JP3327809B2 - Cement dispersant, method for dispersing cement and cement composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cement dispersant,
The present invention relates to a cement dispersing method and a cement composition. More particularly, the present invention relates to a cement dispersant, a method for dispersing cement, and a cement composition having excellent water reducing performance, moderate air entrainment, and good slump holding performance.

[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 unit water content in concrete to improve its durability and workability.

Accordingly, it is an object of the present invention to provide a cement dispersant, a method for dispersing cement, and a method for producing a cement composition.

Another object of the present invention is to provide a cement dispersant, a method for dispersing cement, and a cement composition capable of controlling excessive air entrainment while maintaining excellent water reducing performance peculiar to polycarboxylic acids. Is to do.

[0005]

The above objects are achieved by the following (1) to (13).

(1) A cement dispersant containing a polymer obtained by polymerizing a monomer component containing an alkoxypolyalkylene glycol mono (meth) acrylate monomer obtained by a transesterification method.

(2) General formula (1)

[0008]

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(Wherein, R ¹ represents 1 to 2 carbon atoms)
And R ² O represents one or a mixture of two or more oxyalkylene groups having 2 to 4 carbon atoms.
In the case of more than one kind, they may be added in block form or in random form, and m is the average number of moles of oxyalkylene group added and represents a number of 1 to 100. An alkoxypolyalkylene glycol represented by the general formula (2):

[0010]

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(Wherein, R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents an alkyl group having 1 to 22 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms). General formula (3) obtained by subjecting the obtained (meth) acrylic acid ester to a transesterification reaction in the presence of a basic catalyst

[0012]

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(Wherein, R ¹ , R ² O and R ³
Is as described above, and n is the average number of added moles of the oxyalkylene group, and represents a number of 1 to 100. 5) to 95% by weight of an alkoxypolyalkylene glycol mono (meth) acrylate monomer (a) represented by the formula (4):

[0014]

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(Wherein R ³ is as defined above, and M ¹ represents a hydrogen atom, a monovalent metal atom, a divalent metal atom, an ammonium group or an organic amine group). ) Acrylic acid (salt) monomer (b) 95-
5% by weight, and 0 to 50% by weight of a monomer (c) copolymerizable with these monomers (provided that the total of (a), (b) and (c) is 100% by weight). A cement dispersant containing a polymer (A) derived from the above and / or a polymer salt (B) obtained by further neutralizing the polymer (A) with an alkaline substance.

(3) The alkoxypolyalkylene glycol mono (meth) acrylic acid-based monomer (a) represented by the general formula (3) is

[0017]

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(Wherein, R ³ represents a hydrogen atom or a methyl group; R ⁷ O represents one or a mixture of two or more oxyalkylene groups having 2 to 4 carbon atoms; R ⁸ may be an alkyl group having 1 to 22 carbon atoms, p may be an average number of moles of the oxyalkylene group, and 1 to 97 And a first alkoxy polyalkylene glycol mono (meth) acrylate (a ¹ ) represented by the following general formula (6):

[0019]

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(Wherein, R ³ represents a hydrogen atom or a methyl group, R ⁹ O represents one or a mixture of two or more oxyalkylene groups having 2 to 4 carbon atoms. R ¹⁰ may be an alkyl group having 1 to 22 carbon atoms, q may be an average number of moles of oxyalkylene group added, and may be 4 to 100. Represents an integer of p ≠ q and q−p
≧ 3. The cement dispersant according to the above (2), which is a mixture with the ^second alkoxypolyalkylene glycol mono (meth) acrylate (a ² ) represented by the above (2).

(4) The mixture comprises a mixture of a corresponding alkoxypolyalkylene glycol and a compound of the general formula (2)

[0022]

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(Wherein, R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents an alkyl group having 1 to 22 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms). (3) The cement dispersant according to the above (3), which is obtained by a transesterification reaction with a (meth) acrylate ester.

(5) The first alkoxy polyalkylene glycol mono (meth) acrylate (a ¹ ) and the second alkoxy polyalkylene glycol mono (meth)
The weight ratio of acrylate (a ²⁾ is 5:95 to 95: 5
The cement dispersant according to the above (3), which is:

(6) R ² O is an oxyalkylene group having 2 to 3 carbon atoms, and R ¹ is an oxyalkylene group having 1 to 12 carbon atoms.
The cement dispersant according to the above (2), which is an alkyl group.

(7) The above (6), wherein R ³ is a methyl group.
3. The cement dispersant according to item 1.

(8) The cement dispersant according to the above (2), wherein in the general formula (4), M ¹ is a hydrogen atom or a monovalent metal atom.

(9) Further, at least one cement dispersant selected from the group consisting of a naphthalene cement dispersant, an aminosulfonic acid cement dispersant, a polycarboxylic acid cement dispersant and a lignin cement dispersant. The cement dispersant according to any one of the above (1) to (8), which is blended.

(11) A method for dispersing cement, comprising mixing the cement dispersant according to any one of (1) to (9) above with a cement composition comprising at least cement and water.

(12) The method according to the above (11), wherein the cement dispersant is 0.01 to 1.0% by weight based on the cement, and the weight ratio of water / cement is 0.15 to 0.7. The method for dispersing the cement according to the above.

(13) A cement composition comprising the cement dispersant, cement and water according to any one of (1) to (9).

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION First, a cement dispersant, a method for dispersing cement and a cement dispersant used in a cement composition according to the present invention are alkoxypolyalkylene glycol mono (meth) acrylates obtained by a transesterification method. It is composed of a polymer obtained by polymerizing a monomer component containing a system monomer.

Representative examples of such a cement dispersant include, for example, an alkoxypolyalkylene glycol represented by the general formula (1) and a (meth) acrylate ester represented by the general formula (2): General formula (3) obtained by subjecting to a transesterification reaction in the presence of a basic catalyst
5 to 95% by weight, preferably 50 to 94% by weight, more preferably 60 to 93% by weight of the alkoxypolyalkylene glycol mono (meth) acrylate monomer (a) represented by the general formula (4) The (meth) acrylic acid (salt) monomer (b) shown is 95 to 5% by weight, preferably 50 to 6% by weight, more preferably 40 to 7% by weight and a monomer copolymerizable with these monomers. Monomer (c) 0-5
0% by weight, preferably 0 to 30% by weight, more preferably 0 to 10% by weight (where the total of (a), (b) and (c) is 100% by weight). There is a polymer (A) and / or a polymer salt (B) obtained by further neutralizing the polymer (A) with an alkaline substance.

General formula (1)

[0035]

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In the general formula (1), R ¹ is an alkyl group having 1 to 22 carbon atoms, preferably 1 to 12 carbon atoms, R ² O
Represents one or a mixture of two or more oxyalkylene groups having 2 to 4 carbon atoms, preferably 2 to 3 carbon atoms. In the case of two or more, they may be added in blocks or randomly. M is the average number of moles of the oxyalkylene group added, and 1 to 100, preferably 1 to 5
Represents the number 0.

General formula (2)

[0038]

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In the general formula (2), R ³ represents a hydrogen atom or a methyl group, and R ⁴ has 1 to 2 carbon atoms.
2, preferably 1 to 12 alkyl groups or 3 to 12 carbon atoms, preferably 4 to 8 cycloalkyl groups.

[0040]

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In the general formula (3), R ¹ , R ² O
And R ³ are as described above, and n is the average number of moles of the oxyalkylene group added, and represents a number of 1 to 100, preferably 1 to 50.

Formula (4)

[0043]

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In the general formula (4), R ³ is a hydrogen atom or a methyl group, and M ¹ is a hydrogen atom, a monovalent metal atom, for example, an alkali metal atom such as sodium or potassium, a divalent metal atom, for example. Calcium, magnesium or other alkaline earth metal atoms, ammonium groups or organic amine groups, such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, propylamine, dipropylamine, tripropylamine, isopropylamine, Preferably it is a hydrogen atom or a monovalent metal atom.

An alkoxypolyalkylene glycol,
The transesterification reaction with (meth) acrylic acid ester is
1-20 at a temperature of 40-150 ° C in the presence of a basic catalyst
This is performed for a time, preferably 1 to 10 hours. Further, if necessary, the transesterification reaction can be advanced under reduced pressure.

In general, to obtain an alkoxypolyalkylene glycol mono (meth) acrylate monomer (a), an alkoxypolyalkylene glycol and a (meth) acrylic ester are used in the presence of a basic catalyst as in the present invention. Or a method of esterifying alkoxypolyalkylene glycol and (meth) acrylic acid in the presence of an acid catalyst.

The polymer obtained by polymerizing the monomer component containing the alkoxypolyalkylene glycol mono (meth) acrylate monomer (a) obtained by the transesterification reaction of the present invention has a water reducing performance. It has been found that the present invention is greatly improved, and moreover, surprisingly, the reaction time required to obtain the monomer (a) can be greatly reduced, which is industrially advantageous. It has arrived. It is unknown why the transesterification reaction using a basic catalyst has a better effect on water reduction performance than the esterification reaction using an acid catalyst, but one of the reasons may be that side reactions can be suppressed in the transesterification reaction. Absent. In the esterification reaction using an acid catalyst, (poly) alkylene glycol having hydroxyl groups at both ends is by-produced by ether cleavage of the alkoxypolyalkylene glycol (1), and this is (meth)
An esterification reaction with acrylic acid results in a bifunctional di (meth) acrylate monomer. And this acts as a crosslinking agent in the polymerization reaction of the next step, and gives a high molecular weight crosslinked polymer having poor cement dispersing performance. But,
The cement dispersant of the present invention is not at all limited by such a concept.

In the transesterification reaction between the alkoxypolyalkylene glycol and the (meth) acrylate, the molar ratio of (meth) acrylate / alkoxypolyalkylene glycol is 1/1 to 20/1, particularly 1/1 to 10/1. / 1 is preferred. If it is less than 1/1, the conversion of the transesterification reaction is low, and if it exceeds 20/1, the size of the reaction apparatus and the like is undesirably large.

The basic catalyst used in the transesterification reaction carried out in the present invention includes sodium hydroxide,
Alkali metal hydroxides such as potassium hydroxide and lithium hydroxide; alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide; sodium methoxide, sodium ethoxide, sodium isopropoxide;
Alkali metal alkoxides such as potassium methoxide, potassium ethoxide, and potassium isopropoxide; and strongly basic ion exchange resins having an ammonium salt type amine as an exchange group. Among these basic catalysts, alkali metal hydroxides and metal alkoxides are preferred, and sodium hydroxide or sodium methoxide is particularly preferred. The amount of the basic catalyst to be used is 0.1 to 0.1 with respect to the alkoxypolyalkylene glycol (1).
It is preferably from 01 to 20% by weight, particularly preferably from 0.1 to 10% by weight. If the amount is less than 0.01% by weight, the catalytic effect is not sufficiently exhibited, and if the amount exceeds 20% by weight, it is only uneconomical. The basic catalyst can be charged at once, continuously or dividedly added, but in terms of preventing the catalyst surface from being deactivated in the system and deactivating the catalytic action, continuous or divided addition is performed. Is preferred.

The transesterification can be carried out either batchwise or continuously. For example, in a batch reaction, the internal temperature is gradually increased, and if the alkyl alcohol does not distill even when the temperature reaches the allowable temperature, the termination of the reaction is confirmed. Is done. Then, the raw material (meth) acrylate is distilled off under reduced pressure to obtain the desired alkoxypolyalkylene glycol mono (meth) acrylate monomer (a).

The alkoxypolyalkylene glycol mono (meth) acrylate monomer (a) represented by the general formula (3) obtained by the specific transesterification reaction as described above is represented by the general formula (4) The (meth) acrylic acid (salt) monomer (b) and, if necessary, a monomer (c) copolymerizable with these monomers are subjected to a polymerization reaction.

In order to obtain the copolymer (A), the above monomer components may be copolymerized using a polymerization initiator. The copolymerization can be performed by a method such as polymerization in a solvent or bulk polymerization.

The polymerization in a solvent can be carried out batchwise or continuously, with the solvent used being water;
Lower 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; and the like. Raw material monomer and obtained copolymer (A)
It is preferable to use at least one member selected from the group consisting of water and a lower alcohol having 1 to 4 carbon atoms from the viewpoint of solubility of the compound (A) and convenience in using the copolymer (A).
In this case, among lower alcohols having 1 to 4 carbon atoms, methyl alcohol, ethyl alcohol, isopropyl alcohol and the like are particularly effective.

When the polymerization is carried out in an aqueous medium, a water-soluble polymerization initiator such as ammonium or alkali metal persulfate or hydrogen peroxide is used as the polymerization initiator.
At this time, an accelerator such as sodium bisulfite and Mohr's salt can be used in combination. For polymerization using a lower alcohol, an aromatic hydrocarbon, an aliphatic hydrocarbon, an ester compound or a ketone compound as a solvent, a peroxide such as benzoyl peroxide or lauroyl peroxide; a hydroperoxide such as cumene hydroperoxide; An aromatic azo compound such as bisisobutyronitrile is used as a polymerization initiator. 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.
It is performed within the range of 20 ° 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.

In order to control the molecular weight of the obtained polymer (A), a thiol chain transfer agent can be used in combination. Thiol chain transfer agents used in this case, the general formula HS-R ⁵ -E _g (provided that wherein R ⁵ is 1 to 2 carbon atoms
Represents an alkyl group, E is -OH, -COOM ^2, -
COOR ⁶ or —SO ₃ M ² represents a group, M ² represents hydrogen, a monovalent metal, a divalent metal, an ammonium group or an organic amine group; R ⁶ represents an alkyl group having 1 to 10 carbon atoms; Represents an integer of 1 to 2. And, for example, mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, octyl thioglycolate, and octyl 3-mercaptopropionate. One or more of these can be used.

The polymer (A) thus obtained is
Although it is used as a main component of the cement dispersant as it is, a polymer salt (B) obtained by further neutralizing with an alkaline substance may be used as a main component of the cement dispersant, if necessary. Preferred examples of such an alkaline substance include inorganic substances such as hydroxides, chlorides and carbon salts of monovalent metals and divalent metals; ammonia; and organic amines.

The alkoxypolyalkylene glycol mono (meth) acrylate-based monomer (a) represented by the general formula (3) includes the general formula (5)

[0059]

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(Wherein, R ³ represents a hydrogen atom or a methyl group, R ⁷ O represents one or a mixture of two or more oxyalkylene groups having 2 to 4 carbon atoms. R ⁸ may be an alkyl group having 1 to 22 carbon atoms, preferably 1 to 15 carbon atoms, and p is the average number of moles of oxyalkylene group added. And 1 to 97, preferably 1
Represents an integer of 10 to 10. A) a first alkoxypolyalkylene glycol mono (meth) acrylate (a ¹ ) represented by the general formula (6):

[0061]

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(Wherein, R ³ represents a hydrogen atom or a methyl group, R ⁹ O represents one or a mixture of two or more oxyalkylene groups having 2 to 4 carbon atoms. R ¹⁰ may be an alkyl group having 1 to 22 carbon atoms, preferably 1 to 15 carbon atoms, and q is the average number of moles of oxyalkylene group added. And represents an integer of 4 to 100, preferably 11 to 100, and p q and qp ≧ 3.) And a ^second alkoxypolyalkylene glycol mono (meth) acrylate (a ² ) May be used.

The first alkoxypolyalkylene glycol mono (meth) acrylate (a ¹ ) and the second
To produce a mixture of alkoxy polyalkylene glycol mono (meth) acrylate (a ²⁾ of these first and second alkoxy polyalkylene glycol mono (meth) acrylate (a ¹⁾ and the (a ²⁾ It may be produced separately by a transesterification reaction. Alternatively, it may be produced by a transesterification reaction between a mixture of the corresponding alkoxypolyalkylene glycol and a (meth) acrylic acid ester represented by the general formula (2). In particular, the latter method can provide an industrially inexpensive manufacturing method.

In this case, the first alkoxy polyalkylene glycol mono (meth) acrylate (a ¹ )
Weight ratio with the alkoxypolyalkylene glycol mono (meth) acrylate (a ² ) is 5:95 to 95: 5,
Preferably it is 10:90 to 90:10.

The alkoxypolyalkylene glycol mono (meth) acrylate (a ¹ ) represented by the general formula (5) includes, for example, methoxy (poly) ethylene glycol mono (meth) acrylate, methoxy (poly) propylene glycol mono (meth) acrylate. ) Acrylate,
Methoxy (poly) butylene glycol mono (meth) acrylate, methoxy (poly) ethylene glycol (poly) propylene glycol mono (meth) acrylate,
Methoxy (poly) ethylene glycol (poly) butylene glycol mono (meth) acrylate, methoxy (poly) propylene glycol (poly) butylene glycol mono (meth) acrylate, methoxy (poly) ethylene glycol (poly) propylene glycol (poly) butylene glycol Mono (meth) acrylate, ethoxy (poly) ethylene glycol mono (meth) acrylate, ethoxy (poly) propylene glycol mono (meth) acrylate, ethoxy (poly) butylene glycol mono (meth) acrylate, ethoxy (poly) ethylene glycol (poly) ) Propylene glycol mono (eta) acrylate, ethoxy (poly) ethylene glycol (poly) butylene glycol mono (meth) acrylate, ethoxy (poly) propyl Glycol (poly) butylene glycol mono (meth) acrylate, ethoxy (poly) ethylene glycol (poly) propylene glycol (poly) butylene glycol mono (meth) acrylate and the like. It is important that the alkoxypolyalkylene glycol (meth) acrylate (a) has hydrophobicity in the short-chain alkoxypolyalkylene glycol in the side chain.

From the viewpoint of easy copolymerization, the side chain preferably contains a large amount of ethylene glycol units. Therefore, as the alkoxypolyalkylene glycol mono (meth) acrylate (a ¹ ), an (alkoxy) (poly) ethylene glycol mono (meth) acrylate having an average addition mole number m of 1 to 97, preferably 1 to 10, is preferable.

The long-chain alkoxypolyalkylene glycol mono (meth) acrylate monomer (a ² ) used in the present invention is represented by the above general formula (6), for example, methoxypolyethylene glycol mono (meth) acrylate , Methoxypolyethylene glycol (poly) propylene glycol mono (meth) acrylate, methoxypolyethylene glycol (poly) butylene glycol mono (meth) acrylate, methoxypolyethylene glycol (poly) propylene glycol (poly) butylene glycol mono (meth) acrylate, ethoxypolyethylene Glycol mono (meth) acrylate, ethoxy polyethylene glycol (poly) propylene glycol mono (meth) acrylate, ethoxy polyethylene glycol (poly) butyl Glycol mono (meth) acrylate, ethoxymethyl polyethylene glycol (poly) propylene glycol (poly) butylene glycol mono (meth) acrylate.

In order to obtain a high water-reducing property, an alkoxypolyalkylene glycol mono (meth) acrylate (a
² ) It is important to disperse cement particles due to steric repulsion and hydrophilicity caused by the alkoxypolyalkylene glycol chain having an average addition mole number of 4 to 100 in ² ). For this purpose, it is preferable that a large number of oxyethylene groups be introduced into the polyalkylene glycol chain, and a polyethylene glycol chain is most preferable. The average addition mole number n of the alkylene glycol chain of the alkoxypolyalkylene glycol mono (meth) acrylate (a ² ) is 4 to 100, preferably 1
1 to 100.

The carboxylic acid monomer (b) is represented by the general formula (4). Examples of the monomer (b) include acrylic acid, methacrylic acid, and monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts of these acids. The above can be used.

The monomer (c) is a monomer copolymerizable with the monomers (a) and (b). Examples of the monomer (c) include dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid, and itaconic acid; these dicarboxylic acids and HO (R ¹¹ O) _r R ¹² (where R ¹¹ O Represents one or a mixture of two or more oxyalkylene groups having 2 to 4 carbon atoms, and in the case of two or more, they may be added in block form or in random form, and r is oxyalkylene The average number of moles of the group, from 1 to 100
R ¹² represents hydrogen or an alkyl group having 1 to 22, preferably 1 to 15 carbon atoms. A) monoester or diester with an alcohol represented by the formula:
Unsaturated amides such as (meth) acrylamide and (meth) acrylalkylamide; vinyl esters such as vinyl acetate and vinyl propionate; vinyl sulfonic acid, (meth) allyl sulfonic acid, sulfoethyl (meth) acrylate, and 2-methyl Unsaturated sulfonic acids such as propanesulfonic acid (meth) acrylamide and styrenesulfonic acid and their monovalent metal salts, divalent metal salts, aluminium salts and organic amine salts; aromatic vinyls such as styrene and α-methylstyrene; 1-18 carbon atoms, preferably 1-1
Esters of a phenyl group-containing alcohol such as aliphatic alcohol or benzyl alcohol with (meth) acrylic acid; polyalkylene glycol mono (meth) acrylate; polyalkylene glycol mono (meth) allyl ether; One or more kinds can be used.

The polymer (A) and / or polymer salt (B) used as the cement dispersant of the present invention has a weight average molecular weight of 500 to 500,000, especially 5,000 to 300,000. It is preferable to set the range. If the weight average molecular weight is less than 500, the water dispersing ability of the cement dispersant decreases, which is not preferable. On the other hand, 50
If the molecular weight exceeds 000, the water dispersibility of the cement dispersant and the ability to prevent slump loss are undesirably reduced.

Further, the cement dispersant includes at least one selected from the group consisting of conventionally known naphthalene cement dispersants, aminosulfonic acid cement dispersants, polycarboxylic acid cement dispersants, and lignin cement dispersants. Needless to say, various kinds of cement dispersants may be blended.

In addition to the conventionally known cement dispersants,
Air entrainer, cement wetting agent, swelling agent, waterproofing agent, retarder, quick-setting agent, water-soluble polymer, thickener, flocculant, drying shrinkage reducing agent, strength enhancer, curing accelerator, defoamer Etc. can be blended.

The cement dispersant containing the polymer thus obtained as a main component promotes the dispersion of the cement by being mixed with a cement composition comprising at least cement and water.

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

The cement dispersant used in the present invention exhibits an excellent effect 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, it is used in an amount of 0.01 to 1.0%, preferably 0.02 to 0.
What is necessary is just to add the amount of 5% at the time of kneading.
By this addition, various favorable effects such as achievement of high water reduction rate, improvement of slump loss prevention performance, reduction of unit water amount, increase of strength, and improvement of durability are brought about. If the addition amount is less than 0.01%, the performance is insufficient.
Even if a large amount exceeding% is used, the effect is substantially flattened, and it is disadvantageous from the viewpoint of economy.

The cement composition according to the present invention comprises the above cement dispersant, cement and water. In the cement composition of the present invention, the amount of cement used per 1 m ^{3 of the} cement composition and the unit water amount are not particularly limited, but the unit water amount is 120 to 185 kg / m ³ , and the water / cement weight ratio is 0.15 to 0.15. 0.7, preferably 12 units of water
0-175 kg / m ³ , water / cement weight ratio = 0.2-
0.5% is recommended. The cement composition may further contain aggregates such as sand and gravel if necessary.

[0078]

EXAMPLES The present invention will now be described more specifically with reference to examples. In the examples, unless otherwise specified,%
Represents parts by weight, and parts represents parts by weight.

Example 1 Synthesis of an alkoxypolyalkylene glycol mono (meth) acrylate monomer (a) by transesterification in the presence of a basic catalyst A 300 ml separable flask was charged with a thermometer, a stirrer and a Raschig ring. A packed tower was provided so that the reflux ratio could be changed arbitrarily. In the packed tower, 606 g of methyl methacrylate, 40 methoxypolyethylene glycol (average number of moles of oxyethylene group added: 10 mol) 40
8 g and 0.12 g of phenothiazine as a polymerization inhibitor were charged, and when the temperature at the top of the column reached 50 ° C., 2.65 g of 49% sodium hydroxide was added dropwise over 1 hour and 30 minutes. The methanol-methyl methacrylate azeotrope was distilled off under reduced pressure, and 467 g of the desired methoxypolyethylene glycol monomethacrylate (1) was isolated. The reaction was completed in 3 hours. The yield is 99% or more. The by-produced polyethylene glycol dimethacrylate was 0.1% or less based on the obtained methoxypolyethylene glycol monomethacrylate. Table 1 shows the results.

Example 2 Instead of 408 g of methoxypolyethylene glycol (average number of moles of oxyethylene group: 10 mol), 69 g of methoxypolyethylene glycol (average number of moles of oxyethylene group: 10 mol) and methoxypolyethylene glycol (oxygen group: 10 mol) were used. Average number of moles of ethylene group added: 25
The same operation as in Example 1 was carried out except that 206 g of mol) was used, to obtain a mixture (2) of methoxypolyethylene glycol monomethacrylate. Table 1 shows the results.

Comparative Example 1 Synthesis of alkoxypolyalkylene glycol mono (meth) acrylate monomer (a) by esterification reaction in the presence of an acid catalyst A thermometer, a stirrer and a water separator were placed in a 300 ml separable flask. Provided so that water produced by the reaction can be separated. 805.5 g of methacrylic acid, 1657.8 g of methoxypolyethylene glycol (average number of moles of added oxyethylene groups: 10 mol), 49.3 g of sulfuric acid as an acid catalyst, and 0.1% of phenothiazine as a polymerization inhibitor.
49 g and 73.9 g of cyclohexane as a solvent were charged and heated with stirring. The cyclohexane-water azeotrope was distilled off under normal pressure, and the cyclohexane was refluxed while removing the water of reaction with a separator. The reaction was completed in 25 hours. After the reaction, cyclohexane and excess methacrylic acid were distilled off under normal pressure, and 1858.6 g of methoxypolyethylene glycol monomethacrylate (3) was isolated.
Yield 98%. The by-produced polyethylene glycol dimethacrylate was 12.0% based on the obtained methoxypolyethylene glycol monomethacrylate. Table 1 shows the results.

Comparative Example 2 The same operation as in Comparative Example 1 was carried out except that 218.2 g of paratoluenesulfonic acid was used instead of sulfuric acid as an acid catalyst, to obtain methoxypolyethylene glycol monomethacrylate (4). Table 1 shows the results.

[0083]

[Table 1]

Example 3 Production of Cement Dispersant (1) of the Present Invention 195 g 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 the reactor was stirred. Is replaced with nitrogen, and 95
Heated to ° C. Next, the methoxypolyethylene glycol monomethacrylate (1) obtained in Example 1
4 g, 12.6 g of methacrylic acid, and 15 g of water, and 24 g of a 1.5% ammonium persulfate aqueous solution
For 4 hours, and after completion of the addition, 1.5
6 g of ammonium persulfate was added dropwise over 1 hour. Thereafter, the temperature was maintained at 95 ° C. for 1 hour to complete the polymerization reaction. A cement dispersant (1) of the present invention comprising a polymer having a weight average molecular weight of 36,000 was obtained. Table 2 shows the results
Shown in

Example 4 Preparation of the Cement Dispersant (2) of the Present Invention Instead of the methoxypolyethylene glycol monomethacrylate (1) obtained in Example 1, a mixture of the methoxypolyethylene glycol monomethacrylate obtained in Example 2 A cement dispersant (2) of the present invention was obtained by performing the same operation as in Example 3 except that (2) was used. Table 2 shows the results.

Comparative Examples 3 and 4 Preparation of Comparative Cement Dispersants (1) and (2) Instead of the methoxypolyethylene glycol monomethacrylate (1) obtained in Example 1, Comparative Examples 1 and 2
Example 3 except that the methoxypolyethylene glycol monomethacrylates (3) and (4) obtained in the above were used.
The same operation as described above was performed to obtain comparative cement dispersants (1) and (2). Table 2 shows the results.

[0087]

[Table 2]

Example 5 and Comparative Examples 6 to 7 Concrete Tests Ordinary Portland cement (Chichibu Onoda Cement: specific gravity 3.16) as cement, land sand from Oigawa water system (specific gravity 2.62, FM 2.71) as fine aggregate, Hard sandstone crushed stone from Ome (specific gravity 2.64, MS 20 mm) was used as coarse aggregate. As the cement dispersant, the cement dispersant (1) of the present invention (Example 5) and the comparative cement dispersants (1) and (2) (Comparative Examples 6 and 7) were used. The concrete mixing conditions are a unit cement amount of 320 kg / m ³ , a unit water amount of 165 kg / m ³ and a fine aggregate ratio of 47%.

Under the above conditions, concrete is produced,
All measurements of slump and air volume are based on Japanese Industrial Standards (JIS
A 1101, 1128). Table 3 shows the results.

[0090]

[Table 3]

A comparison of the amount of addition between Example 5 and Comparative Examples 6 and 7 shows that Comparative Examples 6 and 7 are 0.21% and 0.18%, whereas Example 5 has a content of 0.1%. It can be seen that a very low addition amount of 09% is sufficient. Further, comparing the air amounts immediately after the concrete production, the air entrainment was 6.4% in Example 5 while the air amounts in Comparative Examples 6 and 7 were 7.0% and 8.9%, respectively. It can be seen that it can be reduced.

The reason is that the methoxypolyalkylene glycol monomethacrylate (1) produced by the transesterification reaction of Example 1 has a very small crosslinking component of 0.1% or less, while the comparative example 1 It is presumed that the methoxypolyalkylene glycol monomethacrylates (3) and (4) produced by the esterification methods of (1) to (2) have a large amount of crosslinking components of 12.0% and 14.6%, respectively.

By using the monomer obtained by the transesterification reaction, the amount added and the air entrainment can be reduced.

Examples 6-7, Comparative Examples 8-9 Mortar Test Cement dispersants (1) and (2) of the present invention (Example 6)
And 7) and Comparative Cement Dispersants (1) and (2) (Comparative Examples 8 and 9) were added, and the mortar flow value and the air amount were measured. The materials and mortar composition used in the test were 400 g of Chichibu Onoda ordinary Portland cement, 800 g of Toyoura standard sand, and 240 g of water containing the present invention or the comparative cement dispersant.

The mortar was prepared by mechanical kneading using a mortar mixer. The prepared mortar was 55 mm in diameter,
Pack into a 55 mm high hollow cylinder. Next, the cylinder was lifted vertically, and then the diameter of the mortar spread on the table was measured in two directions, and the average was taken as the flow value.
The amount of air was calculated from the weight and volume of the mortar. Table 4 shows the results.

[0096]

[Table 4]

[0097]

According to the present invention, it is possible to provide a cement dispersant, a method for dispersing cement, and a cement composition capable of controlling excessive air entrainment while maintaining excellent water reducing performance.

Further, the cement dispersant according to the present invention is an alkoxypolyalkylene glycol mono (meth) obtained by subjecting an alkoxypolyalkylene glycol and a (meth) acrylate to a transesterification reaction in the presence of a basic catalyst. It is very inexpensive because it is obtained by polymerizing an acrylate monomer and a (meth) acrylic acid (salt) monomer, and if necessary, other copolymerizable monomers.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI // C04B 103: 40 C04B 103: 40 (72) Inventor Shogo Iwai 14-1 Chidoricho, Kawasaki-ku, Kawasaki-shi, Kanagawa Japan Within the catalyst (72) Inventor Koichiro Nagare 14-1 Chidori-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Japan Co., Ltd. (72) Inventor Hideyuki Tahara 992, Koishihama, Nishioki, Abashi-ku, Himeji-shi, Hyogo Japan 56) References JP-A-2-135208 (JP, A) JP-A-4-149050 (JP, A) JP-A-7-247149 (JP, A) JP-A-5-213644 (JP, A) JP 62-78137 (JP, A) JP-A-58-74552 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C04B 22/00-24/42

Claims (15)

(57) [Claims] 1. An alkoxypolyalkylene glycol
And a polymer obtained by polymerizing a monomer component containing an alkoxypolyalkylene glycol mono (meth) acrylate-based monomer obtained by a transesterification reaction with (meth) acrylate. Including cement dispersants. 2. A compound of the general formula (1) (Wherein, R ¹ represents an alkyl group having 1 to 22 carbon atoms, R ² O represents one or a mixture of two or more oxyalkylene groups having 2 to 4 carbon atoms. May be added in the form of a block or may be added in a random manner, and m is the average number of moles of the oxyalkylene group added and represents a number of 1 to 100.) , General formula (2) (Wherein, R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents an alkyl group having 1 to 22 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms). ) Acrylic ester is subjected to a transesterification reaction in the presence of a basic catalyst to obtain a compound represented by the general formula (3): (Wherein, R ¹ , R ² O and R ³ are as described above, and n is an average number of added moles of the oxyalkylene group, and represents a number of 1 to 100). Alkylene glycol mono (meth) acrylate monomer (a) 5 to 95% by weight, general formula (4) (Wherein, R ³ is as described above, and M ¹
Represents a hydrogen atom, a monovalent metal atom, a divalent metal atom, an ammonium group or an organic amine group. 95) to 5% by weight of a (meth) acrylic acid (salt) monomer (b), and a monomer (c) 0 to 5 copolymerizable with these monomers.
0% by weight (provided that the total of (a), (b) and (c) is 100% by weight) and / or the polymer (A) derived from A cement dispersant containing a polymer salt (B) obtained by neutralization with a substance. 3. An alkoxypolyalkylene glycol mono (meth) acrylic acid-based monomer (a) represented by the general formula (3) is a compound represented by the general formula (5): (Where R ³ is a hydrogen atom or a methyl group, R ⁷
O may also be added to one or represents a mixture of two or more thereof, in the case of two or more also be added in a block form randomly shaped oxyalkylene group having 2 to 4 carbon atoms, R ⁸ Is an alkyl group having 1 to 22 carbon atoms, p is an average number of added moles of the oxyalkylene group, and 1
Represents an integer of ~ 97. ) And a first alkoxypolyalkylene glycol mono (meth) acrylate (a ¹ ) represented by the general formula (6): (Wherein, R ³ is a hydrogen atom or a methyl group, R ⁹
O may also be added to one or represents a mixture of two or more thereof, in the case of two or more also be added in a block form randomly shaped oxyalkylene group having 2 to 4 carbon atoms, R ¹⁰ Is an alkyl group having 1 to 22 carbon atoms, q is an average number of added moles of the oxyalkylene group, and 4
Represents an integer of １００100, and p ≠ q and q−p ≧ 3. The cement dispersant according to claim 2, which is a mixture with a ^second alkoxypolyalkylene glycol mono (meth) acrylate (a2) represented by the following formula: 4. The mixture comprises a mixture of a corresponding alkoxypolyalkylene glycol and a compound of the general formula (2) (Wherein, R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents an alkyl group having 1 to 22 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms). 4. The cement dispersant according to claim 3, which is obtained by transesterification with an acrylate ester. 5. The weight ratio of the ^first alkoxypolyalkylene glycol mono (meth) acrylate (a ¹ ) to the second alkoxypolyalkylene glycol mono (meth) acrylate (a ² ) is 5:95 to 95. The cement dispersant according to claim 3, wherein the ratio is: 5. 6. The cement dispersant according to claim 2, wherein R ² O is an oxyalkylene group having 2 to 3 carbon atoms, and R ¹ is an alkyl group having 1 to 12 carbon atoms. 7. The cement dispersant according to claim 6, wherein R ³ is a methyl group. 8. The cement dispersant according to claim 2, wherein in the general formula, M ¹ is a hydrogen atom or a monovalent metal atom. 9. A naphthalene-based cement dispersant,
9. The composition according to claim 1, wherein at least one cement dispersant selected from the group consisting of an aminosulfonic acid cement dispersant, a polycarboxylic acid cement dispersant, and a lignin cement dispersant is blended. 3. The cement dispersant according to item 1. 10. A method for dispersing cement, comprising mixing the cement dispersant according to claim 1 into a cement composition comprising at least cement and water. 11. The cement dispersing agent is 0.01 to 1.0 wt% relative to the cement, also, the weight ratio of water / cement of claim 10 which is 0.15 to 0.7 Cement dispersion method. 12. A cement composition comprising the cement dispersant according to claim 1, a cement and water. 13. The alkoxypolyalkylene glycol mono (meth) acrylate monomer (a) 5.
95% by weight, (meth) acrylic acid (salt) monomer (b) 9
5 to 5% by weight, and 0 to 50% by weight of a monomer (c) copolymerizable with these monomers (the total of (a), (b) and (c) is 100% by weight) ) And / or a polymer salt (B) obtained by further neutralizing the polymer (A) with an alkaline substance.
The cement dispersant according to claim 1, comprising: 14. The alkoxy polyalkylene glycol mono (meth) acrylate monomer (a)
The cement dispersant according to claim 1, which is represented by the following general formula (3). Embedded image (Wherein, R ¹ represents an alkyl group having 1 to 22 carbon atoms, R ² O represents one or a mixture of two or more oxyalkylene groups having 2 to 4 carbon atoms. May be added in block form or in random form, R ³ represents a hydrogen atom or a methyl group, and n is the average number of moles of oxyalkylene group added, Represents.) 15. The method according to claim 1, wherein the alkoxy polyalkylene glycol mono (meth) acrylate monomer is obtained by a transesterification reaction in the presence of a basic catalyst. Cement dispersant.