JP2000072505A - Cement admixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new mutifunctional cement admixture by preparing a copolymer containing an alkylene oxide derivative monomer, a carboxylic acid- based monomer, a silicone-based monomer and a sulfonic acid group-containing monomer at a specific ratio. SOLUTION: This cement admixture comprises 10-90 mol.% monomer comprising an alkylene oxide derivative represented by formula I [R1 is hydrogen or methyl group; R2 is hydrogen or 1-3C alkyl group; X is O, CH2O or COO; A is a 2-4C alkylene group alone or mixed alkylene group; (m) is an average polymerization degree of 5-100], 5-60 mol.% carboxylic acid-based monomer, 0.001-20 mol.% silicone-based monomer represented by formula II [R3 is hydrogen or methyl group; R4 to R8 are each 1-10C alkyl group or aryl group; (s) is an average polymerization degree of 1-500; (a) and (c) are each 0 or 1; (b) is 0-4] and 0-70 mol.% sulfonic acid group-containing monomer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a dispersant, a water reducing agent,
The present invention relates to a new multifunctional cement admixture which has excellent performance as a fluidizing agent and also has an effect of reducing concrete shrinkage, and a cement composition containing the cement admixture.

[0002]

2. Description of the Related Art Recently, higher requirements have been demanded for concrete in terms of function, quality, workability and the like. For example, high-strength concrete is demanded in terms of durability and strength in terms of function and quality, and in terms of workability, the need for high-fluidity concrete that does not require compaction by vibrators is increasing. In the production of these concretes, sulfonic acids such as naphthalene sulfonic acid formalin condensate, melamine sulfonate, amino sulfonate, etc., and carbon Acid cement admixtures are widely used. On the other hand, concrete has a serious drawback of drying shrinkage. Moreover, when the water / cement ratio is small or a large amount of fine powder material is used as in the case of the above-mentioned concrete, when the concrete is hardened, the self-shrinkage accompanying the decrease in the volume of the constituent minerals also overlaps, and cracks occur. In order to solve these problems, the conventional cement admixture has no effect, and it is necessary to newly use a shrinkage reducing agent. Examples of such a compound include a lower alcohol alkylene oxide adduct and a compound disclosed in JP-B-56-51148.
In JP-A No. 3 (KOKAI) No. 3, a polypropylene glycol derivative is used, and in Japanese Patent Publication No. 1-53214, an alkylene oxide derivative such as a polyhydric alcohol alkylene oxide adduct is used. However, high-fluidity concrete, drying shrinkage of high-strength concrete, and to suppress cracks caused by autogenous shrinkage, it is necessary to use a cement admixture, and the above shrinkage reducing agent in combination, in this case, In addition to the necessity of using a large amount of the shrinkage-reducing agent, there is a problem that the effect of reducing the shrinkage is insufficient.

[0003]

DISCLOSURE OF THE INVENTION The present invention has excellent performance as a dispersant, a water reducing agent, a fluidizing agent, etc.
Another object of the present invention is to provide a novel multifunctional cement admixture having a concrete shrinkage reducing effect and a cement composition containing the cement admixture.

[0004]

Means for Solving the Problems The present inventors have studied in detail the relationship between the chemical structure of a cement admixture and the effects of dispersing, fluidizing, and reducing shrinkage of concrete in order to solve the above-mentioned problems. As a result, the inventors have found that the above problem can be solved by incorporating a polysiloxane molecule into the cement admixture molecule, and have completed the present invention. That is, according to the present invention, monomers (a) 10 to 9 comprising an alkylene oxide derivative represented by the following general formula (1)
0 mol%, 5 to 60 mol% of a carboxylic acid monomer (b), 0.01 to 20 mol% of a silicone monomer (c) represented by the following general formula (2), and a sulfonic acid group-containing monomer ( d) A cement admixture characterized by comprising a copolymer containing 0 to 70 mol%. Further, according to the present invention, there is provided a cement composition containing the cement admixture.

Embedded image (Wherein, R ¹ : hydrogen or a methyl group, R ² : hydrogen or an alkyl group having 1 to 3 carbon atoms, X: O, CH ₂ O or COO, A: a single or mixed alkylene group having 2 to 4 carbon atoms, m: number of 5 to 100 in average polymerization degree)

Embedded image (Wherein, R ³ : hydrogen or methyl group, R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ : alkyl group or aryl group having 1 to 10 carbon atoms, X: O, CH ₂ O or COO, s : Number of average polymerization degree 1 to 500, a, c: number of 0 or 1, b: number of 0 to 4)

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The cement admixture of the present invention (hereinafter referred to as "the admixture")
Simply referred to as an admixture) is a copolymer containing the monomers (a) to (c) as its comonomer component and, if necessary, the monomer (d). The monomer (a) composed of an alkylene oxide derivative is represented by the general formula (1). In this case, R ¹
Is hydrogen or a methyl group. R ² is hydrogen or an alkyl group having 1 to 3 carbon atoms. Specific examples of the alkyl group include methyl, ethyl, n-propyl, iso-
Propyl. X is O, CH ₂ O or COO
Is shown. m is the average degree of polymerization of the oxyalkylene group,
5 to 100, preferably 6 to 50 from the viewpoint of the effect of dispersing concrete and the effect of maintaining fluidity over time. If the value of m is smaller than the above range, the resulting admixture will be insufficient in terms of the effect of dispersing concrete (mixed concrete or cement kneaded material) and maintaining fluidity. On the other hand, if it is larger than the above range, the resulting admixture tends to entrain air, which is not preferable. Examples of the alkylene oxide derivative include methoxy polyethylene glycol (meth) acrylate, ethoxy polyethylene glycol (meth) acrylate, propoxy polyethylene glycol (meth) acrylate, alkoxy polyethylene glycol polypropylene glycol (meth) acrylate, polyethylene glycol vinyl methyl ether, and polyethylene glycol Vinyl ethyl ether, polyethylene glycol vinyl propyl ether, polyethylene glycol polypropylene glycol vinyl alkyl ether, polyethylene glycol (meth) allyl methyl ether, polyethylene glycol (meth) allyl ethyl ether, polyethylene glycol (meth) allyl propyl ether, polyethylene glycol poly B is a propylene glycol (meth) allyl alkyl ether, the dispersion of the copolymer of the present invention, and to form a segment having a fluidity retaining effect. In the present invention, it is particularly preferable to use polyoxyalkylene glycol vinyl alkyl ether and polyoxyalkylene glycol (meth) allyl alkyl ether from the viewpoint of long-term stability of the cement admixture at high temperatures.

[0006] The monomer (b) is a carboxylic acid monomer. The monomers include unsaturated monocarboxylic acids, unsaturated polycarboxylic acids, or salts thereof. Specific examples thereof include acrylic acid, methacrylic acid, maleic acid, fumaric acid, and salts thereof. They are used alone or in combination. These monomer components mainly form a segment in which the copolymer of the present invention is entangled with the cement particles, and affect the dispersion, the reduction in shrinkage, and the efficiency thereof. In particular, when methacrylic acid or a salt thereof is used, the characteristic that selective adsorption to the cement mineral is small, and the amount of use is small depending on the quality and type of cement is exhibited.

The silicone-based monomer represented by the general formula (2)
In (c), R^ThreeIs hydrogen or a methyl group. R^FourYou
And R^FiveIs an alkyl group or aryl having 1 to 10 carbon atoms
And preferably an alkyl group. preferable
The alkyl group is a lower alkyl group having 1 to 4 carbon atoms,
Specific examples thereof include a methyl group, an ethyl group, and n-propyl.
Group, iso-propyl group, n-butyl group, tert-
Butyl group and the like. As the aryl group,
Examples include a nyl group, a tolyl group, and a xylyl group. X
Is O, CH_TwoO or COO. Preferably long
Product stability during early storage and high temperature during concrete construction
O or CH _TwoO.
a and c are 0 or 1. b is 0 to 5,
Preferably, it is 1-4. Silicone monomer
(C) exhibits the effect of reducing the shrinkage of the copolymer of the present invention.
Segment, average degree of polymerization s affects shrinkage reduction effect
I do. The range of s is 1 to 500. If s is less than 1,
Almost no shrinkage reducing effect is observed. s exceeds 500
The viscosity of the aqueous copolymer solution increases
Is not preferred. The remarkable s range of the shrinkage reduction effect is 2
1 to 500. Monomers having s in such a range
ー (c¹) Allows for immediate shrinkage reduction
The obtained copolymer can be obtained. On the other hand, if the range of s is 1
A monomer (c)^Two), Use s
A monomer (c) having a range of 21 to 500¹),
The resulting copolymer is inferior in the effect of reducing shrinkage, but other
(A) and (b), which are monomers of
Good copolymerizability to (d), unreacted in the copolymer
Characterized by low silicone monomer content
You. In particular, the monomer (c¹) And (c^Two)
It has good shrinkage reduction effect and
It is possible to prepare copolymers with low system monomer content.
Therefore, in the copolymer of the present invention, the monomer (c
¹) And a monomer (c^Two) Is preferred.

[0008] The monomer (d) is a monomer having a sulfonic acid group. As such a material, any one can be used as long as it can be copolymerized with the monomers (a) to (c). Such materials include vinylsulfonic acid, (meth) allylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-acrylamidoethanesulfonic acid, 2-methacrylamidoethanesulfonic acid, and 3-methacrylamidopropanesulfonic acid. Acid, styrene sulfonic acid or the like, or an alkali metal salt thereof, an anoleca earth metal salt, and an ammonium salt,
Organic ammonium salts such as amine salts and alkanolamine salts are exemplified. These monomers (d), together with the monomers (b), are not only involved in the bonding between the copolymer of the present invention and cement, but are also segments that impart a dispersing effect by electrostatic repulsion due to the negative charge of the sulfonic acid group. is there. Preferably, methallylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, and salts thereof are preferably used from the viewpoint of the dispersing effect and the like.

The copolymer used as an admixture in the present invention is:
The monomer (a)-
It contains the component (c) as an essential component and, if necessary, the monomer (d). The content of the monomer (a) is from 10 to 90 mol%, preferably from 20 to 70 mol% from the viewpoint of dispersion and the effect of maintaining fluidity over time. The total amount of the monomer (b) is 5 to 60 mol%, preferably 10 to 50 mol% from the viewpoint of the dispersing effect. The total amount of the monomer (c) is 0.01 to 20 mol%.
It is preferable to use a mixture of the monomer (c ¹ ) and the monomer (c ² ) from the viewpoint of the effect of reducing the shrinkage and the content of the unreacted silicone monomer in the copolymer. The content of the monomer (c ¹⁾ of the case, 0.01 to 2 mol%, preferably from 0.02 to 1 mol%. The content of the monomer (c ²⁾ is 0.1 to 20 mol%, preferably, 0.2 to 1
5 mol%. The content of the monomer (d) is from 0 to 70
Mol%, preferably 5 to 60 mol% from the viewpoint of the dispersing effect. The weight average molecular weight of the copolymer used in the present invention,
5,000 to 2,000,000, preferably 10,000
0 to 150,000. When the molecular weight of the copolymer is larger than the above range, the viscosity of the aqueous solution of the copolymer becomes high and handling becomes difficult. On the other hand, when the molecular weight is smaller than the above range, the dispersing effect and the shrinkage reducing effect are reduced.

[0010] The copolymer used in the present invention is obtained by copolymerizing the above-mentioned monomer by a known polymerization method such as solution polymerization, bulk polymerization, bulk polymerization, suspension polymerization, emulsion polymerization, and microsuspension polymerization using a polymerization initiator. It can be prepared by polymerization. Solution polymerization using a radical polymerization initiator is preferred in view of easiness of the polymerization operation and easiness of controlling the molecular weight of the produced copolymer. As the radical polymerization initiator, 2,2′-
Azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile, dimethyl-2,2'-azo Bisisobutyrate,
2,2′-azobis (2-methylbutyronitrile),
1,1′-azobis (1-cyclohexanecarbonitrile), 2,2′-azobis (2-amidinopropane) hydrochloride, 2,2′-azobis (N, N-dimethyleneisobutyroamidine) hydrochloride, etc. Azo compounds, t-benzyl octoate, dicumyl peroxide, di-t-butyl peroxide, dibenzoyl peroxide, lauroyl peroxide, t-butyl hydroperoxide, peroxides such as hydrogen peroxide, potassium persulfate, peroxide Inorganic peroxides such as ammonium sulfate, sodium perphosphate and potassium perphosphate are exemplified. The amount of these initiators used is 0.001 to 10.0 mol%, preferably 0.01 to 5.0 mol%, based on all monomers.

Solvents used for solution polymerization include ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; ester solvents such as ethyl acetate and butyl acetate; aromatic hydrocarbons such as benzene, toluene and xylene; Hexane, aliphatic hydrocarbons such as cyclohexane, methanol, ethanol, n-propanol, alcohols such as isopropanol, tetrahydrofuran, ethers such as dioxane, carbon tetrachloride,
In addition to halogenated hydrocarbons such as chloroform, cyclohexane, tetrahydrofuran, dimethylformamide, dimethylsulfonamide, water and the like can be mentioned. Preferred are ethanol, isopropanol and ethyl acetate. These solvents can be used alone or in combination of two or more. At the time of polymerization, a chain transfer agent can be used as needed for adjusting the molecular weight and viscosity. Such include mercaptoacetic acid, mercaptopropionic acid, dodecylmercaptan, thiophenol and the like. The polymerization temperature is 45 to 180 ° C. and the polymerization temperature is 3 to 10 hours. The polymerization conditions are appropriately selected depending on the type, ratio, concentration and the like of the monomer. When the polymerization temperature exceeds 180 ° C., thermal decomposition of the peroxide occurs, and in addition to a decrease in the polymerization rate, the formed hydrids cause a decrease in the initial fluidity. On the other hand, when the polymerization temperature is lower than 45 ° C., the polymerization rate decreases. By the above radical copolymerization, a copolymer having a low unreacted silicone monomer content can be obtained. In particular, a copolymer obtained by mixing the silicone-based monomer (c ¹ ) and (c ² ) has a good effect of reducing shrinkage and a small content of unreacted silicone-based monomer. Without using a special purification step for removing the solvent, after the polymerization reaction is completed, the solvent is distilled off from the reaction mixture or when water is used as the solvent, it is used as a copolymer of the present invention as it is. be able to. In addition, as long as the effects of the present invention are not impaired, one or more other copolymerizable monomers may be added to the polymerization components (a), (b), (c), and / or (d), or Two or more kinds may be used. Examples of such a monomer include, in addition to the silicone-based monomer represented by the following general formula (3), styrene, acrylonitrile, acrylamide, acrylate, methacrylate, vinyl acetate, maleate, fumarate, and the like. Is mentioned.

Embedded image In the above formula, R ³ represents hydrogen or a methyl group, R ^{6 to} R ¹⁴ represent hydrogen or an alkyl group having 1 to 3 carbon atoms, and X represents O, C
H indicates ₂ O or COO, a and c is a number of 0 or 1, b is a number of 0-4.

The cement admixture of the present invention can be used for all hydraulic cements such as ordinary Portland cement, early-strength Portland cement, moderately heated Portland cement, expanded cement, rapid-hardened cement, blast furnace cement, and alumina cement. . Of these, preferred are ordinary Portland cement and early strength Portland cement. In addition, a part of the cement can be replaced with a flysh, a blast furnace slag fine powder, a limestone fine powder, a siliceous admixture, or the like. The amount of the cement admixture of the present invention varies depending on the water-cement ratio and the slump, but is 0.01 to 5.0% by weight, preferably the shrinkage-reducing effect or the shrinkage-reducing effect, and the fluidizing effect. From the viewpoint of 0.1 to 3.0% by weight.
If it is less than 0.01% by weight, the effect of reducing shrinkage is small, while if it exceeds 5% by weight, it becomes excessively added and aggregate separation or
Lack of practicality due to exceeding the setting delay. The admixture of the present invention can be used in the form of an aqueous solution or powder.
It is the same as a normal high-performance water reducing agent or a high-performance AE water reducing agent, but as a method of adding the same, there are a method of adding late during the preparation of the cement kneaded material, a method of adding after the preparation, and the like. According to the method, shrinkage can be reduced together with an excellent fluidizing effect with a smaller amount of addition. When used in an aqueous solution, it is used not in cement but in kneading water. In the specification of the present application, as described above, the term "cement admixture" includes the case where it is added to a cement kneaded material or kneading water.

The cement admixture of the present invention can be used in combination with other components (optional components) when used. Such optional components include known cement hardening accelerators such as metal chlorides such as sodium chloride and the like, and organic amines such as monoethynolamine and triethanolamine; known well-known cement hardening accelerators such as alcohols, saccharides, starch, cellulose, glycerin and the like. Cement setting retarder: In addition to known reinforcing agents such as sodium nitrite and calcium nitrite, known AE agents, antifoaming agents, setting retarders, early-strength agents, aggregate separation reducing agents, thickeners Concrete admixtures such as water, water retention agent, waterproofing agent, swelling agent, polymer additive; ligninsulfonate, melaminesulfonate, aminosulfonate, naphthalenesulfonate formalin condensate, admixture with carboxylic acid cements of various chemical structures Agents and the like. Mortar or concrete using the cement admixture of the present invention can be applied in the same manner as in the prior art, such as ironing, filling into a mold, spraying, or pouring with a caulking gun. The curing method may be any of air-dry curing, wet-air curing, underwater curing, and heat-promoting curing, or a combination thereof.

The copolymer of the present invention is a multifunctional cement admixture having both a dispersing effect and a fluidity retaining effect, as well as a shrinkage reducing effect.
Alternatively, it is not necessary to use a high-performance AE water reducing agent and a shrinkage reducing agent in combination, and the work efficiency can be improved.

[0015]

The cement admixture of the present invention is characterized by a remarkable shrinkage reduction effect as compared with a conventional polyoxyalkylene glycol-based shrinkage reducing agent and a cement admixture used in combination. Therefore, the cement kneaded material using the cement admixture of the present invention can be used not only for ordinary concrete but also for high-strength concrete and high-fluidity concrete. Enables production of high-quality concrete.

[0016]

The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. still,
Samples of the copolymer used in the examples were prepared by the following method.

Reference Example 1 5 g (0.497 mmol) of a monomer (a ² ) having the following structure was placed in a four-necked flask having a capacity of 1000 ml and equipped with a reflux condenser, a dropping funnel, a thermometer and a gas inlet tube. And 100 ml of isopropanol (IPA) were stirred and uniformly dissolved by stirring. On the other hand, a dropping funnel (dropping funnel A
), A solution in which 1.2 g of 2,2'-azobis (2-methylbutyronitrile) was uniformly dissolved in 50 ml of IPA was added. In another dropping funnel (referred to as dropping funnel B),
58.2 g of a monomer (a ¹ ) having the structure shown below (0.0
5 mol) and polyoxyethylene methyl methacrylate [CH ₂ : C (CH ₃ ) COO (C ₂ H ₄ O) ₈ CH ₃ ] 36
2.0 g (0.8 mol), 17.2 g of methacrylic acid
(0.2 mol) was dissolved in 100 ml of IPA. The contents of the funnels A and B were added dropwise over 2 hours at 80 ° C. while heating in a flask under a nitrogen gas atmosphere in a nitrogen gas atmosphere. After aging at the same temperature for 3 hours, the mixture was cooled to room temperature to terminate the polymerization. Was. Subsequently, the content of the flask was reduced to 20 wt%.
Neutralized with aqueous sodium hydroxide solution, solid content 21.2w
A copolymer (A-1) solution having a t% of 55,000 (by GPC analysis) and a weight average molecular weight was obtained. Monomer (a ¹ ):

Embedded image Monomer (a ² ):

Embedded image

Reference Example 2 Polymerization was carried out in the same manner as in Reference Example 1, except that the types of monomers and the amounts charged were changed as follows. 271.5 parts by weight of polyoxyethylene methyl methacrylate [CH ₂ ＣC (CH ₃ ) COO (C ₂ H ₄ O) ₈ CH ₃ ] 13.8 parts by weight of methacrylic acid 2.9 parts by weight of acrylic acid 2-acrylamide 2 -Methylpropanesulfonic acid 41.4 parts by weight Silicone monomer (a ¹ ) of Reference Example 1 58.2 parts by weight Silicone monomer (a ² ) of Reference Example 1 30.2 parts by weight Polyoxyethylene methyl methacrylate, methacryl The molar ratio of the acid, acrylic acid, 2-acrylamide 2-methylpropanesulfonic acid, silicone monomer (a ¹ ), and silicone monomer (a ² ) is 0.6: 0.1
6: 0.04: 0.2: 0.05: 0.003.
The weight average molecular weight of the copolymer (A-2) obtained above is 4
8,000 (by GPC analysis).

Reference Example 3 The type of the monomer and the amount charged were changed as follows.
Further, polymerization was carried out according to Reference Example 1 except that the solvent was changed from isopropanol to toluene, and the polymerization initiator was changed from 2,2′-azobis (2-methylbutylnitrile to benzoyl peroxide). 0.2 parts by weight [CH ₂ = CHCH ₂ O (C ₂ H ₄ O) ₉ CH ₃ ] methacrylic acid 13.8 parts by weight Acrylic acid 12.9 parts by weight Monomer (a ¹ ) having the following structure 78.4 parts by weight Reference 30.2 parts by weight of the silicone monomer (a ² ) of Example 1 The molar ratio of polyoxyethylene allyl methyl ether, methacrylic acid, monomer (a ¹ ) and monomer (a ² ) was 0.1%.
6: 0.16: 0.04: 0.05: 0.003. The weight average molecular weight of the copolymer (A-3) obtained above was 21,000 (by GPC analysis). Monomer (a ¹ ):

Embedded image

Comparative Reference Example 1 Polymerization was carried out in the same manner as in Reference Example 1 except that the types of monomers and the amounts charged were changed as follows. Polyoxyethylene methyl methacrylate 226.3 parts by weight [CH ₂ ＣC (CH ₃ ) -COO (C ₂ H ₄ O) ₈ CH ₃ ] methacrylic acid 12.1 parts by weight Acrylic acid 4.3 parts by weight 2-acrylamide 62.2 parts by weight of 2-methylpropanesulfonic acid The molar ratio of polyoxyethylene methyl methacrylate, methacrylic acid, acrylic acid, 2-acrylamide 2-methylpropanesulfonic acid is 0.5: 0.14: 0.0
6: 0.3. The weight average molecular weight of the copolymer (Y-1) obtained above was 38,000 (by GPC analysis).

Example 1, Comparative Example 1 Each of the copolymers (A-1) to (A-
Using each copolymer (Y-1) obtained in 3) and Comparative Reference Example 1 as an admixture, the admixture was evaluated as follows. (Evaluation of cement admixture) First, coarse aggregate, fine aggregate, cement, and the admixture were put into a 50-liter pan-type forced kneading mixer in the order of 40 liters so that the volume became 40 liters.
After kneading for 2 seconds, a predetermined amount of a cement admixture dissolved in water was added and kneaded for 2 minutes. After kneading for a predetermined time, remove the mixture from the mixer and immediately follow JIS A11.
Slump was measured in accordance with JISA1.
The air volume was measured according to M.128. Further, the compressive strength and the dry shrinkage of the concrete having a hardness of 7 days and 14 days after were measured according to JIS A1108 and JIS A11, respectively.
The measurement was performed according to No. 29 (dial gauge method). Table 1 shows the evaluation results. The water / cement weight ratio is
30%, sand / cement weight ratio is 150%. Curing was carried out one week after curing in water, and then at 20 ° C and a relative humidity of 5 ° C.
The test was performed under a 0% atmosphere for a predetermined period.

[0022]

[Table 1]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08F 230/08 C08F 230/08 C08L 33/14 C08L 33/14 43/04 43/04 C04B 103: 32 ( 72) Inventor, Masaki Isoda, 1-3-7 Honsho, Sumida-ku, Tokyo, Japan (72) Inventor Kenji Yokoi 1-3-7, Honjo, Sumida-ku, Tokyo F-Term, Inc. Reference) 4J002 BE041 BG071 DM006 4J027 AC02 AC03 AC04 AC06 AC07 AF04 AF05 AJ02 AJ08 AJ09 BA02 BA03 BA04 BA05 BA06 BA07 BA13 BA14 CB02 CB03 CB09 CC02 4J100 AE09P AE09R AE18P AE18R AJ08P ABAQBAJ08BAJ08A

Claims (2)

[Claims] 1. A monomer (a) comprising an alkylene oxide derivative represented by the following general formula (1): 10 to 90 mol%, a carboxylic acid monomer (b) 5 to 60 mol%,
It is characterized by comprising a copolymer containing 0.01 to 20 mol% of a silicone monomer (c) represented by the following general formula (2) and 0 to 70 mol% of a sulfonic acid group-containing monomer (d). Cement admixture. Embedded image (Wherein, R ¹ : hydrogen or a methyl group, R ² : hydrogen or an alkyl group having 1 to 3 carbon atoms, X: O, CH ₂ O or COO, A: a single or mixed alkylene group having 2 to 4 carbon atoms, m: number of 5 to 100 in average degree of polymerization) (Wherein, R ³ : hydrogen or methyl group, R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ : alkyl group or aryl group having 1 to 10 carbon atoms, X: O, CH ₂ O or COO, s : Number of average polymerization degree of 1 to 500, a, c: number of 0 or 1, b: number of 0 to 4) 2. A cement composition comprising the cement admixture according to claim 1.