JPH05238796A - Cement admixture and production of concrete by using this admixture - Google Patents

Abstract

PURPOSE:To provide the cement admixture effective for improving the dispersibility, suppressing a slump loss and improving strength and durability to a cement compsn, by consisting this admixture of a copolymer of a polyalkylene glycol diester monomer having an unsatd. bond and an acrylic acid-based monomer and/or the metal salt thereof. CONSTITUTION:This cement admixture consists of the copolymer of (1) the polyalkylene glycol diester monomer having the unsatd. bond and (2) the acrylic acid-based monomer and/or the metal salt of this copolymer. The monomer (1) is exemplified by the monomer of formula I and the monomer (2) is exemplified by the monomers of formulas II and III. In the formulas I to III, R<1>, R<2>, R<3>, R<4> denote hydrogen, methyl group, (CH2)m3COOM<1>, etc.; AO denotes 2 to 3C oxyalkylene group; m1-3 denote an integer from 0 to 2; n1 denotes an integer from 3 to 500; M<1> denotes hydrogen, univalent metal, amino group, etc.; R<5> R<6> denote hydrogen, methyl group; X<1> denotes a univalent metal, ammonium group, amino group, etc.; X<2> denotes a bivalent metal.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a cement admixture, and more specifically to a cement composition, such as cement paste, mortar and concrete, for improving dispersibility, suppressing slump loss, and improving strength and durability. The present invention relates to an intended cement admixture and a method for producing concrete using the same.

[0002]

BACKGROUND OF THE INVENTION Various cement admixtures are known, and a typical one is a β-naphthalenesulfonic acid formaldehyde condensate (hereinafter referred to as β-NSF). (Abbreviated) salt, melamine sulfonic acid formaldehyde condensate salt, oxycarboxylic acid salt, polycarboxylic acid salt, ligninsulfonic acid (hereinafter L
A salt (abbreviated as S) is known. These are used when kneading a cement composition, and the amount of water used is reduced and the workability is improved by this. However, it is known that all of these known dispersants have a significant decrease in fluidity over time (hereinafter referred to as slump loss) as a common drawback.

Generally, in a hydraulic cement composition, the chemical and physical agglomeration of cement particles progresses with the lapse of time after mixing, and the fluidity is gradually lost, causing a problem in workability in construction. In particular, concrete containing a high-performance water reducing agent represented by β-NSF is used when an admixture for concrete is not used, or when an AE (air entrainment) agent, water reducing agent, AE
The slump loss is remarkable due to the high water reduction rate as compared with the case of using the conventional admixture such as the water reducing agent.

When such a slump loss occurs, for example, when pumping the cement composition in a concrete secondary product (pile, pole, fume pipe, etc.) factory, the pumping is temporarily interrupted due to a trouble or the like. ,
After that, when the pumping is restarted, the pumping pressure suddenly increases,
An accident such as a blockage of the pump will occur. Further, if the molding such as compaction is delayed for some reason after the cement composition is driven into the mold, problems such as unfilling occur.

Also with regard to ready-mixed concrete, slump loss occurs during the period in which it is transported from the concrete manufacturing plant to the pouring site by the agitator vehicle (green concrete mixer vehicle), workability is significantly deteriorated, pump is blocked, and at the time of construction. This may cause problems such as unfilling.

Although the cause of such slump loss has not been clarified, after the cement particles in the cement paste come into contact with water, agglomeration due to a chemical hydration reaction and / or physical attraction due to an attractive force between particles occur. It is speculated that the aggregation progresses and the fluidity of the cement paste and thus the hydraulic cement composition decreases with time. Therefore, if the water reducing agent that disperses the cement particles can be continuously supplied by some method, the cement particles can always be dispersed in the form of primary particles, and slump loss of the hydraulic cement composition can be prevented. It is thought to be possible.

As a method found as a countermeasure against slump loss based on such an idea, there is the following method. (1) A method of adding a setting retarder such as oxycarboxylate or lignin sulfonate for the purpose of preventing chemical agglomeration of cement [cement concrete 430 , 30 (198
2)]. (2) A method for preventing physical agglomeration of cement particles by adding a high-performance water reducing agent or a fluidizing agent in a granular form [Cement Concrete 433 , 10 (1984)]. (3) A method of maintaining fluidity by stabilizing air bubbles by adding a dispersant having high air entrainment to an ordinary dispersant [Cement Technical Report 33 , 433 (1979)].

However, in the above method (1), the chemical aggregation of cement particles is suppressed to some extent, but the effect is not sufficient. Further, if the amount of addition is increased to enhance the effect, the initial slump becomes too large, and there is a risk of causing aggregate separation, and it also causes an increase in setting time, which is a major obstacle to breathing and initial strength. Further above (2)
Although the slump loss prevention effect is sufficiently recognized even in the method of, the cement dispersant remains locally in the cement mixture even after the purpose of maintaining the slump is terminated, and local breathing occurs, and eventually the strength is reduced. Leave the adverse effects such as. Further, also in the above method (3), the flow effect of bubbles is limited, and sufficient slump retention is not obtained.

A method for suppressing slump loss by introducing an alkylene group or a polyalkylene group into the molecular structure of an admixture and forming a graft structure when adsorbed to cement (Japanese Patent Laid-Open No. 3-93660, Japanese Patent Publication No. No. 2-11542 and Japanese Patent Publication No. 2-7901) have been proposed. However, steric repulsion due to these graft structures is not sufficient to completely suppress slump loss.

Further, a method of introducing a cross-linking structure by an alkyl group or a polyalkylene group or a branched structure by an ester group into the molecular structure of the admixture (JP-A-2-281014) has been proposed. Since it has a hydrophobic group (ester group), a large amount of air is likely to be entrained during concrete kneading, which adversely affects the physical properties (strength) after curing.

On the other hand, these known dispersants have some problems in terms of strength and durability. In terms of strength, there is a problem that a large amount of floating water (breathing) is generated after concrete construction. When a large amount of breathing occurs, the water passage generated when the water in the concrete appears on the surface impairs the denseness of the concrete structure and causes a decrease in strength during hardening. Breathing is a kind of separation phenomenon caused by the difference in specific gravity between water in concrete and other components (aggregate, cement). Since there are various causes of breathing, there are currently no radical measures. As a method of suppressing breathing, generally, a method of increasing the viscosity of the paste by using a fine powder or using a thickening agent and increasing the separation resistance is adopted. It is problematic and not an effective means.

Further, in terms of durability, there is a problem that the amount of bubbles in concrete decreases with time. Bubbles in concrete are known to relieve the internal pressure associated with the volume expansion of water due to freezing in winter. Therefore, usually, about 3 to 5% of fine bubbles are mixed. If this amount is small, the internal pressure relaxing effect at the time of freezing will be reduced, and conversely if it is large, the strength will decrease due to the decrease in the density of the concrete structure, affecting the durability of the concrete. For the adjustment of bubbles, generally, an AE (air entrainment) agent and an antifoaming agent are used together with a dispersant to control the size and amount of bubbles. However, in such a method, since the amounts of the AE agent and the defoaming agent added differ depending on the conditions, there is a problem in workability.

[0013]

Means for Solving the Problems In consideration of the above problems, the present inventors have studied a slump loss preventing method and a method for improving strength and durability by using a conventional admixture for concrete, The present invention has been completed. That is, the present invention is a cement admixture characterized by comprising a copolymer obtained by polymerizing the monomers shown in (1) and (2) below, and / or a metal salt of the copolymer. It is about. (1) Polyalkylene glycol diester-based monomer having an unsaturated bond (2) Acrylic acid-based monomer Also, the present invention, the above (1), (2) monomer and the following
(3) A cement admixture characterized by comprising a copolymer obtained by polymerizing the monomer shown in (3) and / or a metal salt of the copolymer.

(3) Polyalkylene glycol monoester-based monomer having unsaturated bond Further, the present invention provides one kind selected from the group of cement admixtures described above and a naphthalenesulfonic acid formaldehyde condensate or a metal thereof. 1 selected from the group consisting of a salt, a melamine sulfonic acid formaldehyde condensate or a metal salt thereof, a lignin sulfonic acid or a metal salt thereof, an oxycarboxylic acid or a metal salt thereof, a water-insoluble polymer and a water-insoluble metal complex (complex salt compound). The present invention relates to a method for producing concrete, which is characterized in that it is used together with a cement admixture which is one kind or two or more kinds of compounds.

Examples of the polyalkylene glycol diester type monomer of the monomer (1) used in the present invention include compounds represented by the following general formula (a). General formula (a)

[0016]

[Chemical 7]

In the formula, R ¹ , R ² , R ³ , R ⁴ : hydrogen, methyl group, (CH ₂ ) _m3 COOM ¹ , [(CH ₂ ) _m4 COO]
₂ M ² , (CH ₂ ) _m5 CONH (AO) _n2 X ¹ ,

[0018]

[Chemical 8]

[0019] _{(CH 2) m7 COO (AO} ) n5 X 1 AO: oxyalkylene group having 2 to 3 carbon atoms M1 to M7: 0 to 2 integer n1 to n5: 3 to 500 integer M ^1: hydrogen, One Valent metal, ammonium group, amino group or substituted amino group M ² : divalent metal X ¹ : hydrogen, alkyl group having 1 to 3 carbon atoms, for example, triethylene glycol diacrylate (3E-DA), polyethylene glycol (# 200) Diacrylate (4E-D
A), polyethylene glycol (# 400) diacrylate (9E-DA), polyethylene glycol (# 600) diacrylate (14E-DA), polyethylene glycol (# 1000) diacrylate (23E-DA), polyethylene glycol (# 2000 ) Diacrylate (46E-DA), polyethylene glycol (# 4000) diacrylate (92E
-DA), polyethylene glycol (# 6000) diacrylate (138E-DA), triethylene glycol dimethacrylate (3E-DMA), polyethylene glycol (# 200) dimethacrylate (4E-DMA), polyethylene glycol (# 400) di Methacrylate (9E-DM
A), polyethylene glycol (# 600) dimethacrylate (14E-DMA), polyethylene glycol (# 1000) dimethacrylate (23E-DMA), polyethylene glycol (# 2000) dimethacrylate (46E-DMA), polyethylene glycol (# 4000 ) Dimethacrylate (92E-DM
A), polyethylene glycol diesters such as polyethylene glycol (# 6000) dimethacrylate (138E-DMA), polypropylene oxide diesters, and diesters of polyethylene glycol / polypropylene oxide copolymers. Further, since the reactivity decreases as the number of moles of alkylene glycol added increases, polyalkylene glycol diesters having a number of moles of addition of 500 or less are preferred.

Examples of the acid having an unsaturated bond in synthesizing the polyalkylene glycol diester include monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid; maleic acid, fumaric acid, itaconic acid, citraconic acid and the like. Dicarboxylic acids and their derivatives (unsaturated amides, etc.)
Examples include sulfonic acid systems such as vinyl sulfonic acid, allyl sulfonic acid, sulfoethyl (meth) acrylic acid, and styrene sulfonic acid, and one or more selected from these groups can be used. Carboxylic acid type, dicarboxylic acid and its derivative type are more preferable.

Examples of the acrylic acid type monomer of the monomer (2) used in the present invention include compounds represented by the following general formulas (b) and (c). General formula (b)

[0022]

[Chemical 9]

General formula (c)

[0024]

[Chemical 10]

R ⁵ , R ⁶ : hydrogen, methyl group X ¹ : monovalent metal, ammonium group, amino group or substituted amino group X ² : divalent metal such as acrylic acid metal salt, methacrylic acid metal salt, and crotonic acid metal One or more kinds of monomers selected from the group consisting of salts and the like can be mentioned, and monovalent metal salts thereof are particularly preferable.

The proportion (% by weight) of the monomers (1) and (2) in the copolymer of the present invention is preferably in the range of (1) :( 2) = 1-95: 99-5. And more preferably (1) :( 2) = 1 to 70:
A range of 99 to 30 is good. When the proportion of the monomer (1) is less than 1% by weight, a sufficient slump loss suppressing effect is not exhibited.
On the other hand, if the proportion of the monomer (2) is less than 5% by weight, sufficient dispersibility cannot be obtained. The weight average molecular weight of the copolymer of the present invention (sodium polystyrene sulfonate standard, gel permeation chromatography method) is 1,000 to 1,000,0
The range of 00 is good, and more preferably 2,000 to 500,000. When the weight average molecular weight is 1,000 or less, the dispersibility is insufficient, while when it is 1,000,000 or more, the cohesiveness becomes remarkable, which is not preferable.

In producing the copolymer of the present invention, it is possible to copolymerize with a monomer other than the monomers (1) and (2). Examples of the copolymerizable monomer include compounds represented by the general formula (d):

[0028]

[Chemical 11]

R ⁷ , R ⁸ : hydrogen, methyl group, (CH ₂ ) _m9
COOM ¹ , [(CH ₂ ) _m10 COO] ₂ M ² , (CH ₂ ).
_m11 CONH (AO) _n7 X ³ ,

[0030]

[Chemical 12]

[0031] _{(CH 2) m13 COO (AO} ) n10 X 3 AO: oxyalkylene group having 2 to 3 carbon atoms m8~m13: 0~2 integer n6~n10: 3~500 integer M ^1: hydrogen, One valent metal, an ammonium group, an amino group or a substituted amino group M ^2: divalent metal X ^2, X ^3: a hydrogen, an alkyl group having 1 to 3 carbon atoms, triethylene glycol monoacrylate (3E
-A), polyethylene glycol (# 200) monoacrylate (4E -A), polyethylene glycol (# 400) monoacrylate (9E -A), polyethylene glycol (# 600) monoacrylate (14E -A), polyethylene glycol (# 1000) Monoacrylate (23E-A), Polyethylene glycol (# 2000) Monoacrylate (46
E-A), polyethylene glycol (# 4000) monoacrylate (92E-A), polyethylene glycol (# 6000)
Monoacrylate (138E-A), triethylene glycol monomethacrylate (3E-MA), polyethylene glycol (# 200) monomethacrylate (4E-MA)
Polyethylene glycol (# 400) monomethacrylate (9E-MA), polyethylene glycol (# 600) monomethacrylate (14E-MA), polyethylene glycol (# 1000) monomethacrylate (23E-MA), polyethylene glycol (# 2000) mono Methacrylate (46E-MA)
, Polyethylene glycol (# 4000) monomethacrylate (92E-MA), polyethylene glycol (# 6000) monomethacrylate (138E-MA) and other polyethylene glycol monoesters, polypropylene oxide monoesters, polyethylene glycol / polypropylene oxide copolymer Examples of the monoesters and their derivatives obtained by etherifying the hydrogen at the glycol terminal include polyalkylene glycols having an addition mole number of 500 or less because the reactivity decreases as the addition mole number of alkylene glycol increases. Monoesters and their glycol-terminated hydrogen-etherified derivatives are preferred.

As the acid having an unsaturated bond at the time of synthesizing the polyalkylene glycol monoester, carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid;
Dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid and citraconic acid and their derivatives (unsaturated amides); sulfonic acid types such as vinyl sulfonic acid, allyl sulfonic acid, sulfoethyl (meth) acrylic acid and styrene sulfonic acid One or more selected from these groups can be used, but monocarboxylic acid type, dicarboxylic acid and its derivative type are more preferable.

As copolymerizable monomers other than polyalkylene glycol monoesters, maleic anhydride,
Maleic acid, itaconic anhydride, itaconic acid, citraconic anhydride, citraconic acid, fumaric acid and its metal salts, ammonium salts, organic amine salts or these acids and 2 to 2 carbon atoms
Monoesters or diesters of 3 with polyalkylene glycol (glycol addition mole number: 2 to 500); vinyl sulfonic acid, allyl sulfonic acid, sulfoethyl (meth) acrylate, styrene sulfonic acid and its metal salts, ammonium salts, organic One or more monomers selected from the group consisting of unsaturated sulfonic acids such as amine salts may be mentioned.

The copolymer of the present invention can be produced by polymerizing the monomers (1) and (2) with a polymerization initiator. The polymerization can be carried out by a method such as polymerization in a solvent or bulk polymerization. The synthesis in the solvent can be carried out batchwise or continuously. Examples of the solvent include water, lower alcohols, aromatic hydrocarbons, aliphatic hydrocarbons and ketone compounds, and particularly water, methyl alcohol, ethyl alcohol, isopropyl alcohol and water / lower alcohol mixed systems from the viewpoint of workability. preferable. As the polymerization initiator when the polymerization is carried out in an aqueous system, ammonium or alkali metal persulfate, hydrogen peroxide and the like are suitable. Polymerization temperature is 0
~ 120 ℃ is good.

As the polymerization initiator for bulk polymerization, peroxides such as benzoyl peroxide and aliphatic azo compounds such as azobisisobutyronitrile are preferable. The polymerization temperature is preferably 40 ° C to 160 ° C. The reason why the admixture of the present invention exhibits excellent dispersibility and slump loss suppressing effect is not only the electrostatic repulsion force due to the monomer (2) but also the introduction of a crosslinked structure due to the monomer (1). It is considered that this is because a loop structure is easily formed when adsorbed on the cement surface, and as a result, higher steric repulsion force is exhibited. In this respect, Japanese Patent Publication No. 2-11542, which aims at suppressing the slump loss by utilizing the steric repulsive force only by the graft structure,
It is clearly different from Japanese Patent Publication No. 2-7898 and Japanese Patent Publication No. 2-8983.

The product of the present invention has an excellent slump loss suppressing effect by itself, but it is a water-insoluble polymer and a water-insoluble metal complex (complex salt compound) (for example, JP-B-63-53).
46, JP-A-62-83344, JP-A-1-270550
The effect is improved by using it together. In addition, the reason why the present invention has an excellent breathing suppressing effect and bubble stability is that water retention by alkylene glycol and air by increasing the ratio of hydrophilic group / (hydrophilic group + hydrophobic group) in the molecule. It is thought that this is due to the reduction in the entrainment. In this respect, it is apparently different from the fluidity deterioration preventing agent described in JP-A-2-281014, which has an ester bond in the molecule. The copolymer of the present invention alone has an excellent effect of suppressing breathing and bubble stability, but these effects are further enhanced by using it in combination with polyalkylene glycol.

The copolymer produced in the present invention can be used as a dispersant even if it is an acid, but it is generally preferable to use it in the form of a salt. Examples of the cation to be formed include sodium, potassium, calcium, ammonium, alkanolamine, N-alkyl-substituted polyamine, ethylenediamine, polyethylenepolyamine and the like. When the copolymer of the present invention is used as a concrete dispersant, the addition amount is preferably 0.005% to 2.5% as a solid content% by weight relative to the cement in the cement mixture. 0.005% by weight
If it is less than the above range, a sufficient dispersing effect for the cement particles cannot be obtained. On the other hand, if it exceeds 2.5% by weight, it is economically disadvantageous, excessive dispersion of cement particles causes bleeding or paste separation, and increases the setting time to lower the initial strength.

The method for adding the copolymer of the present invention to the cement composition can be an aqueous solution or powder, and the addition timing is dry blending with cement, dissolution in kneading water,
Alternatively, it can be added at the start of kneading of the cement mixture, that is, at the same time as pouring water into the cement or immediately after pouring water until the end of kneading of the cement mixture, and can be added to the cement mixture once kneaded. is there. It is also possible to add the entire amount at once or to add it in several divided portions. When a known dispersant is used in combination, naphthalenesulfonic acid formaldehyde condensate or a salt thereof, alkylnaphthalenesulfonic acid formaldehyde condensate or a salt thereof, ligninsulfonic acid or a salt thereof, melaminesulfonic acid formaldehyde condensate or a salt thereof, oxycarboxylic acid Acid or a salt thereof, polycarboxylic acid or a salt thereof, and polyalkylene carboxylic anhydride or a salt thereof (for example, Japanese Patent Publication No.
-5346, JP 62-83344, JP 1-27
No. 0550)) or the like, or after mixing one with the cement or the cement mixture, or one with the cement or the cement mixture and kneading before mixing the other. May be.

Further, other cement additives (materials) such as sustained-release dispersant, AE (air entrainment) water reducing agent, superplasticizer, high-performance water reducing agent, retarder, early strengthening agent, accelerator, foaming agent. Agents, foaming agents, defoamers, water retention agents, thickeners, self-leveling agents, waterproofing agents, rust preventives, coloring agents, anti-mold agents, crack reducing agents, polymer emulsions, other surfactants, high water solubility It is also possible to use it in combination with a molecule, a swelling agent (material), and glass fiber. The weight average molecular weight of the cement dispersant used in the present invention is a value measured by gel permeation chromatography using polystyrene sulfonate sodium salt as a reference substance.

[0040]

EFFECTS OF THE INVENTION Since the present invention makes it possible to maintain the workability of concrete for a long time, the cement dispersant according to the present invention is specifically used for various purposes. For example, it is used as a pumping aid for concrete. Cement compounds are often placed by pumping, but as mentioned above, during work lunch breaks,
When the pump pumping is temporarily interrupted due to setup change or mechanical failure, the workability of the concrete in the pumping pipe decreases if the suspension time is extended, and the pumping pressure when pumping is restarted suddenly rises or is blocked. Is occurring.
However, when the cement dispersant according to the present invention is added, the workability of the concrete is kept constant, the deterioration of the fluidity is prevented, and it is possible to prevent the increase of the pressure when the pumping is restarted after the pumping is stopped. Therefore, it is possible to significantly enhance the effect of the pumping work. Still other examples are auxiliaries for grout of cement milk or mortar, cement mixes cast by tremie pipes, underwater concrete, concrete for continuous underground walls, sprayed concrete, centrifugally molded concrete, vibration compacted concrete, etc. It is also effective for applications such as maintaining fluidity and preventing material separation. Further, the present invention maintains the compactness of concrete because it has an excellent breathing suppression effect and bubble stability, and furthermore, the physical properties after hardening of concrete by controlling the amount of air in the concrete to be constant, particularly strength and It can be expected to improve durability.

[0041]

EXAMPLES The present invention will be described below with reference to production examples and examples of the present invention, but the present invention is not limited to these examples. All parts in the production examples are parts by weight. Production Example (1) 285 parts of water was charged into a reaction vessel equipped with a stirrer, and nitrogen substitution was performed while stirring, and the temperature was raised to 60 ° C in a nitrogen atmosphere. Polyethylene glycol dimethacrylate (9E-DMA) 40 parts, polyethylene glycol monomethacrylate (9E-MA) 10
And 50 parts of sodium methacrylate (MAA-Na) were charged, and the pH of the solution was adjusted to 9.5 with 2 parts of 30% aqueous sodium hydroxide solution.
Adjusted to. After substituting with nitrogen, 10 parts of a 20% aqueous solution of ammonium persulfate was added to initiate polymerization, and the reaction was allowed to proceed for 6 hours to complete the polymerization reaction. Completely neutralized with 3 parts of 30% aqueous sodium hydroxide solution to obtain a copolymer. The contents of the copolymer of the present invention produced according to Production Example (1) are shown in Table 1 below.

[0042]

[Table 1]

Production Example (8) Isopropyl alcohol (hereinafter
(Abbreviated as IPA) 265 parts were charged, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to the boiling point in a nitrogen atmosphere. Charge 30 parts of polyethylene glycol diacrylate (138E-DA), 20 parts of polyethylene glycol monoacrylate (138E-A), 50 parts of sodium acrylate (AA-Na), and adjust the pH of the solution with 2 parts of 30% sodium hydroxide aqueous solution. Adjusted to 8.5. After substituting with nitrogen, 30 parts of a 10% IPA solution of benzoyl peroxide was added to start polymerization, and the reaction was allowed to proceed for 6 hours to complete the polymerization reaction. Completely neutralize with 3 parts of 30% sodium hydroxide solution,
A copolymer was obtained. Table 2 below shows the contents of the copolymer of the present invention produced according to Production Example (8).

[0044]

[Table 2]

Production Example (14) 50 parts of water and 70 parts of IPA were charged into a reaction vessel equipped with a stirrer,
The atmosphere was replaced with nitrogen while stirring, and the temperature was raised to the boiling point in a nitrogen atmosphere. Polyethylene glycol dimethacrylate (23E-
DMA) 30 parts, polyethylene glycol monoacrylate (46E-A) 20 parts, sodium acrylate (AA-Na) 50 parts were charged, and the pH of the solution was adjusted with 1 part of 30% sodium hydroxide aqueous solution.
Was adjusted to 7.6. After replacing with nitrogen,
25 parts of 10% aqueous solution was added to initiate polymerization, and the reaction was continued for 4 hours.
The polymerization reaction was completed. Completely neutralized with 4 parts of 30% aqueous sodium hydroxide solution to obtain a copolymer. Table 3 below shows the content of the copolymer of the present invention produced according to Production Example (14).

[0046]

[Table 3]

Production Example (17) In a reaction vessel equipped with a stirrer, 135 parts of water was charged, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 90 ° C. in a nitrogen atmosphere. Polyethylene glycol diacrylate (14E-DA) 40 parts, methoxy polyethylene glycol (# 400) monomethacrylate (9ME-MA) 20 parts, sodium acrylate (AA-Na) 20
Part, 20 parts of sodium maleate (M-Na) was charged, 30 parts
The pH of the solution was adjusted to 9.5 with 2 parts of aqueous sodium hydroxide solution. After replacing with nitrogen, 20% aqueous solution of ammonium persulfate 10
Part of the mixture was added to start polymerization, and the reaction was continued for 4 hours to complete the polymerization reaction. Completely neutralized with 3 parts of 30% aqueous sodium hydroxide solution to obtain a copolymer. Table 4 below shows the contents of the copolymer of the present invention produced according to Production Example (17).

[0048]

[Table 4]

Production Example (22) In a reaction vessel equipped with a stirrer, 135 parts of water was charged, the atmosphere was replaced with nitrogen while stirring, and the temperature was raised to 90 ° C in a nitrogen atmosphere. Polyethylene glycol diacrylate (23E-DA) 10 parts, methoxy polyethylene glycol (# 1000) monomethacrylate (23ME-MA) 20 parts, sodium methacrylate (MAA
-Na) 40 parts and sodium maleate (M-Na) 30 parts, and adjust the pH of the solution with 2 parts of 30% sodium hydroxide aqueous solution.
Adjusted to 9.5. After replacing with nitrogen, ammonium persulfate 20
% Aqueous solution (10 parts) was added to initiate polymerization and the reaction was continued for 4 hours to complete the polymerization reaction. Completely neutralized with 3 parts of 30% aqueous sodium hydroxide solution to obtain a copolymer. Table 5 below shows the contents of the copolymer of the present invention produced according to Production Example (22).

[0050]

[Table 5]

Evaluation as Cement Admixture (1) Mixing of concrete was carried out as follows. Usage W / C (%) S / A, (%) C, (Kg / m ³ ) (I) General strength 60 S ₁ / A ₁ = 49 300 (II) High strength 20 S ₂ / A ₂ = 43 750 where C is cement, W is water, S ₁ and S ₂ are fine aggregates, and A ₁ and A ₂ are all aggregates (total volume of fine aggregates + coarse aggregates G). Shown respectively.

(2) The materials used are shown below. Cement (C): Normal Portland cement (specific gravity 3.1
7) Fine aggregate (S ₁ ): Sand from Setouchi (specific gravity 2.52, FM2.82) Fine aggregate (S ₂ ): Sand from Kinokawa (specific gravity 2.58, FM2.91) Coarse aggregate (G): Crushed stone from Takarazuka (Specific gravity 2.61, FM6.98) (3) Mixing method of concrete Mix cement dispersant in advance and dissolve in water,
50 liters of concrete was kneaded for 3 minutes using a 00 liter tilting mixer and then rotated 4 times per minute to measure the slump and the air amount over time. JIS slump test
The A1101 and air amount tests were performed according to JIS A 1128. In addition, a breathing test (based on JIS A 1123) was performed in parallel. After hardening the concrete, a compressive strength test was conducted in accordance with JIS A 1108. (I) General strength combination Tables 6 and 7 show the obtained evaluation results.

[0053]

[Table 6]

[0054]

[Table 7]

The addition amount of the admixture is 0.4% solid content.
(% By weight of cement) -The compounding ratio (weight ratio) of the admixture is:
Blend ratio of B and C a) 0.02% of solid content of copolymer of isobutylene and maleic anhydride (molar ratio 1: 1) (% by weight of cement)
To the admixture. b) A zinc complex (complex salt compound) of a copolymer of isobutylene and maleic anhydride (molar ratio 1: 1) was added to the admixture so that the solid content was 0.02% (based on the weight of cement). c) Polyethylene glycol (# 1000) as solid content
It was added to the admixture so that it would be 0.3% (relative to cement weight%). A: Naphthalene-based dispersant [Product name Mighty 150,
Kao Co., Ltd.] B: Lignin-based dispersant [Brand name Ultragin N
A, manufactured by Boregard Co.] C: polycarboxylic acid type dispersant [polyacrylic acid sodium salt] D: copolymer of methoxypolyethylene glycol (# 1000) methacrylate (23ME-MA) and sodium methacrylate (weight ratio 30: 70, weight average molecular weight Mw7,000) E: 6-hexanediol diacrylate, polyethylene glycol (# 1000) acrylate (23E-A) and copolymer with ethyl methacrylate (weight ratio 30: 30: 4
0, weight average molecular weight Mw12,000) (II) High-strength compounding The obtained evaluation results are shown in Tables 8 and 9.

[0056]

[Table 8]

[0057]

[Table 9]

The amount of admixture added is 1.0% solids
(% By weight of cement) -The compounding ratio (weight ratio) of the admixture is:
Blend ratio of B and C a) 0.04% of solid content of copolymer of isobutylene and maleic anhydride (molar ratio 1: 1) (% by weight of cement)
To the admixture. b) A zinc complex (complex salt compound) of a copolymer of isobutylene and maleic anhydride (molar ratio 1: 1) was added to the admixture so that the solid content was 0.08% (based on the weight of cement). c) Polyethylene glycol (# 6000) as solid content
It was added to the admixture so that it would be 0.3% (relative to cement weight%). d) Addition amount: solid content 1.5% (relative to cement weight%) A: naphthalene-based dispersant [trade name Mighty 150,
Kao Corporation] B: Melamine-based dispersant [Product name: Melment, Showa Denko KK] C: Polycarboxylic acid-based dispersant [Polyacrylic acid sodium salt] D: Methoxypolyethylene glycol (# 1000) methacrylate ( 23ME-MA) and sodium methacrylate copolymer (weight ratio 50:50, weight average molecular weight Mw2,800) E: 6-hexanediol diacrylate, polyethylene glycol (# 6000) acrylate (138E-A) and methyl Copolymer with acrylate (weight ratio 30:50:20,
Weight average molecular weight Mw130,000) From the results of Table 6, Table 7, Table 8 and Table 9, the slump, the air content, and the compressive strength of the product of the present invention are higher than those of the comparative product in both the general strength composition and the high strength composition. It is excellent, and the breathing rate of general strength compound is smaller than the comparative product,
It can be seen that the suppression of breathing is good.

[Evaluation Results] The cement admixture according to the present invention has a wider range of water / cement (W / C) than conventional dispersants.
In the region C), excellent dispersibility, slump loss prevention effect, and breathing suppression effect are remarkably exhibited, and also in terms of bubble stability in concrete and concrete strength.

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[Procedure amendment]

[Submission date] March 13, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 2

[Correction method] Change

[Correction content]

[Chemical 1] In the formula, R ¹ , R ² , R ³ , and R ⁴ : hydrogen, a methyl group, (C
H ₂ ) _m3 COOM ¹ , [(CH ₂ ) _m4 COO] ₂ M ² , (CH ₂ ) _m5 CONH (AO) _n2 X ¹ ,

[Chemical 2] _{(CH 2) m7 COO (AO} ) n5 X 1 AO: oxyalkylene group having 2 to 3 carbon atoms M1 to M7: 0 to 2 integer n1 to n5: 3 to 500 integer M ^1: hydrogen, a monovalent metal, Ammonium group, amino group or substituted amino group M ² : divalent metal X ¹ : hydrogen, alkyl group having 1 to 3 carbon atoms, general formula (b)

[Chemical 3] General formula (c)

[Chemical 4] R ⁵ , R ⁶ : hydrogen, methyl group X ¹ : monovalent metal, ammonium group, amino group or substituted amino group X ² : divalent metal

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

[0016]

[Chemical 7]

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Claims (9)

[Claims] 1. A cement admixture characterized by comprising a copolymer obtained by polymerizing the monomers shown in the following (1) and (2) and / or a metal salt of the copolymer. .. (1) Polyalkylene glycol diester monomer having unsaturated bond (2) Acrylic acid monomer 2. The monomer (1) is represented by the following general formula (a):
The cement admixture according to claim 1, wherein (2) is at least one monomer selected from the group of monomers represented by the following general formulas (b) and (c). General formula (a) In the formula, R ¹ , R ² , R ³ , and R ⁴ : hydrogen, a methyl group, (C
H ₂ ) _m3 COOM ¹ , [(CH ₂ ) _m4 COO] ₂ M ² , (CH ₂ ) _m5 CONH (AO) _n2 X ¹ , embedded image _{(CH 2) m7 COO (AO} ) n5 X 1 AO: oxyalkylene group having 2 to 3 carbon atoms M1 to M7: 0 to 2 integer n1 to n5: 3 to 500 integer M ^1: hydrogen, a monovalent metal, Ammonium group, amino group or substituted amino group M ² : divalent metal X ¹ : hydrogen, alkyl group having 1 to 3 carbon atoms, general formula (b): General formula (c) R ⁵ , R ⁶ : hydrogen, methyl group X ¹ : monovalent metal, ammonium group, amino group or substituted amino group X ² : divalent metal 3. A copolymer obtained by polymerizing the monomers (1) and (2) according to claim 1 and the monomer shown in the following (3) and / or the copolymer. A cement admixture characterized by comprising a metal salt of (3) Polyalkylene glycol monoester monomer having an unsaturated bond 4. The cement admixture according to claim 3, wherein the monomer (3) is at least one monomer selected from the group of monomers represented by the following general formula (d). General formula (d) R ^7, R ^8: hydrogen, methyl, (CH _{2) m9} COO
M ¹ , [(CH ₂ ) _m10 COO] ₂ M ² , (CH ₂ ) _m11 CONH (AO) _n7 X ³ , _{embedded image (CH 2) m13 COO (AO} ) n10 X 3 AO: oxyalkylene group having 2 to 3 carbon atoms m8~m13: 0~2 integer n6~n10: 3~500 integer M ^1: hydrogen, a monovalent metal, ammonium group, an amino group or a substituted amino group M ^2: divalent metal X ^2, X ^3: a hydrogen, an alkyl group having 1 to 3 carbon atoms 5. The monomer of (1) or (2) according to claim 1,
A cement admixture comprising a copolymer obtained by polymerizing a monomer copolymerizable with these monomers and / or a metal salt of the copolymer. 6. (1), (2) and claim 3 according to claim 1.
It is characterized by comprising the monomer (3) described above, a copolymer obtained by polymerizing a monomer copolymerizable with these monomers, and / or a metal salt of the copolymer. Cement admixture. 7. A copolymer obtained by polymerizing the monomers (1) and (2) according to claim 1 and a monomer copolymerizable with these monomers, and / or the copolymerization weight thereof. A cement admixture characterized by using a combined metal salt and a polyalkylene glycol together. 8. A method for producing concrete, characterized in that the cement admixture according to any one of claims 1 to 7 is used in combination with another cement admixture. 9. The cement admixture used in combination is a naphthalene sulfonic acid formaldehyde condensate or a metal salt thereof, a melamine sulfonic acid formaldehyde condensate or a metal salt thereof, a lignin sulfonic acid or a metal salt thereof, an oxycarboxylic acid or a metal salt thereof, and water. The method for producing concrete according to claim 8, which is one or more compounds selected from the group consisting of an insoluble polymer and a water-insoluble metal complex (complex salt compound).