JP2014024690A - Polycarboxylic acid-based copolymer for cement admixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polycarboxylic acid-based copolymer for a cement admixture which can exhibit high fluidity retention with passage of time, and to provide the cement admixture including such a polycarboxylic acid-based copolymer, and further to provide a cement composition including such a polycarboxylic acid-based copolymer and exhibiting high fluidity retention with passage of time.SOLUTION: The polycarboxylic acid-based copolymer for a cement admixture includes: a structural unit (I) derived from a predetermined unsaturated polyalkylene glycol ether-based monomer (a); a structural unit (II) derived from a predetermined unsaturated carboxylic acid-based monomer (b); and a structural unit (III) derived from an unsaturated carboxylic acid ester-based monomer (c), and the content of the structural unit (I) derived from the monomer (a) in the copolymer is 44 to 98 wt.%, the content of the structural unit (II) derived from the monomer (b) in the copolymer is 1 to 49 wt.%, and the content of the structural unit (III) derived from the monomer (c) in the copolymer is 1 to 7 wt.%.

Description

  The present invention relates to a copolymer composition for a cement admixture. In detail, it is related with the copolymer composition suitable as a cement admixture.

  Cement admixtures are widely used in cement compositions such as cement paste, mortar and concrete.

  The performance required for the cement admixture includes an improvement in fluidity immediately after kneading, an improvement in fluidity over time, and an improvement in strength and durability after curing.

  In recent years, cement admixtures composed mainly of polycarboxylic acid copolymers have been proposed as cement admixtures. A cement admixture mainly composed of a polycarboxylic acid copolymer can exhibit high water reduction performance.

  Structural units derived from unsaturated polyalkylene glycol ether monomers and structures derived from unsaturated carboxylic monomers as polycarboxylic acid copolymers that can exhibit high water reduction performance when used in cement admixtures Polycarboxylic acid-based copolymers containing units are known (see Patent Documents 1 to 11).

  However, the polycarboxylic acid copolymers for cement admixtures proposed so far have not been able to sufficiently improve flow retention over time.

Japanese Patent No. 3683176 Japanese Patent No. 4354699 Japanese Patent No. 4614944 JP 2007-119337 A International Publication No. 01/014438 Pamphlet International Publication No. 2003/040194 Pamphlet JP 2006-248889 A JP 2007-327067 A International Publication No. 2006/129883 Pamphlet JP 2001-220417 A JP 2002-121055 A

  An object of the present invention is to provide a polycarboxylic acid copolymer for a cement admixture that can exhibit high fluidity over time. Moreover, it is providing the cement admixture containing such a polycarboxylic acid-type copolymer. Furthermore, it is providing the cement composition which expresses high temporal fluidity retention containing such a polycarboxylic acid-type copolymer.

（一般式（１）中、Ｙは炭素数２〜１０のアルケニル基を表し、Ｒ^１Ｏは炭素数２〜１８のオキシアルキレン基の１種または２種以上を表し、Ｒ^２は水素原子または炭素数１〜１８のアルキル基を表し、ｍはオキシアルキレン基の平均付加モル数であって１〜５００である。）

（一般式（２）中、Ｒ^３、Ｒ^４、Ｒ^５は、同一または異なって、水素原子、メチル基、または−（ＣＨ_２）_ｎＣＯＯＭ^２基を表し、ｎは０〜２であり、Ｍ^１とＭ^２は、同一または異なって、水素原子、金属原子、アンモニウム基、または有機アミン基を表し、Ｒ^４とＲ^５は同時に−（ＣＨ_２）_ｎＣＯＯＭ^２基とはならず、Ｒ^５が−（ＣＨ_２）_ｎＣＯＯＭ^２基である場合には、Ｒ^３とＲ^４は、同一または異なって、水素原子またはメチル基である。） The polycarboxylic acid copolymer for cement admixture of the present invention is:
A polycarboxylic acid copolymer for cement admixture,
The copolymer includes an unsaturated polyalkylene glycol ether monomer (a) -derived structural unit (I) represented by general formula (1) and an unsaturated carboxylic acid represented by general formula (2). A structural unit (II) derived from a monomer (b) and a structural unit (III) derived from an unsaturated carboxylic acid ester monomer (c),
The content of the structural unit (I) derived from the monomer (a) in the copolymer is 44% by weight to 98% by weight,
The content ratio of the structural unit (II) derived from the monomer (b) in the copolymer is 1% by weight to 49% by weight,
The content ratio of the structural unit (III) derived from the monomer (c) in the copolymer is 1% by weight to 7% by weight.

(In General Formula (1), Y represents an alkenyl group having 2 to 10 carbon atoms, R ¹ O represents one or more of oxyalkylene groups having 2 to 18 carbon atoms, and R ² represents a hydrogen atom or Represents an alkyl group having 1 to 18 carbon atoms, and m is an average added mole number of an oxyalkylene group and is 1 to 500.)

(In General Formula (2), R ³ , R ⁴ , and R ⁵ are the same or different and represent a hydrogen atom, a methyl group, or — (CH ₂ ) _n COOM ² group, and n is 0 to 2, M ¹ and M ² are the same or different and each represents a hydrogen atom, a metal atom, an ammonium group, or an organic amine group, and R ⁴ and R ⁵ are not simultaneously a — (CH ₂ ) _n COOM ² group, ^{When 5} is a — (CH ₂ ) _n COOM ² group, R ³ and R ⁴ are the same or different and are a hydrogen atom or a methyl group.)

  In preferable embodiment, Y is a C4-C5 alkenyl group in the said General formula (1).

In a preferred embodiment, in the general formula (2), R ³ and R ⁴ are both hydrogen atoms, and R ⁵ is a hydrogen atom or a methyl group.

（一般式（３）中、Ｒ^６、Ｒ^７、Ｒ^８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^９は炭素数１〜１８の炭化水素基を表す。） In a preferred embodiment, the unsaturated carboxylic acid ester monomer (c) is represented by the general formula (3).

(In General Formula (3), R ⁶ , R ⁷ , and R ⁸ are the same or different and represent a hydrogen atom or a methyl group, and R ⁹ represents a hydrocarbon group having 1 to 18 carbon atoms.)

In a preferred embodiment, in the general formula (3), R ⁹ is a hydrocarbon group having 1 to 8 carbon atoms.

  In preferable embodiment, the content rate of the structural unit (III) derived from the said monomer (c) in the said copolymer is 2 weight%-7 weight%.

  The cement admixture of the present invention contains the polycarboxylic acid copolymer for cement admixture of the present invention.

  The cement composition of the present invention comprises the polycarboxylic acid copolymer for cement admixture of the present invention, cement and water.

  ADVANTAGE OF THE INVENTION According to this invention, the polycarboxylic acid-type copolymer for cement admixtures which can express high temporal fluidity retention can be provided. Moreover, the cement admixture containing such a polycarboxylic acid-type copolymer can be provided. Furthermore, it is possible to provide a cement composition that exhibits high fluidity with time, including such a polycarboxylic acid copolymer.

（一般式（１）中、Ｙは炭素数２〜１０のアルケニル基を表し、Ｒ^１Ｏは炭素数２〜１８のオキシアルキレン基の１種または２種以上を表し、Ｒ^２は水素原子または炭素数１〜１８のアルキル基を表し、ｍはオキシアルキレン基の平均付加モル数であって１〜５００である。）

（一般式（２）中、Ｒ^３、Ｒ^４、Ｒ^５は、同一または異なって、水素原子、メチル基、または−（ＣＨ_２）_ｎＣＯＯＭ^２基を表し、ｎは０〜２であり、Ｍ^１とＭ^２は、同一または異なって、水素原子、金属原子、アンモニウム基、または有機アミン基を表し、Ｒ^４とＲ^５は同時に−（ＣＨ_２）_ｎＣＯＯＭ^２基とはならず、Ｒ^５が−（ＣＨ_２）_ｎＣＯＯＭ^２基である場合には、Ｒ^３とＲ^４は、同一または異なって、水素原子またはメチル基である。） ≪Polycarboxylic acid copolymer for cement admixture≫
The polycarboxylic acid copolymer for cement admixture of the present invention comprises a structural unit (I) derived from an unsaturated polyalkylene glycol ether monomer (a) represented by the general formula (1) and a general formula ( The structural unit (II) derived from the unsaturated carboxylic acid monomer (b) represented by 2) and the structural unit (III) derived from the unsaturated carboxylic acid ester monomer (c) are included.

(In General Formula (1), Y represents an alkenyl group having 2 to 10 carbon atoms, R ¹ O represents one or more of oxyalkylene groups having 2 to 18 carbon atoms, and R ² represents a hydrogen atom or Represents an alkyl group having 1 to 18 carbon atoms, and m is an average added mole number of an oxyalkylene group and is 1 to 500.)

(In General Formula (2), R ³ , R ⁴ , and R ⁵ are the same or different and represent a hydrogen atom, a methyl group, or — (CH ₂ ) _n COOM ² group, and n is 0 to 2, M ¹ and M ² are the same or different and each represents a hydrogen atom, a metal atom, an ammonium group, or an organic amine group, and R ⁴ and R ⁵ are not simultaneously a — (CH ₂ ) _n COOM ² group, ^{When 5} is a — (CH ₂ ) _n COOM ² group, R ³ and R ⁴ are the same or different and are a hydrogen atom or a methyl group.)

  In the polycarboxylic acid copolymer for cement admixture of the present invention, the structural unit (I) derived from the unsaturated polyalkylene glycol ether monomer (a) represented by the general formula (1) is 1 Only seeds may be included, or two or more kinds may be included.

In the polycarboxylic acid copolymer for cement admixture of the present invention, the structural unit (I) derived from the unsaturated polyalkylene glycol ether monomer (a) represented by the general formula (1) is: Specifically, it is a structural unit in which the polymerizable unsaturated double bond of the alkenyl group Y in the general formula (1) is cleaved by polymerization to form a single bond. For example, when the alkenyl group Y is represented by P = Q-, the structural unit (I) derived from the unsaturated polyalkylene glycol ether monomer (a) represented by the general formula (1) is represented by the general formula ( I).

  In the general formula (1), Y represents an alkenyl group having 2 to 10 carbon atoms. Y is preferably an alkenyl group having 2 to 5 carbon atoms, and more preferably an alkenyl group having 4 to 5 carbon atoms, from the viewpoint that the effects of the present invention can be further exhibited. Examples of Y include a vinyl group, allyl group, methallyl group, 3-butenyl group, 3-methyl-3-butenyl group, 3-methyl-2-butenyl group, 2-methyl-3-butenyl group, and 2-methyl. -2-butenyl group, 1,1-dimethyl-2-propenyl group and the like. Among these, an allyl group, a methallyl group, and a 3-methyl-3-butenyl group are particularly preferable in that the effects of the present invention can be further exhibited.

In the general formula (1), R ¹ O represents one or more of oxyalkylene groups having 2 to 18 carbon atoms. R ¹ O is preferably one or more types of oxyalkylene groups having 2 to 8 carbon atoms, and more preferably one or more types of oxyalkylene groups having 2 to 4 carbon atoms. Examples of R ¹ O include an oxyethylene group, an oxypropylene group, an oxybutylene group, and an oxystyrene group. Examples of the addition format of R ¹ O include random addition, block addition, and alternate addition. In order to secure a balance between hydrophilicity and hydrophobicity, it is preferable that an oxyethylene group contains an oxyethylene group as an essential component. More specifically, with respect to 100 mol% of all oxyalkylene groups, 50 mol% or more is more preferably an oxyethylene group, 70 mol% or more is more preferably an oxyethylene group, and 90 mol% or more. Is particularly preferably an oxyethylene group.

  In the above general formula (1), m is the average number of added moles of the oxyalkylene group, and m is 1 to 500. m is preferably 2 to 300, more preferably 5 to 300, still more preferably 10 to 300, particularly preferably 15 to 300, and most preferably 20 to 300. The smaller m is, the lower the hydrophilicity of the resulting polymer and the lower the dispersion performance. If m exceeds 500, copolymerization reactivity may be reduced.

In the general formula (1), R ² represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms. Examples of the alkyl group having 1 to 18 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, cyclohexyl group, 2-ethylhexyl group, n- An octyl group, an isooctyl group, a lauryl group, a stearyl group, etc. are mentioned.

  Examples of the unsaturated polyalkylene glycol ether monomer (a) include 3-methyl-3-buten-1-ol, 3-methyl-2-buten-1-ol, 2-methyl-3-butene- An alkylene oxide is added to an unsaturated alcohol such as 2-ol, 2-methyl-2-buten-1-ol, 2-methyl-3-buten-1-ol, 2-methyl-2-propen-1-ol, etc. The compound added 500 mol is mentioned.

  Specific examples of the unsaturated polyalkylene glycol ether monomer (a) include polyethylene glycol mono (3-methyl-3-butenyl) ether and polyethylene glycol mono (3-methyl-2-butenyl) ether. Polyethylene glycol mono (2-methyl-3-butenyl) ether, polyethylene glycol mono (2-methyl-2-butenyl) ether, polyethylene glycol mono (1,1-dimethyl-2-propenyl) ether, polyethylene glycol mono (2 -Methyl-2-propenyl) ether, polyethylene polypropylene glycol mono (3-methyl-3-butenyl) ether, methoxypolyethylene glycol mono (3-methyl-3-butenyl) ether, ethoxypolyethylene glycol mono (3- Til-3-butenyl) ether, 1-propoxypolyethylene glycol mono (3-methyl-3-butenyl) ether, cyclohexyloxypolyethylene glycol mono (3-methyl-3-butenyl) ether, 1-octyloxypolyethylene glycol mono (3 -Methyl-3-butenyl) ether, nonylalkoxy polyethylene glycol mono (3-methyl 3-butenyl) ether, lauryl alkoxy polyethylene glycol mono (3-methyl-3-butenyl) ether, stearyl alkoxy polyethylene glycol mono (3-methyl- 3-butenyl) ether, phenoxy polyethylene glycol mono (3-methyl-3-butenyl) ether, naphthoxy polyethylene glycol mono (3-methyl-3-butenyl) ether Methoxy polyethylene glycol mono (2-methyl-2-propenyl) ether, ethoxy polyethylene glycol mono (2-methyl-2-propenyl) ether, 1-propoxy polyethylene glycol mono (2-methyl-2-propenyl) ether, cyclohexyloxypolyethylene Glycol mono (2-methyl-2-propenyl) ether, 1-octyloxypolyethylene glycol mono (2-methyl-2-propenyl) ether, nonylalkoxy polyethylene glycol mono (2-methyl-2-propenyl) ether, laurylalkoxypolyethylene Glycol mono (2-methyl-2-propenyl) ether, stearylalkoxypolyethylene glycol mono (2-methyl-2-propenyl) ether, phenoxypolyether Examples include tylene glycol mono (2-methyl-2-propenyl) ether and naphthoxypolyethylene glycol mono (2-methyl-2-propenyl) ether.

  The polycarboxylic acid copolymer for cement admixture of the present invention has only one type of structural unit (II) derived from the unsaturated carboxylic acid monomer (b) represented by the general formula (2). It may be included, or two or more types may be included.

The structural unit (II) derived from the unsaturated carboxylic acid monomer (b) represented by the general formula (2) in the polycarboxylic acid copolymer for cement admixture of the present invention is specifically Is represented by the general formula (II).

In the general formula ^{(2), R 3, R} 4, R 5 are the same or different, a hydrogen atom, a methyl group, or _- represents a _(CH ²⁾ n COOM 2 group. n is 0-2. R ⁴ and R ⁵ are not simultaneously a — (CH ₂ ) _n COOM ² group. When R ⁵ is a — (CH ₂ ) _n COOM ² group, R ³ and R ⁴ are the same or different and are a hydrogen atom or a methyl group.

In the general formula (2), R ³ and R ⁴ are each preferably a hydrogen atom, and R ⁵ is preferably a hydrogen atom or a methyl group, from the viewpoint that the effects of the present invention can be further exhibited.

In General Formula (2), M ¹ and M ² are the same or different and each represents a hydrogen atom, a metal atom, an ammonium group, or an organic amine group.

  Any appropriate metal atom can be adopted as the metal atom. Examples of such metal atoms include monovalent metal atoms such as lithium, sodium and potassium; divalent metal atoms such as alkaline earth metal atoms such as calcium and magnesium; and the like.

  As the organic amine group, any appropriate organic amine group can be adopted as long as it is a protonated organic amine. Examples of the organic amine group include alkanolamine groups such as ethanolamine group, diethanolamine group and triethanolamine group, and triethylamine group.

  Examples of the unsaturated carboxylic acid monomer (b) include an unsaturated monocarboxylic acid monomer (b-1) and an unsaturated dicarboxylic acid monomer (b-2). The unsaturated carboxylic acid monomer (b) is preferably an unsaturated monocarboxylic acid monomer (b-1) from the viewpoint that the effects of the present invention can be further exhibited.

  Any appropriate unsaturated monocarboxylic acid monomer can be adopted as the unsaturated monocarboxylic acid monomer (b-1). The unsaturated monocarboxylic acid monomer (b-1) is preferably a (meth) acrylic acid monomer. Specific examples include acrylic acid, methacrylic acid, crotonic acid, and monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts thereof. From the viewpoint of copolymerization, the unsaturated monocarboxylic acid monomer (b-1) is more preferably (meth) acrylic acid and / or a salt thereof (monovalent metal salt, divalent metal salt, Ammonium salts, organic amine salts, and the like, and more preferably acrylic acid and / or salts thereof (monovalent metal salts, divalent metal salts, ammonium salts, organic amine salts, etc.).

  Any appropriate unsaturated dicarboxylic acid monomer can be adopted as the unsaturated dicarboxylic acid monomer (b-2). Specific examples of the unsaturated dicarboxylic acid monomer (b-2) include maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, and monovalent metal salts and divalent metals thereof. Examples thereof include salts, ammonium salts, and organic amine salts. As the unsaturated dicarboxylic acid monomer (b-2), maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, and salts thereof (monovalent metal salt, divalent metal salt, Ammonium salts, organic amine salts, etc., more preferably maleic acid, maleic anhydride, fumaric acid, citraconic acid, and salts thereof (monovalent metal salts, divalent metal salts, ammonium salts, organic amine salts) Α, β-unsaturated dicarboxylic acid-based monomer.

  The polycarboxylic acid copolymer for cement admixture of the present invention may contain only one type of structural unit (III) derived from the unsaturated carboxylic acid ester monomer (c), Two or more kinds may be contained.

（一般式（３）中、Ｒ^６、Ｒ^７、Ｒ^８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^９は炭素数１〜１８の炭化水素基を表す。） Any appropriate unsaturated carboxylic acid ester monomer can be adopted as the unsaturated carboxylic acid ester monomer (c) as long as the effects of the present invention are not impaired. Such an unsaturated carboxylic acid ester monomer (c) is preferably an unsaturated carboxylic acid ester monomer represented by the general formula (3).

(In General Formula (3), R ⁶ , R ⁷ , and R ⁸ are the same or different and represent a hydrogen atom or a methyl group, and R ⁹ represents a hydrocarbon group having 1 to 18 carbon atoms.)

The structural unit (III) derived from the unsaturated carboxylic acid monomer (c) represented by the general formula (3) in the polycarboxylic acid copolymer for cement admixture of the present invention is specifically Is represented by the general formula (III).

In General Formula (3), R ⁶ , R ⁷ and R ⁸ are the same or different and represent a hydrogen atom or a methyl group, and R ⁹ represents a hydrocarbon group having 1 to 18 carbon atoms. Examples of the hydrocarbon group having 1 to 18 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, cyclohexyl group, 2-ethylhexyl group, n -An octyl group, an isooctyl group, a lauryl group, a stearyl group etc. are mentioned.

In the general formula (3), R ⁹ is preferably a hydrocarbon group having 1 to 8 carbon atoms from the viewpoint that the effects of the present invention can be further exhibited. Specifically, as R ⁹ , methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, cyclohexyl group, 2-ethylhexyl group, n-octyl group, An isooctyl group is preferred. Also, in that it can further exhibit the effect of the present invention, in the general formula (3), R ⁶ and R ⁷ are preferably both hydrogen atoms.

  The total content of the structural unit (I), the structural unit (II) and the structural unit (III) in the polycarboxylic acid copolymer for cement admixture of the present invention is preferably 46% by weight. To 100% by weight, more preferably 50% to 100% by weight, still more preferably 70% to 100% by weight, particularly preferably 90% to 100% by weight, most preferably 95%. % By weight to 100% by weight. If the total content of the structural unit (I), the structural unit (II) and the structural unit (III) in the polycarboxylic acid copolymer for cement admixture of the present invention is within the above range, It is possible to provide a polycarboxylic acid copolymer for cement admixture that can provide a high-performance cement admixture having high fluidity retention over time.

  The total content of the structural unit (I), the structural unit (II), and the structural unit (III) in the polycarboxylic acid copolymer for cement admixture of the present invention is, for example, the cement admixture. It can be known by various structural analyzes (for example, NMR, etc.) of the polycarboxylic acid copolymer for the agent. In addition, the various calculations calculated based on the amounts of various monomers used when producing the polycarboxylic acid copolymer for cement admixture of the present invention without performing the various structural analyzes as described above. In the polycarboxylic acid copolymer for cement admixture of the present invention, the structural unit (I), the structural unit (II), and the structural unit (III) It is good also as a total content rate.

  The content ratio of the structural unit (I) in the polycarboxylic acid copolymer for cement admixture of the present invention is 44% to 98% by weight, preferably 50% to 97% by weight, and more preferably. Is 60% to 96% by weight, more preferably 70% to 95% by weight, particularly preferably 80% to 94% by weight, and most preferably 85% to 93% by weight. If the content ratio of the structural unit (I) in the polycarboxylic acid copolymer for cement admixture of the present invention is within the above range, a high-performance cement admixture having high fluidity over time can be provided. A polycarboxylic acid copolymer for cement admixture can be provided.

  The content ratio of the structural unit (I) in the polycarboxylic acid copolymer for cement admixture of the present invention is, for example, various structural analyzes of the polycarboxylic acid copolymer for cement admixture (for example, NMR, etc. ) In addition, the use of the unsaturated polyalkylene glycol ether monomer (a) used when producing the polycarboxylic acid copolymer for cement admixture of the present invention without performing various structural analyzes as described above. The content of the structural unit (I) in the polycarboxylic acid copolymer for cement admixture of the present invention having the content ratio of the structural unit (I) derived from the monomer (a) calculated based on the amount It is good as a ratio.

  The content ratio of the structural unit (II) in the polycarboxylic acid copolymer for cement admixture of the present invention is 1% by weight to 49% by weight, preferably 1.5% by weight to 40% by weight, More preferably, it is 2 to 30% by weight, more preferably 2.5 to 20% by weight, particularly preferably 3 to 15% by weight, and most preferably 3.5 to 10% by weight. When the content ratio of the structural unit (II) in the polycarboxylic acid copolymer for cement admixture of the present invention is within the above range, a high-performance cement admixture having high fluidity with time can be provided. A polycarboxylic acid copolymer for cement admixture can be provided.

  The content ratio of the structural unit (II) in the polycarboxylic acid copolymer for cement admixture of the present invention is, for example, various structural analyzes of the polycarboxylic acid copolymer for cement admixture (for example, NMR, etc. ) Further, the amount of the unsaturated carboxylic acid monomer (b) used in producing the polycarboxylic acid copolymer for cement admixture of the present invention can be used without performing various structural analyzes as described above. The content ratio of the structural unit (II) derived from the monomer (b) calculated based on the content ratio of the structural unit (II) in the polycarboxylic acid copolymer for cement admixture of the present invention Also good.

  The content ratio of the structural unit (III) in the polycarboxylic acid copolymer for cement admixture of the present invention is 1 wt% to 7 wt%, preferably 1.5 wt% to 7 wt%, More preferably, it is 2 to 7% by weight. If the content ratio of the structural unit (III) in the polycarboxylic acid copolymer for cement admixture of the present invention is within the above range, a high-performance cement admixture having high fluidity over time can be provided. A polycarboxylic acid copolymer for cement admixture can be provided. In the polycarboxylic acid-based copolymer for cement admixture of the present invention, the effect of the present invention of high fluidity retention over time can be achieved by adjusting the content ratio of the structural unit (III) within the above range. Can be significantly expressed.

  The content ratio of the structural unit (III) in the polycarboxylic acid copolymer for cement admixture of the present invention is, for example, various structural analyzes of the polycarboxylic acid copolymer for cement admixture (for example, NMR, etc. ) Further, the amount of the unsaturated carboxylic acid ester monomer (c) used when producing the polycarboxylic acid copolymer for cement admixture of the present invention without performing various structural analyzes as described above. The content ratio of the structural unit (III) in the polycarboxylic acid copolymer for cement admixture of the present invention having the content ratio of the structural unit (III) derived from the monomer (c) calculated based on It is also good.

  In the polycarboxylic acid copolymer for cement admixture of the present invention, in addition to the structural unit (I), the structural unit (II), and the structural unit (III), any appropriate and other single amount The structural unit (IV) derived from the body (d) may be included. The content ratio of the structural unit (IV) in the polycarboxylic acid copolymer for cement admixture of the present invention can be appropriately set according to the purpose within a range not impairing the effects of the present invention. The content ratio of the structural unit (IV) in the polycarboxylic acid copolymer for cement admixture of the present invention is, for example, preferably 0% by weight to 54% by weight.

  The content ratio of the structural unit (IV) in the polycarboxylic acid copolymer for cement admixture of the present invention is, for example, various structural analyzes of the polycarboxylic acid copolymer for cement admixture (for example, NMR, etc. ) Moreover, it is calculated based on the use amount of the other monomer (d) used when producing the polycarboxylic acid-based copolymer for cement admixture of the present invention without performing various structural analyzes as described above. The content ratio of the structural unit (IV) derived from the monomer (d) may be the content ratio of the structural unit (IV) in the polycarboxylic acid copolymer for cement admixture of the present invention.

  The polycarboxylic acid copolymer for cement admixture of the present invention may contain only one type of structural unit (IV) derived from other monomer (d), or two or more types. May be.

  Specific examples of the other monomer (d) include half esters and diesters of the unsaturated dicarboxylic acid monomer (b-2) and an alcohol having 1 to 30 carbon atoms; Half amide and diamide of unsaturated dicarboxylic acid monomer (b-2) and amine having 1 to 30 carbon atoms; alkyl (poly) alkylene glycol and unsaturated dicarboxylic acid monomer (b-2) ) And half esters and diesters; a half of the unsaturated dicarboxylic acid monomer (b-2) and a glycol having 2 to 18 carbon atoms or a polyalkylene glycol having 2 to 500 addition moles of these glycols Esters, diesters; alkoxy (poly) alkylene glycos in which 1 to 500 moles of an alkylene oxide having 2 to 18 carbon atoms is added to an alcohol having 1 to 30 carbon atoms And esters of unsaturated monocarboxylic acid monomers (b-1) such as (meth) acrylic acid; (poly) ethylene glycol monomethacrylate, (poly) propylene glycol monomethacrylate, (poly) butylene glycol monomethacrylate 1-500 mol adducts of alkylene oxide having 2 to 18 carbon atoms to unsaturated monocarboxylic acid monomer (b-1) such as (meth) acrylic acid, etc .; maleamic acid and the number of carbon atoms Half amides of 2-18 glycols or polyalkylene glycols having an addition mole number of these glycols of 2 to 500; triethylene glycol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, polypropylene glycol di ( (Meth) acrylate, (poly) ethylene glycol (poly) (Poly) alkylene glycol di (meth) acrylates such as propylene glycol di (meth) acrylate; bifunctional such as hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane di (meth) acrylate (Meth) acrylates; (poly) alkylene glycol dimaleates such as triethylene glycol dimaleate and polyethylene glycol dimaleate; vinyl sulfonate, (meth) allyl sulfonate, 2- (meth) acryloxyethyl sulfonate, 3- (meta ) Acryloxypropyl sulfonate, 3- (meth) acryloxy-2-hydroxypropyl sulfonate, 3- (meth) acryloxy-2-hydroxypropyl sulfophenyl ether, 3- (meth) acrylate Liloxy-2-hydroxypropyloxysulfobenzoate, 4- (meth) acryloxybutylsulfonate, (meth) acrylamide methylsulfonic acid, (meth) acrylamide ethylsulfonic acid, 2-methylpropanesulfonic acid (meth) acrylamide, styrenesulfonic acid Unsaturated carboxylic acids such as, monovalent metal salts, divalent metal salts, ammonium salts, organic amine salts thereof; and unsaturated monocarboxylic acid monomers (b-1) such as methyl (meth) acrylamide Amides with amines having 1 to 30 carbon atoms; vinyl aromatics such as styrene, α-methylstyrene, vinyltoluene, p-methylstyrene; 1,4-butanediol mono (meth) acrylate, 1,5- Pentanediol mono (meth) acrylate, 1,6-hexanediol Alkanediol mono (meth) acrylates such as (meth) acrylate; dienes such as butadiene, isoprene, 2-methyl-1,3-butadiene, 2-chloro-1,3-butadiene; (meth) acrylamide, (meta ) Unsaturated amides such as acrylic alkylamide, N-methylol (meth) acrylamide, N, N-dimethyl (meth) acrylamide; Unsaturated cyanides such as (meth) acrylonitrile, α-chloroacrylonitrile; Vinyl acetate, propionic acid Unsaturated esters such as vinyl; aminoethyl (meth) acrylate, methylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, dibutylamino (meth) acrylate Unsaturated amines such as ethyl and vinylpyridine Divinyl aromatics such as divinylbenzene; cyanurates such as triallyl cyanurate; allyls such as (meth) allyl alcohol and glycidyl (meth) allyl ether; unsaturated amino compounds such as dimethylaminoethyl (meth) acrylate; ; 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; polydimethylsiloxanepropylaminomaleamic acid, polydimethyl Siloxane aminopropylene aminomaleamic acid, polydimethylsiloxane-bis- (propylaminomaleamic acid), polydimethylsiloxa -Bis- (dipropylaminomaleamic acid), polydimethylsiloxane- (1-propyl-3-acrylate), polydimethylsiloxane- (1-propyl-3-methacrylate), polydimethylsiloxane-bis- (1-propyl) -3-acrylate), siloxane derivatives such as polydimethylsiloxane-bis- (1-propyl-3-methacrylate); and the like.

  The weight average molecular weight (Mw) in terms of polyethylene glycol by gel permeation chromatography (GPC) is preferably 10,000 to 300,000, more preferably 10,000 to the polycarboxylic acid copolymer for cement admixture of the present invention. 100000, more preferably 10,000 to 80,000. When the weight average molecular weight (Mw) is in the above range, it is possible to provide a polycarboxylic acid copolymer for cement admixture that can provide a high-performance cement admixture having high fluidity with time.

  The polycarboxylic acid copolymer for cement admixture of the present invention can be produced by any suitable method. The polycarboxylic acid copolymer for cement admixture of the present invention is preferably a monomer component containing the monomer (a), the monomer (b) and the monomer (c). The polymerization can be carried out by carrying out in the presence of a polymerization initiator. The polycarboxylic acid copolymer for cement admixture of the present invention uses, for example, an unsaturated alcohol before addition of alkylene oxide, instead of the monomer (a), and the above monomer. (B) and the monomer (c) (and, if necessary, the other monomer (d)) are polymerized in the presence of a polymerization initiator and then an alkylene oxide is added. Can be manufactured.

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

  When the monomer component is polymerized, as a polymerization initiator, a water-soluble polymerization initiator, for example, persulfate such as ammonium persulfate, sodium persulfate, potassium persulfate; hydrogen peroxide; benzoyl peroxide, Peroxides such as lauroyl peroxide, sodium peroxide, t-butyl hydroperoxide, cumene hydroperoxide; azoamidine compounds such as 2,2′-azobis-2-methylpropionamidine hydrochloride; 2,2′-azobis- A cyclic azoamidine compound such as 2- (2-imidazolin-2-yl) propane hydrochloride; an azonitrile compound such as 2-carbamoylazoisobutyronitrile; an azo compound such as azobisisobutyronitrile; In producing the polycarboxylic acid copolymer for cement admixture of the present invention, it is particularly preferable to use a peroxide as the polymerization initiator. Examples of such peroxides include persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate; hydrogen peroxide; benzoyl peroxide, lauroyl peroxide, sodium peroxide, t-butyl hydroperoxide, And peroxides such as cumene hydroperoxide;

In producing the polycarboxylic acid copolymer for cement admixture of the present invention, it is preferable to use the peroxide and a reducing agent in combination as a polymerization initiator. Any appropriate reducing agent can be adopted as such a reducing agent. For example, salts of metals in a low valence state such as iron (II), tin (II), titanium (III), chromium (II), V (II), Cu (II), etc. Amine compounds such as monoethanolamine, diethanolamine, triethanolamine, hydroxylamine, hydroxylamine hydrochloride, hydrazine and their salts; sodium dithionite, sodium formaldehyde sulfoxylate, sodium hydroxymethanesulfinate dihydrate; Organic compounds containing —SH group, —SO ₂ H group, —NHNH ₂ group, —COCH (OH) — group and salts thereof; alkali metal sulfites such as sodium sulfite, sodium bisulfite, metabisulfite; Phosphoric acid, sodium hypophosphite, sodium hydrosulfite, sodium hyponitrite Lower oxides such as D-fructose, D-glucose, etc .; thiourea compounds such as thiourea and thiourea dioxide; L-ascorbic acid (salt), L-ascorbic acid ester, erythorbic acid (salt), Erythorbic acid ester; and the like.

  The combination of the peroxide and the reducing agent is preferably a combination of a water-soluble peroxide and a reducing agent, such as a combination of hydrogen peroxide and L-ascorbic acid, hydrogen peroxide and erythorbic acid, and the like. A combination of hydrogen peroxide and a mole salt, a combination of sodium persulfate and sodium bisulfite, and a combination of ammonium persulfate and L-ascorbic acid. A particularly preferable combination is a combination of ammonium persulfate and L-ascorbic acid in that the effects of the present invention can be expressed more effectively.

  The amount of the peroxide used is preferably 0.01 mol% to 30 mol%, more preferably 0.1 mol% to 20 mol%, based on the total amount of the monomer components, Preferably they are 0.5 mol%-10 mol%. There exists a possibility that an unreacted monomer may increase that the usage-amount of the said peroxide is less than 0.01 mol% with respect to the total amount of a monomer component. When the amount of the peroxide used exceeds 30 mol% with respect to the total amount of the monomer components, a polycarboxylic acid copolymer having a large number of oligomer parts may be obtained.

  The amount of the reducing agent to be used is preferably 0.1 mol% to 500 mol%, more preferably 1 mol% to 200 mol%, still more preferably 10 mol% to 100 mol%. When the amount of the reducing agent used is less than 0.1 mol% with respect to the peroxide, active radicals are not sufficiently generated, and the amount of unreacted monomers may increase. When the amount of the reducing agent used exceeds 500 mol% with respect to the peroxide, there is a risk that the reducing agent remaining without reacting with hydrogen peroxide will increase.

  In the polymerization of the monomer component, it is preferable that at least one of the peroxide and the reducing agent is always present in the reaction system. Specifically, it is preferable that the peroxide and the reducing agent are not added simultaneously. If peroxide and reducing agent are simultaneously added at once, the peroxide and reducing agent react rapidly, generating a large amount of reaction heat immediately after the addition, making reaction control difficult, and then radical concentration Therefore, a large amount of unreacted monomer components may remain. Furthermore, the radical concentration with respect to the monomer component is extremely different between the initial and second half of the reaction, so the molecular weight distribution becomes extremely large, and the performance when the resulting copolymer is used as a cement admixture may be reduced. There is. Therefore, for example, it is preferable to employ a method in which both the peroxide and the reducing agent are added over a long period of time, such as a method of continuously adding them by dropping or the like, or a method of adding them separately. The time from when one of the peroxide and the reducing agent is charged to when the other is started is preferably within 5 hours, more preferably within 3 hours.

  Any appropriate reaction temperature may be employed as the reaction temperature for the polymerization of the monomer components as long as the effects of the present invention are not impaired. Such a reaction temperature is preferably 30 ° C to 90 ° C, more preferably 35 ° C to 85 ° C, and further preferably 40 ° C to 80 ° C. If the polymerization reaction temperature is out of the above range, the polymerization rate may be lowered or the productivity may be lowered.

  Any appropriate polymerization time can be adopted as the polymerization time for the polymerization of the monomer component as long as the effects of the present invention are not impaired. The polymerization time is preferably 0.5 hours to 10 hours, more preferably 0.5 hours to 8 hours, and further preferably 1 hour to 6 hours. If the polymerization time is out of the above range, the polymerization rate may be lowered or the productivity may be lowered.

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

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

  Any appropriate chain transfer agent can be adopted as the chain transfer agent. Specific examples of such chain transfer agents include mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, octyl thioglycolate, and 3-mercaptopropion. Thiol chain transfer agents such as octyl acid, 2-mercaptoethanesulfonic acid, n-dodecyl mercaptan, octyl mercaptan, butylthioglycolate; halides such as carbon tetrachloride, methylene chloride, bromoform, bromotrichloroethane; Secondary alcohol; phosphorous acid, hypophosphorous acid, and salts thereof (sodium hypophosphite, potassium hypophosphite, etc.), sulfurous acid, hydrogen sulfite, dithionic acid, metabisulfite, and salts thereof ( Sodium sulfite, potassium sulfite, Sodium hydrogen sulfate, potassium hydrogen sulfite, sodium dithionite, potassium dithionite, sodium metabisulfite, meta lower oxides of potassium metabisulfite and the like) and salts thereof; and the like.

  In order to obtain a copolymer having a predetermined molecular weight with good reproducibility, it is important to allow the copolymerization reaction to proceed stably. For this reason, when performing solution polymerization, the dissolved oxygen concentration of the solvent used at 25 ° C. is preferably 5 ppm or less, more preferably 0.01 ppm to 4 ppm, and further preferably 0.01 ppm to 2 ppm. Yes, particularly preferably from 0.01 ppm to 1 ppm.

The dissolved oxygen concentration of the solvent may be adjusted in the reaction vessel, or a solvent whose dissolved oxygen amount is adjusted in advance may be used. Examples of the method for driving off oxygen in the solvent include the following methods (1) to (5).
(1) After an inert gas such as nitrogen is pressure-filled in a sealed container containing a solvent, the partial pressure of oxygen in the solvent is lowered by lowering the pressure in the sealed container. You may reduce the pressure in an airtight container under nitrogen stream.
(2) The liquid phase portion is vigorously stirred for a long time while the gas phase portion in the container containing the solvent is replaced with an inert gas such as nitrogen.
(3) An inert gas such as nitrogen is bubbled in the solvent in the container for a long time.
(4) The solvent is once boiled and then cooled in an inert gas atmosphere such as nitrogen.
(5) A static mixer (static mixer) is installed in the middle of the pipe, and an inert gas such as nitrogen is mixed in the pipe for transferring the solvent to the polymerization reaction tank.

  The copolymer obtained by the production method as described above can be used as it is as the polycarboxylic acid copolymer for cement admixture of the present invention, but from the viewpoint of handleability, It is preferable to adjust the pH to 5 or more. In this case, the polymerization may be carried out at a pH of 5 or more, but in this case, the polymerization rate may decrease and at the same time the copolymerizability may deteriorate, so the polymerization is carried out at a pH of less than 5 and the pH is raised to 5 or more after the polymerization. It is preferable to adjust. The pH can be adjusted using, for example, an alkaline substance such as inorganic salt such as hydroxide or carbonate of monovalent metal or divalent metal; ammonia; organic amine;

  The concentration of the polycarboxylic acid copolymer for cement admixture of the present invention can be adjusted as necessary to the solution obtained by the production.

  The polycarboxylic acid copolymer for cement admixture of the present invention may be used as it is in the form of a solution, or it may be neutralized with a divalent metal hydroxide such as calcium or magnesium to obtain a polyvalent metal. It may be used after it is made into a salt and dried, or supported on an inorganic powder such as silica fine powder and dried.

≪Cement admixture≫
The polycarboxylic acid-based copolymer for cement admixture of the present invention can be used as a cement admixture in combination with any appropriate component as required.

  Examples of the component that can be used as a cement admixture together with the polycarboxylic acid copolymer for cement admixture of the present invention include a cement dispersant. When the cement dispersant is used, the blending ratio of the polycarboxylic acid copolymer for cement admixture of the present invention and the cement dispersant (polycarboxylic acid copolymer for cement admixture of the present invention / cement dispersant) is Although it is not uniquely determined depending on the type of cement dispersant used, blending conditions, test conditions, etc., it is preferably 1-99 / 99-1 as a weight ratio (% by weight) in terms of solid content. More preferably, it is 5-95 / 95-5, More preferably, it is 10-90 / 90-10. Only one cement dispersant may be used, or two or more cement dispersants may be used.

  Examples of the cement dispersant include a sulfonic acid-based dispersant having a sulfonic acid group in the molecule, and a polycarboxylic acid-based dispersant having a polyoxyalkylene chain and a carboxyl group in the molecule.

  Examples of the sulfonic acid-based dispersant include polyalkylaryl sulfonate-based sulfonic acid-based dispersants such as naphthalene sulfonic acid formaldehyde condensate, methyl naphthalene sulfonic acid formaldehyde condensate and anthracene sulfonic acid formaldehyde condensate; melamine sulfonic acid Melamine formalin sulfonate-based sulfonic acid dispersants such as formaldehyde condensates; Aromatic amino sulfonate-based sulfonic acid dispersants such as aminoaryl sulfonic acid-phenol-formaldehyde condensates; lignin sulfonates, Examples thereof include lignin sulfonate sulfonic acid dispersants such as modified lignin sulfonate; polystyrene sulfonate sulfonic acid dispersants;

  Examples of the polycarboxylic acid-based dispersant include a polyalkylene glycol mono (meth) acrylate monomer having a polyoxyalkylene chain in which an alkylene oxide having 2 to 18 carbon atoms is added in an average addition mole number of 2 to 300. And a copolymer obtained by copolymerizing monomer components containing a (meth) acrylic acid monomer as essential components; an alkylene oxide having 2 to 3 carbon atoms was added in an average addition mole number of 2 to 300 Contains three types of monomers, polyalkylene glycol mono (meth) acrylic acid ester monomer having a polyoxyalkylene chain, (meth) acrylic acid monomer, and (meth) acrylic acid alkyl ester as essential components A copolymer obtained by copolymerizing monomer components; a polyoxy-containing alkylene oxide having 2 to 3 carbon atoms added in an average addition mole number of 2 to 300 Polyalkylene glycol mono (meth) acrylic acid ester monomer having an alkylene chain, (meth) acrylic acid monomer and (meth) allylsulfonic acid (salt) (or vinylsulfonic acid (salt) or p- ( A copolymer obtained by copolymerizing a monomer component containing three types of monomers of any one of (meth) allyloxybenzenesulfonic acid (salt)] as an essential component; 50 types of three monomers: a polyalkylene glycol mono (meth) acrylic acid ester monomer, a (meth) acrylic acid monomer, and a (meth) allylsulfonic acid (salt) having an added polyoxyalkylene chain (Meth) acrylamide and / or 2- (meth) acrylamide-2 are further added to the copolymer obtained by copolymerizing the monomer component containing as an essential component. A copolymer obtained by graft polymerization of methylpropanesulfonic acid; an average addition mole number of a polyethylene glycol mono (meth) acrylate monomer having a polyoxyalkylene chain in which ethylene oxide is added in an average addition mole number of 5 to 50 and ethylene oxide. 1 to 30 added polyethylene glycol mono (meth) allyl ether monomer, (meth) acrylic acid monomer and (meth) allylsulfonic acid (salt) (or p- (meta) ) Copolymer obtained by copolymerizing monomer components containing 4 types of monomers of any one of allyloxybenzenesulfonic acid (salt) as essential components; average of alkylene oxide having 2 to 18 carbon atoms Polyalkylene glycol mono- (medium having a polyoxyalkylene chain added in 2 to 300 addition moles. A) a copolymer obtained by copolymerizing a monomer component containing an allyl ether monomer and a maleic acid monomer as essential components; an alkylene oxide having 2 to 4 carbon atoms in terms of an average addition mole number Copolymerizing a monomer component containing 2 to 300 added polyoxyalkylene chain-containing polyalkylene glycol mono (meth) allyl ether monomer and maleic acid polyalkylene glycol ester monomer as essential components Copolymer obtained; a polyalkylene glycol 3-methyl-3-butenyl ether monomer having a polyoxyalkylene chain in which an alkylene oxide having 2 to 4 carbon atoms is added in an average addition mole number of 2 to 300, and malein And a copolymer obtained by copolymerizing a monomer component containing an acid monomer as an essential component.

  The cement admixture of the present invention can contain any appropriate other cement additive (material) as long as the effects of the present invention are not impaired. Examples of such other cement additives (materials) include other cement additives (materials) exemplified in the following (1) to (20). The blending ratio of the polycarboxylic acid copolymer for cement admixture of the present invention and such other cement additives (materials) is arbitrary depending on the type and purpose of the other cement additives (materials) used. An appropriate blending ratio can be adopted.

(1) Water-soluble polymer substance Examples of the water-soluble polymer substance include polyacrylic acid (sodium), polymethacrylic acid (sodium), polymaleic acid (sodium), and sodium salt of acrylic acid / maleic acid copolymer. Nonionic cellulose ethers such as methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, hydroxypropyl cellulose; methyl cellulose, ethyl cellulose, hydroxyethyl The hydrogen atoms of some or all of the alkylated or hydroxyalkylated derivatives of polysaccharides such as cellulose and hydroxypropylcellulose have a hydrocarbon chain having 8 to 40 carbon atoms as a partial structure. A polysaccharide derivative substituted with a hydrophobic substituent and an ionic hydrophilic substituent containing a sulfonic acid group or a salt thereof as a partial structure; yeast glucan, xanthan gum, β-1.3 glucans (linear, Any of the branched chains may be used. For example, polysaccharides produced by microbial fermentation such as curdlan, paramylon, pachyman, scleroglucan, laminaran); polyacrylamide; polyvinyl alcohol; starch; starch phosphate Sodium alginate; gelatin; copolymers of acrylic acid having amino groups in the molecule and quaternary compounds thereof; and the like.

(2) Polymer Emulsion Examples of the polymer emulsion include copolymers of various vinyl monomers such as alkyl (meth) acrylate.

(3) Retardant Examples of the retarder include, for example, gluconic acid, glucoheptonic acid, arabonic acid, malic acid, or citric acid, and inorganic salts thereof such as sodium, potassium, calcium, magnesium, ammonium, triethanolamine, etc. Or oxycarboxylic acids such as organic salts; monosaccharides such as glucose, fructose, galactose, saccharose, xylose, apiose, ribose, isomerized sugar, oligosaccharides such as disaccharide and trisaccharide, or oligosaccharides such as dextrin, or Polysaccharides such as dextran, sugars such as molasses containing them; sugar alcohols such as sorbitol; magnesium silicate fluoride; phosphoric acid and salts thereof or boric acid esters; aminocarboxylic acids and salts thereof; alkali-soluble proteins; Acid; Tannic acid; Phenol; Glycerin etc. Polyhydric alcohols; aminotri (methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid), and alkali metal salts and alkaline earth metal salts thereof And the like; and the like.

(4) Early strengthening agents / accelerators As early strengthening agents / accelerators, for example, soluble calcium salts such as calcium chloride, calcium nitrite, calcium nitrate, calcium bromide, calcium iodide; iron chloride, magnesium chloride, etc. Examples include chloride; sulfate; potassium hydroxide; sodium hydroxide; carbonate; thiosulfate; formate such as formic acid and calcium formate; alkanolamine; alumina cement; calcium aluminate silicate.

(5) Mineral oil-based antifoaming agent Examples of the mineral oil-based antifoaming agent include cocoon oil and liquid paraffin.

(6) Oil-based antifoaming agent Examples of the oil-based antifoaming agent include animal and vegetable oils, sesame oil, castor oil, and alkylene oxide adducts thereof.

(7) Fatty acid-based antifoaming agent Examples of the fatty acid-based antifoaming agent include oleic acid, stearic acid, and alkylene oxide adducts thereof.

(8) Fatty acid ester antifoaming agent Examples of the fatty acid ester antifoaming agent include glycerin monoricinoleate, alkenyl succinic acid derivative, sorbitol monolaurate, sorbitol trioleate, and natural wax.

(9) Oxyalkylene antifoaming agent Examples of the oxyalkylene antifoaming agent include polyoxyalkylenes such as (poly) oxyethylene (poly) oxypropylene adducts; diethylene glycol heptyl ether, polyoxyethylene oleyl ether, poly (Poly) oxyalkyl ethers such as oxypropylene butyl ether, polyoxyethylene polyoxypropylene 2-ethylhexyl ether, oxyethylene oxypropylene adducts to higher alcohols having 12 to 14 carbon atoms; polyoxypropylene phenyl ether, polyoxy (Poly) oxyalkylene (alkyl) aryl ethers such as ethylene nonylphenyl ether; 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 2,5-dimethyl-3-hex Acetylene ethers obtained by addition polymerization of alkylene oxide to acetylene alcohol such as syn-2,5-diol, 3-methyl-1-butyn-3-ol; diethylene glycol oleate, diethylene glycol laurate, ethylene glycol distearate (Poly) oxyalkylene fatty acid esters such as polyoxyethylene sorbitan monolaurate, (poly) oxyalkylene sorbitan fatty acid esters such as polyoxyethylene sorbitan trioleate; polyoxypropylene methyl ether sodium sulfate, polyoxyethylene (Poly) oxyalkylene alkyl (aryl) ether sulfate esters such as sodium dodecylphenol ether sulfate; (poly) oxyethylene Stearylphosphate esters of (poly) oxyalkylene alkyl phosphoric acid esters; polyoxyethylene such as polyoxyethylene lauryl amine (poly) oxyalkylene alkyl amines; polyoxyalkylene amides; and the like.

(10) Alcohol-based antifoaming agent Examples of the alcohol-based antifoaming agent include octyl alcohol, hexadecyl alcohol, acetylene alcohol, and glycols.

(11) Amide-based antifoaming agent Examples of the amide-based antifoaming agent include acrylate polyamine.

(12) Phosphate ester-based antifoaming agent Examples of phosphate ester-based antifoaming agents include tributyl phosphate, sodium octyl phosphate, and the like.

(13) Metal soap type antifoaming agent Examples of the metal soap type antifoaming agent include aluminum stearate and calcium oleate.

(14) Silicone-based antifoaming agent Examples of the silicone-based antifoaming agent include dimethyl silicone oil, silicone paste, silicone emulsion, organically modified polysiloxane (polyorganosiloxane such as dimethylpolysiloxane), and fluorosilicone oil. .

(15) AE agent Examples of the AE agent include resin soap, saturated or unsaturated fatty acid, sodium hydroxystearate, lauryl sulfate, ABS (alkyl benzene sulfonic acid), LAS (linear alkyl benzene sulfonic acid), alkane sulfonate, polyoxy Examples include ethylene alkyl (phenyl) ether, polyoxyethylene alkyl (phenyl) ether sulfate or a salt thereof, polyoxyethylene alkyl (phenyl) ether phosphate or a salt thereof, protein material, alkenyl sulfosuccinic acid, α-olefin sulfonate, and the like. It is done.

(16) Other surfactants Examples of other surfactants include intramolecular molecules such as aliphatic monohydric alcohols having 6 to 30 carbon atoms in the molecule such as octadecyl alcohol and stearyl alcohol, and abiethyl alcohol. 6 to 30 carbon atoms in the molecule such as alicyclic monohydric alcohol having 6 to 30 carbon atoms, monovalent mercaptan having 6 to 30 carbon atoms in the molecule such as dodecyl mercaptan, and nonylphenol Such as alkylphenols having a molecular weight such as dodecylamine, amines having 6-30 carbon atoms in the molecule, carboxylic acids having 6-30 carbon atoms in the molecule such as lauric acid and stearic acid, ethylene oxide, propylene oxide, etc. Polyalkylene oxide derivatives obtained by adding 10 moles or more of the above alkylene oxide; alkyl Alkyl diphenyl ether sulfonates having two phenyl groups having a sulfone group, which may have a substituent or an alkoxy group as a substituent, ether-bonded; various anionic surfactants; alkylamine acetate, alkyltrimethylammonium chloride, etc. Various cationic surfactants; various nonionic surfactants; various amphoteric surfactants;

(17) Waterproofing agent Examples of the waterproofing agent include fatty acids (salts), fatty acid esters, fats and oils, silicon, paraffin, asphalt, and wax.

(18) Rust preventive agent Examples of the rust preventive agent include nitrite, phosphate, zinc oxide and the like.

(19) Crack reducing agent Examples of the crack reducing agent include polyoxyalkyl ethers.

(20) Expanding material Examples of the expanding material include ettringite-based expanding material and coal-based expanding material.

  The cement admixture of the present invention is, for example, a cement wetting agent, a thickener, a separation reducing agent, an aggregating agent, in addition to the above other cement additives (materials), as long as the effects of the present invention are not impaired. Other components such as a drying shrinkage reducing agent, a strength enhancer, a self-leveling agent, a coloring agent, and an antifungal agent may be contained. As the blending ratio of the polycarboxylic acid copolymer for cement admixture of the present invention and such other components, any appropriate blending ratio can be adopted depending on the type and purpose of the other components used.

  Examples of particularly preferred embodiments of the cement admixture of the present invention include the following 1) to 7).

1) (1) A combination comprising essentially two components of the present invention, a polycarboxylic acid copolymer for cement admixture, and (2) an oxyalkylene antifoaming agent. The blending weight ratio of the oxyalkylene antifoaming agent (2) is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the polycarboxylic acid copolymer for cement admixture (1). Parts by weight.

2) (1) Polycarboxylic acid copolymer for cement admixture of the present invention, (2) polyalkylene having a polyoxyalkylene chain obtained by adding 2 to 300 average addition moles of alkylene oxide having 2 to 18 carbon atoms A copolymer comprising a glycol mono (meth) acrylic acid ester monomer, a (meth) acrylic acid monomer, and a monomer copolymerizable with these monomers (Japanese Patent Publication No. 59-18338) , JP-A-7-223852, JP-A-9-2441056, etc.), (3) A combination comprising essentially three components of an oxyalkylene antifoaming agent. In addition, the blending weight ratio of the polycarboxylic acid copolymer for cement admixture (1) and the copolymer (2) is preferably 5:95 to 95: 5, more preferably 10: 90-90: 10. The blending weight ratio of the oxyalkylene antifoaming agent (3) is 100 parts by weight of the total amount of the polycarboxylic acid copolymer for cement admixture (1) and the copolymer (2). On the other hand, it is preferably 0.01 to 10 parts by weight.

3) (1) A polycarboxylic acid copolymer for cement admixture of the present invention, and (2) a combination comprising essentially two components of a sulfonic acid dispersant having a sulfonic acid group in the molecule. Examples of the sulfonic acid dispersant include lignin sulfonate, naphthalene sulfonic acid formalin condensate, melamine sulfonic acid formalin condensate, polystyrene sulfonate, aminoaryl sulfonic acid-phenol-formaldehyde condensate and the like. An agent or the like can be used. The blending weight ratio of the polycarboxylic acid copolymer for cement admixture (1) and the sulfonic acid dispersant (2) is preferably 5:95 to 95: 5, more preferably 10: 90-90: 10.

4) (1) A combination comprising two components of a polycarboxylic acid copolymer for cement admixture of the present invention and (2) lignin sulfonate. The blending weight ratio of (1) the polycarboxylic acid copolymer for cement admixture and (2) lignin sulfonate is preferably 5:95 to 95: 5, more preferably 10 : 90-90: 10.

5) (1) A combination comprising essentially two components of the present invention, a polycarboxylic acid copolymer for cement admixture, and (2) a material separation reducing agent. As a material separation reducing agent, various thickeners such as nonionic cellulose ethers, a hydrophobic substituent consisting of a hydrocarbon chain having 4 to 30 carbon atoms as a partial structure and an alkylene oxide having 2 to 18 carbon atoms are added on average. A compound having a polyoxyalkylene chain having 2 to 300 moles added can be used. The blending weight ratio of the polycarboxylic acid copolymer for cement admixture (1) and the material separation reducing agent (2) is preferably 10:90 to 99.99: 0.01, More preferably, it is 50: 50-99.9: 0.1. A cement admixture comprising this combination is suitable for highly fluid concrete, self-filling concrete, self-leveling material and the like.

6) (1) A polycarboxylic acid copolymer for cement admixture according to the present invention, and (2) a combination comprising two components as a retarder. As the retarder, oxycarboxylic acids such as gluconic acid (salt) and citric acid (salt), sugars such as glucose, sugar alcohols such as sorbitol, phosphonic acids such as aminotri (methylenephosphonic acid), and the like can be used. . The blending weight ratio of the polycarboxylic acid copolymer for cement admixture (1) and the retarder (2) is preferably 50:50 to 99.9: 0.1, more preferably Is 70:30 to 99: 1.

7) (1) A polycarboxylic acid copolymer for cement admixture according to the present invention, and (2) a combination which essentially comprises two components of an accelerator. As the accelerator, soluble calcium salts such as calcium chloride, calcium nitrite and calcium nitrate, chlorides such as iron chloride and magnesium chloride, formates such as thiosulfate, formic acid and calcium formate, and the like can be used. The blending weight ratio of the polycarboxylic acid copolymer for cement admixture (1) to the accelerator (2) is preferably 10:90 to 99.9: 0.1, more preferably Is 20: 80-99: 1.

≪Cement composition≫
The cement composition of the present invention comprises the polycarboxylic acid copolymer for cement admixture of the present invention, cement and water.

  The cement composition of the present invention preferably comprises the cement admixture of the present invention, cement and water.

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

  The cement composition of the present invention may contain any appropriate aggregate such as fine aggregate (sand or the like) or coarse aggregate (crushed stone or the like).

  Examples of such aggregates include gravel, crushed stone, granulated slag, and recycled aggregate. Examples of such aggregates include refractory aggregates such as siliceous, clay, zircon, high alumina, silicon carbide, graphite, chromic, chromic, and magnesia.

  Any appropriate antifoaming agent may be included in the cement composition of the present invention. Examples of such an antifoaming agent include the various antifoaming agents described above.

In the cement composition of the present invention, any appropriate value can be set as the unit water amount per 1 m ³ , the amount of cement used, and the water / cement ratio. Such values, preferably, unit water is ^{100kg / m 3 ~185kg / m 3} , the amount of cement used is ^{250kg / m 3 ~800kg / m 3} , water / cement ratio (weight 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 ( (Weight ratio) = 0.15 to 0.65. As described above, the cement composition of the present invention can be widely used from poor blending to rich blending, and can be used for both high-strength concrete with a large amount of unit cement and poor blended concrete with a unit cement amount of 300 kg / m ³ or less. It is valid. Further, the cement composition of the present invention has a relatively high water reduction rate, that is, a water / cement ratio (weight ratio) = 0.15 to 0.5 (preferably 0.15 to 0.4). It can be used satisfactorily even in a region with a low cement ratio.

  As a content ratio of the polycarboxylic acid copolymer for cement admixture of the present invention in the cement composition of the present invention, any appropriate content ratio can be adopted depending on the purpose. As such a content ratio, when used for mortar or concrete using hydraulic cement, the content ratio of the polycarboxylic acid copolymer for cement admixture of the present invention with respect to 100 parts by weight of cement is preferably It is 0.01 weight part-10 weight part, More preferably, it is 0.02 weight part-5 weight part, More preferably, it is 0.05 weight part-3 weight part. By setting it as such a content rate, various favorable effects, such as reduction of unit water amount, an increase in intensity | strength, and an improvement in durability, are brought. If the content is less than 0.01 parts by weight, sufficient performance may not be exhibited. If the content is more than 10 parts by weight, the effect that can be achieved substantially reaches its peak and is also economical. May be disadvantageous.

  As the content ratio of the cement admixture of the present invention in the cement composition of the present invention, any appropriate content ratio can be adopted depending on the purpose. As such a content rate, as a content rate of the cement admixture of this invention with respect to 100 weight part of cement, Preferably it is 0.01 weight part-10 weight part, More preferably, it is 0.05 weight part-8 weight part. More preferably, it is 0.1 to 5 parts by weight. If the content is less than 0.01 parts by weight, sufficient performance may not be exhibited. If the content is more than 10 parts by weight, the effect that can be achieved substantially reaches its peak and is also economical. May be disadvantageous.

  The cement composition of the present invention may be effective for concrete secondary product concrete, centrifugal molding concrete, vibration compaction concrete, steam-cured concrete, shotcrete, and the like. The cement composition of the present invention may be effective for mortar and concrete that require high fluidity, such as high fluidity concrete, self-filling concrete, and self-leveling material.

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

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

<Weight average molecular weight>
Device: Waters Alliance (2695)
Analysis software: Emper professional + GPC option manufactured by Waters Column: TSKgel guard column (inner diameter 6.0 × 40 mm) + G4000SWXL + G3000SWXL + G2000SWXL (each inner diameter 7.8 × 300 mm)
Detector: differential refractometer (RI) detector (Waters 2414), multi-wavelength visible ultraviolet (PDA) detector (Waters 2996)
Eluent: A solution prepared by dissolving 115.6 g of sodium acetate trihydrate in a mixed solvent of 10999 g of ion-exchanged water and 6001 g of acetonitrile, and adjusting the pH to 6.0 with acetic acid.
Flow rate: 1.0 ml / min Column / detector temperature: 40 ° C
Measurement time: 45 minutes Sample solution injection amount: 100 μl (eluent solution with sample concentration of 0.5% by weight)
GPC standard sample: Polyethylene glycol manufactured by Tosoh Corporation Mp = 900000, 200000, 107000, 50000, 24000, 11840, 6450, 4250, 1470 are used.
Calibration curve: Created by a cubic equation using the Mp value of polyethylene glycol.

<Concrete test>
(Solid content measurement method)
The copolymer used for the performance test was measured for non-volatile content by the following procedure, and the concentration was calculated with the non-volatile content as the solid content (copolymer).
About 0.5 g of the copolymer aqueous solution was weighed in an aluminum cup, and about 1 g of ion-exchanged water was added to spread it uniformly. This was dried at 130 ° C. for 1 hour in a nitrogen atmosphere, and the nonvolatile content was measured from the weight difference before and after drying.
(Preparation of cement admixture)
It prepared using the copolymer, the antifoamer, and AE agent. A predetermined amount of the copolymer aqueous solution is weighed, and micro air 404 (manufactured by BASF Pozzolith) is added as an antifoaming agent, and micro air 202 (manufactured by BASF Pozzolith) is added as an AE agent, and the amount of air is 4.5 ± 0.5 vol. % To adjust.
The blending amount of the cement admixture relative to the weight of the hydraulic material (cement) was calculated as the solid content of the admixture (copolymer) and expressed in% (% by weight).
(Concrete test mix)
The blending unit amount is
Water: 172 kg / m ³ ,
Cement (manufactured by Taiheiyo Cement Co., Ltd .: ordinary Portland cement): 324 kg / m ³ ,
Coarse aggregate (Ome crushed stone): 938 kg / m ³ ,
Fine aggregate (from Oikawa / from Kimitsu = 80/20): 842 kg / m ³ .
(Preparation of cement composition)
Cement, fine aggregate and coarse aggregate are put into a 50 L forced kneading pan type mixer with the above composition, kneaded for 10 seconds, then water mixed with cement admixture is added, and further kneaded for 90 seconds, Concrete was manufactured. The slump flow value of the obtained concrete was performed in accordance with Japanese Industrial Standard (JIS A1101).

[Example 1]
A glass reaction vessel equipped with a thermometer, a stirrer, a dropping device, a nitrogen inlet tube, and a reflux condenser was charged with an average of 50 moles of ethylene oxide added to 303 parts of ion-exchanged water and 3-methyl-3-buten-1-ol. 487 parts of a saturated polyalkylene glycol ether monomer (IPN-50) and 6.7 parts of acrylic acid (AA) were charged, and the temperature was raised to 60 ° C. Next, 20.1 parts of acrylic acid (AA) and 16.2 parts of methyl acrylate (MA) are dropped into the reaction vessel over 3 hours. At the same time, 37.8 parts of ion-exchanged water is added with ammonium persulfate. An aqueous solution in which 24 parts were dissolved and an aqueous solution in which 0.63 parts of L-ascorbic acid and 1.06 parts of 2-mercaptopropionic acid were dissolved in 78.2 parts of ion-exchanged water were dropped over 3.5 hours. did. Thereafter, the temperature was continuously maintained at 60 ° C. for 1 hour to complete the polymerization reaction. Thereafter, the pH of the reaction solution was neutralized to pH = 7 using an aqueous sodium hydroxide solution at a temperature lower than the polymerization reaction temperature. In this way, an aqueous polymer solution containing the copolymer (1) was obtained. The weight average molecular weight Mw of the obtained copolymer (1) was 45000. The results are shown in Table 1.
The concrete test was done using the obtained copolymer (1). The results are shown in Table 2.

[Example 2]
Except having used ethyl acrylate (EA) instead of methyl acrylate (MA), it carried out similarly to Example 1 and obtained polymer aqueous solution containing a copolymer (2). The weight average molecular weight Mw of the obtained copolymer (2) was 46000. The results are shown in Table 1.
The concrete test was done using the obtained copolymer (2). The results are shown in Table 2.

Example 3
A polymer aqueous solution containing the copolymer (3) was obtained in the same manner as in Example 1 except that butyl acrylate (BA) was used instead of methyl acrylate (MA). The weight average molecular weight Mw of the obtained copolymer (3) was 46000. The results are shown in Table 1.
The concrete test was done using the obtained copolymer (3). The results are shown in Table 2.

Example 4
A polymer aqueous solution containing the copolymer (4) was obtained in the same manner as in Example 1 except that 2-ethylhexyl acrylate (2EHA) was used instead of methyl acrylate (MA). The obtained copolymer (4) had a weight average molecular weight Mw of 45,000. The results are shown in Table 1.
The concrete test was done using the obtained copolymer (4). The results are shown in Table 2.

Example 5
A glass reaction vessel equipped with a thermometer, a stirrer, a dropping device, a nitrogen inlet tube, and a reflux condenser was charged with an average of 50 moles of ethylene oxide added to 293 parts of ion-exchanged water and 3-methyl-3-buten-1-ol. 471 parts of a saturated polyalkylene glycol ether monomer (IPN-50) and 6.7 parts of acrylic acid (AA) were charged, and the temperature was raised to 60 ° C. Next, 20.1 parts of acrylic acid (AA) and 32.3 parts of butyl acrylate (BA) are dropped into the reaction vessel over 3 hours. At the same time, 30.9 parts of ion-exchanged water is added with ammonium persulfate. An aqueous solution in which 79 parts are dissolved and an aqueous solution in which 0.73 parts of L-ascorbic acid and 2.11 parts of 2-mercaptopropionic acid are dissolved in 70.5 parts of ion-exchanged water are dropped over 3.5 hours. did. Thereafter, the temperature was continuously maintained at 60 ° C. for 1 hour to complete the polymerization reaction. Thereafter, the pH of the reaction solution was neutralized to pH = 7 using an aqueous sodium hydroxide solution at a temperature lower than the polymerization reaction temperature. Thus, the polymer aqueous solution containing a copolymer (5) was obtained. The weight average molecular weight Mw of the obtained copolymer (5) was 30000. The results are shown in Table 1.
The concrete test was done using the obtained copolymer (5). The results are shown in Table 2.

Example 6
Instead of the unsaturated polyalkylene glycol ether monomer (IPN-50), an unsaturated polyalkylene glycol ether monomer (MLA) obtained by adding an average of 50 moles of ethylene oxide to 2-methyl-2-propen-1-ol. Except for using -50), the same procedure as in Example 1 was carried out to obtain a polymer aqueous solution containing the copolymer (6). The weight average molecular weight Mw of the obtained copolymer (6) was 44000. The results are shown in Table 1.
The concrete test was done using the obtained copolymer (6). The results are shown in Table 2.

[Comparative Example 1]
A glass reaction vessel equipped with a thermometer, a stirrer, a dropping device, a nitrogen inlet tube, and a reflux condenser was charged with an average of 50 moles of ethylene oxide added to 313 parts of ion-exchanged water and 3-methyl-3-buten-1-ol. 503 parts of a saturated polyalkylene glycol ether monomer (IPN-50) and 6.7 parts of acrylic acid (AA) were charged, and the temperature was raised to 60 ° C. Next, 20.1 parts of acrylic acid (AA) was dropped into the reaction vessel over 3 hours, and at the same time, an aqueous solution in which 2.7 parts of ammonium persulfate was dissolved in 64.8 parts of ion exchange water, and ion exchange An aqueous solution in which 0.52 part of L-ascorbic acid and 0.57 part of 2-mercaptopropionic acid were dissolved in 68.8 parts of water was dropped over 3.5 hours. Thereafter, the temperature was continuously maintained at 60 ° C. for 1 hour to complete the polymerization reaction. Thereafter, the pH of the reaction solution was neutralized to pH = 7 using an aqueous sodium hydroxide solution at a temperature lower than the polymerization reaction temperature. In this way, an aqueous polymer solution containing the copolymer (C1) was obtained. The obtained copolymer (C1) had a weight average molecular weight Mw of 52,000. The results are shown in Table 1.
The concrete test was done using the obtained copolymer (C1). The results are shown in Table 2.

[Comparative Example 2]
A glass reaction vessel equipped with a thermometer, a stirrer, a dripping device, a nitrogen inlet tube, and a reflux condenser was charged with 273 parts of ion-exchanged water and an average of 50 mol of ethylene oxide added to 3-methyl-3-buten-1-ol. 445 parts of a saturated polyalkylene glycol ether monomer (IPN-50) and 0.8 part of acrylic acid (AA) were charged, and the temperature was raised to 60 ° C. Next, 30.2 parts of acrylic acid (AA) and 54.0 parts of butyl acrylate (BA) are dropped into the reaction vessel over 3 hours, and at the same time, ammonium persulfate is added to 68.7 parts of ion-exchanged water. An aqueous solution in which 86 parts are dissolved and an aqueous solution in which 0.55 parts of L-ascorbic acid and 2.22 parts of 2-mercaptopropionic acid are dissolved in 123.1 parts of ion-exchanged water are dropped over 3.5 hours. did. Thereafter, the temperature was continuously maintained at 60 ° C. for 1 hour to complete the polymerization reaction. Thereafter, the pH of the reaction solution was neutralized to pH = 7 using an aqueous sodium hydroxide solution at a temperature lower than the polymerization reaction temperature. In this way, an aqueous polymer solution containing the copolymer (C2) was obtained. The weight average molecular weight Mw of the obtained copolymer (C2) was 32000. The results are shown in Table 1.
The concrete test was done using the obtained copolymer (C2). The results are shown in Table 2.

  It can be seen that the polycarboxylic acid copolymer for cement admixture obtained in the Examples has a flow loss as low as about 100 in the concrete test, and exhibits high fluidity over time.

  In the concrete test, the copolymer obtained in Comparative Example 1 has a flow loss over time as large as 117, and it can be seen that the fluidity retention with time is lower than that in Examples.

  It can be seen that the copolymer obtained in Comparative Example 2 has poor fluidity immediately after kneading in the concrete test, and the fluidity is poor immediately after kneading even if the amount added is larger than that in Examples. .

  The polycarboxylic acid copolymer for cement admixture of the present invention is suitably used as a cement admixture. The cement admixture is suitably used for cement compositions such as cement paste, mortar, and concrete.

Claims (8)

A polycarboxylic acid copolymer for cement admixture,
The copolymer includes an unsaturated polyalkylene glycol ether monomer (a) -derived structural unit (I) represented by general formula (1) and an unsaturated carboxylic acid represented by general formula (2). A structural unit (II) derived from a monomer (b) and a structural unit (III) derived from an unsaturated carboxylic acid ester monomer (c),
The content of the structural unit (I) derived from the monomer (a) in the copolymer is 44% by weight to 98% by weight,
The content ratio of the structural unit (II) derived from the monomer (b) in the copolymer is 1% by weight to 49% by weight,
The content of the structural unit (III) derived from the monomer (c) in the copolymer is 1% by weight to 7% by weight.
Polycarboxylic acid copolymer for cement admixture.

(In General Formula (1), Y represents an alkenyl group having 2 to 10 carbon atoms, R ¹ O represents one or more of oxyalkylene groups having 2 to 18 carbon atoms, and R ² represents a hydrogen atom or Represents an alkyl group having 1 to 18 carbon atoms, and m is an average added mole number of an oxyalkylene group and is 1 to 500.)

(In General Formula (2), R ³ , R ⁴ , and R ⁵ are the same or different and represent a hydrogen atom, a methyl group, or — (CH ₂ ) _n COOM ² group, and n is 0 to 2, M ¹ and M ² are the same or different and each represents a hydrogen atom, a metal atom, an ammonium group, or an organic amine group, and R ⁴ and R ⁵ are not simultaneously a — (CH ₂ ) _n COOM ² group, ^{When 5} is a — (CH ₂ ) _n COOM ² group, R ³ and R ⁴ are the same or different and are a hydrogen atom or a methyl group.)   The polycarboxylic acid copolymer for cement admixture according to claim 1, wherein Y in the general formula (1) is an alkenyl group having 4 to 5 carbon atoms. In the general formula (2), R ³ and R ⁴ are both hydrogen atoms, and R ⁵ is a hydrogen atom or a methyl group. The polycarboxylic acid copolymer for cement admixture according to claim 1 or 2 Coalescence. The polycarboxylic acid copolymer for cement admixture according to any one of claims 1 to 3, wherein the unsaturated carboxylic acid ester monomer (c) is represented by the general formula (3).

(In General Formula (3), R ⁶ , R ⁷ , and R ⁸ are the same or different and represent a hydrogen atom or a methyl group, and R ⁹ represents a hydrocarbon group having 1 to 18 carbon atoms.) The polycarboxylic acid copolymer for a cement admixture according to claim 4, wherein R ⁹ in the general formula (3) is a hydrocarbon group having 1 to 8 carbon atoms.   The cement admixture according to any one of claims 1 to 5, wherein a content ratio of the structural unit (III) derived from the monomer (c) in the copolymer is 2% by weight to 7% by weight. Polycarboxylic acid copolymer.   A cement admixture comprising the polycarboxylic acid copolymer for cement admixture according to any one of claims 1 to 6. A cement composition comprising the polycarboxylic acid copolymer for cement admixture according to any one of claims 1 to 6, cement and water.