JP2010006701A - Method for producing cement admixture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production method easily producing a cement admixture which has high dispersion performance, gives a cured cement product excellent in strength and durability, and prevents fluidity from deteriorating at high temperature. <P>SOLUTION: The method for producing a cement admixture includes: preparing an unsaturated (poly)alkyleneglycol ether-based monomer (a) in the presence of a compound having active hydrogen other than unsaturated alcohols; and producing a copolymer (A) by conducting a copolymerization reaction using, as a starting material, a composition containing a monomer component containing the unsaturated (poly)alkyleneglycol ether-based monomer (a) and an unsaturated monocarboxylic acid-based monomer (b) as essential components, and a water-soluble polyalkyleneglycol (C) both ends of which are hydrogen atoms. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a method for producing a cement admixture.

  Cement compositions are widely used in applications such as building outer wall materials and building structures because they give a hardened cement product with excellent strength and durability. Examples of such a cement composition include cement paste in which water is added to cement, mortar in which sand that is fine aggregate is mixed, concrete in which pebbles that are coarse aggregate are further mixed, etc. Cement admixtures have been added to enhance air entrainment and fluidity, but in recent years, their importance has been recognized and technological innovation has been actively conducted.

  The mission of the cement admixture is to maintain sufficient fluidity and workability even when the cement composition is reduced in water, ensuring its fluidity and workability. There exists a place which acquires dispersibility and obtains a favorable cement composition. In the concrete industry in recent years, there is a strong demand for concrete that achieves such performance. To achieve this, reduction of unit water volume and prevention of fluidity deterioration are important issues.

  JP-A-9-214555 relates to a cement dispersant containing a polyoxyalkylene compound as an essential component, and JP-A-10-194808 discloses an alkenyl alcohol having a specific polyoxyalkylene chain and an unsaturated carboxylic acid system. The present invention relates to a cement dispersant composed of a copolymer having a compound as an essential constituent unit, and JP-A-11-106247 discloses an adduct of alkenyl alcohol with ethylene oxide and propylene oxide or an alkyl etherified product thereof as an essential constituent unit. It is disclosed that it may be used in combination with a retarder for a cement dispersant made of a copolymer.

  However, in these techniques, there has been room for contrivance to sufficiently prevent the fluidity of the cement composition from being lowered when it is constructed using the cement composition. That is, during the construction of the cement composition, a cement admixture for improving the fluidity of the cement composition is added as the hydrated reaction between the cement and water proceeds to partially form a cement hardened product. Since it is taken into the hardened cement product and can no longer exhibit its effect, there is room for further improvement in workability in the construction of the cement composition. In particular, when a cement composition is applied in a high-temperature environment, the fluidity of the cement composition is prevented from being lowered to improve workability, the cement composition is efficiently applied, and the cement is hardened sufficiently. It is desired to exhibit the performance of things.

Japanese Patent Laid-Open No. 9-241055 JP-A-10-194808 JP-A-11-106247

The present invention has been made in view of the above-described present situation, has a high dispersion performance, gives a cement cured product excellent in strength and durability, and can prevent a decrease in fluidity at high temperatures. An object of the present invention is to provide a method by which an admixture can be easily produced .

As a result of intensive studies on the cement admixture, the present inventors have first given that the copolymer (A) having a specific structural unit has a high dispersion performance and provides a cement cured product excellent in strength and durability. Pay attention. And when constructing a cement composition using such a cement admixture containing the copolymer (A), a specific amount of oxycarboxylic acid or salt thereof, sugar and sugar alcohol is used with respect to the copolymer (A). When used with one or more compounds selected from the group consisting of (B), it is maintained high dispersion performance and the like, moreover, been found that it is possible to prevent the lowering fluidity at high temperatures. Furthermore, in the method for producing the cement admixture, the step of preparing the unsaturated (poly) alkylene glycol ether monomer (a) in the presence of a compound having active hydrogen other than unsaturated alcohols, and A monomer component containing the saturated (poly) alkylene glycol ether monomer (a) and the unsaturated monocarboxylic acid monomer (b) as essential components, and a water-solubility in which both ends are hydrogen atoms By including a step of producing a copolymer (A) by carrying out a copolymerization reaction using a composition containing a polyalkylene glycol (C) as a raw material, the copolymer (A) and a water solution whose both ends are hydrogen atoms can be easily obtained. The present invention has been completed by finding that a cement admixture containing a functional polyalkylene glycol (C) can be obtained.

That is, the production method of the present invention comprises a copolymer (A) and one or more compounds (B) selected from the group consisting of oxycarboxylic acid or a salt thereof, sugar and sugar alcohol. A cement admixture that is included as an essential component in a ratio of 9 / 0.1 (% by weight), and the copolymer (A) has the following general formula (1);
YO (R ¹ O) nR ² (1)
(In the formula, Y represents an alkenyl group having 2 to 4 carbon atoms. R ¹ O is the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. N represents an average of oxyalkylene groups. Is an added mole number and represents a number of 1 to 500. R ² represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.) Unsaturated (poly) alkylene glycol ether-based monomer The structural unit (I) derived from the body (a) and the structural unit (II) derived from the unsaturated monocarboxylic acid monomer (b) as essential structural units, and the structural unit (I) and the structural unit unit (II) and are each accounts for 1 wt% or more in all the structural units, der 50 mol% or less in proportion of the structural unit (I) is the total structural units is, both end groups are hydrogen atom water Polyalkylene glycol (C) with respect to the copolymer (A) A method for producing a cement admixture containing about 50% by weight of the unsaturated (poly) alkylene glycol ether monomer (a) based on 1% to 100% by weight of the copolymer (A). A step of preparing the unsaturated (poly) alkylene glycol ether monomer (a) in the presence of a compound having active hydrogen other than unsaturated alcohols, and the unsaturated (poly) alkylene glycol ether type A monomer component containing the monomer (a) and the unsaturated monocarboxylic acid monomer (b) as essential components, and a water-soluble polyalkylene glycol (C) having hydrogen atoms at both ends. A step of producing a copolymer (A) by carrying out a copolymerization reaction using the composition as a raw material;

If the cement admixture of the present invention is added to the cement composition, it is possible to prevent a decrease in fluidity for a long time even at high temperatures such as in summer, and the cement composition is transferred by a pump or filled into a mold or the like. Workability in the process is improved. Moreover, according to the method for producing a cement admixture of the present invention, it is possible to easily produce a cement admixture containing a copolymer (A) and a water-soluble polyalkylene glycol (C) having hydrogen atoms at both ends. it can.

  The present invention will be described in detail below.

  The cement admixture according to the present invention comprises a copolymer (A) and at least one compound (B) selected from the group consisting of oxycarboxylic acid or a salt thereof, sugar and sugar alcohol, from 10/90 to 99.9. It is included as an essential component at a ratio (wt%) of /0.1. The said copolymer (A) is a copolymer for cement admixtures, exhibits a high dispersion performance in a cement composition, and can give the hardened | cured material excellent in intensity | strength and durability. In addition, one or more compounds (B) selected from the group consisting of the above oxycarboxylic acids or salts thereof, sugars and sugar alcohols can undergo a hydration reaction between cement and water when constructed using a cement composition. As the cement hardened product is partially formed as it progresses, the copolymer (A) or the like for improving the fluidity of the cement composition is taken into the cement hardened product and exerts its action. In order to sufficiently prevent the fluidity of the cement composition from being lowered due to the inability to do so, it has the effect of delaying hardening in the cement composition. By combining these copolymers (A) with one or more compounds (B) selected from the group consisting of oxycarboxylic acids or salts thereof, sugars and sugar alcohols, the copolymers can be used in the construction of cement compositions. The effect of (A) can be sufficiently exerted, and the fluidity can be prevented from lowering at high temperatures.

  The compound (B) used in the present invention is one or more compounds selected from the group consisting of oxycarboxylic acids or salts thereof, sugars and sugar alcohols. Examples of the oxycarboxylic acid or a salt thereof include gluconic acid, glucoheptonic acid, alabonic acid, malic acid, citric acid, and inorganic or organic salts such as sodium, potassium, calcium, magnesium, ammonium, triethanolamine, and the like. Is mentioned. In addition, as the sugar, monosaccharides such as glucose, fructose, galactose, saccharose, xylose, apiose, ribose and isomerized sugar, oligosaccharides such as disaccharide and trisaccharide, oligosaccharides such as dextrin, dextran, etc. Examples thereof include polysaccharides. Moreover, the molasses containing these are also contained. Furthermore, sorbitol etc. are mentioned as sugar alcohol. In these, it is preferable to use oxycarboxylic acid or its salt, and it is especially preferable to use gluconic acid or its salt. In addition, these may be used independently and may use 2 or more types together.

  Ratio of the copolymer (A) to one or more compounds (B) selected from the group consisting of oxycarboxylic acid or a salt thereof, sugar and sugar alcohol, that is, weight ratio (wt%) in terms of solid content As 10/90 to 99.9 / 0.1. When the proportion of the copolymer (A) is less than 10/90, the cement composition cannot be efficiently cured, and the proportion of the copolymer (A) is less than 99.9 / 0.1. If the amount increases, the dispersibility cannot be maintained during the construction of the cement composition. A preferable range of the ratio is 20/80 to 99/1. More preferably, it is 20/80 to 97/3.

  In the method for applying the cement composition of the present invention, the cement composition containing the cement admixture, cement and water as essential components is applied at a temperature of 20 ° C. or higher. Thereby, the fall of the fluidity | liquidity of a cement composition in the case of using the cement admixture which requires a copolymer (A) is prevented, and construction of a cement composition can be performed efficiently and easily. The construction method of such a cement composition is also one aspect of the present invention.

  In the construction method of the cement composition, when a cement admixture that essentially requires the copolymer (A) is used, the cement composition is excellent in fluidity, so that the work using the cement composition is efficient. Although it can carry out easily and easily, the effect by a copolymer (A) will fall that construction temperature is 20 degreeC or more. In the present invention, the construction temperature is 20 ° C. or higher by combining the copolymer (A) with one or more compounds (B) selected from the group consisting of oxycarboxylic acids or salts thereof, sugars and sugar alcohols. However, it is possible to prevent the effect of the copolymer (A) from being lowered and to perform the work in the construction of the cement composition efficiently and easily. As a preferable mode of the present invention, it is applied in construction in summertime, for example, when the construction temperature is 25 ° C. or higher. More preferably, it is 30 ° C. or higher. In the present invention, the term “construction” means a process in the construction or the like after the cement composition is prepared and until the cement composition is to be cured. For example, the cement composition is removed from the agitator car (green concrete mixer truck). ), Transporting by a pump, or filling a mold or the like. The construction temperature means the temperature of the cement composition when the cement composition is constructed.

  Below, a copolymer (A) and a cement composition are demonstrated. The copolymer (A) includes the structural unit (I) derived from the unsaturated (poly) alkylene glycol ether monomer (a) represented by the general formula (1) and an unsaturated monocarboxylic acid monomer. It is a polymer having the structural unit (II) derived from (b) as an essential structural unit. The copolymer (A) may have a structural unit (III) derived from the monomer (c) described later. Each of these structural units may be one kind or two or more kinds.

  In the copolymer (A), the structural unit (I) and the structural unit (II) each occupy 1% by weight or more of the total structural units, and the proportion of the structural unit (I) is 50% of the total structural units. It is less than mol%. When the proportion of the structural unit (I) is less than 1% by weight, the proportion of the oxyalkylene group derived from the unsaturated (poly) alkylene glycol ether monomer (a) present in the copolymer (A) is too small. In addition, when the proportion of the structural unit (II) is less than 1% by weight, the proportion of the carboxyl group derived from the unsaturated monocarboxylic acid monomer (b) present in the copolymer (A) is too small, It will not be possible to exhibit sufficient dispersibility. On the other hand, the proportion of the structural unit (I) is that the unsaturated (poly) alkylene glycol ether monomer (a) is low in polymerizability, so that a highly dispersible copolymer (A) is obtained in high yield. In order to obtain it, it is important that it is 50 mol% or less in all the structural units. Furthermore, in order to obtain a highly dispersible copolymer (A) with higher yield, it is preferable that the structural unit (II) comprises at least a structure derived from acrylic acid (salt). The proportion of the structural unit (I) is preferably 5% by weight or more, more preferably 10% by weight or more, still more preferably 20% by weight or more, and most preferably 40% by weight or more. Moreover, as a total ratio (% by weight) of the structural unit (I) and the structural unit (II) in the copolymer (A), 50 to 100% by weight of the entire copolymer (A) is preferable, and 70 to 100% by weight is more preferred.

In the general formula (1) representing the unsaturated (poly) alkylene glycol ether monomer (a), the number of carbon atoms of the oxyalkylene group R ¹ O is suitably 2-18, but 2-8 Is preferable, and 2-4 are more preferable. Moreover, any two or more types of alkylene oxide adducts selected from ethylene oxide, propylene oxide, butylene oxide, styrene oxide, etc. may be in any form such as random addition, block addition, and alternate addition. In order to secure a balance between hydrophilicity and hydrophobicity, the oxyalkylene group preferably has an oxyethylene group as an essential component, more preferably 50 mol% or more is an oxyethylene group, and 90 mol% or more. Is more preferably an oxyethylene group, and most preferably 95 mol% or more is an oxyethylene group.

  The average added mole number n of the oxyalkylene group in the general formula (1) is suitably 1 to 500. Preferably it is 2-500, More preferably, it is 10-500, More preferably, it is 20-500, Most preferably, it is 30-500, Most preferably, it is 40-300. The smaller the average added mole number, the lower the hydrophilicity of the resulting polymer and the lower the dispersion performance. On the other hand, when it exceeds 500, the copolymerization reactivity tends to decrease. The average added mole number means an average value of the number of moles of the organic group added in 1 mole of the monomer.

R ² in the general formula (1) may be 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, for example, 1 to 1 carbon atom. 30 alkyl groups (aliphatic alkyl groups or alicyclic alkyl groups), phenyl groups having 6 to 30 carbon atoms, alkylphenyl groups, phenylalkyl groups, phenyl groups substituted with (alkyl) phenyl groups, naphthyl groups, etc. And an aromatic group having a benzene ring. In R ² , the hydrophobicity increases as the number of carbon atoms of the hydrocarbon group increases, and the dispersibility decreases. Therefore, the number of carbon atoms when R ² is a hydrocarbon group is preferably 1 to 22, 18 is more preferable, and preferably 1 to 12 further particularly preferred 1 to 4, and when ^{R 2} is a hydrogen atom is most preferred.

  As a carbon atom number of the alkenyl group represented by Y in the said General formula (1), 2-4 are suitable, 3-4 are preferable and 4 is more preferable. Specific examples include a vinyl group, an allyl group, and a methallyl group, but an allyl group or a methallyl group is preferable, and a methallyl group is more preferable.

  Examples of the unsaturated (poly) alkylene glycol ether monomer (a) represented by the general formula (1) include 1 to 500 moles of alkylene oxide added to an unsaturated alcohol such as allyl alcohol or methallyl alcohol. Specifically, (poly) ethylene glycol (meth) allyl ether, (poly) ethylene (poly) propylene glycol (meth) allyl ether, (poly) ethylene (poly) butylene glycol ( And (meth) allyl ether. In the present invention, as the monomer (a) giving the structural unit (I), one of these can be used alone, or two or more can be used in combination.

  The structural unit (II) in the copolymer (A) preferably comprises at least a structure derived from acrylic acid (salt), and the unsaturated monocarboxylic acid monomer (b) is at least acrylic acid. Or it is preferable that the salt is included. By including a structure derived from acrylic acid or a salt thereof, excellent dispersibility can be exhibited in a small amount. Examples of the salt of acrylic acid include monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts. Further, the structural unit (II) may contain a structure other than the structure derived from acrylic acid or a salt thereof, and examples of the unsaturated monocarboxylic acid monomer (b) other than acrylic acid or a salt thereof include: , Methacrylic acid, crotonic acid, or monovalent metal salts, divalent metal salts, ammonium salts, organic amine salts, and the like thereof, and one or more of these can be used. Among these, as the unsaturated monocarboxylic acid monomer (b), a form containing only acrylic acid (salt) is preferable, but a form containing acrylic acid (salt) and methacrylic acid (salt) It is one of the preferred embodiments of the invention.

  In the copolymer (A), it is important that the proportion of the structural unit (II) is 1% by weight or more of all the structural units of the copolymer (A), but it is 2% by weight or more. It is preferably 3% by weight or more, more preferably 4% by weight or more. On the other hand, in the copolymer (A), the proportion of the structure derived from acrylic acid (salt) as the structural unit (II) is 0.5% by weight or more in the total structural units of the copolymer (A). It is preferably 1% by weight or more, more preferably 2% by weight or more, and particularly preferably 3% by weight or more.

  In the copolymer (A), the number of milliequivalents of carboxyl groups (meq / g) per 1 g of the copolymer (A) obtained by converting the carboxyl groups in the polymer (A) to an unneutralized type is The ratio of each structural unit is preferably set so as to be 0.2 to 5.0. The number of milliequivalents (meq / g) of the carboxyl group is more preferably 0.3 to 4.5, still more preferably 0.3 to 4.0, particularly preferably 0.4 to 3.5, and 4-3.0 is most preferred. When the number of milliequivalents of the carboxyl group is increased, the slump retention tends to be reduced, and when it is decreased, the initial dispersibility is decreased. Therefore, in the copolymer (A), the number of milliequivalents of carboxyl groups per 1 g of the copolymer (A) in which the carboxyl groups in the polymer (A) are converted to an unneutralized type (meq / g) Is preferably set so that the proportion of the structural unit (II) occupies the above range.

  The copolymer (A) may have other structural units having a carboxyl group in addition to the structural unit (II) having a carboxyl group derived from the unsaturated monocarboxylic acid monomer (b). Therefore, the number of milliequivalents of the carboxyl group of the copolymer (A) is not necessarily attributed to the carboxyl group derived from the structural unit (II). In consideration of this, it is necessary to set the upper limit of the proportion of the structural unit (II).

  The “number of milliequivalents of carboxyl groups per 1 g of the copolymer (A) in which the carboxyl groups in the copolymer (A) are converted to an unneutralized type (meq / g)” means the copolymer (A ) Considers the case of forming a salt, and the calculation method in the case of forming an acid and a salt is listed below. In the following calculation, only the carboxyl group derived from the structural unit (II) is illustrated, but when other structural units having a carboxyl group are included, this must also be included in the number of milliequivalents of the carboxyl group. Don't be.

  (Calculation Example 1): Acrylic acid was used as the monomer (b), and a copolymer having a composition ratio of monomer (a) / monomer (b) = 90/10 (% by weight) was obtained. In this case, since the molecular weight of acrylic acid is 72, the number of milliequivalents of carboxyl groups per 1 g of the polymer (meq / g) = ( 0.1 / 72) × 1000 = 1.39.

  (Calculation Example 2) Using sodium acrylate as the monomer (b), a copolymer having a composition ratio of monomer (a) / monomer (b) = 80/20 (% by weight) is obtained. In this case, since the molecular weight of sodium acrylate is 94 and the molecular weight of acrylic acid is 72, the carboxyl group derived from the monomer (b) is converted into an unneutralized type. Equivalent number (meq / g) = (0.2 × 72/94) / (0.8 + 0.2 × 72/94) /72×1000=2.23. In addition, it is the same as that of this calculation example also when acrylic acid is used at the time of superposition | polymerization and the carboxyl group derived from acrylic acid is completely neutralized with sodium hydroxide after superposition | polymerization.

  The number of milliequivalents of the carboxyl group (meq / g) is calculated by a calculation method based on the monomer as described above, and the type of the counter ion of the carboxyl group of the copolymer (A) is taken into consideration. Thus, it can also be calculated by measuring the acid value of the copolymer (A).

  The copolymer (A) includes, for example, an unsaturated (poly) alkylene glycol ether monomer (a) that provides the structural unit (I) and an unsaturated monocarboxylic acid monomer that provides the structural unit (II). Although it can manufacture by copolymerizing the monomer component which contains (b) as an essential component, it is not limited to this. For example, instead of the monomer (a), a monomer before addition of alkylene oxide, that is, an unsaturated alcohol such as methallyl alcohol, is used in the presence of a polymerization initiator. It can also be obtained by a method of adding 1 to 500 moles of an average of alkylene oxide after copolymerization. In addition, when copolymerizing a monomer component, you may further copolymerize the other monomer copolymerizable with the said monomer as needed.

  In the copolymer (A), other copolymerizable monomers (c) can be used in addition to the monomer component that gives the essential structural unit. The structural unit (III) is formed by such a monomer (c). The proportion of the structural unit (III) derived from the monomer (c) is preferably 70% by weight or less, and preferably 50% by weight or less in the total structural unit of the copolymer (A). More preferably, it is more preferably 30% by weight or less. The monomer (c) giving the structural unit (III) is a monomer copolymerizable with the monomer (a) and / or the monomer (b). 1 type or 2 types or more can be used.

  Unsaturated dicarboxylic acids such as maleic acid, maleic anhydride, fumaric acid, itaconic acid and citraconic acid, and monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts thereof; maleic acid, maleic anhydride, fumaric acid Half esters and diesters of unsaturated dicarboxylic acids such as acids, itaconic acid and citraconic acid and alcohols having 1 to 30 carbon atoms; half amides and diamides of unsaturated dicarboxylic acids and amines having 1 to 30 carbon atoms A half ester or a diester of an alkyl (poly) alkylene glycol obtained by adding 1 to 500 moles of an alkylene oxide having 2 to 18 carbon atoms to the alcohol or amine and the unsaturated dicarboxylic acid; and the unsaturated dicarboxylic acid or Glycols of 2 to 18 carbon atoms or addition moles of these glycols of 2 500 half-esters and diesters with polyalkylene glycol; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, glycidyl (meth) acrylate, methyl crotonate, ethyl crotonate, propyl crotonate, etc. Esters of unsaturated monocarboxylic acids and alcohols having 1 to 30 carbon atoms; alkoxy (poly) alkylene obtained by adding 1 to 500 moles of alkylene oxide having 2 to 18 carbon atoms to alcohol having 1 to 30 carbon atoms Esters of glycols with unsaturated monocarboxylic acids such as (meth) acrylic acid; (poly) ethylene glycol monomethacrylate, (poly) propylene glycol monomethacrylate, (poly) butylene glycol monomethacrylate, etc. 1 to 500 mol adducts of alkylene oxides having 2 to 18 carbon atoms to unsaturated monocarboxylic acids such as acrylic acid; maleamic acid and glycols having 2 to 18 carbon atoms or addition moles of these glycols of 2 to 2 Half amides with 500 polyalkylene glycols.

  (Poly) alkylene glycols such as triethylene glycol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, (poly) ethylene glycol (poly) propylene glycol di (meth) acrylate, etc. Di (meth) acrylates; polyfunctional (meth) acrylates such as hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane di (meth) acrylate; triethylene glycol dimaleate, polyethylene glycol (Poly) alkylene glycol dimaleates such as dimaleate; vinyl sulfonate, (meth) allyl sulfonate, 2- (meth) acryloxyethyl sulfonate, 3- (meth) acrylate Xylpropyl sulfonate, 3- (meth) acryloxy-2-hydroxypropyl sulfonate, 3- (meth) acryloxy-2-hydroxypropylsulfophenyl ether, 3- (meth) acryloxy-2-hydroxypropyloxysulfobenzoate, 4- ( Unsaturated sulfonic acids such as (meth) acryloxybutyl sulfonate, (meth) acrylamide methyl sulfonic acid, (meth) acrylamide ethyl sulfonic acid, 2-methylpropane sulfonic acid (meth) acrylamide, styrene sulfonic acid, and monovalents thereof Metal salts, divalent metal salts, ammonium salts and organic amine salts; amides of unsaturated monocarboxylic acids and amines having 1 to 30 carbon atoms such as methyl (meth) acrylamide; styrene, α-methylstyrene, vinyl tolue And vinyl aromatics such as p-methylstyrene; 1,4-butanediol mono (meth) acrylate, 1,5-pentanediol mono (meth) acrylate, 1,6-hexanediol mono (meth) acrylate, etc. Alkanediol mono (meth) acrylates; dienes such as butadiene, isoprene, 2-methyl-1,3-butadiene, 2-chloro-1,3-butadiene and the like.

  Unsaturated amides such as (meth) acrylamide, (meth) acrylalkylamide, N-methylol (meth) acrylamide, N, N-dimethyl (meth) acrylamide; unsaturated cyanides such as (meth) acrylonitrile and α-chloroacrylonitrile Unsaturated esters such as vinyl acetate and vinyl propionate; aminoethyl (meth) acrylate, methylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, Unsaturated amines such as dibutylaminoethyl acrylate and vinyl pyridine; divinyl aromatics such as divinylbenzene; cyanurates such as triallyl cyanurate; (meth) allyl alcohol, glycidyl (meth) allyl ether, etc. Allyls; Methoxypoly Tylene glycol monovinyl ether, polyethylene glycol monovinyl ether, methoxypolyethylene glycol mono (meth) allyl ether, polyethylene glycol mono (meth) allyl ether, and other vinyl ethers or allyl ethers; polydimethylsiloxanepropylaminomaleamic acid, polydimethylsiloxaneamino Propyleneaminomaleamic acid, polydimethylsiloxane-bis- (propylaminomaleamic acid), polydimethylsiloxane-bis- (dipropyleneaminomaleamic acid), polydimethylsiloxane- (1-propyl-3-acrylate), poly Dimethylsiloxane- (1-propyl-3-methacrylate), polydimethylsiloxane-bis- (1-propyl-3-acrylate) Siloxane derivatives such as polydimethylsiloxane-bis- (1-propyl-3-methacrylate).

  In order to obtain the copolymer (A) in the present invention, the monomer component may be copolymerized using a polymerization initiator. The copolymerization can be performed by a known method such as solution polymerization or bulk polymerization. The solution polymerization can be carried out batchwise or continuously, and the solvent used in that case is not particularly limited. For example, water; alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol; benzene, toluene, xylene, Aromatic or aliphatic hydrocarbons such as cyclohexane and n-hexane; ester compounds such as ethyl acetate; ketone compounds such as acetone and methyl ethyl ketone; cyclic ether compounds such as tetrahydrofuran and dioxane; It is preferable to use at least one selected from the group consisting of water and a lower alcohol having 1 to 4 carbon atoms because of the solubility of the obtained polymer. Among them, using water as a solvent can omit the solvent removal step. More preferable in terms.

  When aqueous solution polymerization is performed to produce the copolymer (A), a water-soluble polymerization initiator, for example, a persulfate such as ammonium persulfate, sodium persulfate, or potassium persulfate is used as a radical polymerization initiator. Hydrogen peroxide; azoamidine compounds such as 2,2′-azobis-2-methylpropionamidine hydrochloride; cyclic azoamidine compounds such as 2,2′-azobis-2- (2-imidazolin-2-yl) propane hydrochloride; Water-soluble azo initiators such as azonitrile compounds such as 2-carbamoylazoisobutyronitrile are used, and in this case, alkali metal sulfites such as sodium hydrogen sulfite, metabisulfites, sodium hypophosphite, molle Fe (II) salts such as salts, sodium hydroxymethanesulfinate dihydrate, hydroxylamine hydrochloride, thiourea, - ascorbic acid (salt), it may be used in combination accelerator such as erythorbic acid (salt). Among these, a combination of hydrogen peroxide and an accelerator such as L-ascorbic acid (salt) is preferable. These radical polymerization initiators and accelerators may be used alone or in combination of two or more.

  When performing solution polymerization using a lower alcohol, aromatic or aliphatic hydrocarbon, ester compound, or ketone compound as a solvent, peroxides such as benzoyl peroxide, lauroyl peroxide, and sodium peroxide; t-butyl Hydroperoxides such as hydroperoxide and cumene hydroperoxide; azo compounds such as azobisisobutyronitrile and the like are used as radical polymerization initiators. In this case, 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 radical polymerization initiators or combinations of radical polymerization initiators and accelerators.

  Furthermore, when performing bulk polymerization, as radical polymerization initiators, peroxides such as benzoyl peroxide, lauroyl peroxide and sodium peroxide; hydroperoxides such as t-butyl hydroperoxide and cumene hydroperoxide; azobisiso The reaction is performed at a temperature of 50 to 200 ° C. using an azo compound such as butyronitrile.

  The method of charging each monomer into the reaction vessel is not particularly limited. The method of initially charging the entire amount into the reaction vessel at once, the method of dividing or continuously charging the entire amount into the reaction vessel, and the initial charging into the reaction vessel. Any method may be used in which the remainder is divided or continuously charged into the reaction vessel. Specifically, a method in which all of monomer (a) and monomer (b) are continuously charged into a reaction vessel, a part of monomer (a) is initially charged into a reaction vessel, A method in which the remainder of (a) and all of monomer (b) are continuously charged into the reaction vessel, or a part of monomer (a) and a portion of monomer (b) are initially introduced into the reaction vessel. Examples of the method include charging and dividing the remainder of the monomer (a) and the remainder of the monomer (b) into the reaction vessel alternately in several times. In addition, by changing the charging rate of each monomer into the reaction vessel during the reaction continuously or stepwise, the weight ratio of each monomer charged per unit time can be changed continuously or stepwise. You may make it synthesize | combine the mixture of the copolymer from which the ratio of structural unit (I) and structural unit (II) in a polymer differs in a polymerization reaction. The radical polymerization initiator may be charged into the reaction vessel from the beginning, may be dropped into the reaction vessel, or may be combined in accordance with the purpose.

  A chain transfer agent can be used for adjusting the molecular weight of the copolymer (A). The chain transfer agent is not particularly limited. For example, mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, octyl thioglycolate, octyl 3-mercaptopropionate, 2 -Thiol chain transfer agents such as mercaptoethanesulfonic acid; secondary alcohols such as isopropanol; phosphorous acid, hypophosphorous acid, and salts thereof (sodium hypophosphite, potassium hypophosphite, etc.), sulfurous acid , Bisulfite, dithionite, metabisulfite, and salts thereof (sodium sulfite, potassium sulfite, sodium bisulfite, potassium bisulfite, sodium dithionite, potassium dithionite, sodium metabisulfite, metabisulfite Lower oxides of potassium sulfite and the like and salts thereof; It is below. These may be used alone or in combination of two or more. Furthermore, in order to adjust the molecular weight of the copolymer (A), it is also effective to use a monomer having high chain mobility such as (meth) allylsulfonic acid (salt) as the monomer (c). .

  The chain transfer agent may be any compound that can adjust the molecular weight. Specifically, mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, thioglycolic acid Thiol chain transfer agents such as octyl, octyl 3-mercaptopropionate, 2-mercaptoethanesulfonic acid, n-dodecyl mercaptan, octyl mercaptan, butylthioglycolate; halogens such as carbon tetrachloride, methylene chloride, bromoform, bromotrichloroethane Secondary alcohols such as isopropanol; phosphorous acid, hypophosphorous acid, and salts thereof (sodium hypophosphite, potassium hypophosphite, etc.), sulfurous acid, hydrogen sulfite, dithionic acid, meta heavy Sulfurous acid and its salts (sodium sulfite And the like can be used; potassium sulfite, sodium bisulfite, potassium bisulfite, sodium dithionite, potassium dithionite, sodium metabisulfite, lower oxides of potassium metabisulfite and the like), and salts thereof.

In order to obtain a copolymer with a predetermined molecular weight with good reproducibility, it is necessary to allow the copolymerization reaction to proceed stably. Therefore, in the case of solution polymerization, the dissolved oxygen concentration at 25 ° C. of the solvent used is 5 ppm. The following range is preferable. Preferably it is the range of 0.01-4 ppm, More preferably, it is the range of 0.01-2 ppm, Most preferably, it is the range of 0.01-1 ppm. When nitrogen substitution or the like is performed after the monomer is added to the solvent, the dissolved oxygen concentration of the system including the monomer is within the above range. The dissolved oxygen concentration in the solvent may be adjusted in a polymerization reaction tank, or a solution in which the amount of dissolved oxygen is adjusted in advance may be used. For example, the following (1) ) To (5).
(1) After pressurizing and filling an inert gas such as nitrogen into a sealed container containing a solvent, the partial pressure of oxygen in the solvent is lowered by lowering the pressure in the sealed container. You may reduce the pressure in an airtight container under nitrogen stream.
(2) The liquid phase portion is vigorously stirred for a long time while the gas phase portion in the container containing the solvent is replaced with an inert gas such as nitrogen.
(3) An inert gas such as nitrogen is bubbled in the solvent in the container for a long time.
(4) The solvent is once boiled and then cooled in an inert gas atmosphere such as nitrogen.
(5) A static mixer (static mixer) is installed in the middle of the pipe, and an inert gas such as nitrogen is mixed in the pipe for transferring the solvent to the polymerization reaction tank.

  The copolymer (A) is used as a main component of the cement admixture as it is, but from the viewpoint of handleability, it is preferably adjusted to a pH range of weak acid or higher in an aqueous solution state, more preferably It is in the range of pH 4 or more, more preferably pH 5 or more, particularly preferably pH 6 or more. On the other hand, the copolymerization reaction may be carried out at a pH of 7 or more, but in this case, the polymerization rate is lowered, and at the same time the copolymerizability is deteriorated and the dispersion performance is lowered. Therefore, the copolymerization is carried out in an acidic to neutral pH range. It is preferable to carry out the reaction, more preferably less than pH 6, more preferably less than pH 5.5, particularly preferably less than pH 5. Accordingly, it is preferable to adjust to a higher pH by adding an alkaline substance after carrying out the copolymerization reaction at a low pH. Specifically, as a preferred embodiment, the alkaline substance is specifically used after carrying out the copolymerization reaction at a pH of less than 6. To adjust the pH to 6 or more by adding a pH, to a method of adding an alkaline substance after carrying out a copolymerization reaction at a pH less than 5, and to add an alkaline substance after carrying out a copolymerization reaction at a pH of less than 5 The method etc. which adjust to pH6 or more are mentioned. The pH can be adjusted using, for example, an alkaline substance such as an inorganic salt such as a monovalent metal or divalent metal hydroxide or carbonate; ammonia; an organic amine; Also, when it is necessary to lower the pH, particularly when pH adjustment is required during polymerization, phosphoric acid, sulfuric acid, nitric acid, alkyl phosphoric acid, alkyl sulfuric acid, alkylsulfonic acid, (alkyl) benzenesulfonic acid, etc. It is possible to adjust the pH using an acidic substance, and among these acidic substances, phosphoric acid is preferred from the viewpoint of having a pH buffering action. Further, after the reaction, the concentration can be adjusted if necessary. The copolymer (A) may be used as a main component of the cement admixture as it is in the form of an aqueous solution, or it may be neutralized with a divalent metal hydroxide such as calcium or magnesium. It may be used after being made into a valent metal salt and dried, or supported on an inorganic powder such as silica fine powder and dried.

  The weight average molecular weight of the copolymer (A) is suitably 1000 to 500000 in terms of polyethylene glycol by gel permeation chromatography (hereinafter also referred to as “GPC”), preferably 5000 to 300000, and preferably 10,000 to 150,000. Is more preferable. By selecting such a weight average molecular weight range, a cement admixture exhibiting higher dispersion performance can be obtained.

  The cement admixture of the present invention is further water-soluble in addition to the copolymer (A), which is an essential component, and one or more compounds (B) selected from the group consisting of oxycarboxylic acids or salts thereof, sugars and sugar alcohols. It is preferable to contain 1-50 wt% of the functional polyalkylene glycol (C) with respect to the copolymer (A). More preferably, it is 2 to 50% by weight, further preferably 2 to 40% by weight, and particularly preferably 3 to 30% by weight. By containing the water-soluble polyalkylene glycol (C), it becomes a cement admixture that can further improve the workability of the cement composition such as mortar and concrete. When the content of the water-soluble polyalkylene glycol (C) is less than 1% by weight, the workability improvement effect is unsatisfactory. On the other hand, when the content exceeds 50% by weight, the dispersibility to cement is lowered. It is not preferable.

  The oxyalkylene group constituting the water-soluble polyalkylene glycol (C) is one or a mixture of two or more oxyalkylene groups having 2 to 18 carbon atoms, and the terminal group of the water-soluble polyalkylene glycol Is preferably a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, or an (alkyl) phenyl group. The number of carbon atoms of the oxyalkylene group of the water-soluble polyalkylene glycol (C) is suitably in the range of 2-18, preferably in the range of 2-8, and more preferably in the range of 2-4. Furthermore, since the water-soluble polyalkylene glycol (C) needs to be water-soluble, it preferably contains an oxyalkylene group having 2 hydrophilic carbon atoms, that is, an oxyethylene group as an essential component. More preferably, 50 mol% or more is an oxyethylene group, and more preferably 90 mol% or more is an oxyethylene group. In addition, the repeating unit of the oxyalkylene group may be the same or different. When the oxyalkylene group is in the form of a mixture of two or more, block addition, random addition, alternating addition, etc. Any of these additional forms may be used. The terminal group of the water-soluble polyalkylene glycol (C) is suitably a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, or an (alkyl) phenyl group, and the number of carbon atoms is preferably 1 to 22. 1-18 are more preferable, 1-12 are still more preferable, 1-4 are especially preferable, and the case of a hydrogen atom is the most preferable. The average molecular weight of the water-soluble polyalkylene glycol (C) is preferably in the range of 500 to 200,000, more preferably in the range of 1,000 to 100,000, and in the range of 2,000 to 50,000. Further preferred.

  Specific examples of the water-soluble polyalkylene glycol (C) in which both terminal groups are hydrogen atoms include polyethylene glycol, polypropylene glycol, polyethylene polypropylene glycol, polyethylene polybutylene glycol, and the like. Water-soluble polyalkylene glycol (C) Is preferably water-soluble, polyalkylene glycol having a highly hydrophilic oxyethylene group as an essential component is preferable, and polyalkylene glycol having 90 mol% or more of oxyethylene group as an essential component is more preferable. . Among these, polyethylene glycol or polyethylene polypropylene glycol is preferable, and polyethylene glycol is most preferable. Two or more types of water-soluble polyalkylene glycol (C) may be used. Since the water-soluble polyalkylene glycol (C) of the present invention needs to be water-soluble, a known oxyalkylene-based antifoaming agent that is essentially water-insoluble is used as the water-soluble polyalkylene glycol of the present invention. It cannot be used as glycol (C).

  The water-soluble polyalkylene glycol (C) may be added after the production of the copolymer (A), but when the copolymer (A) is produced, the unsaturated (poly) alkylene glycol ether type is used. In addition to the monomer component containing the monomer (a) and the unsaturated monocarboxylic acid monomer (b) as essential components, a composition containing a water-soluble polyalkylene glycol (C) is used as a raw material. By carrying out the polymerization reaction, a cement admixture containing the copolymer (A) and the water-soluble polyalkylene glycol (C) can be obtained.

  The unsaturated (poly) alkylene glycol ether monomer (a) used in the present invention can be obtained by adding 1 to 500 moles of alkylene oxide to unsaturated alcohols such as allyl alcohol and methallyl alcohol. However, during this addition reaction, if the reaction system contains a saturated aliphatic alcohol other than the unsaturated alcohol (methanol, ethanol, etc.) or a compound having active hydrogen such as water, the main product In addition to the monomer (a), a composition containing a polyalkylene glycol starting from the compound having active hydrogen as a by-product is obtained. In the present invention, polyalkylene glycol is used as a by-product in addition to the monomer (a) as a main product without removing the polyalkylene glycol by-produced during the production of the monomer (a). The following copolymerization reaction can be carried out using the composition containing the raw material, and a cement admixture containing the copolymer (A) and the water-soluble polyalkylene glycol (C) can be easily obtained by this production method. Can do. In the case where the polyalkylene glycol by-produced in the production of the monomer (a) is a polyalkylene glycol in which both end groups are hydrogen atoms, that is, polyethylene glycol, polyethylene polypropylene glycol or the like, 2 active hydrogens are added. The molecular weight of the polyalkylene glycol is higher than the molecular weight of the monomer (a) starting from an unsaturated alcohol having one active hydrogen, and is usually about the same. The average molecular weight is about twice. Further, after the production of the copolymer (A), a water-soluble polyalkylene glycol (C) may be further blended, and the water-soluble polyalkylene glycol (C) to be blended is water-soluble contained as a by-product. It may be the same as or different from the polyalkylene glycol (C).

  In the composition containing the unsaturated (poly) alkylene glycol ether monomer (a) and the water-soluble polyalkylene glycol (C) used for carrying out the copolymerization reaction, the unsaturated (poly) alkylene glycol ether type The ratio of the water-soluble polyalkylene glycol (C) to the monomer (a) is suitably 0.5 to 50% by weight, preferably 1 to 40% by weight, more preferably 2 to 30% by weight. 5 to 20% by weight is more preferable. In particular, when the proportion of the water-soluble polyalkylene glycol (C) exceeds 50% by weight, the monomer concentration during the polymerization reaction is lowered and the molecular weight of the copolymer (A) is lowered.

  The cement admixture of the present invention includes, in addition to the copolymer (A), which is an essential component, and one or more compounds (B) selected from the group consisting of oxycarboxylic acids or salts thereof, sugars and sugar alcohols. The unsaturated (poly) alkylene glycol ether monomer (a) represented by the general formula (1) is preferably contained in an amount of 1 to 100% by weight based on the copolymer (A). More preferably, it is 2-100 weight%, More preferably, it is 3-90 weight%, Especially preferably, it is 5-80 weight%. By containing the unsaturated (poly) alkylene glycol ether monomer (a), it becomes a cement admixture that can further improve the workability of the cement composition such as mortar and concrete. When the content of the unsaturated (poly) alkylene glycol ether monomer (a) is less than 1% by weight, the workability improvement effect is unsatisfactory, and when the content exceeds 100% by weight. Dispersibility with respect to cement is undesirably lowered. The unsaturated (poly) alkylene glycol ether monomer (a) is the unsaturated (poly) alkylene glycol ether monomer (a) used for the polymerization of the copolymer (A), that is, the copolymer (A). It may be the same as or different from the unsaturated (poly) alkylene glycol ether monomer (a) derived from the structural unit (I) of the polymer (A). Further, two or more kinds of unsaturated (poly) alkylene glycol ether monomers (a) may be used.

  The unsaturated (poly) alkylene glycol ether monomer (a) may be added after the production of the copolymer (A), but was used as a raw material when producing the copolymer (A). By stopping the polymerization reaction when the unsaturated (poly) alkylene glycol ether monomer (a) remains in an amount of 1 to 100% by weight with respect to the copolymer (A), the copolymer (A In addition to the above, a cement admixture composition containing 1 to 100% by weight of the unsaturated (poly) alkylene glycol ether monomer (a) based on the copolymer can be obtained. The point at which the polymerization reaction is stopped is more preferably a point at which 2 to 100% by weight of the unsaturated (poly) alkylene glycol ether monomer (a) remains in the copolymer (A). The time when 90% by weight remains is more preferable, the time when 4 to 80% by weight remains is particularly preferable, and the time when 5 to 70% by weight remains is most preferable. When the ratio of the remaining unsaturated (poly) alkylene glycol ether monomer (a) is less than 1% by weight, the workability improvement effect is unsatisfactory, and on the other hand, when it exceeds 100% by weight. However, it is not preferable because the dispersibility with respect to cement is lowered. In addition, after the production of the copolymer (A), an unsaturated (poly) alkylene glycol ether monomer (a) may be further blended, or the unsaturated (poly) alkylene glycol ether monomer ( a) may be the same as or different from the unsaturated (poly) alkylene glycol ether monomer (a) used as the monomer component for the copolymerization reaction.

  The cement admixture of the present invention includes, in addition to the copolymer (A), which is an essential component, and one or more compounds (B) selected from the group consisting of oxycarboxylic acids or salts thereof, sugars and sugar alcohols. The water-soluble polyalkylene glycol (C) is contained in an amount of 1 to 50% by weight based on the copolymer (A), and the unsaturated (poly) alkylene glycol ether monomer (a) is copolymerized (A Cement admixture that can shorten the setting time at low temperature and improve workability while maintaining the fluidity of the cement composition, particularly in the high water reduction rate region. It becomes.

  In addition to the copolymer (A), which is an essential component of the cement admixture of the present invention, and one or more compounds (B) selected from the group consisting of oxycarboxylic acids or salts thereof, sugars and sugar alcohols, 1 to 50% by weight of the functional polyalkylene glycol (C) with respect to the copolymer (A), and the unsaturated (poly) alkylene glycol ether monomer (a) in the copolymer (A) A preferable production method of the copolymer (A) for obtaining the cement admixture of the present invention containing 1 to 100% by weight with respect to the unsaturated (poly) alkylene glycol ether monomer (a) and In addition to the monomer component containing the unsaturated monocarboxylic acid monomer (b) as an essential component, a copolymerization reaction is carried out using a composition containing the water-soluble polyalkylene glycol (C) as a raw material. , Unsaturated (poly) alkylene glycol ether monomer (a) is a method of stopping the polymerization reaction at the time of remaining 1-100 wt% of the copolymer (A). By this method, a composition comprising three components of copolymer (A), unsaturated (poly) alkylene glycol ether monomer (a), and water-soluble polyalkylene glycol (C) can be obtained. The cement admixture of the present invention can be easily obtained by further adding one or more compounds (B) selected from the group consisting of oxycarboxylic acid or a salt thereof, sugar and sugar alcohol to the product.

  The cement admixture of the present invention contains a copolymer (A) and one or more compounds (B) selected from the group consisting of oxycarboxylic acids or salts thereof, sugars and sugar alcohols as essential components. In this form, it may be used as a main component of the cement admixture as it is, or it may be dried and powdered. When a cement admixture is added to the cement composition, the copolymer (A) is previously mixed with one or more compounds (B) selected from the group consisting of oxycarboxylic acids or salts thereof, sugars and sugar alcohols. The cement admixture may be added, or the copolymer (A) and one or more compounds (B) selected from the group consisting of oxycarboxylic acid or salts thereof, sugar and sugar alcohol may be added separately. May be.

  The cement admixture 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 that uses cement as a hydraulic material is the most common, and the cement composition includes the cement admixture 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, there is no particular limitation on the unit water amount per 1 m ³ , the cement usage amount, and the water / cement ratio, and the unit water amount 100 to 185 kg / m ³ , the cement amount used 250 to 800 kg / m ³ , water / Cement ratio (weight ratio) = 0.1 to 0.7, preferably unit water amount 120 to 175 kg / m ³ , used cement amount 270 to 800 kg / m ³ , water / cement ratio (weight ratio) = 0.2 to 0.65 is recommended, it can be used widely from poor blend to rich blend, high-strength concrete with a large amount of unit cement and a small water / cement ratio, low water / cement ratio (weight ratio) of 0.3 or less It is effective for both ultra-high-strength concrete in the water / cement ratio region and poor-mixed concrete having a unit cement amount of 300 kg / m ³ or less. The blending ratio of the cement admixture of the present invention in the cement composition is not particularly limited, but when used for mortar or concrete using hydraulic cement, the copolymer (A) in terms of solid content. And a total of one or more compounds (B) selected from the group consisting of oxycarboxylic acid or a salt thereof, sugar and sugar alcohol, 0.01 to 5.0% of cement weight, preferably 0.02 to 2 An amount of 0.0%, more preferably 0.05 to 1.0% may be added. By this addition, various preferable effects such as reduction in unit water amount, increase in strength, and improvement in durability are brought about. If the above blending ratio is less than 0.01%, the performance may not be sufficient. Conversely, even if a large amount exceeding 5.0% is used, the effect will substantially reach its peak and also from the economical aspect. Disadvantageous.

  The above cement composition is also excellent in pumpability, remarkably improves workability during construction, and has high fluidity. Therefore, ready mixed concrete, concrete for secondary concrete products (precast concrete), It is effective for centrifugal molding concrete, vibration compaction concrete, steam-cured concrete, shotcrete, etc. Furthermore, medium fluidity concrete (concrete with a slump value in the range of 22-25 cm), high fluidity concrete (slump value is 25 cm) Thus, it is also effective for mortar and concrete that require high fluidity, such as concrete having a slump flow value in the range of 50 to 70 cm, self-filling concrete, and self-leveling material.

  The cement composition can contain, for example, a cement dispersant as described below. Lignin sulfonate; polyol derivative; naphthalene sulfonic acid formalin condensate; melamine sulfonic acid formalin condensate; polystyrene sulfonate; aminoaryl sulfonic acid-phenol-formaldehyde condensate as described in JP-A-1-113419, etc. Aminosulfonic acid type; as described in JP-A-7-267705, as a component (a), a copolymer of a polyalkylene glycol mono (meth) acrylic acid ester compound and a (meth) acrylic acid compound and / or A salt thereof, and as a component (b), a copolymer of a polyalkylene glycol mono (meth) allyl ether compound and maleic anhydride and / or a hydrolyzate thereof, and / or a salt thereof, and a component (c) As polyalkylene glycol mono (meth) allylamine A cement dispersant containing a copolymer of a polyalkylene glycol and a maleic ester of a polyalkylene glycol compound and / or a salt thereof; (meth) acrylic acid as component A as described in Japanese Patent No. 2508113 A concrete admixture comprising a copolymer of a polyalkylene glycol ester of (meth) acrylic acid (salt), a specific polyethylene glycol polypropylene glycol compound as the B component, and a specific surfactant as the C component.

  A copolymer comprising polyethylene (propylene) glycol ester of (meth) acrylic acid, (meth) allylsulfonic acid (salt), and (meth) acrylic acid (salt) as described in JP-A-1-226757; As described in JP-B-5-36377, (meth) acrylic acid polyethylene (propylene) glycol ester, (meth) allylsulfonic acid (salt) or p- (meth) allyloxybenzenesulfonic acid (salt), and Copolymer comprising (meth) acrylic acid (salt); copolymer of polyethylene glycol mono (meth) allyl ether and maleic acid (salt) as described in JP-A-4-149056; JP-A-5-170501 (Meth) acrylic acid polyethylene glycol ester, (meth) allylsulfonic acid ( ), (Meth) acrylic acid (salt), alkanediol mono (meth) acrylate, polyalkylene glycol mono (meth) acrylate, and α, β-unsaturated monomer having an amide group in the molecule Copolymer: Copolymer of alkoxypolyalkylene glycol monoallyl ether and maleic anhydride, or a hydrolyzate or salt thereof as described in JP-A-5-43288; JP-B-58-38380 As described, polyethylene glycol monoallyl ether, maleic acid, and a copolymer comprising a monomer copolymerizable with these monomers, or a salt or ester thereof.

  As described in JP-B-59-18338, polyalkylene glycol mono (meth) acrylic acid ester monomer, (meth) acrylic acid monomer, and a monomer copolymerizable with these monomers A copolymer comprising a polymer; a copolymer comprising a (meth) acrylic acid ester having a sulfonic acid group and a monomer copolymerizable therewith as described in JP-A-62-1119147, or Salt thereof; as described in JP-A-6-271347, an esterification reaction product of a copolymer of an alkoxy polyalkylene glycol monoallyl ether and maleic anhydride and a polyoxyalkylene derivative having an alkenyl group at the terminal; Copolymer of alkoxypolyalkylene glycol monoallyl ether and maleic anhydride as described in Kaihei 6-298555 , An esterification reaction product of a polyoxyalkylene derivative having a hydroxyl group at the end. These cement dispersants may be used alone or in combination of two or more.

  When using the cement dispersant, the ratio of the copolymer (A) to the cement dispersant, that is, the weight ratio (% by weight) in terms of solid content, the copolymer (A) and the above The optimum ratio varies depending on the performance balance with the cement dispersant, but is preferably 1/99 to 99/1, more preferably 5/95 to 95/5, and most preferably 10/90 to 90/10.

Moreover, the said cement composition can contain the other well-known cement additive (material) which is illustrated to the following (1)-(20).
(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 A hydrophobic substituent in which some or all of the hydroxyl atoms have a hydrocarbon chain having 8 to 40 carbon atoms as a partial structure, a sulfonic acid group, or A polysaccharide derivative substituted with an ionic hydrophilic substituent having a salt as a partial structure; yeast glucan, xanthan gum, β-1.3 glucan (both linear and branched chains may be used. For example, Polysaccharides produced by microbial fermentation such as curdlan, paramylon, pachyman, scleroglucan, laminaran, etc.); polyacrylamide; polyvinyl alcohol; starch; starch phosphate ester; sodium alginate; gelatin; Acrylic acid copolymer and its quaternary compounds.
(2) Polymer emulsion: Copolymers of various vinyl monomers such as alkyl (meth) acrylate.
(3) Curing retarders other than one or more compounds (B) selected from the group consisting of oxycarboxylic acids or salts thereof, sugars and sugar alcohols: magnesium silicofluoride; phosphoric acid and salts thereof or boric acid esters; Aminocarboxylic acids and salts thereof; alkali-soluble proteins; humic acids; tannic acids; phenols; polyhydric alcohols such as glycerol; aminotri (methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediaminetetra (methylene Phosphonic acid), diethylenetriaminepenta (methylenephosphonic acid), and their alkali metal salts, alkaline earth metal salts, and the like.
(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) Mineral oil-based antifoaming agent: cocoon oil, liquid paraffin, etc.
(6) Fat and oil-based antifoaming agents: animal and vegetable oils, sesame oil, castor oil, and alkylene oxide adducts thereof.
(7) Fatty acid-based antifoaming agent: oleic acid, stearic acid, and these alkylene oxide adducts.
(8) Fatty acid ester antifoaming agent: glycerin monoricinoleate, alkenyl succinic acid derivative, sorbitol monolaurate, sorbitol trioleate, natural wax and the like.
(9) Oxyalkylene antifoaming agents: polyoxyalkylenes such as (poly) oxyethylene (poly) oxypropylene adducts; diethylene glycol heptyl ether, polyoxyethylene oleyl ether, polyoxypropylene butyl ether, polyoxyethylene polyoxypropylene (Poly) oxyalkyl ethers such as 2-ethylhexyl ether and oxyethyleneoxypropylene adducts to higher alcohols having 12 to 14 carbon atoms; (poly) oxy such as polyoxypropylene phenyl ether and polyoxyethylene nonylphenyl ether Alkylene (alkyl) aryl ethers; 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 2,5-dimethyl-3-hexyne-2,5-diol, 3-methyl-1 − Acetylene ethers obtained by addition polymerization of alkylene oxide to acetylenic alcohol such as tin-3-ol; (poly) oxyalkylene fatty acid esters such as diethylene glycol oleate, diethylene glycol laurate, ethylene glycol distearate; polyoxyethylene (Poly) oxyalkylene sorbitan fatty acid esters such as sorbitan monolaurate and polyoxyethylene sorbitan trioleate; (poly) oxyalkylene alkyls such as sodium polyoxypropylene methyl ether sulfate and sodium polyoxyethylene dodecylphenol ether sulfate ( Aryl) ether sulfate salts; (poly) oxyethylene stearyl phosphates, etc. Sialic sharp emission alkyl phosphate esters; polyoxyethylene such as polyoxyethylene lauryl amine (poly) oxyalkylene alkyl amines; polyoxyalkylene amide.
(10) Alcohol-based antifoaming agent: octyl alcohol, hexadecyl alcohol, acetylene alcohol, glycols and the like.
(11) Amide antifoaming agent: acrylate polyamine and the like.
(12) Phosphate ester antifoaming agent: tributyl phosphate, sodium octyl phosphate, etc.
(13) Metal soap type antifoaming agent: aluminum stearate, calcium oleate, etc.
(14) Silicone antifoaming agent: dimethyl silicone oil, silicone paste, silicone emulsion, organically modified polysiloxane (polyorganosiloxane such as dimethylpolysiloxane), fluorosilicone oil and the like.
(15) 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.
(16) Other surfactants: aliphatic monohydric alcohols having 6 to 30 carbon atoms in the molecule such as octadecyl alcohol and stearyl alcohol, and those having 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 or alkoxy group as a substituent 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 properties Surfactant; various amphoteric surfactants.
(17) Waterproofing agent: fatty acid (salt), fatty acid ester, oil and fat, silicon, paraffin, asphalt, wax and the like.
(18) Rust preventive: nitrite, phosphate, zinc oxide and the like.
(19) Crack reducing agent: polyoxyalkyl ether and the like.
(20) 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) A combination comprising two components of (i) the cement admixture of the present invention and (ii) an oxyalkylene-based antifoaming agent. In addition, as a compounding weight ratio of the oxyalkylene type | system | group antifoamer of (ii), the range of 0.001 to 10 weight% is preferable with respect to the copolymer (A) in the cement admixture of (i).

  (2) A combination comprising essentially two components (i) the cement admixture of the present invention and (ii) a material separation reducing agent. As a material separation reducing agent, 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 are added on average. A compound having a polyoxyalkylene chain having 2 to 300 moles added can be used. The blending weight ratio of the copolymer (A) in the cement admixture (i) and the material separation reducing agent (ii) is preferably 10/90 to 99.99 / 0.01, 50-99.9 / 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 in which two components of (i) the cement admixture of the present invention and (ii) a sulfonic acid-based dispersant having a sulfonic acid group in the molecule are essential. Examples of the sulfonic acid dispersant include lignin sulfonate, naphthalene sulfonic acid formalin condensate, melamine sulfonic acid formalin condensate, polystyrene sulfonate, aminoaryl sulfonic acid-phenol-formaldehyde condensate and the like. An agent or the like can be used. The blending weight ratio of the copolymer (A) in the cement admixture (i) to the sulfonic acid-based dispersant having a sulfonic acid group in the molecule (ii) is 5/95 to 95/5. Is preferable, and 10/90 to 90/10 is more preferable.

  (4) A combination comprising two components of (i) the cement admixture of the present invention and (ii) lignin sulfonate. The blending weight ratio of the copolymer (A) in the cement admixture of (i) and the lignin sulfonate of (ii) is preferably 5/95 to 95/5, and 10/90 to 90 / 10 is more preferable.

  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 weight% and “part” represents part by weight.

  In the production examples, the amount of polyalkylene glycol produced as a by-product during production of the unsaturated (poly) alkylene glycol ether monomer was measured under the following conditions.

<Measurement conditions for polyalkylene glycol production>
Model: Shimadzu Corporation LC-10
Detector: Differential refractometer (RI) detector (HITACHI 3350 RI MONITOR)
Eluent: Type Ion-exchanged water flow rate: 1.5 ml / min Column: Type Showa Denko K.K., “Shodex GF-310” 4.6 × 300 mm
Temperature: 40 ° C
In the production examples, the reaction rate of each monomer and the weight average molecular weight of the obtained copolymer were measured under the following conditions.

<Reaction rate measurement conditions for each raw material monomer>
Model: JASCO Borwin
Detector: Differential refractometer (RI) detector (HITACHI 3350 RI MONITOR)
Eluent: Type Acetonitrile / 0.1% Phosphate ion exchange aqueous solution = 50/50 (vol%)
Flow rate: 1.0 ml / min Column: Type Tosoh Co., Ltd., “ODS-120T” + “ODS-80Ts” each 4.6 × 250 mm
Temperature: 40 ° C
<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 x 300mm, 6.0 x 40mm each
Temperature: 40 ° C
Calibration curve: Polyethylene glycol standard <Production Example 1>
196 parts of methallyl alcohol (2-methyl-2-propen-1-ol) as an unsaturated alcohol and sodium hydroxide as an addition reaction catalyst in a stainless steel high-pressure reactor equipped with a thermometer, stirrer, nitrogen and alkylene oxide introduction tube 3.1 parts were charged, the inside of the reaction vessel was purged with nitrogen under stirring, and heated to 150 ° C. in a nitrogen atmosphere. And 6310 parts of ethylene oxide was introduce | transduced in the reactor, hold | maintaining 150 degreeC under safe pressure, and the temperature was hold | maintained until the alkylene oxide addition reaction was completed, and reaction was complete | finished. The obtained reaction product (hereinafter referred to as M-1) was an unsaturated polyalkylene glycol ether monomer (hereinafter referred to as MAL-50) obtained by adding an average of 50 moles of ethylene oxide to methallyl alcohol. In addition, water-soluble polyalkylene glycol (polyethylene glycol) was included as a by-product, and the amount of polyethylene glycol produced was 5.0% with respect to the unsaturated polyalkylene glycol ether monomer.

<Production Example 2>
A stainless steel high-pressure reactor equipped with a thermometer, stirrer, nitrogen and alkylene oxide introduction tube was charged with 105 parts of allyl alcohol as an unsaturated alcohol and 3.1 parts of sodium hydroxide as an addition reaction catalyst. Was replaced with nitrogen and heated to 150 ° C. in a nitrogen atmosphere. And 6195 parts of ethylene oxide was introduce | transduced in the reactor, hold | maintaining 150 degreeC under safety pressure, the temperature was hold | maintained until the alkylene oxide addition reaction was completed, and reaction was complete | finished. The obtained reaction product (hereinafter referred to as “M-2”) was used together with an unsaturated polyalkylene glycol ether monomer (hereinafter referred to as “AL-75”) obtained by adding an average of 75 moles of ethylene oxide to allyl alcohol. Water-soluble polyalkylene glycol (polyethylene glycol) was included as a by-product, and the amount of polyethylene glycol produced was 3.2% with respect to the unsaturated polyalkylene glycol ether monomer.

<Production Example 3-Production of Copolymer (A-1)>
Reaction reaction product obtained in Production Example 1 as an unsaturated polyalkylene glycol ether monomer in a glass reaction vessel equipped with a thermometer, stirrer, dropping funnel, nitrogen inlet tube and reflux condenser. 420 parts of product (M-1) (400 parts of MAL-50 and 20 parts of polyethylene glycol) were charged and heated to 65 ° C. With the reaction vessel kept at 65 ° C., an aqueous hydrogen peroxide solution consisting of 0.734 parts of hydrogen peroxide and 13.94 parts of ion-exchanged water was added. After maintaining the aqueous hydrogen peroxide solution at 65 ° C. for 30 minutes, 65.0 parts of acrylic acid was dropped into the reaction vessel over 3 hours, and at the same time, 0.05% of L-ascorbic acid was added to 18.05 parts of ion-exchanged water. An aqueous solution in which 950 parts and 1.718 parts of 3-mercaptopropionic acid were dissolved was dropped over 3.5 hours. Thereafter, the temperature was maintained at 65 ° C. for 1 hour, and then the polymerization reaction was terminated. The polymerization component concentration (weight percent concentration of all monomer components with respect to all raw materials) was 60%. Thereafter, the acidic reaction solution was neutralized to pH 7 using an aqueous sodium hydroxide solution at a temperature lower than the polymerization reaction temperature, and the copolymer (A-1) corresponding to the copolymer (A) of the present invention. A polymer aqueous solution containing was obtained. Moreover, when the residual amount of unsaturated polyalkylene glycol ether and acrylic acid obtained by adding 50 mol of ethylene oxide to methallyl alcohol on average was measured by liquid chromatography (LC) and the polymerization rate was determined, the unsaturated polyalkylene glycol ether was obtained. The polymerization rate was 94.1%, and the polymerization rate of acrylic acid was 97.0%. Accordingly, the copolymer composition ratio is unsaturated polyalkylene glycol ether / acrylic acid = 85.65 / 14.35 (wt%) = 15.9 / 84.1 (mol%), in terms of non-neutralized copolymer. The amount of carboxylic acid was 1.992 (meq / g). The copolymer (A-1) has a weight average molecular weight of 31,000, the content of the unsaturated polyalkylene glycol ether monomer to the neutralized copolymer is 5.14 (%), and the neutralized type. The content of water-soluble polyalkylene glycol (polyethylene glycol) relative to the copolymer was 4.36 (%).

<Production Example 4-Production of Copolymer (A-2)>
Reaction reaction product obtained in Production Example 2 as a glass reaction vessel equipped with a thermometer, stirrer, dropping funnel, nitrogen inlet tube and reflux condenser as ion-exchanged water and unsaturated polyalkylene glycol ether monomer 413 parts of product (M-2) (containing 400 parts of AL-75 and 13 parts of polyethylene glycol) was charged and heated to 80 ° C. With the reaction vessel kept at 80 ° C., an aqueous hydrogen peroxide solution consisting of 1.977 parts of hydrogen peroxide and 7.91 parts of ion-exchanged water was added. After maintaining the hydrogen peroxide solution for 30 minutes at 80 ° C., 43.8 parts of acrylic acid was dropped into the reaction vessel over 3 hours, and at the same time, L-ascorbic acid was added to 14.51 parts of ion-exchanged water. An aqueous solution in which 561 parts and 0.772 parts of 3-mercaptopropionic acid were dissolved was dropped over 3.5 hours. Thereafter, the temperature was maintained at 80 ° C. for 1 hour, and then the polymerization reaction was terminated. The polymerization component concentration (weight% concentration of all monomer components with respect to all raw materials) was 70%. Thereafter, the acidic reaction solution is neutralized to pH 7 using an aqueous sodium hydroxide solution at a temperature lower than the polymerization reaction temperature, and the copolymer (A-2) corresponding to the copolymer (A) of the present invention is used. A polymer aqueous solution containing was obtained. In addition, the residual amount of unsaturated polyalkylene glycol ether in which 75 moles of ethylene oxide was added to allyl alcohol and acrylic acid were measured by liquid chromatography (LC), and the polymerization rate was determined. The polymerization rate was 62.0%, and the polymerization rate of acrylic acid was 97.0%. Accordingly, the copolymer composition ratio is unsaturated polyalkylene glycol ether / acrylic acid = 85.38 / 14.62 (wt%) = 11.1 / 88.9 (mol%), in terms of non-neutralized copolymer. The amount of carboxylic acid was 2.030 (meq / g). The weight average molecular weight of the copolymer (A-2) is 36,500, the content of the unsaturated polyalkylene glycol ether monomer in the neutralized copolymer is 50.09 (%), and the neutralized type. The content of water-soluble polyalkylene glycol (polyethylene glycol) relative to the copolymer was 4.22 (%).
<Curing retarder>
The following were used as one or more compounds (B) selected from the group consisting of oxycarboxylic acids or salts thereof, sugars and sugar alcohols, and inorganic curing retarders (D).
(B-1) Sodium gluconate (B-2) Malic acid (B-3) Glucose (B-4) Sorbitol (D-1) Dipotassium hydrogen phosphate <Concrete test>
(Preparation of concrete composition)
A concrete composition was prepared with the following composition using ordinary Portland cement (manufactured by Taiheiyo Cement) as cement, Oikawa water-based land sand as fine aggregate, Qinghai crushed stone as coarse aggregate, and tap water as kneaded water. In addition, the material used for the test, the forced kneading mixer, and the measuring instruments are adjusted in the above test temperature atmosphere so that the temperature of the concrete composition is 30 ° C. or 15 ° C. Was conducted under the above-mentioned test temperature atmosphere. In order to avoid the influence of air bubbles in the concrete composition on the fluidity of the concrete composition, a commercially available oxyalkylene-based antifoaming agent is used as necessary, and the air amount is 1.0 ± 0.3%. It adjusted so that it might become.
(Combination)
Cement: 320 kg / ^{m 3,} water: 176 kg / ^{m 3,} fine aggregates: 822kg / ^{m 3,} coarse aggregate: 892kg / ^{m 3,} fine aggregate ratio (fine aggregate / fine aggregate + coarse aggregate) ( (Volume ratio): 48%, water / cement ratio (weight ratio) = 0.55
Concrete was produced in a kneading time of 2 minutes using a forced kneading mixer under the above conditions, and the slump value, setting time (end time) and air amount were measured. The slump value, setting time (end time), and air amount were measured in accordance with JIS-A-1101, JIS-A-6204, Annex I and JIS-A-1128, respectively. Addition of copolymer (A), oxycarboxylic acid or salt thereof, one or more compounds (B) selected from the group consisting of sugar and sugar alcohol, or inorganic curing retarder (D) in the table The amount indicates the weight% of the solid content [non-volatile component] to the cement, and the comparison was made by adjusting the addition amount so that the initial slump value was 20 ± 1 cm. In addition, solid content [nonvolatile component] in the polymer aqueous solution containing the copolymer (A) removes volatile components by weighing an appropriate amount of the polymer aqueous solution obtained in the above production example and heating and drying at 130 ° C. The polymer aqueous solution was weighed and used so that a predetermined amount of solid content [non-volatile component] was included when blended with cement. Accordingly, “(A) (solid content)” in the table is a non-volatile component other than the copolymer (A), that is, a solid containing a non-reacting monomer and a water-soluble polyalkylene glycol. This corresponds to the amount of [non-volatile component] and “(A) (polymer)” corresponds to the amount of solid [non-volatile component] of the copolymer (A) only. The “total” of the addition amounts in the table is based on “(A) (polymer)” corresponding to the solid content of the copolymer (A) alone, oxycarboxylic acid or a salt thereof, sugar and sugar alcohol. It is the total weight% of solid content with respect to the cement with one or more compounds (B) selected from the group consisting of or an inorganic curing retarder (D). The test results are shown in Table 1.

  As shown in Table 1, when the test temperature is 30 ° C. and the copolymer (A-1) or (A-2) is used alone, the inorganic curing retarder (D) is used in combination. In any case, the decrease in fluidity with time is large. On the other hand, one or more compounds (B-1), (B-2), (B), (oxycarboxylic acid or a salt thereof, sugar and sugar alcohol) are selected. When B-3) or (B-4) was used alone, sufficient fluidity could not be obtained. On the other hand, the copolymer (A-1) or (A-2) and one or more compounds (B-1) selected from the group consisting of oxycarboxylic acids or salts thereof, sugars and sugar alcohols (B-2) ), When the cement admixture of the present invention in combination with (B-3) or (B-4) was used, when the test temperature was 15 ° C., the decrease in fluidity with time was small, but the curing was slow. On the other hand, when the test temperature was 30 ° C., the decrease in fluidity with time was small and the curing was quick.

Claims (6)

The following copolymer (A) and one or more compounds (B) selected from the group consisting of oxycarboxylic acid or a salt thereof, sugar and sugar alcohol are 10/90 to 99.9 / 0.1. A cement admixture that is contained as an essential component in a proportion (% by weight),
The copolymer (A) has the following general formula (1):
YO (R ¹ O) nR ² (1)
(In the formula, Y represents an alkenyl group having 2 to 4 carbon atoms. R ¹ O is the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. N represents an average of oxyalkylene groups. Is an added mole number and represents a number of 1 to 500. R ² represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.) Unsaturated (poly) alkylene glycol ether-based monomer The structural unit (I) derived from the body (a) and the structural unit (II) derived from the unsaturated monocarboxylic acid monomer (b) as essential structural units, and the structural unit (I) and the structural unit Unit (II) each occupies 1% by weight or more of all the structural units, and the proportion of the structural unit (I) is 50 mol% or less in all the structural units,
1-50 wt% of water-soluble polyalkylene glycol (C) whose both terminal groups are hydrogen atoms with respect to the copolymer (A),
A method for producing a cement admixture comprising 1 to 100% by weight of the unsaturated (poly) alkylene glycol ether monomer (a) based on the copolymer (A) ,
Preparing the unsaturated (poly) alkylene glycol ether monomer (a) in the presence of a compound having an active hydrogen other than unsaturated alcohols; and
A monomer component containing the unsaturated (poly) alkylene glycol ether monomer (a) and the unsaturated monocarboxylic acid monomer (b) as essential components, and both ends thereof are hydrogen atoms A method for producing a cement admixture, comprising a step of producing a copolymer (A) by carrying out a copolymerization reaction using a composition containing a water-soluble polyalkylene glycol (C) as a raw material. The method further comprises a step of stopping the copolymerization reaction when the unsaturated (poly) alkylene glycol ether monomer (a) remains in an amount of 1 to 100% by weight based on the copolymer (A). Item 2. A method for producing a cement admixture according to Item 1. The method for producing a cement admixture according to claim 1 or 2 , wherein R ² is a hydrogen atom. The method for producing a cement admixture according to any one of claims 1 to 3, wherein the water-soluble polyalkylene glycol (C) is polyethylene glycol. The number of milliequivalents (meq / g) of carboxyl groups per 1 g of the copolymer (A) in which the carboxyl groups in the copolymer (A) are converted to an unneutralized type is 0.2 to 5.0. The method for producing a cement admixture according to any one of claims 1 to 4 . The method for producing a cement admixture according to any one of claims 1 to 5 , wherein the unsaturated monocarboxylic acid monomer (b) is acrylic acid or a salt thereof.