g of 2-hydroxyethyl acrylate, and 80.0 g of ion-exchanged water. The solution was added dropwise over 4 hours. At the same time, an aqueous solution prepared by dissolving 1.98 g of ammonium persulfate in 64.05 g of ion-exchanged water and 0.06 g of 3-mercaptopropionic acid in 40.2 g of ion-exchanged water was added dropwise over 5 hours. After completion of the dropping, stirring was continued at 70 ° C. for 1 hour to complete the polymerization reaction, and an aqueous solution of a polycarboxylic acid copolymer having a mass average molecular weight (Mw) of 350,000 was obtained. The polymerization rate of the ethylene oxide adduct of 3-methyl-3-buten-1-ol was 80%, and the polymerization rate of hydroxyethyl acrylate was 99%. Sodium hydroxide aqueous solution was added to the obtained copolymer aqueous solution, and it neutralized to pH7. In this way, an aqueous solution of the copolymer (A-1) was obtained. From the polymerization rate of each raw material monomer, the copolymer composition ratio of the copolymer (A-1) was calculated. Specifically, from the polymerization rate of 80% with respect to 144 g of the amount of ethylene oxide adduct of 3-methyl-3-buten-1-ol and the polymerization rate of 99% with respect to 16 g of hydroxyethyl acrylate, 3-methyl-3-butene of the polymer was obtained. The ethylene oxide adduct content ratio of -1-ol can be calculated as 144 × 0.80 / (144 × 0.80 + 16 × 0.99) = 88%. Table 1 shows the copolymer composition ratio (mass%), copolymer composition ratio (mol%), and mass average molecular weight of the obtained polymer (A-1).

[Production Example A-3]
A glass reactor equipped with a Dimroth condenser, a Teflon (registered trademark) stirrer and a stirrer with a stirring seal, a nitrogen introduction tube, and a temperature sensor was charged with 80.0 g of ion-exchanged water, and nitrogen was stirred at 250 rpm. Was heated to 70 ° C. while being introduced at 200 mL / min. Next, from 160.0 g of ethylene oxide added to methacrylic acid (average number of moles of ethylene oxide added 8: PE350, manufactured by NOF Corporation), 3.87 g of 3-mercaptopropionic acid, and 106.7 g of ion-exchanged water Then, a mixed solution consisting of 0.749 g of ammonium persulfate and 48.71 g of ion-exchanged water was added dropwise over 5 hours. After completion of the dropwise addition, the polymerization reaction was completed by maintaining at 70 ° C. for 1 hour. And it neutralized with sodium hydroxide aqueous solution, and obtained the aqueous solution of the polymer (A-3) whose mass mean molecular weight (Mw) is 20000.

[Production Examples A-2, A-4, A-5]
A copolymerization reaction was carried out according to the method described in JP-T-2004-519406, and the copolymer composition ratios and mass-average molecular weight copolymers A-2, A-4, and A-5 as described in Table 1 were used. An aqueous solution was obtained.

[Production Example C-1]
An average of 50 mol of ethylene oxide was added to 85.5 g of ion-exchanged water and 3-methyl-3-buten-1-ol in a glass reaction vessel equipped with a thermometer, stirrer, dropping funnel, nitrogen inlet tube and reflux condenser. 139.4 g of the unsaturated polyalkylene glycol ether prepared was charged, and the reaction apparatus was purged with nitrogen under stirring, and the temperature was raised to 60 ° C. Next, an aqueous solution obtained by diluting 10.57 g of acrylic acid with 15.85 g of ion-exchanged water was dropped over 4 hours. At the same time, an aqueous solution in which 0.47 g of ammonium persulfate was dissolved in 11.37 g of ion-exchanged water and 0.18 g of 3-mercaptopropionic acid and 0.44 g of L-ascorbic acid was dissolved in 36.2 g of ion-exchanged water over 5 hours. It was dripped. After completion of the dropping, stirring was continued at 60 ° C. for 1 hour to complete the polymerization reaction, and an aqueous solution of a polycarboxylic acid copolymer having a mass average molecular weight (Mn) of 33000 was obtained. The polymerization rate of the ethylene oxide adduct of 3-methyl-3-buten-1-ol was 88%, and the polymerization rate of acrylic acid was 99%. A sodium hydroxide aqueous solution was added to the obtained polycarboxylic acid copolymer aqueous solution to neutralize to pH 7. In this way, a polycarboxylic acid-based dispersant (C-1) was obtained. From the polymerization rate of each raw material, the copolymer composition ratio of the copolymer (C-1) was calculated. Specifically, from the polymerization rate of 88% with respect to the use amount of 13methyl g of 3-methyl-3-buten-1-ol and the polymerization rate of 99% with respect to 10.57 g of acrylic acid, the polymer 3-methyl- The ethylene oxide adduct content ratio of 3-buten-1-ol can be calculated as 139.4 × 0.88 / (139.4 × 0.88 + 10.57 × 0.99 × 94/72) = 90%. (Acrylic acid is in terms of sodium salt) Table 2 shows the copolymer composition ratio (mass%), copolymer composition ratio (mol%), and mass average molecular weight of the obtained polymer (C-1).

[Production Examples C-2 to C-5, D-1 to D-4, F-1]
A copolymerization reaction is carried out according to the method described in JP-T-2004-519406, and copolymers C-2 to C-5 and D-1 having copolymer composition ratios and mass average molecular weights as described in Table 2 are used. An aqueous solution of D-4 and F-1 was obtained.

[Example 1]
PEG 20000 (polyethylene glycol, manufactured by Aldrich, mass average molecular weight = 20000) as the polyoxyalkylene compound (A), EDIPA (hydroxyethyldiisopropanolamine, manufactured by Aldrich) as the alkanolamine compound (B), and dispersant (C) A cement admixture (1) was prepared by blending as shown in Table 3 using the polycarboxylic acid dispersant (C-1) and the polycarboxylic acid dispersant (D-1). The results are shown in Table 3.

[Example 2]
The copolymer (A-1) as the polyoxyalkylene compound (A), and THEDA (N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, manufactured by Tokyo Chemical Industry Co., Ltd.) as the alkanolamine compound (B) Using a polycarboxylic acid dispersant (C-2) and a polycarboxylic acid dispersant (D-2) as a dispersant (C), blending as shown in Table 3 to prepare a cement admixture (2) did. The results are shown in Table 3.

Example 3
The copolymer (A-2) as the polyoxyalkylene compound (A), EDIPA (hydroxyethyldiisopropanolamine, manufactured by Aldrich) as the alkanolamine compound (B), and the polycarboxylic acid dispersant (as the dispersant (C)) A cement admixture (3) was prepared by blending as shown in Table 3 using C-3) and a polycarboxylic acid dispersant (D-2). The results are shown in Table 3.

Example 4
The copolymer (A-3) as the polyoxyalkylene compound (A), EDIPA (hydroxyethyldiisopropanolamine, manufactured by Aldrich) as the alkanolamine compound (B), and the polycarboxylic acid-based dispersant (as the dispersant (C)) A cement admixture (3) was prepared by blending as shown in Table 3 using C-4) and the polycarboxylic acid dispersant (D-1). The results are shown in Table 3.

Example 5
SB600 as a polyoxyalkylene compound (A) (mass average molecular weight = 26000, 1 mol of sorbitol added with an average of 600 mol of ethylene oxide), TIPA (triisopropanolamine, Wako Pure Chemical Industries, Ltd.) as an alkanolamine compound (B) Manufactured by Co., Ltd.), polycarboxylic acid-based dispersant (C-5), polycarboxylic acid-based dispersant (D-3), and polycarboxylic acid-based dispersant (F-1) as the dispersant (C). Table 3 Thus, a cement admixture (5) was prepared. The results are shown in Table 3.

Example 6
The copolymer (A-4) as the polyoxyalkylene compound (A), and THEDA (N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, manufactured by Tokyo Chemical Industry Co., Ltd.) as the alkanolamine compound (B) Using a polycarboxylic acid dispersant (C-4) and a polycarboxylic acid dispersant (D-1) as a dispersant (C), blending as shown in Table 3 to prepare a cement admixture (6) did. The results are shown in Table 3.

Example 7
PEG 20000 (polyethylene glycol, manufactured by Aldrich, mass average molecular weight = 20000) as the polyoxyalkylene compound (A), TIPA (triisopropanolamine, manufactured by Wako Pure Chemical Industries, Ltd.), dispersant (C) as the alkanolamine compound (B) A cement admixture (7) was prepared by blending as shown in Table 3 using a polycarboxylic acid dispersant (C-2) and a polycarboxylic acid dispersant (D-2). The results are shown in Table 3.

Example 8
The copolymer (A-5) as the polyoxyalkylene compound (A), EDIPA (hydroxyethyldiisopropanolamine, manufactured by Aldrich) as the alkanolamine compound (B), and the polycarboxylic acid-based dispersant (as the dispersant (C)) A cement admixture (8) was prepared by blending as shown in Table 3 using C-1) and a polycarboxylic acid-based dispersant (D-4). The results are shown in Table 3.

[Comparative Example 1]
As shown in Table 3, the polycarboxylic acid dispersant (C-1) was used as a cement admixture (C1). The results are shown in Table 3.

[Comparative Example 2]
As shown in Table 3, the polycarboxylic acid dispersant (C-3) was used as a cement admixture (C2). The results are shown in Table 3.

[Comparative Example 3]
As shown in Table 3, the polycarboxylic acid dispersant (C-1) and the polycarboxylic acid dispersant (D-1) were used as the cement admixture (C3). The results are shown in Table 3.

[Comparative Example 4]
As shown in Table 3, the polycarboxylic acid dispersant (C-3) and the polycarboxylic acid dispersant (D-2) were used as the cement admixture (C4). The results are shown in Table 3.

  As shown in Table 3, the cement compositions of Examples 1 to 8 were excellent in dispersibility and fluidity retention, and the 28-day compressive strength was remarkably excellent.

The cement admixture of the present invention is suitably used for cement compositions such as mortar and concrete.

Claims (2)

A cement admixture comprising a polyoxyalkylene compound (A), an alkanolamine compound (B) and a dispersant (C),
The polyoxyalkylene compound (A) is
(I) General formula (1): Unsaturated polyalkylene glycol ether monomer (a) represented by YO (A ¹ O) _m R ⁰ (in general formula (1), Y is 2 carbon atoms) Represents an alkenyl group having ˜8, R ⁰ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, A ¹ O represents an oxyalkylene group having 2 to 18 carbon atoms, and m represents A ¹ represents the average number of added moles of the oxyalkylene group represented by ¹ O, and m is 2 to 300.) derived from the structural unit (I) and the unsaturated amide monomer (b) (II) And / or a copolymer (A1) having a structural unit (III) derived from a hydroxyalkyl ester (c) of an unsaturated carboxylic acid,
(Ii) a polymer (A2) having a structural unit derived from an alkylene oxide adduct of an unsaturated carboxylic acid,
(Iii) an alkylene oxide adduct of a trihydric or higher polyhydric alcohol (A3),
(Iv) polyalkylene glycol (A4),
At least one selected from
The dispersant (C) is
(V) a combination (C1) of two or more different polycarboxylic acid dispersants (Ca),
(Vi) a combination (C2) of at least one polycarboxylic acid dispersant (Ca) and at least one polycarboxylic acid dispersant (Cb);
Is at least one selected from
Cement admixture.
The polycarboxylic acid dispersant (C-a) is an unsaturated polyalkylene glycol ether monomer (a) represented by the general formula (1): YO (A ¹ O) _m R ⁰ (general formula (1 ) Represents an alkenyl group having 2 to 8 carbon atoms, R ⁰ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and A ¹ O represents 2 to 18 carbon atoms. Represents an oxyalkylene group, m represents the average number of added moles of the oxyalkylene group represented by A ¹ O, and m is 2 to 300.) derived structural unit (I) It is a polycarboxylic acid copolymer having a structural unit (IV) derived from a monomer (d).
The polycarboxylic acid dispersant (Cb) is composed of the structural unit (VI) derived from the unsaturated polyalkylene glycol ester monomer (f) represented by the general formula (5) and the unsaturated monocarboxylic acid monomer. It is a copolymer having the structural unit (VII) derived from the monomer (g).

(In the general formula ^{(5), R 14} and ^{R 15} are the same or different, represent a hydrogen atom or a methyl ^{group, R 16} represents a hydrogen atom or a hydrocarbon group having a carbon number of 1 to 30, ^{A 2} O represents an oxyalkylene group having 2 to 18 carbon atoms, n represents the average number of added moles of the oxyalkylene group represented by A ² O, and n is 2 to 300.) A cement composition comprising a polyoxyalkylene compound (A), an alkanolamine compound (B), a dispersant (C) and cement,
The polyoxyalkylene compound (A) is
(I) General formula (1): Unsaturated polyalkylene glycol ether monomer (a) represented by YO (A ¹ O) _m R ⁰ (in general formula (1), Y is 2 carbon atoms) Represents an alkenyl group having ˜8, R ⁰ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, A ¹ O represents an oxyalkylene group having 2 to 18 carbon atoms, and m represents A ¹ represents the average number of added moles of the oxyalkylene group represented by ¹ O, and m is 2 to 300.) derived from the structural unit (I) and the unsaturated amide monomer (b) (II) And / or a copolymer (A1) having a structural unit (III) derived from a hydroxyalkyl ester (c) of an unsaturated carboxylic acid,
(Ii) a polymer (A2) having a structural unit derived from an alkylene oxide adduct of an unsaturated carboxylic acid,
(Iii) an alkylene oxide adduct of a trihydric or higher polyhydric alcohol (A3),
(Iv) polyalkylene glycol (A4),
At least one selected from
The dispersant (C) is
(V) a combination (C1) of two or more different polycarboxylic acid dispersants (Ca),
(Vi) a combination (C2) of at least one polycarboxylic acid dispersant (Ca) and at least one polycarboxylic acid dispersant (Cb);
Is at least one selected from
Cement composition.
The polycarboxylic acid dispersant (C-a) is an unsaturated polyalkylene glycol ether monomer (a) represented by the general formula (1): YO (A ¹ O) _m R ⁰ (general formula (1 ) Represents an alkenyl group having 2 to 8 carbon atoms, R ⁰ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and A ¹ O represents 2 to 18 carbon atoms. Represents an oxyalkylene group, m represents the average number of added moles of the oxyalkylene group represented by A ¹ O, and m is from 2 to 300.) derived from the structural unit (I) and the unsaturated carboxylic acid group It is a polycarboxylic acid copolymer having a structural unit (IV) derived from a monomer (d).
The polycarboxylic acid dispersant (Cb) is composed of the structural unit (VI) derived from the unsaturated polyalkylene glycol ester monomer (f) represented by the general formula (5) and the unsaturated monocarboxylic acid monomer. It is a copolymer having the structural unit (VII) derived from the monomer (g).

(In the general formula ^{(5), R 14} and ^{R 15} are the same or different, represent a hydrogen atom or a methyl ^{group, R 16} represents a hydrogen atom or a hydrocarbon group having a carbon number of 1 to 30, ^{A 2} O represents an oxyalkylene group having 2 to 18 carbon atoms, n represents the average number of added moles of the oxyalkylene group represented by A ² O, and n is 2 to 300.)