JP2001348259A - Cement dispersant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cement dispersant capable of improving the dispersion characteristics of stiff concrete while maintaining viscosity and properties with respect to the exhibition of strength of the concrete, or improving dispersion retentivity of the stiff concrete while maintaining excellent dispersion characteristics and viscosity of the concrete, under various production conditions of the stiff concrete. SOLUTION: This cement dispersant contains: a copolymer mixture A obtained by copolymerizing a specific monomer A1 such as ethylenically unsaturated carboxylic acid derivative having a polyoxyalkylene group, and another specific monomer A2 such as (meth)acrylic acid, wherein the monomer molar ratio of A1/A2 is at least once changed in the process of the copolymerization reaction; and a copolymer B obtained by copolymerizing a specific monomer B1 such as ethylenically unsaturated carboxylic acid derivative having a polyoxyalkylene group, and another specific monomer B2 such as (meth)acrylic acid.

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 produced from a polyalkylene glycol mono (meth) acrylate monomer and a (meth) acrylate monomer is known.

In this type of copolymer, characteristic performance can be imparted by changing the number of moles of alkylene oxide (hereinafter referred to as AO) (hereinafter, represented by n) and the monomer ratio. It is disclosed that there is. For example, in JP-A-58-74552, n may use a monomer of 1 to 100, and in JP-A-8-12396, n may use a monomer of 50 to 100. In JP-A-7-223852, n is
It is described that when a monomer having a size larger than 110 is used, the dispersibility is excellent. As a polycarboxylic acid-based cement dispersant obtained by copolymerizing two or more monomers having different n, JP-A-7-247150 discloses that monomers having n of 110 to 300 and 1 to 30 are copolymerized. Dispersants are disclosed. However, when these are used alone, they have a very low versatility with respect to actual concrete manufacturing conditions in which the mixing conditions vary widely and the temperature varies over a wide range throughout the year.

Therefore, in order to expand versatility, two different
It has been proposed to blend more than one copolymer to make up for the mutual disadvantages. For example, in Japanese Patent Application Laid-Open No. 9-40446,
A mixture of copolymers obtained by copolymerizing monomers in which n is 100 to 300 and 1 to 30 is disclosed. However, for example, when the monomer weight ratio of the copolymer used together is close to each other,
If a material having a small versatility and a monomer weight ratio far apart is selected, a region where mutual defects cannot be compensated is generated, and a region where performance is insufficient is generated. In order to solve such a problem, it is necessary to use a large number of copolymers having different monomer weight ratios. However, this method has low production efficiency and increases production cost for mass production. .

Further, the present inventors have proposed, as a cement dispersant having higher dispersibility and flowability, a copolymer mixture obtained by copolymerizing two specific monomers, It has been proposed to use a copolymer mixture whose molar ratio is changed at least once in the course of the reaction (Japanese Patent Application No. Hei 10-214,878).
11-361108). This dispersant is more efficient and cheaper for mass production than when different copolymers are blended.

[0006]

When so-called hardened concrete is used for a vibrating product, a method of filling the hardened concrete into a form is often used. Compacted concrete has a slump value of less than 15 cm and generally has a small amount of cement and water. Therefore, a large amount of aggregate must be mixed with a relatively small amount of cement paste. Fluidity after kneading (slump value)
Contradictory properties of suppressing viscosity while keeping the viscosity as low as possible are required. It is conceivable to cope with such a demand from the viewpoint of adding a cement dispersant. However, in the case of hardened concrete, there is a limitation that only a small amount of a dispersant can be added in order to suppress the fluidity with a small amount of cement paste. Under such restrictions, in order to knead a relatively large amount of aggregate in a short time and keep the viscosity low, the dispersant exhibits strong dispersibility in the presence of a small amount of water. Is required. In addition, when using compacted concrete for centrifugal molding products, concrete with a low slump value is manufactured and used with a cement paste consisting of a relatively large amount of cement and a small amount of water. The agent is required to exhibit strong dispersibility in the presence of a small amount of water.

[0007] However, no conventional cement dispersant has been found that can sufficiently satisfy such required properties for the stiffened concrete. Therefore, the present invention relates to various concrete production conditions of the stiffened concrete. It is another object of the present invention to provide a cement dispersant which can improve dispersibility while maintaining viscosity and strength development, or improve dispersion retention while maintaining excellent dispersibility and viscosity.

[0008]

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)
(A1) / (A2) is a copolymer mixture (A) is changed at least once during the reaction, and at least one of the monomers represented by the following general formula (b1) (B1), The following general formula (b2-
1) and a copolymer (B) obtained by copolymerizing at least one selected from the monomers represented by the following general formula (b2-2) and a monomer represented by the following general formula (b2-2): The present invention relates to a contained cement dispersant.

[0009]

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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) Oxyalkylene group or oxystyrene group of 4 to 4, preferably oxyalkylene group of 2 to 3 carbon atoms n: 2 to 300 X: hydrogen atom or alkyl group of 1 to 18 carbon atoms, preferably hydrogen atom or carbon number Represents an alkyl group of 1 to 3)

[0011]

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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. )

[0013]

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Wherein R ⁷ , R ⁸ : hydrogen atom or methyl group R ⁹ : alkylene group having 2 to 3 carbon atoms R ¹⁰ : hydrogen atom or alkyl group having 1 to 3 carbon atoms q: the number of 0 to 2 r: represents a number of 50 or more and less than 110.)

[0015]

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Wherein R ^{11 to} R ^{13 are a} hydrogen atom, a methyl group or (CH ₂ ) _s COOM ⁴ , and (CH ₂ ) _s COOM ⁴ is substituted with COOM ³ or another (CH ₂ ) _s COOM ⁴ May form anhydrides, in which case the M ³ , M ⁴
Does not exist. R ¹⁴ : hydrogen atom or methyl group M ³ , M ⁴ , Y: hydrogen atom, alkali metal, alkaline earth metal, ammonium group, alkylammonium group or substituted alkylammonium group s: represents the number of 0 to 2. )

[0017]

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 importance 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. Further, when 300 <n, the dispersibility is reduced, and the polymerizability at the time of production is also reduced.
Is not more than n, more preferably n ≦ 200, further preferably n ≦ 150, and particularly preferably n ≦ 130.

When importance is placed on reducing the viscosity of concrete, 2 ≦ n ≦ 100 is preferable, and more preferably 5 ≦ n ≦ 100.
≦ n ≦ 80, 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

[0022]

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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.)

[0024]

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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: 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), preferably containing a copolymer mixture (A) obtained by reacting at a molar ratio in the range of (A1) / (A2) = 0.02-4, these molar ratio (A1) / (A2) is changed at least once during the reaction. And, in the present invention, the copolymer mixture (A) was obtained with an average weight ratio (X _II ) different from the average weight ratio of the monomer (A 2) to all the monomers for producing the monomer mixture (X _I ). It is preferable to use the copolymer mixture (A ′) in combination. That is, the copolymer mixture (A ') is the monomer (A
1) and (A2) are preferably reacted at a molar ratio of (A1) / (A2) = 0.02 to 4 to obtain a copolymer mixture, wherein the molar ratio (A1) / (A2) has been changed at least once during the reaction, and the average weight ratio of the monomer (A2) to all the monomers for producing the copolymer mixture (A ′)
(X _II ) is different from the average weight ratio (X _I ) of the copolymer mixture (A). The average weight ratio is [total amount of monomer (A2) /
Total monomer amount] × 100 (% by weight)
It is preferably in the range of 0 (% 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
Preferably, the difference is 0.1 (wt%), more preferably at least 0.5 wt%, especially at least 1.0. Incidentally, the copolymer mixture (A) and (A '), the monomers used in the production (A1), even if the type of (A2) is different, in the present invention, the average weight ratio (X _I ),
(X _II) but need only be different, the monomer (A1), to use the same type of the (A2) preferably.

In the present invention, the average weight ratio (X _I ) of the copolymer mixture (A) is 1 to 30% by weight, more preferably 7 to 20% by weight, especially 8%.
Preferably it is 1616% by weight. Then, by assembling a compounding system using the copolymer mixture (A) as a main component, a concrete water reducing agent having a well-balanced performance can be obtained.

That is, in the present invention, the dispersibility of the copolymer mixture (A) is even lower than that of W / C in which good dispersibility is exhibited.
If W / C, it is larger than the copolymer mixture (A2)
By using a copolymer mixture having an average weight ratio in combination, a cement dispersant exhibiting good dispersibility even under these conditions can be obtained. Similarly, when the temperature is even lower than the temperature at which the dispersibility of the copolymer mixture (A) is well expressed, the copolymer mixture having a larger average weight ratio than the copolymer mixture (A2) is used in combination. By doing so, a cement dispersant exhibiting good dispersibility even under these conditions can be obtained. In this case, when the (A2) average weight ratio differs by 0.5% by weight or more, particularly 1.0% by weight or more, the effect of the improvement becomes clearer.

In order to improve the dispersion retention under the production conditions of higher concrete temperature, the copolymer mixture (A)
It is effective to use a copolymer mixture having a smaller (A2) average weight ratio than the above.

The combination ratio of the copolymer mixture (A) and (A ') is not limited. However, when the concrete mixture is constant, (A2) the dispersion having a large average weight ratio is increased by increasing the ratio of the larger one by weight. On the other hand, (A2) the dispersion retention at high temperatures can be stabilized by reducing the ratio of the larger one having the larger average weight ratio.

In the present invention, as the copolymer mixture (A '), a plurality of copolymers each obtained from (A2) 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. 1 as the copolymer (A ')
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 their (A2) average weight When the 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 ′), 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 )
(A2) Assuming that the average weight ratios are (X _i ), (X _ii ), and (X _iii ), respectively, 5 ≦ (X _i ) <8 (% by weight) 8 ≦ (X _ii ) ≦ 16 (% by weight) 16 It is preferable that <(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.
It contains the copolymer mixture (A) obtained by reacting at a molar ratio in the range of 02 to 4, preferably (A '), and in any case, these molar ratios (A1) / (A2) Has been changed at least once during the reaction. The change in the molar ratio is
Any of increase, decrease, and a combination thereof may be used.
When the molar ratio is changed stepwise or intermittently, the number of changes is preferably 1 to 10, particularly preferably 1 to 5 times. Also,
When the molar ratio is continuously changed, the change may be any of a linear change, an exponential change, and other changes, but the degree of change is from 0.0001 to 0.2 per minute, and further from 0.0005 to 0.0005 per minute.
0.1, especially 0.001 to 0.05 is preferred. Further, the molar ratio is at least one of the molar ratio before and after the change (A1) / (A2).
The molar ratio (A1) / (A2) before and after the change is preferably in the range of 0.02 to 4, particularly preferably 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 at least 0. .
05, particularly preferably in the range of 0.05 to 2.5.

Such a copolymer mixture can be obtained by a production method having a step of polymerizing by changing the (A1) / (A2) molar ratio at least once, and specifically, the monomer (A1) At the same time as the dropping of the aqueous solution, the dropping of the monomer (A2) is started,
A method of dropping for a predetermined time while changing the flow rate (parts per minute) so that the respective molar ratios are within a predetermined range can be given. 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 obtained by changing the molar ratio at least once during the reaction as in this method is (A1) / (A2) from the 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 wide distribution of () / (A2) molar ratio.

It should be noted that 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.

In the above method, the change in the molar ratio or the weight ratio may be adjusted by changing the addition rate of all the monomers to be added or by changing the addition rate of only a part of the added monomers. Further, the change of the dropping speed may be performed continuously, stepwise, or a combination thereof. Further, the change amount may be not only a unitary change of increase or decrease, but may be alternately increased and decreased. The monomers to be added may be added individually, or may be added sequentially after preparing two or more types of monomer mixed solutions having different monomer composition ratios in advance. In the case of individual dropping, it is preferable to keep the dropping flow rate of the heaviest added monomer constant and change the dropping flow rate so that other monomers have a predetermined monomer composition. Further, a part of the monomer to be added to the monomer dropping tank is charged, and the remaining monomer is continuously or stepwise changed, and the monomer mixed solution is dropped while being added to the monomer dropping tank. It may be dropped from the tank to the reaction tank. Alternatively, a part of the monomer to be added may be charged into the reactor, and the remaining monomer may be continuously or stepwise changed in flow rate and dropped into the reactor for polymerization.

In the above method, the degree of change in the molar ratio or the weight ratio is adjusted by measuring the flow rate of the monomer to be supplied by using a flow meter or a liquid level meter. In this case, the criteria for determining the specific degree of change depend on the type of monomer and the amount (speed) of the monomer. In general, when the content of the monomer (A1) increases, the flowability becomes better, and when the content of the monomer (A2) increases, the dispersibility becomes better,
Also, when n in the general formula (a1) of the monomer (A1) is small, the curing rate is low and the dispersion retention is low, and when n is large, the curing rate is high and the dispersion retention tends to be high. The molar ratio and the weight ratio at the time of polymerization may be determined according to the performance.

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. It is preferable that the addition of the polymerization initiator be started at the same time as the monomer. The dripping flow rate may be changed or constant,
What is necessary is just to set so that desired molecular weight and reaction rate may be obtained.

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. Particularly when water is used as the solvent, the molecular weight can be adjusted more stably by adding these chain transfer agents. The chain transfer agent can be mixed with the monomer or individually dropped simultaneously with the monomer. The drop flow rate may be changed or constant, and may be adjusted so as to obtain a desired molecular weight. The reaction temperature of the copolymerization reaction is preferably from 0 to 120 ° C.

The obtained polycarboxylic acid polymer can be subjected to a deodorizing treatment as required. 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.

The polycarboxylic acid-based polymer obtained by the above-mentioned production method can be used as a dispersant for cement even in an acid form. It is preferable to form a salt by summation. As this 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. When the (meth) acrylic acid polymer is used as a dispersant for cement, it is preferable to partially or completely neutralize it.

The weight average molecular weight of the polycarboxylic acid polymer obtained by the above production method [gel permeation chromatography, converted to polyethylene glycol, column: G4000PWXL + G2500PWXL (Tosoh Corporation)
Eluent: 0.2 M phosphate buffer / acetonitrile = 7
/ 3 (volume ratio)] is preferably 10,000 to 200,000, and 20,000 to obtain sufficient dispersibility as a dispersant for cement.
~ 100,000 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.

[Copolymer (B)] As the monomer represented by the general formula (b1) used in the production of the copolymer (B), those exemplified for the monomer (A1) can be used. No. The general formula
R ^{7 in} (b1) is preferably a hydrogen atom, and q is preferably 0.

As the monomer represented by the general formula (b2-1), those exemplified for the monomer (A2) can be mentioned.

Examples of the monomer represented by the general formula (b2-2) include allylsulfonic acid, methallylsulfonic acid and salts thereof. The salt is preferably an alkali metal salt, an alkaline earth metal salt, an ammonium salt, or a mono-, di-, or trialkyl (C 2-8) ammonium salt whose hydroxyl group may be substituted.

For example, the copolymer (B) is charged with water in a reaction vessel and heated, and the monomer (B1) and the monomer (B2) are mixed in the presence of a chain transfer agent and the like in a molar ratio. The reaction can be carried out at a constant weight ratio, ripened and then neutralized.

The copolymer (B) functions as a cement dispersant
Is used for all monomers for producing the copolymer.
Average weight ratio of the monomer (B2) (Y_I) Is 1 to 30 (% by weight)
Preferably. The average weight ratio is (the sum of the monomers (B2)
Amount / total monomer amount] × 100 (% by weight). In addition,
Hereinafter, this average weight ratio may be referred to as “(B2) average weight ratio”.
is there. To make the versatility of the copolymer (B) wider,
The polymer (B) has an average weight ratio different from the (B2) average weight ratio (Y_II)
It is preferable to use the copolymer (B ') produced by
No. That is, in the present invention, the copolymer (B)
(B2) from a plurality of monomer mixtures having different average weight ratios.
A plurality of copolymers (B ') each obtained can be used.
You. From a practical point of view, (B2) 1-10 different average weight ratios
Each from a monomer mixture, in particular from 1 to 3 monomer mixtures
1 to 10 copolymers obtained, especially 1 to 3 copolymers
It is preferable to use One copolymer as copolymer (B ')
When coalescence is used, that is, two copolymers are used in total.
When used, they are conveniently referred to as copolymers (B_i), (B_ii)When
And these (B2) average weight ratios are (Y_i), (Y_ii)When
Then, 2 ≦ (Y_i) <5 (% by weight) 5 ≦ (Y_ii) ≦ 15 (% by weight), 5 ≦ (Y_ii) ≦ 10 (weight
%). In addition, two copolymers (B ')
Is used, ie, three copolymers in total
When using isomers, they are conveniently referred to as copolymers (B _i), (B
_ii), (B_iii), And these (B2) average weight ratios are respectively
(Y_i), (Y_ii), (Y_{ii i}), 2 ≦ (Y_i) <5 (% by weight) 5 ≦ (Y_ii) ≦ 10 (wt%) 10 <(Y_iii) ≦ 30 (% by weight).

The copolymers (B) and (B ′) have an average weight ratio (Y _I )
And (Y _II ) are preferably selected to be different by one or more. In the copolymers (B) and (B '), the types of the monomers (B1) and (B2) used in the production may be different or the same, but the same type may be used. It is preferably used.

Further, in order for the copolymer (B) to exhibit strong cement dispersibility without significantly lowering the initial strength of the compacted concrete, r in the general formula (b1) should be 50 or more and less than 110. And r is preferably at least 75, more preferably at least 85. Further, in order for the copolymer (B) to maintain the viscosity of the compacted concrete at a low level, r is preferably less than 100, more preferably less than 95.

[Cement Dispersant] The cement dispersant of the present invention may contain any of the above copolymer mixture (A) (hereinafter referred to as component (A)) and copolymer (B) (hereinafter referred to as component (B)). May be used in combination, and which may be used as the main agent depending on the required characteristics.

In general, the component (A) has relatively high versatility under various production conditions of concrete, but when the component (B) is used in combination, the initial content can be adjusted in accordance with the required characteristics of the hardened concrete. Dispersibility can be improved or stronger viscosity can be developed without significantly affecting strength development and viscosity.

In the present invention, the monomer (B) constituting the component (B)
The r of 1) is 50 or more and less than 110 for the above reason, and in consideration of this, n of the monomer (A1) constituting the component (A) or or (A)
What is necessary is just to determine the combination ratio and the type of the component and the component (B), and an example thereof is as follows.

(1) In the case where the copolymer mixture (A) is used as the main component In the case where the copolymer mixture (A) is used as the main component, in order to make the features of the component (A) widely versatile, the average weight ratio (X _I ) preferably satisfies the above range. In this case, the copolymer
The weight ratio [(B) / [(A) + (B)]] × 100 to the total of the copolymer mixture (A) and the copolymer (B) of (B) is more than 0 and less than 50 (% by weight). It is preferably more than 0 and 30 or less (% by weight), more preferably more than 0 and 20 or less (% by weight).

(2) In the case where the copolymer (B) is used as the main component In the case where the copolymer (B) is used as the main component, in order to make the features of the component (B) widely versatile, (B2) the average weight The ratio (Y) preferably satisfies the above range. In this case, the weight ratio [(A) / [(A) + (B)]] × 100 of the copolymer mixture (A) to the total of the copolymer mixture (A) and the copolymer (B) is 0. It is more than less than 50 (% by weight), preferably more than 0 and 30 or less (% by weight), more preferably more than 0 and 20 or less (% by weight).

The cement dispersant of the present invention has the general formula
(b1) at least one of the monomers in which r is 110 or more and 300 or less (C1), a monomer represented by the general formula (b2-1) and the general formula (b2-2) )) Can be used in combination with a copolymer (C) obtained by copolymerizing at least one kind (B2) (hereinafter referred to as monomer (C2) for convenience) selected from the monomers represented by . Use of the copolymer (C) in some cases is effective in improving and stabilizing concrete strength.

Specific examples of the monomer (C1) include the aforementioned monomers
Those exemplified in (A1) can be mentioned. Examples of the monomer (C2) include those exemplified for the monomer (B2).

In the copolymer (C), the average weight ratio of the monomer (C2) to all the monomers for producing the copolymer (Z
It is preferred that _I ) is 1 to 30 (% by weight). The average weight ratio is represented by [total amount of monomer (C2) / total amount of monomer] × 100 (% by weight). Hereinafter, this average weight ratio is referred to as “(C2)
Average weight ratio ". In the present invention, a copolymer (C ′) produced at an average weight ratio (Z _II ) different from the (C2) average weight ratio of the copolymer (C) may be used in combination. The copolymers (C) and (C ′) are preferably selected such that the average weight ratios (Z _I ) and (Z _II ) differ by one or more. The copolymers (C) and (C ′) may be the same or different in the type of the monomers (C1) and (C2) used in the production, but the same type may be used. It is preferably used. In the monomer (C1),
In the general formula (b1), r is 110 or more and 300 or less, and r is preferably 200 or less, more preferably 150 or less, and particularly preferably 130 or less from the viewpoint of polymerizability. The amount of the copolymer (C) may be appropriately determined in consideration of the amounts of the copolymer mixture (A) and the copolymer (B), but when the feature of the component (A) is mainly used, , [(C) /
[(A) + (C)]] × 100 is preferably more than 0 and less than 50 (% by weight), more preferably more than 0 and less than 30 (% by weight), more preferably more than 0 and less than 20 (% by weight). Further, taking into account the mutual effect of the copolymer mixture (A) and the copolymer (C) [(A) /
[(A) + (C)]] × 100 can be used in a ratio of more than 0 and less than 50 (% by weight), and in this case, more preferably more than 0 and less than 30 (% by weight), and more preferably more than 0 and less than 20 (% by weight). (% By weight).

[0064] 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 agents such as alkyl (phenyl) ether phosphate (salt), protein material, alkenyl succinic acid, α-olefin sulfonate; gluconic acid, glucoheptonic acid, arabonic acid, malic acid,
Oxycarboxylic acids such as citric acid, dextrins, monosaccharides, oligosaccharides, sugars such as polysaccharides, sugar alcohols and other retarders; foaming agents; thickeners; silica sand; AE water reducing agents; Soluble calcium salts such as calcium nitrate, calcium nitrate, calcium bromide and calcium iodide, chlorides such as iron chloride and magnesium chloride, sulfate, potassium hydroxide, sodium hydroxide, carbonate, thiosulfate, formic acid ( Salts), alkanolamines and other early-strength agents or accelerators; blowing agents; waterproofing agents such as resin acids (salts), fatty acid esters, oils and fats, silicone, paraffin, asphalt and wax;
Blast furnace slag; fluidizer; dimethylpolysiloxane-based, polyalkylene glycol fatty acid ester-based, mineral oil-based, oil-based, oxyalkylene-based, alcohol-based, amide-based defoamer; antifoamer; fly ash; melamine sulfonic acid High-performance water reducing agents such as formalin condensate, aminosulfonic acid, polycarboxylic acid, and polymaleic acid; silica fume; rust inhibitors such as nitrite, phosphate, zinc oxide; cellulose based such as methylcellulose and hydroxyethylcellulose , Β-1,3-glucan, xanthan gum and the like, and synthetic systems such as polyacrylamide, polyethylene glycol, ethylene oxide adduct of oleyl alcohol or a reaction product thereof with vinylcyclohexene diepoxide, and the like. Molecule; high content of alkyl (meth) acrylate Emulsions and the like.

The cement dispersant of the present invention can be used not only in the fields of ready-mixed concrete and concrete vibration products, but also for self-leveling, refractory, plaster, gypsum slurry, lightweight or heavy concrete, AE, repair, prepacked 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.

[0066]

EXAMPLES <Copolymer mixture (A)> A copolymer mixture shown in Table 1 was produced. At that time, the molar ratio of the monomers (A1) and (A2)
(A1) / (A2) was changed during the reaction.

[0067]

[Table 1]

(Note) In Table 1, MPEGMM is an abbreviation for methoxypolyethylene glycol monomethacrylate.
The numbers in parentheses are the average number of moles of ethylene oxide added (the same applies hereinafter). MAA is methacrylic acid (the same applies hereinafter).

<Copolymer (B)> A copolymer shown in Table 2 was produced. At that time, the weight ratio of the monomers (B1) and (B2) was kept constant.

[0070]

[Table 2]

<Copolymer (C)> A copolymer shown in Table 3 was produced. At that time, the weight ratio of the monomers (C1) and (C2) was kept constant.

[0072]

[Table 3]

<Concrete test conditions> (1) Material W = tap water C = ordinary Portland cement (specific gravity = 3.16) Fine aggregate = Kimitsu from Kanto (specific gravity = 2.63) Coarse aggregate = Ibaraki crushed bone (specific gravity = 2.62) W / C = (unit weight of W / unit weight of C) × 100% s / a = [fine aggregate volume / (fine aggregate volume + coarse aggregate volume)]
× 100% (2) Composition Table 4 shows the composition of the concrete prepared from the above materials.

[0074]

[Table 4]

(3) Kneading conditions Material and dispersant for 30 liters of concrete are put into a forced twin-screw mixer (50 liters), kneaded for 90 seconds, and the performance immediately after discharge (initial slump value) is measured. The slump test was performed according to JIS-A1101.

(4) Curing conditions The discharged concrete is placed in a compression test form (specimen diameter 10 mm).
cm, specimen height 20 cm), and leave it at room temperature for 30 minutes.
Steam curing was performed at 65 ° C for 4 hours. 1 hour 20 after steam curing
After standing at 0 ° C, the compressive strength of the test specimen is measured. The compressive strength was measured according to JIS-A1132 / A1108.

(5) Test method Tests were conducted at a room temperature of 20 ° C. for the concrete formulations shown in Table 4.
Dispersibility, retention and viscosity were measured by the following methods. The results are shown in Tables 5 to 8. Dispersibility: The rate of addition of the dispersant solid to the total powder required for the initial slump value to be 8 ± 1 cm. The smaller the number,
Good dispersibility. Retention: Percentage of slump value after 30 minutes to initial slump value. The larger the value, the better the dispersion retention. Viscosity: For concrete blocks with slump cones removed,
After measuring the initial slump value, measuring the maximum extent L ₁ of the bottom of the concrete mass. A slump test rod is vertically dropped from the iron plate along the length from the iron plate to the iron plate on which the concrete mass is placed. This measures the maximum broadening L ₂ of the bottom of the concrete mass after repeating 10 times. viscosity
C is calculated as C = (L ₂ / L ₁ ) × 100 (%). The larger the C, the lower the viscosity.

[0078]

[Table 5]

[0079]

[Table 6]

[0080]

[Table 7]

[0081]

[Table 8]

(Explanation) From Comparative Examples 1-1 and 1-2, it is understood that the viscosity increases even when the copolymer (C) is used in combination with the copolymer mixture (A).

From Examples 1-1 to 1-6, the copolymer mixture (A)
It can be seen that when the copolymer (B) is used in combination, the dispersibility and the compressive strength are the same and the viscosity can be reduced. For maintaining the compressive strength, the general formula (b1) of the raw material monomer (B1) of the copolymer (B)
It is preferable that r therein is 75 or more.

Comparative Examples 2-1 to 4-2 (Tables 6 to 8) and Example 2-
From 1 to 4-2 (Tables 6 to 8), it can be seen that when the copolymer (B) is used in combination with the copolymer mixture (A), the viscosity can be reduced without significantly changing other performances. In particular, from Examples 3-3 and 3-4,
Further, it is found that the use of the copolymer (C) in these systems is more preferable because the compressive strength becomes more stable. Further, particularly from Comparative Examples 4-1 and 4-2 and Examples 4-1 and 4-2, when the copolymer mixture (A) is used in combination with a system mainly containing the copolymer (B), It can be seen that the retention can be improved without significantly changing.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C08F 222/04 C08F 222/04 290/06 290/06 C08L 55/00 C08L 55/00 // C04B 103: 40 C04B 103 : 40 (72) Inventor Wataru Mizuno 1334 Minato, Wakayama, Wakayama Pref., Kao Co., Ltd. (72) Inventor Miaki Tanisho, 1334 Minato, Wakayama, Wakayama Pref., Kao Co., Ltd. 1334 Minato, Wakayama-shi, Japan F-term in Kao Research Institute (Reference)

Claims (6)

[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 (A) obtained by copolymerization, wherein the molar ratio (A1) / (A2) of the monomers (A1) and (A2) is changed at least once during the reaction.
And at least one of the monomers represented by the following general formula (b1) (B
1) and at least one selected from a monomer represented by the following general formula (b2-1) and a monomer represented by the following general formula (b2-2)
A cement dispersant comprising a copolymer (B) obtained by copolymerizing a seed (B2). 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. ) (Wherein, R ⁷ , R ⁸ : hydrogen atom or methyl group R ⁹ : alkylene group having 2 to 3 carbon atoms R ¹⁰ : hydrogen atom or alkyl group having 1 to 3 carbon atoms q: the number of 0 to 2 r: 50 And represents a number less than 110.) (Wherein, R ^{11 to} R ^{13 are a} hydrogen atom, a methyl group or (CH ₂ ) _s COOM ⁴ , and (CH ₂ ) _s COOM ⁴ is an anhydride of COOM ³ or another (CH ₂ ) _s COOM ⁴ May be formed, in which case M ³ , M ⁴
Does not exist. R ¹⁴ : hydrogen atom or methyl group M ³ , M ⁴ , Y: hydrogen atom, alkali metal, alkaline earth metal, ammonium group, alkylammonium group or substituted alkylammonium group s: represents the number of 0 to 2. ) 2. A copolymer of at least one kind of monomer represented by the general formula (a1) (A1) and at least one kind of monomer represented by the general formula (a2) (A2) A copolymer mixture wherein the molar ratio (A1) / (A2) of the monomers (A1) and (A2) is changed at least once in the course of the reaction, wherein the copolymer The average weight ratio (X _II ) of the monomer (A2) to all the monomers for producing the mixture is the same as the monomer (A2) for all the monomers for producing the copolymer mixture (A). 2. The cement dispersant according to claim 1, which contains a copolymer mixture (A ′) different from the average weight ratio (X _I ) of (1). 3. The average weight ratio (X _I ) and (X _II ) are each 1
3. The cement dispersant according to claim 2, wherein the amount is in the range of about 30 to 30% by weight. 4. A copolymer of at least one kind of monomer represented by the general formula (b1) (B1) and at least one kind of monomer represented by the general formula (b2) (B1) The copolymer obtained by the above, the average weight ratio of the monomer (B2) to all monomers for producing the copolymer (Y _II ), the copolymer (B) is produced Weight ratio of monomer (B2) to all monomers
(Y _I) any one of claims cement dispersant of claim 1 containing different copolymer (B ') and. 5. An average weight ratio (Y _I ) and (Y _II ) of 1
The cement dispersant according to claim 4, wherein the amount is in the range of ~ 30 (% by weight). 6. The weight ratio of the copolymer (B) to the total of the copolymer mixture (A) and the copolymer (B) is more than 0 and less than 50 (% by weight).
Or the copolymer mixture (A) of the copolymer mixture (A)
The cement dispersant according to any one of claims 1 to 5, wherein the weight ratio to the total of the copolymer and the copolymer (B) is more than 0 and less than 50 (% by weight).