JP2017075076A - Additive for cement and cement composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an additive for cement capable of suppressing by-production of mirabilite and reducing a used amount for achieving same retention ratio when made as a cement composition, and the cement composition containing the additive for cement.SOLUTION: An additive for cement contains specific polycarboxylic acid copolymer having a constitutional unit (I) derived from an unsaturated polyalkylene glycol monomer (a) and a constitutional unit (II) derived from an unsaturated carboxylic acid monomer (b), wherein 10 to 65 mol% of the total amount of carboxylic acid in the unsaturated carboxylic acid monomer (b) is alkanolamine salt of carboxylic acid and 0 to 90 mol% of the total amount of carboxylic acid in the unsaturated carboxylic acid monomer (b) is an alkali metal salt or an alkali earth metal.SELECTED DRAWING: None

Description

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

  Cement compositions such as mortar and concrete generally include cement, aggregate, and water, and further include a cement additive that preferably functions as a water reducing agent to increase fluidity and reduce water (eg, Patent Document 1).

  Reducing the amount of cement additive that functions as a water reducing agent as much as possible is one of the important factors in preparing a cement composition from the viewpoint of cost and the like.

In addition, when a specific polycarboxylic acid copolymer is used as a polymer component of an additive for cement, a persulfate is used as an initiator in the production of the copolymer, and neutralization after polymerization is performed. It is common to use NaOH. However, when NaOH is used for neutralization after polymerization, bow glass (Na ₂ SO ₄ ) is produced as a by-product, which causes troubles such as crystallization of the glass powder and clogging of various devices at low temperatures. . On the other hand, if neutralization is not performed after polymerization in order to suppress the by-product of bow glass, the problem arises that the acidity increases and the various devices are corroded.

JP2013-133241A

  The subject of this invention is providing the additive for cement which can suppress the byproduct of a bow glass and can reduce the usage-amount for achieving the same fluidity | liquidity when it is set as a cement composition. Moreover, it is providing the cement composition containing such a cement additive.

（一般式（１）中、Ｒ^１およびＲ^２は、同一または異なって、水素原子またはメチル基を表し、Ｒ^３は、水素原子または炭素原子数１〜３０の炭化水素基を表し、ＡＯは、炭素原子数２〜１８のオキシアルキレン基を表し、ｎは、ＡＯで表されるオキシアルキレン基の平均付加モル数を表し、ｎは１〜９０の整数であり、ｘは０〜２の整数である。）

（一般式（２）中、Ｒ^４〜Ｒ^６は、同一または異なって、水素原子、メチル基、または−（ＣＨ_２）_ｚＣＯＯＭ基を表し、−（ＣＨ_２）_ｚＣＯＯＭ基は−ＣＯＯＸ基または他の−（ＣＨ_２）_ｚＣＯＯＭ基と無水物を形成していても良く、ｚは０〜２の整数であり、Ｍは、水素原子、アルカリ金属、アルカリ土類金属、アンモニウム基、有機アンモニウム基、または有機アミン基を表し、Ｘは、水素原子、メチル基、エチル基、アルカリ金属、アルカリ土類金属、アンモニウム基、有機アンモニウム基、または有機アミン基を表す。） The cement additive of the present invention is
Derived from the structural unit (I) derived from the unsaturated polyalkylene glycol monomer (a) represented by the general formula (1) and the unsaturated carboxylic acid monomer (b) represented by the general formula (2) A polycarboxylic acid copolymer having the structural unit (II):
10 mol% to 65 mol% in the total amount of —COOM group and —COOX group in the general formula (2) is an alkanolamine salt,
In the total amount of —COOM groups and —COOX groups in the general formula (2), 0 mol% to 90 mol% are alkali metal salts or alkaline earth metal salts.

(In General Formula (1), R ¹ and R ² are the same or different and each represents a hydrogen atom or a methyl group; R ³ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms; Represents an oxyalkylene group having 2 to 18 carbon atoms, n represents the average number of added moles of the oxyalkylene group represented by AO, n is an integer of 1 to 90, and x is an integer of 0 to 2 .)

(In general formula (2), R ^{4 to} R ⁶ are the same or different and each represents a hydrogen atom, a methyl group, or — (CH ₂ ) _z COOM group, and — (CH ₂ ) _z COOM group represents a —COOX group. Or other — (CH ₂ ) _z COOM group may form an anhydride, z is an integer of 0 to 2, M is a hydrogen atom, alkali metal, alkaline earth metal, ammonium group, organic An ammonium group or an organic amine group is represented, and X represents a hydrogen atom, a methyl group, an ethyl group, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group.)

  In one embodiment, the total of the alkanolamine salt, the alkali metal salt, and the alkaline earth metal salt in the total amount of —COOM group and —COOX group in the general formula (2) is 10 mol% to 100%. Mol%.

  The cement composition of the present invention contains the cement additive of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the additive for cement which can suppress the byproduct of a bow glass and can reduce the usage-amount for achieving the same fluidity | liquidity when it is set as a cement composition can be provided. Moreover, the cement composition containing such a cement additive can be provided.

  In the present specification, the expression “(meth) acryl” means “acryl and / or methacryl”, and the expression “(meth) acrylate” means “acrylate and / or methacrylate”. Means “allyl and / or methallyl”, and “(meth) acrolein” means “acrolein and / or methacrole”. It means "rain". Further, in the present specification, the expression “acid (salt)” means “acid and / or salt thereof”. In addition, when there is an expression “mass” in the present specification, it may be read as “weight” conventionally used as a unit of weight in general, and conversely, “weight” in the present specification. May be read as “mass”, which is commonly used as an SI system unit indicating weight.

≪Cement additive≫
The cement additive of the present invention comprises an unsaturated polyalkylene glycol monomer (a) represented by the general formula (1) and the unsaturated carboxylic acid represented by the general formula (2). A polycarboxylic acid copolymer having a structural unit (II) derived from the acid monomer (b).

  The cement additive of the present invention may contain any appropriate other component as long as the effects of the present invention are not impaired. The content ratio of the polycarboxylic acid copolymer in the cement additive of the present invention is preferably 50% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, and still more preferably. It is 90% by mass to 100% by mass, particularly preferably 95% by mass to 100% by mass, and most preferably substantially 100% by mass.

<Polycarboxylic acid copolymer>
The polycarboxylic acid-based copolymer contained in the cement additive of the present invention includes the structural unit (I) derived from the unsaturated polyalkylene glycol monomer (a) represented by the general formula (1) and the general formula. And a structural unit (II) derived from the unsaturated carboxylic acid monomer (b) represented by (2).

The structural unit (I) derived from the unsaturated polyalkylene glycol monomer (a) represented by the general formula (1) is specifically represented by the following formula.

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

In general formula (1) and structural unit (I), R ¹ and R ² are the same or different and each represents a hydrogen atom or a methyl group.

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

  In the general formula (1) and the structural unit (I), AO is an oxyalkylene group having 2 to 18 carbon atoms, preferably an oxyalkylene group having 2 to 8 carbon atoms, more preferably the number of carbon atoms. 2 to 4 oxyalkylene groups. When AO is any two or more selected from oxyethylene group, oxypropylene group, oxybutylene group, oxystyrene group, etc., the addition form of AO is random addition, block addition, alternating addition, etc. Either form may be sufficient. In order to secure a balance between hydrophilicity and hydrophobicity, it is preferable that the oxyalkylene group contains an oxyethylene group as an essential component, and more than 50 mol% of the entire oxyalkylene group is an oxyethylene group. Preferably, 90 mol% or more of the entire oxyalkylene group is more preferably an oxyethylene group, and 100 mol% or more of the entire oxyalkylene group is particularly preferably an oxyethylene group.

  In the general formula (1) and the structural unit (I), n represents the average added mole number of the oxyalkylene group represented by AO (sometimes referred to as “chain length”), preferably 1 to 90, Is 2 to 70, more preferably 3 to 60, still more preferably 4 to 50, particularly preferably 5 to 40, and most preferably 6 to 30. When n is within the above range, when used as a cement composition, the amount used to achieve the same retention rate can be greatly reduced, and both excellent water reduction and excellent retention can be achieved. An additive for cement that functions as a water reducing agent can be provided.

  In general formula (1) and structural unit (I), x is an integer of 0-2.

  As the unsaturated polyalkylene glycol monomer (a) represented by the general formula (1), for example, an alkylene oxide having 2 to 8 carbon atoms is added to a saturated aliphatic alcohol having 1 to 20 carbon atoms. Obtained by polymerizing an alkylene oxide having 2 to 18 carbon atoms with an ester of an alkoxypolyalkylene glycol obtained by this method and (meth) acrylic acid or crotonic acid; a saturated aliphatic alcohol having 1 to 20 carbon atoms Esterified products of polyalkylene glycols and (meth) acrylic acid or crotonic acid; C 3-20 unsaturated aliphatic alcohols such as (meth) allyl alcohol, crotyl alcohol, oleyl alcohol, etc. Polyalkylene glycols obtained by adding 2 to 8 alkylene oxides; ) Esterification product with acrylic acid or crotonic acid; C2-C18 alkylene oxide is polymerized on C3-C20 unsaturated aliphatic alcohols such as (meth) allyl alcohol, crotyl alcohol, oleyl alcohol, etc. Esterified product of polyalkylene glycols obtained in this way with (meth) acrylic acid or crotonic acid; C 2-8 alkylene oxides are added to C 3-20 alicyclic alcohols such as cyclohexanol Esterified product of polyalkylene glycols obtained by the above and (meth) acrylic acid or crotonic acid; polymerization of C 2-18 alkylene oxides on C 3-20 alicyclic alcohols such as cyclohexanol And poly (alkylene glycols) obtained by Is an esterified product of crotonic acid; polyalkylene glycols obtained by adding alkylene oxides having 2 to 8 carbon atoms to aromatic alcohols having 6 to 20 carbon atoms; and (meth) acrylic acid or crotonic acid; Esterified products of polyalkylene glycols obtained by polymerizing alkylene oxides having 2 to 18 carbon atoms on aromatic alcohols having 6 to 20 carbon atoms and (meth) acrylic acid or crotonic acid; Is mentioned.

  The unsaturated polyalkylene glycol monomer (a) represented by the general formula (1) is preferably an alkoxy polyalkylene glycol of (meth) acrylic acid in that the effects of the present invention can be further exhibited. Ester.

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

In general formula (2) and structural unit (II), R ^{4 to} R ⁶ are the same or different and each represents a hydrogen atom, a methyl group, or a — (CH ₂ ) _z COOM group. The — (CH ₂ ) _z COOM group may form an anhydride with the —COOX group or other — (CH ₂ ) _z COOM groups. z is an integer of 0-2.

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

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

In the general formula (2) and the structural unit (II), as described later, since an alkanolamine salt of a carboxyl group is essential, R ^{4 to} R in the general formula (2) and the structural unit (II). All of the ⁶ and -COOX groups are not other than the carboxyl group alkanolamine salt (for example, when R ^{4 to} R ⁶ are all methyl groups and the -COOX group X is a methyl group).

  Examples of the unsaturated carboxylic acid monomer (b) represented by the general formula (2) include monocarboxylic acid monomers such as (meth) acrylic acid and crotonic acid or salts thereof; maleic acid, And dicarboxylic acid monomers such as itaconic acid and fumaric acid or salts thereof; anhydrides of dicarboxylic acid monomers such as maleic acid, itaconic acid and fumaric acid or salts thereof; and the like. Examples of the salt herein include alkali metal salts, alkaline earth metal salts, ammonium salts, organic ammonium salts, and organic amine salts.

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

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

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

  The unsaturated carboxylic acid monomer (b) represented by the general formula (2) is preferably (meth) acrylic acid, maleic acid, maleic anhydride in that the effects of the present invention can be further exhibited. More preferred are acrylic acid and methacrylic acid.

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

  In the present invention, the content of the alkanolamine salt is 10 mol% to 65 mol%, preferably 10 mol% to 60 mol% in the total amount of —COOM group and —COOX group in the general formula (2). More preferably 11 mol% to 55 mol%, still more preferably 12 mol% to 50 mol%, particularly preferably 13 mol% to 45 mol%, most preferably 12 mol% to 40 mol%. %. If the content of the alkanolamine salt in the total amount of -COOM group and -COOX group in the general formula (2) is within the above range, it is possible to further suppress the by-product of bow glass and suppress the corrosiveness of various apparatuses. be able to.

  In the present invention, the content of alkali metal salt or alkaline earth metal salt is 0 mol% to 90 mol% in the total amount of —COOM group and —COOX group in the general formula (2), more preferably 10 It is from mol% to 85 mol%, more preferably from 20 mol% to 80 mol%, particularly preferably from 30 mol% to 75 mol%, and most preferably from 35 mol% to 70 mol%. If the content of the alkali metal salt or alkaline earth metal salt in the total amount of —COOM group and —COOX group in the general formula (2) is within the above range, the by-product of the bow glass can be further suppressed, and various devices The corrosiveness of can be suppressed.

  In the present invention, the total content of alkanolamine salt, alkali metal salt and alkaline earth metal salt in the total amount of —COOM group and —COOX group in general formula (2) is preferably 10 mol% to 100 mol. Mol%, more preferably 30 mol% to 97 mol%, still more preferably 50 mol% to 95 mol%, particularly preferably 70 mol% to 93 mol%, most preferably 80 mol%. -90 mol%. If the total content of the alkanolamine salt, the alkali metal salt, and the alkaline earth metal salt in the total amount of —COOM group and —COOX group in the general formula (2) is within the above range, the by-product of the bow nitrate is generated. It can suppress more and can suppress the corrosivity of various apparatuses.

  The content ratio of the structural unit (I) in the polycarboxylic acid copolymer contained in the cement additive of the present invention is preferably 30% by mass to 99% by mass, more preferably 40% by mass to 95%. % By mass, more preferably 50% by mass to 90% by mass, particularly preferably 60% by mass to 85% by mass, and most preferably 70% by mass to 80% by mass. If the content ratio of the structural unit (I) in the polycarboxylic acid copolymer contained in the cement additive of the present invention is within the above range, the same fluidity can be achieved when a cement composition is used. It is possible to provide an additive for cement that can further reduce the amount used.

  The content ratio of the structural unit (II) in the polycarboxylic acid copolymer contained in the cement additive of the present invention is preferably 1% by mass to 70% by mass, more preferably 5% by mass to 60% by mass. % By mass, more preferably 10% by mass to 50% by mass, particularly preferably 15% by mass to 40% by mass, and most preferably 20% by mass to 30% by mass. If the content ratio of the structural unit (II) in the polycarboxylic acid copolymer contained in the additive for cement of the present invention is within the above range, the same fluidity can be achieved when the cement composition is used. It is possible to provide an additive for cement that can further reduce the amount used.

  The total content of the structural unit (I) and the structural unit (II) in the polycarboxylic acid copolymer contained in the cement additive of the present invention is preferably 50% by mass to 100% by mass. , More preferably 70% by mass to 100% by mass, further preferably 90% by mass to 100% by mass, particularly preferably 95% by mass to 100% by mass, and most preferably substantially 100% by mass. is there. If the total content ratio of the structural unit (I) and the structural unit (II) in the polycarboxylic acid copolymer contained in the cement additive of the present invention is within the above range, the by-product of the bow glass is generated. It is possible to provide an additive for cement that can be further suppressed and that can reduce the amount of use for achieving the same retention when a cement composition is used.

  In the polycarboxylic acid copolymer contained in the additive for cement of the present invention, in addition to the structural unit (I) and the structural unit (II), the structural unit (III) derived from another monomer (c). May be included.

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

  As the monomer (c), for example, hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate; unsaturated monomethyl such as methyl (meth) acrylate and glycidyl (meth) acrylate Esters of carboxylic acids and alcohols having 1 to 30 carbon atoms; (anhydrous) Half esters of unsaturated dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid and alcohols having 1 to 30 carbon atoms; ) Diesters of unsaturated dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid and alcohols having 1 to 30 carbon atoms; half amides of the above unsaturated dicarboxylic acids and amines having 1 to 30 carbon atoms; Diamides of unsaturated dicarboxylic acids and amines having 1 to 30 carbon atoms; Half esters of an alkyl (poly) alkylene glycol obtained by adding 1 to 500 moles of an alkylene oxide having 2 to 18 carbon atoms to an amine or an amine; and the above unsaturated dicarboxylic acids; Diesters of alkyl (poly) alkylene glycols having 1 to 500 moles of alkylene oxide added thereto and the above unsaturated dicarboxylic acids; the above unsaturated dicarboxylic acids and glycols having 2 to 18 carbon atoms or the number of moles of these glycols added Half-esters with 2-500 polyalkylene glycols; diesters of unsaturated dicarboxylic acids with 2-18 carbon atoms or polyalkylene glycols with 2 to 500 addition moles of these glycols; Glyco with 2 to 18 carbon atoms Or half-amides of these glycols with polyalkylene glycols having an addition mole number of 2 to 500; (poly) alkylene glycols such as (poly) ethylene glycol di (meth) acrylate and (poly) propylene glycol di (meth) acrylate Di (meth) acrylates; polyfunctional (meth) acrylates such as hexanediol di (meth) acrylate and trimethylolpropane tri (meth) acrylate; (poly) alkylene glycol dimaleates such as polyethylene glycol dimaleate; vinyl sulfonate , (Meth) allyl sulfonate, 2-methylpropanesulfonic acid (meth) acrylamide, unsaturated sulfonic acids (salts) such as styrene sulfonic acid; unsaturated monocarboxylic acids such as methyl (meth) acrylamide and 1 carbon atom Amides with -30 amines; vinyl aromatics such as styrene, α-methylstyrene, vinyltoluene; alkanediol mono (meth) acrylates such as 1,4-butanediol mono (meth) acrylate; butadiene, isoprene Dienes such as; (meth) acrylic (alkyl) amides, unsaturated amides such as N-methylol (meth) acrylamide, N, N-dimethyl (meth) acrylamide; unsaturated cyanides such as (meth) acrylonitrile; acetic acid Unsaturated esters such as vinyl; Unsaturated amines such as aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate and vinylpyridine; Divinyl aromatics such as divinylbenzene; (meth) allyl alcohol, glycidyl Allyls such as (meth) allyl ether; (methoxy) polyethylene Vinyl ethers such as glycol monomethyl ether; (methoxy) polyethylene glycol mono (meth) allyl ether (meth) allyl ethers; and the like.

  The content ratio of the structural unit (III) in the polycarboxylic acid copolymer that can be included in the cement additive of the present invention is preferably 0% by mass to 50% by mass, more preferably 0% by mass to It is 40% by mass, more preferably 0% by mass to 30% by mass, particularly preferably 0% by mass to 20% by mass, and most preferably 0% by mass to 10% by mass. If the content ratio of the structural unit (III) in the polycarboxylic acid copolymer that can be contained in the cement additive of the present invention is within the above range, the same fluidity can be achieved in the case of a cement composition. It is possible to provide an additive for cement that can further reduce the amount of use.

  In the polycarboxylic acid copolymer contained in the cement additive of the present invention, the content ratio of the structural unit (I), the content ratio of the structural unit (II), the structural unit (I) and the structural unit (II) For example, various structural analyzes of the polycarboxylic acid copolymer, for example, the content ratio of the structural unit (III) in the polycarboxylic acid copolymer contained in the additive for cement of the present invention (For example, NMR). Further, it is calculated based on the use amount of various monomers used in producing the polycarboxylic acid-based copolymer contained in the additive for cement of the present invention without performing the above various structural analyses. In the polycarboxylic acid copolymer contained in the cement additive of the present invention, the content ratio of the structural unit (I) and the structural unit (II) The content ratio, the total content ratio of the structural unit (I) and the structural unit (II), the content ratio of the structural unit (III) in the polycarboxylic acid copolymer contained in the cement additive of the present invention, etc. Also good. That is, for example, unsaturated polyalkylene glycol monomer (a) and unsaturated in all monomer components used in producing the polycarboxylic acid copolymer contained in the cement additive of the present invention. The content ratio of the total mass with the carboxylic acid monomer (b) is the structural unit (I) and structural unit (II) in the polycarboxylic acid copolymer contained in the cement additive of the present invention. And may be treated as the total content ratio.

  When determining the content ratio of the structural unit in the polycarboxylic acid copolymer contained in the additive for cement of the present invention, if the structural unit has a carboxyl group salt, all of the acid part of the carboxyl group Calculated in terms of sodium salt.

  The mass average molecular weight (Mw) of the polycarboxylic acid-based copolymer contained in the cement additive of the present invention is preferably 2000 to 1000000, more preferably 5000 to 900000, and further preferably 10000 to 700000. Yes, particularly preferably 15,000 to 600,000, most preferably 25,000 to 100,000.

  In the cement additive of the present invention, the pH of the aqueous solution adjusted so that the concentration of the solid content contained in the additive is 40% by mass is preferably 4.0 to 10.0, and more preferably 5.0 to 10.0. 9.0, more preferably 5.5 to 8.0, particularly preferably 6.0 to 7.5, and most preferably 6.5 to 7.0. If the pH is within the above range, the problem that the acidity becomes strong and the various devices are corroded can be reduced.

  The polycarboxylic acid copolymer contained in the cement additive of the present invention can be produced by any appropriate method within a range not impairing the effects of the present invention. The polycarboxylic acid-based copolymer contained in the cement additive of the present invention is preferably a single copolymer containing an unsaturated polyalkylene glycol-based monomer (a) and an unsaturated carboxylic acid-based monomer (b). Polymerization of the monomer component can be carried out in the presence of a polymerization initiator.

  Unsaturated polyalkylene glycol monomer (a), unsaturated carboxylic acid monomer (b) that can be used for the production of the polycarboxylic acid copolymer contained in the cement additive of the present invention, and necessary Accordingly, the amount of the other monomer (c) used is a structural unit derived from each monomer in all the structural units constituting the polycarboxylic acid copolymer contained in the cement additive of the present invention. What is necessary is just to adjust suitably so that the ratio may become what was mentioned above. Preferably, assuming that the polymerization reaction proceeds quantitatively, the proportion of structural units derived from each monomer in all the structural units constituting the polycarboxylic acid copolymer contained in the cement additive of the present invention described above Each monomer may be used in the same proportion as.

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

  The amount of the polymerization initiator is preferably 0.1% by mass to 2.5% by mass, and more preferably 0.15% by mass with respect to the total amount of monomers, from the viewpoint of polymerizability and by-product generation of bow glass. % By mass to 2.0% by mass, more preferably 0.2% by mass to 1.5% by mass, particularly preferably 0.3% by mass to 1.0% by mass, and most preferably 0.8% by mass. It is 4 mass%-0.7 mass%.

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

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

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

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

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

  In the produced polycarboxylic acid copolymer, it is preferable to adjust the pH of the reaction solution after the production of the polycarboxylic acid copolymer to 4 or more from the viewpoint of handleability. However, in order to improve the polymerization rate, it is preferable to perform the polymerization at a pH of less than 4 and adjust the pH to 4 or more after the polymerization.

  The produced polycarboxylic acid-based copolymer can be subjected to concentration adjustment, if necessary, with respect to the solution obtained by the production.

  The produced polycarboxylic acid copolymer may be used as it is in the form of a solution, or may be used after powdered.

≪Cement composition≫
The cement composition of the present invention contains the cement additive of the present invention.

  In addition to the cement additive of the present invention, the cement composition of the present invention preferably contains cement, water, and aggregate, and more preferably contains cement, water, aggregate, and cement admixture.

  The content of the cement additive of the present invention in the cement composition of the present invention is preferably 0.001% by mass to 1% by mass, more preferably 0.005% by mass, based on the solid content of the cement. % To 0.9% by mass, more preferably 0.01% to 0.8% by mass, particularly preferably 0.01% to 0.7% by mass, and most preferably 0.01% to 0.9% by mass. It is mass%-0.5 mass%.

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

  The cement admixture preferably contains a polymer for cement admixture in that the effects of the present invention can be expressed more effectively.

  The cement admixture may contain any appropriate other component in addition to the cement admixture polymer as long as the effects of the present invention are not impaired.

  Examples of other components include a cement dispersant. When cement dispersant is used, the blending ratio of polymer for cement admixture and cement dispersant (cement admixture polymer / cement dispersant) is different in the type of cement dispersant used, blending conditions, test conditions, etc. Can set any appropriate blending ratio. 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 other than the polycarboxylic acid-based copolymer contained in the cement dispersant composition of the present invention. Can be mentioned.

  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, 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;

  The cement admixture 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 (12). The mixing ratio of the polymer for cement admixture that can be included in the cement admixture and such other cement additives (materials) is arbitrarily appropriate depending on the type and purpose of the other cement additives (materials) to be used. Various mixing ratios can be employed.

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

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

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

  In addition, as a ratio of the hardening retarder with respect to a compound (A), Preferably they are 1 mass%-10000 mass%, More preferably, they are 5 mass%-1000 mass%, More preferably, they are 10 mass%-500 mass%. Especially preferably, it is 30 mass%-300 mass%, Most preferably, it is 50 mass%-200 mass%.

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

(5) Oxyalkylene-based antifoaming agent: polyoxyalkylenes such as (poly) oxyethylene (poly) oxypropylene adducts; polyoxyalkylene alkyl ethers such as diethylene glycol heptyl ether; polyoxyalkylene acetylene ethers; ) Oxyalkylene fatty acid esters; polyoxyalkylene sorbitan fatty acid esters; polyoxyalkylene alkyl (aryl) ether sulfate salts; polyoxyalkylene alkyl phosphate esters; polyoxypropylene polyoxyethylene laurylamine (propylene oxide 1-20) Mole additions, ethylene oxide 1-20 mol adducts, etc.), fatty acid-derived amines obtained from cured beef tallow added with alkylene oxide (propylene oxide 1-20 mol) Additionally, polyoxyalkylene alkyl amines ethylene oxide 20 mol adduct) or the like; polyoxyalkylene amide.

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

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

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

(9) Waterproofing agent: fatty acid (salt), fatty acid ester, fats and oils, silicon, paraffin, asphalt, wax and the like.

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

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

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

  Other known cement additives (materials) include cement wetting agents, thickeners, separation reducing agents, flocculants, drying shrinkage reducing agents, strength enhancers, self-leveling agents, rust preventives, colorants, and antifungal agents. An agent etc. can be mentioned. These known cement additives (materials) may be only one kind or two or more kinds.

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

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

  When the cement composition of the present invention contains a polymer for cement admixture, any appropriate content ratio may be adopted as the content of the polymer for cement admixture in the cement composition of the present invention depending on the purpose. obtain. As such a content ratio, when used for mortar or concrete using hydraulic cement, the content ratio of the polymer for cement admixture with respect to 100 parts by mass of cement is preferably 0.01 parts by mass to 10 parts by mass. More preferably, it is 0.02 mass part-5 mass parts, More preferably, it is 0.05 mass part-3 mass parts. 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 about. When the content ratio is less than 0.01 parts by mass, sufficient performance may not be exhibited. When the content ratio exceeds 10 parts by mass, the effect that can be achieved substantially reaches its peak and also from the economical aspect. May be disadvantageous.

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

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

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

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

<Mass average molecular weight analysis conditions>
The mass average molecular weight was measured under the following conditions.
Device: Waters Alliance (2695)
Analysis software: Waters, Empor professional + GPC option column: Tosoh, TSKguardcolumns SWXL + TSKgel G4000SWXL + G3000SWXL + G2000SWXL
Detector: differential refractometer (RI) detector (Waters 2414), multi-wavelength visible ultraviolet (PDA) detector (Waters 2996)
Eluent: A solution obtained by dissolving 115.6 g of sodium acetate trihydrate in a mixed solvent of 10999 g of water and 6001 g of acetonitrile, and adjusting the pH to 6.0 with acetic acid.
Standard substance for preparing calibration curve: polyethylene glycol (peak top molecular weight (Mp) 272500, 219300, 107000, 50000, 24000, 12600, 7100, 4250, 1470)
Calibration curve: Prepared by a cubic equation based on the Mp value and elution time of the polyethylene glycol.
Flow rate: 1 mL / min Column temperature: 40 ° C
Measurement time: 45 minutes Sample solution injection amount: 100 μL

<Evaluation of amount of by-product of bow glass>
The cement additive obtained in Examples and Comparative Examples was used as an aqueous solution prepared so that the concentration of the solid content contained in the cement additive was 40% by mass, and the amount of by-product of bow glass was observed at 2 ° C. did. In accordance with the following criteria, the amount of by-product of bow glass was evaluated.
A: By-product of bow glass was not observed.
◯: Only a slight amount of bow glass was observed.
×: Many by-products of bow glass were observed.

<Mortar test conditions>
A kneader for mechanical kneading, a spoon, a flow table, a flow cone, and a stick according to JIS-R5201-1997 were used. At this time, unless otherwise specified, a mortar test was performed in accordance with JIS-R5201-1997.
The materials and mortar used in the test consisted of 587 g of ordinary Portland cement manufactured by Taiheiyo Cement Co., 1350 g of standard sand for cement strength test in accordance with JIS-R5201-1997, an aqueous solution of a polymer for cement admixture and an antifoaming agent. 264 g of ion exchange water. The antifoaming agent was added for the purpose of avoiding the influence of air bubbles on the strength of the mortar composition so that the amount of air was 3.0% or less. Specifically, the oxyalkylene antifoaming agent was used in an amount that would be 0.1% with respect to the cement admixture copolymer. When the amount of air in the mortar is larger than 3.0%, the amount of the antifoaming agent is adjusted so that the amount of air becomes 3.0% or less.
The mortar was prepared at room temperature (20 ± 2 ° C.) using a Hobart mortar mixer (model number N-50, manufactured by Hobart) for 4 minutes and 30 seconds. Specifically, a prescribed amount of cement was placed in a kneading bowl, attached to a kneader and started at a low speed. 15 seconds after starting the paddle, a specified amount of cement admixture polymer and water containing antifoam was added for 15 seconds. After that, sand was added and kneaded at a low speed for 30 seconds, then at a high speed and continued to be kneaded for 30 seconds. Remove the kneader from the kneader and stop kneading for 120 seconds, then attach the kneader again to the kneader and knead for 60 seconds at high speed (4 minutes 30 minutes after starting at the first low speed) After a second), the mixture was stirred 10 times each with a spoon. The kneaded mortar was packed in two layers on a flow cone placed on a flow table. Each layer is struck 15 times over the entire surface so that the tip of the stab stick is about half the depth of the layer, and finally, the shortage is compensated, the surface is smoothed, and the start is started at a low speed first. 6 minutes after that, the flow cone was lifted and removed vertically, 15 times of falling motion was given for 15 seconds, the diameter of the mortar spread on the table was measured in two directions, and this average value was taken as the flow value.
After kneading, the flow value and the amount of air were measured to prepare a sample for compressive strength test, and the compressive strength after 28 days was measured under the following conditions.
Specimen creation: 50mm x 100mm
Specimen curing (28 days): Temperature 20 ° C, humidity 60%, constant temperature and humidity air curing for 24 hours, then curing the specimen in water for 27 days: Specimen surface polishing (use specimen polishing finish machine)
Compressive strength measurement: Automatic compressive strength meter (Maekawa Seisakusho)

[Example 1]
Dimroth condenser, Teflon (registered trademark) stirring blade and stirrer with stirring seal, nitrogen introduction tube, and glass reaction vessel equipped with temperature sensor were charged with 109.2 parts of ion-exchanged water and stirred at 250 rpm. The mixture was heated to 70 ° C. while introducing nitrogen at 200 mL / min. Next, a mixed solution of methoxy polyethylene glycol monomethacrylic acid ester (average number of added moles of ethylene oxide 9): 100 parts, methacrylic acid: 20 parts, mercaptopropionic acid: 1.38 parts, and ion-exchanged water: 40 parts The mixture was added dropwise over 4 hours, and at the same time, a mixed solution of ammonium persulfate: 1.38 parts and ion-exchanged water: 28 parts was added dropwise over 5 hours. After completion of the dropwise addition, the aqueous solution of the polycarboxylic acid copolymer (1) was obtained by maintaining the polymerization reaction at 70 ° C. for 1 hour to complete the polymerization reaction. The obtained polycarboxylic acid copolymer (1) had a mass average molecular weight of 12500 and a pH of 1.8.
After adding 4.9 g (11 mol% with respect to COOH) of triisopropanolamine (TIPA) to the obtained polycarboxylic acid copolymer (1) and neutralizing a part of COOH with alkanolamine, 48% 13.1 g of NaOH aqueous solution (68 mol% with respect to COOH) was added to obtain an additive for cement (1) which is a mixed salt aqueous solution of an alkanolamine salt and an alkali metal salt of the polycarboxylic acid copolymer (1). .
Moreover, pH of the aqueous solution which adjusted the obtained additive for cement (1) so that the density | concentration of solid content might be 40 mass% was 6.4.
The results are shown in Tables 1 and 2.

[Example 2]
After adding 12.4 g of triisopropanolamine (28 mol% with respect to COOH) to 300 g of the polycarboxylic acid copolymer aqueous solution (1) obtained in Example 1, and neutralizing a part of COOH with alkanolamine Addition of 12.0 g of 48% NaOH aqueous solution (62 mol% with respect to COOH) and additive for cement which is a mixed salt aqueous solution of alkanolamine salt and alkali metal salt of polycarboxylic acid copolymer (1) (2) Got.
Moreover, pH of the aqueous solution which adjusted the obtained additive for cement (2) so that the density | concentration of solid content might be 40 mass% was 6.8.
The results are shown in Tables 1 and 2.

Example 3
After adding 33.9 g (54 mol% with respect to COOH) of triisopropanolamine to 300 g of the polycarboxylic acid copolymer aqueous solution (1) obtained in Example 1, and neutralizing a part of COOH with alkanolamine Addition of 7.0 g (36 mol% with respect to COOH) of 48% NaOH aqueous solution, and cement additive (3) which is a mixed salt aqueous solution of alkanolamine salt and alkali metal salt of polycarboxylic acid copolymer (1) Got.
Moreover, the pH of the aqueous solution which adjusted the obtained additive for cement (3) so that the density | concentration of solid content might be 40 mass% was 6.7.
The results are shown in Tables 1 and 2.

Example 4
Methoxypolyethylene glycol monomethacrylic acid ester (average number of added moles of ethylene oxide: 23): 110.2 parts, methacrylic acid: 9.8 parts, mercaptopropionic acid: 1.13 parts, and ion-exchanged water: 40 parts Was added dropwise over 4 hours, and at the same time, the same procedure as in Example 1 was performed except that a mixed solution of ammonium persulfate: 1.38 parts and ion-exchanged water: 28.3 parts was added dropwise over 5 hours. An aqueous solution of the acid copolymer (2) was obtained. The obtained polycarboxylic acid copolymer (2) had a mass average molecular weight of 13,300 and a pH of 2.0.
After adding 7.9 g (46 mol% with respect to COOH) of triisopropanolamine to the obtained polycarboxylic acid copolymer (2) and neutralizing a part of COOH with alkanolamine, a 48% NaOH aqueous solution was added. 2.0 g (27 mol% with respect to COOH) was added to obtain a cement additive (4) which is a mixed salt aqueous solution of an alkanolamine salt and an alkali metal salt of the polycarboxylic acid copolymer (2).
Moreover, pH of the aqueous solution which adjusted the obtained additive for cement (4) so that the density | concentration of solid content might be 40 mass% was 6.4.
The results are shown in Tables 1 and 2.

Example 5
Methoxypolyethylene glycol monomethacrylate (average number of moles of ethylene oxide added: 9): 100 parts, methacrylic acid: 20 parts, mercaptopropionic acid: 1.38 parts, and ion-exchanged water: 40 parts mixed solution over 4 hours At the same time, except that a mixed solution of ammonium persulfate: 0.35 parts and ion-exchanged water: 29.1 parts was added dropwise over 5 hours, the same procedure as in Example 1 was carried out. An aqueous solution of the union (3) was obtained. The obtained polycarboxylic acid copolymer (3) had a mass average molecular weight of 15,100 and a pH of 1.9.
After adding 4.9 g (11 mol% with respect to COOH) of triisopropanolamine to the obtained polycarboxylic acid copolymer (3) and neutralizing a part of COOH with alkanolamine, a 48% NaOH aqueous solution was added. 11.8 g (61 mol% with respect to COOH) was added to obtain a cement additive (5) which is a mixed salt aqueous solution of an alkanolamine salt and an alkali metal salt of the polycarboxylic acid copolymer (3).
Moreover, pH of the aqueous solution which adjusted the obtained additive for cement (5) so that the density | concentration of solid content might be 40 mass% was 6.4.
The results are shown in Tables 1 and 2.

Example 6
5.7 g (14 mol% with respect to COOH) of hydroxyethyl diisopropanolamine (EDIPA) was added to 300 g of the polycarboxylic acid copolymer aqueous solution (1) obtained in Example 1, and a part of COOH was added to alkanolamine. After neutralization with 14.7 g of a 48% NaOH aqueous solution (76 mol% with respect to COOH), the cement is a mixed salt aqueous solution of an alkanolamine salt and an alkali metal salt of the polycarboxylic acid copolymer (1). Additive (6) was obtained.

Moreover, pH of the aqueous solution which adjusted the obtained additive for cement (6) so that the density | concentration of solid content might be 40 mass% was 6.8.
The results are shown in Tables 1 and 2.

Example 7
19.7 g (57 mol% with respect to COOH) of triethanolamine (TEA) was added to 300 g of the polycarboxylic acid copolymer aqueous solution (1) obtained in Example 1, and a part of COOH was added with alkanolamine. After the addition, 6.4 g of a 48% NaOH aqueous solution (76 mol% with respect to COOH) is added, and the additive for cement is a mixed salt aqueous solution of an alkanolamine salt and an alkali metal salt of the polycarboxylic acid copolymer (1) (7) was obtained.
Moreover, the pH of the aqueous solution which adjusted the obtained additive for cement (7) so that the density | concentration of solid content might be 40 mass% was 6.8.
The results are shown in Tables 1 and 2.

Example 8
38.6 g (57 mol% with respect to COOH) of tetrakis (2-hydroxypropyl) ethylenediamine (THETA) was added to 300 g of the aqueous polycarboxylic acid copolymer solution (1) obtained in Example 1, and a part of COOH After being neutralized with alkanolamine, 5.0 g of a 48% NaOH aqueous solution (26 mol% with respect to COOH) was added, and a mixed salt aqueous solution of the alkanolamine salt and alkali metal salt of polycarboxylic acid copolymer (1) was added. A cement additive (8) was obtained.
Moreover, the pH of the aqueous solution which adjusted the obtained additive for cement (8) so that the density | concentration of solid content might be 40 mass% was 6.7.
The results are shown in Tables 1 and 2.

Example 9
Methoxypolyethylene glycol monomethacrylate (average number of moles of ethylene oxide added: 9): 100 parts, acrylic acid: 20 parts, mercaptopropionic acid: 1.38 parts, and ion-exchanged water: 40 parts mixed solution over 4 hours At the same time, except that a mixed solution of ammonium persulfate: 0.35 parts and ion-exchanged water: 29.1 parts was added dropwise over 5 hours, the same procedure as in Example 1 was carried out. An aqueous solution of the combined (4) was obtained. The obtained polycarboxylic acid copolymer (4) had a weight average molecular weight of 18,200 and a pH of 1.7.
After adding 6.3 g (12 mol% with respect to COOH) of triisopropanolamine to the obtained polycarboxylic acid copolymer (4) and neutralizing a part of COOH with alkanolamine, a 48% NaOH aqueous solution was added. 18.0 g (78 mol% with respect to COOH) was added to obtain a cement additive (9) which is a mixed salt aqueous solution of an alkanolamine salt and an alkali metal salt of the polycarboxylic acid copolymer (4).
Moreover, the pH of the aqueous solution which adjusted the obtained additive (9) for cement so that the density | concentration of solid content might be 40 mass% was 6.7.
The results are shown in Tables 1 and 2.

Example 10
After adding 4.9 g of triisopropanolamine (11 mol% with respect to COOH) to 300 g of the polycarboxylic acid copolymer aqueous solution (1) obtained in Example 1, and neutralizing a part of COOH with alkanolamine 16.6 g of a 48% NaOH aqueous solution (86 mol% with respect to COOH), and an additive for cement which is a mixed salt aqueous solution of an alkanolamine salt and an alkali metal salt of the polycarboxylic acid copolymer (1) (10) Got.
Moreover, pH of the aqueous solution which adjusted the obtained additive for cement (10) so that the density | concentration of solid content might be 40 mass% was 7.0.
The results are shown in Tables 1 and 2.

Example 11
After adding 4.9 g of triisopropanolamine (11 mol% with respect to COOH) to 300 g of the polycarboxylic acid copolymer aqueous solution (1) obtained in Example 1, and neutralizing a part of COOH with alkanolamine , 48% NaOH aqueous solution 5.8g (30mol% with respect to COOH), additive for cement (11) which is a mixed salt aqueous solution of alkanolamine salt and alkali metal salt of polycarboxylic acid copolymer (1) Got.
Moreover, pH of the aqueous solution which adjusted the obtained additive for cement (11) so that the density | concentration of solid content might be 40 mass% was 5.6.
The results are shown in Tables 1 and 2.

Example 12
4.9 g (11 mol% with respect to COOH) of triisopropanolamine was added to 300 g of the polycarboxylic acid copolymer aqueous solution (1) obtained in Example 1, and a part of COOH was neutralized with alkanolamine. Cement additive (12), which is a mixed salt aqueous solution of alkanolamine salt and alkali metal salt of polycarboxylic acid copolymer (1), was obtained.
Moreover, pH of the aqueous solution which adjusted the obtained additive for cement (12) so that the density | concentration of solid content might be 40 mass% was 4.4.
The results are shown in Tables 1 and 2.

[Comparative Example 1]
14.7 g of a 48% NaOH aqueous solution (30 mol% with respect to COOH) was added to 300 g of the polycarboxylic acid copolymer aqueous solution (1) obtained in Example 1, and the polycarboxylic acid copolymer aqueous solution (1) A cement additive (C1), which is an aqueous solution of an alkali metal salt, was obtained.
Moreover, pH of the aqueous solution which adjusted the additive for cement (C1) obtained so that the density | concentration of solid content might be 40 mass% was 6.4.
The results are shown in Tables 1 and 2.

[Comparative Example 2]
To 300 g of the polycarboxylic acid copolymer aqueous solution (2) obtained in Example 4, 5.7 g of a 48% NaOH aqueous solution (30 mol% with respect to COOH) was added, and the polycarboxylic acid copolymer (1) A cement additive (C2), which is an aqueous solution of an alkali metal salt, was obtained.
Moreover, pH of the aqueous solution which adjusted the obtained additive for cement (C2) so that the density | concentration of solid content might be 40 mass% was 6.5.
The results are shown in Tables 1 and 2.

[Comparative Example 3]
After adding 31.4 g of triisopropanolamine (71 mol% with respect to COOH) to 300 g of the polycarboxylic acid copolymer aqueous solution (1) obtained in Example 1, and neutralizing a part of COOH with alkanolamine And an additive for cement (C3) which is a mixed salt aqueous solution of alkanolamine salt and alkali metal salt of polycarboxylic acid copolymer (1) by adding 3.7 g (19 mol% with respect to COOH) of 48% NaOH aqueous solution. Got.
Moreover, the pH of the aqueous solution which adjusted the obtained additive for cement (C3) so that the density | concentration of solid content might be 40 mass% was 6.7.
The results are shown in Tables 1 and 2.

[Comparative Example 4]
1.3 g of triisopropanolamine (3.0 mol% with respect to COOH) was added to 300 g of the aqueous polycarboxylic acid copolymer solution (1) obtained in Example 1, and a part of COOH was neutralized with alkanolamine. After that, 16.8 g of a 48% NaOH aqueous solution (87 mol% with respect to COOH) was added, and an additive for cement which is a mixed salt aqueous solution of an alkanolamine salt and an alkali metal salt of the polycarboxylic acid copolymer (1) ( C4) was obtained.
Moreover, the pH of the aqueous solution which adjusted the obtained additive for cement (C4) so that the density | concentration of solid content might be 40 mass% was 6.8.
The results are shown in Tables 1 and 2.

  From Tables 1 and 2, it can be seen that the cement additive of the present invention can suppress the by-product of bow glass and can reduce the amount used to achieve the same fluidity when used as a cement composition. In Comparative Examples 1, 2, and 4, a large amount of by-product of bow glass was observed, and in Comparative Example 3, the amount of cement additive used to achieve the same level of flow value as in the Examples was increased.

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

Claims (3)

Derived from the structural unit (I) derived from the unsaturated polyalkylene glycol monomer (a) represented by the general formula (1) and the unsaturated carboxylic acid monomer (b) represented by the general formula (2) A polycarboxylic acid copolymer having the structural unit (II):
10 mol% to 65 mol% in the total amount of —COOM group and —COOX group in the general formula (2) is an alkanolamine salt,
0 mol% to 90 mol% of the total amount of -COOM group and -COOX group in the general formula (2) is an alkali metal salt or an alkaline earth metal salt,
Additive for cement.

(In General Formula (1), R ¹ and R ² are the same or different and each represents a hydrogen atom or a methyl group; R ³ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms; Represents an oxyalkylene group having 2 to 18 carbon atoms, n represents the average number of added moles of the oxyalkylene group represented by AO, n is an integer of 1 to 90, and x is an integer of 0 to 2 .)

(In general formula (2), R ^{4 to} R ⁶ are the same or different and each represents a hydrogen atom, a methyl group, or — (CH ₂ ) _z COOM group, and — (CH ₂ ) _z COOM group represents a —COOX group. Or other — (CH ₂ ) _z COOM group may form an anhydride, z is an integer of 0 to 2, M is a hydrogen atom, alkali metal, alkaline earth metal, ammonium group, organic An ammonium group or an organic amine group is represented, and X represents a hydrogen atom, a methyl group, an ethyl group, an alkali metal, an alkaline earth metal, an ammonium group, an organic ammonium group, or an organic amine group.)   The total of the alkanolamine salt, the alkali metal salt, and the alkaline earth metal salt in the total amount of -COOM group and -COOX group in the general formula (2) is 10 mol% to 100 mol%. The additive for cement according to 1. A cement composition comprising the cement additive according to claim 1 or 2.