JP2005119918A - Cement additive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cement additive which gives a cement composition being high in fluidity, kneadability, and slump retention and therefore excellent in workability even when the amount of water added to the cement composition is small, is excellent in economy because of its effectiveness in a smaller amount, and is excellent in stability in an aqueous solution. <P>SOLUTION: It has been found out that the above problem can be solved by introducing polyalkylene glycol groups as dispersion groups into a polymer not through ester linkages but through amide linkages or imide linkages. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cement additive. More specifically, the present invention relates to a cement additive having excellent fluidity of cement paste, mortar, and concrete, and having excellent mortar kneadability and slump retention. Moreover, since the cement additive has high hydrolysis resistance, it has excellent long-term storage stability.

Since the cement composition gives a cured product excellent in strength and durability, it is widely used in applications such as building outer wall materials and building structures. A cement additive is usually added to such a cement composition in order to enhance air entrainment and fluidity. Since the early deterioration of a concrete structure became a social problem in 1981, the cement composition has been added. Recognizing the importance of cement additives that greatly affect the quality and performance of products, technological innovation of cement additives to replace conventional naphthalene cement additives has been actively conducted. In particular, polycarboxylic acid-based cement dispersants have many proposals because they exhibit higher water reduction performance than conventional naphthalene-based cement dispersants. For example, JP-A-6-256054 and JP-A-7-2126026 disclose cement dispersants using a copolymer of an alkyl vinyl ether and an alkoxy polyalkylene glycol maleic acid half ester. However, there is room for improvement in achieving excellent fluidity and kneading performance of mortar even in the polycarboxylic acids disclosed in JP-A-6-256054 and JP-A-7-216026.
Japanese Patent Laid-Open No. 2000-247707 discloses a cement additive obtained by half-esterifying an acid anhydride portion of a copolymer of alkyl vinyl ether and maleic anhydride with an alkoxy polyalkylene glycol. Because the alkylene glycol moiety is linked to the main chain of the polymer via an ester bond, it hydrolyzes in a strong alkaline cement solution environment, causing slump loss and gradually causing hydrolysis in the aqueous solution. There was also room for improvement in storage stability as a product.

JP-A-6-256054 JP 7-216062 A JP 2000-247707 A

  The present invention has been made in view of the above situation, and while reducing the amount of water added to the cement composition, the fluidity, kneadability and slump retention are high, the workability is excellent, and the addition amount is also high. An object of the present invention is to provide a cement additive which is small and excellent in economic efficiency and excellent in storage stability in an aqueous solution.

The present inventors have found that the above problem can be solved by introducing a polyalkylene glycol group as a dispersing group through an amide bond or an imide bond instead of an ester bond. That is, this invention is a cement additive shown to following <1>-<2>.
<1> As a repeating unit, the following general formula (1)

(However, in the formula, R ¹ O represents one or a mixture of two or more oxyalkylene groups having 2 to 18 carbon atoms, and in the case of two or more types, R ¹ O is added in a random form even if it is added in a block form. R ² represents a hydrocarbon group having 1 to 30 carbon atoms, M ¹ represents hydrogen, a monovalent metal, a divalent metal, ammonium, an organic ammonium group, and n represents an average addition mole of an oxyalkylene group. And represents a number of 1 to 300.) and / or the following general formula (2)

(However, in the formula, R ¹ O represents one or a mixture of two or more oxyalkylene groups having 2 to 18 carbon atoms, and in the case of two or more types, R ¹ O is added in a random form even if it is added in a block form. R ² represents a hydrocarbon group having 1 to 30 carbon atoms, n represents an average added mole number of an oxyalkylene group, and represents a number of 1 to 300). Including
And the following general formula (3)

(In the formula, R ³ represents a hydrocarbon group having 1 to 30 carbon atoms.)
It is achieved by a cement additive comprising a copolymer (I) containing a repeating unit (C) represented by
<2> As a repeating unit, the following general formula (4)

The repeating unit (D) represented by the following general formula (3)

(In the formula, R ¹¹ represents a hydrocarbon group having 1 to 30 carbon atoms.)
In the acid anhydride part of the copolymer (II) containing the repeating unit (C) represented by the following general formula (5)

(However, in the formula, R ¹ O represents one or a mixture of two or more oxyalkylene groups having 2 to 18 carbon atoms, and in the case of two or more types, R ¹ O is added in a random form even if it is added in a block form. R ² represents a hydrocarbon group having 1 to 30 carbon atoms, and n represents the average number of added moles of an oxyalkylene group and represents a number of 1 to 300.)
It is also achieved by a cement additive containing a copolymer (III) obtained by amidation or imidization with one or more of the polyalkylene glycol amines (a) represented by

  The cement additive of the present invention has excellent fluidity of cement paste, mortar, and concrete, and has excellent mortar kneadability and slump retention. In addition, since it has high hydrolysis resistance, it has excellent long-term storage stability.

The cement additive of the present invention comprises a cement additive containing either of the copolymers (I) and (III) as an essential component.

Copolymers (I) and (III) are represented by the following general formula (5) in the acid anhydride portion of copolymer (II).

It can obtain by making polyalkylene glycol amine (a) shown by these react.

As polyalkylene glycol amine (a), C1-C30, such as methanol, ethanol, 2-propanol, 1-butanol, octanol, 2-ethyl-1-hexanol, nonyl alcohol, lauryl alcohol, cetyl alcohol, stearyl alcohol, etc. Aliphatic alcohols of 3 to 30 carbon atoms such as cyclohexanol; phenol, phenylmethanol (benzyl alcohol), methylphenol (cresol), p-ethylphenol, dimethylphenol (xylenol), p- Alcohols having a benzene ring such as t-butylphenol, nonylphenol, dodecylphenol, phenylphenol, naphthol; 3 to 3 carbon atoms such as allyl alcohol, methallyl alcohol, crotyl alcohol A compound obtained by converting a terminal hydroxyl group of an alkoxypolyalkylene glycol obtained by adding one or more of alkylene oxides having 2 to 18 carbon atoms to any of the alcohols having an alkenyl group into a primary amino group, etc. Can be used.

  Specific examples include JEFFAMINEs manufactured by Huntsman and those obtained by converting terminal hydroxyl groups of the alkoxypolyalkylene glycols shown below to amino groups, and one or more of these may be used. it can.

  The alkoxypolyalkylene glycols are not particularly limited, and examples thereof include the following. Methoxy polyethylene glycol, methoxy polyethylene glycol (poly) propylene glycol, methoxy polyethylene glycol (poly) butylene glycol, methoxy polyethylene glycol (poly) propylene glycol (poly) butylene glycol, methoxy polypropylene glycol, methoxy polypropylene glycol (poly) ethylene glycol, methoxy Polybutylene glycol, methoxypolybutylene glycol (poly) ethylene glycol, ethoxy polyethylene glycol, ethoxy polyethylene glycol (poly) propylene glycol, ethoxy polyethylene glycol (poly) butylene glycol, ethoxy polyethylene glycol (poly) propylene glycol (poly) butylene glycol, Ethoxypoly Lopylene glycol, ethoxy polypropylene glycol (poly) ethylene glycol, ethoxy polybutylene glycol, ethoxy polybutylene glycol (poly) ethylene glycol, propoxy polyethylene glycol, propoxy polyethylene glycol (poly) propylene glycol, propoxy polyethylene glycol (poly) butylene glycol, propoxy Polyethylene glycol (poly) propylene glycol (poly) butylene glycol, propoxypolypropylene glycol, propoxypolypropylene glycol (poly) ethylene glycol, propoxypolybutylene glycol, propoxypolybutylene glycol (poly) ethylene glycol.

  Butoxypolyethylene glycol, butoxypolyethylene glycol (poly) propylene glycol, butoxypolyethylene glycol (poly) butylene glycol, butoxypolyethylene glycol (poly) propylene glycol (poly) butylene glycol, butoxypolypropylene glycol, butoxypolypropylene glycol (poly) ethylene glycol, butoxy Polybutylene glycol, butoxypolybutylene glycol (poly) ethylene glycol, pentoxypolyethylene glycol, pentoxypolyethylene glycol (poly) propylene glycol, pentoxypolyethylene glycol (poly) butylene glycol, pentoxypolyethylene glycol (poly) propylene glycol (poly ) Butylene glycol, pe Toxipolypropylene glycol, pentoxypolypropylene glycol (poly) ethylene glycol, pentoxypolybutylene glycol, pentoxypolybutylene glycol (poly) ethylene glycol, hexoxypolyethylene glycol, hexoxypolyethyleneglycol (poly) propyleneglycol, hexoxypolyethyleneglycol (Poly) butylene glycol, hexoxypolyethylene glycol (poly) propylene glycol (poly) butylene glycol, hexoxypolypropylene glycol, hexoxypolypropylene glycol (poly) ethylene glycol, hexoxypolybutylene glycol, hexoxypolybutylene glycol (poly) Ethylene glycol, octoxypolyethylene glycol, oct Si polyethylene glycol (poly) propylene glycol, octoxy polyethylene glycol (poly) butylene glycol, octoxy polyethylene glycol (poly) propylene glycol (poly) butylene glycol, octoxy polypropylene glycol, octoxy polypropylene glycol (poly) ethylene glycol, oct Xypolybutylene glycol, octoxypolybutylene glycol (poly) ethylene glycol.

  Decanoxy polyethylene glycol, decanoxy polyethylene glycol (poly) propylene glycol, decanoxy polyethylene glycol (poly) butylene glycol, decanoxy polyethylene glycol (poly) propylene glycol (poly) butylene glycol, decanoxy polypropylene glycol, Decanoxy polypropylene glycol (poly) ethylene glycol, decanoxy polybutylene glycol, decanoxy polybutylene glycol (poly) ethylene glycol, dodecanoxy polyethylene glycol, dodecanoxy polyethylene glycol (poly) propylene glycol, dodecanoxy Polyethylene glycol (poly) butylene glycol, dodecanoxy polyethylene glycol (poly) propylene glycol (poly Butylene glycol, dodecanoxy polypropylene glycol, dodecanoxy polypropylene glycol (poly) ethylene glycol, dodecanoxy polybutylene glycol, dodecanoxy polybutylene glycol (poly) ethylene glycol, hexadecanoxy polyethylene glycol, hexadecano Xylethylene glycol (poly) propylene glycol, hexadecanoxy polyethylene glycol (poly) butylene glycol, hexadecanoxy polyethylene glycol (poly) propylene glycol (poly) butylene glycol, hexadecanoxy polypropylene glycol, hexadecanoxy polypropylene Glycol (poly) ethylene glycol, hexadecanoxy polybutylene glycol, hexadecanoxy polybutylene Glycol (poly) ethylene glycol, octadecanoxy polyethylene glycol, octadecanoxy polyethylene glycol (poly) propylene glycol, octadecanoxy polyethylene glycol (poly) butylene glycol, octadecanoxy polyethylene glycol (poly) propylene glycol ( Poly) butylene glycol, octadecanoxy polypropylene glycol, octadecanoxy polypropylene glycol (poly) ethylene glycol, octadecanoxy polybutylene glycol, octadecanoxy polybutylene glycol (poly) ethylene glycol.

  Phenoxy polyethylene glycol, phenoxy polyethylene glycol (poly) propylene glycol, phenoxy polyethylene glycol (poly) butylene glycol, phenoxy polyethylene glycol (poly) propylene glycol (poly) butylene glycol, phenoxy polypropylene glycol, phenoxy polypropylene glycol (poly) ethylene glycol, phenoxy Polybutylene glycol, phenoxypolybutylene glycol (poly) ethylene glycol, phenylmethoxypolyethylene glycol, phenylmethoxypolyethyleneglycol (poly) propylene glycol, phenylmethoxypolyethyleneglycol (poly) butyleneglycol, phenylmethoxypolyethyleneglycol (poly) propylene Recall (poly) butylene glycol, phenylmethoxypolypropylene glycol, phenylmethoxypolypropylene glycol (poly) ethylene glycol, phenylmethoxypolybutylene glycol, phenylmethoxypolybutylene glycol (poly) ethylene glycol, methylphenoxypolyethylene glycol, methylphenoxypolyethyleneglycol (poly ) Propylene glycol, methylphenoxypolyethylene glycol (poly) butylene glycol, methylphenoxypolyethylene glycol (poly) propylene glycol (poly) butylene glycol, methylphenoxypolypropylene glycol, methylphenoxypolypropylene glycol (poly) ethylene glycol, methylphenoxypolybutyleneglycol , Methylphenoxypolybutylene glycol (poly) ethylene glycol, p-ethylphenoxypolyethylene glycol, p-ethylphenoxypolyethylene glycol (poly) propylene glycol, p-ethylphenoxypolyethylene glycol (poly) butylene glycol, p-ethylphenoxypolyethylene glycol (Poly) propylene glycol (poly) butylene glycol, p-ethylphenoxypolypropylene glycol, p-ethylphenoxypolypropylene glycol (poly) ethylene glycol, p-ethylphenoxypolybutylene glycol, p-ethylphenoxypolybutylene glycol (poly) ethylene glycol .

  Dimethylphenoxy polyethylene glycol, dimethyl phenoxy polyethylene glycol (poly) propylene glycol, dimethyl phenoxy polyethylene glycol (poly) butylene glycol, dimethyl phenoxy polyethylene glycol (poly) propylene glycol (poly) butylene glycol, dimethyl phenoxy polypropylene glycol, dimethyl phenoxy polypropylene glycol ( Poly) ethylene glycol, dimethylphenoxypolybutylene glycol, dimethylphenoxypolybutylene glycol (poly) ethylene glycol, pt-butylphenoxypolyethylene glycol, pt-butylphenoxypolyethylene glycol (poly) propylene glycol, pt-butyl Phenoxy polyethylene glycol (Poly) butylene glycol, pt-butylphenoxypolyethylene glycol (poly) propylene glycol (poly) butylene glycol, pt-butylphenoxypolypropylene glycol, pt-butylphenoxypolypropylene glycol (poly) ethylene glycol, p -T-butylphenoxypolybutylene glycol, pt-butylphenoxypolybutylene glycol (poly) ethylene glycol, nonylphenoxypolyethylene glycol, nonylphenoxypolyethylene glycol (poly) propylene glycol, nonylphenoxypolyethylene glycol (poly) butylene glycol, nonyl Phenoxypolyethylene glycol (poly) propylene glycol (poly) butylene glycol, nonylphenoxy Ripropylene glycol, nonylphenoxypolypropylene glycol (poly) ethylene glycol, nonylphenoxypolybutylene glycol, nonylphenoxypolybutylene glycol (poly) ethylene glycol, dodecylphenoxypolyethylene glycol, dodecylphenoxypolyethylene glycol (poly) propylene glycol, dodecylphenoxypolyethylene glycol (Poly) butylene glycol, dodecylphenoxypolyethylene glycol (poly) propylene glycol (poly) butylene glycol, dodecylphenoxypolypropylene glycol, dodecylphenoxypolypropylene glycol (poly) ethylene glycol, dodecylphenoxypolybutylene glycol, dodecylphenoxypolybutylene glycol (Poly) ethylene glycol.

Phenylphenoxypolyethylene glycol, phenylphenoxypolyethyleneglycol (poly) propyleneglycol, phenylphenoxypolyethyleneglycol (poly) butyleneglycol, phenylphenoxypolyethyleneglycol (poly) propyleneglycol (poly) butyleneglycol, phenylphenoxypolypropyleneglycol, phenylphenoxypolypropyleneglycol ( Poly) ethylene glycol, phenylphenoxypolybutylene glycol, phenylphenoxypolybutylene glycol (poly) ethylene glycol, naphthoxypolyethylene glycol, naphthoxypolyethylene glycol (poly) propylene glycol, naphthoxypolyethylene glycol (poly) butylene glycol, naphthoxy Liethylene glycol (poly) propylene glycol (poly) butylene glycol, naphthoxypolypropylene glycol, naphthoxypolypropylene glycol (poly) ethylene glycol, naphthoxypolybutylene glycol, naphthoxypolybutylene glycol (poly) ethylene glycol, methallyloxypolyethylene glycol , Methallyloxypolyethylene glycol (poly) propylene glycol, methallyloxypolyethylene glycol (poly) butylene glycol, methallyloxypolyethylene glycol (poly) propylene glycol (poly) butylene glycol, methallyloxypolypropylene glycol, methallyloxypolypropylene glycol (Poly) ethylene glycol, methallyloxypolybutylene glycol , Methallyloxypolybutylene glycol (poly) ethylene glycol, allyloxy polyethylene glycol, allyloxy polyethylene glycol (poly) propylene glycol, allyloxy polyethylene glycol (poly) butylene glycol, allyloxy polyethylene glycol (poly) propylene glycol ( Poly) butylene glycol, allyloxypolypropylene glycol, allyloxypolypropylene glycol (poly) ethylene glycol, allyloxypolybutylene glycol, allyloxypolybutylene glycol (poly) ethylene glycol.

As the oxyalkylene groups R ¹ O and R ³ O constituting the alkoxypolyalkylene glycol chain, one or more of any alkylene oxide having 2 to 18 carbon atoms can be used. When two or more types of alkylene oxide are used, any of random addition, block addition, and alternate addition can be used.

  The average addition mole number n of the oxyalkylene group is a number of 1 to 300, but in order to improve the excellent dispersibility and mortar kneadability, the range of 10 to 280 is preferable, more preferably 25 to 250, Preferably it is 40-220, More preferably, it is the range of 110-200. When the average added mole number of the oxyalkylene group is 0 or 300 or more, the cement dispersibility is deteriorated and it is difficult to obtain a cement composition having high fluidity. Further, it is preferable that 50 mol% or more of oxyalkylene groups are oxyethylene groups in order to obtain excellent dispersibility and mortar kneadability. The content of oxyethylene groups is preferably 50 to 100 mol%, more preferably 60 to 100 mol%, and still more preferably 80 to 100 mol%. The reason why 50 mol% or more of the oxyalkylene groups is preferably an oxyethylene group is that when the oxyethylene group is less than 50 mol%, the water solubility of the copolymer becomes insufficient. When the oxyethylene group is less than 100 mol%, it is preferable to use other oxyalkylene groups having a small number of carbon atoms such as oxypropylene groups and oxybutylene groups from the viewpoint of water solubility.

From the viewpoint of improving cement dispersion performance and mortar kneading performance, the terminal alkyl group R ² of the alkoxypolyalkylene glycol amine (a) is preferably a hydrocarbon group having 1 to 3 carbon atoms such as a methyl group, an ethyl group, or a propyl group. From the viewpoint of excellent dispersion performance and material separation reduction performance, hydrocarbon groups having 4 to 8 carbon atoms such as n-butyl group, i-propyl group, pentyl group and hexyl group are preferred. From the viewpoint of excellent separation reduction performance, hydrocarbon groups having 9 to 18 carbon atoms such as lauryl group and stearyl group are preferable.

  The copolymer (II) can be obtained by a known polymerization method from a monomer mixture containing maleic anhydride and a monomer that gives the repeating unit (C). The monomer for forming the repeating unit (C) is not particularly limited. For example, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, isopropyl vinyl ether, isobutyl vinyl ether, 1,2-dimethoxyethylene, phenyl vinyl ether, benzyl Examples thereof include alkyl vinyl ethers such as vinyl ether. These may be used alone or in combination of two or more. In particular, it is preferable to use a vinyl ether having relatively high hydrophilicity such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, and butyl vinyl ether from the viewpoint of water solubility of the copolymer.

  It is possible to introduce a copolymerizable monomer (b) other than maleic anhydride and the monomer giving the repeating unit (C). It does not specifically limit as a monomer which can be copolymerized, For example, the following etc. are mentioned, These 1 type (s) or 2 or more types can be used. Styrene; alkyl-substituted styrenes such as o-methyl styrene, m-methyl styrene, p-methyl styrene, α-methyl styrene, ethyl styrene, propyl styrene, and derivatives thereof; styrene sulfonic acid; ethylene; propylene, butylene, isobutylene, Α-olefins such as 1-pentene, 1-hexene, 1-decene and 1-octadecene, and linear or branched olefins; cyclic olefins such as cyclopentene and cyclohexene; butadiene, isoprene, 1,3- Dienes such as pentadiene and 2,4-hexadiene; vinyl esters such as vinyl acetate, vinyl propionate and vinyl butanoate; allyl alcohol, methallyl alcohol, 3-methyl-3-buten-1-ol, 3-methyl 2-buten-1-ol, 2-methyl-3 An unsaturated alcohol such as buten-2-ol; an unsaturated alcohol adduct obtained by etherifying a hydroxyl group of the unsaturated alcohol with a hydrocarbon group having 1 to 30 carbon atoms; an alkylene oxide 1 having 2 to 30 carbon atoms in vinyl alcohol; Addition of ~ 300 mol of vinyl alcohol (poly) alkylene oxide adduct; Addition of vinyl alcohol (poly) alkylene oxide obtained by etherifying the terminal hydroxyl group of the above vinyl alcohol (poly) alkylene oxide adduct with a hydrocarbon group having 1 to 30 carbon atoms Product: Acrylonitrile, methacrylonitrile.

  Esterified product of alkoxy polyalkylene glycol and (meth) acrylic acid; unsaturated alcohol (poly) alkylene oxide adduct obtained by adding 1 to 300 moles of alkylene oxide having 2 to 30 carbon atoms to the above-mentioned unsaturated alcohol; Unsaturated alcohol (poly) alkylene oxide adducts obtained by etherifying terminal hydroxyl groups of saturated alcohol (poly) alkylene oxide adducts with hydrocarbon groups having 1 to 30 carbon atoms; maleic acid, fumaric acid, itaconic acid, citraconic acid and the like Monovalent metal salts, divalent metal salts, unsaturated dicarboxylic acids such as ammonium salts and organic amine salts, or their anhydrides; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid and carbon Half esters and diesters with several to 30 alcohols; Half amides and diamides of sum dicarboxylic acids and amines having 1 to 30 carbon atoms; alkyl polyalkylene glycols obtained by adding 1 to 500 moles of oxyalkylene having 2 to 18 carbon atoms to the above alcohols and amines having 1 to 30 carbon atoms; Half esters and diesters with unsaturated dicarboxylic acids such as fumaric acid, itaconic acid and citraconic acid; the above unsaturated dicarboxylic acids and glycols having 2 to 18 carbon atoms or polyalkylene glycols having 2 to 500 addition moles of these glycols; A half amide of maleamic acid and a glycol having 2 to 18 carbon atoms or a polyalkylene glycol having an addition mole number of these glycols of 2 to 500; (meth) acrylic acid and monovalent metal salts thereof, ammonium Salts and organic amine salts; methoxypolyethylene Glycol, ethoxy polyethylene glycol, propoxy polyethylene glycol, ester such methoxypolyethylene glycol polypropylene glycol, ethoxy polyethylene glycol polypropylene glycol, and alkoxy polyalkylene glycol and (meth) acrylic acid such as propoxy polyethylene glycol polypropylene glycol.

  Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth) Esters of (meth) acrylic acid and alcohols having 1 to 30 carbon atoms such as hydroxypropyl acrylate, hydroxybutyl (meth) acrylate, methyl crotonate, glycidyl (meth) acrylate; triethylene glycol di (meta ) Acrylates, (poly) ethylene glycol di (meth) acrylates, polypropylene glycol di (meth) acrylates, (poly) ethylene glycol (poly) propylene glycol di (meth) acrylates and other (poly) alkylene glycol di (meth) acrylates Hexanehexane Bifunctional or trifunctional (meth) acrylates such as (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane di (meth) acrylate; (poly) such as triethylene glycol dimaleate and polyethylene glycol dimaleate Alkylene glycol dimaleates.

Vinyl sulfonate, (meth) allyl sulfonate, 2- (meth) acryloxyethyl sulfonate, 3- (meth) acryloxypropyl sulfonate, 3- (meth) acryloxy-2-hydroxypropyl sulfonate, 3- (meth) acryloxy-2 -Hydroxypropylsulfophenyl ether, 3- (meth) acryloxy-2-hydroxypropyloxysulfobenzoate, 4- (meth) acryloxybutylsulfonate, (meth) acrylamidomethylsulfonic acid, (meth) acrylamidoethylsulfonic acid, 2- Unsaturated sulfonic acids such as methylpropanesulfonic acid (meth) acrylamide and the like, and their monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts; 1,4-butanediol mono (meth) acrylate, 1, -Alkanediol mono (meth) acrylates such as pentanediol mono (meth) acrylate and 1,6-hexanediol mono (meth) acrylate; unsaturated monocarboxylic acids such as methyl (meth) acrylamide and carbon atoms of 1 to 30 Amides with two amines; unsaturated amides such as (meth) acrylamide, (meth) acrylalkylamide, N-methylol (meth) acrylamide, N, N-dimethyl (meth) acrylamide and the like.

  Unsaturation such as aminoethyl (meth) acrylate, methylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, dibutylaminoethyl (meth) acrylate, vinylpyridine, etc. Amines; cyanurates such as triallyl cyanurate; allyls such as (meth) allyl alcohol and glycidyl (meth) allyl ether; unsaturated amino compounds such as dimethylaminoethyl (meth) acrylate; polydimethylsiloxanepropylaminomalein Amic acid, polydimethylsiloxane aminopropylaminomaleamic acid, polydimethylsiloxane-bis- (propylaminomaleamic acid), polydimethylsiloxane-bis- (dipropylaminomaleamic acid), polydimethyl Siloxane- (1-propyl-3-acrylate), polydimethylsiloxane- (1-propyl-3-methacrylate), polydimethylsiloxane-bis- (1-propyl-3-acrylate), polydimethylsiloxane-bis- ( Siloxane derivatives such as 1-propyl-3-methacrylate).

  Unsaturated nitriles such as α-chloroacrylonitrile; divinyl aromatics such as divinylbenzene; allyl monomers such as allyl acetic acid, allylbenzene, 2-allylphenol, 3-allylcyclopentane; allyl ether, allyl lactone, etc. Allyl alcohol derivative monomers; vinyl esters such as isopropenyl acetate; vinyl aromatics.

  N-vinylsuccinimide, N-vinylcarbazole, 1-vinylimidazole, N-vinylcaprolactam, N-vinyloxazolidone, N-vinylpyrrolidone, N-vinylformamide, N-methyl-N-vinylformamide, N-vinylacetamide, N-vinyl compounds such as N-methyl-N-vinylacetamide are exemplified.

  The production method of the copolymer (I) from the copolymer (II) can be a known amidation or imidation method, and is not particularly limited. For example, using a catalyst in a solvent, Reaction conditions such as reaction time and reaction temperature can be set appropriately. By setting these reaction conditions, amidation can be prioritized or imidation can be prioritized.

  The solvent is not particularly limited. For example, benzene derivatives such as benzene, toluene and ethylbenzene; organic esters such as ethyl acetate and isopropyl acetate; ketones such as methyl ethyl ketone and methyl isobutyl ketone; tetrahydrofuran, 1,3-dioxane and the like And cyclic ethers. In addition, polyoxyalkylene glycol amines used for amidation and imidization can be used as a solvent. Furthermore, the solvent used as the polymerization solvent can be used as it is as the solvent in the amidation / imidization reaction. In this case, polymerization and amidation / imidization can be carried out by continuous processes. These may be used alone or in combination of two or more. The amidation / imidization catalyst is not particularly limited, and examples thereof include tertiary amines such as triethylamine, triethanolamine, and pyridine. These may be used alone or in combination of two or more.

  Further, after the amidation / imidation reaction, a part or all of the carboxyl groups in the polycarboxylic acid polymer may be converted into a salt form, if necessary. Further, in the case of amidation / imidation reaction of polyoxyalkylene glycol amine (a) less than equimolar with respect to the repeating unit (D) in the copolymer (II), methanol, ethanol, propanol, butanol Alternatively, esterification with an alkyl alcohol such as hexanol, lauryl alcohol, stearyl alcohol, phenol or benzyl alcohol, or amidation with an alkylamine such as diethylamine or diisopropylamine may be performed. Further, the unreacted acid anhydride portion may be simply hydrolyzed with an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution.

  The copolymer (I) is a monomer that provides the repeating unit (A) represented by the general formula (1) and / or a monomer that provides the repeating unit (B) represented by the general formula (2). And a monomer giving the repeating unit (C) represented by the general formula (3).

Examples of the monomer that gives the repeating unit (A) include amidated products of the polyoxyalkylene glycol amine represented by the general formula (5), maleic acid, and maleic anhydride. More than seeds can be used. When two or more types of monomers are used, an amidated product of two or more types of polyoxyalkylene glycol amines with different n, R ¹ and R ^{2 in} the general formula (5) and maleic acid and maleic anhydride is used. May be. For the carboxyl group moiety, a free acid, a monovalent metal salt, a divalent metal salt, an ammonium salt, an organic amine salt, or the like can be used.

Examples of the monomer that gives the repeating unit (B) include imidized products of the polyoxyalkylene glycol amine represented by the general formula (5), maleic acid, and maleic anhydride. More than seeds can be used. When two or more types of monomers are used, an imidized product of two or more types of polyoxyalkylene glycol amines with different n, R ¹ and R ^{2 in} the general formula (5) and maleic acid and maleic anhydride is used. May be.

  Examples of the monomer that gives the repeating unit (C) include alkyl vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, isopropyl vinyl ether, isobutyl vinyl ether, 1,2-dimethoxyethylene, phenyl vinyl ether, and benzyl vinyl ether. Can be mentioned. These may be used alone or in combination of two or more. In particular, it is preferable to use a vinyl ether having relatively high hydrophilicity such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, and butyl vinyl ether from the viewpoint of water solubility of the copolymer. The monomer (b) that can be copolymerized with the monomer that gives the repeating units (A), (B), and (C) may be further copolymerized. Examples of the monomer (b) are as described above.

  The repeating unit of the copolymer (I) of the present invention preferably has a molar ratio of {(A) + (B)} / (C) = 1 to 99/99 to 1, preferably 10 to 90 / It is in the range of 90 to 10, more preferably 30 to 70/70 to 30, and most preferably 40 to 60/60 to 40.

  The weight average molecular weight of the copolymer (I) is 5,000 to 500,000, preferably 10,000 to 300,000, more preferably 12,000 to 200,000, more preferably in terms of polyethylene glycol equivalent weight average molecular weight. Is 15,000 to 150,000, more preferably 20,000 to 100,000, and still more preferably 22,000 to 80,000. If these component ratios and weight average molecular weights are out of the range, a cement additive that improves high water reduction performance and mortar kneading performance cannot be obtained.

  The cement additive of the present invention may be used as a main component of the cement admixture as it is in the form of an aqueous solution, or may be neutralized with a divalent metal hydroxide such as calcium or magnesium to obtain a polyvalent metal salt. After drying, it is dried by supporting it on inorganic powder such as silica-based fine powder, and it is dried and solidified into a thin film on a support using a drum-type drying device, disk-type drying device or belt-type drying device The powder may be pulverized and then pulverized for use. Also, the powdered cement additive of the present invention is blended in advance into a cement composition not containing water such as cement powder or dry mortar, and used as a premix product for plastering, floor finishing, grout, etc. Alternatively, it may be blended when the cement composition is kneaded.

  The cement additive of the present invention can be used for various hydraulic materials, that is, cement compositions such as cement and gypsum and other hydraulic materials. As a specific example of a hydraulic composition containing such a hydraulic material, water and the cement admixture of the present invention, and further containing fine aggregate (sand, etc.) and coarse aggregate (crushed stone, etc.) as necessary Examples include cement paste, mortar, concrete, plaster and the like.

  Among the hydraulic compositions, a cement composition using cement as a hydraulic material is the most common, and the cement composition includes the cement additive of the present invention, cement, and water as essential components. . Such a cement composition is one of the preferred embodiments of the present invention.

  There is no limitation in particular as a cement used in the said cement composition. For example, Portland cement (ordinary, early strength, very early strength, moderate heat, sulfate-resistant and low alkali type of each), various mixed cements (blast furnace cement, silica cement, fly ash cement), white Portland cement, alumina cement, Super fast cement (1 clinker fast cement, 2 clinker fast cement, magnesium phosphate cement), grout cement, oil well cement, low exothermic cement (low exothermic blast furnace cement, fly ash mixed low exothermic blast furnace cement, belite High-concentration cement), ultra-high-strength cement, cement-based solidified material, eco-cement (city waste incineration ash, sewage sludge incineration ash as a raw material), blast furnace slag, fly ash , Cinder ash, clinker ash, Squash, silica fume, silica powder, a fine powder and gypsum limestone powder may be added. In addition to gravel, crushed stone, granulated slag, recycled aggregate, etc., the aggregate includes siliceous, clay, zircon, high alumina, silicon carbide, graphite, chrome, chromic, magnesia. Refractory aggregate such as can be used.

In the cement composition, the unit water amount per 1 m ³ , the cement use amount and the water / cement ratio are as follows: unit water amount 100 to 185 kg / m ³ , use cement amount 200 to 800 kg / m ³ , water / cement ratio ( (Mass ratio) = 0.1 to 0.7, more preferably, unit water amount 120 to 175 kg / m ³ , amount of cement used 250 to 800 kg / m ³ , water / cement ratio (mass ratio) = 0. .2 to 0.65 is recommended, and can be used widely from poor blends to rich blends. The cement admixture of the present invention has a high water reduction rate region, that is, a region with a low water / cement ratio such as water / cement ratio (mass ratio) = 0.15 to 0.5 (preferably 0.15 to 0.4). In addition, it is effective for both high-strength concrete having a large unit cement amount and a small water / cement ratio, and poor-mixed concrete having a unit cement amount of 300 kg / m ³ or less.

  As a compounding ratio of the cement additive of the present invention in the cement composition, for example, when used for mortar or concrete using hydraulic cement, the cement mass is 0.01 to 10.0 mass in terms of solid content. % Is preferable. Such an added amount brings about various preferable effects such as reduction in unit water amount, increase in strength, and improvement in durability. If the blending ratio is less than 0.01%, the performance may not be sufficient. On the other hand, even if a large amount exceeding 10.0% is used, the effect is practically peaked and also from the economical aspect. May be disadvantageous. The preferred range of the blending ratio is more preferably 0.02 to 5.0% by mass, still more preferably 0.05 to 3.0% by mass, and particularly preferably 0.1 to 2.0% by mass. It is.

  The cement composition has high dispersibility and dispersion holding performance even in a high water reduction rate region, and exhibits sufficient initial dispersibility and viscosity reduction even at low temperatures, and has excellent workability. , Ready mixed concrete, concrete for concrete secondary products (precast concrete), centrifugal molding concrete, concrete for vibration compaction, steam-cured concrete, sprayed concrete, etc. High fluidity is required such as concrete in the range of 22-25 cm), high-fluidity concrete (concrete with a slump value of 25 cm or more and a slump flow value of 50-70 cm), self-filling concrete, self-leveling material, etc. It is also effective for mortar and concrete.

  The cement additive of the present invention can be used in combination with a known cement dispersant, and a plurality of known cement dispersants can be used in combination. As a well-known cement dispersant used together, the sulfonic acid-type dispersing agent (S) which has a sulfonic acid group in a molecule | numerator is preferable. By using a sulfonic acid-based dispersant (S) having a sulfonic acid group in the molecule, cement brand and lot no. Regardless of this, the cement admixture exhibits stable dispersion performance. The sulfonic acid dispersant (S) is a dispersant that exhibits dispersibility with respect to cement due to electrostatic repulsion mainly caused by sulfonic acid groups, and various known sulfonic acid dispersants can be used. A compound having an aromatic group in the molecule is preferable. Specifically, polyalkylaryl sulfonates such as naphthalene sulfonic acid formaldehyde condensate, methyl naphthalene sulfonic acid formaldehyde condensate, anthracene sulfonic acid formaldehyde condensate; melamine formalin resin sulfonate such as melamine sulfonic acid formaldehyde condensate Aromatic aminosulfonates such as aminoaryl sulfonic acid-phenol-formaldehyde condensates; lignin sulfonates such as lignin sulfonates and modified lignin sulfonates; various sulfonic acids such as polystyrene sulfonates System dispersants. In the case of concrete with a high water / cement ratio, a lignin sulfonate-based dispersant is preferably used, while in the case of a concrete with a medium water / cement ratio that requires higher dispersion performance, Dispersants such as alkylaryl sulfonate, melamine formalin sulfonate, aromatic amino sulfonate, and polystyrene sulfonate are preferably used. Two or more sulfonic acid-based dispersants (S) having a sulfonic acid group in the molecule may be used in combination.

  The cement additive of the present invention can be used in combination with the oxycarboxylic acid compound (D) in addition to the sulfonic acid dispersant (S). By including the oxycarboxylic acid compound (D), higher dispersion retention performance can be exhibited even in a high temperature environment. As the oxycarboxylic acid compound (D) used in the present invention, an oxycarboxylic acid having 4 to 10 carbon atoms or a salt thereof is preferable, for example, gluconic acid, glucoheptonic acid, aravic acid, malic acid, citric acid, These include inorganic or organic salts such as sodium, potassium, calcium, magnesium, ammonium, triethanolamine and the like. Among these, gluconic acid or a salt thereof is preferably used. In addition, these may be used independently and may use 2 or more types together. In particular, in the case of poor blended concrete, a lignin sulfonate-based dispersant is used as the sulfonic acid-based dispersant (S) having a sulfonic acid group in the molecule, and gluconic acid or oxycarboxylic acid-based compound (D) is gluconic acid or It is preferable to use the salt.

  When the cement admixture of the present invention and the sulfonic acid dispersant (S) are used in combination, the blending ratio of the copolymer (I) and the sulfonic acid dispersant (S) in the cement additive of the present invention, that is, The (copolymer (I) / sulfonic acid dispersant (S)) (% by mass) in terms of solid content is preferably from 1 to 99/99 to 1, more preferably from 5 to 95/95 to 5, 10-90 / 90-10 are more preferable, and 20-80 / 80-20 are especially preferable. Moreover, when using together the cement additive of this invention and an oxycarboxylic acid type compound (D), the compounding ratio of the copolymer (I) and the oxycarboxylic acid type compound (D) in the cement additive of this invention That is, (copolymer (I) / oxycarboxylic acid compound (D)) (mass%) in terms of solid content is preferably from 1 to 99/99 to 1, more preferably from 5 to 95/95 to 5. Preferably, 10-90 / 90-10 are more preferable, and 20-80 / 80-20 are especially preferable. Further, when the three components of the cement additive of the present invention, the sulfonic acid group dispersant (S) having a sulfonic acid group in the molecule and the oxycarboxylic acid compound (D) are used in combination, Copolymer (I), blending ratio of sulfonic acid-based dispersant (S) having a sulfonic acid group in the molecule and oxycarboxylic acid compound (D), that is, in terms of solid content (copolymer (I) / As the sulfonic acid-based dispersant (S) / oxycarboxylic acid-based compound (D)) (% by mass) having a sulfonic acid group in the molecule, 1 to 98/1 to 98/1 to 98 is preferable, 90 / 5-90 / 5-90 are more preferable, 10-90 / 5-85 / 5-85 are still more preferable, and 20-80 / 10-70 / 10-70 are especially preferable.

Moreover, the said cement composition can contain the other well-known cement additive (material) which is illustrated to the following (1)-(11).
(1) Water-soluble polymer material: polyacrylic acid (sodium), polymethacrylic acid (sodium), polymaleic acid (sodium), unsaturated carboxylic acid polymer such as sodium salt of acrylic acid / maleic acid copolymer; methylcellulose Nonionic cellulose ethers such as ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, hydroxypropyl cellulose; alkylated or hydroxyalkylated derivatives of polysaccharides such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose Hydrophobic substituents in which some or all of the hydroxyl atoms have a hydrocarbon chain having 8 to 40 carbon atoms as a partial structure, sulfonic acid groups or Polysaccharide derivatives substituted with an ionic hydrophilic substituent having a partial structure of these salts; yeast glucan, xanthan gum, β-1.3 glucans (which may be either linear or branched, examples include Polysaccharides produced by microbial fermentation such as curdlan, paramylon, pachyman, scleroglucan, laminaran, etc.); polyacrylamide; polyvinyl alcohol; starch; starch phosphate ester; sodium alginate; gelatin; A copolymer of acrylic acid having quaternary compounds and quaternary compounds thereof.
(2) Polymer emulsion: Copolymers of various vinyl monomers such as alkyl (meth) acrylate.
(3) Curing retarders other than oxycarboxylic acid compounds (D): 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 silicates; phosphoric acid and salts thereof or boric acid esters; Salt; Alkali-soluble protein; Humic acid; Tannic acid; Phenol; Polyhydric alcohol such as glycerin; Aminotri (methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediaminetetra (methylenephosphonic acid), diethylenetriamine Penta (methylenephosphonic acid) and these Alkali metal salts, and phosphonic acids and derivatives thereof such as alkaline earth metal salts.
(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; alkanolamine; alumina cement; calcium aluminate silicate.
(5) Antifoaming agents other than oxyalkylene-based: mineral oil-based antifoaming agents such as coconut oil and liquid paraffin; , Fatty acid-based antifoaming agents such as these alkylene oxide adducts; fatty acid ester-based antifoaming agents such as glycerin monoricinoleate, alkenyl succinic acid derivatives, sorbitol monolaurate, sorbitol trioleate, natural wax; octyl alcohol, hexadecyl Alcohol defoamers such as alcohol, acetylene alcohol and glycols; Amide defoamers such as acrylate polyamines; Phosphate ester defoamers such as tributyl phosphate and sodium octyl phosphate; Aluminum stearate, calcium oleate, etc. Metal soap defoaming ; Dimethyl silicone oil, silicone paste, silicone emulsion, organic modified polysiloxane (dimethyl polysiloxane polyorganosiloxane), silicone anti-foaming agent such as fluorosilicone oil.
(6) AE agent: resin soap, saturated or unsaturated fatty acid, sodium hydroxystearate, lauryl sulfate, ABS (alkyl benzene sulfonic acid), LAS (linear alkyl benzene sulfonic acid), alkane sulfonate, polyoxyethylene 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.
(7) Other surfactants: aliphatic monohydric alcohol having 6 to 30 carbon atoms in the molecule such as octadecyl alcohol and stearyl alcohol, and 6 to 30 carbon atoms in the molecule such as abiethyl alcohol Intramolecular such as alicyclic monohydric alcohol, dodecyl mercaptan, etc. Intramolecular such as monovalent mercaptan having 6-30 carbon atoms in the molecule, such as nonylphenol, alkylphenol having 6-30 carbon atoms in the molecule, dodecylamine, etc. 10 mol or more of an alkylene oxide such as ethylene oxide or propylene oxide was added to a carboxylic acid having 6 to 30 carbon atoms in the molecule such as an amine having 6 to 30 carbon atoms, lauric acid or stearic acid. Polyalkylene oxide derivatives having an alkyl group or an alkoxy group as a substituent Good, alkyl diphenyl ether sulfonates in which two phenyl groups having a sulfone group are ether-bonded; various anionic surfactants; various cationic surfactants such as alkylamine acetate and alkyltrimethylammonium chloride; various nonionic interfaces Activators; various amphoteric surfactants.
(8) Waterproofing agent: fatty acid (salt), fatty acid ester, oil and fat, silicon, paraffin, asphalt, wax and the like.
(9) Rust preventive: nitrite, phosphate, zinc oxide and the like.
(10) Crack reducing agent: polyoxyalkyl ether and the like.
(11) 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 used alone or in combination of two or more.

  In the above cement composition, the following (1) to (4) may be mentioned as particularly preferred embodiments for components other than cement and water.

  (1) <1> A combination that essentially comprises two components of the cement additive of the present invention and <2> an oxyalkylene-based antifoaming agent. As the oxyalkylene-based antifoaming agent, polyoxyalkylenes, polyoxyalkylene alkyl ethers, polyoxyalkylene acetylene ethers, polyoxyalkylene alkylamines and the like can be used, but polyoxyalkylene alkylamines are particularly preferable. Is preferred. The blending mass ratio of the oxyalkylene antifoaming agent <2> is preferably in the range of 0.01 to 20% by mass with respect to the cement admixture <1>.

  (2) A combination comprising two components of <1> the cement additive of the present invention and <2> a material separation reducing agent. Examples of the material separation reducing agent include various thickeners such as nonionic cellulose ethers, a hydrophobic substituent composed of a hydrocarbon chain having 4 to 30 carbon atoms as a partial structure, and an alkylene oxide having 2 to 18 carbon atoms. A compound having a polyoxyalkylene chain added in an average addition mole number of 2 to 300 can be used. The blending mass ratio of the cement admixture <1> and the material separation reducing agent <2> is preferably 10/90 to 99.99 / 0.01, and 50/50 to 99.9 / 0. 1 is more preferable. The cement composition of this combination is suitable as high fluidity concrete, self-filling concrete and self-leveling material.

  (3) A combination comprising two components, <1> the cement admixture of the present invention and <2> 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 mass ratio of the <1> cement admixture and the <2> accelerator is preferably 10/90 to 99.9 / 0.1, and more preferably 20/80 to 99/1.

  (4) A combination comprising essentially the three components of <1> the cement additive of the present invention, <2> an oxyalkylene antifoaming agent, and <3> an AE agent. As the oxyalkylene-based antifoaming agent, polyoxyalkylenes, polyoxyalkylene alkyl ethers, polyoxyalkylene acetylene ethers, polyoxyalkylene alkylamines and the like can be used, but polyoxyalkylene alkylamines are particularly preferable. Is preferred. The blending mass ratio of the cement additive <1> and the antifoaming agent <2> is preferably 0.01 to 20% by mass with respect to the cement additive <1>. On the other hand, the blending mass ratio of the AE agent <3> is preferably 0.001 to 2 mass% with respect to the cement.

The present invention will be described more specifically with reference to the following examples, but the present invention is not limited thereto. Unless otherwise specified, “%” represents mass% and “part” represents mass part.
<Conditions for measuring weight average molecular weight of copolymer>
Model: Waters LCM1
Detector: differential refractometer (RI) detector (Waters 410)
Eluent: Type Acetonitrile / 0.05M sodium acetate ion exchange aqueous solution = 40/60 (vol%), adjusted to pH 6.0 with acetic acid
Flow rate 0.6 ml / min Column: Type Tosoh Corporation “TSK-GEL G4000SWXL” + “G3000SWXL” + “G2000SWXL” + “GUARD COLUMN” 7.8 × 300 mm, 6.0 × 40 mm
Temperature 40 ℃
Calibration curve: Polyethylene glycol standard

Synthesis of ethyl vinyl ether / maleic anhydride copolymer (1) To a glass reaction vessel equipped with a thermometer, stirrer, nitrogen inlet tube and reflux condenser, maleic anhydride 35 g, ethyl vinyl ether 26 g and methyl ethyl ketone 613 g were added and stirred. While the reaction vessel was heated to 70 ° C., maleic anhydride was dissolved. Next, a solution in which 0.1 g of 2,2′-azobis (isobutyronitrile) was dissolved in 3 g of methyl ethyl ketone was added all at once and reacted at 70 ° C. for 6 hours. After completion of the reaction, methyl ethyl ketone was distilled off to obtain an ethyl vinyl ether / maleic anhydride copolymer (1) having a weight average molecular weight (Mw) of 28000.

Synthesis example 1
A glass reaction vessel equipped with a thermometer, stirrer, dropping funnel, nitrogen inlet, reflux condenser was charged with 2.5 g of ethyl vinyl ether / maleic anhydride copolymer (1) and 20 g of toluene. The coalescence was dissolved. Next, a solution in which 3.0 g of JEFAMINE M-2070 manufactured by Huntsman was dissolved in 20 g of toluene was dropped into the reaction vessel at 50 ° C. After completion of the dropping, the reaction temperature was raised to 80 ° C. and reacted for 5 hours. After completion of the reaction, toluene was distilled off with an evaporator, and water and an aqueous sodium hydroxide solution were added to adjust the pH to 7.0 to obtain a copolymer (1) of the present invention having a weight average molecular weight of 78,000.

Comparative Synthesis Example 1
A glass reaction vessel equipped with a thermometer, stirrer, dropping funnel, nitrogen inlet, reflux condenser was charged with 2.5 g of ethyl vinyl ether / maleic anhydride copolymer (1) and 20 g of dehydrated tetrahydrofuran, and both ethyl vinyl ether and maleic anhydride were mixed. The polymer was dissolved. Next, 0.043 g of sodium hydride was added to a solution in which 7.5 g of methoxypolyethylene glycol (average addition mole number of ethylene oxide 115) was dissolved in 20 g of dehydrated tetrahydrofuran to separately produce methoxypolyethylene glycol alkoxide. The solution was added dropwise to the reaction vessel at room temperature. After completion of the dropwise addition, the reaction temperature was maintained at 55 ° C. for 24 hours. After completion of the reaction, tetrahydrofuran was distilled off with an evaporator, and water and an aqueous sodium hydroxide solution were added to adjust the pH to 7.0 to obtain a comparative copolymer (1) having a weight average molecular weight of 67,100.

Next, the mortar which added the copolymer (1) of this invention and the comparative copolymer (1), respectively was prepared, and the flow value and the mortar uniform time were measured.

The material and mortar formulation used in the test were 600 g of Pacific ordinary Portland cement, 600 g of Toyoura standard sand, 210 g of water containing the copolymer (1) of the present invention or the comparative copolymer (1).

Mortar Test Method Mortar was prepared by kneading cement and sand at low speed for 30 seconds by mechanical kneading with a mortar mixer, and then adding water with agent and kneading for 3 minutes. The mortar uniform time was defined as the time when the mortar was in a uniform state visually. Next, 5 minutes after pouring the prepared mortar, the mortar was packed in a hollow cylinder having a diameter of 55 mm and a height of 50 mm, and then the cylinder was lifted vertically, and then the diameter of the mortar spread on the table was measured in two directions. This average value was taken as the flow value. The mortar after the flow measurement was further allowed to stand for 60 minutes, and then the mortar flow value was measured again by the above method. The results are shown in Table 1.

Next, long-term storage stability of the additive in an aqueous solution was confirmed.
40% aqueous solutions containing the copolymer (1) of the present invention and the comparative copolymer (1) were respectively prepared and allowed to stand at 50 ° C. for 1 week, and then the above mortar test was performed again.
The results are shown in Table 2.

Claims (2)

As a repeating unit, the following general formula (1)

(However, in the formula, R ¹ O represents one or a mixture of two or more oxyalkylene groups having 2 to 18 carbon atoms, and in the case of two or more types, R ¹ O is added in a random form even if it is added in a block form. R ² represents a hydrocarbon group having 1 to 30 carbon atoms, M ¹ represents hydrogen, a monovalent metal, a divalent metal, ammonium, an organic ammonium group, and n represents an average addition mole of an oxyalkylene group. And represents a number of 1 to 300.) and / or the following general formula (2)

(However, in the formula, R ¹ O represents one or a mixture of two or more oxyalkylene groups having 2 to 18 carbon atoms, and in the case of two or more types, R ¹ O is added in a random form even if it is added in a block form. R ² represents a hydrocarbon group having 1 to 30 carbon atoms, n represents an average added mole number of an oxyalkylene group, and represents a number of 1 to 300). And the following general formula (3)

(In the formula, R ³ represents a hydrocarbon group having 1 to 30 carbon atoms.)
A cement additive comprising a copolymer (I) containing a repeating unit (C) represented by As a repeating unit, the following general formula (4)

The repeating unit (D) represented by the following general formula (3)

(In the formula, R ³ represents a hydrocarbon group having 1 to 30 carbon atoms.)
In the acid anhydride part of the copolymer (II) containing the repeating unit (C) represented by the following general formula (5)

(However, in the formula, R ¹ O represents one or a mixture of two or more oxyalkylene groups having 2 to 18 carbon atoms, and in the case of two or more types, R ¹ O is added in a random form even if it is added in a block form. R ² represents a hydrocarbon group having 1 to 30 carbon atoms, and n represents the average number of added moles of an oxyalkylene group and represents a number of 1 to 300.)
A cement additive comprising a copolymer (III) obtained by amidation or imidization of one or more of the polyalkylene glycol amines (a) represented by