JPH08100100A - Polymer aqueous solution and cement dispersant - Google Patents

Abstract

PURPOSE: To prepare an aq. polymer soln. which can form a homogeneous and stable aq. soln. and has low foamability and excellent properties as a dispersant for cement. CONSTITUTION: This aq. polymer soln. comprises a water medium, and the following components are incorporated, by the following respective amts. based on the total amount of the aq. soln. into the water medium, that is, (a) 10 to 60wt.% group 2A metal salt of a copolymer of a 4-10C vinyl monomer with an α,β-unsatd. dicarboxylic acid or its anhydride and (b) 0.005 to 0.2wt.% nonionic surfactant having an HLB value of not more than 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous polymer solution having a low foaming property, more specifically, a vinyl monomer and α, β.
-A water-soluble salt of a copolymer with an unsaturated dicarboxylic acid or an anhydride thereof and a nonionic surfactant having an HLB value of 10 or less, low foaming property and good uniformity, a cement dispersant, etc. The present invention relates to an aqueous polymer solution which has excellent performance as a dispersant.

[0002]

2. Description of the Related Art Conventionally, a water-soluble salt of a copolymer of a vinyl monomer having 4 to 10 carbon atoms and an α, β-unsaturated dicarboxylic acid or an anhydride thereof has been used, for example, in paints and coated papers. Widely used in the fields of pigment dispersants, water treatment agents, detergent builders, sizing agents, coal slurry dispersants, cement dispersants (water reducing agents), dye dispersants, agricultural chemical dispersants, metal detergents, adhesives, etc. .

However, the water-soluble salt of the copolymer generally has a foaming property peculiar to the polymer electrolyte. For example, when the aqueous solution is used as a cement dispersant, the cement slurry is foamed. There's a problem. Therefore, when using the aqueous solution, it was necessary to suppress the generation of bubbles by adding an antifoaming agent. However, the method of adding an antifoaming agent has a problem in that the number of working steps is complicated, and in addition, since the amount used is very small, it is difficult to quantitatively add it, and troubles due to excess or deficiency of the addition amount occur. Likely to happen.

Such a problem can be solved if the aqueous solution can previously contain a predetermined amount of an antifoaming agent. However, an anionic surfactant suitable as an antifoaming agent is usually HLB (Hydrophile-Lipop).
It has a small hile balance) value, is hardly soluble in water, and has a further low solubility in an aqueous solution of a high concentration of the water-soluble salt having a solid content concentration of 10% by weight or more, and as a result, is uniform and stable. There is a problem that it is difficult to obtain a proper aqueous solution.

Conventionally, in order to solve such a problem,
(1) 1 to 20 parts by weight of a nonionic surfactant having an HLB value of 12 or more per 100 parts by weight of an alkali metal salt or an ammonium salt of a copolymer of a vinyl monomer having 4 to 10 carbon atoms and an unsaturated dicarboxylic acid anhydride. Homogeneous polyelectrolyte aqueous solution to which is added, and a cement dispersant comprising the aqueous solution (Japanese Patent Publication No. 4-79378, JP-A-5-43287).
No.), (2) mixing a copolymer of a monoolefin and an α, β-unsaturated dicarboxylic acid anhydride with a nonionic surfactant having an HLB value of 6 or less, and then adding an aqueous solution of a base. Have proposed a method for producing a uniform aqueous polymer solution (JP-A-6-166773).

According to these methods (1) and (2), a uniform polymer aqueous solution can be obtained. The aqueous solution is useful as a cement dispersant or the like because it has a low foaming property and an excellent dispersion performance. However, the aqueous polymer solution obtained by these methods is insufficient in performance as a cement dispersant at low temperatures and in the effect when seawater is used as a dispersion medium. Further, these methods are effective only when a monovalent alkali metal salt or ammonium salt is used as a water-soluble salt of the copolymer, and in a divalent or higher polyvalent metal salt, foamability is high. It was said to be large and inferior in stability.

Further, conventionally, (3) a copolymer of an olefin having 4 to 6 carbon atoms and maleic anhydride or a salt thereof and an antifoaming agent (mineral oil type, fat type, fatty acid type, fatty acid ester type, alcohol type, A ready-mixed concrete composition with less slump loss, which is obtained by adding a cement dispersant composed of an amide type, a phosphoric acid ester type, a metal soap type, and a silicone type) to cement together with kneading water, has been proposed (Japanese Patent Application Laid-Open No. 2000-242242). (Sho 61-141652). However, the cement dispersant is intended to prevent the deterioration of the workability of the concrete composition, and the foaming property lowering effect is insufficient.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to contain a water-soluble salt of a copolymer of a vinyl monomer and an α, β-unsaturated dicarboxylic acid or an anhydride thereof and a nonionic surfactant. An object of the present invention is to provide a polymer aqueous solution which is an aqueous solution, forms a uniform and stable aqueous solution, and has a low foaming property and an excellent performance as a dispersant. Another object of the present invention is to provide a cement dispersant containing the aqueous polymer solution as a main component.

The present inventors have found that the vinyl-based monomer and α, which have been known to have a large foaming property and poor stability,
Various studies were conducted on polyvalent metal salts of copolymers with β-unsaturated dicarboxylic acids or their anhydrides. As a result, a Group 2A metal salt of the copolymer and a nonionic surfactant having an HLB value of 10 or less were prepared. By using in combination, a compatible and uniform and stable aqueous solution can be obtained, and the aqueous solution has a performance as a cement dispersant, that is,
It has been found that it has a low foaming property and an excellent dispersion performance.
Low foamability and dispersion performance are excellent even at low temperatures,
Therefore, the cement dispersant comprising the aqueous solution can be suitably used even in the winter and cold regions. Further, since the water-soluble salt of the copolymer is a salt of a Group 2A metal, it has excellent performance as a dispersant even when seawater containing a polyvalent metal ion is used as the aqueous medium.
The present invention has been completed based on these findings.

[0010]

Thus, according to the present invention, (a) a vinyl monomer having 4 to 10 carbon atoms and an α, β-unsaturated dicarboxylic acid or Group 2A metal salt of a copolymer with the anhydride 10
A polymer aqueous solution is provided which contains -60% by weight and (b) 0.005-0.2% by weight of a nonionic surfactant having an HLB value of 10 or less. Further, according to the present invention, there is provided a cement dispersant containing the polymer aqueous solution as a main component.

The present invention will be described in detail below. (A) Component In the present invention, as the polymer electrolyte, (a) a carbon number of 4 to 1
A Group 2A metal salt of a copolymer of a vinyl monomer of 0 and an α, β-unsaturated dicarboxylic acid or an anhydride thereof is used.

(Vinyl monomer having 4 to 10 carbon atoms) In the present invention, the vinyl monomer having 4 to 10 carbon atoms used for producing the copolymer of the component (a) is, for example,
Ethylene, propylene, 1-butene, 2-butene, isobutylene, 1-pentene, 2-pentene, 2-methyl-
1-butene, 2-methyl-2-butene, 4-methyl-1
-Chain monoolefins such as pentene, 1-hexene, diisobutylene, 1-octene; cyclic monoolefins such as cyclopentene and cyclooctene; styrene, α-
Vinyl aromatic compounds such as methylstyrene and vinyltoluene; and other vinyl monomers such as vinyl ether and vinyl acetate.

These vinyl monomers can be used alone or in combination of two or more kinds. Among these vinyl-based monomers, carbon number 4
Chain monoolefins of 6 are preferred.

(Α, β-Unsaturated dicarboxylic acid or its anhydride) In the present invention, the α, β-unsaturated dicarboxylic acid or its anhydride used for producing the copolymer of the component (a) is, for example, Compounds having 4 to 10 carbon atoms such as maleic acid, itaconic acid, citraconic acid, maleic anhydride, itaconic anhydride, and citraconic anhydride. Among these, from the viewpoint of reactivity, quality, economy, etc.,
Maleic anhydride is particularly preferred.

(Copolymer) A copolymer of a vinyl monomer having 4 to 10 carbon atoms and an α, β-unsaturated dicarboxylic acid or an anhydride thereof is usually a vinyl monomer having 4 to 10 carbon atoms. It is a copolymer of 80 mol% and α, β-unsaturated dicarboxylic acid or its anhydride 80 to 20 mol%.
The weight average molecular weight of the copolymer is usually 500 to 10
It is 50,000, preferably 1,000 to 10,000. The weight average molecular weight is a standard polyacrylic acid conversion value measured by a gel permeation chromatography (GPC) method. The method of producing the copolymer is not particularly limited, but a method of copolymerizing in the presence of a radical initiator is preferable. Specific preferred examples of the copolymer include, for example, isobutylene-maleic anhydride, isoamylene-
Examples thereof include maleic anhydride, diisobutylene-maleic anhydride, styrene-maleic anhydride, vinyl acetate-maleic anhydride, vinyl ether-maleic anhydride and the like.

(Group 2A metal) A group 2A metal salt of a copolymer of a vinyl monomer having 4 to 10 carbon atoms and an α, β-unsaturated dicarboxylic acid or an anhydride thereof is used as a base with the copolymer. It can be obtained by reacting with a compound of Group 2A metal of the periodic table. Examples of the 2A group metal compound include basic compounds such as magnesium hydroxide, calcium hydroxide and barium hydroxide. Among these, magnesium hydroxide is preferable from the viewpoints of reactivity, quality, economy and the like.

(Group 2A metal salt) The group 2A metal salt of a copolymer of a vinyl monomer having 4 to 10 carbon atoms and an α, β-unsaturated dicarboxylic acid or an anhydride thereof is an acid in the copolymer. Usually, 0.4 to 1 mol (formula weight), preferably 0.5 to 0. 0, relative to 1 mol of the anhydride group (or dicarboxylic acid).
It can be obtained by reacting 9 mol of the Group 2A metal compound. As a result, the degree of neutralization is 40-100.
%, Preferably 50-90% water-soluble salts are obtained. More specifically, the aqueous solution of the copolymer and the aqueous dispersion or aqueous solution of the basic Group 2A metal compound are heated to a temperature of 100 ° C. or lower by a conventional method and mixed to cause hydrolysis / A salt forming reaction is performed to produce an aqueous solution of a Group 2A metal salt.

0.4 mol or more of the Group 2A metal compound (neutralization degree of 40% or more), preferably 0.5 mol or more, relative to 1 mol of the acid anhydride group (or dicarboxylic acid) in the copolymer. When the reaction is carried out at a ratio of (neutralization degree of 50% or more), alkali metal hydroxide, ammonium or amine is used as the remaining base, and a part of the copolymer is alkali metal salt, ammonium salt or amine salt. Can be

The neutralization reaction of the copolymer with a base is
It can be carried out in the presence of a nonionic surfactant having an HLB value of 10 or less. For example, the powder of the copolymer and a nonionic surfactant are mixed, dissolved in water, and then,
The reaction can be performed by adding an aqueous dispersion or aqueous solution of a basic Group 2A metal compound. Alternatively, in water, the copolymer powder, a nonionic surfactant, and a basic 2
An aqueous dispersion or aqueous solution of a Group A metal compound can be added and mixed together to react. 2A of the above copolymer
It is also possible to modify the remaining acid anhydride group (or dicarboxylic acid) of the group metal salt to introduce an ester group, an amide group, an imide group or the like.

Component (b) Examples of the nonionic surfactant having an HLB value of 10 or less used in the present invention include, for example, polyoxyethylene-polyoxypropylene adduct, ethylenediamine polyoxypropylene-polyoxyethylene adduct, polyoxyethylene-polyoxypropylene adduct. Compounds having a polyoxyalkylene group such as polyhydric alcohol ester polyoxyethylene adduct, polyethylene glycol monoester, polyethylene glycol diester, higher alcohol polyoxyethylene adduct, alkylphenol polyoxyethylene adduct, acetylene glycol polyoxyethylene adduct, etc. Can be mentioned. Among these, acetylene glycol polyoxyethylene adducts are preferable. In addition, the nonionic surfactant HL
The B value is preferably 6 or less from the viewpoint of defoaming property.

Examples of commercially available nonionic surfactants having an HLB value of 10 or less include Surfynol 440.
(HLB = 6, acetylene glycol polyoxyethylene adduct, manufactured by Nisshin Chemical Co., Ltd.), Tetronic 701 (HL
B = 5.2, ethylenediamine polyoxypropylene-
And polyoxyethylene adduct, manufactured by Asahi Denka Co., Ltd., Pluronic L-64 (HLB = 10, polyoxyethylene-polyoxypropylene adduct, manufactured by Asahi Denka Co., Ltd.) and the like. Among these, Surfynol 440 is preferable.

Polymer Aqueous Solution The polymer aqueous solution of the present invention is (a) a vinyl monomer having 4 to 10 carbon atoms and an α, β-unsaturated dicarboxylic acid or an anhydride thereof, based on the total amount of the aqueous solution in an aqueous medium. Group 2A metal salt of a copolymer with 10 to 60% by weight (solid content concentration)
And (b) 0.005 to 0.2% by weight of a nonionic surfactant having an HLB value of 10 or less. The solid content concentration of the 2A group metal salt of the copolymer is preferably 15 to 50% by weight. If the solid content concentration is less than 10% by weight, it is too dilute to be handled, and conversely, if it exceeds 60% by weight, 2% of the copolymer is obtained.
The Group A metal salt is likely to precipitate, and the viscosity of the aqueous solution increases too much, which makes handling difficult.

The nonionic surfactant having an HLB value of 10 or less is 0.005 to 0.2% by weight, preferably 0.01.
˜0.15% by weight. If the proportion of the nonionic surfactant used is too small, the defoaming effect will be small, and conversely, if it is too large, the nonionic surfactant will inherently have a large foaming property, and the nonionic surfactant will precipitate. Easier to do. In order to adjust each component in the aqueous solution to a desired concentration, the proportion of each component used is adjusted and the amount of water used for forming the Group 2A metal salt is adjusted, or in addition to this. Then, when the nonionic surfactant is added, it may be appropriately diluted with water.

The polymer aqueous solution of the present invention has a turbidity at room temperature measured by a turbidimeter of less than 40, preferably less than 35, and more preferably 3 in turbidimetric analysis of the polymer aqueous solution.
It is less than 0, and it is a transparent homogeneous polymer aqueous solution in which a nonionic surfactant is not deposited. When the turbidity of the polymer aqueous solution is 40 or more, the nonionic surfactant is precipitated over time. The polymer aqueous solution of the present invention is a pigment dispersant such as paint or coated paper, a water treatment agent, a detergent builder, a sizing agent, a coal slurry dispersant, a cement dispersant, a dye dispersant, an agricultural chemical dispersant, a metal detergent, It can be used in a wide range of fields as an adhesive or the like. In addition, a general-purpose additive can be added when used for each purpose.

Cement Dispersant The polymer aqueous solution of the present invention is particularly suitable as a cement dispersant because it has a low foaming property and an excellent cement dispersion performance. When the polymer aqueous solution of the present invention is used as a cement dispersant, it is generally 0.01 to 5% by weight, preferably 0.05 to 5% by weight, based on the solid content of the cement.
Used in a proportion of 3% by weight. The cement dispersant of the present invention does not require the addition of a defoaming agent, so that the working process can be simplified. If the proportion of the cement dispersant of the present invention used is too low, the performance as a dispersant is lowered, and conversely, if it is too high, the hardening of cement is adversely affected. The timing of adding the cement dispersant of the present invention to the cement mixture can be appropriately selected according to the purpose of use. As a specific method thereof, for example, a method of premixing with cement, a method of simultaneously adding the cement mixture such as concrete at the time of kneading, a method of adding water or another admixture after starting stirring, and a preliminary mixture After kneading the mixture, a method of adding it at an appropriate interval and adding it later can be mentioned.

The type of cement to which the cement dispersant of the present invention can be applied is not particularly limited. Specific examples thereof include normal Portland cement, early-strength Portland cement, moderate heat Portland cement, alumina cement, fly ash cement, blast furnace cement, silica cement, slag cement, and various mixed cements. It is also effective for the use of cement milk. The cement dispersant of the present invention can be used alone, but may be used in combination with other cement admixtures.
Examples of the cement admixture that can be used in combination include conventional cement dispersants, air entraining agents, cement wetting dispersants, swelling agents, waterproofing agents, strength reinforcing agents, hardening accelerators, freeze accelerators, setting retarders, and the like. .

[0027]

EXAMPLES The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples.

Example 1 Example 1-1 Equimolar copolymer of isoamylene and maleic anhydride obtained by radical polymerization (weight average molecular weight 6000)
100 parts by weight of the powder and 260 parts by weight of an aqueous slurry containing 0.75 equivalent (mol) of magnesium hydroxide were mixed at 80 ° C. with respect to 1 mol of maleic anhydride group in the copolymer, An aqueous Mg salt solution of the copolymer was prepared. Surfynol 440 against 100 parts by weight of the obtained aqueous solution
(Nissin Chemical Co., Ltd. nonionic surfactant; HLB = 6) was added in an amount of 0.05 parts by weight (about 0.05% by weight) to prepare a homogeneous polymer aqueous solution having a solid content of 35% by weight and a turbidity of 27. did.

Example 1-2 Based on 1 mol of the maleic anhydride group in the above copolymer,
A homogeneous polymer aqueous solution having a solid content of 35% by weight and a turbidity of 30 was produced in the same manner as in Example 1-1, except that an aqueous slurry containing 0.9 mol of magnesium hydroxide was used.

Example 1-3 Based on 1 mol of the maleic anhydride group in the above copolymer,
A homogeneous polymer aqueous solution having a solid content of 35% by weight and a turbidity of 23 was produced in the same manner as in Example 1-1, except that a water slurry containing 0.6 mol of magnesium hydroxide was used.

Examples 1-4 With respect to 1 mol of the maleic anhydride group in the above copolymer,
A homogeneous polymer aqueous solution having a solid content of 35% by weight and a turbidity of 21 was produced in the same manner as in Example 1-1, except that an aqueous slurry containing 0.5 equivalent (mol) of magnesium hydroxide was used.

Comparative Example 1 Comparative Example 1-1 A polymer aqueous solution was prepared in the same manner as in Example 1-1 except that sodium hydroxide was used instead of magnesium hydroxide. An aqueous solution with a turbidity of 20% was obtained (neutralization degree 75%).

Comparative Example 1-2 A polymer aqueous solution was prepared in the same manner as in Example 1-1 except that Surfynol 440 was not added, and an aqueous solution having a turbidity of 24 was obtained.

Comparative Example 1-3 A polymer aqueous solution was prepared in the same manner as in Example 1-1 except that the amount of Surfynol 440 added was changed to 0.25% by weight. A homogeneous aqueous solution (mixture) was obtained.

[Example 2] 100 parts by weight of an equimolar copolymer of isoamylene and maleic anhydride (weight average molecular weight 6000) obtained by radical polymerization, and 1 mol of maleic anhydride group in the copolymer. Against 0.75
Water slurry 2 containing an equivalent amount (mol) of magnesium hydroxide
60 parts by weight and 0.2 parts by weight (about 0.05% by weight) of Surfynol 440 (Nonshin Chemical Co., Ltd. nonionic surfactant; HLB = 6) were mixed together at 80 ° C. to obtain a solid content concentration. A 35% by weight aqueous solution of a homogeneous polymer having a turbidity of 27 was produced.

Example 3 100 parts by weight of an equimolar copolymer of isoamylene and maleic anhydride (weight average molecular weight 6000) obtained by radical polymerization, and 1 mol of maleic anhydride group in the copolymer. Against 0.50
Water slurry 2 containing an equivalent amount (mol) of magnesium hydroxide
50 parts by weight were mixed at 80 ° C. to prepare a Mg salt aqueous solution of the copolymer. Furthermore, in this Mg salt aqueous solution, 0.50 was added to 1 mol of the maleic anhydride group in the copolymer.
44 parts by weight of an aqueous solution containing an equivalent amount (1 mol) of sodium hydroxide was added and reacted at 80 ° C. to obtain a uniform aqueous solution.
0.05 parts by weight of Surfynol 440 was added to 100 parts by weight of the obtained aqueous solution to prepare a homogeneous polymer aqueous solution having a solid content of 35% by weight and a turbidity of 25.

Example 4 With respect to each polymer aqueous solution obtained in the above Examples and Comparative Examples, the homogeneity of the aqueous solution and the performance as a cement dispersant were evaluated. Among the performance evaluations as a cement dispersant, the evaluation of foamability is performed at a measurement temperature of 5
Performed at ° C.

(Turbidity) Regarding the homogeneity of an aqueous solution of a polymer, since an aqueous solution having a turbidity of 40 or more is not stable and the nonionic surfactant is separated, it is measured at room temperature (20 ° C.) by a turbidimeter. Turbidity was used as an index.

(Bubble Cell Content) Regarding the foaming property of the aqueous polymer solution, 100 parts by weight of ordinary Portland cement, an aqueous polymer solution in an amount of 0.24 parts by weight in terms of solid content relative to the cement, and the total water content of the cement are A mixture of water having the same weight as that of the mixture was stirred and mixed with a homogenizer to measure the slurry specific gravity, and the bubble content rate (%) was calculated by the ratio with the slurry specific gravity when the aqueous polymer solution was not added. did. The measurement temperature was 5 ° C.

(P funnel depressurizing) 150 parts by weight of clay (kaolin SMA clay having a water content of 85% by weight) was added to 100 parts by weight of the cement slurry in the formulation in the foaming content test, and the mixture was stirred and mixed with a homogenizer to obtain a clay material. Cement dispersibility was evaluated by measuring the flow-down time (seconds) of the mixture by the P-Rot test. The measurement temperature was room temperature (20 ° C.).

[Comparative Example 4] In Example 4, the case where the aqueous polymer solution was not used (blank) was designated as Comparative Example 4. The results are shown in Table 1.

[0042]

[Table 1] (Footnote) SF-440: Surfynol 440

By using a neutralized product of sodium hydroxide of the isoamylene-maleic anhydride copolymer (Comparative Example 1-1), a viscosity reduction of the clay-like composition can be obtained, but the bubble content becomes extremely large. When Surfynol 440 was not added (Comparative Example 1-2), the bubble content rate becomes large. When the use ratio of Surfynol 440 was too large (Comparative Example 1-3), the turbidity increased, and separation of Surfynol 440 was confirmed one day after preparation of the aqueous polymer solution.

On the other hand, in the combined system of the Mg salt of the isoamylene-maleic anhydride copolymer and Surfynol 440 (Examples 1-1 to 1-4), the homogeneity of the aqueous solution and the dispersibility of the cement were good. In addition, the bubble content rate is significantly reduced. When a polymer aqueous solution obtained by allowing Surfynol 440 to be present at the time of neutralization of the isoamylene-maleic anhydride copolymer (at the time of preparing the Mg salt) was used (Example 2), the copolymer was treated with magnesium hydroxide. When an aqueous polymer solution containing a copolymer salt neutralized with both sodium hydroxide and sodium hydroxide is used (Example 3), the bubble content rate is greatly reduced in both cases.

[Example 5] Using the aqueous polymer solution prepared in Example 1-1, calcium carbonate (Sunlight SL-
The viscosity of the 70% by weight water slurry of 700) was measured and the performance as a dispersant was evaluated. Table 2 shows the results.

[0046]

[Table 2] (Footnote) The addition amount indicates the addition rate (% by weight) of the aqueous solution solid content to calcium carbonate. From the results in Table 2, it was confirmed that the polymer aqueous solution of the present invention can be used as a pigment dispersant.

Example 6 Using the aqueous polymer solution prepared in Example 1-1, magnesium hydroxide (UD-65
The viscosity of 40-60 wt% water slurry of 3) was measured and the performance as a dispersant was evaluated. The results are shown in Table 3.

[0048]

[Table 3] (Footnote) The amount added was 0.5% by weight with respect to magnesium hydroxide as the aqueous solution solid content.

The embodiment of the present invention is as follows. (1) Group 2A metal salt 1 of a copolymer of (a) a vinyl monomer having 4 to 10 carbon atoms and an α, β-unsaturated dicarboxylic acid or an anhydride thereof, based on the total amount of the aqueous solution in an aqueous medium.
The polymer aqueous solution containing 5 to 50% by weight and (b) 0.01 to 0.15% by weight of a nonionic surfactant having an HLB value of 10 or less. (2) The aqueous polymer solution according to claim 1, wherein the vinyl-based monomer is a chain monoolefin having 4 to 6 carbon atoms. (3) The polymer, wherein the copolymer is a copolymer of 20 to 80 mol% of a vinyl monomer having 4 to 10 carbon atoms and 80 to 20 mol% of an α, β-unsaturated dicarboxylic acid or an anhydride thereof. Aqueous solution. (4) The polymer aqueous solution, wherein the copolymer is an isoamylene-maleic anhydride copolymer. (5) The polymer aqueous solution, wherein the Group 2A metal is magnesium. (6) The polymer aqueous solution, wherein the nonionic surfactant is an acetylene glycol polyoxyethylene adduct. (7) The polymer aqueous solution, wherein the nonionic surfactant has an HLB value of 6 or less. (8) The cement dispersant, which is used in a proportion of 0.01 to 5% by weight based on the solid content with respect to the cement.

[0050]

According to the present invention, an aqueous solution containing a water-soluble salt of a copolymer of a vinyl monomer and an α, β-unsaturated dicarboxylic acid or an anhydride thereof and a nonionic surfactant is provided. Provided is a polymer aqueous solution which forms a uniform and stable aqueous solution, has a low foaming property and is excellent in the performance as a dispersant. The polymer aqueous solution of the present invention is a cement dispersant,
It can be used in a wide range of fields as a pigment dispersant, a coal-water slurry dispersant, an agricultural chemical dispersant, and the like.

Claims (2)

[Claims] 1. A total amount of the aqueous solution based on the aqueous medium,
(A) 2A of a copolymer of a vinyl monomer having 4 to 10 carbon atoms and an α, β-unsaturated dicarboxylic acid or its anhydride
A polymer aqueous solution containing 10 to 60% by weight of a group metal salt and (b) 0.005 to 0.2% by weight of a nonionic surfactant having an HLB value of 10 or less. 2. A cement dispersant comprising the polymer aqueous solution according to claim 1 as a main component.