KR102192163B1 - Dispersion retention agent for hydraulic compositions - Google Patents

Abstract

It is possible to maintain the fluidity of the hydraulic composition even after a long time elapsed from kneading, and further provides a dispersion-retaining agent for hydraulic compositions without delaying curing. As a dispersion-retaining agent for hydraulic compositions, a vinyl copolymer in which a specific monomer having a carboxylic acid in a molecule, a specific monomer having a polyalkylene glycol residue in the molecule, and, if necessary, another monomer copolymerizable with these monomers, is prepared. Used.

Description

Dispersion retention agent for hydraulic compositions

The present invention relates to a dispersion retaining agent for a hydraulic composition. Various dispersants are widely used in the manufacture of hydraulic compositions such as mortar and concrete. However, in general, when a hydraulic composition is prepared using a dispersant, a slump loss (deterioration of fluidity over time) is large, and workability and workability are deteriorated. The present invention relates to a dispersion-retaining agent for a hydraulic composition capable of sufficiently preventing slump loss.

Conventionally, dispersants for hydraulic compositions made of water-soluble vinyl copolymers have been proposed as having their own slump loss prevention performance (see, for example, Patent Documents 1 to 4). However, in these conventional proposals, there is a problem that the slump loss of the produced hydraulic composition cannot be sufficiently prevented. Accordingly, it has also been proposed that a slump loss prevention agent is used in combination with a dispersant for a hydraulic composition (see, for example, Patent Document 5). However, even in such a conventional proposal, there is a problem that the slump loss of the manufactured hydraulic composition still cannot be sufficiently prevented.

Patent Document 1: Japanese Patent Laid-Open Publication No. 63-285140 Patent Document 2: Japanese Laid-Open Patent Publication No. H1-226757 Patent Document 3: Japanese Laid-Open Patent Publication No. Hei 10-67549 Patent Document 4: Japanese Laid-Open Patent No. 2003-335562 Patent Document 5: Japanese Laid-Open Patent No. 2003-34565

The problem to be solved by the present invention is to provide a dispersion-retaining agent for a hydraulic composition that can maintain the fluidity of a hydraulic composition even after a long period of time elapses from kneading, and has little delay in curing.

Accordingly, the present inventors have studied to solve the above problems, as a result of researching a specific monomer having a carboxylic acid group in the molecule, a specific monomer having a polyalkylene glycol residue in the molecule, and, if necessary, other monomers copolymerizable with these monomers. It has been found that the vinyl copolymer obtained by copolymerization is certainly suitable as a dispersion-retaining agent for hydraulic compositions.

That is, the present invention relates to a dispersion retaining agent for a hydraulic composition comprising a vinyl copolymer obtained from a monomer A represented by the following formula (1) and a monomer B represented by the following formula (2). In addition, the present invention contains a vinyl copolymer obtained from a monomer A represented by the following formula (1), a monomer B represented by the following formula (2), and another monomer C copolymerizable with these monomers. It is about my.

[Formula 1]

[Formula 2]

In Formula 1 and Formula 2,

R ¹ , R ² : hydrogen atom, methyl group, or organic group represented by the following formula (3)

p: 0 or 1

X: an organic group represented by the following formula (4)

Y: an organic group represented by the following formula (5)

M ¹ : hydrogen atom, ammonium group, organic amine group, alkali metal or 1/2 equivalent of alkaline earth metal

[Formula 3]

In Formula 3,

r: 0 or 1

M ² : hydrogen atom, ammonium group, organic amine group, alkali metal or 1/2 equivalent of alkaline earth metal

[Formula 4]

In Formula 4,

AO: C2-C4 oxyalkylene group

m: an integer from 1 to 10

R3: Alkylene group, aromatic ring group or unsaturated hydrocarbon group which may have a hetero atom

[Formula 5]

In Formula 5,

s: an integer from 0 to 4

t: 0 or 1

AO: C2-C4 oxyalkylene group

n: an integer from 0 to 300

R ⁴ : A hydrogen atom, an alkyl group having 1 to 22 carbon atoms, or an aliphatic acyl group having 1 to 22 carbon atoms (however, when n=0, R ⁴ is an alkyl group having 1 to 22 carbon atoms or an aliphatic acyl group having 1 to 22 carbon atoms)

In the dispersion-retaining agent for hydraulic compositions according to the present invention (hereinafter referred to as the dispersion-retaining agent of the present invention), a vinyl copolymer obtained from monomer A represented by Formula 1 and monomer B represented by Formula 2 (hereinafter, vinyl Also included are those containing a copolymer P) and a vinyl copolymer (hereinafter referred to as vinyl copolymer Q) obtained from such a monomer A, such a monomer B, and another monomer C copolymerizable therewith.

First, the vinyl copolymer P is demonstrated. The vinyl copolymer P is a vinyl copolymer obtained from monomer A and monomer B, and the ratio of both is not particularly limited, but 1 to 99 mol% of the constituent units derived from the monomer A and the monomer B derived A vinyl copolymer having a mass average molecular weight of 8000 to 200000 having a structural unit in a ratio of 1 to 99 mol% (total 100 mol%) is preferred.

In Formula 1 representing monomer A, R ¹ is a hydrogen atom, a methyl group, or an organic group represented by Formula 3, p is 0 or 1, X is an organic group represented by Formula 4, and M ¹ is a hydrogen atom. , Ammonium group, organic amine group, alkali metal or 1/2 equivalent of alkaline earth metal. In Formula 3, r is 0 or 1, M ² is a hydrogen atom, an ammonium group, an organic amine group, an alkali metal or 1/2 equivalent of an alkaline earth metal, but the organic group represented by Formula 3 is specifically a carboxyl group or a methylene carboxyl group. .

Further, in the general formula (4), AO is an oxyalkylene group having 2 to 4 carbon atoms, m is an integer of 1 to 10, and R ³ is an alkylene group, an aromatic cyclic group, or an unsaturated hydrocarbon which may have a hetero atom.

In the general formula (4), examples of the oxyalkylene group of AO include an oxyethylene group, an oxypropylene group, and an oxybutylene group, but an oxyethylene group and an oxypropylene group are preferable, and an oxyethylene group is more preferable. These may be one type or two or more types. m is an integer of 1 to 10, preferably an integer of 1 to 5, and more preferably 1 or 2. R ³ is an alkylene group, an aromatic ring group or an unsaturated hydrocarbon group which may have a hetero atom, and the number of carbon atoms thereof is not particularly limited. Examples of the alkylene group which may have a hetero atom include a methylene group, an ethylene group, a propylene group, a butylene group, a cyclohexyl group, an oxymethylene group, an oxyethylene group, an oxypropylene group, and an oxybutylene group. In addition, aromatic ring groups that may have a hetero atom include phenylene group, tolylene group, naphthylene group, thiophene, furan, pyrrole, benzothiophene, benzofuran, benzopyrrole, triazine, imidazole, benzoimidazole, Triazole, thiadiazole, thiazole, etc. are mentioned. In addition, examples of the unsaturated hydrocarbon group which may have a hetero atom include an ethynyl group, a propynyl group, a butynyl group, and a group having a carbonyl group or an imino group before and after these, but an organic group represented by the following formula (6) is preferable.

[Formula 6]

In Formula 6, R ⁵ is an alkylene group having 1 to 22 carbon atoms, an aromatic cyclic group or an unsaturated hydrocarbon group, which may have a hetero atom, u is an integer of 0 to 2, M ³ is a hydrogen atom, organic ammonium group, oil It is an instrument, an alkali metal or 1/2 equivalent of an alkaline earth metal.

In Formula 6, R ⁵ is an alkylene group having 1 to 22 carbon atoms, an aromatic ring group or an unsaturated hydrocarbon group, which may have a hetero atom, and an alkylene group, an aromatic ring group or an unsaturated hydrocarbon group that may have a hetero atom. The group is as described above for R ³ in Formula 4, but R ⁵ is one having 1 to 22 carbon atoms, and preferably one having 1 to 6 carbon atoms.

In Formula 1, Formula 3, and Formula 6, M ¹ , M ² , M ³ are hydrogen atoms, ammonium groups, organic amine groups, alkali metals, or 1/2 equivalent of alkaline earth metal. These may be one type or two or more types. Examples of the ammonium group include an ammonium group, a tetramethylammonium group, and a tetrabutylammonium group. In addition, examples of the organic amine group include alkylamine groups such as methylamine group, dimethylamine group, trimethylamine group, and triethylamine group, alkanolamine groups such as diethanolamine group and triethanolamine group, pyridinium group, and rutidinium ( and aromatic amine groups such as lutidinium) group. Moreover, lithium, sodium, potassium, cesium, etc. are mentioned as an alkali metal. And examples of the alkaline earth metal include calcium, magnesium, and barium. However, in the case of alkaline earth metal, it is 1/2 equivalent.

Specific examples of the monomer A described above include 2-acryloyloxyethyl succinic acid, 2-methacryloyloxyethyl succinic acid, 2-acryloyloxyethyl hexahydrophthalate, 2-acryloyloxyethyl phthalate, and the like. In addition, a condensation product of an unsaturated carboxylic acid ester having a hydroxyl group at the terminal such as hydroxyethyl (meth) acrylate, polyoxyethylene mono (meth) acrylate, and 2 to 4 basic carboxylic anhydrides Can be lifted. Such a condensation product is obtained by condensation of an unsaturated carboxylic acid ester having a hydroxyl group at the terminal and a 2 to 4 basic carboxylic anhydride. Unsaturated carboxylic acid esters that can be used for condensation include hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, and hydroxybutyl methacrylate. Rate, polyoxyalkylene mono (meth)acrylic acid ester, and the like. In addition, examples of 2 to 4 basic carboxylic anhydrides that can be used for condensation include succinic anhydride, maleic anhydride, trimellitic anhydride, cyclohexyl 1, 2 dicarboxylic anhydride, pyromellitic anhydride, and the like. . As the monomer A, one or two or more of these condensates may be used, but a condensation product of hydroxyethyl (meth)acrylate and 2 to 4 basic carboxylic anhydrides is preferable.

The condensate can be obtained by a known method. This includes, for example, a method of heating and stirring an unsaturated carboxylic acid ester having a hydroxyl group at the terminal and a 2 to 4 basic carboxylic anhydride in no solvent, and an unsaturated carboxylic acid ester having a hydroxyl group at the terminal in the presence of a solvent and a condensing agent. And a method of condensing with 2 to 4 basic carboxylic anhydrides.

In Formula 2 representing monomer B, R ² is a hydrogen atom, a methyl group, or an organic group represented by Formula 3, and Y is an organic group represented by Formula 5. In Formula 5, s is an integer of 0 to 4, t is 0 or 1, AO is an oxyalkylene group having 2 to 4 carbon atoms, n is an integer of 0 to 300, R ⁴ is a hydrogen atom, an alkyl group having 1 to 22 carbon atoms Or an aliphatic acyl group having 1 to 22 carbon atoms. However, when n=0, R ⁴ is an alkyl group having 1 to 22 carbon atoms or an aliphatic acyl group having 1 to 22 carbon atoms.

Examples of R ⁴ in the formula (5) include 1) hydrogen atom, 2) methyl group, ethyl group, butyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tetradecyl group, pentadecyl group, Hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group, heneicosyl group, docosyl group, tricosyl group, tetracosyl group, pentacosyl group, hexacosyl group, heptacosyl group, octacosyl group, 2 -Methyl-pentyl group, 2-ethyl-hexyl group, 2-propyl-heptyl group, 2-butyl-octyl group, 2-pentyl-nonyl group, 2-hexyl-decyl group, 2-heptyl-undecyl group, 2- An alkyl group having 1 to 22 carbon atoms such as an octyl-dodecyl group, 2-nonyl-tridecyl group, 2-decyl-tetradecyl group, 2-undecyl-pentadecyl group, and 2-dodecyl-hexadecyl group, 3) for Wheat group, acetyl group, propanoyl group, butanoyl group, hexanoyl group, heptanoyl group, octanoyl group, nonanoyl group, decanoyl group, hexadecanoyl group, octadecanoyl group, hexadecenoyl group, eicosenoyl group, octade C1-C22 aliphatic acyl groups, such as a cenoyl group, are mentioned. Among these, as R ⁴ , a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and an aliphatic acyl group having 1 to 4 carbon atoms are preferable.

AO in Formula 5 is the same as described above for AO in Formula 4, and n is an integer of 0 to 300, but (AO)n is composed of 0 to 160 oxyethylene units and/or oxypropylene units ( A poly)oxyalkylene group is preferred.

Specific examples of the monomer B described above include hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, methyl acrylate methyl methacrylate, propyl acrylate, propyl methacrylate. , Butyl acrylate, butyl methacrylate, α-aryl-ω-acetyl-(poly)oxyethylene, α-aryl-ω-acetyl-(poly)oxyethylene (poly)oxypropylene, α-aryl-ω-hydroxy -(Poly)oxyethylene, α-aryl-ω-hydroxy-(poly)oxyethylene (poly)oxypropylene, α-metaryl-ω-hydroxy-(poly)oxyethylene, α-metharyl-ω- Methoxy-(poly)oxyethylene, α-metaryl-ω-hydroxy-(poly)oxyethylene (poly)oxypropylene, -metaryl-ω-acetyl-(poly)oxyethylene, α-(3-methyl) -3-butenyl)-ω-hydroxy-(poly)oxyethylene, α-(3-methyl-3-butenyl)-ω-butoxy-(poly)oxyethylene, α-(3-methyl-3 -Butenyl)-ω-hydroxy-(poly)oxyethylene (poly)oxypropylene, α-(3-methyl-3-butenyl)-ω-acetyl-(poly)oxyethylene (poly)oxypropylene, α -Acryloyl-ω-hydroxy-(poly)oxyethylene, α-acryloyl-ω-methoxy-(poly)oxyethylene, α-acryloyl-ω-butoxy-(poly)oxyethylene, α-acryloyl-ω-methoxy-(poly)oxyethylene (poly)oxypropylene, α-methacryloyl-ω-hydroxy-(poly)oxyethylene, α-methacryloyl-ω-meth Oxy-(poly)oxyethylene, α-methacryloyl-ω-butoxy-(poly)oxyethylene, α-acryloyl-ω-methoxy-(poly)oxyethylene (poly)oxypropylene, α- And methacryloyl-ω-hydroxy-(poly)oxyethylene (poly)oxypropylene, α-methacryloyl-ω-acetyl-(poly)oxyethylene (poly)oxypropylene, and the like.

As the monomer B represented by Formula 2, one or two or more may be used, but it is preferable to use two or more, and among them, monomer B in the case where n in Formula 5 is 0 to 8 and n in Formula 5 It is preferable to contain two types of monomer B in the case of 9 to 160, and more specifically, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, It is preferable to include one or two or more monomers B selected from methyl acrylate, methyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, and butyl methacrylate and other monomers B.

Next, vinyl copolymer Q will be described. The vinyl copolymer Q is obtained by copolymerizing other monomers C copolymerizable with these in addition to the above monomers A and B. These other monomers C include 1) arylsulfonic acid, metalylsulfonic acid, alkali metal salts, alkaline earth metal salts, ammonium salts, amine salts, etc., 2) acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, sheet Acrylic acid-based monomers such as raconic acid, alkali metal salts, alkaline earth metal salts, ammonium salts, amine salts, methyl esters, ethyl esters, anhydrides, etc., 3) (meth)acrylamide, N-methyl (meth)acrylamide, N, N-dimethyl(meth)acrylamide, 2-(meth)acrylamide-2-methsulfonic acid, 2-(meth)acrylamide-2-ethanesulfonic acid, 2-(meth)acrylamide-2-propanesulfonic acid, styrene, And styrene sulfonic acid. Among these, as another monomer C, an acrylic acid monomer is preferable.

In the vinyl copolymers P and Q, the ratio of the monomer A among all the monomers to be used is preferably 1 to 99 mol%, more preferably 50 to 90 mol%. Further, the ratio of the monomer B is preferably 1 to 99 mol%, more preferably 1 to 55 mol%. Further, the ratio of the other monomer C is preferably 50 mol% or less, more preferably 25 mol% or less, and particularly preferably 10 mol% or less.

The mass average molecular weight of the vinyl copolymers P and Q is preferably 8000 to 200000, more preferably 9000 to 150000, and particularly preferably 10000 to 100000. In addition, in the present invention, the mass average molecular weight is a value in terms of polyethylene glycol by gel permeation chromatography (hereinafter referred to as GPC).

The vinyl copolymers P and Q used in the dispersion-retaining agent of the present invention can be obtained by a known method. Examples thereof include radical polymerization using water as a solvent, radical polymerization using an organic solvent as a solvent, and radical polymerization without using a solvent. Radical polymerization initiators used in such radical polymerization are decomposed under polymerization reaction temperature like peroxides such as hydrogen peroxide, ammonium persulfate, sodium persulfate and potassium persulfate, and azo compounds such as azobisisobutyronitrile, and Examples that generate curls may be mentioned, and redox initiators in which an appropriate reducing agent is used together can be mentioned. It is also possible to use a chain transfer agent in order to make the mass average molecular weight of the obtained vinyl copolymer into a desired range. The chain transfer agent is not particularly limited as long as the molecular weight of the vinyl copolymer can be adjusted, and a known chain transfer agent can be used. Specifically, 1) mercaptoethanol, thioglycerol, thioglycolic acid, mercaptopropionic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, thioglycolate octyl, 3-mercaptopropionate octyl, 2- Thiol chain transfer agents such as mercaptoethanesulfonic acid, n-dodecyl mercaptan, octyl mercaptan, and butylthioglycolate, 2) Halogen such as carbon tetrachloride, carbon tetrabromide, methylene chloride, bromoform, bromotrichloroethane Cargo, 3) unsaturated hydrocarbon compounds such as α-methylstyrene dimer, α-terpinene, γ-terpinene, dipentene and terpinolene, 4) primary alcohols such as 2-aminopropan-1-ol, isopropanol, etc. Secondary alcohols, 5) phosphorous acid, hypophosphorous acid, sodium hypophosphite, potassium hypophosphite, etc., or sulfurous acid, hydrogen sulfite, itionic acid, metabisulfite, sodium sulfite, potassium sulfite, sodium hydrogen sulfite, potassium hydrogen sulfite, Haiti Lower oxides such as sodium onate, potassium itionate, sodium metabisulfite, potassium metabisulfite, and salts thereof. In addition to the radical polymerization described above, vinyl copolymers P and Q can be obtained by anionic polymerization or cationic polymerization, and the initiators used in these polymerizations include alkali metal, butyllithium, Grignard reagent, metal alkoxide, tribromide. Lewis acids such as boron, Bronsted acids such as sulfuric acid, etc. are mentioned, but a method obtained by radical polymerization in a solvent-free or aqueous medium is preferable.

The dispersion-retaining agent of the present invention is used as an admixture in the manufacture of a hydraulic composition, for example, mortar or concrete, and sufficiently prevents slump loss of mortar or concrete produced by using it. There is no particular limitation on the material used to make mortar or concrete. For example, as a binder, 1) ordinary portland cement, quick hardening portland cement, moderate heat portland cement cement), various Portland cements such as low heat portland cement, 2) various mixed cements such as blast furnace cement, fly ash cement, and silica fume cement, 3) Alumina cement, etc. are mentioned. In addition, the water/binder ratio is also not particularly limited, but the water/binder ratio is preferably 20 to 70%, and more preferably 35 to 65%. In addition, there is no particular limitation on the types of other dispersants used in the production of mortar or concrete, but the dispersant used in combination is preferably one or two or more selected from oxycarboxylic acids or salts thereof, polycarboxylic acids or aromatic sulfonic acids. . Additives such as an AE agent, an antifoaming agent, a set retardant, a hardening accelerator, a shrinkage reducing agent, and a thickening agent may be used for the production of mortar or concrete. The amount of the dispersion-retaining agent used in the present invention is not particularly limited, but is usually 0.005 to 1.0 parts by mass, preferably 0.005 to 0.5 parts by mass, more preferably 0.01 to 0.5 parts by mass in terms of solid content per 100 parts by mass of the binder. do.

According to the dispersion retaining agent of the present invention, it is possible to sufficiently prevent slump loss of the hydraulic composition. When the dispersion-retaining agent of the present invention is used in combination with a water-soluble vinyl copolymer as described above, which has been proposed as a dispersant for a hydraulic composition, both effects are increased and excellent fluidity can be imparted to the hydraulic composition over time.

Example

Hereinafter, in order to make the configuration of the present invention more specific, examples and the like will be given, but the present invention is not limited to the above examples. In addition, in the following examples, unless otherwise indicated,% means mass %, and parts mean mass parts.

Test Category 1 (Synthesis of Monomer A)

Synthesis of monomer (A-5)

127.7 g of hydroxyethyl acrylate, 192.1 g of trimellitic anhydride, 0.64 g of 4-methoxyphenol, and 300 ml of pyridine were placed in a reaction vessel equipped with a thermometer, agitator, and an air introduction tube, uniformly dissolved while stirring, and dried. The temperature was raised while blowing air at a flow rate of 5 ml/min, and the reaction was carried out at 80°C for 8 hours. After completion of the reaction, pyridine was evaporated with an evaporator to obtain a monoester body (A-5) of hydroxyethyl acrylate and trimellitic acid.

Synthesis of monomer (A-6)

130.1 g of hydroxypropyl acrylate, 110.1 g of succinic anhydride, and 0.13 g of phenothiazine were placed in a reaction vessel equipped with a thermometer, agitator, and an air introduction tube, and the temperature was raised while blowing dry air at a flow rate of 3 ml/min. It was reacted at °C for 10 hours. It cooled after completion|finish of reaction, and obtained the monoester body (A-6) of hydroxypropyl acrylate and succinic anhydride.

・Test Category 2 (Synthesis of vinyl copolymer)

Example 1 (synthesis of vinyl copolymer (EX-1), etc.)

29.2 g of ion-exchanged water, 174.2 g of α-(3-methyl-3-butenyl)-ω-hydroxy-poly(n=53)oxyethylene, a reaction vessel equipped with a thermometer, stirrer, dropping funnel, and nitrogen inlet tube And uniformly dissolved while stirring, the atmosphere was replaced with nitrogen, and the temperature of the reaction system was set to 65°C in a hot water bath. Next, 10.8 g of 3.5% hydrogen peroxide solution was added dropwise over 3 hours, and an aqueous solution in which 15.2 g of 2-acryloyloxyethyl succinic acid and 28.3 g of hydroxyethyl acrylate were suspended in 174.2 g of ion-exchanged water was added in 3 hours. It was dripped over, and an aqueous solution in which 1.0 g of L-ascorbic acid and 0.8 g of mercaptoethanol were dissolved in 7.3 g of ion-exchanged water was added dropwise over 4 hours. Thereafter, the temperature was maintained at 65° C. for 2 hours, and the polymerization reaction was terminated. After completion of the polymerization reaction, a 30% aqueous sodium hydroxide solution was added to adjust the pH to 6, and the concentration was adjusted to 40% with ion-exchanged water to obtain an aqueous solution of the reactant. This reaction product was used as a vinyl copolymer (EX-1).

Example 2 (Synthesis of vinyl copolymer (EX-2))

Ion-exchanged water 206.5 g, α-methacryloyl-ω-methoxy-poly (n=23) oxyethylene 151.7 g, 2-methacryloyloxyethylsuccinic acid 23.3 g and hydroxyethyl acrylate 19.4 g, 3 -2.3 g of mercaptopropionic acid was placed in the same reaction vessel as in Example 1, the atmosphere was replaced with nitrogen while stirring, and the temperature of the reaction system was set to 70° C. in a hot water bath. A 28.0 g aqueous solution of 3.0% sodium peroxide was added to initiate the reaction. 3 hours after the initiation of the reaction, an aqueous solution of 6.8 g of 3.0% sodium persulfate was added, and the polymerization reaction was completed by maintaining at 70°C for 3 hours. Thereafter, a 30% aqueous sodium hydroxide solution was added to adjust the pH to 6, and the concentration was adjusted to 40% with ion-exchanged water to obtain an aqueous solution of the reactant. This reaction product was used as a vinyl copolymer (EX-2).

Example 3 (Synthesis of vinyl copolymer (EX-3))

27.9 g of ion-exchanged water and 173.0 g of α-(3-methyl-3-butenyl)-ω-hydroxy-poly(n=53)oxyethylene were added to the same reaction vessel as in Example 1, and uniformly dissolved while stirring. Thereafter, the atmosphere was replaced with nitrogen, and the temperature of the reaction system was set to 65°C in a hot water bath. Next, 10.8 g of 3.5% hydrogen peroxide solution was added dropwise over 3 hours, and at the same time, an aqueous solution in which 43.2 g of 2-acryloyloxyethylsuccinic acid was suspended in 173.0 g of ion-exchanged water was added dropwise over 3 hours. An aqueous solution in which 0.9 g of L-ascorbic acid and 0.7 g of 3-mercaptopropionic acid were dissolved in 6.1 g of water was added dropwise over 4 hours. Thereafter, the temperature was maintained at 65° C. for 2 hours, and the polymerization reaction was terminated. After completion of the polymerization reaction, a 30% aqueous sodium hydroxide solution was added to adjust the pH to 6, and the concentration was adjusted to 40% with ion-exchanged water to obtain an aqueous solution of the reactant. This reaction product was used as a vinyl copolymer (EX-3).

Example 4 (Synthesis of vinyl copolymer (EX-4))

36.4 g of ion-exchanged water, 173.5 g of α-(3-methyl-3-butenyl)-ω-hydroxy-poly(n=53)oxyethylene were placed in the same reaction vessel as in Example 1, and uniformly dissolved while stirring. Thereafter, the atmosphere was replaced with nitrogen, and the temperature of the reaction system was set to 65°C in a hot water bath. Next, 9.8 g of 4.0% hydrogen peroxide solution was added dropwise over 3 hours, and 15.2 g of 2-acryloyloxyethylsuccinic acid, 26.0 g of hydroxyethyl acrylate and 2.2 g of acrylic acid were dissolved in 164.8 g of ion-exchanged water. An aqueous solution was added dropwise over 3 hours, and an aqueous solution obtained by dissolving 0.9 g of L-ascorbic acid and 1.1 g of 3-mercaptopropionic acid in 7.8 g of ion-exchanged water was added dropwise over 4 hours. Thereafter, the temperature was maintained at 65° C. for 2 hours, and the polymerization reaction was terminated. After completion of the polymerization reaction, a 30% aqueous sodium hydroxide solution was added to adjust the pH to 6, and the concentration was adjusted to 40% with ion-exchanged water to obtain an aqueous solution of the reactant. This reaction product was used as a vinyl copolymer (EX-4).

Examples 5 to 9 (synthesis of vinyl copolymers (EX-5) to (EX-9))

In the same manner as in Examples 1 to 4, vinyl copolymers (EX-5) to (EX-9) were synthesized by changing the types and amounts of monomers used only as described in Table 1.

Comparative Example 1 (Synthesis of vinyl copolymer (CE-1))

242.8 g of ion-exchanged water, 370.0 g of α-(3-methyl-3-butenyl)-ω-hydroxy-poly(n=53)oxyethylene, and 0.7 g of acrylic acid were added to the same reaction vessel as in Example 1, and stirred. While uniformly dissolving, the atmosphere was replaced with nitrogen, and the temperature of the reaction system was set to 60°C in a hot water bath. Next, 48.8 g of a 4.3% sodium persulfate aqueous solution was added dropwise over 3.5 hours, while an aqueous solution in which 18.7 g of acrylic acid was dissolved in 21.6 g of ion-exchanged water was added dropwise over 3 hours, and mercapto was added to 46.7 g of ion-exchanged water. An aqueous solution in which 0.7 g of ethanol was dissolved was added dropwise over 3.5 hours. After that, the temperature was maintained at 60° C. for 2 hours, and the polymerization reaction was terminated. After completion of the polymerization reaction, a 30% aqueous sodium hydroxide solution was added to adjust the pH to 6, and the concentration was adjusted to 40% with ion-exchanged water to obtain an aqueous solution of the reactant. This reaction product was used as a vinyl copolymer (CE-1).

Comparative Example 2 (Adjustment of vinyl copolymer (CE-2))

The concentration of sodium gluconate was adjusted to 40% with ion-exchanged water.

For each vinyl copolymer synthesized above, its composition and mass average molecular weight are put together in Table 1 and shown. In addition, for each vinyl copolymer, after removing water from the aqueous solution, the solution was adjusted to 5% with heavy water, and measured by 300 MHz NMR to confirm that each monomer was polymerized. In addition, the mass average molecular weight was expressed in terms of polyethylene glycol by GPC.

In Table 1,

A-1: 2-acryloyloxyethylsuccinic acid

A-2: 2-methacryloyloxyethylsuccinic acid

A-3: 2-acryloyloxyethyl hexahydrophthalic acid

A-4: 2-acryloyloxyethylphthalic acid

A-5: Monoester of hydroxyethylacrylate and trimellitic acid

A-6: Monoester of hydroxypropylacrylate and succinic acid

M-1: α-(3-methyl-3-butenyl)-ω-hydroxy-poly(n=53)oxyethylene

M-2: α-methacryloyl-ω-methoxy-poly (n=23) oxyethylene

M-3: α-methacryloyl-ω-methoxy-poly(n=45)oxyethylene

M-4: α-metaryl-ω-hydroxy-poly (n=113) oxyethylene

M-5: α-methacryloyl-ω-methoxy-poly (n=9) oxyethylene

M-6: hydroxyethyl acrylate

M-7: methyl acrylate

M-8: hydroxypropyl acrylate

C-1: acrylic acid

C-2: methacrylic acid

・Test category 3 (evaluation as a dispersant for hydraulic compositions)

·Manufacture of concrete

Portland cement (manufactured by Pacific Cement, specific gravity=3.16), fine aggregate (Oigawa water system, specific gravity=2.58) and coarse aggregate (Okazaki crushed stone, specific gravity=2.68) are sequentially added to a 55L forced twin-screw mixer and kneaded for 5 seconds. (dry mixed), a high-performance AE water reducing agent (trade name Chupol HP-11 manufactured by Takemoto Yuji Co., hereinafter referred to as H-11) so that the target slump is in the range of 21 ± 1.5 cm and air volume in the range of 4.5 ± 0.5% 0.6% to 0.8%, a 20% aqueous solution of vinyl copolymers (EX-1) to (EX-9) and (CE-1), (CE-2) synthesized in Test Category 2 is usually 0.1 to 0.1 to Portland cement. When kneading so that 0.3%, AE (trade name AE-300 manufactured by Takemoto Yuji Co., Ltd.) is 0.005% for normal Portland cement, and antifoaming agent (brand name AFK-2 manufactured by Takemoto Yuji Co., Ltd.) is 0.001% normal Portland cement, with water It was added and kneaded for 90 seconds. The unit amount and the like of the thus prepared concrete are summarized and shown in Table 2.

·evaluation

The slump flow, air volume, compressive strength and bleeding rate after 24 hours of each concrete left at intervals of 30 minutes from immediately after kneading were measured as follows, and the results are summarized in Table 3.

Slump flow: Measurement was made in accordance with JIS-A1150 for each concrete that was left standing immediately after kneading and at intervals of 30 minutes.

-Air quantity: Measured according to JIS-A1128 for each concrete that was left to stand immediately after kneading and at intervals of 30 minutes.

Compressive strength: According to JIS-A1108, the specimen dimensions were 100 mm in diameter x 200 mm in height, and measured at 24 hours of material age.

-Bleeding rate: Measured according to JIS-A1123.

In Table 3,

Addition ratio of HP-11 (%):% by mass with respect to normal Portland cement in the presence of HP-11

Addition ratio of vinyl copolymer (%):% by mass of a 20% aqueous solution of the vinyl copolymer synthesized in Test Category 2 with respect to ordinary Portland cement

Even in the results of Table 3 corresponding to Tables 1 and 2, according to the dispersion-retaining agent of the present invention, it is possible to maintain the fluidity of the hydraulic composition for a long time without causing a curing delay.

Claims (7)

A dispersion-retaining agent for a hydraulic composition comprising a vinyl copolymer obtained from monomer A represented by the following formula (1) and monomer B represented by the following formula (2):
[Formula 1]

[Formula 2]

(In Formula 1 and Formula 2,
R ¹ , R ² : hydrogen atom, methyl group, or organic group represented by Formula 3
p: 0 or 1
X: an organic group represented by the following formula (4)
Y: an organic group represented by the following formula (5)
M ¹ : hydrogen atom, ammonium group, organic amine group, alkali metal or 1/2 equivalent of alkaline earth metal)
[Formula 3]

(In Formula 3,
r: 0 or 1
M ² : hydrogen atom, ammonium group, organic amine group, alkali metal or 1/2 equivalent of alkaline earth metal)
[Formula 4]

(In Formula 4,
AO: C2-C4 oxyalkylene group
m: an integer from 1 to 10
R ³ : Alkylene group, aromatic ring group or unsaturated hydrocarbon group which may have a hetero atom)
[Formula 5]

(In Formula 5,
s: an integer from 0 to 4
t: 0 or 1
AO: C2-C4 oxyalkylene group
n: an integer from 0 to 300
R ⁴ : A hydrogen atom, an alkyl group having 1 to 22 carbon atoms, or an aliphatic acyl group having 1 to 22 carbon atoms (however, when n=0, R ⁴ is an alkyl group having 1 to 22 carbon atoms or an aliphatic acyl group having 1 to 22 carbon atoms). A dispersion-retaining agent for a hydraulic composition comprising a vinyl copolymer obtained from the monomer A of claim 1, the monomer B of claim 1, and another monomer C copolymerizable with these monomers. The dispersion-retaining agent for a hydraulic composition according to claim 1 or 2, wherein R ³ in Formula 4 is an organic group represented by Formula 6 below:
[Formula 6]

(In Formula 6,
R ⁵ : C1-C22 alkylene group, aromatic cyclic group, or unsaturated hydrocarbon group which may have a hetero atom
u: an integer from 0 to 2
M ³ : hydrogen atom, ammonium group, organic amine group, alkali metal or 1/2 equivalent of alkaline earth metal). The dispersion-retaining agent for hydraulic compositions according to claim 3, wherein R ⁵ in Formula 6 is an alkylene group having 1 to 6 carbon atoms, an aromatic cyclic group or an unsaturated hydrocarbon group. The dispersion-retaining agent for hydraulic compositions according to claim 1 or 2, wherein the monomer A is a condensation product of hydroxyethyl (meth)acrylate and dibasic, tribasic, or tetrabasic carboxylic anhydride. The dispersion-retaining agent for hydraulic compositions according to claim 1 or 2, wherein the vinyl copolymer has a mass average molecular weight of 8000 to 200000. The method according to claim 1, wherein the vinyl copolymer has 1 to 99 mol% of the constituent units derived from monomer A and 1 to 99 mol% (100 mol% in total) of the constituent units derived from monomer B among the total constituent units. That, a dispersion-retaining agent for hydraulic compositions.