JP2000034151A - Cement admixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition having shrinkage reducing effects on a concrete by composing the cement admixture of a copolymer containing methoxypolyethylene glycol (meth)acrylate, a polyethylene glycol vinylalkyl ether, methacrylic acid and a sulfonate group-containing monomer. SOLUTION: This cement admixture is composed of a copolymer obtained by copolymerizing (A) a monomer represented by formula I [R1 denotes hydrogen or methyl; R2 demotes hydrogen or a 1-3C alkyl; X denotes O, CH2O or the like; (m) is the average degree of polymerization and denotes a number of 1-600] with (B) a monomer represented by formula II [R3 denotes hydrogen or methyl; R4 denotes a 1-24C aliphatic group; Y denotes O or CH2O; AO denotes a 2-4C oxyalkylene; (n) is the average degree of polymerization and denotes a number of 1-5 when the number of carbon atoms in R4 is 1-3 or denotes a number of 2-30 when the number of carbon atoms in R4 is 4-24], (C) a monomer represented by formula III (R5 denotes hydrogen or methyl; M denotes hydrogen or a salt-forming cation) and (D) a sulfonate group- containing monomer such as (meth)allylsulfonic acid in a prescribed ratio in the presence of a radical initiator, containing 10-80 mol.% of the component A, 5-70 mol.% of the component B, 5-70 mol.% of the component C and O-50 mol.% of the component D and having 5,000-200,000 weight-average molecular weight.

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, in order to produce high-fluidity concrete and high-strength concrete in which drying shrinkage, and cracks caused by self-shrinkage are suppressed, it is necessary to use a cement composition that uses a cement admixture and a shrinkage reducing agent together. Moreover, since the compounding amounts of these components are significantly different depending on the required quality of the concrete, the quality of the cement, the type thereof, the material of the aggregate, and the like, it is necessary to grasp the appropriate amounts of the respective components by preliminary tests in advance. Therefore,
In the case of producing concrete using a cement composition containing a conventional admixture and a shrinkage reducing agent, not only is the work complicated, but there is a problem that quality control of the cement composition is difficult. Improvement was required.

[0003]

DISCLOSURE OF THE INVENTION The present invention relates to a novel multifunctional cement admixture which has excellent performance as a dispersant, a superplasticizer and the like, and at the same time has an effect of reducing concrete shrinkage. It is an object of the present invention to provide a blended cement composition.

[0004]

The present inventors have studied in detail the relationship between the chemical structure of the cement admixture and the water reduction, fluidization and shrinkage reduction effects of concrete in order to solve the above-mentioned problems. As a result, they have found that the above problem can be solved by bonding a molecule imparting a shrinkage-reducing effect to the cement admixture molecule in a chemically stable form, and have completed the present invention. That is, according to the present invention, 10 to 80 mol% of the monomer (a) represented by the following general formula (1) and 5 to 5% of the monomer (b) represented by the following general formula (2)
The copolymer (A) contains 70 mol%, 5 to 70 mol% of a monomer (c) represented by the following general formula (3), and 0 to 50 mol% of a sulfonic acid group-containing monomer (d). A cement admixture is provided. Further, according to the present invention, 20 to 90 mol% of the monomer (a) represented by the following general formula (1), 5 to 70 mol% of the monomer (c) represented by the following general formula (3), and sulfonic acid 30 to 90% by weight of a copolymer (B) containing 0 to 50% by mole of a group-containing monomer (d), 10 to 90% by mole of a monomer (b) represented by the following general formula (2), and the following general formula (3)
Characterized in that the copolymer (C) comprises 5 to 70 mol% of a monomer (c) represented by the formula: and 10 to 70 wt% of a copolymer (C) containing 0 to 50 mol% of a sulfonic acid group-containing monomer (d). An admixture is provided. Further, according to the present invention, there is provided a cement composition containing the cement admixture. General formula (1):

Embedded image (Wherein, R ¹ represents hydrogen or a methyl group, R ² represents hydrogen or an alkyl group having 1 to 3 carbon atoms, X represents O, CH ₂ O or COO, and m represents an average degree of polymerization of 6 to 6. (Showing the number of 100) General formula (2):

Embedded image (Wherein, R ³ represents hydrogen or a methyl group, and R ⁴ has 1 carbon atom.
Indicates 24 aliphatic group, Y represents O or CH ₂ O,
AO represents a single or mixed oxyalkylene group having 2 to 4 carbon atoms, n represents an average degree of polymerization, and R ⁴ has 1 to 3 carbon atoms.
Represents the number of 1 to 5, and the carbon number of R ⁴ is ⁴ to 24.
Represents the number of 2 to 30). General formula (3):

Embedded image (Wherein, R ⁵ represents hydrogen or a methyl group, and M represents hydrogen or a salt-forming cation)

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The first cement admixture (hereinafter, also simply referred to as an admixture) of the present invention comprises a copolymer (A). The copolymer (A) contains monomers (a) to (c) as its copolymerized monomer component, and optionally contains a monomer (d). The monomer (a) is represented by the general formula (1). In this case, specific examples of R ² include methyl, ethyl, n-
Propyl, iso-propyl. X is O, C
H shows the ₂ O or COO. m is the average degree of polymerization of the oxyethylene group, and represents a number of 6 to 100, preferably 6 to 20. If the value of m is smaller than the above range, the resulting admixture will be insufficient in terms of the dispersion effect of concrete (mixed concrete or cement kneaded material) and the preservation of fluidity.
On the other hand, if it is larger than the above range, the resulting admixture has a property of entraining air, which is not preferable.
The average degree of polymerization m is particularly preferably set to 6 to 20 from the viewpoint of the concrete dispersing effect and the effect of maintaining the fluidity over time. Further, from the viewpoint of hydrolysis resistance, X is O or C
The use of the ether type of H ₂ O is preferred.
Examples of the monomer (a) include methoxy polyethylene glycol (meth) acrylate, ethoxy polyethylene glycol (meth) acrylate, propoxy (meth) acrylate, potiethylene glycol vinyl methyl ether, polyethylene glycol vinyl ethyl ether, polyethylene glycol vinyl propyl ether, Polyethylene glycol (meth) allyl methyl ether, polyethylene glycol (meth) allyl ethyl ether, polyethylene glycol (meth) allyl propyl ether and the like can be mentioned. This monomer (a) is a segment having the effect of dispersing and maintaining the fluidity of the cement admixture. In the present invention, it is particularly preferable to use polyoxyethylene (meth) allyl alkyl ether from the viewpoint of long-term stability of the cement admixture at high temperatures.

The monomer (b) is represented by the general formula (2). In this case, R ⁴ represents an aliphatic group.
The aliphatic group in this case includes a chain or cyclic alkyl group, and has 1 to 24 carbon atoms, preferably 1 to 18 carbon atoms.
It is. Specific examples of R ⁴ include methyl, ethyl, n-
Propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, hexyl, heptyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl,
Octadecyl, undecyl, 2-hexyldecyl, 2-
Octyldecyl, 2-nonyldecyl, 2-decyldodecyl, cyclohexyl, methylcyclohexyl, cyclooctyl and the like can be mentioned. Specific examples of the oxyalkylene group _{AO, C 2 H 4 O,} C 3 H 6 O, C 4 H 8 O, C 2 H 4 O
C ₃ H ₆ O and the like can be mentioned. n is the average degree of polymerization of AO, and represents the number of 1 to 30. When n is zero, the resulting admixture does not exhibit the effect of reducing concrete shrinkage. If n exceeds 30, the amount of bubbles increases, which is not preferable. The optimum range of n is selected from the viewpoint of the shrinkage reduction effect depending on the chain length of R ⁴ and the type of AO. When R ⁴ is a lower alkyl group having 3 or less carbon atoms, n represents a number of 1 to 5. R ⁴
When n is 4 or more, n is 2 to 30, preferably 3
~ 18. Specific examples of the monomer (b) include those having various substituents R ⁴ , such as polyethylene glycol vinyl alkyl ether, polypropylene glycol vinyl alkyl ether, polyethylene glycol polypropylene vinyl ether, and polyethylene glycol (meth) allyl alkyl ether. , Polypropylene glycol (meth) allyl alkyl ether,
Polyethylene glycol polypropylene glycol (meth) allyl alkyl ether; The monomer (b) is a segment that stably exhibits a concrete shrinkage reducing effect over a long period of time.

The monomer (c) is represented by the general formula (3). In this case, M includes salt-forming cations, such as ions of alkali metals such as sodium, potassium, lithium; calcium,
Alkaline earth metal ions such as magnesium; ammonium ions; substituted ammonium ions derived from alkanolamines and other organic amines. Specific examples of the monomer (c) include acrylic acid, methacrylic acid, and salts thereof. They are,
Used alone or in the form of a mixture. When used alone, methacrylic acid or a salt thereof is preferably used. The monomer (c) is mainly a segment for binding the admixture to the cement and the aggregate, and exerts a dispersing effect, a fluidity retaining effect, a shrinkage reducing effect, and an improvement in efficiency thereof. When methacrylic acid or a salt thereof is used, it is characterized by little selective adsorption to cement minerals and little variation in the amount used depending on the quality and type of cement and aggregate. When acrylic acid or a salt thereof is used, a cement admixture having a short kneading time can be obtained due to excellent initial fluidity. In the present invention, the monomer (c) is methacrylic acid and / or
Alternatively, it is preferable to use a monomer (c ¹ ) composed of a salt thereof and a monomer (c ² ) composed of acrylic acid and / or a salt thereof in combination. In this case, the molar ratio [c ¹ ] / [c ² ] between the monomer (c ¹ ) and the monomer (c ² ) is 98/2 to 50.
/ 50, preferably 95/5 to 60/40.

[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 vinyl sulfonic acid, (meth) allyl sulfonic acid,
-Acrylamide-2-methylpropanesulfonic acid, 2
-Acrylamidoethanesulfonic acid, 2-methacrylamidoethanesulfonic acid, 3-methacrylamidopropanesulfonic acid, styrenesulfonic acid and the like, and alkali metal salts, alkaline earth metal salts, ammonium salts, amine salts, alkanolamine salts thereof And the like. The monomer (d), together with the monomer (c), participates in binding the cement admixture with the cement and the aggregate, and also exhibits a dispersing effect due to electrostatic repulsion due to negative charge of the sulfonic acid group. In particular, it is a segment that exhibits a dispersing effect of a cement composition having a large water / cement ratio. Preferably, methallyl sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid and salts thereof are used from the viewpoint of the dispersion effect and the like.

In the copolymer (A), the content of the monomer (a) is from 10 to 80 mol%, preferably from 20 to 70 mol% in view of the effect of maintaining fluidity, and the content of the monomer (b)
Is from 5 to 70 mol%, preferably from 10 to 60 mol% from the viewpoint of the effect of reducing shrinkage, and the content of the monomer (c) is from 5 to 70 mol%, preferably from 1 to from the viewpoint of the dispersing effect.
0 to 60 mol%, and the content of the monomer (d) is 0 to 50 mol%.
Mol%, preferably 5 to 40 mol% in view of the dispersing effect at a high water / cement ratio. The molecular weight of the copolymer (A) is 5,000 to 200,000, preferably 10,000 to 160,000 in terms of weight average molecular weight. If the molecular weight of the copolymer (A) is larger than the above range, the viscosity of the aqueous solution of the admixture becomes high, handling becomes difficult, and the fluidity is significantly reduced. On the other hand, even if the molecular weight is smaller than the above range, the fluidity decreases.

[0010] The second cement admixture of the present invention comprises a mixture of a copolymer (B) and a copolymer (C). The copolymer (B) contains the above-mentioned monomer (a) and monomer (c) as its copolymerized monomer component, and optionally contains the monomer (d). The copolymer (C) contains a monomer (b) and a monomer (c) as a copolymerization monomer component, and optionally contains a monomer (d). In the copolymer (B), the content of the monomer (a) is as follows:
20-90 mol%, preferably 30-80 mol% from the viewpoint of dispersion and fluidity retention effect, the content of the monomer (c) is 5-70 mol%, preferably 10-60 mol from the viewpoint of shrinkage reduction effect. %, The content of the monomer (d) is from 0 to 5
0 mol%, preferably from 5 to 40 in view of the effect of maintaining fluidity.
Mol%. On the other hand, in the copolymer (C), the content of the monomer (b) is 10 to 90 mol%, preferably 15 to 80 mol% from the viewpoint of the shrinkage reducing effect, and the content of the monomer (c) is: 5 to 70 mol%, preferably 10
The content of the monomer (d) is 0 to 50 mol%, preferably 5 to 40 mol% from the viewpoint of the dispersing effect. In the copolymers (B) and (C) used in the present invention, the monomer (c) is a monomer (c ¹ ) composed of methacrylic acid and / or a salt thereof and a monomer (c ¹ ) composed of acrylic acid and / or a salt thereof ( Preferably, c ² ) is used in combination. In this case, the molar ratio [c ¹ ] / [c ² ] between the monomer (c ¹ ) and the monomer (c ² ) is from 98/2 to 50/50, preferably from 95/5 to 60/40. Copolymer (B)
And (C) have a weight average molecular weight of 5,000 to
200,000, preferably 10,000 to 160,0
00. If the molecular weights of the copolymers (B) and (C) are larger than the above ranges, the viscosity of the aqueous solution of the admixture becomes high, handling becomes difficult, and the fluidity is significantly reduced. On the other hand, even if the molecular weight is smaller than the above range, the fluidity decreases. The mixing ratio between the copolymer (B) and the copolymer (C) is as follows.
0% by weight, preferably 40 to 80% by weight and 10 to 70% by weight of the copolymer (C), preferably 20 to 60% by weight
It is.

The above copolymers (A), (B) and (C)
Can be prepared by copolymerizing the monomers by a method such as solution polymerization or bulk polymerization using a polymerization initiator. In the case of radical polymerization, examples of the polymerization initiator include organic peroxides such as di-t-butyl peroxide, benzoyl peroxide, lauroyl peroxide, azobisisobutyronitrile, sodium persulfate, ammonium persulfate, and persulfate. Inorganic peroxides such as potassium, sodium superphosphate and potassium superphosphate are exemplified. In the case of solution polymerization, as the solvent, benzene, toluene, aromatic hydrocarbons such as xylene,
Examples thereof include aliphatic hydrocarbons such as n-hexane and cyclohexane, ketones such as acetone and methyl ethyl ketone, ethers such as tetrahydrofuran and dioxane, halogenated hydrocarbons such as carbon tetrachloride and chloroform, and water. The polymerization temperature is 45 to 180 ° C. and the polymerization time is 3 to 10 hours, and 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 peroxide occurs,
In addition to a decrease in the polymerization rate, the produced polymer causes a decrease in the initial fluidity. On the other hand, when the polymerization temperature is lower than 45 ° C., the polymerization rate decreases. After completion of the polymerization reaction, when the solvent is distilled off from the reaction mixture or when water is used as the solvent, there is no need to remove the water, and the copolymer can be obtained as it is.

When synthesizing the copolymer (A), an initiator may be added to a mixture of the monomers (a), (b), (c) and / or (d). And the monomers (a), (b), (c) and / or
Alternatively, the component (d) and the initiator may be added at a predetermined ratio.
Further, the copolymer comprising the monomers (a), (b) and (c) may be graft-copolymerized with the monomer (d), or the copolymer comprising the monomers (a) and (c)
The monomer (b) may be graft-copolymerized to a copolymer composed of the component (d).

[0013] In addition, as long as the effects of the present invention are not impaired,
For the above monomer components (a), (b), (c) and / or (d), further copolymerized monomer components such as styrene, acrylonitrile, acrylamide, acrylate, methacrylate, vinyl acetate, An appropriate amount of maleic acid (salt), fumaric acid (salt), maleic ester, fumaric ester, or the like may be added and copolymerized.

The copolymer (B) used in the present invention
And (C) can be obtained in the same manner as in the case of the copolymer (A).

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 0.1 to 5.0% by weight, based on the fluidization effect and the shrinkage reduction effect. 1 to
It is in the range of 3.0% by weight. If it is less than 0.01% by weight,
If the fluidity of the cement kneaded material is low, on the other hand, if it exceeds 5% by weight, it will be excessively added, and it will be difficult to separate the aggregate and delay the setting, which is not practical. The admixture of the present invention can be used in the form of an aqueous solution or a powder, and the method of use is the same as that of a normal high-performance water reducing agent or a high-performance AE water reducing agent. There are a method of late addition during the preparation of the product, a method of post-addition after the preparation, and the like. By such a method, the shrinkage is reduced with an excellent fluidizing effect with a smaller addition amount. 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.

[0016] 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.

When the cement admixture of the present invention is used for cement, it is characterized in that it has a fluidizing effect, a water reducing effect, a reduction in shrinkage, and a reduction in strength. Further, in the case of the admixture of the present invention, it is not necessary to use a high-performance water reducing agent or a high-performance AE water reducing agent and a shrinkage reducing agent in combination as in the prior art, and the work efficiency can be improved. It is completely different in performance from a cement admixture containing an oxide chain as a part of the molecule.

[0018]

The cement admixture of the present invention has an excellent fluidizing effect and a shrinkage reducing effect as compared with the conventional carboxylic acid cement admixture. 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 the manufacture of

[0019]

Next, the present invention will be described in more detail with reference to examples. Reference Example 1 In a 2000 ml four-necked flask equipped with a reflux condenser, a dropping funnel and a gas inlet tube, polyoxyethylene allyl methyl ether (in the general formula (1), R ¹ =
H, R ² = CH ₃ , X = CH ₂ O, m = 9) 468.6 g
(1.0 mol), polyoxyethylene allyl isopropyl ether (in the general formula (2), R ³ = H, R ⁴ = i
_{so-C 3 H 7, Y} = CH 2 O, AO = C 2 H 4 O, n =
3) 92.4 g (0.4 mol), methacrylic acid 41.3
g (0.48 mol), 8.7 g (0.12 mol) of acrylic acid, and 300 ml of toluene were charged, and the flask was heated to 80 ° C. after purging with nitrogen. To this, 4.8 g of benzoyl peroxide was added dropwise over 7 hours. After dropping,
After stirring for 1 hour at the same temperature for aging, the solvent was distilled off under reduced pressure, and the generated solid content was dissolved in a 30 wt% aqueous solution of caustic soda to obtain a polymer having a weight average molecular weight of 18,000 (by GPC analysis). A combined (A-1) aqueous solution (pH 7.5) was obtained.

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. (1) Monomer (a) polyoxyethylene methyl methacrylate 226.3 parts by weight (ethylene oxide average polymerization degree m = 8) (2) Monomer (b) oxypropylene allyl methyl ether 130.2 parts by weight (propylene oxide average polymerization degree n = 1) (3) Monomer (c ¹ ) 31.0 parts by weight of methacrylic acid (4) Monomer (c ² ) 10.1 parts by weight of acrylic acid Polyoxyethylene methyl methacrylate, oxypropylene allyl methyl ether, methacrylic acid, acrylic acid The molar ratio is 25: 50: 18: 7. The weight average molecular weight of the copolymer (A-2) obtained above was 21,000.
(By GPC analysis).

Reference Example 3 Polymerization was carried out in the same manner as in Reference Example 1, except that the types of monomers and the charged amounts were changed as follows. (1) Monomer (a) 480.6 parts by weight of polyoxyethylene allylmethylethyl (average degree of ethylene oxide polymerization m = 12) (2) Monomer (b) Polyoxyethylene polyoxypropylene methallyl butyl ether (CH ₂ （C ( CH ₃ ) CH ₂ O (C ₃ H ₆ O) ₂ (C ₂ H ₄ O) ₂ C ₄ H ₉ ) 133.0 parts by weight (3) Monomer (c ¹ ) 41.3 parts by weight of methacrylic acid (4) Monomer (c ² ) 8.7 parts by weight of acrylic acid (5) Monomer (d) 41.4 parts by weight of 2-acrylamide 2-methylpropanesulfonic acid Polyoxyethylene allylmethylethyl, polyoxyethylene polyoxypropylene methallyl butyl ether , Methacrylic acid, acrylic acid, 2-acrylamide 2
-Methylpropanesulfonic acid molar ratio is 40: 20: 2
4: 6: 10. The weight average molecular weight of the copolymer (A-3) obtained above was 23,000 (by GPC analysis).

Reference Example 4 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. (1) Monomer (a) Polyoxyethylene methallyl methyl ether 386.1 parts by weight (CH ₂ ＣC (CH ₃ ) O (C ₂ H ₄ O) ₉ CH ₃ ) (2) Monomer (b) Polyoxyethylene Allyl isopropyl ether 110.6 parts by weight (CH ₂ ＣＨCHCH ₂ O (C ₂ H ₄ O) ₄ iso-C ₃ H ₆ ) (3) Monomer (C ¹ ) 41.3 parts by weight of methacrylic acid (4) Monomer ( C ² ) 8.7 parts by weight of acrylic acid (5) monomer (d) 41.4 parts by weight of 2-acrylamide 2-methylpropanesulfonic acid polyoxyethylene methallyl methyl ether, polyoxyethylene allyl isopropyl ether, methacrylic acid, acrylic The molar ratio of the acid and 2-acrylamide 2-methylpropanesulfonic acid is 40: 20: 24: 6: 10. The weight average molecular weight of the copolymer (A-4) obtained above was 15,000 (by GPC analysis).

Reference Example 5 Polymerization was carried out in the same manner as in Reference Example 1, except that the types of monomers and the charged amounts were changed as follows. (1) Monomer (a) 454.6 parts by weight of polyoxyethylene vinyl methyl ether (average degree of polymerization of ethylene oxide m = 9) (2) Monomer (b) 181.4 parts by weight of polyoxyethylene vinyl cyclohexyl ether (average degree of polymerization of ethylene oxide n = 4) (4) Monomer (C) 34.4 parts by weight of methacrylic acid Polyoxyethylene vinyl methyl ether, polyoxyethylene vinyl cyclohexyl ether, methacrylic acid molar ratio is 50:30:20. The weight average molecular weight of the copolymer (A-5) obtained above was 2,000 (by GPC analysis).

Comparative Reference Example 1 The procedure of Reference Example 1 was followed, except that the type of monomer and the amount charged were changed as described below. 496.6 parts by weight of polyoxyethylene methyl methacrylate (average degree of polymerization of ethylene oxide = 9) 86.1 parts by weight of propylene glycol ethyl methacrylate (average degree of polymerization of propylene = 1) 31.0 parts by weight of methacrylic acid 10.1 parts by weight of acrylic acid The molar ratio of polyoxyethylene methyl methacrylate, propylene glycol ethyl methacrylate, methacrylic acid, acrylic acid is 50: 25: 18: 7. The weight average molecular weight of the copolymer (Y-1) obtained above was 20,000.
0 (by GPC analysis).

Comparative 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. 212.3 parts by weight of polyoxyethylene allyl methyl ether (average degree of polymerization of ethylene oxide = 8) polyoxyethylene polyoxypropylene methallyl butyl ether (CH ₂ ＣC (CH ₃ ) CH ₂ O (C ₃ H ₆ O) ₂ (C _{2 H 4 O) 2 C 4} H 9) 286.7 parts by weight of acrylic acid 43.3 parts by weight of polyoxyethylene allyl methyl ether, polyoxyethylene polyoxypropylene methallyl ether, acrylic acid molar ratio 25:45:30 It is. The weight average molecular weight of the copolymer (Y-2) obtained above was 32.0.
00 (by GPC analysis).

Comparative Reference Example 3 Polymerization was carried out in the same manner as in Reference Example 1 except that the types of monomers and the charged amounts were changed as follows. 281.2 parts by weight of polyoxyethylene allyl methyl ether (average degree of polymerization of ethylene oxide = 9) polyoxyethylene polyoxypropylene allyl butyl ether (average degree of polymerization of ethylene oxide and propylene oxide is 2) 254.8 parts by weight Methacrylic acid 51.7 parts by weight Part Polyoxyethylene allyl methyl ether, polyoxyethylene polyoxypropylene allyl butyl ale, methacrylic acid molar ratio is 30:40:30. The weight average molecular weight of the copolymer (Y-3) obtained above was 2,000.
(By GPC analysis).

Examples 1 to 5 and Comparative Examples 4 to 6 Each of the copolymers (A-1) to (A-
5) and each copolymer (Y-1) obtained in Comparative Reference Examples 1 to 3
-(Y-3) was used as an admixture, and 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
50%, the sand / cement weight ratio is 200%. 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.

[0028]

[Table 1] * Weight% of solid content of admixture to cement

Reference Example 6 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. (1) Monomer (a) 656.0 parts by weight of polyoxyethylene allyl methyl ether (average degree of polymerization of ethylene oxide m = 9) (2) Monomer (c ¹ ) 13.0 parts by weight of acrylic acid (3) Monomer (c ² ) Methacrylic acid 36.2 parts by weight The molar ratio of polyoxyethylene allyl methyl ether, acrylic acid and methacrylic acid is 70, 9, 21.
The weight average molecular weight of the copolymer (B-1) obtained above was 1
5,000 (by GPC analysis).

Reference Example 7 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. (1) Monomer (b) Polyoxyethylene allyl isopropyl ether 325.2 parts by weight (average degree of polymerization of ethylene oxide n = 3) (2) Monomer (c ¹ ) 13.0 parts by weight acrylic acid (3) Monomer (c ² ) Methacrylic acid 36.2 parts by weight The molar ratio of polyoxyethylene allyl isopropyl ether, acrylic acid and methacrylic acid is 70, 9, 21. The weight average molecular weight of the copolymer (C-1) obtained above was 25,000 (by GPC analysis).

Example 6 An aqueous solution containing 12.1% by weight of the copolymer (B-1) obtained in Reference Example 6 and 12.9% by weight of the copolymer (C-1) obtained in Reference Example 7 was prepared. The mixture was evaluated in the same manner as in Example 1 except that this was used as a cement admixture. Table 2 shows the results.

[0032]

[Table 2] * Weight% of solid content of admixture to cement

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) // C04B 103: 32 F term (Reference) 4J100 AB07S AG08P AG08Q AG15P AG15Q AH27S AJ02R AK03R AK07R AK08R AL08P AL08S AM21S BA04P BA04Q BA05P BA05Q BA06P BA06Q BA08P BA08Q BA56S CA06 DA01

Claims (5)

[Claims] 1. A monomer (a) represented by the following general formula (1): 10 to 80 mol%; a monomer (b) represented by the following general formula (2): 5 to 70 mol%; (3)
A cement admixture comprising a copolymer (A) containing 5 to 70 mol% of a monomer (c) represented by the following formula and 0 to 50 mol% of a sulfonic acid group-containing monomer (d). General formula (1): (Wherein, R ¹ represents hydrogen or a methyl group, R ² represents hydrogen or an alkyl group having 1 to 3 carbon atoms, X represents O, CH ₂ O or COO, and m represents an average degree of polymerization of 6 to 6. (Shows the number of 100) General formula (2): (Wherein, R ³ represents hydrogen or a methyl group, and R ⁴ has 1 carbon atom.
Indicates 24 aliphatic group, Y represents O or CH ₂ O,
AO represents a single or mixed oxyalkylene group having 2 to 4 carbon atoms, n represents an average degree of polymerization, and R ⁴ has 1 to 3 carbon atoms.
Represents the number of 1 to 5, and the carbon number of R ⁴ is ⁴ to 24.
In the case of, it represents the number of 2 to 30) General formula (3): (Wherein, R ⁵ represents hydrogen or a methyl group, and M represents hydrogen or a salt-forming cation) 2. A monomer (a) represented by the following general formula (1): 20 to 90 mol%, a monomer (c) represented by the following general formula (3): 5 to 70 mol%, and a sulfonic acid group-containing monomer (D) Copolymer (B) 3 containing 0 to 50 mol%
0 to 90% by weight, 10 to 90 mol% of a monomer (b) represented by the following general formula (2), 5 to 70 mol% of a monomer (c) represented by the following general formula (3), and a sulfonic acid group Copolymer (C) containing 0 to 50 mol% of monomer (d)
A cement admixture comprising 10 to 70% by weight. General formula (1): (Wherein, R ¹ represents hydrogen or a methyl group, R ² represents hydrogen or an alkyl group having 1 to 3 carbon atoms, X represents O, CH ₂ O or COO, and m represents an average degree of polymerization of 6 to 6. General formula (2): (Wherein, R ³ represents hydrogen or a methyl group, and R ⁴ has 1 carbon atom.
Indicates 24 aliphatic group, Y represents O or CH ₂ O,
AO represents a single or mixed oxyalkylene group having 2 to 4 carbon atoms, n represents an average degree of polymerization, and R ⁴ has 1 to 3 carbon atoms.
Represents the number of 1 to 5, and the carbon number of R ⁴ is ⁴ to 24.
In the case of, it represents a number of 2 to 30) General formula (3): (Wherein, R ⁵ represents hydrogen or a methyl group, and M represents hydrogen or a salt-forming cation) 3. The monomer (c) comprises a monomer (c ¹ ) composed of methacrylic acid or a salt thereof and a monomer (c ² ) composed of acrylic acid or a salt thereof, wherein the monomer (c ¹ ) and the monomer (c ² ) ) And [c ¹ ] / [c ² ]
Is from 98/2 to 50/50. 4. The monomer (c) comprises a monomer (c ¹ ) composed of methacrylic acid or a salt thereof and a monomer (c ² ) composed of acrylic acid or a salt thereof, wherein the monomer (c ¹ ) and the monomer (c ² ) ) And [c ¹ ] / [c ² ]
Is from 98/2 to 50/50. 5. A cement composition comprising the cement admixture according to any one of claims 1 to 4.