JP6864478B2 - Cement admixture and cement composition - Google Patents

Description

The present invention relates to cement admixtures and cement compositions.

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

Recently, there have been increasing demands 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 development of strength is desired, and various studies have been conducted (for example, Patent Document 1).

On the other hand, depending on the use of the cement composition, it is required to improve the strength of the cured product of the cement composition over a long period of time (for example, to improve the strength at the level of 4 weeks).

Japanese Unexamined Patent Publication No. 2011-84459

An object of the present invention is to provide a cement admixture capable of significantly improving the strength of a cured product of a cement composition over a long period of time. Another object of the present invention is to provide a cement composition in which the strength of a cured product can be remarkably improved over a long period of time.

（一般式（１）中、Ｒ^１およびＲ^２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^３は、炭素原子数１〜３０の炭化水素基を表し、Ａ^１Ｏは、炭素原子数２〜１８のオキシアルキレン基を表し、ｍは、Ａ^１Ｏ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、ｍは２〜３００である。） The cement admixture of the present invention
A cement admixture containing a polyoxyalkylene compound (A), an alkanolamine compound (B), and a dispersant (C).
The polyoxyalkylene compound (A)
(I) A structural unit (I) derived from an unsaturated polyalkylene glycol ester-based monomer (a) represented by the general formula (1) and a structural unit (I) derived from an unsaturated monocarboxylic acid-based monomer (b) ( A polypolymer having II), wherein the content ratio of the structural unit (II) to all the structural units constituting the copolymer is less than 37 mol%, and the mass average molecular weight is 3000 or more. Polycarboxylic acid-based copolymer (A1),
(Ii) An alkylene oxide adduct (A2) to active hydrogen bonded to the amino group of polyethyleneimine,
At least one selected from
The dispersant (C)
(Iii) General formula (3): YO (A ² O) _n R ⁰ is represented by an unsaturated polyalkylene glycol ether-based monomer (c) (in the general formula (3), Y has 2 carbon atoms. Represents an alkenyl group of ~ 4, R ⁰ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, A ² O represents an oxyalkylene group having 2 to 18 carbon atoms, and n is A. represents the average number of moles of the oxyalkylene group represented by ^{2 O,} n is 2 to 300.) structural units (III) with an unsaturated carboxylic acid monomer derived (d) structural units derived from ( Polycarboxylic acid-based dispersant (C1), which is a polycarboxylic acid-based copolymer having IV),
(Iv) Sulfonic acid-based dispersant (C2),
(V) Phosphoric acid-based dispersant (C3),
At least one selected from.

(In the general formula (1), R ¹ and R ² represent the same or different hydrogen atom or methyl group, R ³ represents a hydrocarbon group having 1 to 30 carbon atoms, and A ¹ O represents a hydrocarbon group. represents an oxyalkylene group having 2 to 18 carbon atoms, m represents an average addition mol number of the oxyalkylene group represented by ^{a 1} O, m is 2 to 300.)

（一般式（１）中、Ｒ^１およびＲ^２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^３は、炭素原子数１〜３０の炭化水素基を表し、Ａ^１Ｏは、炭素原子数２〜１８のオキシアルキレン基を表し、ｍは、Ａ^１Ｏ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、ｍは２〜３００である。） The cement composition of the present invention
A cement composition containing a polyoxyalkylene compound (A), an alkanolamine compound (B), a dispersant (C), and cement.
The polyoxyalkylene compound (A)
(I) A structural unit (I) derived from an unsaturated polyalkylene glycol ester-based monomer (a) represented by the general formula (1) and a structural unit (I) derived from an unsaturated monocarboxylic acid-based monomer (b) ( A polypolymer having II), wherein the content ratio of the structural unit (II) to all the structural units constituting the copolymer is less than 37 mol%, and the mass average molecular weight is 3000 or more. Polycarboxylic acid-based copolymer (A1),
(Ii) An alkylene oxide adduct (A2) to active hydrogen bonded to the amino group of polyethyleneimine,
At least one selected from
The dispersant (C)
(Iii) General formula (3): YO (A ² O) _n R ⁰ is represented by an unsaturated polyalkylene glycol ether-based monomer (c) (in the general formula (3), Y has 2 carbon atoms. Represents an alkenyl group of ~ 4, R ⁰ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, A ² O represents an oxyalkylene group having 2 to 18 carbon atoms, and n is A. represents the average number of moles of the oxyalkylene group represented by ^{2 O,} n is 2 to 300.) structural units (III) with an unsaturated carboxylic acid monomer derived (d) structural units derived from ( Polycarboxylic acid-based dispersant (C1), which is a polycarboxylic acid-based copolymer having IV),
(Iv) Sulfonic acid-based dispersant (C2),
(V) Phosphoric acid-based dispersant (C3),
At least one selected from.

(In the general formula (1), R ¹ and R ² represent the same or different hydrogen atom or methyl group, R ³ represents a hydrocarbon group having 1 to 30 carbon atoms, and A ¹ O represents a hydrocarbon group. represents an oxyalkylene group having 2 to 18 carbon atoms, m represents an average addition mol number of the oxyalkylene group represented by ^{a 1} O, m is 2 to 300.)

According to the present invention, it is possible to provide a cement admixture capable of significantly improving the strength of a cured product of a cement composition over a long period of time. Further, it is possible to provide a cement composition in which the strength of the cured product can be remarkably improved over a long period of time.

In the present specification, the expression "(meth) acrylic" means "acrylic and / or methacrolein", and the expression "(meth) acrylate" means "acrylate and / or methacrylate". When the expression "(meth) allyl" is used, it means "allyl and / or methacrolein", and when the expression "(meth) acrolein" is used, "acrolein and / or methacrolein" is used. It means "rain". In addition, when the expression "acid (salt)" is used in the present specification, it means "acid and / or a salt thereof".

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

The polyoxyalkylene compound (A) may be one kind or two or more kinds.

The alkanolamine compound (B) may be one kind or two or more kinds.

The dispersant (C) may be one kind or two or more kinds.

The cement admixture of the present invention can contribute to the improvement of the dispersibility of the cement composition by containing the polyoxyalkylene compound (A), the alkanolamine compound (B) and the dispersant (C), and the cement composition. It exerts the effect that the strength of the cured product can be remarkably improved over a long period of time.

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. It is preferably 70% by mass to 100% by mass, more preferably 90% by mass to 100% by mass, particularly preferably 95% by mass to 100% by mass, and most preferably substantially 100% by 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 can be mixed. The agent can contribute to the improvement of the dispersibility of the cement composition and can improve the strength of the cured product of the cement composition more remarkably 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 even more preferably. It is 3% by mass to 60% by mass, particularly preferably 5% by mass to 50% by mass, and most preferably 10% by mass to 40% by 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 remarkable 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. It 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 60% by mass, more preferably 0.5% by mass to 50% by mass, and further preferably. Is 1% by mass to 40% by mass, and particularly preferably 3% by mass to 30% 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. I can let you. When the content of the alkanolamine compound (B) in the cement admixture of the present invention is less than 0.2% by mass, it is difficult for the cement admixture of the present invention to improve the strength of the cured product of the cement composition over a long period of time. There is a risk.

The content ratio 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 35% by mass. It is 95% by mass, particularly preferably 40% by mass to 93% by mass, and most preferably 45% by mass to 90% 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 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 25% by mass, it may be difficult for the cement admixture of the present invention to 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 or more, based on the cement. It is 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. ~ 0.1% by 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 remarkable 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 the long term.

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, more preferably 0.005% by mass to 0, based on the cement. It is .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 0.02% by mass. It is 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. I can let you. 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 determines 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, and more preferably 0.03% by mass to 0.8% by mass with respect to the cement. %, More preferably 0.05% by mass to 0.6% by mass, particularly preferably 0.1% by mass to 0.5% by mass, and most preferably 0.15% by mass to 0.4. It is 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 more 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 is difficult to improve the dispersibility of the cement composition. There is a risk.

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, still more preferably 20% by mass to 200% by mass, and particularly preferably 30% by mass to 150% by mass. %, 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 is a cured product of the cement composition. The strength can be improved more significantly over the long term.

（一般式（１）中、Ｒ^１およびＲ^２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^３は、炭素原子数１〜３０の炭化水素基を表し、Ａ^１Ｏは、炭素原子数２〜１８のオキシアルキレン基を表し、ｍは、Ａ^１Ｏ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、ｍは２〜３００である。） << Polyoxyalkylene compound (A) >>
The polyoxyalkylene compound (A) is
(I) A structural unit (I) derived from an unsaturated polyalkylene glycol ester-based monomer (a) represented by the general formula (1) and a structural unit (I) derived from an unsaturated monocarboxylic acid-based monomer (b) ( A polypolymer having II), wherein the content ratio of the structural unit (II) to all the structural units constituting the copolymer is less than 37 mol%, and the mass average molecular weight is 3000 or more. Polycarboxylic acid-based copolymer (A1),
(Ii) An alkylene oxide adduct (A2) to active hydrogen bonded to the amino group of polyethyleneimine,
At least one selected from.

(In the general formula (1), R ¹ and R ² represent the same or different hydrogen atom or methyl group, R ³ represents a hydrocarbon group having 1 to 30 carbon atoms, and A ¹ O represents a hydrocarbon group. represents an oxyalkylene group having 2 to 18 carbon atoms, m represents an average addition mol number of the oxyalkylene group represented by ^{a 1} O, m is 2 to 300.)

（一般式（２）中、Ｒ^４〜Ｒ^６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-based monomer (b) is represented by the general formula (2).

(In the general formula (2), R ^{4 to} R ⁶ represent a hydrogen atom or a methyl group, which are the same or different, and X is a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or Represents an organic amine group.)

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

<Polycarboxylic acid copolymer (A1)>
The structural unit (I) derived from the unsaturated polyalkylene glycol ester-based monomer (a) represented by the general formula (1) is specifically represented by the following formula.

The structural unit (II) derived from the unsaturated monocarboxylic acid-based monomer (b) represented by the general formula (2) is specifically represented by the following formula.

In the general formula (1) and the structural unit (I), R ¹ and R ² represent the same or different hydrogen atoms or methyl groups.

In the general formula (1) and the structural unit (I), R ³ represents 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 (aliphatic alkyl group and alicyclic alkyl group), an alkenyl group having 1 to 30 carbon atoms, and a carbon atom number. Examples thereof include an alkynyl group of 1 to 30 and an aromatic group having 6 to 30 carbon atoms. A point capable of further exhibit the effect of the present invention, R ³ is preferably a hydrocarbon group having 1 to 20 carbon atoms, more preferably a hydrocarbon group having 1 to 12 carbon atoms, more A hydrocarbon group having 1 to 6 carbon atoms is preferable, and an alkyl group having 1 to 3 carbon atoms is particularly preferable.

In the general formula (1) and the structural unit (I), A ¹ O is an oxyalkylene group having 2 to 18 carbon atoms, preferably an oxyalkylene group having 2 to 8 carbon atoms, and more preferably carbon. It is an oxyalkylene group having 2 to 4 atoms. When A ¹ O is any two or more types selected from an oxyethylene group, an oxypropylene group, an oxybutylene group, an oxystyrene group, etc., ^{the addition form of A 1} O is random addition or block addition. , Alternate addition, etc. may be used. In order to secure a balance between hydrophilicity and hydrophobicity, it is preferable that the oxyethylene group contains an oxyethylene group as an essential component, and 50 mol% or more of the total oxyalkylene group is an oxyethylene group. It is more preferable that 90 mol% or more of the total oxyalkylene group is an oxyethylene group, and 100 mol% or more of the total oxyalkylene group is particularly preferably an oxyethylene group. The oxyalkylene group may be one kind or two or more kinds.

In the general formula (1) and the structural unit (I), m is a mean addition mol number of the oxyalkylene group represented by A 1 ^O (sometimes referred to as "chain length"), be 2-300 It is preferably 5 to 150, more preferably 10 to 100, still more preferably 15 to 75, and particularly preferably 20 to 50. When m is within the above range, the cement admixture of the present invention can improve the strength of the cured product of the cement composition more remarkably over a long period of time.

As the unsaturated polyalkylene glycol ester-based monomer (a) represented by the general formula (1), for example, an alkylene oxide having 2 to 18 carbon atoms is added to saturated aliphatic alcohols having 1 to 20 carbon atoms. A esterified product of alkoxypolyalkylene glycols obtained by the above and (meth) acrylic acid or crotonic acid; unsaturated aliphatic alcohols having 3 to 20 carbon atoms such as (meth) allyl alcohols, crotyl alcohols and oleyl alcohols. An esterified product of alkoxypolyalkylene glycols obtained by adding an alkylene oxide having 2 to 18 carbon atoms and (meth) acrylic acid or crotonic acid; an alicyclic having 3 to 20 carbon atoms such as cyclohexanol. An esterified product of an alkoxypolyalkylene glycol obtained by adding an alkylene oxide having 2 to 18 carbon atoms to a formula alcohol and (meth) acrylic acid or crotonic acid; aromatic alcohols having 6 to 20 carbon atoms. Examples thereof include an esterified product of an alkoxypolyalkylene glycol obtained by adding an alkylene oxide having 2 to 18 carbon atoms and (meth) acrylic acid or crotonic acid.

The unsaturated polyalkylene glycol ester-based monomer (a) represented by the general formula (1) is preferably an alkoxypolyalkylene glycol of (meth) acrylic acid in that the effects of the present invention can be further exhibited. It is a kind of ester.

The unsaturated polyalkylene glycol ester-based monomer (a) represented by the general formula (1) may be of only one type or of two or more types.

In the general formula (2) and the structural unit (II), R ^{4 to} R ⁶ represent the same or different hydrogen atoms or methyl groups.

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-based monomer (b) represented by the general formula (2) include (meth) acrylic acid, crotonic acid, and salts thereof. Examples of the salt referred to here 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 the alkaline earth metal salt include calcium salt and magnesium salt. Examples of the organic ammonium salt include methylammonium salt, ethylammonium salt, dimethylammonium salt, diethylammonium salt, trimethylammonium salt, triethylammonium salt and the like. Examples of the organic amine salt include alkanolamine salts such as ethanolamine salt, diethanolamine salt, triethanolamine salt, and triisopropanolamine salt.

The unsaturated monocarboxylic acid-based monomer (b) represented by the general formula (2) is preferably (meth) acrylic acid in that the effects of the present invention can be further exhibited.

The unsaturated monocarboxylic acid-based monomer (b) represented by the general formula (2) may be of only one type or of two or more types.

The total content ratio of the structural unit (I) and the structural unit (II) in the polycarboxylic acid-based copolymer (A1) is set to be the 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, further preferably 90% by mass to 100% by mass, and particularly preferably 95% by mass to 100% by mass. It is by mass, most preferably substantially 100% by mass. When the total content ratio 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 is a cement composition. The strength of the cured product can be significantly improved over a long period of time.

In the polycarboxylic acid-based copolymer (A1), in addition to the structural unit (I) and the structural unit (II), the structural unit (III) and the structure derived from the unsaturated polyalkylene glycol ether-based monomer (c) It may contain either a structural unit (IV) derived from an unsaturated carboxylic acid-based monomer (d) other than the unit (II) or a structural unit (V) derived from another monomer (e). The structural unit (IV) derived from the unsaturated carboxylic acid-based monomer (d) other than the structural unit (II) is derived from a dicarboxylic acid-based monomer such as maleic acid, itaconic acid, fumaric acid, or a salt thereof. Structural units; structural units derived from anhydrides of dicarboxylic acid-based monomers such as maleic acid, itaconic acid, fumaric acid, or salts thereof; and the like. Specific examples of the unsaturated polyalkylene glycol ether-based monomer (c) will be described later.

The other monomer (e) is a monomer copolymerizable with the monomer (a), the monomer (b), the monomer (c), and the monomer (d). The other monomer (e) may be only one kind or two or more kinds.

Examples of the other monomer (e) include hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate; and non-hydroxyalkyl (meth) acrylates such as methyl (meth) acrylate and glycidyl (meth) acrylate. Esters of saturated monocarboxylic acids and alcohols with 1 to 30 carbon atoms; Half esters of unsaturated dicarboxylic acids such as (anhydrous) maleic acid, fumaric acid, and itaconic acid with alcohols with 1 to 30 carbon atoms; Diesters of unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid and alcohols having 1 to 30 carbon atoms; halfamides of the unsaturated dicarboxylic acids and amines having 1 to 30 carbon atoms. Diamides of the unsaturated dicarboxylic acids and amines having 1 to 30 carbon atoms; alkyl (poly) alkylene glycols obtained by adding an average of 1 to 500 mol of alkylene oxides having 2 to 18 carbon atoms to the alcohols and amines. Half esters with the unsaturated dicarboxylic acids; Diesters of alkyl (poly) alkylene glycols with an average of 1 to 500 mol of alkylene oxides having 2 to 18 carbon atoms added to the alcohols and amines and the unsaturated dicarboxylic acids. Half esters of the unsaturated dicarboxylic acids and glycols having 2 to 18 carbon atoms or polyalkylene glycols having an average addition molar number of 2 to 500 of these glycols; Diesters with glycols or polyalkylene glycols with an average added molar number of 2 to 500 of these glycols; with maleamic acid and glycols with 2 to 18 carbon atoms or polyalkylene glycols with an average added molar number of 2 to 500 of these glycols. Halfamides; (poly) alkylene glycol di (meth) acrylates such as (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate; hexanediol di (meth) acrylate, trimethylol Polyfunctional (meth) acrylates such as propanetri (meth) acrylate; (poly) alkylene glycol dimalates such as polyethylene glycol dimalate; vinyl sulfonate, (meth) allyl sulfonate, 2-methylpropanesulfonic acid (meth) acrylamide , Unsaturated sulfonic acids (salts) such as styrene sulfonic acid; unsaturated monoca such as methyl (meth) acrylamide Amides of rubon acids and amines with 1 to 30 carbon atoms; vinyl aromatics such as styrene, α-methylstyrene and vinyltoluene; alkanediol mono (meth) such as 1,4-butanediol mono (meth) acrylate ) Esters; Dienes such as butadiene and isoprene; Unsaturated amides such as (meth) acrylic (alkyl) amides, N-methylol (meth) acrylamides, N, N-dimethyl (meth) acrylamides; (meth) acrylonitrile, etc. Unsaturated cyanes; unsaturated esters such as vinyl acetate; unsaturated amines such as (meth) aminoethyl acrylate, dimethylaminoethyl (meth) acrylate, vinylpyridine; divinyl aromatics such as divinylbenzene; Examples thereof include allyls such as (meth) allyl alcohol and glycidyl (meth) allyl ether;

The content ratio (sometimes referred to as “acid content”) of the structural unit (II) to all the structural units constituting the polycarboxylic acid-based copolymer (A1) is less than 37 mol%, preferably 0 mol%. It is ~ 35 mol%, more preferably 1 mol% ~ 33 mol%, further preferably 5 mol% ~ 30 mol%, and particularly preferably 10 mol% ~ 25 mol%. When the content ratio of the structural unit (II) to all the structural units constituting the polycarboxylic acid-based copolymer (A1) is within the above range, the cement admixture of the present invention is a cured product of the cement composition. The strength can be significantly improved over the long term.

The content ratio of each structural unit in the polycarboxylic acid-based copolymer (A1) can be known by, for example, various structural analyzes (for example, NMR) of the polycarboxylic acid-based copolymer (A1). Further, the single amount calculated based on the usage amount and the polymerization rate of each monomer used in producing the polycarboxylic acid-based copolymer (A1) without performing various structural analyzes as described above. The content ratio of the structural unit derived from the body may be used as the content ratio of each structural unit in the polycarboxylic acid-based copolymer (A1).

When determining the content ratio of structural units in the polycarboxylic acid-based copolymer (A1), if the structural unit has a carboxyl group, calculate it as a completely neutralized one (sodium salt). Do.

The mass average molecular weight (Mw) of the polycarboxylic acid-based copolymer (A1) is 3000 or more, preferably 4000 to 1000000, more preferably 5000 to 500000, still more preferably 1000 to 300000, and particularly. It is preferably 20000 to 250,000, and most preferably 30,000 to 200,000. When the mass average molecular weight (Mw) of the polycarboxylic acid-based 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 polycarboxylic acid-based copolymer (A1) can be produced by any suitable method as long as the effects of the present invention are not impaired. The polycarboxylic acid-based copolymer (A1) is preferably a polymerization of a monomer component containing an unsaturated polyalkylene glycol ester-based monomer (a) and an unsaturated monocarboxylic acid-based monomer (b). Can be produced in the presence of a polymerization initiator.

An unsaturated polyalkylene glycol ester-based monomer (a) that can be used in the production of the polycarboxylic acid-based copolymer (A1), an unsaturated monocarboxylic acid-based monomer (b), and, if necessary, non-saturated. Amount of saturated polyalkylene glycol ether-based monomer (c), unsaturated carboxylic acid-based monomer (d) other than unsaturated monocarboxylic acid-based monomer (b), and other monomer (e) used May be appropriately adjusted so that the ratio of the structural units derived from each monomer in the total structural units constituting the polycarboxylic acid-based copolymer (A1) is as described above.

The polymerization of the monomer component can be carried out by any suitable method. For example, solution polymerization and bulk polymerization can be mentioned. Examples of the solution polymerization method include batch type and continuous type. Solvents that can be used in 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; and 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, the polymerization initiator is a water-soluble polymerization initiator, for example, persulfate such as ammonium persulfate, sodium persulfate, potassium persulfate; hydrogen peroxide; 2,2'-. Azobisin compounds such as azobis-2-methylpropionamidine hydrochloride, cyclic azoamidin compounds such as 2,2'-azobis-2- (2-imidazolin-2-yl) propane hydrochloride, 2-carbamoyl azoisobutyronitrile and the like. A water-soluble azo-based initiator such as the azonitrile compound of the above; etc. can be used. These polymerization initiators include alkali metal sulfites such as sodium hydrogen sulfite, Fe (II) salts such as metadiosulfate, sodium hypophosphite, and molle salts, sodium hydroxymethanesulfinate dihydrate, and hydroxylamine hydrochloride. Accelerators such as salt, thiourea, L-ascorbic acid (salt), and elisorbic 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 solution polymerization is performed using a lower alcohol, aromatic hydrocarbon, aliphatic hydrocarbon, ester compound, or ketone compound as a solvent, or when bulk polymerization is performed, benzoylper oxide or lauroylper is used as a polymerization initiator. Peroxides such as oxides and sodium peroxides; hydroperoxides such as t-butylhydroperoxides and cumenehydroperoxides; azo compounds such as azobisisobutyronitrile; and the like can be used. When such a polymerization initiator is used, an accelerator such as an amine compound can also be used in combination. Further, when a water-lower alcohol mixed solvent is used, it can be appropriately selected and used from the above-mentioned various polymerization initiators or combinations of the polymerization initiator and the accelerator.

The reaction temperature at the time of polymerization of the monomer component is appropriately determined by the polymerization method, solvent, polymerization initiator, and chain transfer agent used. Such a reaction temperature is preferably 0 ° C. or higher, more preferably 30 ° C. or higher, further preferably 50 ° C. or higher, and preferably 150 ° C. or lower, more preferably 120 ° C. or lower. It is more preferably 100 ° C. or lower.

Any suitable method can be adopted as the method for charging the monomer component into the reaction vessel. Examples of such a charging method include 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 into the reaction vessel, and the rest is charged into the reaction vessel. Examples thereof include a method of dividing or continuously feeding. Specifically, a method in which the entire amount of the monomer (a) and the total amount of the monomer (b) are continuously charged into the reaction vessel, and a part of the monomer (a) is initially charged into the reaction vessel. A method in which the rest of the monomer (a) and the total amount of the monomer (b) are continuously charged into the reaction vessel, a part of the monomer (a) and a part of the monomer (b) are put into the reaction vessel. Examples thereof include a method in which the residue of the monomer (a) and the residue of the monomer (b) are alternately charged into the reaction vessel in several batches. Further, by continuously or stepwise changing the charging rate of each monomer into the reaction vessel during the reaction, the charging mass ratio of each monomer per unit time is continuously or stepwise changed. Two or more kinds of copolymers having different ratios of the structural unit (I) and the structural unit (II) may be synthesized at the same time during the polymerization reaction. The polymerization initiator may be charged into the reaction vessel from the beginning, may be added dropwise to the reaction vessel, or these may be combined depending on the intended purpose.

When polymerizing the monomer component, a chain transfer agent can be preferably used. When a chain transfer agent is used, it becomes easy to adjust the molecular weight of the obtained copolymer. Only one type of chain transfer agent may be used, or two or more types may be used.

As the chain transfer agent, any suitable chain transfer agent may be adopted. Examples of such a chain transfer agent include thiol-based chain transfer agents such as mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thioapple acid, and 2-mercaptoethanesulfonic acid; Secondary alcohols such as isopropanol; phosphite, hypophosphoric acid, and salts thereof (sodium bisulfite, potassium hypophosphate, etc.), sulfite, hydrogen sulfite, dithionic acid, metabisulfite, And lower oxides and salts thereof (sodium bisulfite, potassium sulfite, sodium hydrogen sulfite, potassium hydrogen sulfite, sodium bisulfite, potassium bisulfite, sodium metabisulfite, potassium metabisulfite, etc.), etc. Can be mentioned.

The produced polycarboxylic acid-based copolymer (A1) can be used as it is as a polycarboxylic acid-based copolymer (A1) that can be contained in the cement admixture of the present invention, but from the viewpoint of handleability, it can be used. It is preferable to adjust the pH of the reaction solution after the production of the polycarboxylic acid-based copolymer (A1) to 5 or more. However, in order to improve the polymerization rate, it is preferable to carry out 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 by using, for example, an inorganic salt such as a hydroxide or carbonate of a monovalent metal or a divalent metal; an alkaline substance such as ammonia; an organic amine;

The concentration of the produced polycarboxylic acid-based copolymer (A1) can be adjusted, if necessary, with respect to the solution obtained by the production.

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

<alkylene oxide adduct (A2) to active hydrogen bonded to the amino group of polyethyleneimine>
The alkylene oxide adduct (A2) to the active hydrogen bonded to the amino group of polyethyleneimine is an arbitrary appropriate average number of moles of alkylene oxide added to the active hydrogen bonded to the amino group of polyethyleneimine. Refers to the added adduct.

The alkylene oxide is preferably an alkylene oxide having 2 to 10 carbon atoms, more preferably an alkylene oxide having 2 to 8 carbon atoms, and more preferably 2 carbon atoms in that the effects of the present invention can be more exhibited. It is an alkylene oxide of ~ 6, particularly preferably an alkylene oxide having 2 to 4 carbon atoms, and most preferably an alkylene oxide having 2 to 3 carbon atoms (that is, ethylene oxide or propylene oxide). Further, the alkylene oxide may be one kind or two or more kinds.

The average number of moles of alkylene oxide added is preferably 1 mol to 1000 mol, more preferably 2 mol to 500 mol, still more preferably 3 mol to 300 mol, still more preferably 4 mol to 200 mol. It is more preferably 5 mol to 100 mol, further preferably 10 mol to 75 mol, particularly preferably 15 mol to 50 mol, and most preferably 20 mol to 40 mol. By adjusting the average number of moles of alkylene oxide added within the above range, the cement admixture of the present invention can improve the strength of the cured product of the cement composition more remarkably over a long period of time.

The mass average molecular weight (Mw) of the alkylene oxide adduct (A2) to the active hydrogen bonded to the amino group of polyethyleneimine is preferably 4000 to 10000000, more preferably 5000 to 5000000, and even more preferably. It is 1000 to 3000000, particularly preferably 2000 to 700,000, and most preferably 50,000 to 300,000. By adjusting the mass average molecular weight (Mw) of the alkylene oxide adduct (A2) to the active hydrogen bonded to the amino group of polyethyleneimine within the above range, the cement admixture of the present invention is a cement composition. The strength of the cured product can be improved more significantly over the long term.

≪Alkanolamine compound (B) ≫
As the alkanolamine compound (B), any suitable alkanolamine compound can be adopted as long as the effects of the present invention are not impaired. Examples of such an alkanolamine compound include a low molecular weight alkanolamine compound and a high molecular weight alkanolamine compound.

Examples of the low-molecular-weight alkanolamine compound include monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, methylethanolamine, methylisopropanolamine, methyldiethanolamine, and 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-hydroxypropyl) ethylenediamine, tris (2-hydroxybutyl) amine, And so on. Among these, preferred low-molecular-weight alkanolamine compounds include triisopropanolamine, N, N, N', N'-tetrakis (2-hydroxypropyl) ethylenediamine, and diisopropanolethanolamine. Other low-molecular-weight alkanolamine compounds include, for example, a monomer having a skeleton of triisopropanolamine.

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

≪Dispersant (C) ≫
The dispersant (C) is at least one selected from a polycarboxylic acid-based dispersant (C1), a sulfonic acid-based dispersant (C2), and a phosphoric acid-based dispersant (C3).

The dispersant (C) can contribute to improving the dispersibility of the cement composition in the cement admixture of the present invention.

The polycarboxylic acid-based dispersant (C1) may be one type or two or more types.

The sulfonic acid-based dispersant (C2) may be one type or two or more types.

The phosphoric acid-based dispersant (C3) may be one type or two or more types.

<Polycarboxylic acid dispersant (C1)>
The polycarboxylic acid-based dispersant (C1) is a structural unit (III) derived from an unsaturated polyalkylene glycol ether-based monomer (c) represented by ^{the general formula (3): YO (A 2} O) _n R ^0. It is a polycarboxylic acid-based copolymer having a structural unit (IV) derived from the unsaturated carboxylic acid-based monomer (d).

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 (C1) is preferably 37 mol% or more, preferably 40 mol% to 90. It is mol%, more preferably 40 mol% to 85 mol%, further preferably 45 mol% to 85 mol%, and particularly preferably 50 mol% to 80 mol%. When the content ratio of the structural unit having a carboxyl group or a salt thereof to all the structural units constituting the polycarboxylic acid-based dispersant (C1) is within the above range, the cement admixture of the present invention disperses the cement composition. The sex can be improved more significantly. The "carboxyl group or a salt thereof" here 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. ..

General formula (3): The structural unit (III) derived from the unsaturated polyalkylene glycol ether-based monomer (c) represented by ^{YO (A 2} O) _n R ^{0 is specifically a general formula (3).} 3) This is a structural unit in which the unsaturated double bond (C = C) of Y in the unsaturated polyalkylene glycol ether-based monomer (c) represented becomes −C—C− by the polymerization reaction.

In the general formula (3), Y represents an alkenyl group having 2 to 4 carbon atoms.

As Y, for example, a vinyl group (CH ₂ = CH- group), a 1-methyl-1-vinyl group (CH ₂ = C (CH ₃ ) -group), a 2-propenyl group (allyl group) (CH ₂ =). CHCH ₂ -group), 2-methyl-2-propenyl group (metallic group) (CH ₂ = C (CH ₃ ) -CH _2- group).

In the general formula (3), 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 (aliphatic alkyl group and alicyclic alkyl group), an alkenyl group having 1 to 30 carbon atoms, and a carbon atom number. Examples thereof include an alkynyl group of 1 to 30 and an aromatic group having 6 to 30 carbon atoms. A point capable of further exhibit the effect of the present invention, R ³ is preferably a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, more preferably, carbon hydrogen atom or 1 to 12 carbon atoms 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 (3), A ² O represents an oxyalkylene group having 2 to 18 carbon atoms. The oxyalkylene group preferably has 2 to 8 carbon atoms, more preferably 2 to 4 carbon atoms.

Examples of A ² 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 ² O structures exist, these different A ² 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 the oxyethylene group contains an oxyethylene group as an essential component. More specifically, with respect to 100 mol% of all oxyalkylene groups, 50 mol% or more is preferably an oxyethylene group, 80 mol% or more is more preferably an oxyethylene group, and 90 mol% or more is It is particularly preferably an oxyethylene group, and 100 mol% is particularly preferably an oxyethylene group.

In the general formula (3), n represents an average addition mole number of the oxyalkylene group represented by ^{A 2} 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 one mole of the compound.

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

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

In general formula (4) and structural unit (IV), R ^{7 to} R ⁹ represent the same or different hydrogen atom, methyl group, or − (CH ₂ ) _z COM group. The − (CH ₂ ) _z COM group may form an anhydride with _{the − (CH 2} ) _z COM group or other − (CH 2) z COM groups. z is an integer from 0 to 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-based monomer (d) represented by the general formula (4) include monocarboxylic acid-based monomers such as (meth) acrylic acid and crotonic acid, or salts thereof; maleic acid, Dicarboxylic acid-based monomers such as itaconic acid and fumaric acid or salts thereof; anhydrides of dicarboxylic acid-based monomers such as maleic acid, itaconic acid and fumaric acid or salts thereof; and the like. Examples of the salt referred to here 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 the alkaline earth metal salt include calcium salt and magnesium salt.

Examples of the organic ammonium salt include methylammonium salt, ethylammonium salt, dimethylammonium salt, diethylammonium salt, trimethylammonium salt, triethylammonium salt and the like.

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

The unsaturated carboxylic acid-based monomer (d) represented by the general formula (4) is preferably (meth) acrylic acid, maleic acid, or maleic anhydride in that the effects of the present invention can be further exhibited. It is more preferably acrylic acid or maleic acid.

The unsaturated carboxylic acid-based monomer (d) represented by the general formula (4) may be of only one type or of two or more types.

The total content ratio of the structural unit (III) and the structural unit (IV) in the polycarboxylic acid-based dispersant (C1) should be the main component in the structural units constituting the copolymer. Is preferable, 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 mass. %, Most preferably substantially 100% by mass. When the total content ratio of the structural unit (III) and the structural unit (IV) in the polycarboxylic acid-based dispersant (C1) is within the above range, the cement admixture of the present invention disperses the cement composition. It can contribute to the improvement of sex.

The polycarboxylic acid-based dispersant (C1) may contain a structural unit (V) derived from another monomer (e) in addition to the structural unit (III) and the structural unit (IV).

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

For the other monomer (e) and structural unit (V), the description in the section <Polycarboxylic acid-based copolymer (A1)> can be incorporated.

The content ratio of each structural unit in the polycarboxylic acid-based dispersant (C1) can be known by, for example, various structural analyzes (for example, NMR) of the polycarboxylic acid-based dispersant (C1). Further, the monomer calculated based on the amount of each monomer used in producing the polycarboxylic acid-based dispersant (C1) and the polymerization rate without performing various structural analyzes as described above. The content ratio of the derived structural unit may be used as the content ratio of each structural unit in the polycarboxylic acid-based dispersant (C1).

The content ratio of the structural unit (III) in the polycarboxylic acid-based dispersant (C1) is preferably 60% by mass to 99% by mass, more preferably 65% by mass to 97% by mass, and further preferably 70. It is from 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 (IV) in the polycarboxylic acid-based dispersant (C1) is preferably 1% by mass to 40% by mass, more preferably 3% by mass to 35% by mass, and further preferably 5. It is by mass% to 30% by mass, and particularly preferably 10% by mass to 25% by mass.

When determining the content ratio of structural units in the polycarboxylic acid-based dispersant (C1), if the structural unit has a carboxyl group, the calculation is performed assuming that it is completely neutralized (sodium salt). ..

The mass average molecular weight (Mw) of the polycarboxylic acid-based dispersant (C1) is preferably 1000 or more, more preferably 3000 to 500000, still more preferably 5000 to 300000, still more preferably 1000 to 250,000. It is more preferably 20000 to 20000, particularly preferably 30,000 to 150,000, and most preferably 40,000 to 100,000. When the mass average molecular weight (Mw) of the polycarboxylic acid-based dispersant (C1) is within the above range, the cement admixture of the present invention can contribute to the improvement of the dispersibility of the cement composition.

The polycarboxylic acid-based dispersant (C1) can be produced by any suitable method as long as the effects of the present invention are not impaired. Preferably, as the method for producing the polycarboxylic acid-based dispersant (C1), the above-mentioned method for producing the polycarboxylic acid-based copolymer (A1) can be incorporated.

<Sulfonic acid-based dispersant (C2)>
The sulfonic acid-based dispersant (C2) is a dispersant that develops dispersibility with respect to cement mainly by electrostatic repulsion caused by a sulfonic acid group, and any suitable sulfonic acid-based dispersant can be used. , It is preferable that the compound has an aromatic group in the molecule. Specifically, polyalkylaryl sulfonate-based sulfonic acid-based dispersants such as naphthalene sulfonic acid formaldehyde condensate, methyl naphthalene sulfonic acid formaldehyde condensate, anthracene sulfonic acid formaldehyde condensate, etc .; , Melamine formalin resin sulfonate sulfonic acid dispersant; aromatic amino sulfonate sulfonic acid dispersant such as aminoaryl sulfonic acid-phenol-formaldehyde condensate; lignin sulfonate, modified lignin sulfonate Lignin sulfonate-based sulfonic acid-based dispersant; polystyrene sulfonate-based sulfonic acid-based dispersant; and the like. In the case of concrete having a high water / cement ratio, a lignin sulfonate-based dispersant is preferably used, while in the case of concrete having a medium water / cement ratio, which requires higher water reduction performance, a lignin sulfonate-based dispersant is preferably used. , Polyalkylaryl sulfonate-based, melamine formalin resin sulfonate-based, aromatic amino sulfonate-based, polystyrene sulfonate-based dispersants and the like are preferably used.

<Phosphoric acid-based dispersant (C3)>
As the phosphoric acid-based dispersant (C3), any suitable phosphoric acid-based dispersant having a phosphoric acid group in the molecule can be used, and for example, the phosphoric acid-based dispersion described in JP-A-2006-52381. Agents, phosphoric acid-based dispersants described in JP-A-2008-517080, and the like can be mentioned.

≪≪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.

As the aggregate, any suitable aggregate such as fine aggregate (sand or the like) or coarse aggregate (crushed stone or the like) can be adopted. Examples of such aggregates include gravel, crushed stone, granulated slag, and recycled aggregate. Further, examples of such an aggregate include refractory aggregates such as silica stone, clay, zircon, high alumina, silicon carbide, graphite, chromium, chromog and magnesia.

The cement composition of the present invention may contain any suitable cement additive (material) as long as the effects of the present invention are not impaired. Examples of such a cement additive (material) include cement additives (materials) as exemplified in the following (1) to (13). As the blending amount of the cement additive (material), any appropriate blending amount can be adopted according to the type and purpose of the cement additive (material) to be used.

(1) Water-soluble polymer substances: nonionic cellulose ethers such as methyl cellulose, ethyl cellulose and carboxymethyl cellulose; polysaccharides produced by microbial fermentation such as yeast glucan, xanthan gum and β-1.3 glucan; polyacrylamide and the like. ..

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

(3) Curing retardant: oxycarboxylic acid such as gluconic acid, glucoheptonic acid, arabonic acid, malic acid, citric acid or a salt thereof; sugar and sugar alcohol; polyhydric alcohol such as glycerin; aminotri (methylenephosphonic acid) and the like Phosphonic acid and its derivatives, etc.

The ratio of the curing retarder to the compound (A) is preferably 1% by mass to 1000% by mass, more preferably 2% by mass to 700% by mass, and further preferably 5% by mass to 500% by mass. It is particularly preferably 10% by mass to 300% by mass, and most preferably 20% by mass to 200% by mass.

(4) Fast-strengthening agent / accelerator: soluble calcium salts such as calcium chloride, calcium nitrite, calcium nitrate, calcium bromide, 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-based defoaming agent: 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 salts; polyoxyalkylene alkyl phosphate esters; polyoxypropylene polyoxyethylene laurylamine (propylene oxide average 1 to 20 mol adduct, ethylene oxide average 1 to 20 mol adduct, etc.), alkylene oxide Polyoxyalkylene alkylamines such as amines derived from fatty acids obtained from the added hardened beef fat (propylene oxide average 1 to 20 mol additions, ethylene oxide average 1 to 20 mol additions, etc.); polyoxyalkylene amides and the like.

(6) Defoamers other than oxyalkylene-based: Mineral oil-based, oil-based, fatty acid-based, fatty acid ester-based, alcohol-based, amide-based, phosphoric acid ester-based, metal soap-based, silicone-based defoaming agents.

(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 salt thereof, polyoxyethylene alkyl (phenyl) ether phosphate ester or salt thereof, protein material, alkenyl sulfosuccinic acid, α-olefin sulfonate, etc.

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

(9) Waterproofing agent: fatty acid (salt), fatty acid ester, fat, silicone, paraffin, asphalt, wax, etc.

(10) Rust inhibitor: nitrite, phosphate, zinc oxide, etc.

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

(12) Expansion material; ettringite-based, coal-based, etc.

(13) A polycarboxylic acid-based copolymer having a polyoxyalkylene group and a carboxyl group other than the polycarboxylic acid-based copolymer (A1) and the polycarboxylic acid-based dispersant (C1); for example, the general formula (3). ): An unsaturated polyalkylene glycol ether-based monomer (c) represented by YO (A ² O) _n R ⁰ (in the general formula (3), Y represents an alkenyl group having 5 to 8 carbon atoms. , R ⁰ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, A ² O represents an oxyalkylene group having 2 to 18 carbon atoms, and n represents an oxy represented by ^{A 2 O.} Represents the average number of moles of alkylene group added, n is 2 to 300) Polycarboxylic acid having a structural unit (III) derived from it and an unsaturated carboxylic acid monomer (d) derived from it (IV). Acid-based copolymers, etc.

Other known cement additives (materials) include cement wetting agents, thickeners, separation reducing agents, coagulants, drying shrinkage reducing agents, strength enhancing agents, self-leveling agents, coloring agents, fungicides and the like. be able to. Only one kind of these known cement additives (materials) may be used, or two or more kinds thereof may be used.

As the cement contained in the cement composition of the present invention, any suitable cement can be adopted. Examples of such cement include Portoland cement (ordinary, early-strength, ultra-fast-strength, moderate heat, sulfate-resistant and each low-alkali form), various mixed cements (blast furnace cement, silica cement, fly ash cement), and the like. White Portoland cement, alumina cement, ultra-fast-hardening cement (1 clinker fast-hardening cement, 2 clinker fast-hardening cement, magnesium phosphate cement), grout cement, oil well cement, low heat-generating cement (low-heat-generating blast furnace cement, fly ash mixed low) Heat-generating blast furnace cement, belite-rich cement), ultra-high-strength cement, cement-based solidifying material, eco-cement (cement manufactured from one or more of municipal waste incineration ash and sewage sludge incineration ash). Further, fine powder such as blast furnace slag, fly ash, cinder ash, clinker ash, husk ash, silica powder, limestone powder and gypsum 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 kind or two or more kinds.

In the cement composition of the present invention, any appropriate value can be set as the unit water amount per ^{1 m 3 of the cement composition, 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 to rich concrete, and can be used for both high-strength concrete having a large unit cement amount ^{and poor concrete with a unit cement amount of 300 kg / m 3} or less. It is valid.

The cement composition of the present invention may be effective for ready-mixed concrete, concrete for secondary concrete products, concrete for centrifugal molding, concrete for vibration compaction, steam curing concrete, sprayed concrete 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, and 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, a method of kneading the constituents in a mixer can be mentioned.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. Unless otherwise specified, the term "parts" means parts by mass, and the term "%" means% by mass.

<Mass average molecular weight analysis conditions>
-Columns used: TSKguardcolumnα + TSKgelα-5000 + TSKgelα-4000 + TSKgelα-3000 manufactured by Tosoh Corporation were connected and used one by one.
-Eluent: Sodium dihydrogen phosphate, 2H ₂ O: 62.4 g, disodium hydrogen phosphate, 12H ₂ O: 143.3 g in a solution dissolved in ion-exchanged water: 7794.3 g, acetonitrile: 2000 g Was used as a mixed solution.
-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 cell capacity, 670 nm wavelength.
-Standard sample: Polyethylene glycol SE-8 (Mw = l07000) manufactured by Tosoh Corporation was used, the dn / dC was 0.135 ml / g, and the refractive index of the eluent was 1.333, and the device constant was determined.
-Driving amount Standard sample: 100 μL of the solution dissolved in the above eluent was injected so that the polymer concentration was 0.2 vol%.
Sample: 100 μL of the solution dissolved in the above eluent was injected so that the polymer concentration became 1.0 vol%.
-Flow velocity: 0.8 ml / min
-Column temperature: 40 ° C

<Concrete test>
Ordinary Portoland cement (manufactured by Pacific Cement Co., Ltd.) as cement, land sand from Oigawa water system as fine aggregate, crushed stone from Qinghai as coarse aggregate, tap water as kneading water, cement: 301 ^{kg / m 3} , water: 160 kg / m ³ , fine aggregate: 821 kg / m ³ , coarse aggregate: 1002 kg / m ³ , fine aggregate ratio (fine aggregate / fine coarse aggregate + coarse aggregate) (volume ratio): 47%, water / cement ratio A concrete composition was prepared with a composition of (mass ratio) = 0.53. The materials used for the test, the forced kneading mixer, and the measuring instruments were adjusted in the above test temperature atmosphere so that the temperature of the concrete composition became the test temperature of 20 ° C., and the kneading and each measurement were performed as described above. The test was performed in a temperature atmosphere. Further, 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 4.0 ± 0.5%. did.
Under the above conditions, concrete was produced using a forced kneading mixer with a kneading time of 90 seconds, and the slump value and the amount of air were measured. The slump value and the amount of air were measured in accordance with the 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 a compressive strength test, and the compressive strength after 28 days was measured under the following conditions.
Specimen preparation: 100 mm x 200 mm
Specimen curing (28 days): Temperature approx. 20 ° C, humidity 60%, constant temperature and humidity constant air curing for 24 hours, then curing in water for 27 days Specimen polishing: Specimen surface polishing (using specimen polishing finishing machine)
Compressive strength measurement: Automatic compressive strength measuring device (Maekawa Mfg. Co., Ltd.)

[Manufacturing Example A-1]
120.5 g of ion-exchanged water was placed in a glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen introduction tube and a reflux condenser, and the reactor was replaced with nitrogen under stirring to raise the temperature to 80 ° C. .. Next, an aqueous solution prepared by dissolving 129.6 g of methoxypolyethylene glycol methacrylate (average number of moles of ethylene oxide added: 20 mol), 5.43 g of methacrylic acid, and 0.41 g of 3-mercaptopropionic acid in 33.75 g of ion-exchanged water was added. Dropped over time. At the same time, an aqueous solution prepared by dissolving 1.35 g of ammonium persulfate in 8.6 g of ion-exchanged water was added dropwise over 5 hours. After completion of the dropping, stirring was continued at 80 ° C. for 1 hour to complete the polymerization reaction, and an aqueous solution of a polycarboxylic acid-based copolymer having a mass average molecular weight (Mw) of 50,000 was obtained. A sodium hydroxide aqueous solution was added to the obtained polycarboxylic acid-based copolymer aqueous solution, and the mixture was neutralized to pH 7. In this way, a polycarboxylic acid-based copolymer (A-1) was obtained. The polymerization rate of methoxypolyethylene glycol methacrylate of the obtained copolymer was 94%, and the polymerization rate of methacrylic acid was 98%. The copolymer composition ratio of the polymer (A-1) was calculated from the polymerization rate of each raw material. Specifically, the polymerization rate of 94% with respect to the amount of 129.6 g of methoxypolyethylene glycol methacrylate used and the polymerization rate of 98% with respect to 5.43 g of methacrylic acid are such that the content ratio of methoxypolyethylene glycol methacrylate of the polymer is 129.6 × 0.94. / (129.6 × 0.94 + 5.43 × 0.98 × 108/86) = 95% (methacrylic acid is converted to sodium salt). Table 1 shows the copolymer composition ratio (mass%), copolymer composition ratio (mol%), and mass average molecular weight of the obtained polymer (A-1).

[Manufacturing Examples A-2, A-3, A-7, C-1 to C-4, C-7 to C-9]
The copolymerization reaction was carried out according to the method described in JP-A-2004-519406, and the copolymers A-2, A-3, and the copolymers A-2, A-3, having the copolymerization composition ratio and mass average molecular weight as shown in Tables 1 and 3 were carried out. Aqueous solutions of A-7, C-1 to C-4, and C-7 to C-9 were obtained.

[Manufacturing Example A-4]
An average of 50 mol of ethylene oxide was added to active hydrogen bonded to the amino group of polyethyleneimine having a molecular weight of 1800 to obtain an adduct (A-4) (mass average molecular weight of 96000). The results are shown in Table 2.

[Manufacturing Example A-5]
The same procedure as in Production Example A-4 was carried out except for the changes as shown in Table 2, to obtain an adduct (A-5) (mass average molecular weight of 3500). The results are shown in Table 2.

[Manufacturing Example A-6]
The same procedure as in Production Example A-4 was carried out except for the changes as shown in Table 2, to obtain an adduct (A-6) (mass average molecular weight of 13000). The results are shown in Table 2.

[Manufacturing Example C-5]
The copolymerization reaction was carried out according to the method described in JP-A-2006-52381, and methoxypolyethylene glycol methacrylate (average number of molar additions of ethylene oxide: 23 mol), monophosphate (2-hydroxyethyl) methacrylic acid ester, and phosphoric acid. A phosphoric acid-based dispersant (C) containing a copolymer having a copolymer composition ratio of di- [2- (hydroxyethyl) methacrylic acid] of 30/47/23 (mol%) and a mass average molecular weight (Mw) of 20000. An aqueous solution of -5) was obtained.

[Manufacturing Example C-6]
The condensation reaction was carried out according to the method described in JP-A-2008-517080, and polyethylene glycol (average addition of ethylene oxide: 20 mol) by condensation of monophenyl ether and phenoxyethanol phosphate with formaldehyde. Number of moles: 20 mol) An aqueous solution of a phosphoric acid-based dispersant (C-6) containing a condensate having a monophenyl ether to phenoxyethanol phosphate ratio of 30/70 (mol%) and a mass average molecular weight (Mw) of 25,000. Obtained.

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

[Example 2]
The polyoxyalkylene compound (A) is a polycarboxylic acid-based copolymer (A-2), the alkanolamine compound (B) is EDIPA (hydroxyethyldiisopropanolamine, manufactured by Aldrich), and the dispersant (C) is a polycarboxylic acid. A cement admixture (2) was prepared by blending as shown in Table 4 using the system dispersant (C-2). The results are shown in Table 4.

[Example 3]
Polycarboxylic acid copolymer (A-3) as polyoxyalkylene compound (A), THEDA (N, N, N', N'-tetrakis (2-hydroxypropyl) ethylenediamine as alkanolamine compound (B), Tokyo A cement admixture (3) was prepared by using Mighty 150 (manufactured by Kao) as a dispersant (C) (manufactured by Kasei Co., Ltd.) and blending as shown in Table 4. The results are shown in Table 4.

[Example 4]
Ethylene oxide adduct (A-4) to active hydrogen bonded to the amino group of polyethyleneimine as polyoxyalkylene compound (A), EDIPA (hydroxyethyldiisopropanolamine, manufactured by Aldrich) as alkanolamine compound (B) As a dispersant (C), Master Posolis No. 8 (manufactured by BASF Japan Ltd.) was used and blended as shown in Table 4 to prepare a cement admixture (4). The results are shown in Table 4.

[Example 5]
As a polyoxyalkylene compound (A), an ethylene oxide adduct (A-5) to active hydrogen bonded to the amino group of polyethyleneimine, and as an alkanolamine compound (B), THEDA (N, N, N', N'- Tetrax (2-hydroxypropyl) ethylenediamine (manufactured by Tokyo Kasei Co., Ltd.), a polycarboxylic acid-based dispersant (C-3) as a dispersant (C), and a mixture as shown in Table 4 to prepare a cement admixture (5) Was prepared. The results are shown in Table 4.

[Example 6]
As a polyoxyalkylene compound (A), an ethylene oxide adduct (A-6) to active hydrogen bonded to the amino group of polyethyleneimine, and as an alkanolamine compound (B), TIPA (triisopropanolamine, manufactured by Wako Pure Chemical Industries, Ltd.) ), A polycarboxylic acid-based dispersant (C-4) was used as the dispersant (C), and the mixture was blended as shown in Table 4 to prepare a cement admixture (6). The results are shown in Table 4.

[Example 7]
The polyoxyalkylene compound (A) is a polycarboxylic acid-based copolymer (A-2), the alkanolamine compound (B) is TIPA (triisopropanolamine, manufactured by Wako Pure Chemical Industries, Ltd.), and the dispersant (C) is phosphoric acid. A cement admixture (7) was prepared by blending as shown in Table 4 using the system dispersant (C-5). The results are shown in Table 4.

[Example 8]
As a polyoxyalkylene compound (A), an alkylene oxide adduct (A-6) to active hydrogen bonded to the amino group of polyethyleneimine, and as an alkanolamine compound (B), EDIPA (hydroxyethyldiisopropanolamine, manufactured by Aldrich) ), A phosphoric acid-based dispersant (C-6) was used as the dispersant (C), and the mixture was blended as shown in Table 4 to prepare a cement admixture (8). The results are shown in Table 4.

[Example 9]
The polyoxyalkylene compound (A) is an alkylene oxide adduct (A-4) to active hydrogen bonded to the amino group of polyethyleneimine, and the alkanolamine compound (B) is THEDA (N, N, N', N'. -Tetrax (2-hydroxypropyl) ethylenediamine (manufactured by Tokyo Kasei Co., Ltd.) and Mighty 150 (manufactured by Kao Co., Ltd.) as the dispersant (C) were used and blended as shown in Table 4 to prepare a cement admixture (9). .. The results are shown in Table 4.

[Example 10]
Polycarboxylic acid copolymer (A-2) as polyoxyalkylene compound (A), THEDA (N, N, N', N'-tetrakis (2-hydroxypropyl) ethylenediamine as alkanolamine compound (B), Tokyo As a dispersant (C), Master Posolis No. 8 (manufactured by BASF Japan Ltd.) was used and blended as shown in Table 4 to prepare a cement admixture (10). The results are shown in Table 4.

[Example 11]
The polyoxyalkylene compound (A) is a polycarboxylic acid-based copolymer (A-3), the alkanolamine compound (B) is EDIPA (hydroxyethyldiisopropanolamine, manufactured by Aldrich), and the dispersant (C) is a phosphoric acid-based compound. A cement admixture (11) was prepared by blending as shown in Table 4 using a dispersant (C-5). The results are shown in Table 4.

[Example 12]
The polyoxyalkylene compound (A) is a polycarboxylic acid-based copolymer (A-7), the alkanolamine compound (B) is TIPA (triisopropanolamine, manufactured by Wako Pure Chemical Industries, Ltd.), and the dispersant (C) is phosphoric acid. A cement admixture (12) was prepared by blending as shown in Table 4 using the system dispersant (C-6). The results are shown in Table 4.

[Example 13]
The polyoxyalkylene compound (A) is a polycarboxylic acid-based copolymer (A-1), the alkanolamine compound (B) is TIPA (triisopropanolamine, manufactured by Wako Pure Chemical Industries, Ltd.), and the dispersant (C) is polycarboxylic acid. An acid-based dispersant (C-7) was used and blended as shown in Table 4 to prepare a cement admixture (13). The results are shown in Table 4.

[Example 14]
As a polyoxyalkylene compound (A), an alkylene oxide adduct (A-4) to active hydrogen bonded to the amino group of polyethyleneimine, and as an alkanolamine compound (B), EDIPA (hydroxyethyldiisopropanolamine, manufactured by Aldrich) ), A polycarboxylic acid-based dispersant (C-8) was used as the dispersant (C), and the mixture was blended as shown in Table 4 to prepare a cement admixture (14). The results are shown in Table 4.

[Example 15]
Polycarboxylic acid copolymer (A-3) as polyoxyalkylene compound (A), THEDA (N, N, N', N'-tetrakis (2-hydroxypropyl) ethylenediamine as alkanolamine compound (B), Tokyo A cement admixture (15) was prepared by using a polycarboxylic acid-based dispersant (C-9) as the dispersant (C) (manufactured by Kasei Co., Ltd.) and blending as shown in Table 4. The results are shown in Table 4.

[Comparative Example 1]
As shown in Table 4, the polycarboxylic acid-based dispersant (C-2) was used as the cement admixture (C1). The results are shown in Table 4.

[Comparative Example 2]
As shown in Table 4, Mighty 150 (manufactured by Kao Corporation) was used as a cement admixture (C2). The results are shown in Table 4.

[Comparative Example 3]
As shown in Table 4, Master Pozoris No. 8 (manufactured by BASF Japan Ltd.) was used as a cement admixture (C3). The results are shown in Table 4.

[Comparative Example 4]
As shown in Table 4, the polycarboxylic acid-based dispersant (C-4) was used as the cement admixture (C4). The results are shown in Table 4.

[Comparative Example 5]
As shown in Table 4, the phosphoric acid-based dispersant (C-6) was used as the cement admixture (C5). The results are shown in Table 4.

As shown in Table 4, the 28-day compressive strengths of Examples 1 to 15 showed a remarkably excellent effect.

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

Claims (2)

A cement admixture containing a polyoxyalkylene compound (A), an alkanolamine compound (B), and a dispersant (C).
The polyoxyalkylene compound (A), an alkylene oxide adduct to the active hydrogen bonded to the amino group of ports Li ethyleneimine (A2),
The dispersant (C)
(Iii) General formula (3): YO (A ² O) _n R ⁰ is represented by an unsaturated polyalkylene glycol ether-based monomer (c) (in the general formula (3), Y has 2 carbon atoms. Represents an alkenyl group of ~ 4, R ⁰ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, A ² O represents an oxyalkylene group having 2 to 18 carbon atoms, and n is A. represents the average number of moles of the oxyalkylene group represented by ^{2 O,} n is 2 to 300.) structural units (III) with an unsaturated carboxylic acid monomer derived (d) structural units derived from ( Polycarboxylic acid-based dispersant (C1), which is a polycarboxylic acid-based copolymer having IV),
(Iv) Sulfonic acid-based dispersant (C2),
(V) Phosphoric acid-based dispersant (C3),
At least one selected from
Cement admixture . A cement composition containing a polyoxyalkylene compound (A), an alkanolamine compound (B), a dispersant (C), and cement.
The polyoxyalkylene compound (A), an alkylene oxide adduct to the active hydrogen bonded to the amino group of ports Li ethyleneimine (A2),
The dispersant (C)
(Iii) General formula (3): YO (A ² O) _n R ⁰ is represented by an unsaturated polyalkylene glycol ether-based monomer (c) (in the general formula (3), Y has 2 carbon atoms. Represents an alkenyl group of ~ 4, R ⁰ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, A ² O represents an oxyalkylene group having 2 to 18 carbon atoms, and n is A. represents the average number of moles of the oxyalkylene group represented by ^{2 O,} n is 2 to 300.) structural units (III) with an unsaturated carboxylic acid monomer derived (d) structural units derived from ( Polycarboxylic acid-based dispersant (C1), which is a polycarboxylic acid-based copolymer having IV),
(Iv) Sulfonic acid-based dispersant (C2),
(V) Phosphoric acid-based dispersant (C3),
At least one selected from
Cement composition .