JP2000247706A - Cement dispersing agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To impart sufficient fluidity to cement by adding to cement a water soluble polymer having a high molecular monomer unit as an essential structural monomer unit which has a (meth)acrylate having an alkylene oxide chain as an essential structural monomer unit and has a radically polymerizable group on one end of its main chain. SOLUTION: This water soluble dispersing agent having 5,000-15,000 weight average molecular weight is obtained by copolymerizing a polyalkylene glycol mono(meth)acrylate or an alkoxypolyalkylene glycol mono(meth)acrylate each having a 2-3C alkylene oxide chain having 8-50 polymerization degree with a water soluble monomer such as (meth)acrylic acid (or its alkali metal salt) and 2-acrylamide 2-methylpropanesulfonic acid (or its salt). The dispersing agent is added in a content of 0.05-1.5 wt.% in terms of solid content to cement in a cement composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dispersing agent for cement, and more particularly, to an excellent slump flow performance.
Therefore, the present invention relates to a cement dispersant capable of obtaining sufficient fluidity of cement and maintaining the fluidized state.

[0002]

2. Description of the Related Art Cement compounds such as mortar and concrete cause setting when mixed due to the hydration reaction of cement, and lose their fluidity, causing a problem in workability. Therefore, it is required to obtain a fluidity by adding a dispersant and to maintain the fluidity for a certain period of time.

[0003]

For that purpose, a monomer having a nonionic group such as polyalkylene glycol mono (meth) acrylate and an α, β-ethylenically unsaturated carboxylic acid (salt) and / or unsaturated sulfonic acid are used. A cement dispersant comprising a copolymer obtained by copolymerizing (salt) with a water-soluble vinyl monomer is known (JP-B-59-18-18).
338, JP-B5-111057, JP-B-6
-104585). However, with these dispersants, sufficient fluidity cannot be obtained and their maintenance is also insufficient.

[0004] It is an object of the present invention to provide a cement dispersant which is excellent in slump flow performance and therefore can obtain sufficient fluidity of cement and maintain the fluidized state.

[0005]

Means for Solving the Problems The inventors of the present invention have made use of a high molecular weight monomer (generally referred to as a macromonomer, which is also used in the present specification) to obtain a graft chain. The present inventors have found that by using a polymer having a novel structure having the following properties, sufficient fluidity of cement can be obtained and the cement can be maintained.

The dispersant for cement of the present invention comprises, as an essential constituent monomer, an acrylate or methacrylate having an alkylene oxide chain and a high molecular weight monomer comprising a polymer having a radical polymerizable group at one end of the main chain. It is characterized by comprising a water-soluble polymer as a constituent monomer.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. (1) About Macromonomer The macromonomer in the present invention has a skeleton of a polymer (hereinafter sometimes referred to as a basic polymer), and the basic polymer is an acrylate or methacrylate having an alkylene oxide chain (hereinafter, both). Together with a (meth) acrylate) as an essential constituent monomer, and if desired, an unsaturated monomer copolymerizable with the monomer as a constituent monomer. It is a polymer having a radical polymerizable group at one end of the polymer main chain.

Examples of the (meth) acrylate having an alkylene oxide chain include polyalkylene glycol (meth) acrylate and alkoxy polyalkylene glycol mono (meth) acrylate. Polyalkylene glycol mono (meth) acrylate is a compound in which one terminal of a polyalkylene oxide is a hydroxyl group and the other terminal is (meth) acrylated, and more specifically, polyethylene glycol mono (meth) acrylate, and Examples thereof include polypropylene glycol mono (meth) acrylate, and one or more of these can be used in the present invention.

The alkoxypolyalkylene glycol mono (meth) acrylate includes ω-methoxy polyethylene glycol mono (meth) acrylate, ω-ethoxy polyethylene glycol mono (meth) acrylate,
ω-butoxy polypropylene glycol mono (meth) acrylate, ω-benzyloxy polyethylene glycol (meth) acrylate, ω-methoxy polyethylene glycol polypropylene glycol mono (meth) acrylate, ω-methoxy polytetramethylene glycol polyethylene glycol mono (meth) acrylate, etc. Is mentioned. One or more of these can also be used. The alkoxy group is preferably a methoxy group.

In the above (meth) acrylate having an alkylene oxide chain, the degree of polymerization of the alkylene oxide constituting the alkylene oxide chain is preferably from 2 to 100, more preferably from 5 to 80, and particularly preferably from 8 to 50. It is. When the degree of polymerization of the alkylene oxide is 1, sufficient slump flow performance is hardly exhibited, and when the degree of polymerization exceeds 100, the handleability of the obtained basic polymer and macromonomer is reduced. Moreover, the carbon number of the alkylene in these alkylene oxide chains is preferably 2 or 3, and particularly preferably 2.

The unsaturated monomers copolymerizable with the (meth) acrylate having an alkylene oxide chain include unsaturated carboxylic acids, unsaturated dicarboxylic acids, (meth)
Examples include acrylamide, alkyl (meth) acrylate, and aromatic vinyl monomers. More specifically, unsaturated acids such as (meth) acrylic acid, maleic acid, crotonic acid, ascotic acid, citraconic acid, (meth) acrylamide, methyl (meth) acrylate, ethyl (meth) acrylate, and butyl (meth) acrylate (Meth) acrylates such as octyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, stearyl (meth) acrylate, perfluoroalkylethyl (meth) acrylate, perfluoroalkyl (meth) acrylate, and styrene And aromatic monomers such as methylstyrene and α-methylstyrene. These can be used alone or in combination of two or more. Among these, preferred unsaturated monomers are
Alkyl (meth) acrylate, hydroxy (meth) acrylate and acrylamide.

A method for producing a macromonomer is known, and a typical production method is as follows. The first method is to radically copolymerize the above (meth) acrylate having an alkylene oxide chain or an unsaturated monomer copolymerizable with the (meth) acrylate in the presence of a carboxylic acid having a mercapto group. To obtain a basic polymer having a carboxyl group at one end, and an addition reaction of an unsaturated monomer having an epoxy group or an unsaturated monomer having an aziridinyl group with the basic polymer (hereinafter referred to as the carboxyl group method). It is). The second method is to radically polymerize the above monomer in the presence of a carboxylic acid having a mercapto group to obtain a basic polymer having a carboxyl group at one end, and then converting it to an alkali salt. In advance,
This is a method in which an unsaturated monomer having an alkyl halide such as chloromethylstyrene is subjected to an addition reaction (hereinafter, referred to as a desalting method). In the third method, in the presence of a mercapto compound having a hydroxyl group, by radical polymerization of the above monomer, to obtain a basic polymer having a hydroxyl group at one end,
This is a method in which an unsaturated monomer having an isocyanate group or maleic anhydride is subjected to an addition reaction (hereinafter, referred to as a hydroxyl group method).

The basic polymer is usually obtained by radical polymerization in an organic solvent or an aqueous solvent. The polymerization temperature at this time is preferably from 50 to 140 ° C., and the polymerization solvent is preferably ethyl acetate or butyl acetate. , Methyl isobutyl ketone, toluene, isopropyl alcohol (IPA),
Water or xylene is preferred. Examples of the polymerization initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile, azobiscyclohexanecarbonitrile, benzoyl peroxide, toluoyl peroxide, butylperoxypivalate, and butylperoxyoctanoate. The preferred amount thereof is as follows.
0.1 to 3 parts by weight per 00 parts by weight.

Examples of the unsaturated monomer having an epoxy group used in the carboxyl group method include glycidyl acrylate, glycidyl methacrylate, and 3,4-epoxycyclohexylmethyl methacrylate. The amount of the unsaturated monomer having an epoxy group to be used is at least equivalent to the carboxyl group introduced into one terminal of the base polymer, and specifically, 1.0 to 1.
Five-fold moles are preferred. At the time of addition reaction between the carboxyl group and the epoxy group of the base polymer, tertiary amines such as triethylamine and tripropylamine, and quaternary amines such as tetraethylammonium bromide, tetrabutylammonium bromide and triethylbenzylammonium chloride are used to promote the reaction. It is preferable to add an appropriate amount of a quaternary phosphonium salt such as an ammonium salt or a tetrabutylphosphonium salt as a catalyst. The reaction is preferably carried out in an organic solvent inert to the epoxy group, and can be usually carried out in a solution of the basic polymer obtained by solution polymerization in an organic solvent. The reaction temperature is preferably from 50 to 140C.

Examples of the unsaturated monomer having a halogenated alkyl group used in the desalting method include α-chloromethylstyrene. The amount of the unsaturated monomer having a halogenated alkyl group to be used is at least equivalent to the carboxyl group introduced at one end of the basic polymer, and specifically, 1.0 to 1 with respect to the carboxy group. 0.5 moles is preferred. The reaction is preferably performed in a solvent inert to the halogenated alkyl group, and can be generally performed in a solution of a base polymer obtained by solution polymerization. The reaction temperature is preferably from 50 to 140C.

The mercaptocarboxylic acid used in the carboxyl group method and the desalting method includes mercaptoacetic acid, mercaptopropionic acid, mercaptobutyric acid, thiomalic acid and the like. The mercaptocarboxylic acid acts as a chain transfer agent in the polymerization reaction and binds to one end of the base polymer. Therefore, the preferred amount of mercaptocarboxylic acid used is an amount that is equimolar to the obtained base polymer. Specifically, the base polymer: mercaptocarboxylic acid (molar ratio) =
1: (0.8 to 1.3). The number of moles of the obtained basic polymer is determined by the weight of the monomer to be subjected to polymerization and the weight average molecular weight of the polymer. For example, 100 g of monomer
Is used to obtain a basic polymer having a weight average molecular weight of 7,000 (number average molecular weight of 5,000), since the number of moles of the obtained polymer is 0.02, the molecular weight of mercaptocarboxylic acid is 106. If .12 mercaptopropionic acid is used, the amount used is 2.12 g (0.02 g).
Mol) is preferred. The preferred weight average molecular weight of the base polymer is from 1,000 to 30,000. Similarly, examples of the mercapto compound having a hydroxyl group used in the hydroxyl group method include mercaptoethanol, mercaptobutanol, and butanediol monomercaptoacetate, and the required amount is obtained by the same calculation method as described above and used.

In producing the macromonomer, it is possible to use only a (meth) acrylate having an alkylene oxide chain, but it is preferable to use an unsaturated monomer copolymerizable with the (meth) acrylate having an alkylene oxide chain. It is preferable to use
The former is 40 to 90% by weight (more preferably 50 to 90% by weight), and the latter is 10 to 60% by weight (more preferably 10 to 90% by weight).
To 50% by weight).

(2) Water-Soluble Polymer The dispersant for cement of the present invention comprises a water-soluble polymer, and imparts water-solubility to a polymer containing a macromonomer as a constituent monomer to improve cement dispersibility. In order to make the macromonomer excellent, it is also possible to cope with making the macromonomer itself water-soluble, but it is preferable to copolymerize the macromonomer with a water-soluble monomer. It is water-soluble by having a carboxyl group and a salt thereof, a phosphate group, a hydroxyl group, an amino group, and the like,
A compound having a double bond (vinyl group) that can be polymerized with a macromonomer. Specific examples of preferred monomers include unsaturated carboxylic acids or salts thereof, and unsaturated sulfonic acids or salts thereof. More specific examples of the unsaturated carboxylic acid include (meth) acrylic acid, maleic acid, fumaric acid and the like. Among these, (meth) acrylic acid or an alkali metal salt thereof is more preferable, and these can be used alone or in combination of two or more. As the unsaturated sulfonic acid, 2-acrylamide 2
-Methylpropanesulfonic acid, 2-methacrylamide-
2-methylpropylsulfonic acid, styrenesulfonic acid,
Vinyl sulfonic acid, sulfoalkyl acrylate, sulfoalkyl methacrylate, allyl sulfonic acid, methallyl sulfonic acid, 3-methacrylamide-2-hydroxypropyl sulfonic acid, sulfonic acid acrylate, and alkali metal salts thereof. Seed or 2
More than one species can be used. Of these, unsaturated amide sulfonic acids or alkali metal salts thereof are preferable, and 2-acrylamido 2-methylpropane sulfonic acid (salt) is particularly preferable.

When polymerizing the macromonomer, other radically polymerizable monomers can be copolymerized, if necessary. Examples of the monomer include an alkyl (meth) acrylate, an aromatic vinyl monomer, and a (meth) allyl ester. Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, stearyl (meth) acrylate, perfluoroalkyl (Meth) acrylates such as ethyl (meth) acrylate, perfluoroalkyl (meth) acrylate, hydroxyalkyl (meth) acrylate, and alkylene glycol (meth) acrylate; and aromatic monomers such as styrene, methylstyrene, and α-methylstyrene And vinyl acetate. One or more of these can be used.

(3) Polymerization Method and Polymer The polymerization method is preferably radical polymerization in an organic solvent or water, and the polymerization temperature is preferably 50 to 140 ° C., and the polymerization solvent is ethyl acetate or butyl acetate. , Methyl isobutyl ketone, toluene or xylene, isopropyl alcohol, water and the like can be preferably used. Examples of the polymerization initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile, azobiscyclohexanecarbonitrile, benzoyl peroxide, toluoyl peroxide, butyl peroxypivalate, persulfate, and butyl peroxyoctanoate. And the preferred amount thereof is 0.1 to 7 per 100 parts by weight of the monomer.
Parts by weight (hereinafter abbreviated as "part").

In the polymer of the present invention, a macromonomer, a water-soluble monomer and another radical polymerizable monomer are
Macromonomer 30 to 98% by weight (more preferably 60 to 95% by weight), water-soluble polymer 2 to 60% by weight (more preferably 5 to 40% by weight),
It is preferable to use the other radical polymerizable monomer so as to be 0 to 30% by weight (more preferably 0 to 15% by weight). If the polymerization ratio of the macromonomer is out of this range,
The change with time of the slump flow tends to increase. On the other hand, when the polymerization ratio of the water-soluble monomer is out of this range, the dispersibility tends to deteriorate, and the slump flow tends to decrease.
Further, when the polymerization ratio of the other radically polymerizable monomer is out of this range, the effect of the present invention is hardly exhibited.

The weight average molecular weight of the polymer in the present invention is preferably from 1,000 to 500,000, more preferably from 4,000 to 30,000, and still more preferably from 5,000 to 15,000. When the weight average molecular weight is less than 1,000, it is difficult to obtain a dispersing effect on cement. On the other hand, the weight average molecular weight is 500,000
If it exceeds, the viscosity of the polymer becomes too high, so that the handleability at the time of production and at the time of use deteriorates, which is not preferable. The weight average molecular weight is a molecular weight in terms of polyethylene oxide determined by aqueous gel permeation chromatography. In addition, the cement mortar containing the cement dispersant comprising the polymer according to the present invention has a slump flow value of 15 or more, preferably 16 or more, more preferably 18 or more immediately after measured by the test method performed in the following examples. As described above, it can be usually 25 or less. Slump flow value after 2 hours is 10 or more, preferably 12 or more, more preferably 14 or more, especially 15 or more.
As described above, the number can be usually set to 20 or less. The difference between the two is 4 or less, preferably 3 or less, and more preferably 2.
5 or less.

(4) Method of Using Dispersant for Cement The dispersant for cement of the present invention is added to a cement composition using hydraulic cement such as various Portland cements, fly ash cements, various mixed cements and special cements. Used as This dispersant is preferably added to the cement composition as an aqueous solution, but may be added as a powder or a granule, or may be added after kneading the cement composition. Also,
When it is added in the form of powder or granules, it can be kneaded after being premixed with cement or a cement compound component such as aggregate in advance.

The amount of the dispersant for cement of the present invention is preferably 0.005 to 2.5% by weight in terms of solid content based on the cement in the cement composition.
More preferably, the content is set to 0.05 to 1.5% by weight. If the amount is less than the above range, the slump flow performance may be insufficient. On the other hand, if it is added beyond the above range, the effect tends to saturate, so that it is not economical, and there is a possibility that problems such as retardation of coagulation and excess air entrainment may occur. The present dispersant for cement may be used alone, or may be used in combination with a conventionally known dispersant for cement such as a water reducing agent or a fluidizing agent.

(5) Action The dispersant for cement of the present invention is obtained by copolymerizing a macromonomer having an alkylene oxide chain as a side chain, preferably a water-soluble monomer such as an unsaturated carboxylic acid. Polymer is used. The structure of the polymer is a double graft structure in which the graft chain further has a graft chain, and a nonionic portion of an alkylene oxide chain is formed in the graft portion. Further, a polar part such as an anion is formed in the main chain. Therefore,
Since the dispersant for cement of the present invention has a very large area occupied by the nonionic portion of the alkylene oxide chain, it is considered that the dispersant greatly impedes the penetration of water into the cement particles. Therefore, the dispersant for cement of the present invention exhibits extremely excellent slump flow performance, obtains sufficient fluidity of cement, and enables maintenance thereof.

[0026]

The present invention will be described more specifically with reference to Test Examples 1 to 9, Examples 1 to 14 and Comparative Examples 1 to 6. [Test Examples 1 to 9] This test example relates to the production of various macromonomers. (Test Example 1) A mixture of 100 parts of toluene and 1.8 parts of 3-mercaptopropionic acid was heated to 90 ° C under a nitrogen stream and stirred, and ω-methoxypolyethylene glycol monomethacrylate (ethylene oxide Average polymerization degree 9) 60 parts, ethyl acrylate (EA) 40
And 1 part of azobisisobutyronitrile were added dropwise over 4 hours. By further heating for 2 hours, a toluene solution of a basic polymer having a carboxyl group at one end was obtained (see Table 1). 2.65 parts of glycidyl methacrylate, 0.9 parts of tetrabutylammonium bromide, 0.0 parts of hydroquinone monomethyl ether were added to the obtained solution.
A solution obtained by diluting 5 parts with 10 parts of toluene was added dropwise, and the mixture was heated at 110 ° C. for 3 hours under an air bubble. Thereafter, the solvent was removed with a spray dryer to obtain 98 parts of a solid macromonomer. Its weight average molecular weight was 6,000 (see Table 1). The weight average molecular weight (MW) is
It is a molecular weight in terms of polyethylene oxide determined by aqueous gel permeation chromatography.

Test Example 2 In this test example, ω-methoxy polyethylene glycol monomethacrylate 80 was used.
Parts, and 20 parts of ethyl acrylate (EA) in the same manner as in Test Example 1, except that the macromonomer (MW;
3,000) (see Table 1).

Test Example 3 A mixture of 100 parts of water and 1.8 parts of 3-mercaptopropionic acid was heated at 95 ° C. under a nitrogen stream.
Under stirring and stirring, 80 parts of ω-methoxypolyethylene glycol monomethacrylate (average degree of polymerization of ethylene oxide: 23), 20 parts of hydroxyethyl acrylate (HEA), and 0.9 parts of azobisisobutyronitrile Was added dropwise over 4 hours. By further heating for 2 hours, an aqueous solution of a polymer having a carboxyl group at one end was obtained (see Table 1). To the resulting solution, 2.65 parts of chloromethylstyrene, 0.9 parts of tetrabutylammonium bromide and 0.05 parts of hydroquinone monomethyl ether were added dropwise, and the mixture was heated to 110 ° C. under an air bubble.
For 3 hours to obtain a macromonomer. The weight average molecular weight of the obtained macromonomer was 10,000 (see Table 1).

(Test Examples 4 to 9) In each of the test examples, each of the monomers shown in Table 1 was blended at a predetermined weight ratio, and a macromonomer was obtained in the same manner as in Test Example 3. The weight average molecular weight of each macromonomer was measured, and the results are shown in Table 1.
In addition, "AMD" shown in Table 1 represents acrylamide.

[0030]

[Table 1]

[Examples 1 to 14] This example relates to preparation of a dispersant for cement and evaluation of its performance.

(Example 1) 100 parts of IPA and Test Example 1
A mixture of 83 parts of the macromonomer at 90 ° C. under a nitrogen stream
And 17 parts of acrylic acid (AA) and 2 parts of azobisisobutyronitrile were added dropwise over 4 hours while stirring.
After further heating for 1 hour, IPA was removed under reduced pressure, replaced with water, adjusted to pH 8.0 with sodium hydroxide, and polymer (M
W; 7,000) was obtained (see Table 2).

(Examples 2 to 4) In the present examples, the respective polymers shown in Table 2 were blended at a predetermined weight ratio, and each polymer was produced in the same manner as in Example 1. The weight average molecular weights of these polymers were measured, and the results are shown in Table 2. Table 2
"MAA" in the above indicates methacrylic acid, and "ATBS" (manufactured by Toagosei Co., Ltd.) indicates 2-acrylamide 2-methylpropanesulfonic acid. “ATBS” is a registered trademark of Toagosei Co., Ltd.

Example 5 A mixture of 60 parts of water, 40 parts of IPA and 76 parts of the macromonomer of Test Example 3 was heated to 90 ° C. under a nitrogen stream, and 24 parts of acrylic acid (AA) and azobis 2 parts of isobutyronitrile was added dropwise over 4 hours. After heating for another hour, IPA was removed under reduced pressure,
The polymer (MW; 1) was adjusted to pH 8.0 with sodium hydroxide.
2,000).

(Embodiments 6 to 14)
Were mixed at a predetermined weight ratio, and each polymer was produced in the same manner as in Example 5. The weight average molecular weights of these polymers were measured, and the results are shown in Table 2.

[0036]

[Table 2]

Comparative Examples 1 to 6 (Comparative Example 1) A mixture of 60 parts of water, 60 parts of IPA and 62 parts of methoxypolyethylene glycol monomethacrylate (average degree of polymerization of ethylene oxide: 9) was heated to 90 ° C. under a nitrogen stream. Under stirring, 38 parts of acrylic acid (AA) and 2 parts of azobisisobutyronitrile were added dropwise over 4 hours. After further heating for 1 hour, IPA was removed under reduced pressure, and the pH was adjusted to 8.0 with sodium hydroxide to obtain a polymer. The weight average molecular weight was measured, and the results are shown in Table 3.

(Comparative Examples 2 to 6) In this comparative example, each of the monomers shown in Table 3 was blended at a predetermined ratio and polymerized in the same manner as in Comparative Example 1 to obtain a polymer. These weight average molecular weights were measured, and the results are shown in Table 3.

[0039]

[Table 3]

[Evaluation of Performance] The mortar flow performance of the polymer dispersant prepared in each of Examples 1 to 14 and Comparative Examples 1 to 6 was measured by the following method. Cement mortars were prepared using the above aqueous dispersant solutions at the following compounding ratios. In addition, ordinary Portland cement manufactured by Sumitomo Osaka Cement was used as "cement", and Toyoura standard sand for cement test was used as "sand". The water / cement ratio of this cement mortar is 0.5
It is. As a specific operation method, cement and sand are first pre-mixed, transferred to a cup and stirred,
Each aqueous dispersant solution diluted with water was added. Immediately after the completion of the addition and two hours after the completion of the addition, JIS R5201
The slump flow value was measured according to the flow test. The results are shown in Tables 2 and 3. In addition, immediately after the completion of the addition and 2
The difference between the flow values after the time is also shown in Table 2. [Blending ratio (solid content ratio)]; Cement: 100 parts, sand: 200 parts, water: 50 parts, dispersant: 0.2 part

[Effects of Examples and Comparative Examples] Comparative Examples 1 to 6
All dispersants have a nonionic group portion of an alkylene oxide chain and an anionic group called a carboxyl group, but a simple copolymer of two or three monomers is a component. It was 14 or less, and the slump flow after 2 hours could not be measured because a good slurry was not formed. In particular, Comparative Examples 1-4
Then, the immediately following slump flow value was even smaller at 12 or less. On the other hand, the dispersants of Examples 1 to 14 show a double-branched structure because the component is a polymer using a macromonomer. In the dispersants of Examples 1 to 14,
Immediately after, the slump flow value showed a large value of 15.5 to 19.7. In addition, the slump flow value after 2 hours also shows an extremely large value of 13.1 to 17.6, and the difference between the two values is extremely small at 0.7 to 3.2. In particular, in Examples 1-2, 5-9, and 11-14, the difference was extremely small at 2.0 or less, indicating that there was little change over time. From the above, it can be seen that the dispersants of Examples 1 to 14 are excellent in fluidity and extremely excellent in maintaining the fluid state. In particular, in Examples 8 to 12 using macromonomers (Test Examples 6 to 8, especially Test Examples 7 to 8) having a large number of moles of ethylene oxide added, the immediate slump flow value was 18.7 to 19. 7,2
After the time, the slump flow value shows an extremely large value of 17.5 to 17.9. In the present invention, the dispersant having excellent dispersing performance can be obtained by changing various conditions within the scope of the present invention according to the purpose and application without being limited to those shown in the specific examples.

[0042]

The cement dispersant of the present invention is very useful because it has a very good slump flow performance and can obtain sufficient fluidity of the cement and can maintain the fluidized state.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shiro Kojima 1 at Funamicho, Minato-ku, Nagoya City Toagosei Co., Ltd. Nagoya Research Institute, Inc. (72) Inventor Ken Takeda 1 at Funamicho 1, Minato-ku, Nagoya City Synthetic Nagoya Research Institute Co., Ltd. (72) Inventor Minoru Atsuchi 1 at Funamicho, Minato-ku, Nagoya 1 Toagosei Nagoya Research Institute Co., Ltd.

Claims (3)

[Claims] 1. An aqueous solution containing an acrylate or methacrylate having an alkylene oxide chain as an essential constituent monomer and a high molecular weight monomer comprising a polymer having a radical polymerizable group at one end of a main chain as an essential constituent monomer. A dispersant for cement, comprising a water-soluble polymer. 2. The cement dispersant according to claim 1, wherein the water-soluble polymer contains a water-soluble monomer as an essential constituent monomer. 3. The cement dispersant according to claim 2, wherein the water-soluble monomer is α, β-ethylenically unsaturated carboxylic acid or unsaturated sulfonic acid or an alkali salt thereof.