JP6243655B2 - Cement admixture and cement composition using the same - Google Patents

Description

  The present invention relates to a cement admixture and a cement composition using the same. More specifically, when mixed with a so-called cement composition (cement composition) such as cement paste, mortar, concrete, etc., it is excellent in water reduction and slump loss prevention performance, and can reduce the viscosity of the produced cement composition. The present invention relates to a cement admixture and a cement composition containing the cement admixture.

  In order to improve the workability and durability of concrete, it is effective to reduce the amount of unit water in the concrete. However, it is known that when the unit water amount is reduced, the fluidity of concrete is lowered and the workability is impaired. Therefore, in order to ensure efficient workability of the concrete even when the unit water amount is reduced, various dispersants having a function of dispersing cement particles are used.

  Examples of such dispersants include AE water reducing agents such as lignin sulfonic acid dispersants and oxycarboxylic acids; high performance AE water reducing agents such as naphthalene sulfonic acid dispersants, amino sulfonic acid dispersants and polycarboxylic acid dispersants. Agents (Patent Documents 1 to 4) are known.

  These dispersants are required to have initial water-reducing properties and slump retention properties, and in recent years, there has been an increasing demand for slump retention properties. In concrete construction, after being manufactured at a production plant, it is transported to a construction site by a truck agitator car, unloaded from a pump car, and pumped to a placement site for construction. Therefore, it takes a long time from being manufactured to being placed on site. For this reason, unless the slump retainability is imparted to the concrete, the workability is significantly deteriorated.

  For this reason, cement admixtures for improving the slump retention of cement compositions (cement paste, concrete, mortar, etc.) have been proposed. For example, a copolymer of a polyethylene glycol monoallyl ether monomer and a (meth) acrylic acid monomer (Patent Document 5), a polyalkylene glycol mono (meth) acrylic acid ester monomer and (meth) A copolymer of an acrylic acid monomer (Patent Document 6) and a copolymer of a specific unsaturated polyalkylene glycol ether monomer and an unsaturated dicarboxylic acid monomer (Patent Document 7) have been proposed. ing.

JP-A-9-86990 JP 2005-281022 A JP-A-11-157898 JP 2003-146717 A Japanese Examined Patent Publication No. Sho 62-025164 JP 58-075452 Japanese Patent No. 3374369

  However, with the cement admixture described in Patent Documents 5 to 7, it is still difficult to satisfactorily solve the slump retention property and the concrete viscosity.

  There was also a problem that the viscosity of the cement composition increased. The increase in the viscosity of the cement composition significantly deteriorates the workability of the cement composition, increases the energy loss from concrete production to placement, and increases the environmental load. Moreover, the increase in the viscosity of the cement composition is not enough to fill the concrete at the time of placing, and causes the strength of the hardened concrete to be reduced.

  Therefore, in the present invention, in order to solve the above-mentioned problems, it has excellent cement dispersibility and slump retainability, can reduce the viscosity of the cement composition and improve workability (workability), and environment. An object of the present invention is to provide a cement admixture capable of reducing the load and a cement composition using the same.

  As a result of intensive studies to achieve the above object, the present inventors have found that a structural unit having an alkenyl group having a specific number of carbon atoms and a structural unit of an unsaturated monocarboxylic acid ester having a specific number of carbon atoms. The present inventors have found that the above problems can be solved by using a cement admixture containing a polycarboxylic acid-based copolymer containing or a salt (A) thereof, and have reached the present invention.

（式中、Ｒ¹は、炭素原子数２〜５のアルケニル基を表す。Ａ¹Ｏは、同一若しくは異なって、炭素原子数２〜１８のオキシアルキレン基を表す。ｎ１は、オキシアルキレン基の平均付加モル数であり、１〜１００の数を表す。Ｒ²は、水素原子または炭素原子数１〜３０の炭化水素基を表す。）

（式中、Ｒ³、Ｒ⁴およびＲ⁵は、それぞれ独立に、水素原子または炭素原子数１〜３のアルキル基を表す。ｍは、０〜２の数を表す。Ａ²Ｏは、同一若しくは異なって、炭素原子数２〜１８のオキシアルキレン基を表す。ｎ２は、オキシアルキレン基の平均付加モル数であり、１〜１００の数を表す。Ｘは、水素原子または炭素原子数１〜３０の炭化水素基を表す。）
〔２〕前記単量体（ＩＩ）が、一般式（２）中のｎ２が１〜５である単量体（ＩＩａ）及び一般式（２）中のｎ２が６〜１００である単量体（ＩＩｂ）を含む上記〔１〕に記載のセメント混和剤。
〔３〕前記単量体（ＩＩ）中の前記単量体（ＩＩａ）及び前記単量体（ＩＩｂ）の重量比率（ＩＩａ）／（ＩＩｂ）が１／９９〜９９／１である上記〔２〕に記載のセメント混和剤。
〔４〕前記ポリカルボン酸系共重合体またはその塩（Ａ）の重量平均分子量が、ポリエチレングリコール換算で５，０００〜６０，０００である〔１〕〜〔３〕のいずれか一項に記載のセメント混和剤。
〔５〕前記ポリカルボン酸系共重合体またはその塩（Ａ）が、前記共重合体をアルカリ性物質で中和して得られる塩である〔１〕〜〔４〕のいずれか一項に記載のセメント混和剤。
〔６〕（ポリ）アルキレングリコールアルケニルエーテル系単量体（Ｂ）をさらに含有する〔１〕〜〔５〕のいずれか一項に記載のセメント混和剤。
〔７〕前記（ポリ）アルキレングリコールアルケニルエーテル系単量体（Ｂ）の含有割合が、ポリカルボン酸系共重合体またはその塩（Ａ）に対して１〜９０重量％である〔１〕〜〔６〕のいずれか一項に記載のセメント混和剤。
〔８〕両末端基が水素原子である水溶性ポリアルキレングリコール（Ｃ）をさらに含有する〔１〕〜〔７〕のいずれか一項に記載のセメント混和剤。
〔９〕前記両末端基が水素原子である水溶性ポリアルキレングリコール（Ｃ）の含有割合が、ポリカルボン酸系共重合体またはその塩（Ａ）に対して０．０１〜５重量％である、〔１〕〜〔８〕のいずれか一項に記載のセメント混和剤。
〔１０〕前記単量体（Ｉ）、前記単量体（ＩＩＩ）、および単量体（Ｉ）および（ＩＩＩ）と共重合可能なその他の単量体（ＶＩ）を、共重合させることにより得られるポリカルボン酸系共重合体またはその塩（Ｄ）および／または前記単量体（ＩＩ）、前記単量体（ＩＩＩ）、および単量体（ＩＩ）および（ＩＩＩ）と共重合可能なその他の単量体（ＶＩＩ）を、共重合させることにより得られるポリカルボン酸系共重合体またはその塩（Ｅ）をさらに含有する〔１〕〜〔９〕のいずれか一項に記載のセメント混和剤。
〔１１〕〔１〕〜〔１０〕のいずれか一項に記載のセメント混和剤を含有するセメント組成物。 That is, the present invention includes the following [1] to [11].
[1] Monomer (I) represented by the following general formula (1) 5 to 97% by weight, monomer (II) represented by the following general formula (2) 5 to 97% by weight, unsaturated mono Obtained by copolymerizing 1 to 50% by weight of carboxylic acid monomer (III) and 0 to 50% by weight of other monomer (IV) copolymerizable with monomers (I) to (III). A cement admixture having a polycarboxylic acid copolymer or a salt thereof (A).

(In the formula, R ¹ represents an alkenyl group having 2 to 5 carbon atoms. A ¹ O is the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. N1 represents an oxyalkylene group. (The average number of moles added represents a number of 1 to 100. R ² represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.)

(In the formula, R ³ , R ⁴ and R ⁵ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. M represents a number of 0 to ^2. A ² O is the same. Or, differently, it represents an oxyalkylene group having 2 to 18 carbon atoms, n2 is the average number of added moles of the oxyalkylene group, and represents a number of 1 to 100. X is a hydrogen atom or 1 to 1 carbon atoms. Represents 30 hydrocarbon groups.)
[2] The monomer (II) is a monomer (IIa) in which n2 in the general formula (2) is 1 to 5 and a monomer in which n2 in the general formula (2) is 6 to 100 The cement admixture according to the above [1], comprising (IIb).
[3] The above-mentioned [2], wherein the weight ratio (IIa) / (IIb) of the monomer (IIa) and the monomer (IIb) in the monomer (II) is 1/99 to 99/1 ] Cement admixture as described in.
[4] The weight average molecular weight of the polycarboxylic acid copolymer or salt (A) thereof is 5,000 to 60,000 in terms of polyethylene glycol, [1] to [3] Cement admixture.
[5] The polycarboxylic acid copolymer or the salt (A) thereof is a salt obtained by neutralizing the copolymer with an alkaline substance, according to any one of [1] to [4]. Cement admixture.
[6] The cement admixture according to any one of [1] to [5], further containing a (poly) alkylene glycol alkenyl ether monomer (B).
[7] The content ratio of the (poly) alkylene glycol alkenyl ether monomer (B) is 1 to 90% by weight based on the polycarboxylic acid copolymer or a salt thereof (A). [6] The cement admixture according to any one of [6].
[8] The cement admixture according to any one of [1] to [7], further containing a water-soluble polyalkylene glycol (C) in which both terminal groups are hydrogen atoms.
[9] The content ratio of the water-soluble polyalkylene glycol (C) in which both terminal groups are hydrogen atoms is 0.01 to 5% by weight with respect to the polycarboxylic acid copolymer or salt (A) thereof. The cement admixture according to any one of [1] to [8].
[10] By copolymerizing the monomer (I), the monomer (III), and another monomer (VI) copolymerizable with the monomers (I) and (III) Copolymerizable with the resulting polycarboxylic acid copolymer or salt (D) and / or monomer (II), monomer (III), and monomers (II) and (III) The cement according to any one of [1] to [9], further comprising a polycarboxylic acid copolymer obtained by copolymerizing another monomer (VII) or a salt (E) thereof. Admixture.
[11] A cement composition containing the cement admixture according to any one of [1] to [10].

  According to the present invention, when a cement composition is used, it has excellent cement dispersibility and slump retention, can suppress the viscosity of the cement composition, improve workability, and reduce environmental load. A cement admixture and a cement composition using the same are provided.

  The cement admixture of the present invention comprises a monomer (I) represented by the general formula (1), a monomer (II) represented by the general formula (2), an unsaturated monocarboxylic acid-based monomer It is a cement admixture having a copolymer of the body (III) and other monomers (IV) copolymerizable with the monomers (I) to (III).

  The polycarboxylic acid copolymer or its salt (A) is composed of 5 to 97% by weight of monomer (I) represented by general formula (1) and monomer (II) represented by general formula (2). ) 5 to 97% by weight, unsaturated monocarboxylic acid monomer (III) 1 to 50% by weight, other monomer (IV) copolymerizable with (I) to (III) 0 to 50% by weight Can be obtained by copolymerization. The copolymer comprises a structural unit derived from monomer (I), a structural unit derived from monomer (II), a monomer (III), and a structural unit derived from monomer (IV). It is a copolymer having as an essential structural unit.

  The blending ratio of each monomer in obtaining the polycarboxylic acid copolymer or salt (A) is as follows. The blending ratio of the monomer (I) is 5% to 97% by weight, preferably 20% to 97% by weight, more preferably 30% to 97% by weight, and still more preferably 40% to 97%. % By weight, still more preferably 50% by weight to 97% by weight, particularly preferably 60% by weight to 97% by weight. The blending ratio of the monomer (II) is 5% to 97% by weight, preferably 20% to 97% by weight, more preferably 30% to 97% by weight, still more preferably 40% to 97%. % By weight, still more preferably 50% by weight to 97% by weight, particularly preferably 60% by weight to 97% by weight. The blending ratio of the monomer (III) is 1% by weight to 50% by weight, preferably 2% by weight to 40% by weight, more preferably 2% by weight to 30% by weight, and still more preferably 2%. % By weight to 25% by weight. The compounding ratio of the monomer (IV) is 0 to 50% by weight, preferably 0 to 40% by weight. In addition, when the blending ratio is set to the blending ratio of the monomer (I) + the blending ratio of the monomer (II) + the blending ratio of the monomer (III) + the monomer (IV) = 100 wt% The blending ratio of

  In the polycarboxylic acid copolymer or salt (A) thereof, the ratio of the amount of monomer (II) to the amount of monomer (I) is preferably 10% by weight to 150% by weight, More preferably, it is 20 weight%-150 weight%, More preferably, it is 25 weight%-150 weight%. The ratio of the amount of monomer (III) to the amount of monomer (I) is preferably 1% to 70% by weight, more preferably 5% to 70% by weight, and still more preferably. Is 5% to 60% by weight. The ratio of the amount of monomer (IV) to the amount of monomer (I) is preferably 0% to 30% by weight, more preferably 0% to 20% by weight, and still more preferably. Is 0% to 10% by weight.

  Hereinafter, first, the monomer (I) will be described.

（式中、Ｒ¹は、炭素原子数２〜５のアルケニル基を表す。Ａ¹Ｏは、同一若しくは異なって、炭素原子数２〜１８のオキシアルキレン基を表す。ｎ１は、オキシアルキレン基の平均付加モル数であり、１〜１００の数を表す。Ｒ²は、水素原子または炭素原子数１〜３０の炭化水素基を表す。） Monomer (I) is a polyalkylene glycol monoalkenyl ether represented by the following general formula (1).

(In the formula, R ¹ represents an alkenyl group having 2 to 5 carbon atoms. A ¹ O is the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. N1 represents an oxyalkylene group. (The average number of moles added represents a number of 1 to 100. R ² represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.)

R ¹ in the general formula (1) represents an alkenyl group having 2 to 5 carbon atoms. The number of carbon atoms of the alkenyl group is preferably 3-5. Specific examples of R ¹ include, but are not limited to, an allyl group, a methallyl group, a residue of 3-methyl-3-buten-1-ol, and the like.

A ¹ O in the general formula (1) is the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. Examples of the oxyalkylene group include oxyethylene group (ethylene glycol), oxypropylene group (propylene glycol), oxybutylene group (butylene glycol), oxyethylene group (ethylene glycol), oxypropylene group (propylene glycol) ) Is preferred.

The above “same or different” means that when A ¹ O is contained in the general formula (1) (when n1 is 2 or more), each A ¹ O may be the same oxyalkylene group. Meaning that it may be different (two or more) oxyalkylene groups. In the case where a plurality of A ¹ O are contained in the general formula (1), 2 is selected from the group consisting of oxyethylene group (ethylene glycol), oxypropylene group (propylene glycol) and oxybutylene group (butylene glycol). Examples include a mixture of the above oxyalkylene groups, a mixture of oxyethylene groups (ethylene glycol) and oxypropylene groups (propylene glycol), or oxyethylene groups (ethylene glycol) and oxybutylene groups (butylene glycol). Is preferable, and an aspect in which an oxyethylene group (ethylene glycol) and an oxypropylene group (propylene glycol) are mixed is more preferable. In an embodiment in which different oxyalkylene groups are mixed, the addition of two or more oxyalkylene groups may be a block addition or a random addition.

  N1 in General formula (1) is the average addition mole number of an oxyalkylene group, and represents the number of 1-100. n1 is preferably 1 to 50, more preferably 5 to 50, and still more preferably 8 to 50. The average number of moles added means the average number of moles of alkylene glycol units added to 1 mole of monomer.

R ² in the general formula (1) represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. When the number of carbon atoms increases, the cement dispersibility of the cement admixture may not be sufficiently exhibited. Therefore, R ² is preferably a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. A hydrocarbon group of 1 to 5 is more preferable, and a hydrogen atom or a methyl group is most preferable.

  As a manufacturing method of monomer (I), the method of adding 1-80 mol of alkylene oxides to unsaturated alcohols, such as allyl alcohol, methallyl alcohol, 3-methyl-3-buten-1-ol, is mentioned, for example. It is done.

As the monomer (I), for example, (poly) ethylene glycol allyl ether, (poly) ethylene glycol methallyl ether, (poly) ethylene glycol 3-methyl-3-butenyl ether, (poly) ethylene (poly) propylene Glycol allyl ether, (poly) ethylene (poly) propylene glycol methallyl ether, (poly) ethylene (poly) propylene glycol 3-methyl-3-butenyl ether, (poly) ethylene (poly) butylene glycol allyl ether, (poly) Ethylene (poly) butylene glycol methallyl ether, (poly) ethylene (poly) butylene glycol 3-methyl-3-butenyl ether, methoxy (poly) ethylene glycol allyl ether, methoxy (poly) ethylene glycol methallyl ether , Methoxy (poly) ethylene glycol 3-methyl-3-butenyl ether, methoxy (poly) ethylene (poly) propylene glycol allyl ether, methoxy (poly) ethylene (poly) propylene glycol methallyl ether, methoxy (poly) ethylene ( Poly) propylene glycol 3-methyl-3-butenyl ether, methoxy (poly) ethylene (poly) butylene glycol allyl ether, methoxy (poly) ethylene (poly) butylene glycol methallyl ether, methoxy (poly) ethylene (poly) butylene glycol 3-methyl-3-butenyl ether is mentioned. As the monomer (I), one or more of these can be used, but it is preferable to use (poly) ethylene glycol (meth) allyl ether from the balance of hydrophilicity and hydrophobicity. Also in the specific examples of the monomer (I), the average added mole number of the oxyalkylene group (polyalkylene glycol) is preferably 1 to 70, more preferably 5 to 70, and 8 to 70. More preferably it is. In the present specification, “(poly)” means that the number of substituents immediately after that is one or two or more.
Monomer (I) may be one type or a combination of two or more types.

  Monomer (II) is represented by the following general formula (2).

（式中、Ｒ³、Ｒ⁴およびＲ⁵は、それぞれ独立に水素原子または炭素原子数１〜３のアルキル基を表す。ｍは、０〜２の数を表す。Ａ²Ｏは、同一若しくは異なって、炭素原子数２〜１８のオキシアルキレン基を表す。ｎ２は、オキシアルキレン基の平均付加モル数であり、１〜１００の数を表す。Ｘは、水素原子または炭素原子数１〜３０の炭化水素基を表す。）

(In the formula, R ³ , R ⁴ and R ⁵ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. M represents a number of 0 to ^2. A ² O is the same or Differently, it represents an oxyalkylene group having 2 to 18 carbon atoms, n2 is the average number of added moles of the oxyalkylene group, and represents a number of 1 to 100. X is a hydrogen atom or 1 to 30 carbon atoms. Represents a hydrocarbon group of

R ³ , R ⁴ and R ⁵ in the general formula (2) each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

A ² O in the general formula (2) is the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. Examples of the oxyalkylene group include oxyethylene group (ethylene glycol), oxypropylene group (propylene glycol), oxybutylene group (butylene glycol), oxyethylene group (ethylene glycol), oxypropylene group (propylene glycol) ) Is preferred.

The above “same or different” means that when A ² O is contained in the general formula (2) (when n2 is 2 or more), each A ² O may be the same oxyalkylene group. Meaning that it may be different (two or more) oxyalkylene groups. In the case where a plurality of A ² O are contained in the general formula (2), ² is selected from the group consisting of an oxyethylene group (ethylene glycol), an oxypropylene group (propylene glycol), and an oxybutylene group (butylene glycol). Examples include a mixture of the above oxyalkylene groups, a mixture of oxyethylene groups (ethylene glycol) and oxypropylene groups (propylene glycol), or oxyethylene groups (ethylene glycol) and oxybutylene groups (butylene glycol). Is preferable, and an aspect in which an oxyethylene group (ethylene glycol) and an oxypropylene group (propylene glycol) are mixed is more preferable. In an embodiment in which different oxyalkylene groups are mixed, the addition of two or more oxyalkylene groups may be a block addition or a random addition.

N2 in General formula (2) is the average addition mole number of an oxyalkylene group, and represents the number of 1-100. n2 is preferably 1 to 50, more preferably 5 to 50, and still more preferably 8 to 50. The average number of moles added means the average number of moles of alkylene glycol units added to 1 mole of monomer.
Monomer (II) may be a single monomer represented by the general formula (2) or a combination of two or more. Monomer (II) preferably includes a combination of two types of monomers (IIa) and (IIb) having different average addition mole numbers of oxyalkylene groups, and is preferably the combination. Thereby, even if it adds to a cement composition and passes for a long time, the outstanding fluidity | liquidity can be exhibited. The average added mole number n2a of the monomer (IIa) is preferably 1 to 5, and more preferably 1 to 3. The average added mole number n2b of the monomer (IIb) is preferably 6 to 100, more preferably 6 to 50.
When the monomer (II) is the monomers (IIa) and (IIb), the respective weight ratios (total is 100% by weight) are such that (IIa) / (IIb) is (1 to 99) / (99 to 1) is preferable, and (10 to 90) / (90 to 10) is more preferable.

  X in the general formula (2) represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. When the number of carbon atoms increases, the cement dispersibility of the cement admixture may not be sufficiently exhibited. Therefore, X is preferably hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, and is preferably a hydrogen atom or 1 carbon atom. It is more preferably a hydrocarbon group of ˜5, and most preferably a hydrogen atom or a methyl group.

  Examples of the monomer (II) include an unsaturated monocarboxylic acid such as (meth) acrylate (hereinafter, “(meth) acrylate” means “acrylate or methacrylate”), and (poly) ethylene glycol. , (Poly) ethylene (poly) propylene glycol, (poly) ethylene (poly) butylene glycol, methoxy (poly) ethylene glycol, methoxy (poly) ethylene (poly) propylene glycol, methoxy (poly) ethylene (poly) butylene glycol, etc. Of (poly) alkylene glycols. Specifically, for example, (poly) ethylene glycol (meth) acrylate, (poly) ethylene (poly) propylene glycol (meth) acrylate, (poly) ethylene (poly) butylene glycol (meth) acrylate, methoxy (poly) ethylene Examples include (poly) alkylene glycol (meth) acrylates such as glycol (meth) acrylate, methoxy (poly) ethylene (poly) propylene glycol (meth) acrylate, and methoxy (poly) ethylene (poly) butylene glycol (meth) acrylate. . As the monomer (II), one or a combination of two or more of these can be used, but (poly) alkylene glycol (meth) acrylate is preferably used, and (poly) ethylene glycol (meth) It is more preferable to use acrylate and methoxy (poly) ethylene glycol (meth) acrylate. The average number of added moles of (poly) alkylene glycol is preferably 1-50. When the monomer (IIa) is (poly) alkylene glycol, the number of added moles of (poly) alkylene glycol as the monomer (IIa) is preferably 1 to 5, and preferably 1 to 3. Is more preferable. When monomer (IIb) is (poly) alkylene glycol, the number of moles of (poly) alkylene glycol added as monomer (IIb) is preferably 6 to 100, and preferably 6 to 50. Is more preferable.

  Specific examples of the unsaturated monocarboxylic acid monomer (III) include carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and salts thereof (for example, monovalent metal salts and divalent metals). Salt, ammonium salt, organic amine salt). One or more of these can be used as the unsaturated monocarboxylic acid monomer (III). Among them, acrylic acid or a salt thereof, methacrylic acid or a salt thereof is preferable, and acrylic acid or a salt thereof When two types of salt and methacrylic acid or a salt thereof are used in combination, the ratio (total 100% by weight) when using acrylic acid or a salt thereof (III-1) and methacrylic acid or a salt thereof (III-2) is (III-1) / (III-2) is (1% to 50%) / (50% to 99%). Monomer (III) may be one type or a combination of two or more types.

  Monomer (IV) is not particularly limited as long as it is a monomer copolymerizable with one or more monomers selected from the group consisting of monomers (I), (II) and (III) . The monomer (IV) does not include the monomer (I), the monomer (II), and the monomer (III).

  Examples of the monomer (IV) include the following, and one or more of these can be used;

で示されるジアリルビスフェノール類、例えば４，４’−ジヒドロキシジフェニルプロパン、４，４’−ジヒドロキシジフェニルメタン、４，４’−ジヒドロキシジフェニルスルホンの３および３’位アリル置換物； Formula (IV-1):

Diallyl bisphenols, such as 4,4′-dihydroxydiphenylpropane, 4,4′-dihydroxydiphenylmethane, and 3 and 3 ′ allyl substitutes of 4,4′-dihydroxydiphenylsulfone;

で示されるモノアリルビスフェノール類、例えば４，４’−ジヒドロキシジフェニルプロパン、４，４’−ジヒドロキシジフェニルメタン、４，４’−ジヒドロキシジフェニルスルホンの３位アリル置換物； General formula (IV-2):

Monoallyl bisphenols represented by the formula: for example, 4,4'-dihydroxydiphenylpropane, 4,4'-dihydroxydiphenylmethane, 3-position allyl substitute of 4,4'-dihydroxydiphenylsulfone;

で示されるアリルフェノール； General formula (IV-3):

An allylphenol;

Half esters and diesters of unsaturated dicarboxylic acids such as maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid and alcohols having 1 to 30 carbon atoms;
Half amides and diamides of the above unsaturated dicarboxylic acids and amines having 1 to 30 carbon atoms;
Half esters and diesters of an alkyl (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 the unsaturated dicarboxylic acid;
Half esters and diesters of the above unsaturated dicarboxylic acids and glycols having 2 to 18 carbon atoms or polyalkylene glycols having 2 to 500 addition moles of these glycols;
Half amides of maleamic acid and glycols having 2 to 18 carbon atoms or polyalkylene glycols having 2 to 500 addition moles of these glycols;
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 an alcohol having 1 to 30 carbon atoms and an unsaturated monocarboxylic acid such as (meth) acrylic acid; Of alkylene oxides having 2 to 18 carbon atoms to unsaturated monocarboxylic acids such as (meth) acrylic acid, such as (poly) ethylene glycol monomethacrylate, (poly) propylene glycol monomethacrylate, (poly) butylene glycol monomethacrylate 1-500 mole adducts;

(Poly) alkylene glycols such as triethylene glycol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, (poly) ethylene glycol (poly) propylene glycol di (meth) acrylate, etc. Di (meth) acrylates;
Polyfunctional (meth) acrylates such as hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane di (meth) acrylate;
(Poly) alkylene glycol dimaleates such as triethylene glycol dimaleate and polyethylene glycol dimaleate;
Vinyl sulfonate, (meth) allyl sulfonate, 2- (meth) acryloxyethyl sulfonate, 3- (meth) acryloxypropyl sulfonate, 3- (meth) acryloxy-2-hydroxypropyl sulfonate, 3- (meth) acryloxy-2 -Hydroxypropylsulfophenyl ether, 3- (meth) acryloxy-2-hydroxypropyloxysulfobenzoate, 4- (meth) acryloxybutylsulfonate, (meth) acrylamidomethylsulfonic acid, (meth) acrylamidoethylsulfonic acid, 2- Unsaturated sulfonic acids such as methylpropanesulfonic acid (meth) acrylamide and styrenesulfonic acid, and monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts thereof;
Amides of unsaturated monocarboxylic acids such as methyl (meth) acrylamide and amines having 1 to 30 carbon atoms;
Vinyl aromatics such as styrene, α-methylstyrene, vinyltoluene, p-methylstyrene;
Alkanediol mono (meth) acrylates such as 1,4-butanediol mono (meth) acrylate, 1,5-pentanediol mono (meth) acrylate, 1,6-hexanediol mono (meth) acrylate;
Dienes such as butadiene, isoprene, 2-methyl-1,3-butadiene, 2-chloro-1,3-butadiene;

Unsaturated amides such as (meth) acrylamide, (meth) acrylic alkylamide, N-methylol (meth) acrylamide, N, N-dimethyl (meth) acrylamide;
Unsaturated cyanides such as (meth) acrylonitrile, α-chloroacrylonitrile;
Unsaturated esters such as vinyl acetate and vinyl propionate; aminoethyl (meth) acrylate, methylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, (meth ) Unsaturated amines such as dibutylaminoethyl acrylate and vinylpyridine;
Divinyl aromatics such as divinylbenzene; cyanurates such as triallyl cyanurate;
Allyls such as (meth) allyl alcohol and glycidyl (meth) allyl ether;
Vinyl ethers or allyl ethers such as methoxypolyethylene glycol monovinyl ether, polyethylene glycol monovinyl ether, methoxypolyethylene glycol mono (meth) allyl ether, polyethylene glycol mono (meth) allyl ether; and
Polydimethylsiloxanepropylaminomaleamic acid, polydimethylsiloxaneaminopropylaminomaleamic acid, polydimethylsiloxane-bis- (propylaminomaleamic acid), polydimethylsiloxane-bis- (dipropylaminomaleamic acid), polydimethyl Siloxane- (1-propyl-3-acrylate), polydimethylsiloxane- (1-propyl-3-methacrylate), polydimethylsiloxane-bis- (1-propyl-3-acrylate), polydimethylsiloxane-bis- (1 Siloxane derivatives such as -propyl-3-methacrylate).

  In obtaining a polycarboxylic acid copolymer or a salt thereof (A), if necessary, other than monomer (I), monomer (II), monomer (III) and monomer (IV) These monomers may be used.

  In the present invention, the polycarboxylic acid copolymer or salt (A) thereof can be produced by copolymerizing each predetermined monomer by a known method. Examples of the method include polymerization methods such as polymerization in a solvent and bulk polymerization.

  Examples of the solvent used in the polymerization in the solvent include water; lower alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol; aromatic hydrocarbons such as benzene, toluene and xylene; fats such as cyclohexane and n-hexane. Group hydrocarbons; esters such as ethyl acetate; ketones such as acetone and methyl ethyl ketone. From the viewpoint of solubility of the raw material monomer and the resulting copolymer, it is preferable to use one or more selected from the group consisting of water and lower alcohols, and among these, water is more preferable.

  When copolymerization is performed in a solvent, each monomer and a polymerization initiator may be continuously dropped into each reaction vessel, or a mixture of each monomer and a polymerization initiator are dropped continuously into each reaction vessel. Also good. Alternatively, a solvent may be charged into the reaction vessel, and a mixture of the monomer and the solvent and a polymerization initiator solution may be continuously dropped into the reaction vessel, or a part or all of the monomer may be charged into the reaction vessel and polymerized. The initiator may be continuously dropped.

  The polymerization initiator that can be used for copolymerization is, for example, persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate; and water-soluble such as t-butyl hydroperoxide. An organic peroxide is mentioned. In this case, an accelerator such as sodium hydrogen sulfite and a mol salt can be used in combination. When copolymerization is performed in a solvent such as a lower alcohol, aromatic hydrocarbon, aliphatic hydrocarbon, ester or ketone, for example, peroxides such as benzoyl peroxide and lauryl peroxide; cumene peroxide Hydroperoxides such as: aromatic azo compounds such as azobisisobutyronitrile can be used as the polymerization initiator. In this case, an accelerator such as an amine compound can be used in combination. Furthermore, when copolymerization is carried out in a water-lower alcohol mixed solvent, it can be used by appropriately selecting from the aforementioned polymerization initiator or a combination of a polymerization initiator and an accelerator. The polymerization temperature varies depending on the polymerization conditions such as the solvent used and the type of polymerization initiator, but is usually in the range of 50 to 120 ° C.

  In the copolymerization, the molecular weight can be adjusted using a chain transfer agent as required. Examples of the chain transfer agent used include mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, octyl thioglycolate, and 2-mercaptoethanesulfonic acid. Known thiol compounds; phosphorous acid, hypophosphorous acid, and salts thereof (sodium hypophosphite, potassium hypophosphite, etc.), sulfurous acid, hydrogen sulfite, dithionite, metabisulfite, and the like Lower oxides of salts (sodium sulfite, potassium sulfite, sodium hydrogen sulfite, potassium hydrogen sulfite, sodium dithionite, potassium dithionite, sodium metabisulfite, potassium metabisulfite, etc.) and salts thereof; It is done. These may be used alone or in combination of two or more. Furthermore, in order to adjust the molecular weight of the polycarboxylic acid copolymer or its salt (A), it is also effective to use a monomer (V) having a higher chain transfer property as a monomer for obtaining each. It is. Examples of the monomer (V) having a high chain transfer property include (meth) allylsulfonic acid (salt) monomers. The blending ratio of the monomer (V) is usually 20% by weight or less and preferably 10% by weight or less in the polycarboxylic acid copolymer or the salt (A) thereof. In addition, the blending ratio of (A) is the blending ratio of the monomer (I) + the blending ratio derived from the monomer (II) + the blending ratio of the monomer (III) + the monomer (IV). The blending ratio is 100% by weight.

When copolymerization is carried out in an aqueous solvent when obtaining a copolymer, the pH during polymerization usually becomes strongly acidic due to the influence of a monomer having an unsaturated bond, but this may be adjusted to an appropriate pH. . If it is necessary to adjust the pH during polymerization, adjust the pH using an acidic substance such as phosphoric acid, sulfuric acid, nitric acid, alkylphosphoric acid, alkylsulfuric acid, alkylsulfonic acid, or (alkyl) benzenesulfonic acid. Can do. Among these acidic substances, it is preferable to use phosphoric acid because it has a pH buffering action. However, in order to eliminate the instability of the ester bond of the ester monomer, it is preferable to perform the polymerization at pH 2-7. Moreover, although there is no limitation in particular in the alkaline substance which can be used for adjustment of pH, alkaline substances, such as NaOH and Ca (OH) _2, are common. The pH adjustment may be performed on the monomer before polymerization or may be performed on the copolymer solution after polymerization. In addition, these may be subjected to polymerization by adding a part of an alkaline substance before polymerization, and then the pH of the copolymer may be further adjusted.

  The weight average molecular weight of the polycarboxylic acid copolymer or salt (A) is preferably 10,000 to 50,000. When the weight average molecular weight is less than 10,000, the cement dispersibility of the cement admixture is not sufficiently exhibited, and the water reduction rate exceeding the AE water reducing agent such as lignin sulfonic acid type or oxycarboxylic acid type cannot be obtained. Or the workability may not be improved, and the intended effect as a cement admixture may not be sufficiently exhibited. On the other hand, if the weight average molecular weight exceeds 50,000, the cohesive action is exhibited and the workability may be reduced.

  The molecular weight distribution (Mw / Mn) of the polycarboxylic acid copolymer or salt (A) is preferably in the range of 1.2 to 3.0.

  In addition, the weight average molecular weight in this invention can be measured by the well-known method converted into polyethyleneglycol by gel permeation chromatography (GPC).

Although there is no limitation in particular as measurement conditions of GPC, the following conditions can be mentioned as an example. The weight average molecular weight in the latter examples is a value measured under these conditions.
Measuring device; column used by Tosoh; Shodex Column OH-pak SB-806HQ, SB-804HQ, SB-802.5HQ
Eluent: 0.05 mM sodium nitrate / acetonitrile 8/2 (v / v)
Standard material: Polyethylene glycol (Tosoh, GL Science)
Detector: differential refractometer (manufactured by Tosoh)
Calibration curve; polyethylene glycol standard

  The cement admixture of the present invention may contain one type of polycarboxylic acid copolymer or salt (A) thereof, or may contain two or more types.

  The cement admixture of the present invention may further contain other components as necessary. Other components include a (poly) alkylene glycol alkenyl ether monomer (B), a water-soluble polyalkylene glycol (C) in which both terminal groups are hydrogen atoms, and a polycarboxylic acid copolymer or a salt thereof ( And D) and polycarboxylic acid copolymers or salts (E) thereof.

  When the cement admixture of the present invention contains the (poly) alkylene glycol alkenyl ether monomer (B), the resulting cement admixture can reduce the viscosity of the cement composition and improve workability. It is preferable in that it can be performed.

  The content ratio of the (poly) alkylene glycol alkenyl ether monomer (B) in the cement admixture of the present invention is 90% by weight or less based on the polycarboxylic acid copolymer or salt (A) thereof. Is more preferable, 80% by weight or less, more preferably 60% by weight or less. If it exceeds 90% by weight, the dispersibility of the cement may not be sufficiently exhibited, which is not preferable. Moreover, in order to obtain the workability improvement effect by the (poly) alkylene glycol alkenyl ether monomer (B), the lower limit is usually 1% by weight or more.

  Specific examples and preferred examples of the (poly) alkylene glycol alkenyl ether monomer (B) are the same as the specific examples and preferred examples of the compound represented by the general formula (1) as the monomer (I). is there. The (poly) alkylene glycol alkenyl ether monomer (B) may be the same as or different from the monomer (I). Furthermore, as a monomer (B), 1 type may be used or 2 or more types may be used.

  The (poly) alkylene glycol alkenyl ether monomer (B) may be blended separately from the polycarboxylic acid copolymer or salt (A) thereof. Alternatively, it may exist as a residue that is not copolymerized in the production of the polycarboxylic acid copolymer or its salt (A), which is produced as follows, for example, without being separately blended. . The monomer (I) used as a raw material when the polycarboxylic acid copolymer or its salt (A) is produced remains in the polycarboxylic acid copolymer or its salt (A). By stopping the polymerization reaction at the time, a composition containing the (poly) alkylene glycol alkenyl ether monomer (B) and the polycarboxylic acid copolymer or salt (A) thereof can be obtained. The point at which the polymerization reaction is stopped can be determined according to the blending ratio of the (poly) alkylene glycol alkenyl ether monomer (B) to the polycarboxylic acid copolymer or salt (A) thereof. That is, the residual amount of the (poly) alkylene glycol alkenyl ether monomer (B) with respect to the polycarboxylic acid copolymer or salt (A) is preferably 80% by weight or less, more preferably 60% by weight or less. At this point, the polymerization reaction is stopped. The polymerization reaction is stopped when the lower limit of the residual amount is usually 1% by weight or more.

  As described above, the cement admixture of the present invention may further contain a water-soluble polyalkylene glycol (C) in which both terminal groups are hydrogen atoms. That both terminal groups are hydrogen atoms means that the terminal of the main chain is a hydrogen atom, that is, the terminal of the main chain is not substituted with a substituent other than a hydrogen atom. Water-soluble means soluble in water. The blending ratio of the water-soluble polyalkylene glycol (C) in which both terminal groups are hydrogen atoms is usually 0.01 to 5% by weight based on the polycarboxylic acid copolymer or salt (A) thereof. The water-soluble polyalkylene glycol (C) whose both terminal groups are hydrogen atoms may be blended separately from the polycarboxylic acid copolymer or salt (A) thereof. On the other hand, a water-soluble polyalkylene glycol in which both terminal groups are hydrogen atoms is produced as a by-product during the production of the monomer (I) which is a raw material of the polycarboxylic acid copolymer or salt (A) thereof. You may use this. The proportion of the water-soluble polyalkylene glycol (C) in the monomer (I) is usually about 0.02 wt% to 10 wt%. The weight average molecular weight of the water-soluble polyalkylene glycol (C) in which both terminal groups are hydrogen atoms is preferably 300 to 5,000.

  Specific examples of the water-soluble polyalkylene glycol (C) in which both terminal groups are hydrogen atoms include polyethylene glycol, polypropylene glycol, polyethylene polypropylene glycol, polyethylene polybutylene glycol, and the like, and polyethylene glycol is preferred. The water-soluble polyalkylene glycol (C) whose both terminal groups are hydrogen atoms can be used alone or in combination of two or more.

  The polycarboxylic acid copolymer or the salt (D) thereof includes a monomer (I) represented by the general formula (1), an unsaturated monocarboxylic acid monomer (III), and (I) and (III). ) And other monomers (VI) copolymerizable with polycarboxylic acid copolymers or salts thereof. The polycarboxylic acid copolymer or its salt (D) is different from the polycarboxylic acid copolymer or its salts (A) and (E) in that the monomer (II) is not copolymerized. Specific examples and preferred examples of the monomer (I) and the monomer (III) are specific examples and preferred examples of the monomer (I) of the polycarboxylic acid copolymer or its salt (A). The same. The monomer (VI) may be copolymerizable with the monomers (I) and (III), may be copolymerizable with the monomer (II), and the monomers (I) to (III) It may be copolymerizable with other monomers. Specific examples and preferred examples of the monomer (VI) are the same as the specific examples and preferred examples of the monomer (IV) of the polycarboxylic acid copolymer or its salt (A). The method for producing the polycarboxylic acid copolymer or its salt (D) is also as described in the column of the polycarboxylic acid copolymer or its salt (A).

  The blending ratio of each monomer when obtaining the polycarboxylic acid copolymer or salt (D) is as follows. The blending ratio of the monomer (I) is preferably 40% by weight to 97% by weight, more preferably 50% by weight to 97% by weight, and still more preferably 60% by weight to 97% by weight. The blending ratio of the monomer (III) is preferably 1% by weight to 60% by weight, more preferably 1% by weight to 50% by weight, and still more preferably 1% by weight to 40% by weight. The blending ratio of the monomer (VI) is preferably 0% by weight to 50% by weight, more preferably 0% by weight to 40% by weight, and still more preferably 0% by weight to 30% by weight.

  In the polycarboxylic acid copolymer or salt (D) thereof, the ratio of the amount of monomer (III) to the amount of monomer (I) is preferably 1% by weight to 70% by weight, More preferably, it is 5 weight%-70 weight%, More preferably, it is 5 weight%-60 weight%. The ratio of the amount of monomer (VI) to the amount of monomer (I) is preferably 0% to 50% by weight, more preferably 0% to 40% by weight, and still more preferably. Is 0% to 30% by weight.

  By blending the polycarboxylic acid copolymer or its salt (D), better slump retention can be obtained. When the polycarboxylic acid copolymer or its salt (D) is blended, its content is 1% by weight to 99% by weight with respect to the polycarboxylic acid copolymer or its salt (A). It is preferably 5% to 95% by weight, more preferably 10% to 90% by weight.

  The polycarboxylic acid copolymer or the salt (E) thereof includes a monomer (II) represented by the general formula (2), an unsaturated monocarboxylic acid monomer (III), and (II) and (III). ) And other monomers (VII) copolymerizable with a polycarboxylic acid copolymer or a salt thereof. The polycarboxylic acid copolymer or salt (E) thereof differs from the polycarboxylic acid copolymer or salts (A) and (D) thereof in that the monomer (I) is not copolymerized. Specific examples and preferred examples of the monomer (II) and the monomer (III) in the polycarboxylic acid copolymer or salt (E) thereof are polycarboxylic acid copolymer or salt (A). ) Are the same as the specific examples and preferred examples of the monomer (II). The monomer (VII) may be copolymerizable with the monomers (II) and (III), may be copolymerizable with the monomer (II), and the monomers (I) to (III) It may be copolymerizable with other monomers. Specific examples and preferred examples of the monomer (VII) are the same as the specific examples and preferred examples of the monomer (IV) of the polycarboxylic acid copolymer or its salt (A). The method for producing the polycarboxylic acid copolymer or its salt (E) is also as described in the column of the polycarboxylic acid copolymer or its salt (A).

  The blending ratio of each monomer when obtaining the polycarboxylic acid copolymer or salt (E) is as follows. The blending ratio of the monomer (II) is preferably 40% by weight to 97% by weight, more preferably 50% by weight to 97% by weight, and still more preferably 60% by weight to 97% by weight. The blending ratio of the monomer (III) is preferably 1% by weight to 60% by weight, more preferably 1% by weight to 50% by weight, and still more preferably 1% by weight to 40% by weight. The blending ratio of the monomer (VII) is preferably 0% to 50% by weight, more preferably 0% to 40% by weight, and still more preferably 0% to 30% by weight.

  In the polycarboxylic acid copolymer or salt (E) thereof, the ratio of the amount of monomer (III) to the amount of monomer (II) is preferably 1% by weight to 70% by weight, More preferably, it is 5 weight%-70 weight%, More preferably, it is 5 weight%-60 weight%. The ratio of the amount of monomer (VII) to the amount of monomer (II) is preferably 0% to 50% by weight, more preferably 0% to 40% by weight, still more preferably. Is 0% to 30% by weight.

  By blending the polycarboxylic acid copolymer or its salt (E), better slump retention can be obtained. When the polycarboxylic acid copolymer or its salt (E) is blended, the content is 1% by weight to 99% by weight with respect to the polycarboxylic acid copolymer or its salt (A). It is preferably 5% to 95% by weight, more preferably 10% to 90% by weight.

  In the cement admixture of the present invention, the form of component (A) is not limited, component (A) may be included as it is, a solution in which component (A) is dissolved in a solvent, or a dispersion in which component (A) is dispersed. Alternatively, it may be formulated as a suspended suspension. In addition, the components (B), (C), (D), and (E) that are included as necessary may also be included in the solution, dispersion, or suspension of the component (A). The dispersion may contain a commercially available dispersant. When the cement admixture of the present invention contains component (D) and / or component (E), a solution, dispersion or suspension of component (A) (and component (B) and / or (C)); Separately prepare a component (D) and / or component (E) dissolved in a solvent, a dispersed dispersion, and a suspended suspension, and blend them to prepare a cement admixture. May be.

  The cement admixture of the present invention can be used in the form of an aqueous solution or in the form of powder after drying. The time when the cement admixture is added to other components constituting the cement composition and hydraulic materials other than the cement composition may be during use of the cement composition. In addition, the cement admixture of the present invention in a powdered form is previously mixed with components other than water constituting the cement composition, such as cement powder, dry mortar, plastering, floor finishing, grout, etc. In this case, it can also be used as a premix product to which water is added.

  The cement admixture of the present invention can be added to a hydraulic material such as cement and used as a cement composition such as cement paste, mortar, concrete, or plaster.

  The cement composition of this invention should just contain a cement admixture, and the hydraulic material to combine is not specifically limited. Examples of the hydraulic material include cement, gypsum (semihydrate gypsum, dihydrate gypsum, etc.), and dolomite. The most common hydraulic material is cement.

  The cement is not particularly limited. For example, Portland cement (ordinary, early strength, very early strength, moderate heat, sulfate-resistant and low alkali type of each), 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 mixed low exothermic blast furnace cement, belite High-content cement), ultra-high-strength cement, cement-based solidified material, eco-cement (cement produced using at least one of municipal waste incineration ash and sewage sludge incineration ash). Blast furnace slag, fly ash, cinder ash, clinker ash, husk ash, silica fume, silica powder, limestone powder and other fine powder, gypsum and the like may be added to the cement.

  Moreover, the cement composition may contain the aggregate. The aggregate may be either a fine aggregate or a coarse aggregate. Examples of aggregates include sand, gravel, crushed stone; granulated slag; recycled aggregate, etc .; siliceous, clay, zircon, high alumina, silicon carbide, graphite, chrome, chromic, magnesia Fireproof aggregates such as

  There is no particular limitation on the blending ratio of the cement admixture in the cement composition. For example, when the cement composition is mortar or concrete, the addition amount (blending amount) of the polycarboxylic acid copolymer or salt (A) contained in the cement admixture is based on the total weight of the cement. 0.01 to 5.0% by weight, preferably 0.02 to 2.0% by weight, more preferably 0.05 to 1.0% by weight. By using this added amount, the obtained cement composition has various preferable effects such as a reduction in unit water amount, an increase in strength, and an improvement in durability. If the blending ratio is less than 0.01% by weight, the resulting cement composition may not be sufficient in terms of performance, and conversely, even if a large amount exceeding 5.0% by weight is used, the effect is substantially reduced. There is a risk that it will hit a peak and be disadvantageous in terms of economy.

  The cement composition is effective as, for example, ready mixed concrete, concrete for concrete secondary products (precast concrete), concrete for centrifugal molding, concrete for vibration compaction, steam-cured concrete, shotcrete, and the like. . Furthermore, 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-leveling material It is also effective as mortar or concrete that requires high fluidity such as.

  The cement admixture of the present invention can be used as a cement dispersant as it is. Still other cement dispersants, water-soluble polymers, polymer emulsions, air entrainers, cement wetting agents, swelling agents, waterproofing agents, retarders, thickeners, flocculants, drying shrinkage reducing agents, strength enhancers, effects It can also be used in combination with known additives for concrete such as accelerators, antifoaming agents, AE agents, and other surfactants. These may be used alone or in combination of two or more.

  The present invention will be described more specifically with reference to the following examples, but the present invention is not limited thereto. In the examples, unless otherwise indicated, “%” means “% by weight” and “parts” means “parts by weight”.

<Production Example 1>
148 parts of water and 124 parts of polyethylene glycol monoallyl ether (average number of moles of added ethylene oxide of 30) are charged in a glass reaction vessel equipped with a thermometer, a stirring device, a reflux device, a nitrogen introduction tube and a dropping device and stirred. The reaction vessel was purged with nitrogen below, and the temperature was raised to 80 ° C. in a nitrogen atmosphere. Then, 6 parts of methacrylic acid, 3 parts of acrylic acid, 63 parts of methoxypolyethylene glycol methacrylate (average number of added moles of ethylene oxide 13), 165 parts of water, a monomer aqueous solution, 3 parts of ammonium persulfate and 47 parts of water The mixed solution was continuously dropped into a reaction vessel maintained at 80 ° C. for 2 hours each. Furthermore, the aqueous solution of the copolymer was obtained by making it react for 1 hour in the state hold | maintained at 100 degreeC. The content of polyethylene glycol allyl ether in the copolymer was 25% by weight, and the content of water-soluble polyethylene glycol in which both terminal groups were hydrogen atoms was 0.7% by weight. This solution was adjusted to pH 7 with 30% NaOH aqueous solution. The copolymer in the liquid was a copolymer (A-1) (weight average molecular weight 32,000, Mw / Mn 1.9).

<Production Example 2>
148 parts of water, 84 parts of polyethylene glycol monoallyl ether (average number of moles of ethylene oxide added 20) in a glass reaction vessel equipped with a thermometer, a stirring device, a reflux device, a nitrogen introducing tube and a dropping device, and 4,4 2 parts of the compound in which the 3 and 3 'positions of' -dihydroxydiphenylsulfone were allyl-substituted were charged, the reaction vessel was purged with nitrogen under stirring, and the temperature was raised to 80 ° C under a nitrogen atmosphere. Then, 6 parts of methacrylic acid, 3 parts of acrylic acid, 63 parts of methoxypolyethylene glycol methacrylate (average number of added moles of ethylene oxide 13), 165 parts of water, a monomer aqueous solution, 3 parts of ammonium persulfate and 47 parts of water The mixed solution was continuously dropped into a reaction vessel maintained at 80 ° C. for 2 hours each. Furthermore, the aqueous solution of the copolymer was obtained by making it react for 1 hour in the state hold | maintained at 100 degreeC. The content of polyethylene glycol allyl ether in the copolymer was 20% by weight, and the content of water-soluble polyethylene glycol in which both terminal groups were hydrogen atoms was 0.5% by weight. This solution was adjusted to pH 7 with 30% NaOH aqueous solution. The copolymer in the liquid was a copolymer (A-2) (weight average molecular weight 30,000, Mw / Mn 1.8).

<Production Example 3>
148 parts of water and 45 parts of polyethylene glycol monoallyl ether (average number of moles of ethylene oxide added 10) are charged into a glass reaction vessel equipped with a thermometer, stirring device, refluxing device, nitrogen introducing tube and dropping device, and stirred. The reaction vessel was purged with nitrogen below, and the temperature was raised to 80 ° C. in a nitrogen atmosphere. Thereafter, an aqueous monomer solution in which 9 parts of methacrylic acid, 63 parts of methoxypolyethylene glycol methacrylate (average number of added moles of ethylene oxide of 13) and 165 parts of water were mixed, and a mixed solution of 3 parts of ammonium persulfate and 47 parts of water, It was continuously dropped into a reaction vessel maintained at 80 ° C. for 2 hours each. Furthermore, the aqueous solution of the copolymer was obtained by making it react for 1 hour in the state hold | maintained at 100 degreeC. The content of polyethylene glycol allyl ether in the copolymer was 15% by weight, and the content of water-soluble polyethylene glycol in which both terminal groups were hydrogen atoms was 0.7% by weight. This solution was adjusted to pH 7 with 30% NaOH aqueous solution. The copolymer in the liquid was a copolymer (A-3) (weight average molecular weight 28,300, Mw / Mn1.8).

<Production Example 4>
148 parts of water and 124 parts of polyethylene glycol monoallyl ether (average number of added moles of ethylene oxide) of 124 parts are charged into a glass reaction vessel equipped with a thermometer, a stirring device, a reflux device, a nitrogen introducing tube and a dropping device, and stirred. The reaction vessel was purged with nitrogen below, and the temperature was raised to 80 ° C. in a nitrogen atmosphere. Thereafter, an aqueous monomer solution in which 9 parts of methacrylic acid, 73 parts of methoxypolyethylene glycol methacrylate (average number of added moles of ethylene oxide of 30) and 165 parts of water were mixed, and a mixed liquid of 3 parts of ammonium persulfate and 47 parts of water, It was continuously dropped into a reaction vessel maintained at 80 ° C. for 2 hours each. Furthermore, the aqueous solution of the copolymer was obtained by making it react for 1 hour in the state hold | maintained at 100 degreeC. The content of polyethylene glycol allyl ether in the copolymer was 25% by weight, and the content of water-soluble polyethylene glycol in which both terminal groups were hydrogen atoms was 0.6% by weight. This solution was adjusted to pH 7 with 30% NaOH aqueous solution. The copolymer in the liquid was a copolymer (A-4) (weight average molecular weight 31,000, Mw / Mn 1.9).

<Production Example 5>
148 parts of water in a glass reaction vessel equipped with a thermometer, a stirrer, a reflux device, a nitrogen introduction tube and a dropping device, and an ethylene oxide adduct of 3-methyl-3-buten-1-ol (average addition of ethylene oxide) The reaction vessel was purged with nitrogen under stirring and heated to 80 ° C. under a nitrogen atmosphere. Then, 6 parts of methacrylic acid, 3 parts of acrylic acid, 73 parts of methoxypolyethylene glycol methacrylate (average number of added moles of ethylene oxide 18), 165 parts of water, a monomer aqueous solution, 3 parts of ammonium persulfate and 47 parts of water The mixed solution was continuously dropped into a reaction vessel maintained at 80 ° C. for 2 hours each. Furthermore, the aqueous solution of the copolymer was obtained by making it react for 1 hour in the state hold | maintained at 100 degreeC. The content of ethylene oxide adduct of 3-methyl-3-buten-1-ol with respect to the copolymer is 10% by weight, and the content of water-soluble polyethylene glycol in which both terminal groups are hydrogen atoms is 0. It was 7% by weight. This solution was adjusted to pH 7 with 30% NaOH aqueous solution. The copolymer in the liquid was a copolymer (A-5) (weight average molecular weight 27,000, Mw / Mn 1.8).

<Production Example 6>
148 parts of water and 45 parts of polyethylene glycol monoallyl ether (average number of moles of ethylene oxide added 10) are charged into a glass reaction vessel equipped with a thermometer, stirring device, refluxing device, nitrogen introducing tube and dropping device, and stirred. The reaction vessel was purged with nitrogen below, and the temperature was raised to 80 ° C. in a nitrogen atmosphere. Then, 2 parts of methacrylic acid, 17 parts of methoxypolyethylene glycol methacrylate (average number of moles of ethylene oxide added 13), 39 parts of ethylene glycol acrylate (average number of moles of added ethylene oxide 1) and 165 parts of water An aqueous solution and a mixed solution of 3 parts of ammonium persulfate and 47 parts of water were continuously dropped into a reaction vessel maintained at 80 ° C. for 2 hours each. Furthermore, the aqueous solution of the copolymer was obtained by making it react for 1 hour in the state hold | maintained at 100 degreeC. The content of polyethylene glycol allyl ether in the copolymer was 10% by weight, and the content of water-soluble polyethylene glycol in which both terminal groups were hydrogen atoms was 0.3% by weight. This solution was adjusted to pH 4 with 30% NaOH aqueous solution. The copolymer in the liquid was a copolymer (A-6) (weight average molecular weight 14,300, Mw / Mn1.8).

<Production Example 7>
148 parts of water in a glass reaction vessel equipped with a thermometer, a stirrer, a reflux device, a nitrogen introduction tube and a dropping device, and an ethylene oxide adduct of 3-methyl-3-buten-1-ol (average addition of ethylene oxide) The reaction vessel was purged with nitrogen under stirring and heated to 80 ° C. under a nitrogen atmosphere. Thereafter, 2 parts of methacrylic acid, 17 parts of methoxypolyethylene glycol methacrylate (average number of added moles of ethylene oxide 19), 39 parts of ethylene glycol acrylate (average number of added moles of ethylene oxide 1), and 165 parts of water were mixed. The monomer aqueous solution and a mixed solution of 3 parts of ammonium persulfate and 47 parts of water were continuously added dropwise to a reaction vessel maintained at 80 ° C. for 2 hours each. Furthermore, the aqueous solution of the copolymer was obtained by making it react for 1 hour in the state hold | maintained at 100 degreeC. The content of ethylene oxide adduct of 3-methyl-3-buten-1-ol with respect to the copolymer is 8% by weight, and the content of water-soluble polyethylene glycol in which both terminal groups are hydrogen atoms is 0. It was 3% by weight. This solution was adjusted to pH 4 with 30% NaOH aqueous solution. The copolymer in the liquid was a copolymer (A-7) (weight average molecular weight 17,800, Mw / Mn 2.0).

<Production Example 8>
148 parts of water and 45 parts of polyethylene glycol monoallyl ether (average number of moles of ethylene oxide added 10) are charged into a glass reaction vessel equipped with a thermometer, stirring device, refluxing device, nitrogen introducing tube and dropping device, and stirred. The reaction vessel was purged with nitrogen below, and the temperature was raised to 80 ° C. in a nitrogen atmosphere. Thereafter, 2 parts of methacrylic acid, 17 parts of methoxypolyethylene glycol methacrylate (average number of moles of ethylene oxide added 13), 15 parts of polyethylene glycol acrylate (average number of moles of added ethylene oxide 3), and 165 parts of water were mixed. The monomer aqueous solution and a mixed solution of 3 parts of ammonium persulfate and 47 parts of water were continuously added dropwise to a reaction vessel maintained at 80 ° C. for 2 hours each. Furthermore, the aqueous solution of the copolymer was obtained by making it react for 1 hour in the state hold | maintained at 100 degreeC. The content of polyethylene glycol allyl ether in the copolymer was 10% by weight, and the content of water-soluble polyethylene glycol in which both terminal groups were hydrogen atoms was 0.2% by weight. This solution was adjusted to pH 4 with 30% NaOH aqueous solution. The copolymer in the liquid was a copolymer (A-8) (weight average molecular weight 15,200, Mw / Mn 1.5).

<Production Example 9>
148 parts of water and 45 parts of polyethylene glycol monoallyl ether (average number of moles of ethylene oxide added 10) are charged into a glass reaction vessel equipped with a thermometer, stirring device, refluxing device, nitrogen introducing tube and dropping device, and stirred. The reaction vessel was purged with nitrogen below, and the temperature was raised to 80 ° C. in a nitrogen atmosphere. Thereafter, 2 parts of methacrylic acid, 0.2 part of acrylic acid, 17 parts of methoxypolyethylene glycol methacrylate (average number of moles of ethylene oxide added 13), 39 parts of ethylene glycol acrylate (average number of moles of added ethylene oxide 1), And the monomer aqueous solution which mixed 165 parts of water, and the liquid mixture of 3 parts of ammonium persulfate, and 47 parts of water were continuously dripped at reaction container hold | maintained at 80 degreeC in 2 hours, respectively. Furthermore, the aqueous solution of the copolymer was obtained by making it react for 1 hour in the state hold | maintained at 100 degreeC. The content of polyethylene glycol allyl ether in the copolymer was 10% by weight, and the content of water-soluble polyethylene glycol in which both terminal groups were hydrogen atoms was 0.7% by weight. This solution was adjusted to pH 4 with 30% NaOH aqueous solution. The copolymer in the liquid was a copolymer (A-9) (weight average molecular weight 13,500, Mw / Mn 2.0).

<Production Example 10>
148 parts of water and 45 parts of polyethylene glycol monoallyl ether (average number of added moles of ethylene oxide of 19) are charged in a glass reaction vessel equipped with a thermometer, a stirring device, a reflux device, a nitrogen introducing tube and a dropping device, and stirred. The reaction vessel was purged with nitrogen below, and the temperature was raised to 80 ° C. in a nitrogen atmosphere. Thereafter, 2 parts of methacrylic acid, 0.2 part of acrylic acid, 17 parts of methoxypolyethylene glycol methacrylate (average number of added moles of ethylene oxide 19), 39 parts of ethylene glycol acrylate (average number of added moles of ethylene oxide 1), And the monomer aqueous solution which mixed 165 parts of water, and the liquid mixture of 3 parts of ammonium persulfate, and 47 parts of water were continuously dripped at reaction container hold | maintained at 80 degreeC in 2 hours, respectively. Furthermore, the aqueous solution of the copolymer was obtained by making it react for 1 hour in the state hold | maintained at 100 degreeC. The content of polyethylene glycol allyl ether in the copolymer was 10% by weight, and the content of water-soluble polyethylene glycol in which both terminal groups were hydrogen atoms was 0.3% by weight. This solution was adjusted to pH 4 with 30% NaOH aqueous solution. The copolymer in the liquid was a copolymer (A-10) (weight average molecular weight 14,300, Mw / Mn1.8).

<Production Example 11>
148 parts of water and 347 parts of polyethylene glycol monoallyl ether (average number of moles of ethylene oxide added: 10) were charged in a glass reaction vessel equipped with a thermometer, stirring device, refluxing device, nitrogen introducing tube and dropping device, and stirred. The reaction vessel was purged with nitrogen below, and the temperature was raised to 80 ° C. in a nitrogen atmosphere. Thereafter, a reaction solution in which 90 parts of acrylic acid, 1 part of 30% NaOH aqueous solution and 288 parts of water were mixed, and a mixed liquid of 7 parts of ammonium persulfate and 113 parts of water was maintained at 80 ° C. for 2 hours each. It was dripped continuously into the container. Furthermore, the aqueous solution of the copolymer was obtained by making it react for 1 hour in the state hold | maintained at 100 degreeC. The content of polyethylene glycol allyl ether in the copolymer was 15% by weight, and the content of water-soluble polyethylene glycol in which both terminal groups were hydrogen atoms was 0.7% by weight. This solution was adjusted to pH 7 with 30% NaOH aqueous solution. The copolymer in the liquid was a copolymer (B-1) (weight average molecular weight 16,000, Mw / Mn 1.7).

<Production Example 12>
501 parts of water and ethylene oxide adduct of 3-methyl-3-buten-1-ol (average number of moles of ethylene oxide added) in a glass reaction vessel equipped with a thermometer, a stirrer, a reflux device, a nitrogen inlet tube and a dropping device 10) 500 parts, and 2 parts of a compound in which the 3 and 3 'positions of 4,4'-dihydroxydiphenylsulfone were allyl substituted, and the reaction vessel was purged with nitrogen under stirring, and the temperature was raised to 80 ° C under a nitrogen atmosphere. Warm up. Thereafter, an aqueous monomer solution obtained by mixing 135 parts of acrylic acid and 501 parts of water and a mixed solution of 12 parts of ammonium persulfate and 188 parts of water were continuously added dropwise to a reaction vessel maintained at 80 ° C. for 1 hour. Furthermore, the aqueous solution of the copolymer was obtained by making it react for 1 hour in the state hold | maintained at 100 degreeC. The content of ethylene oxide adduct of 3-methyl-3-buten-1-ol with respect to the copolymer is 10% by weight, and the content of water-soluble polyethylene glycol in which both terminal groups are hydrogen atoms is 0. It was 6%. This solution was adjusted to pH 7 with 30% NaOH aqueous solution. The copolymer in the liquid was a copolymer (B-2) (weight average molecular weight 20,200, Mw / Mn 1.7).

<Production Example 13>
A glass reaction vessel equipped with a thermometer, a stirrer, a reflux device, a nitrogen introduction tube and a dropping device was charged with 1052 parts of water, the reaction vessel was purged with nitrogen under stirring, and the temperature was raised to 80 ° C. in a nitrogen atmosphere. Thereafter, 323 parts of methoxypolyethylene glycol methacrylate (average number of added moles of ethylene oxide: 13), 2 parts of compound in which 3 and 3 'positions of 4,4'-dihydroxydiphenylsulfone are allyl substituted, 39 parts of methacrylic acid, and water A monomer solution mixed with 357 parts and a mixed solution of 7 parts of sodium persulfate and 113 parts of water were continuously dropped into a reaction vessel maintained at 80 ° C. for 2 hours each. Furthermore, the aqueous solution of the copolymer was obtained by making it react for 1 hour in the state hold | maintained at 100 degreeC. This solution was adjusted to pH 7 with a 30% aqueous NaOH solution to obtain an aqueous solution of a salt (B-3) of a polycarboxylic acid copolymer having a weight average molecular weight of 19,000 and Mw / Mn 1.6.

<Production Example 14>
100 parts of water was charged into a glass reaction vessel equipped with a thermometer, a stirrer, a reflux device, a nitrogen introduction tube and a dropping device, the reaction vessel was purged with nitrogen under stirring, and the temperature was raised to 75 ° C. under a nitrogen atmosphere. Thereafter, an aqueous monomer solution in which 90 parts of methoxypolyethylene glycol methacrylate (average number of added moles of ethylene oxide of 18), 5 parts of methacrylic acid, 21 parts of water, and 0.3 part of 3-mercaptopropionic acid were mixed, and sodium persulfate A mixed solution of 1 part and 29 parts of water was continuously dropped into a reaction vessel maintained at 75 ° C. for 2 hours each. Furthermore, the aqueous solution of a copolymer was obtained by making it react for 1 hour in the state hold | maintained at 75 degreeC. This solution was adjusted to pH 7 with a 30% NaOH aqueous solution to obtain an aqueous solution of a salt (B-4) of a polycarboxylic acid copolymer having a weight average molecular weight of 26,000 and Mw / Mn 1.7.

<Production Example 15>
Into a glass reaction vessel equipped with a thermometer, a stirrer, a reflux device, a nitrogen introduction tube and a dripping device, 1698 parts of water was charged, the inside of the reaction vessel was replaced with nitrogen under stirring, and the temperature was raised to 80 ° C. in a nitrogen atmosphere did. Next, an aqueous monomer solution in which 1796 parts of methoxypolyethylene glycol methacrylate (average number of added moles of ethylene oxide of 25), 204 parts of methacrylic acid, 500 parts of water, and 17.6 parts of 3-mercaptopropionic acid were mixed with ammonium persulfate 18 And 168 parts of water were continuously added dropwise to a reaction vessel maintained at 80 ° C. for 4 hours. Furthermore, the aqueous solution of the copolymer was obtained by making it react for 1 hour in the state hold | maintained at 80 degreeC. This solution was adjusted to pH 7 with a 30% NaOH aqueous solution to obtain an aqueous solution of a salt (C-1) of a polycarboxylic acid copolymer having a weight average molecular weight of 28,000 and Mw / Mn 1.7.

<Production Example 16>
In a glass reaction vessel equipped with a thermometer, a stirrer, a reflux device, a nitrogen introduction tube and a dropping device, 1698 parts of water, 500 parts of polyethylene glycol monoallyl ether (average number of moles of ethylene oxide added 10), and polyethylene 2000 parts of glycol monoallyl ether (average added mole number of ethylene oxide: 30) was charged, the inside of the reaction vessel was purged with nitrogen under stirring, and the temperature was raised to 100 ° C. in a nitrogen atmosphere. Next, an aqueous monomer solution obtained by mixing 144 parts of methacrylic acid, 80 parts of acrylic acid, 500 parts of water and 5 parts of 3-mercaptopropionic acid, and a mixed solution of 18 parts of ammonium persulfate and 168 parts of water for 4 hours, 100 The solution was continuously added dropwise to a reaction vessel maintained at ° C. Furthermore, the aqueous solution of the copolymer was obtained by making it react for 1 hour in the state hold | maintained at 100 degreeC. This solution was adjusted to pH 7 with a 30% NaOH aqueous solution to obtain an aqueous solution of a salt (C-2) of a polycarboxylic acid copolymer having a weight average molecular weight of 18,000 and Mw / Mn 1.6.

<Examples 1-16 and Comparative Examples 1-8>
Coarse aggregate, fine aggregate, cement, water and the cement admixture shown in Table 2 were added as shown in Table 1 and mixed by mechanical kneading with a forced biaxial mixer for 90 seconds. Thereafter, immediately after the concrete was discharged, a fresh concrete test (slump test JISA1101 (measured as the flow value of the spread of fresh concrete), air quantity JISA1128, concrete viscosity evaluation) was performed. The viscosity of concrete was evaluated by the following criteria by sensory evaluation by five evaluators.
[Evaluation criteria for viscosity]
A: Handling is very good when the concrete is cut back with a scoop, and the separation of the concrete from the scoop is very good.
○: Good handling when the concrete is cut back with a scoop, and separation of the concrete from the scoop is good.
X: Handling when the concrete is cut back with a scoop is poor, and the concrete is not separated from the scoop.
The results are shown in Tables 2-5.

Normal Portland cement (Mitsubishi Ube, Ltd., specific gravity 3.16)
Ordinary Portland cement (manufactured by Taiheiyo Cement Co., Ltd., specific gravity 3.16)
Normal Portland cement (Made by Tokuyama Co., Ltd., specific gravity 3.16)
Tap water S1: Crushed lime sand from Tsukumi, Oita Prefecture (fine aggregate, specific gravity 2.66)
S2: Crushed stone from Shunan, Yamaguchi Prefecture (fine aggregate, specific gravity 2.66)
G1, G2: Crushed stone from Iwakuni, Yamaguchi Prefecture (coarse aggregate, specific gravity 2.73, 2.66)
Cement admixture (solid content conversion) See Table 2

  In Tables 2 to 5, “addition ratio” of the cement admixture indicates the solid content addition ratio of the admixture to the cement.

  As is clear from Tables 2 to 5, the concrete of the example showed high slump and slump flow equivalent to the comparative example. In addition, the change in the slump and the slump flow in the elapsed time of the example is small compared to the comparative example. Moreover, in the viscosity evaluation of the concrete of an Example, the favorable viscosity was shown just after concrete mixing and time passed. In particular, Example 6 using both the copolymers (A-1) and (C-1) showed an excellent slump flow as compared with Example 1 using the copolymer (A-1) alone. It was. In Example 7 where the copolymers (A-2) and (C-2) were used in combination, an excellent slump flow was shown compared to Example 2 where the copolymer (A-2) was used alone. . Example 13 using copolymer (A-6) and (C-1) in combination, Example 14 using copolymer (A-7) and (C-1) in combination, copolymer (A- In Example 15 in which 8) and (C-2) were used in combination, and in Example 16 in which copolymer (A-9) and (C-2) were used in combination, copolymer (A-1) was used. Compared to Example 1 used alone, the fluidity was excellent even after a long time. In particular, in Example 13, excellent fluidity was observed regardless of the elapsed time, which was the same at the elapsed time of 120 minutes, and it was found that the concrete viscosity was also reduced. As a result, when the cement admixture of the present invention exhibits excellent cement dispersibility and water-reducing properties, and is excellent in slump loss prevention performance, and when it is used as a cement composition, the viscosity of the cement composition is reduced. It shows that it can be reduced.

Claims (10)

Monomer (I) represented by the following general formula (1) 5 to 97% by weight, monomer (II) represented by the following general formula (2) 5 to 97% by weight, unsaturated monocarboxylic acid type Monomer (III) 1 to 50% by weight, other monomer (IV) copolymerizable with monomers (I) to (III) 0 to 50% by weight are obtained by copolymerization. The monomer (II) includes a monomer (IIa) in which n2 in the general formula (2) is 1 to 3 and a monomer (IIb) in which n2 in the general formula (2) is 6 to 100 A cement admixture having a polycarboxylic acid copolymer or a salt thereof (A).

(In the formula, R ¹ represents an allyl group, a methallyl group or a residue of 3-methyl-3-buten-1-ol. A ¹ O is the same or different and is an oxyalkylene having 2 to 18 carbon atoms. N1 represents the average number of moles added of the oxyalkylene group and represents a number of 1 to 100. R ² represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.

(In the formula, R ³ , R ⁴ and R ⁵ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. M represents a number of 0 to ^2. A ² O is the same. Or, differently, it represents an oxyalkylene group having 2 to 18 carbon atoms, n2 is the average number of added moles of the oxyalkylene group, and represents a number of 1 to 100. X is a hydrogen atom or 1 to 1 carbon atoms. Represents 30 hydrocarbon groups.) According to claim 1 the weight ratio of the monomer in the monomer (II) (IIa) and the monomer (IIb) (IIa) / ( IIb) is 1 / 99-99 / 1 Cement admixture. The cement admixture according to claim 1 or 2 , wherein the polycarboxylic acid copolymer or a salt thereof (A) has a weight average molecular weight of 5,000 to 60,000 in terms of polyethylene glycol. The cement admixture according to any one of claims 1 to 3 , wherein the polycarboxylic acid copolymer or a salt thereof (A) is a salt obtained by neutralizing the copolymer with an alkaline substance. The cement admixture according to any one of claims 1 to 4 , further comprising a (poly) alkylene glycol alkenyl ether monomer (B). The cement according to claim 5, wherein a content ratio of the (poly) alkylene glycol alkenyl ether monomer (B) is 1 to 90% by weight with respect to the polycarboxylic acid copolymer or a salt thereof (A). Admixture. The cement admixture according to any one of claims 1 to 6 , further comprising a water-soluble polyalkylene glycol (C) in which both terminal groups are hydrogen atoms. The content ratio of the water-soluble polyalkylene glycol (C) in which the both terminal groups are hydrogen atoms is 0.01 to 5% by weight with respect to the polycarboxylic acid copolymer or a salt thereof (A). The cement admixture according to 7 . Polyester obtained by copolymerizing the monomer (I), the monomer (III), and another monomer (VI) copolymerizable with the monomers (I) and (III) Carboxylic acid copolymer or a salt thereof (D), and / or the monomer (II), the monomer (III), and other copolymerizable with the monomers (II) and (III) The cement admixture according to any one of claims 1 to 8 , further comprising a polycarboxylic acid copolymer obtained by copolymerizing the monomer (VII) or a salt thereof (E). Cement compositions containing the cement admixture according to any one of claims 1-9.