JP2002167257A - Cement dispersant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cement dispersant preventing slump loss at high temperature while keeping high fluidity at filling. SOLUTION: The cement dispersant obtained by copolymerizing the specific polymer (A1) such as an ethylenic unsaturated carboxylic acid derivative having polyoxyalkylene group and the specific polymer (A2) such as (meth)acrylic acid, contains at least one compound selected from a group consisting of a copolymer mixture, the mole ratio (A1)/(A2) of which is changed at least one time in the middle of reaction, a salt of the copolymer mixture obtained by neutralizing by alkali, oxycarboxylic acid or its salt, saccharides and suger- alcohol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a cement dispersant.

[0002]

2. Description of the Related Art As a cement dispersant, a copolymer prepared from a polyalkylene glycol mono (meth) acrylate monomer and a (meth) acrylic monomer (hereinafter referred to as acrylic acid). It has been known. In this type of copolymer, alkylene oxide (hereinafter referred to as AO)
It is disclosed that characteristic performance can be imparted by changing the number of added moles (hereinafter referred to as n) and the monomer ratio (Japanese Patent Application Laid-Open No. 58-74552; Kaihei 8-12396). Such AO-added polycarboxylic acid-based cement dispersant is compared with a conventionally used naphthalene-based or melamine-based cement dispersant in terms of cement dispersibility, fluidity of a cement composition in a fresh state, material Excellent in separation resistance and curing strength development. Furthermore, in the industry, studies are underway to improve the performance of the AO-added polycarboxylic acid-based cement dispersant, such as high pumping performance and versatility corresponding to diversification of production conditions. It has been found that these performances can be improved by adjusting the copolymerization ratio (Japanese Patent Application No. 11-3).
61108).

[0003]

However, there is a demand for further improvement in the ability to prevent a decrease in fluidity with time (slump loss) at high temperatures where the concrete temperature exceeds about 30 ° C. In particular, slump loss at high temperatures is extremely large in systems that need to maintain high fluidity even during filling, such as general ready-mixed concrete, ready-mixed concrete, and high-fluidity concrete, which has become very popular through concrete products. It becomes a problem.

An object of the present invention is to have versatility for diversification of manufacturing conditions, etc., and to maintain high fluidity at the time of filling.
Another object of the present invention is to provide a cement dispersant capable of preventing slump loss at high temperatures.

[0005]

According to the present invention, there is provided a compound represented by the following general formula:
Obtained by copolymerizing at least one of the monomers represented by (a1) (A1) and at least one of the monomers represented by the following general formula (a2) (A2), and Molar ratio of monomers (A1) and (A2)
The copolymer mixture (A) wherein (A1) / (A2) is changed at least once in the course of the reaction or a copolymer mixture salt obtained by neutralizing the copolymer mixture with an alkali (hereinafter, both are copolymers) Mixture (A)] and one or more compounds (B) (hereinafter, referred to as component (B)) selected from the group consisting of oxycarboxylic acids or salts thereof, saccharides and sugar alcohols.

[0006]

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(Wherein, R ¹ , R ² : hydrogen atom or methyl group, m: the number of 0 to 2 R ³ : hydrogen atom or —COO (AO) _n X p: the number of 0 or 1, AO: the number of carbon atoms is 2) To 4 oxyalkylene group or oxystyrene group n: a number of 2 to 300 X: represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms.)

[0008]

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Wherein R ^{4 to} R ^{6 are a} hydrogen atom, a methyl group or (CH ₂ ) m ₁ COOM ² ;
(CH ₂ ) m ₁ COOM ² may form an anhydride with COOM ¹ or another (CH ₂ ) m ₁ COOM ² , in which case the groups M ¹ and M ² are absent. M ¹ , M ² : hydrogen atom, alkali metal, alkaline earth metal,
Ammonium group, alkyl ammonium group or substituted alkyl ammonium group m1: represents the number of 0 to 2. )

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION [Copolymer mixture (A)] As the monomer (A1) represented by the general formula (a1) used for producing the copolymer mixture (A), methoxypolyethylene glycol,
(Half) esterified product of (meth) acrylic acid and maleic acid with one-terminal alkyl-blocked polyalkylene glycol such as methoxypolypropylene glycol, methoxypolybutylene glycol, methoxypolystyrene glycol, ethoxypolyethylene polypropylene glycol,
Etherified products with (meth) allyl alcohol, and ethylene oxide and propylene oxide adducts to (meth) acrylic acid, maleic acid, and (meth) allyl alcohol are preferably used, R ₃ is preferably a hydrogen atom, and p is 1
However, m is preferably 0. More preferred are alkoxy, especially esterified products of methoxypolyethylene glycol and (meth) acrylic acid.

When the number of moles of AO added to the monomer (A1) represented by the general formula (a1) decreases, the curing speed, dispersibility, and viscosity tend to decrease, and when n increases, these increase. There is a tendency. Therefore, n may be selected according to the desired performance.

For example, when emphasis is placed on the initial strength development of concrete, it is preferable that 80 ≦ n, more preferably 90 ≦ n, further preferably 100 ≦ n, and most preferably 110 ≦ n. is there. When 300 <n, the dispersibility decreases and the polymerizability during the production decreases, so that n ≦ 200, more preferably n ≦ 150, and particularly preferably n ≦ 130.

When importance is placed on reducing the viscosity of concrete, 2 ≦ n ≦ 100 is preferable, and 5 ≦ n ≦ 8 is more preferable.
0, more preferably 5 ≦ n ≦ 50, most preferably 5 ≦ n
≦ 30.

When it is necessary to have both initial strength and viscosity reduction, it is preferable to copolymerize a polymer having a large n and a polymer having a small n. Particularly, as the monomer (A1), the following general formula (a1-1) ) Represented by the monomer (A1-1) and the following general formula (a1-2)
It is preferred to use together with the monomer (A1-2) represented by

[0015]

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Wherein R ^{a1 is a} hydrogen atom or a methyl group AO is an oxyalkylene or oxystyrene group having 2 to 4 carbon atoms, preferably an oxyalkylene group having 2 to 3 carbon atoms n _{1 is} a number of 12 to 300 X ^{1 represents a} hydrogen atom or an alkyl group having 1 to 18 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)

[0017]

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(Where R^a2: Hydrogen atom or methyl group AO: oxyalkylene group having 2 to 4 carbon atoms or oxysty
A rene group, preferably an oxyalkylene group having 2 to 3 carbon atoms n_Two: A number of 2 to 290 (however, n in the general formula (a1-1)₁Relationship with
The clerk is n₁> N_TwoAnd (n₁−n _Two) ≧ 10, preferably ≧ 30,
Is preferably ≧ 50. ) X^Two: A hydrogen atom or an alkyl group having 1 to 18 carbon atoms, preferably
Represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. ).

In this case, the average weight ratio of the two is preferably (A1-1) / (A1-2) = 0.1-8, more preferably 0.2-2.
5, particularly preferably in the range of 0.4 to 2. This average weight ratio is the average of the weight ratios of all monomers used in the reaction.

The reaction molar ratio of the monomers (A1-1), (A1-2) and (A2) [(A1-1) + (A1-2)] / (A2) is preferably ,
At least one of the molar ratios before and after the change is in the range of 0.02 to 4, more preferably 0.05 to 2.5, and particularly preferably 0.1 to 2. Most preferably, the molar ratio before and after the change are both in these ranges.

Under these conditions, 12 ≦ n ₁ ≦ 300, 2
≦ n ₂ ≦ 290, n ₂ + 10 ≦ n ₁ , more preferably n ₂ + 30 ≦ n ₁ , and even more preferably n ₂ + 50 ≦ n ₁ , the performance of both is remarkably exhibited. More preferably
80 ≦ n ₁ ≦ 300, ₂ ≦ n ₂ <50, more preferably 100 ≦ n ₁ ≦ 30
0, 2 ≦ n ₂ <30, particularly preferably 110 ≦ n ₁ ≦ 300, ₂ ≦ n ₂
It is to select n ₁ and n ₂ from <10.

The monomer (A2) represented by the general formula (a2) used in the production of the copolymer mixture (A) includes monocarboxylic acid-based monomers such as (meth) acrylic acid and crotonic acid. Monomer, maleic acid, itaconic acid, dicarboxylic acid monomers such as fumaric acid, or anhydrides or salts thereof, for example, alkali metal salts, alkaline earth metal salts, ammonium salts,
Mono, di, and trialkyl (C2-8) ammonium salts which may have a substituted hydroxyl group are preferred, more preferably (meth) acrylic acid, maleic acid and maleic anhydride, and still more preferably (meth) acrylic acid. Or their alkali metal salts.

The copolymer mixture (A) comprises the above monomer (A1),
(A2) is preferably reacted with (A1) / (A2) at a molar ratio in the range of 0.02 to 4, and these molar ratios (A1) / (A
2) is changed at least once during the reaction.
And, in the present invention, of the copolymer mixture (A), the average weight ratio of the monomer (A2) to all the monomers for producing the copolymer mixture (A-1) (X _I ) It is preferable to use the copolymer mixtures (A-2) obtained with different average weight ratios (X _II ) in combination. That is, the copolymer mixture (A-2) is obtained by reacting the monomers (A1) and (A2) with each other, preferably in a molar ratio of (A1) / (A2) = 0.02 to 4. The molar ratio (A1) / (A2) is changed at least once during the reaction, and the copolymer mixture (A-2)
The average weight ratio (X _II ) of the monomer (A2) to all the monomers for the production of is different from the average weight ratio (X _I ) of the copolymer mixture (A-1). The average weight ratio is represented by [total amount of monomer (A2) / total monomer amount] × 100 (% by weight), and is preferably in the range of 1 to 30 (% by weight). Hereinafter, this average weight ratio may be referred to as “(A2) average weight ratio”. The average weight ratios (X _I ) and (X _II ) are at least 1.0 (% by weight), further at least 2.0 (% by weight),
In particular, it is preferable that the difference is at least 3.0 (% by weight). Incidentally, the copolymer mixture (A-1) and (A-2), even if the type of the monomers (A1) and (A2) used in the production are different, in the present invention, the average weight ratio (X _I ) And (X _II ) should be different,
It is preferable to use the same type of monomers as (A1) and (A2).

In the present invention, the average ratio by weight of the copolymer mixture _{(A-1) (X I} ) is 1 to 30 wt%, further 7-20% by weight, it is preferable in particular 8 to 16 wt% . Then, when a blending system is assembled using the copolymer mixture (A-1) as a main component, a concrete water reducing agent having a well-balanced performance can be obtained.

In the present invention, the copolymer mixture (A-2)
As (A2), a plurality of copolymers each obtained from a plurality of monomer mixtures having different average weight ratios can be used. From a practical viewpoint, it is preferable to use (A2) one to three copolymer mixtures obtained from one to three monomer mixtures having different average weight ratios. Copolymer mixture (A-2)
When one copolymer mixture is used, that is, when a total of two copolymer mixtures are used, they are conveniently referred to as copolymer mixtures (A _i ) and (A _ii ), and these (A2)
Assuming that the average weight ratios are (X _i ) and (X _ii ), respectively, it is preferable that 5 ≦ (X _i ) <8 (% by weight) and 8 ≦ (X _ii ) ≦ 16. Further, when two copolymer mixtures are used as the copolymer mixture (A-2), that is, when a total of three copolymer mixtures are used, they are conveniently used as the copolymer mixture (A _i ), (A _ii ) and (A _iii ), and _assuming that these (A2) average weight ratios are (X _i ), (X _ii ) and (X _iii ), respectively, 5 ≦ (X _i ) <8 (% by weight) It is preferable that 8 ≦ (X _ii ) ≦ 16 (% by weight) 16 <(X _iii ) ≦ 30 (% by weight).

(A2) Due to the presence of a large number of copolymer mixtures having different average weight ratios, good dispersibility and dispersion retention are exhibited over a wide range of W / C and concrete temperature. In particular, the dispersion retention for a long time becomes stable. As a result, the cement dispersant can sufficiently cope with fluctuations in W / C and temperature.

As described above, the cement dispersant of the present invention comprises
The above monomers (A1) and (A2) are preferably combined with (A1) / (A2) = 0.
The copolymer mixture (A-1) obtained by reacting at a molar ratio in the range of 02 to 4, preferably further contains the copolymer mixture (A-2). (A1) / (A2) is changed at least once during the reaction. The change in the molar ratio may be any of increase, decrease, and a combination thereof. When the molar ratio is changed stepwise or intermittently, the number of changes is preferably 1 to 10, particularly preferably 1 to 5 times. When the molar ratio is continuously changed, a linear change, an exponential change, or any other change may be used, but the degree of change is 0.0001 to 0.2 per minute,
Further, it is preferably 0.0005 to 0.1, particularly preferably 0.001 to 0.05. Further, the molar ratio is preferably such that at least one of the molar ratios (A1) / (A2) before and after the change is in the range of 0.02 to 4, and particularly the molar ratios (A1) / (A2) before and after the change are both It is preferably in the range of 0.02 to 4. Further, as described above, the variation of the molar ratio has various aspects, and in any case, the difference between the maximum value and the minimum value of the molar ratio (A1) / (A2) in the total copolymerization reaction is,
Preferably it is at least 0.05, especially in the range of 0.05 to 2.5.

The copolymer mixture (A) of the present invention comprises (A1) / (A
2) It can be obtained by a production method having a step of performing polymerization by changing the molar ratio at least once.
Simultaneously with the start of the dropping of the aqueous solution of 1), the dropping of the monomer (A2) is started, and the dropping is performed for a predetermined time while changing the dropping flow rate (parts per minute) so that each molar ratio is within a predetermined range. Method. In this method, the amount of change in the monomer (A1) / (A2) molar ratio (difference between the maximum value and the minimum value) is preferably 0.05 to 2.5, and more preferably 0.1 to 2. The copolymer mixture (A) obtained by changing the molar ratio even once during the reaction as in this method is a copolymer obtained by reacting at a constant (A1) / (A2) molar ratio. It is presumed that this is a mixture of a large number of copolymers having a wider distribution of the (A1) / (A2) molar ratio.

Incidentally, 30% or more of the total weight of the monomers, especially
It is preferable to produce 50 to 100% by changing the drop flow rate as described above.

The polymerization reaction may be performed in the presence of a solvent.
Examples of the solvent include water, lower alcohols such as methanol, ethanol, isopropanol and butanol; benzene,
Aromatic hydrocarbons such as toluene and xylene; alicyclic hydrocarbons such as cyclohexane; aliphatic hydrocarbons such as n-hexane; esters such as ethyl acetate; ketones such as acetone and methyl ethyl ketone. Among these, water and lower alcohols are preferable from the viewpoint of easy handling and solubility of the monomer and the polymer.

In the copolymerization reaction, a polymerization initiator can be added. As the polymerization initiator, organic peroxides, inorganic peroxides, nitrile compounds, azo compounds,
Examples thereof include a diazo compound and a sulfinic acid compound. The amount of the polymerization initiator to be added may be monomer (A1), monomer
It is preferably 0.05 to 50 mol% based on the total of (A2) and other monomers.

In the copolymerization reaction, a chain transfer agent can be added. Examples of the chain transfer agent include lower alkyl mercaptan, lower mercapto fatty acid, thioglycerin, thiomalic acid, 2-mercaptoethanol, and the like. The reaction temperature of the copolymerization reaction is preferably from 0 to 120 ° C.

The obtained copolymer mixture can be subjected to a deodorizing treatment, if necessary. In particular, when a thiol such as mercaptoethanol is used as the chain transfer agent, an unpleasant odor tends to remain in the polymer, and thus it is desirable to perform a deodorizing treatment.

An acid type copolymer mixture obtained by the above-mentioned production method can be used as a dispersant for cement even if it is in an acid type, but from the viewpoint of suppressing ester hydrolysis due to acidity. Therefore, it is preferable to form a salt by neutralization with an alkali. Examples of the alkali include a hydroxide of an alkali metal or an alkaline earth metal, ammonia, mono, di, and trialkyl (having 2 to 2 carbon atoms).
8) Amine, mono, di, trialkanol (C2-C2)
8) Amines and the like. When using a (meth) acrylic acid-based polymer as a dispersant for cement,
Partial or complete neutralization is preferred. The copolymer mixture salt in the present invention refers to a salt obtained by partially or completely neutralizing the acid-type copolymer mixture. The acid-type copolymer mixture also includes a copolymer mixture obtained by partially using a salt as the monomer (A2).

The weight average molecular weight of the copolymer mixture obtained by the above production method [gel permeation chromatography, in terms of polyethylene glycol, column: G4000PWXL + G2500PWXL (manufactured by Tosoh Corporation), eluent: 0.2 M Phosphate buffer / acetonitrile = 7/3 (volume ratio)] is preferably 10,000 to 200,000, and 20,000 to 100,000 in order to obtain sufficient dispersibility as a dispersant for cement.
Is particularly preferred.

Further, acrylonitrile, (meth)
A copolymerizable monomer such as acrylamide, styrene, alkyl (meth) acrylate (having 1 to 12 carbon atoms which may have a hydroxyl group), and styrenesulfonic acid may be used in combination. These can be used in a proportion of not more than 50% by weight, more preferably not more than 30% by weight of the total monomers, but 0% by weight is preferred.

[Component (B)] Among the components (B), oxycarboxylic acid is gluconic acid, glucoheptonic acid, arabonic acid,
One or more selected from malic acid and citric acid are preferred. Examples of the salt of oxycarboxylic acid include organic salts and inorganic salts such as sodium salt, potassium salt, calcium salt, magnesium salt, ammonium salt and triethanolamine salt. In the component (B), the saccharide is preferably one or more compounds selected from monosaccharides, oligosaccharides, and polysaccharides. Monosaccharides include glucose, fructose, galactose, saccharose, xylose, abitose, repose, isomerized sugars and the like, and oligosaccharides include disaccharides, trisaccharides, dextrins and the like. In addition, molasses containing these monosaccharides and oligosaccharides can be mentioned. (B)
Among the components, the sugar alcohol is preferably sorbitol.

The component (B) is preferably an oxycarboxylic acid or a salt thereof, or a saccharide, and particularly preferably a saccharide. Under severe conditions where the concrete temperature exceeds 30 ° C., saccharose, monosaccharides such as glucose, and oxycarboxylic acids such as gluconic acid and salts thereof are preferred.

[Cement Dispersant] In the cement dispersant of the present invention, if the dispersibility, material separation resistance, strength development, versatility, etc. of the cement composition are well exhibited, the above copolymer mixture (A ) [Hereinafter also referred to as component (A)] and component (B) can be used together in any ratio. However, the amount of the component (B) is
It is desirable to determine taking into account the strength development due to setting delay of the cement composition, the specific weight ratio of both, (A)
Component / (B) component = 100/1 to 100/50 is preferable, and 100/3
-100/40 is more preferred, and 100 / 3-100 / 30 is even more preferred.

The components (A) and (B) may be added to the concrete after mixing them in advance, or may be added separately. The components are first diluted with kneading water and then added. Is also good.

The cement dispersant of the present invention includes a copolymer obtained by copolymerizing the monomer (A1) and the monomer (A2) represented by the component (A) without changing the molar ratio. The polymer (C-1) can be used in combination. Examples of the monomer used for producing the copolymer (C-1) include those exemplified above for the monomer (A1) and the monomer (B2). Since the copolymer (C-1) has different performances depending on n in the general formula (a1), an appropriate n for the required characteristics is taken into account in consideration of the types and the amounts of the components (A) and (B). Select. Specifically, (1) a copolymer (C-1-i) using a monomer in which n in the general formula (a1) is 1 or more and less than 50 (2) n in the general formula (a1) Copolymer (C-1-ii) using a monomer of 50 or more and less than 110 (3) Copolymer (C-ii) using a monomer of n of 110 or more and 300 or less in general formula (a1) 1-iii), and the components (A) and (B) may be used in combination in consideration of the performance and use of each component.

The cement dispersant of the present invention contains at least one kind of monomer (C ′) represented by the following general formula (c1):
And a copolymer (C-2) obtained by copolymerizing maleic acid or its salt or anhydride (C ″).
The weight average molecular weight of the copolymer (C-2) is preferably from 300 to 300,000, more preferably from 5000 to 100,000. This molecular weight is
It is measured similarly to the component (A). The copolymer (C-2) is Marialim EKM, Marialim AKM (both Nippon Oil & Fats), Super
A commercially available product under the trade name of 200 (Denki Kagaku) can also be used. R ^c1 O (R ^c2 O) _r R ^c3 (c1) (wherein, R ^c1 is an alkenyl group having 2 to 5 carbon atoms, preferably a vinyl group, an allyl group, a methallyl group, and more preferably an allyl group. R ^c2 : carbon Alkylene group R ^{c3 of the} number 2-3, preferably 2, a hydrogen atom or an alkyl group having 1-3 carbon atoms, preferably a methyl group r: 2-150, preferably 2-90, more preferably 10-6.
0, more preferably a number from 20 to 50. ).

These copolymers (C-1) and (C-2) (hereinafter referred to as (C)
) May be appropriately determined in consideration of the amounts of the component (A) and the component (B), but when the feature of the component (A) is mainly used, [(C) / [( A) + (C)]] × 100 is more than 0 and less than 50 (% by weight)
It is more preferably more than 0 and less than 30 (% by weight), more preferably more than 0 and less than 20 (% by weight). In consideration of the mutual effect of the copolymer mixture (A) and the copolymer (C), [(A) / [(A) + (C)]] × 100 is more than 0 and less than 50 (% by weight). Can be used, and in this case, more preferably more than 0
It is less than 30 (% by weight), more preferably more than 0 and less than 20 (% by weight).

The cement dispersant of the present invention may be used in combination with melamine sulfonic acid formalin condensate (C-3). Water-soluble salt of melamine sulfonic acid formalin condensate was obtained by reacting melamine with formaldehyde
A part of methylol group is sulfomethylated by reacting bisulfite with N-methylolated melamine, and then an acid is added to dehydrate and condense the methylol group to form a formalin condensate,
It is a known dispersant obtained by neutralization with an alkali (for example, see Japanese Patent Publication No. 63-37058). As the alkali,
Examples thereof include hydroxides of alkali metals or alkaline earth metals, ammonia, mono, di, and trialkyl (2 to 8 carbon atoms) amines, and mono, di, and trialkanol (2 to 8 carbon atoms) amines. As a commercial product, Mighty 15
0V-2 (Kao Corporation), SMF-PG (Nissan Chemical Industries, Ltd.), Melflow (Mitsui Chemicals, Ltd.), Melment
F-10 (Showa Denko KK) and the like. The molecular weight of (C-3) is preferably 1,000 to 100,000, more preferably 5,000 to 50,000, particularly preferably 5,000 to 20,000 (gel permeation chromatography,
Polystyrene sulfonic acid conversion). The weight ratio of (C-3) to the copolymer mixture (A) is (A) / (C-3) = 100/1 to
100/100 is preferred, 100/5 to 100/50 is more preferred, and 100/5 to 100/30 is more preferred.

Further, a water-soluble polymer (C-4) other than the above, which is rich in viscosity, may be used in combination. As the water-soluble polymer, at least one selected from the following (C-4-1) to (C-4-8) is preferable. (C-4-1) nonionic cellulose ether, (C-4-2) acrylic acid copolymer, (C-4-3) polyalkylene glycol, (C-
4-4) Polysaccharide obtained by fermentation, (C-4-5) xanthan gum, (C-4-6) monohydric alcohol having 6 to 30 carbon atoms or monovalent mercaptan having 6 to 30 carbon atoms or 6 carbon atoms Alkylene oxide derivatives having an average of 10 to 1000 mol of alkylene oxide added to an alkylphenol having an alkyl of 30 to 30 or an amine having 6 to 30 carbon atoms or a carboxylic acid having 6 to 30 carbon atoms, (C-4-7) having 6 carbon atoms An alkylene oxide derivative obtained by adding an average of 10 to 1000 mol of an alkylene oxide to a monohydric alcohol or a monohydric alcohol having 6 to 30 carbon atoms or a monohydric mercaptan having 6 to 30 carbon atoms, and one or more epoxy groups. The reaction product with the compound having, (C-4-8) a polysaccharide or an alkylated or hydroxyalkylated derivative thereof, a part or all of the hydrogen atoms of the hydroxyl group partially forms a hydrocarbon chain having 8 to 40 carbon atoms. As a hydrophobic substituent having (P), a sulfonic acid group, a carboxyl group, a phosphate group and a sulfate group and an ionic hydrophilic group having as a partial structure at least one group selected from the group consisting of salts thereof ( A polysaccharide derivative substituted with Q).

The weight ratio of the water-soluble polymer (C-4) to the component (A) is
When using the above (C-4-1), (C-4-2), (C-4-4), (C-4-6), (C-4-7), the weight ratio of both, (A) / (C-4) = 100 / 0.02
-100/1000 is preferable, and 100 / 0.2-100 / 1000 is more preferable. When the above (C-4-3) is used, the weight ratio between the two is preferably (A) / (C-4) = 100/2 to 100/5000,
0/2 to 100/3000 are more preferred. In addition, the above (C-4-
5) When (C-4-8) is used, the weight ratio between them is (A) / (C-
4) = 100 / 0.02 to 100/100 is preferable, and 100 / 0.2 to 100 /
20 is more preferred, and 100 / 0.2 to 100/10 is particularly preferred.

The cement dispersant of the present invention can also contain other additives (materials). For example, resin soap,
Saturated or unsaturated fatty acid, sodium hydroxystearate, lauryl sulfate, alkylbenzenesulfonic acid (salt), alkane sulfonate, polyoxyalkylenealkyl (phenyl) ether, polyoxyalkylenealkyl (phenyl) ether sulfate (salt), polyoxyalkylene AE agent such as alkyl (phenyl) ether phosphate (salt), protein material, alkenyl succinic acid, α-olefin sulfonate; inorganic retarder such as magnesium silicofluoride, phosphoric acid or its salt, borate; amino Organic retarders such as carboxylic acids or salts thereof, alkali-soluble proteins, humic acids, tannic acids, phenols, polyhydric alcohols, phosphonic acids and derivatives thereof; foaming agents; thickening agents; silica sand; AE water reducing agents; Calcium, nitrite Calcium, calcium nitrate, calcium bromide, soluble calcium salts such as calcium iodide, iron chloride, chlorides such as magnesium chloride, sulfate,
Potassium hydroxide, sodium hydroxide, carbonate, thiosulfate, formic acid (salt), alkanolamine, etc., as early-strength agents or accelerators; blowing agents; resin acids (salts), fatty acid esters, oils and fats,
Waterproofing agents such as silicone, paraffin, asphalt, and wax; blast furnace slag; fluidizing agents; antifoaming agents; antifoaming agents; fly ash; Agents; polymer emulsions such as alkyl (meth) acrylates.

The cement dispersant of the present invention can be used for self-leveling, refractories, plasters, gypsum slurries, lightweight or heavy concrete, AE, repair, prepacked, in addition to ready-mixed concrete and concrete vibration products. It is useful in any field of various concretes, such as for trammies, grouts, and for cold weather. The cement dispersant of the present invention is 0.01 to 5.0% by weight based on cement.
It is preferably used (as solids), in particular in a proportion of 0.05 to 2.0% by weight.

[0049]

EXAMPLES <Copolymer mixture (A)> Copolymer mixtures shown in Tables 1 and 2 were produced. At that time, the monomers (A1) and (A2)
The molar ratio (A1) / (A2) was changed during the reaction.

[0050]

[Table 1]

[0051]

[Table 2]

(Note) In Tables 1 and 2, MPEGMM is an abbreviation for methoxypolyethylene glycol monomethacrylate, and the number in parentheses is the average number of moles of ethylene oxide added (the same applies hereinafter). MAA is methacrylic acid (the same applies hereinafter). In Table 2, "-Na" means a sodium salt. The copolymer mixtures in Tables 1 and 2 were produced according to the following production examples.

<Production Example 1: Copolymer mixture AI and AIN
Production of a> Charge 329.9 parts by weight of water into a glass reaction vessel,
After the replacement with nitrogen, the temperature was raised to 78 ° C. in a nitrogen atmosphere. next,
216.4 parts by weight of a 60% aqueous solution of MPEGMM (120), 90% of MPEGMM (9)
% Aqueous solution 75.5 parts by weight, methacrylic acid 38.3 parts by weight and a 5% ammonium persulfate aqueous solution 27.7 parts by weight and 5% -2
-30.8 parts by weight of an aqueous mercaptoethanol solution was added dropwise in 55 minutes, and 78.7 parts by weight of a 60% aqueous solution of MPEGMM (120), MPEGMM (9)
Of a 90% aqueous solution of 32.1 parts by weight, methacrylic acid 9.7 parts by weight and a 5% ammonium persulfate aqueous solution 8.2 parts by weight and 5%
9.2 parts by weight of an aqueous solution of 2-mercaptoethanol was added dropwise over 20 minutes, and 59.0 parts by weight of a 60% aqueous solution of MPEGMM (120) was added.
A mixture of 26.0 parts by weight of a 90% aqueous solution of PEGMM (9), 5.6 parts by weight of methacrylic acid, 5.4 parts by weight of a 5% aqueous solution of ammonium persulfate and 6.0 parts by weight of a 5% -2-mercaptoethanol aqueous solution were added dropwise in 15 minutes. Molar ratio per dropping time (A1) / (A2)
Are shown in Table 2. After completion of the dropwise addition, the mixture was aged at 78 ° C. for 60 minutes, and then 20.7 parts by weight of a 5% ammonium persulfate aqueous solution was added in 5 minutes. After aging at 78 ° C. for 120 minutes, the polymerization reaction was completed, and a copolymer mixture AI shown in Table 1 was obtained.

Furthermore, a 48% aqueous sodium hydroxide solution 20.8
The mixture was neutralized by adding parts by weight, and the copolymer mixture AI shown in Table 2 was added.
-Na was obtained. The pH (20 ° C.) of a 5% by weight aqueous solution of the copolymer mixture AI-Na was 5.9.

In Tables 1 and 2, (A1) / (A2)
Copolymers A-II and A-II-N in which the molar ratio of
a was produced according to Production Example 1.

<Production Example 2: Production of copolymer mixture A-IV-Na> 423 parts by weight of water was placed in a glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube, and a reflux condenser. The charged nitrogen was replaced. Subsequently, after the temperature was raised to 70 ° C. under a nitrogen atmosphere, 44.9 parts by weight of MPEGMM (9), methacrylic acid 18.
2% by weight of a dropping monomer liquid (1) and 5% -2-
A solution of 14.2 parts by weight of an aqueous solution of mercaptoethanolic acid and 13.8 parts by weight of an aqueous solution of 5% ammonium persulfate were simultaneously added dropwise over 15 minutes, and then a mixture of 250.5 parts by weight of MPEGMM (9) and 65.2 parts by weight of methacrylic acid was added. Body fluid (2) and 5%-
Three solutions, 59.2 parts by weight of a 2-mercaptoethanolic acid aqueous solution and 57.6 parts by weight of a 5% ammonium persulfate aqueous solution, were added dropwise over 75 minutes, and the addition was completed in 90 minutes in total. After completion of the dropwise addition, the mixture was aged at the same temperature for 1 hour, and 21.4 parts by weight of a 5% ammonium persulfate aqueous solution was added dropwise over 10 minutes, and then aged at 70 ° C. for 2 hours to complete the polymerization reaction. 48% aqueous sodium hydroxide solution
The mixture was neutralized by adding 57 parts by weight, and the copolymer mixture A-
IV-Na was obtained. The pH of a 5% by weight aqueous solution of the copolymer mixture A-IV-Na was 6.0 (20 ° C.).

In Tables 1 and 2, (A1) / (A2)
Copolymers A-III, A-III in which the molar ratio of
-Na was produced according to Production Example 2.

<Component (B)> The component (B) shown in Table 3 was used.

[0059]

[Table 3]

<Copolymer (C)> Copolymers shown in Table 4 were produced. At that time, the weight ratio of the monomers (C1) and (C2) was kept constant.

[0061]

[Table 4]

(Note) In Table 4, AE is an abbreviation for methoxypolyethylene glycol (n = 40) monoallyl ether;
MA is maleic anhydride and MAA is methacrylic acid.

<Concrete test conditions> (1) Material W = tap water C = ordinary Portland cement (specific gravity = 3.16) LC = limestone fine powder (specific gravity = 2.70, Blaine value = 5200) Fine aggregate = Kanto Kimitsu (specific gravity) = 2.63) Coarse aggregate = broken bone from Ibaraki (specific gravity = 2.62) W / C = (unit weight of W / unit weight of C) x 100% s / a = [fine aggregate volume / (fine aggregate volume + Coarse aggregate volume)]
× 100% (2) Composition Table 5 shows the composition of the concrete prepared from the above materials.

[0064]

[Table 5]

(3) Performance Evaluation The material and dispersant for 30 liters of concrete were put into a forced biaxial mixer (50 liters), kneaded for 90 seconds, and the following performances immediately after discharge were evaluated. Formulation I is at room temperature 26 ° C
(Concrete temperature 28 ° C.) and Formulation II was carried out at room temperature 31 ° C. (concrete temperature 33 ° C.). The evaluation method was changed as follows for Formulations I and II. The results are shown in Tables 6 and 7, where Table 6 shows the results for concrete mix I in Table 5 and Table 7 shows the results for concrete mix II in Table 5.

(3-1) <Evaluation by Formulation I> (3-1-1) Addition rate Addition of the dispersant solid to the total powder required for the initial slump value (JIS-A1101) to be 23 ± 1 cm. Measure the rate.
The smaller the value, the better the dispersibility.

(3-1-2) Retention The percentage of the slump value after 60 minutes with respect to the initial slump value. The larger the value, the better the dispersion retention.

(3-1-3) Falling time: The concrete after measuring the slump value is 5 mm wide from the concrete.
The mortar obtained by separating the coarse aggregate with a sieve is filled into an apparatus having the shape shown in FIG. 1 prepared by processing stainless steel (SUS304) with the lower discharge opening closed, and the upper inlet opening After rubbing, the lower discharge opening is opened to allow the mortar to flow naturally, and the time (flowing time) until holes are confirmed in at least a part of the mortar when visually observed from the upper charging opening is measured, This was used for viscosity evaluation. The shorter the flow time, the lower the viscosity of the concrete and the lower the resistance to material separation.

(3-1-4) Curing time The final time of the mortar whose flow time was measured was measured by the ASTM-C403 method.

(3-2) <Evaluation by Formulation II> (3-2-1) Addition rate The solid dispersant required to reach a slump flow value of 650 ± 10 mm [Guidelines for Highly Fluid Concrete Construction (Concrete Library 93)] The addition rate of the total powder to the total powder is measured. The smaller the value, the better the dispersibility.

(3-2-2) Retention The percentage of the slump value after 60 minutes with respect to the initial slump flow value. The larger the value, the better the dispersion retention.

(3-2-3) Falling time A mortar obtained by separating coarse aggregate from concrete having a slump flow value of 650 ± 10 mm with a sieve having a mesh size of 5 mm was prepared by processing stainless steel (SUS304). After filling the apparatus having the shape shown in FIG. 1 with the lower discharge opening closed and rubbing off the surface of the upper charging opening, the lower discharging opening was opened to allow the mortar to flow naturally and visually observed from the upper charging opening. Occasionally, the time until pores were confirmed in at least a part of the mortar (flow time) was measured and used for evaluation of viscosity. The shorter the flow time, the lower the viscosity of the concrete and the lower the resistance to material separation.

[0073]

[Table 6]

In the table, X is the average weight ratio of the monomer (A2) to all monomers in the production of the copolymer mixture (A), and Y is the production weight of the copolymer (C). Is the average weight ratio of the monomer (C2) to all the monomers (hereinafter the same).

From Comparative Example 1-1, it can be seen that the component (A) alone does not have sufficient retention at a concrete temperature of 28 ° C. Further, from Comparative Example 1-2, when the component (B) is used in combination with the copolymer (C) having a small number of EO addition moles, the retention is improved as compared with Comparative Example 1-1, but the curing time is reduced. Understand. Further, from Comparative Example 1-3, a large copolymer EO addition molar number (C)
In addition, when the component (B) is used in combination, the retention is improved as compared with Comparative Example 1-1, but it can be seen that the viscosity of concrete is greatly increased, and the pumping property may be reduced in fresh concrete applications. On the other hand, from Examples 1-1 to 1-15, (B)
It can be seen that the combined use of the components improves the retention and minimizes the setting time delay without increasing the viscosity of the concrete. In particular, Examples 1-9, 1-10, 1
From -14 and 1-15, it can be seen that when components having different average weight ratios X are used in combination as component (A), the retention can be improved while maintaining other performances stably.

[0076]

[Table 7]

From Comparative Example 2-1, the concrete temperature was 3 in the combination system of the component (A) and the copolymer (C) having a large number of moles of EO addition.
It can be seen that when the temperature reaches 3 ° C., the retention is significantly reduced. On the other hand, from Examples 2-1 to 2-6, it can be seen that the use of the component (B) in the system of Comparative Example 2-1 can improve the retention. In particular, from Examples 2-2 to 2-9, even if a known dispersing agent or a water-soluble polymer is further used in combination with the system of Example 2-1, it is possible to obtain an excellent retention improvement effect. Understand. In addition, it can be seen from Example 2-10 that good results are obtained even when the sodium salt of the copolymer mixture is used.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an apparatus used for measuring a flow time in an example.

[Explanation of symbols]

 1 Upper opening 2 Lower opening

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C04B 24/06 C04B 24/06 24/10 24/10 24/38 24/38 Z C08F 8/44 C08F 8/44 220 / 28 220/28 290/06 290/06 // C04B 103: 40 C04B 103: 40 (72) Inventor Yamato Fuji Sakura 1334 Minato, Wakayama-shi, Wakayama Prefecture Kao Research Institute F-term (reference) 4J027 AC02 AC03 AC04 AC06 BA04 BA06 CA10 CA24 CA29 CB02 CB03 CB09 CC02 4J100 AE18P AJ01Q AJ02Q AJ08Q AJ09Q AK03Q AK08Q AK13Q AK19Q AK20Q AK21Q AK24Q AK25Q AK26Q AK31Q AK32H03 HC03 HC03 HC04 HC03 BA08

Claims (5)

[Claims] [Claim 1] At least one kind of monomer (A1) represented by the following general formula (a1) and at least one kind (A2) of a monomer represented by the following general formula (a2) A copolymer mixture or a copolymer mixture obtained by copolymerization, wherein the molar ratio (A1) / (A2) of the monomers (A1) and (A2) is changed at least once during the reaction A salt of a copolymer mixture neutralized with an alkali (hereinafter, both are referred to as a copolymer mixture (A)), and oxycarboxylic acid or a salt thereof, one or more compounds selected from the group consisting of sugars and sugar alcohols (B ) And a cement dispersant. Embedded image (Wherein, R ¹ , R ² : a hydrogen atom or a methyl group m: a number of 0 to 2 R ³ : a hydrogen atom or —COO (AO) _n X p: a number of 0 or 1 AO: a carbon number of 2 to 4) Oxyalkylene group or oxystyrene group n: a number of 2 to 300 X: represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms.) (Wherein, R ^{4 to} R ^{6 are a} hydrogen atom, a methyl group or (CH ₂ ) m ₁ COOM ² ;
(CH ₂ ) m ₁ COOM ² may form an anhydride with COOM ¹ or another (CH ₂ ) m ₁ COOM ² , in which case the groups M ¹ and M ² are absent. M ¹ , M ² : hydrogen atom, alkali metal, alkaline earth metal,
Ammonium group, alkyl ammonium group or substituted alkyl ammonium group m1: represents the number of 0 to 2. ) 2. An average weight ratio (X _I ) of the monomer (A2) to all the monomers for producing the copolymer mixture (A) is from 1 to 30.
The cement dispersant according to claim 1, which is in the range of (% by weight). 3. The cement dispersant according to claim 1, wherein the oxycarboxylic acid is at least one selected from gluconic acid, glucoheptonic acid, arabonic acid, malic acid and citric acid. 4. The cement dispersant according to claim 1, wherein the saccharide is at least one compound selected from monosaccharides, oligosaccharides and polysaccharides. 5. The cement dispersant according to claim 1, wherein the sugar alcohol is sorbitol.