JP3180864B2 - Cement dispersant and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cement dispersant and a method for producing the same. More specifically, cement paste, mortar, and concrete, such as concrete, improve the dispersibility of cement particles to increase the fluidity of the cement composition, and prevent the obtained fluidity from decreasing over time, Also, the present invention relates to a cement dispersant which gives a cement composition good workability and hardened material strength by entraining an appropriate amount of air, and a method for producing the same.

[0002]

2. Description of the Related Art Since the early deterioration of concrete structures became a social problem in 1981, there has been a strong demand for reducing the amount of water in concrete to improve its workability and durability. Technical innovations on cement dispersants, which greatly affect the quality and performance of cement, have been actively pursued.

[0003] As a conventional method of improving workability, a ready-mixed concrete with a low fluidity (hereinafter referred to as "slump") to which an AE water reducing agent is added is manufactured in a plant and transported to a casting site by a ready-mixed concrete truck. A fluidizing method has been adopted in which a fluidizing agent is added to the fluidized material to fluidize the fluidized material so as to increase the slump to a predetermined value. However, this method uses a ready-mixed concrete car to add a fluidizer to concrete and stir and mix it.
Various problems such as noise and exhaust gas generated at this time, responsibility for the quality of the obtained fluidized concrete, and extreme decrease in fluidity of the fluidized concrete with time (hereinafter referred to as "slump loss"). was there.

[0004] Therefore, each admixture maker has been vigorously developing a so-called high-performance AE water reducing agent which has a high water reducing property and an extremely small slump loss and which can be added in a raw conplant. Acids and polycarboxylic acids are commercially available. Among them, the polycarboxylic acid-based high-performance AE water reducing agent has an excellent feature that it has a high water reducing property and can also prevent slump loss, but has a drawback that the amount of air entrained in concrete tends to increase. As a result, there is a case where stable predetermined concrete strength cannot be obtained. Therefore, a method of blending various antifoaming agents with a polycarboxylic acid-based high-performance AE water reducing agent has been proposed. For example, JP-A-63-15
Japanese Patent No. 6049 proposes a copolymer compound containing propylene oxide and ethylene oxide as main components as an antifoaming agent, and Japanese Patent Application Laid-Open No. 4-119555 discloses a block copolymer with ethylene oxide containing propylene oxide at both ends. Copolymers have been proposed. However, since the antifoaming agent is essentially water-insoluble, the conventional method using a mixture of a polycarboxylic acid-based high-performance AE water reducing agent and an antifoaming agent has poor storage stability of the mixture, and the antifoaming agent is separated. When this mixture is used for concrete, it is difficult to adjust the amount of entrained air when the mixture is used for concrete, and there is a problem that a stable predetermined slump cannot be obtained and the workability and the strength of concrete are reduced.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a polycarboxylic acid-based high-performance AE water reducing agent which has a high water reducing property and prevents slump loss, and has excellent storage stability. An object of the present invention is to provide a cement dispersant capable of stably imparting a predetermined strength to a cement composition because an appropriate amount of air can be entrained in the cement composition, and a method for producing the same.

[0006]

The above objects are attained by a cement comprising an aqueous composition containing at least one of the following copolymers (A) to (C) as a main component. Dispersant.

The following general formula (1)

[0008]

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(Wherein, R ¹ and R ² each independently represent hydrogen or a methyl group, and R ³ has 2 to 2 carbon atoms)
4 represents an alkylene group, wherein R ⁴ is hydrogen or
Represents an alkyl group of 22; m represents an integer of 1 to 100; (Alkoxy) polyalkylene glycol mono (meth) acrylate monomer (a) 5
0 to 97% by weight, the following general formula (2)

[0010]

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(Wherein, R ¹ and R ² each independently represent hydrogen or a methyl group, and M ¹ represents hydrogen, a monovalent metal, a divalent metal, an ammonium group or an organic amine group). (Meth) acrylic acid monomer (b)
3 to 50% by weight and other monomers copolymerizable with these monomers (c) 0 to 30 % by weight (provided that (a),
The sum of (b) and (c) is 100% by weight. ), An unsaturated carboxylic acid-based monomer having a monomer mixture (III) comprising the oxylalkylene-based antifoaming agent (I)
Copolymer (A) obtained by polymerization in the presence of I), copolymer (B) obtained by further neutralizing copolymer (A) with an alkaline substance, and copolymer (A) Is further achieved by a cross-linked copolymer (C) obtained by post-cross-linking using a cross-linking agent.

The above-mentioned objects are to provide a cement dispersant comprising an aqueous composition containing at least one of the following copolymers (A) to (C) as a main component.

The following general formula (3)

[0014]

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(Wherein, R ¹ and R ² each independently represent hydrogen or a methyl group, and R ³ has 2 to 2 carbon atoms)
4 represents an alkylene group, wherein R ⁴ is hydrogen or
22 represents an alkyl group, n represents an integer of 0 or 1, and m represents an integer of 1 to 100. (50) to 97% by weight of an (alkoxy) polyalkylene glycol mono (meth) allyl ether-based monomer (d) represented by the following general formula (4)

[0016]

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(Wherein, X and Y each independently represent hydrogen, a methyl group or —COOM ² , and Z represents —
CH ₂ COOM ² , hydrogen or methyl, wherein at least two of X, Y and Z are hydrogen or methyl, and M ¹ and M ² are hydrogen, monovalent metal, divalent metal, ammonium Group, organic amine group, carbon number 1-20
Or an alkylene glycol having 2 to 4 carbon atoms or an addition mole number of 2 to 100 of these glycols
Wherein M ¹ or M ^1
At least one of ² is hydrogen, a monovalent metal, a divalent metal, an ammonium group, or an organic amine group. Also, the general formula (4)
Is an unsaturated dicarboxylic acid, the anhydride thereof is also included) 3 to 50% by weight of an unsaturated carboxylic acid monomer (e) represented by
And a monomer composed of 0 to 30 % by weight of other monomers (f) copolymerizable with these monomers (the total of (d), (e) and (f) is 100% by weight). (A) obtained by polymerizing an unsaturated carboxylic acid-based monomer containing a monomer mixture (III) as an essential component in the presence of an oxylalkylene-based antifoaming agent (II); A copolymer (B) obtained by further neutralizing A) with an alkaline substance, and a crosslinked copolymer (C) obtained by post-crosslinking the copolymer (A) using a crosslinking agent.

A copolymer (A) obtained by polymerizing a monomer mixture (III) containing an unsaturated carboxylic acid monomer as an essential component in the presence of an oxyalkylene antifoaming agent (II);
The copolymer (B) obtained by further neutralizing the copolymer (A) with an alkaline substance and the crosslinked copolymer obtained by post-crosslinking the copolymer (A) using a crosslinking agent ( C)
Is also achieved by

The above objects are achieved by the following general formula (1) in the presence of an oxyalkylene-based antifoaming agent.

[0020]

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(Wherein, R ¹ and R ² each independently represent hydrogen or a methyl group, and R ³ has 2 to 2 carbon atoms)
4 represents an alkylene group, wherein R ⁴ is hydrogen or
Represents an alkyl group of 22; m represents an integer of 1 to 100; (Alkoxy) polyalkylene glycol mono (meth) acrylate monomer (a) 5
0 to 97% by weight, the following general formula (2)

[0022]

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(Wherein, R ¹ and R ² each independently represent hydrogen or a methyl group, and M ¹ represents hydrogen, a monovalent metal, a divalent metal, an ammonium group or an organic amine group). (Meth) acrylic acid monomer (b)
3 to 50% by weight and other monomers copolymerizable with these monomers (c) 0 to 30 % by weight (provided that (a),
The sum of (b) and (c) is 100% by weight. ) Is obtained by polymerizing an unsaturated carboxylic acid-based monomer having a monomer mixture (III) comprising the essential component as the essential component.

The above objects are achieved by the following general formula (3) in the presence of an oxyalkylene-based antifoaming agent.

[0025]

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(Wherein, R ¹ and R ² each independently represent hydrogen or a methyl group, and R ³ has 2 to 2 carbon atoms)
4 represents an alkylene group, wherein R ⁴ is hydrogen or
22 represents an alkyl group, n represents an integer of 0 or 1, and m represents an integer of 1 to 100. (50) to 97% by weight of an (alkoxy) polyalkylene glycol mono (meth) allyl ether-based monomer (d) represented by the following general formula (4)

[0027]

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(Wherein, X and Y each independently represent hydrogen, a methyl group or —COOM ² , and Z represents —
CH ² COOM ² , hydrogen or methyl, wherein at least two of X, Y and Z are hydrogen or methyl, and M ¹ and M ² are hydrogen, monovalent metal, divalent metal, ammonium Group, organic amine group, carbon number 1-20
Or an alkylene glycol having 2 to 4 carbon atoms or an addition mole number of 2 to 100 of these glycols
Wherein M ¹ and M ²
Is hydrogen, a monovalent metal, a divalent metal, an ammonium group, or an organic amine group. In addition, when the general formula (4) is an unsaturated dicarboxylic acid, its anhydride is also included) 3 to 50% by weight of an unsaturated carboxylic acid-based monomer (e) represented by A monomer mixture (III) consisting of 0 to 30 % by weight of other possible monomers (f) (wherein the sum of (d), (e) and (f) is 100% by weight) The present invention is also achieved by a method for producing an aqueous cement dispersant, which comprises polymerizing an ethylenically unsaturated carboxylic acid-based monomer.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION The polycarboxylic acid-based dispersant is a copolymer (A) obtained by polymerizing a monomer mixture (III) containing an unsaturated carboxylic acid-based monomer as an essential component and / or Alternatively, a copolymer (B) obtained by further neutralizing the copolymer (A) with an alkaline substance and / or a crosslinked copolymer obtained by post-crosslinking the copolymer (A) using a crosslinking agent. It is a general term for a cement dispersant containing a polymer (C) as a main component. Here, the unsaturated carboxylic acid monomers include unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid, and monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts thereof; maleic acid, fumaric acid, Unsaturated dicarboxylic acids such as citraconic acid and itaconic acid and their monovalent metal salts, divalent metal salts, ammonium salts, organic amine salts, anhydrides or these acids and aliphatic alcohols having 1 to 20 carbon atoms or carbon atoms Monoesters of 2 to 4 glycols or polyalkylene glycols having an addition mole number of 2 to 100 of these glycols can be mentioned, and one or more of these can be used.

The monomer mixture (III) may comprise 50 to 97% by weight of an (alkoxy) polyalkylene glycol mono (meth) acrylate monomer (a) represented by the general formula (1). 3 to 50% by weight of a (meth) acrylic acid monomer (b) represented by the general formula (2) and a monomer (c) 0 copolymerizable with these monomers.
To 30 wt% (provided that, (a), (b) and total 100% by weight of (c)) mixtures consisting of; represented by the following general formula (3) (alkoxy) polyalkylene glycol mono (meth) allyl ether System monomer (d) 50 to
97% by weight, 3 to 50% by weight of the unsaturated carboxylic acid monomer (e) represented by the general formula (4), and other monomers (f) 0 to 10 copolymerizable with these monomers. 30 % by weight
(However, the sum of (d), (e) and (f) is 100
% By weight).

The monomer (a) used in the present invention is represented by the above general formula. Examples of the monomer (a) include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polybutylene glycol mono (meth) acrylate, Polyethylene glycol polypropylene glycol mono (meth) acrylate,
Polyethylene glycol polybutylene glycol mono (meth) acrylate, polypropylene glycol polybutylene glycol mono (meth) acrylate, polyethylene glycol polypropylene glycol polybutylene glycol mono (meth) acrylate, methoxypolyethylene glycol mono (meth) acrylate, methoxy polypropylene glycol mono (meth) A) acrylate, methoxypolybutylene glycol mono (meth) acrylate, methoxypolyethylene glycol polypropylene glycol mono (meth) acrylate, methoxypolyethylene glycol polybutylene glycol mono (meth) acrylate, methoxypolypropylene glycol polybutylene glycol mono (meth) acrylate, methoxypolyethylene The Call polypropylene glycol polybutylene glycol mono (meth) acrylate,
Ethoxy polyethylene glycol mono (meth) acrylate, ethoxy polypropylene glycol mono (meth)
Acrylate, ethoxy polybutylene glycol mono (meth) acrylate, ethoxy polyethylene glycol polypropylene glycol mono (meth) acrylate, ethoxy polyethylene glycol polybutylene glycol mono (meth) acrylate, ethoxy polypropylene glycol polybutylene glycol mono (meth) acrylate, ethoxy polyethylene glycol Polypropylene glycol polybutylene glycol mono (meth)
Acrylate and the like can be mentioned, and one or more of these can be used.

The monomer (b) is represented by the above general formula. Examples of the monomer (b) include acrylic acid, methacrylic acid and their monovalent metal salts, divalent metal salts,
Mention may be made of ammonium salts and organic amine salts.

The monomer (c) is a monomer copolymerizable with the monomers (a) and (b). Examples of the monomer (c) include esters of aliphatic alcohols having 1 to 20 carbon atoms with (meth) acrylic acid; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and citraconic acid; Monoesters or diesters of aliphatic alcohols having 1 to 20 carbon atoms or glycols having 2 to 4 carbon atoms or polyalkylene glycols having 2 to 100 moles of these glycols added; (meth) acrylamide, (meth) acrylamide Unsaturated amides such as acrylalkylamide; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyls such as styrene; vinyl sulfonic acid, (meth) allyl sulfonic acid, sulfoethyl (meth) acrylate, 2-methyl Propanesulfonic acid (meth) acrylamide, styrenesulfonic acid, etc. Sum sulfonic acids and their monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts and the like, can be used alone or in combination of two or more thereof.

Examples of the monomer (d) include polyethylene glycol mono (meth) allyl ether, polypropylene glycol mono (meth) allyl ether, polybutylene glycol mono (meth) allyl ether, and polyethylene glycol polypropylene glycol mono (meth) Allyl ether, polyethylene glycol polybutylene glycol mono (meth) allyl ether, polypropylene glycol polybutylene glycol mono (meth) allyl ether, polyethylene glycol polypropylene glycol polybutylene glycol mono (meth) allyl ether, methoxypolyethylene glycol mono (meth) allyl ether , Methoxypolypropylene glycol mono (meth) allyl ether, methoxypolybutylene glycol mono (meth) Ryl ether, methoxypolyethylene glycol polypropylene glycol mono (meth) allyl ether, methoxypolyethylene glycol polybutylene glycol mono (meth) allyl ether, methoxypolypropylene glycol polybutylene glycol mono (meth) allyl ether, methoxypolyethylene glycol polypropylene glycol polybutylene glycol mono ( (Meth) allyl ether, ethoxy polyethylene glycol mono (meth) allyl ether, ethoxy polypropylene glycol mono (meth) allyl ether, ethoxy polybutylene glycol mono (meth) allyl ether, ethoxy polyethylene glycol polypropylene glycol mono (meth) allyl ether, ethoxy polyethylene Glycol polybutylene Alkoxy polyalkylene glycol mono (meth) allyl ether such as coal mono (meth) allyl ether, ethoxy polypropylene glycol polybutylene glycol mono (meth) allyl ether, ethoxy polyethylene glycol polypropylene glycol polybutylene glycol mono (meth) allyl ether, polyethylene Glycol monotyl ether, polypropylene glycol monotyl ether, polybutylene glycol monotyl ether, polyethylene glycol polypropylene glycol monotyl ether, polyethylene glycol polybutylene glycol monotyl ether, polypropylene glycol polybutylene glycol monotyl ether, polyethylene glycol polypropylene glycol Polybutylene glycol monochlorotyl ether,
Methoxypolyethylene glycol monobutyl ether, methoxy polypropylene glycol monotyl ether, methoxy polybutylene glycol monotyl ether, methoxy polyethylene glycol polypropylene glycol monotyl ether, methoxy polyethylene glycol polybutylene glycol monotyl ether, methoxypolypropylene glycol polybutylene glycol monotyl ether , Methoxypolyethylene glycol, polypropylene glycol, polybutylene glycol, monochlorotyl ether, ethoxy polyethylene glycol, monochlorotyl ether, ethoxy polypropylene glycol, monochlorotyl ether, ethoxy polybutylene glycol, monochlorotyl ether, ethoxy polyethylene glycol Alkoxy polyalkylene glycol monotyl ethers such as propylene glycol monobutyl ether, ethoxy polyethylene glycol polybutylene glycol monotyl ether, ethoxy polypropylene glycol polybutylene glycol monotyl ether, and ethoxy polyethylene glycol polypropylene glycol polybutylene glycol monotyl ether. And one or more of these can be used.

Examples of the monomer (e) include acrylic acid,
Unsaturated monocarboxylic acids such as methacrylic acid and the like, and monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts thereof; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, and itaconic acid; Valent metal salts, divalent metal salts, ammonium salts, organic amine salts, anhydrides, or acids and aliphatic alcohols having 1 to 20 carbon atoms or glycols having 2 to 4 carbon atoms, or moles of addition of these glycols Monoesters with polyalkylene glycol of several to 100 can be mentioned, and one or more of these can be used.

Examples of the monomer (f) include those having 1 to 2 carbon atoms.
Esters of zero aliphatic alcohols with (meth) acrylic acid; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid and aliphatic alcohols having 1 to 20 carbon atoms or glycols having 2 to 4 carbon atoms or Diesters of these glycols with polyalkylene glycols having 2 to 100 moles of addition; unsaturated amides such as (meth) acrylamide and (meth) acrylalkylamide; vinyl esters such as vinyl acetate and vinyl propionate; Aromatic vinyls: vinyl sulfonic acid, (meth) allyl sulfonic acid, sulfoethyl (meth)
Acrylate, 2-methylpropanesulfonic acid (meth)
Acrylamide, unsaturated sulfonic acids such as styrenesulfonic acid and monovalent metal salts thereof, divalent metal salts, ammonium salts, organic amine salts and the like,
One or more of these can be used.

Examples of the oxyalkylene antifoaming agent (II) include polyoxyalkylenes such as (poly) oxyethylene (poly) oxypropylene adduct; diethylene glycol heptyl ether, polyoxyethylene oleyl ether, and polyoxypropylene butyl ether. ,
(Poly) oxyalkyl ethers such as polyoxyethylene polyoxypropylene 2-ethylhexyl ether and oxyethyleneoxypropylene adducts to higher alcohols having 12 to 14 carbon atoms; polyoxypropylene phenyl ether, polyoxyethylene nonyl phenyl ether and the like (Poly) oxyalkylene (alkyl)
Aryl ethers; 2,4,7,9-tetramethyl-
5-decyne-4,7-diol, 2,5-dimethyl-3
Acetylene ethers obtained by addition-polymerizing an alkylene oxide to acetylene alcohol such as -hexyne-2,5-diol, 3-methyl-1-butyn-3-ol; (polyethylene glycol oleate, ethylene glycol distearate, etc.) ) Oxyalkylene fatty acid esters; (poly) oxyalkylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate and polyoxyethylene sorbitan trioleate; sodium polyoxypropylene methyl ether sulfate, polyoxyethylene dodecyl phenol ether sulfate (Poly) oxyalkylene alkyl (aryl) ether sulfates such as sodium salt; (poly) oxyethylene stearyl phosphate Which (poly) oxyalkylene alkyl phosphoric acid esters; polyoxyethylene such as polyoxyethylene lauryl amine (poly) oxyalkylene alkyl amines and the like, may be used alone or two or more thereof.

The method for adjusting the particle size of the antifoaming agent in the present invention is not particularly limited as long as the particle size of the antifoaming agent can be adjusted to 20 μm or less. For example, there is a method of polymerizing a cement dispersant in the presence of an antifoaming agent, and the resulting cement dispersant is useful in terms of its versatility, workability, and performance. In this case, the obtained cement dispersant (aqueous composition) needs to be stable for at least 24 hours in a static state. If the stability is less than 24 hours, the antifoaming agent tends to be unevenly mixed into the concrete composition, so that air is locally removed or bubbles are coarsened. Such instability of the bubble distribution has an adverse effect on the fluidity and strength of the concrete, so that stable fluidity and strength cannot be obtained.

Although the above method is effective for any kind of cement dispersant, it is not effective for polycarboxylic acid type cement dispersant which has a drawback that the amount of air entrained in concrete tends to increase. Especially effective.

The copolymer (A) is obtained by polymerizing a monomer mixture (III) containing an unsaturated carboxylic acid monomer as an essential component in the presence of the antifoaming agent (II). is there. The compounding ratio of the unsaturated carboxylic acid monomer in the monomer mixture (III) is preferably in the range of 2 to 95% by weight.
When the monomer mixture (III) comprises the aforementioned (d), (e) and (f), 3 to 50% by weight of the monomer mixture (III) ranges from 3 to 50% by weight. More preferably, it is within the range. If the ratio is out of this range, a desired cement dispersant having excellent performance cannot be obtained.

In order to produce the copolymer (A), the monomer mixture (III) may be copolymerized using a polymerization initiator in the presence of the antifoaming agent (II). Defoamer (I
The amount of I) to be used is 0.1 to the monomer mixture (III).
The range is from 01 to 10% by weight, preferably from 0.05 to 5% by weight. If the amount of the antifoaming agent (II) used is less than 0.01% by weight, it is difficult to adjust the amount of entrained air to the cement composition, and a cement composition having stable strength cannot be obtained. If the amount of the antifoaming agent (II) used exceeds 10% by weight, the performance of the resulting cement dispersant is reduced, and a cement composition having good fluidity cannot be obtained.

The polymerization for synthesizing the copolymer (A) is as follows:
It can be carried out by a method such as polymerization in a solvent or bulk polymerization without using a solvent.

The polymerization in the solvent can be carried out batchwise or continuously, with the solvent used being water;
Alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol; aromatic or aliphatic hydrocarbons such as benzene, toluene, xylene, cyclohexane and n-hexane; ester compounds such as ethyl acetate; ketone compounds such as acetone and methyl ethyl ketone. Can be From the solubility of the raw material monomer and the obtained copolymer (A) and the convenience at the time of using the copolymer (A), at least one selected from the group consisting of water and a lower alcohol having 1 to 4 carbon atoms. It is preferable to use one kind. In that case, methyl alcohol, ethyl alcohol, and isopropyl alcohol are particularly effective among the lower alcohols having 1 to 4 carbon atoms.

When the polymerization is carried out in water, a water-soluble polymerization initiator such as an ammonium or alkali metal persulfate or an azoamidine compound such as hydrogen peroxide: azobis-2-methylpropionamidine hydrochloride is used as the polymerization initiator. used. At this time, an accelerator such as sodium hydrogen sulfite can be used in combination. Also, lower alcohols,
For polymerization using an aromatic hydrocarbon, an aliphatic hydrocarbon, an ester compound or a ketone compound as a solvent, peroxides such as benzoyl peroxide and lauroyl peroxide; hydroperoxides such as cumene hydroperoxide; azobisisobutyronitrile And the like are used as polymerization initiators. In this case, an accelerator such as an amine compound may be used in combination. Further, when a water-lower alcohol mixed solvent is used, it can be appropriately selected from the above-mentioned various polymerization initiators or a combination of the polymerization initiator and the accelerator.
The polymerization temperature is appropriately determined depending on the solvent and the polymerization initiator used, but is usually in the range of 0 to 120 ° C.

In the bulk polymerization, a peroxide such as benzoyl peroxide or lauroyl peroxide; a hydroperoxide such as cumene hydroperoxide; an aliphatic azo compound such as azobisisobutyronitrile is used as a polymerization initiator. It is performed within a temperature range of 200 ° C.

The copolymer (A) thus obtained
Is used as a main component of the cement dispersant as it is, but is obtained by post-crosslinking using a copolymer (B) obtained by further neutralizing with an alkaline substance and / or a crosslinking agent, if necessary. The crosslinked copolymer (C) may be used as a main component of the cement dispersant. Such alkaline substances include monovalent metal and divalent metal hydroxides,
Preferred are inorganic salts such as chlorides and carbonates; ammonia; organic amines and the like. The crosslinking agent is not particularly limited as long as it is a compound capable of reacting with a functional group (a carboxyl group, a hydroxyl group, an amino group, a sulfonic acid group, etc.) of the copolymer (A).

[0047]

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A crosslinking agent which has at least one of the divalent groups represented by the formula (1) as a constituent unit and / or can be formed is preferred.

Examples of these crosslinking agents include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol polyglycidyl ether, diglycerol diglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, and pentaerythritol polyether. Polyvalent glycidyl compounds such as glycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, resorcin diglycidyl ether, 1,6-hexanediol diglycidyl ether, adivic acid diglycidyl ester, o-phthalic acid diglycidyl ester, etc. Can be mentioned.

The weight average molecular weight of the copolymer (A) used as the cement dispersant of the present invention and the copolymer (A) used as a raw material of the copolymer (B) or the cross-linked copolymer (C) are as follows. Hereinafter, also referred to as average molecular weight)
Is preferably in the range of 500 to 500,000, and the monomer mixture (III) is as described in the above (a),
In the case of consisting of the monomers (b) and (c),
The range of 0 to 500,000 corresponds to the monomer mixture (III).
Is from the monomers (d), (e) and (f) described above, the monomer mixture (III) is in the range of from 500 to 100,000, and the monomer mixture (III) is defined as (g), (h) and ( When it is composed of the monomer of i), it is more preferably in the range of 500 to 100,000. If the weight average molecular weight is less than 500, it is not preferable because the water reducing performance and the slump loss preventing performance of the cement dispersant are reduced. On the other hand, 500,
A weight average molecular weight exceeding 000 is not preferred because the water reducing performance of the cement dispersant decreases.

The copolymer (A) and / or the copolymer (B) and / or the crosslinked copolymer (C) can be used as a cement dispersant in the form of an aqueous solution or an aqueous emulsion. By appropriately adjusting the type and / or amount of the agent (II), air entrainment to a cement compound such as concrete can be arbitrarily adjusted. Further, the copolymer (A) and / or the copolymer (B) and / or the crosslinked copolymer (C) may be used as a main component in combination with another known cement admixture. Such known cement admixtures include, for example, conventional cement dispersants, air entrainers, cement wetting agents, swelling agents, waterproofing agents, retarders, quick-setting agents, water-soluble polymeric substances, thickeners, coagulants Agents, drying shrinkage reducing agents, strength enhancers, curing accelerators and the like.

The cement dispersant of the present invention can be used for hydraulic cements such as portland cement, alumina cement and various mixed cements, and hydraulic materials other than cements such as gypsum.

The cement dispersant of the present invention exerts excellent effects even when added in a small amount as compared with the conventional cement dispersant. For example, when used for mortar or concrete using hydraulic cement, the cement weight of 0.01 to
1.0%, preferably 0.02 to 0.5%, may be added at the time of kneading. This addition brings about various favorable effects such as an increase in slump, a reduction in the amount of water per unit, an increase in strength, and an improvement in durability. If the added amount is less than 0.01%, the performance is insufficient. Conversely, even if a large amount exceeding 1.0% is used, the effect is substantially flattened and disadvantageous in terms of economy.

[0054]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In the examples, unless otherwise specified,% means weight%,
Parts represent parts by weight.

Example 1 for Production of Cement Dispersant (1) 1695 parts of water was charged into a glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube and a reflux condenser, and stirred. The inside of the reaction vessel was purged with nitrogen, and heated to 95 ° C. in a nitrogen atmosphere. Next, 750 parts of methoxypolyethylene glycol monomethacrylate (average number of moles of ethylene oxide added: 10) 750 parts, methacrylic acid 250
Part, Pluronic L- which is an oxyalkylene antifoaming agent
64 (polyoxyethylene-polyoxypropylene adduct manufactured by Asahi Denka Co., Ltd.) and an aqueous monomer solution consisting of 1500 parts of water and a 5% aqueous ammonium persulfate solution 672
And the mixture was added dropwise over 4 hours.
168 parts of a 10% aqueous solution of ammonium persulfate were added dropwise over 1 hour. Thereafter, the temperature was maintained at 95 ° C. for 1 hour to complete the polymerization reaction, thereby obtaining the cement dispersant (1) of the present invention comprising an aqueous solution of a copolymer having an average molecular weight of 35,000.

Examples 2 to 5 for Producing Cement Dispersants (2) to (5) Cement dispersion comprising the copolymer (A) of the present invention produced by performing the same operation as in Example 1 Agent (2)-
Table 1 and Table 2 summarize the contents of (5).

Example 6 for Producing Cement Dispersant (6) In a glass reaction vessel equipped with a thermometer, stirrer, dropping funnel, nitrogen inlet tube and reflux condenser, 349, 6 parts of water, polyethylene glycol (average addition molar number 5 ethylene oxide) 1648 parts monoallyl ether were charged and C ₁₂ ~ ₁₄ oxyethylene oxypropylene adduct 23.2 parts of the alcohol is a poly oxyalkylene antifoaming agent, the reaction under stirring The atmosphere in the vessel was replaced with nitrogen, and 9
Heated to 5 ° C. Next, 687 parts of maleic acid and water 1
A monomer / polymerization initiator mixed aqueous solution consisting of 030 parts and 57.2 parts of ammonium persulfate was added dropwise over 2 hours, and after the completion of the addition, 527 parts of a 5% ammonium persulfate aqueous solution was further added dropwise over 1 hour. Thereafter, the temperature was maintained at 95 ° C. for 1 hour to complete the polymerization reaction, and the average molecular weight was 6,000.
Thus, a cement dispersant (6) of the present invention comprising an aqueous solution of the copolymer No. 0 was obtained.

Example 7 for Producing Cement Dispersant (7) The cement dispersant (1) obtained in Example 1 was added with 50% N
185 parts of aOH aqueous solution is added dropwise to neutralize to pH 8,
The cement dispersant (7) of the present invention was obtained. Examples 8 to 21 for Producing Cement Dispersants (8) to (21) Hereinafter, cement dispersants (8) comprising the copolymer (B) of the present invention produced by performing the same operation as in Example 7 ) To (2)
Table 3 and Table 4 summarize the contents of 1).

Example 22 for Production of Cement Dispersant (22) A glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube and a reflux condenser was prepared in the same manner as in Example 1 except that
5000 parts of a 0% cement dispersant (1) aqueous solution (1000 parts of a pure dispersant) was charged and heated to 95 ° C. with stirring. Next, 35 parts of o-phthalic acid diglycidyl ester were added, and thereafter, the temperature was maintained at 95 ° C. for 3 hours to complete the crosslinking reaction, and the cement dispersant (22) of the present invention comprising an aqueous solution of a cross-linked copolymer was added. ) Got.

Examples 23 to 25 for Production of Cement Dispersants (23) to (25) Cement comprising the crosslinked copolymer (C) of the present invention produced by the same operation as in Example 22 Dispersant (2
Table 5 summarizes the contents of 3) to (25).

[0061]

[Table 1]

[0062]

[Table 2]

[0063]

[Table 3]

[0064]

[Table 4]

[0065]

[Table 5]

Comparative Example 1 for Producing Comparative Cement Dispersant (1) 1695 parts of water was charged into a glass reactor equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube and a reflux condenser, and stirred. The inside of the reaction vessel was replaced with nitrogen, and heated to 95 ° C. under a nitrogen atmosphere. Next, 4 parts each of an aqueous monomer solution consisting of 800 parts of methoxypolyethylene glycol monoacrylate (average number of moles of ethylene oxide added: 10), 200 parts of methacrylic acid and 1500 parts of water, and 672 parts of a 5% ammonium persulfate aqueous solution were added. After completion of the dropwise addition, 168 parts of a 5% aqueous ammonium persulfate solution were further added dropwise over 1 hour. Thereafter, the temperature was maintained at 95 ° C. for 1 hour, and the polymerization reaction was completed to obtain a comparative cement dispersant (1) comprising an aqueous solution of a copolymer having an average molecular weight of 35,000.

Comparative Example 2 for Production of Comparative Cement Dispersant (2) 1695 parts of water was charged into a glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen inlet tube and a reflux condenser, and stirred. The inside of the reaction vessel was replaced with nitrogen, and heated to 95 ° C. under a nitrogen atmosphere. Next, 800 parts of methoxypolyethylene glycol monoacrylate (average number of added moles of ethylene oxide: 10), 200 parts of methacrylic acid
Parts, 0.005 parts of Pluronic L-64 (a polyoxyethylene-polyoxypropylene adduct manufactured by Asahi Denka Co., Ltd.) which is a polyoxyalkylene-based antifoaming agent and water 15
A monomer aqueous solution consisting of 00 parts and 672 parts of a 5% aqueous solution of ammonium persulfate were added dropwise over 4 hours.
Dropped in time. Subsequently, the temperature was maintained at 95 ° C. for 1 hour to complete the polymerization reaction, and the average molecular weight was 350,000.
Comparative Cement Dispersant Consisting of an Aqueous Copolymer Solution (2)
I got

Comparative Example 3 for Producing Comparative Cement Dispersant (3) If obtained in Comparative Example 1, Comparative Cement Dispersant (1) 100
To 0.1 part of polyoxyethylene polyoxypropylene nonyl phenyl ether, which is a polyalkylene-based defoamer,
The mixture was mixed to obtain a comparative cement dispersant (3).

Comparative Example 4 for Production of Comparative Cement Dispersant (4) In a glass reactor equipped with a thermometer, stirrer, dropping funnel, nitrogen inlet tube and reflux condenser, 349.6 parts of water and polyethylene glycol were added. 1648 parts of monoallyl ether (average number of added moles of ethylene oxide: 5) was charged, and the inside of the reaction vessel was purged with nitrogen under stirring, and then heated to 95 ° C. under a nitrogen atmosphere.
Until heated. Next, 687 parts of maleic acid and 1030 of water
Parts and an aqueous solution of a monomer / polymerization initiator consisting of 57.2 parts of ammonium persulfate were added dropwise over 2 hours, and after the addition was completed, 527 parts of a 5% aqueous solution of ammonium persulfate were added dropwise over 1 hour. Thereafter, the temperature was maintained at 95 ° C. for 1 hour, and the polymerization reaction was completed to obtain a comparative cement dispersant (4) comprising a copolymer aqueous solution having an average molecular weight of 6,000.

Comparative Example 5 for Producing Comparative Cement Dispersant (5) When obtained in Comparative Example 4, Comparative Cement Dispersant (4) 100
Was obtained polyalkylene defoamer is a C ₁₂ ~ ₁₄ oxyethylene oxypropylene adduct 0.1 part mixing and compared cement dispersant to alcohol (5) in section.

[Test of Storage Stability] The particle diameters of the defoamers in the 28 kinds of cement dispersants of the present invention shown in Tables 1 to 5 were measured and the mixture was allowed to stand at 50 ° C. to visually check the degree of compatibility. The storage stability was examined by observing at. For comparison, the comparative cement dispersant (3) obtained in Comparative Example 3 and the comparative cement dispersant (5) obtained in Comparative Example 5 were also tested. The particle size of the defoaming agent was measured using a laser diffraction type particle size analyzer (Microtrac FRA). Tables 6 and 7 show the results. In Tables 6 and 7, the compatibility evaluation is as follows.

：: Uniformly compatible or stably dispersed Δ: Incompatible, separation instability ×: Two-layer separation

[0073]

[Table 6]

[0074]

[Table 7]

[Concrete test] As a cement, ordinary Portland cement (mixing of three brands with equal weight: specific gravity 3.16), and as fine aggregate, mixed sand of Oigawa water based land sand and Kisarazu mountain sand (specific gravity: 2.62, FM2) .
71), Hard sandstone crushed stone (specific gravity 2.64, MS 20 mm) from Ome, Tokyo was used as coarse aggregate.

On the other hand, as a cement dispersant, Tables 1 to 5
And the cement dispersants (1) to (5), naphthalene sulfonic acid formalin condensate (NSF) and melamine sulfonic acid formalin condensate (MSF) for comparison. Using. Here, the comparative cement dispersants (1), (2) and (4) do not adjust the amount of entrained air using the air entraining agent because they have air entraining properties themselves. As for the cement dispersants (1) to (17) of the invention, the comparative cement dispersants (3) and (5), and NSF and MSF, commercially available air entrainers (Pozzolith No. 303A manufactured by NMB Co., Ltd.) are shown in Table 9. The amount of entrained air was adjusted as appropriate using the addition amounts shown in Table 10.

The mixing condition of the plain concrete containing no cement dispersant is that the unit cement amount is 320 kg / m.
³ , unit water volume 203 kg / m ³ (water / cement ratio 63.
4%) and a fine aggregate ratio of 49%.
20 kg / m ³ , unit water amount 166 kg / m ³ (water / cement ratio 51.9%) and fine aggregate ratio 47%.

Concrete was manufactured under the above conditions, and the slump value and the amount of air change over time were measured to evaluate slump loss and air entrainment. The setting time and compressive strength of the 28-day-old concrete were also measured.

The concrete was kneaded using a forced kneading mixer, and the method of measuring slump, air volume, compressive strength and setting time, and the method of collecting the compressive strength specimens were all based on Japanese Industrial Standards (JIS A 1101, 1108, 11
28, 1132, 6204).

The results are shown in Tables 8 to 13.

[0081]

[Table 8]

[0082]

[Table 9]

[0083]

[Table 10]

[0084]

[Table 11]

[0085]

[Table 12]

[0086]

[Table 13]

From Tables 8 and 9, it can be seen that the storage stability of the cement dispersant of the present invention is much improved as compared with the case where a copolymer conventionally used as a cement dispersant is simply mixed with an antifoaming agent. You can see that it is.

Tables 8 to 13 show that the comparative cement dispersants (1) and (4) obtained by polymerization without using an antifoaming agent and the comparative cement dispersant in which the amount of the antifoaming agent used is 0.005%. In the case of the agent (2), the amount of air becomes 4.5 to 5%, the amount to be used is restricted, and the compressive strength of the material on the 28th day is also reduced. Since it has decreased, it can be adjusted to an arbitrary air amount by the air entraining agent. In addition, other physical properties are equal to or higher than those of the comparative concrete, and it can be seen that especially the compressive strength of the 28-day-old material is significantly improved.

Further, while the comparative cement dispersants (3) and (5) in which an antifoaming agent was mixed after the polymerization increased the amount of entrained air with time, the air entrainment of the cement dispersant of the present invention was Stable over time, plain concrete,
It can be seen that slump loss prevention performance is superior to NSF and MSF.

[0090]

Industrial Applicability The cement dispersant of the present invention solves the problems caused by the excessive air entrainment of the conventional polycarboxylic acid-based high-performance AE water reducing agent, and improves the storage stability. Excellent and stable entrainment of air volume. Therefore, according to the cement dispersant of the present invention, it is possible to prepare a cement compound such as concrete having a high water reduction rate and good fluidity, and by hardening the cement compound, a concrete hardened material having high compressive strength can be obtained.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideyuki Tahara 14-1 Chidoricho, Kawasaki-ku, Kawasaki-shi, Kanagawa Japan Co., Ltd. Inside Nippon Shokubai Polymer Research Laboratory (72) Inventor Ken Kenta 14 Chidori-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa 1 Nippon Shokubai Co., Ltd. Polymer Research Laboratory (56) References JP-A-61-141652 (JP, A) JP-A-61-270247 (JP, A) JP-A-59-203745 (JP, A)

Claims (8)

(57) [Claims] 1. A cement dispersant comprising an aqueous composition containing at least one of the following copolymers (A) to (C) as a main component. The following general formula (1) (Wherein, R ¹ and R ² each independently represent hydrogen or a methyl group, R ³ represents an alkylene group having 2 to 4 carbon atoms, and R ⁴ represents hydrogen or an alkyl group having 1 to 22 carbon atoms. And m represents an integer of 1 to 100.) (Alkoxy) polyalkylene glycol mono (meth) acrylate monomer (a) 50 to 97% by weight, the following general formula (2) Formula 2 (Wherein, R ¹ and R ² each independently represent hydrogen or a methyl group, and M ¹ represents hydrogen, a monovalent metal, a divalent metal, an ammonium group, or an organic amine group). 3 to 50% by weight of a (meth) acrylic acid-based monomer (b) and 0 to 30% by weight of another monomer (c) copolymerizable with these monomers (provided that (a) and (b) And (c) is 100% by weight.) An unsaturated carboxylic acid-based monomer having a monomer mixture (III) as an essential component in the presence of an oxylalkylene-based antifoaming agent (II) The copolymer (A) obtained by polymerization, the copolymer (B) obtained by further neutralizing the copolymer (A) with an alkaline substance, and the copolymer (A) further using a crosslinking agent Crosslinked copolymer (C) obtained by post-crosslinking. 2. The amount of said oxyalkylene-based antifoaming agent (II) is 0.01 to 10 with respect to said monomer mixture (III).
2. The cement dispersant according to claim 1, which is in weight%. 3. A cement dispersant comprising an aqueous composition containing at least one of the following copolymers (A) to (C) as a main component. The following general formula (3) (Wherein, R ¹ and R ² each independently represent hydrogen or a methyl group, R ³ represents an alkylene group having 2 to 4 carbon atoms, and R ⁴ represents hydrogen or an alkyl group having 1 to 22 carbon atoms. And n represents an integer of 0 or 1, and m represents 1 to
Represents an integer of 100. (50) to 97% by weight of an (alkoxy) polyalkylene glycol mono (meth) allyl ether-based monomer (d) represented by the following general formula (4): (Wherein, X and Y each independently represent hydrogen, a methyl group or -COOM ² , and Z represents -CH ₂ COO
M ² represents hydrogen or a methyl group, wherein X, Y
And at least two of Z are hydrogen or a methyl group, and M ¹ and M ² are hydrogen, a monovalent metal, a divalent metal, an ammonium group, an organic amine group, an alkyl group having 1 to 20 carbon atoms or 2 to 2 carbon atoms. Represents an alkylene glycol of 4 or a polyalkylene glycol having an addition mole number of 2 to 100 of these glycols, wherein at least one of M ¹ or M ² is hydrogen, a monovalent metal, a divalent metal, an ammonium group, or an organic amine group. . In addition, when the general formula (4) is an unsaturated dicarboxylic acid, its anhydride is also included) 3 to 50% by weight of an unsaturated carboxylic acid-based monomer (e) represented by Other possible monomers (f) 0
30% by weight (wherein the sum of (d), (e) and (f) is 100% by weight)
A copolymer (A) obtained by polymerizing an unsaturated carboxylic acid-based monomer containing I) as an essential component in the presence of an oxylalkylene-based antifoaming agent (II); A copolymer (B) obtained by neutralization with an alkaline substance and a crosslinked copolymer (C) obtained by post-crosslinking the copolymer (A) using a crosslinking agent. A monomer mixture (III) containing an unsaturated carboxylic acid-based monomer as an essential component is converted to an oxyalkylene-based defoamer (I
Copolymer (A) obtained by polymerization in the presence of I), copolymer (B) obtained by further neutralizing copolymer (A) with an alkaline substance, and copolymer (A) Is further post-crosslinked using a crosslinking agent to obtain a crosslinked copolymer (C). 4. The amount of said oxyalkylene-based antifoaming agent (II) is 0.01 to 10 with respect to said monomer mixture (III).
The cement dispersant according to claim 3, which is in weight%. 5. In the presence of an oxyalkylene-based antifoaming agent,
The following general formula (1) (Wherein, R ¹ and R ² each independently represent hydrogen or a methyl group, R ³ represents an alkylene group having 2 to 4 carbon atoms, and R ⁴ represents hydrogen or an alkyl group having 1 to 22 carbon atoms. And m represents an integer of 1 to 100.) (Alkoxy) polyalkylene glycol mono (meth) acrylate monomer (a) 50 to 97% by weight, the following general formula (2) Formula 6 (Wherein, R ¹ and R ² each independently represent hydrogen or a methyl group, and M ¹ represents hydrogen, a monovalent metal, a divalent metal, an ammonium group, or an organic amine group). 3 to 50% by weight of a (meth) acrylic acid-based monomer (b) and 0 to 30% by weight of another monomer (c) copolymerizable with these monomers (provided that (a) and (b) And (c) is 100% by weight.) Production of an aqueous cement dispersant characterized by polymerizing an unsaturated carboxylic acid-based monomer having a monomer mixture (III) consisting of Method. 6. The amount of the oxyalkylene-based antifoaming agent (II) is 0.01 to 10 with respect to the monomer mixture (III).
The method for producing a cement dispersant according to claim 5, wherein the amount is% by weight. 7. In the presence of an oxyalkylene antifoam,
The following general formula (3) (Wherein, R ¹ and R ² each independently represent hydrogen or a methyl group, R ³ represents an alkylene group having 2 to 4 carbon atoms, and R ⁴ represents hydrogen or an alkyl group having 1 to 22 carbon atoms. And n represents an integer of 0 or 1, and m represents 1 to
Represents an integer of 100. (50) to 97% by weight of an (alkoxy) polyalkylene glycol mono (meth) allyl ether-based monomer (d) represented by the following general formula (4): (Wherein, X and Y each independently represent hydrogen, a methyl group or -COOM ² , and Z represents -CH ² COO
M ² represents hydrogen or a methyl group, wherein X, Y
And Z is hydrogen or a methyl group, and M ¹ and M ² are hydrogen, a monovalent metal, a divalent metal, an ammonium group, an organic amine group, an alkyl group having 1 to 20 carbon atoms or 2 to 2 carbon atoms. 4 or a polyalkylene glycol having an addition mole number of 2 to 100 of these glycols, wherein at least one of M ¹ and M ² is hydrogen, a monovalent metal, a divalent metal, an ammonium group,
It is an organic amine group. And (3) to 50% by weight of an unsaturated carboxylic acid monomer (e) represented by the following general formula (4): Other possible monomers (f) 0 to 30
% By weight (where the sum of (d), (e) and (f) is 100% by weight)
A method for producing an aqueous cement dispersant, comprising polymerizing an ethylenically unsaturated carboxylic acid-based monomer containing as an essential component. 8. The amount of the oxyalkylene-based antifoaming agent (II) is 0.01 to 10 with respect to the monomer mixture (III).
The method for producing a cement dispersant according to claim 7, wherein the amount is% by weight.