WO2019053782A1 - Dispersion-maintaining agent for hydraulic composition - Google Patents

Abstract

The invention provides a dispersion-maintaining agent for a hydraulic composition which makes it possible to maintain the fluidity of a hydraulic composition, and which presents little risk of retardation of curing, even after a long period of time after mixing. A vinyl copolymer in which are copolymerized a specific monomer having a carboxyl group in each molecule, a specific monomer having a polyoxyalkylene glycol residue in each molecule, and if necessary, another monomer allowing copolymerization with these monomers, is put into is used as a dispersion-maintaining agent for hydraulic composition.

Description

Dispersion holding agent for hydraulic composition

The present invention relates to a dispersion holding agent for hydraulic compositions. Various dispersants are widely used in the preparation of hydraulic compositions such as mortar and concrete. However, in general, when a hydraulic composition is prepared using a dispersant, slump loss (decrease in flowability with time) is large and workability and workability are reduced. The present invention relates to a dispersion holding agent for a hydraulic composition which can sufficiently prevent slump loss.

Heretofore, dispersants for hydraulic compositions comprising a water-soluble vinyl copolymer have been proposed as having slump loss prevention performance per se (see, for example, Patent Documents 1 to 4). However, these conventional proposals have a problem that the slump loss of the prepared hydraulic composition can not be sufficiently prevented. Then, what combined the slump loss prevention agent with the dispersing agent for hydraulic composition is also proposed (for example, refer patent document 5). However, even with this conventional proposal, there is still a problem that the slump loss of the prepared hydraulic composition can not be sufficiently prevented.

Japanese Patent Application Laid-Open No. 63-285140 Japanese Patent Application Laid-Open No. 1-226757 Japanese Patent Application Laid-Open No. 10-67549 JP 2003-335562 Japanese Patent Application Publication No. 2003-34565

The problem to be solved by the present invention is to provide a dispersion holding agent for a hydraulic composition, which can maintain the fluidity of the hydraulic composition even after a long time since kneading, and which is less delayed in curing. is there.

Therefore, as a result of researches to solve the above-mentioned problems, the present inventors found that a specific monomer having a carboxyl group in the molecule and a specific monomer having a polyalkylene glycol residue in the molecule. Furthermore, it has been found that vinyl copolymers obtained by copolymerizing these monomers with other monomers copolymerizable with these monomers are properly suitable as dispersion holding agents for hydraulic compositions, if necessary. The

That is, the present invention comprises a vinyl copolymer obtained from a monomer A represented by the following chemical formula 1 and a monomer B represented by the following chemical formula 2, for a hydraulic composition It relates to the dispersion holding agent. Further, the present invention is obtained from a monomer A represented by the following chemical formula 1, a monomer B represented by the following chemical formula 2, and another monomer C copolymerizable with these monomers. The present invention relates to a dispersion-retaining agent for a hydraulic composition, characterized by containing a vinyl copolymer as described above.

In chemical formulas 1 and 2,
R ¹ , R ² : a hydrogen atom, a methyl group or an organic group p: 0 or 1 represented by the following chemical formula 3
X: organic group represented by the following chemical formula 4 Y: organic group represented by the following chemical formula 5 M ¹ : hydrogen atom, ammonium group, organic amine group, alkali metal or 1/2 equivalent alkaline earth metal

In chemical 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

In Formula 4,
AO: an oxyalkylene group having 2 to 4 carbon atoms m: an integer of 1 to 10 R ³ : an alkylene group which may have a hetero atom, an aromatic ring group or an unsaturated hydrocarbon group

In Formula 5,
s: integer from 0 to 4 t: 0 or 1
AO: an oxyalkylene group having a carbon number of 2 to 4 n: an integer of 0 to 300 R ⁴ : a hydrogen atom, an alkyl group having a carbon number of 1 to 22 or an aliphatic acyl group having a carbon number of 1 to 22 When R ⁴ is an alkyl group having 1 to 22 carbon atoms or an aliphatic acyl group having 1 to 22 carbon atoms)

The dispersion holding agent for a hydraulic composition according to the present invention (hereinafter referred to as the dispersion holding agent of the present invention) includes a monomer A shown in the above-mentioned chemical formula 1 and a monomer B shown in the above-mentioned chemical formula 2 And a monomer containing vinyl copolymer (hereinafter referred to as vinyl copolymer P), such monomer A, such monomer B, and other monomers C copolymerizable therewith. And those containing a vinyl copolymer (hereinafter referred to as vinyl copolymer Q) obtained from

First, the vinyl copolymer P will be described. The vinyl copolymer P is a vinyl copolymer obtained from the monomer A and the monomer B, and the ratio of the both is not particularly limited. Preferred are vinyl copolymers having a weight average molecular weight of 8,000 to 200,000, having a ratio of 1 to 99 mol% of structural units and 1 to 99 mol% (total of 100 mol%) of structural units derived from monomer B.

In the above Chemical Formula 1 showing monomer A, R ¹ is a hydrogen atom, a methyl group or an organic group shown by Chemical Formula 3 above, p is 0 or 1 and X is an organic group shown by Chemical Formula 4 above, M ¹ is a hydrogen atom, an ammonium group, an organic amine group, an alkali metal or a half equivalent of an alkaline earth metal. In the formula 3, r is 0 or 1, and M ² is a hydrogen atom, an ammonium group, an organic amine group, an alkali metal or a half equivalent alkaline earth metal, but the organic group shown in the formula 3 is Is a carboxyl group or a methylene carboxyl group.

Further, in the chemical 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 which may have a hetero atom, an aromatic ring group or an unsaturated hydrocarbon.

In Chemical formula 4, as the oxyalkylene group of AO, an oxyethylene group, an oxypropylene group and an oxybutylene group may be mentioned, but an oxyethylene group and an oxypropylene group are preferable, and an oxyethylene group is more preferable. These may be one kind or two or more kinds. 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 which may have a hetero atom, an aromatic ring group or an unsaturated hydrocarbon group, and the number of carbon atoms thereof is not particularly limited. Examples of the alkylene group which may have a hetero atom include methylene group, ethylene group, propylene group, butylene group, cyclohexyl group, oxymethylene group, oxyethylene group, oxypropylene group, oxybutylene group and the like. Moreover, as an aromatic ring group which may have a hetero atom, phenylene group, tolylene group, naphthylene group, thiophene, furan, pyrrole, benzothiophene, benzofuran, benzopyrrole, triazine, imidazole, benzoimidazole, triazole, thiazole, thiazole, etc. Can be mentioned. Furthermore, examples of the unsaturated hydrocarbon group which may have a hetero atom include ethynyl group, propynyl group, butynyl group, and groups having a carbonyl group or an imino group before or after these groups, and organic compounds represented by the following chemical formula 6 Groups are preferred.

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

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

In the formulas (1), (2) and (3), M ¹ , M ² and M ³ are a hydrogen atom, an ammonium group, an organic amine group, an alkali metal or a half equivalent alkaline earth metal. These may be one kind or two or more kinds. Examples of the ammonium group include ammonium group, tetramethyl ammonium group, tetrabutyl ammonium group and the like. As the organic amine group, alkylamine groups such as methylamine group, dimethylamine group, trimethylamine group and triethylamine group, alkanolamine groups such as diethanolamine group and triethanolamine group, and aromatic amine groups such as pyridinium group and rutidinium group Can be mentioned. Further, as the alkali metal, lithium, sodium, potassium, cesium and the like can be mentioned. And, as the alkaline earth metal, calcium, magnesium, barium and the like can be mentioned. However, in the case of an 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 hexahydrophthalic acid, 2-acryloyloxyethyl phthalic acid And the like, and also a condensation product of an unsaturated carboxylic acid ester having a hydroxyl group at an end such as hydroxyethyl (meth) acrylate, polyoxyethylene mono (meth) acrylic acid ester, and a 2- to 4-basic carboxylic acid anhydride Can be mentioned. Such a condensate is obtained by the condensation of an unsaturated carboxylic acid ester having a hydroxyl group at an end with a 2 to 4 basic carboxylic acid anhydride. Examples of unsaturated carboxylic acid esters that can be used for condensation include hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, polyoxyalkylene mono (meth) acrylate, etc. It can be mentioned. Moreover, as a 2- to 4-basic carboxylic acid anhydride which can be used for condensation, succinic acid anhydride, maleic acid anhydride, trimellitic acid anhydride, cyclohexyl 1, 2 dicarboxylic acid anhydride, pyromellitic acid anhydride, etc. Can be mentioned. As the monomer A, one or more of such condensates can be used, but a condensate of hydroxyethyl (meth) acrylate and a 2- to 4-basic carboxylic acid anhydride is preferred.

The above condensates can be obtained by known methods. For example, a method of heating and stirring an unsaturated carboxylic acid ester having a hydroxyl group at the end and a 2 to 4 basic carboxylic acid anhydride in the absence of a solvent, an unsaturated carboxylic acid having a hydroxyl group at the end in the presence of a solvent and a condensing agent There is a method of condensing an acid ester and a 2 to 4 basic carboxylic acid anhydride.

In the above-mentioned chemical formula 2 showing monomer B, R ² is a hydrogen atom, a methyl group or an organic group shown by chemical formula 3 above, and Y is an organic group shown by chemical formula 5 above. In the chemical 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, 1 to 22 carbon atoms It is an alkyl group 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.

As R ^{4 in} Chemical Formula 5, 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, helicosyl 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-octyl-dodecyl group, 2-nonyl group -Tridecyl, 2-decyl-tetradecyl, 2-undecyl-pentadecyl Group, alkyl group having 1 to 22 carbon atoms such as 2-dodecyl-hexadecyl group, 3) formyl group, acetyl group, propanoyl group, butanoyl group, hexanoyl group, heptanoyl group, octanoyl group, nonanoyl group, decanoyl group, hexadeca Examples thereof include aliphatic acyl groups having 1 to 22 carbon atoms such as noyl group, octadecanoyl group, hexadecenoyl group, eicosenoyl group and octadecenoyl group. Among them, 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 Chemical Formula 5 is as described above for AO in Chemical formula 4, and n is an integer of 0 to 300, and as (AO) n, 0 to 160 oxyethylene units and / or oxypropylene A (poly) oxyalkylene group composed of units 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, methacrylate Butyl, α-allyl-ω-acetyl- (poly) oxyethylene, α-allyl-ω-acetyl- (poly) oxyethylene (poly) oxypropylene, α-allyl-ω-hydroxy- (poly) oxyethylene, α -Allyl-ω-hydroxy- (poly) oxyethylene (poly) oxypropylene, α-methallyl-ω-hydroxy- (poly) oxyethylene, α-methallyl-ω-methoxy- (poly) oxyethylene, α-methallyl- ω-hydroxy- (po I) Oxyethylene (poly) oxypropylene, -methallyl-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) oxypropyle Ren, α-methacryloyl-ω-hydroxy- (poly) oxyethylene, α-methacryloyl-ω-methoxy- (poly) oxyethylene, α-methacryloyl-ω-butoxy- (poly) oxyethylene, α-acryloyl-ω- Methoxy- (poly) oxyethylene (poly) oxypropylene, α-methacryloyl-ω-hydroxy- (poly) oxyethylene (poly) oxypropylene, α-methacryloyl-ω-acetyl- (poly) oxyethylene (poly) oxypropylene Etc.

As the monomer B shown in Chemical formula 2, one or two or more kinds can be used, but it is preferable to use two or more, and in particular, when n in the chemical formula 5 is 0 to 8, a single amount Those containing two types of monomer B when n in the compound B and compound 9 is 9 to 160 are preferable, and more specifically, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate Preferably contain one or more monomer B selected from methyl acrylate, methyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate and butyl methacrylate and another monomer B .

Next, the vinyl copolymer Q will be described. The vinyl copolymer Q is obtained by copolymerizing another monomer C copolymerizable therewith, in addition to the monomer A and the monomer B described above. As such other monomer C, 1) allyl sulfonic acid, methallyl sulfonic acid, alkali metal salts thereof, alkaline earth metal salts, ammonium salts, amine salts etc., 2) acrylic acid, methacrylic acid, crotonic acid And acrylic acid monomers such as maleic acid, fumaric acid, itaconic acid and citraconic acid, alkali metal salts thereof, 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) acrylamido-2-metasulfonic acid, 2- (meth) acrylamido-2-ethanesulfonic acid, 2 And (meth) acrylamido-2-propanesulfonic acid, styrene, styrenesulfonic acid and the like. Among them, as another monomer C, an acrylic acid type monomer is preferable.

In the vinyl copolymers P and Q, the proportion of the monomer A in the total monomers used is preferably 1 to 99 mol%, more preferably 50 to 90 mol%. The proportion of the monomer B is preferably 1 to 99% by mole, and more preferably 1 to 55% by mole. Furthermore, the proportion 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 8,000 to 200,000, more preferably 9,000 to 150,000, and particularly preferably 10,000 to 100,000. In the present invention, the mass average molecular weight is a value in terms of polyethylene glycol calculated by gel permeation chromatography (hereinafter referred to as GPC).

The vinyl copolymers P and Q to be provided for the dispersion holding agent of the present invention can be obtained by known methods. Examples thereof include radical polymerization using water as a solvent, radical polymerization using an organic solvent as a solvent, radical polymerization using no solvent, and the like. Such radical polymerization initiators for use in such radical polymerization include peroxides such as hydrogen peroxide, ammonium persulfate, sodium persulfate and potassium persulfate, and azo compounds such as azobisisobutyronitrile at a polymerization reaction temperature. Those which decompose and generate radicals, and optionally include redox initiators which use reducing agents together. A chain transfer agent can also be used to bring the mass average molecular weight of the resulting vinyl copolymer into the desired range. The chain transfer agent is not particularly limited as long as it can adjust the molecular weight of the vinyl copolymer, and known chain transfer agents can be used. Specifically, 1) mercaptoethanol, thioglycerol, thioglycolic acid, mercaptopropionic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, octyl thioglycollate, octyl 3-mercaptopropionate, 2- Thiol-based chain transfer agents such as mercaptoethane sulfonic acid, n-dodecyl mercaptan, octyl mercaptan and butyl thioglycolate 2) Carbon tetrachloride, carbon tetrabromide, halides such as methylene chloride, bromoform and bromotrichloroethane 3) unsaturated hydrocarbon compounds such as α-methylstyrene dimer, α-terpinene, γ-terpinene, dipentene and terpinorene 4) primary alcohols such as 2-aminopropan-1-ol secondary alcohols such as isopropanol 5 ) Acid, hypophosphorous acid, sodium hypophosphite, potassium hypophosphite, etc., sulfite, hydrogen sulfite, dithionite, metabisulfite, sodium sulfite, potassium sulfite, sodium bisulfite, potassium bisulfite, Examples thereof include lower oxides such as sodium dithionite, potassium dithionite, sodium metabisulfite and potassium metabisulfite and salts thereof. The vinyl copolymers P and Q can also be obtained by anionic polymerization or cationic polymerization in addition to the radical polymerization described above, and as an initiator used for these polymerizations, alkali metals, butyl lithium, Grignard reagents, metals Examples thereof include alkoxides, Lewis acids such as boron trifluoride, and Bronsted acids such as sulfuric acid, but a method obtained by radical polymerization in a solvent-free or aqueous solvent is preferable.

The dispersion holding agent of the present invention is used as an admixture during preparation of a hydraulic composition such as mortar and concrete, and the slump loss of the mortar and concrete prepared using this is sufficiently prevented. There is no particular limitation on the materials used for preparation of mortar and concrete. For example, as a binder, 1) various portland cements such as ordinary portland cement, early strength portland cement, moderate heat portland cement, low heat portland cement, 2) blast furnace cement, Various mixed cements such as fly ash cement and silica fume cement, 3) alumina cement and the like can be mentioned. The water / binder ratio is also not particularly limited, but the water / binder ratio is preferably 20 to 70%, more preferably 35 to 65%. Further, the type of other dispersants used for preparation of mortar and concrete is not particularly limited, but the dispersant to be used in combination is selected from oxycarboxylic acids and salts thereof, polycarboxylic acids and aromatic sulfonic acids. One or two or more are preferable. In the preparation of mortar and concrete, additives such as an AE agent, an antifoaming agent, a setting retarder, a hardening accelerator, a shrinkage reducing agent, and a thickener can also be used. The amount of the dispersion holding agent used in the present invention is not particularly limited, but it is usually 0.005 to 1.0 parts by mass, preferably 0.005 to 1.0 parts by mass in terms of solid content per 100 parts by mass of the binder. The amount is 0.5 parts by mass, more preferably 0.01 to 0.5 parts by mass.

According to the dispersion holding agent of the present invention, slump loss of the hydraulic composition can be sufficiently prevented. When the dispersion holding agent of the present invention is used in combination with a water-soluble vinyl copolymer as described above, which has been conventionally proposed as a dispersant for hydraulic compositions, both effects combine, and temporally in hydraulic compositions as well. It can provide excellent liquidity.

Hereinafter, examples and the like will be described in order to make the configuration of the present invention more specifically, but the present invention is not limited to the examples. In the following Examples etc., unless otherwise indicated,% means mass%, and a part means mass part.

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 equipped with a thermometer, a stirrer, and an air introduction tube The reaction vessel was charged and dissolved uniformly with stirring, and then heated while raising dry air at a flow rate of 5 mL / min, and reacted at a temperature of 80 ° C. for 8 hours. After completion of the reaction, pyridine was distilled off with an evaporator to obtain a monoester (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 charged in a reaction vessel equipped with a thermometer, a stirrer and an air introduction tube and dried The temperature was raised while blowing air at a flow rate of 3 mL / min, and the reaction was allowed to proceed at 100 ° C. for 10 hours. After completion of the reaction, the reaction solution was cooled to obtain a monoester form (A-6) of hydroxypropyl acrylate and succinic acid.

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 were equipped with a thermometer, a stirrer, a dropping funnel, and a nitrogen inlet tube After charging into a reaction vessel and dissolving uniformly while stirring, the atmosphere was replaced with nitrogen, and the temperature of the reaction system was brought to 65 ° C. with a warm water bath. Next, 10.8 g of 3.5% hydrogen peroxide water is dropped over 3 hours, and 15.2 g of 2-acryloyloxyethyl succinic acid and 28.3 g of hydroxyethyl acrylate are suspended in 174.2 g of ion-exchanged water. The resulting aqueous solution was dropped over 3 hours, 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 exchange was dropped over 4 hours. Thereafter, the temperature was maintained at 65 ° C. for 2 hours to complete the polymerization reaction. After completion of the polymerization reaction, a 30% aqueous sodium hydroxide solution was added to adjust to pH 6, and the concentration was adjusted to 40% with ion exchanged water to obtain an aqueous liquid of a reaction product. This reaction product was designated as vinyl copolymer (EX-1).

Example 2 {Synthesis of Vinyl Copolymer (EX-2)}
206.5 g of ion-exchanged water, 151.7 g of α-methacryloyl-ω-methoxy-poly (n = 23) oxyethylene, 23.3 g of 2-methacryloyloxyethyl succinic acid and 19.4 g of hydroxyethyl acrylate, 3-mercaptopropion In a reaction vessel similar to that of Example 1, 2.3 g of acid was charged, the atmosphere was replaced with nitrogen while stirring, and the temperature of the reaction system was adjusted to 70 ° C. with a hot water bath. The reaction was initiated by adding an aqueous solution of 28.0 g of 3.0% sodium persulfate. Three hours after initiation of the reaction, an aqueous solution of 6.8 g of 3.0% sodium persulfate was added, and the temperature was maintained at 70 ° C. for 3 hours to complete the polymerization reaction. Thereafter, a 30% aqueous sodium hydroxide solution was added to adjust to pH 6, and the concentration was adjusted to 40% with ion exchanged water to obtain an aqueous solution of a reaction product. The 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 charged in the same reaction vessel as in Example 1 and homogenized while stirring. The atmosphere was replaced with nitrogen, and the temperature of the reaction system was brought to 65.degree. C. with a warm water bath. Next, while adding 10.8 g of 3.5% hydrogen peroxide water dropwise over 3 hours, an aqueous solution in which 43.2 g of 2-acryloyloxyethyl succinic acid is suspended in 173.0 g of ion-exchanged water is taken over 3 hours An aqueous solution prepared by dissolving 0.9 g of L-ascorbic acid and 0.7 g of 3-mercaptopropionic acid in 6.1 g of ion exchange was dropped over 4 hours. Thereafter, the temperature was maintained at 65 ° C. for 2 hours to complete the polymerization reaction. After completion of the polymerization reaction, a 30% aqueous sodium hydroxide solution was added to adjust to pH 6, and the concentration was adjusted to 40% with ion exchanged water to obtain an aqueous liquid of a reaction product. The 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 and 173.5 g of α- (3-methyl-3-butenyl) -ω-hydroxy-poly (n = 53) oxyethylene were charged in the same reaction vessel as in Example 1 and homogenized while stirring. The atmosphere was replaced with nitrogen, and the temperature of the reaction system was brought to 65.degree. C. with a warm water bath. Next, 9.8 g of 4.0% hydrogen peroxide water is added dropwise over 3 hours, and 15.2 g of 2-acryloyloxyethyl succinic acid, 26.0 g of hydroxyethyl acrylate, and acrylic acid 2 in 164.8 g of ion-exchanged water An aqueous solution in which 2 g was dissolved was dropped over 3 hours, and an aqueous solution in which 0.9 g of L-ascorbic acid and 1.1 g of 3-mercaptopropionic acid were dissolved in 7.8 g of ion exchange was dropped over 4 hours . Thereafter, the temperature was maintained at 65 ° C. for 2 hours to complete the polymerization reaction. After completion of the polymerization reaction, a 30% aqueous sodium hydroxide solution was added to adjust to pH 6, and the concentration was adjusted to 40% with ion exchanged water to obtain an aqueous liquid of a reaction product. The reaction product was used as a vinyl copolymer (EX-4).

Examples 5 to 9 {Synthesis of Vinyl Copolymer (EX-5) to (EX-9)}
Vinyl copolymers (EX-5) to (EX-9) were synthesized in the same manner as in Examples 1 to 4 except that the kind, amount, etc. of the used monomers were changed as described in Table 1. did.

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, 0.7 g of acrylic acid were placed in the same reaction vessel as in Example 1. After being charged and dissolved uniformly while stirring, the atmosphere was replaced with nitrogen, and the temperature of the reaction system was adjusted to 60 ° C. with a warm water bath. Next, 48.8 g of a 4.3% aqueous solution of sodium persulfate is dropped over 3.5 hours, and an aqueous solution in which 18.7 g of acrylic acid is dissolved in 21.6 g of ion-exchanged water is dropped over 3 hours, An aqueous solution prepared by dissolving 0.7 g of mercaptoethanol in 46.7 g of ion exchange was dropped over 3.5 hours. Thereafter, the temperature was maintained at 60 ° C. for 2 hours to complete the polymerization reaction. After completion of the polymerization reaction, a 30% aqueous sodium hydroxide solution was added to adjust to pH 6, and the concentration was adjusted to 40% with ion exchanged water to obtain an aqueous liquid of a reaction product. This reaction product was designated as vinyl copolymer (CE-1).

・ Comparative example 2 {adjustment of CE-2}
Sodium gluconate was adjusted to a concentration of 40% with ion exchange water.

The composition and mass average molecular weight of each of the vinyl copolymers synthesized as described above are summarized in Table 1. In addition, about each vinyl copolymer, after removing water from the aqueous solution, a solution is adjusted so that it may become 5% with heavy water, it measures by NMR of 300 MHz, and each monomer polymerizes. I confirmed that it was. Moreover, the mass mean molecular weight was shown by polyethylene glycol conversion by GPC.

In Table 1,
A-1: 2-acryloyloxyethylsuccinic acid A-2: 2-methacryloyloxyethylsuccinic acid A-3: 2-acryloyloxyethylhexahydrophthalic acid A-4: 2-acryloyloxyethyl phthalic acid A-5: Monoester of hydroxyethyl acrylate and trimellitic acid A-6: Monoester of hydroxypropyl acrylate 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 -Methallyl-ω-hydroxy-poly (n = 113) oxyethylene M-5: α-methacryloyl-ω-methoxy-poly (n = 9 Polyoxyethylene 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 dispersant for hydraulic composition)
Preparation of concrete 55L forced biaxial mixer with ordinary portland cement (Pacific Cement Co., Ltd., specific gravity = 3.16), fine aggregate (Oikawa water sand, specific gravity = 2.58) and coarse aggregate (Okazaki crushed stone, High performance AE water reducing agent so that target slump becomes 21 ± 1.5 cm and air amount becomes 4.5 ± 0.5% after air mixing for 5 seconds by sequentially injecting specific gravity = 2.68) Vinyl copolymer (EX-1) synthesized by Takemoto Yushi Co., Ltd. under the trade name Chupol HP-11 (hereinafter referred to as HP-11) 0.6 to 0.8% of ordinary portland cement, in the test category 2 0.1% to 0.3% of a 20% aqueous solution of (EX-9), (CE-1) and (CE-2) to ordinary Portland cement, and an AE agent (trade name AE-300 manufactured by Takemoto Yushi Co., Ltd.) To ordinary portland cement 0.0 5%, so as to be 0.001% antifoam agent (Takemoto Yushi Co., Ltd. trade name AFK-2) with respect to ordinary portland cement, was charged with Mixing water, mixed for 90 seconds mixing. Table 2 summarizes the unit amounts and the like of the thus prepared concrete.

Evaluation The slump flow, the air content, the compressive strength after 24 hours, and the bleeding rate of each concrete which had been allowed to stand were measured as follows, at intervals of 30 minutes immediately after mixing, and the results are summarized in Table 3.

Slump flow: Measured according to JIS-A1150 immediately after mixing and at intervals of 30 minutes for each concrete that was allowed to stand.
Air content: Immediately after mixing and at intervals of 30 minutes, the concrete which was allowed to stand was measured according to JIS-A1128.
Compressive strength: In accordance with JIS-A1108, the sample size was 100 mm in diameter × 200 mm in height, and was measured at a material age of 24 hours.
Bleeding rate: Measured in accordance with JIS-A1123.

In Table 3,
Addition ratio of HP-11 (%):% by mass of ordinary Portland cement in the presence of HP-11
Addition ratio (%) of vinyl copolymer:% by mass relative to ordinary portland cement of 20% aqueous liquid such as vinyl copolymer synthesized in test division 2

Also from the results of Table 3 corresponding to Tables 1 and 2, according to the dispersion holding agent of the present invention, the fluidity of the hydraulic composition can be held for a long time without causing curing delay.

Claims (7)

A dispersion holding agent for a hydraulic composition comprising a vinyl copolymer obtained from a monomer A represented by the following chemical formula 1 and a monomer B represented by the following chemical formula 2.

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

(In chemical 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)

(In chemical formula 4,
AO: an oxyalkylene group having 2 to 4 carbon atoms m: an integer of 1 to 10 R ³ : an alkylene group which may have a hetero atom, an aromatic ring group or an unsaturated hydrocarbon group)

(In chemical formula 5,
s: integer from 0 to 4 t: 0 or 1
AO: an oxyalkylene group having a carbon number of 2 to 4 n: an integer of 0 to 300 R ⁴ : a hydrogen atom, an alkyl group having a carbon number of 1 to 22 or an aliphatic acyl group having a carbon number of 1 to 22 When R ⁴ is an alkyl group having 1 to 22 carbon atoms or an aliphatic acyl group having 1 to 22 carbon atoms)) Containing a vinyl copolymer obtained from the monomer A according to claim 1, the monomer B according to claim 1, and another monomer C copolymerizable with these monomers Dispersion retention agent for hydraulic composition characterized by the above. The dispersion holding agent for a hydraulic composition according to claim 1 or 2, wherein R ^{3 in the} chemical formula 4 is an organic group represented by the following chemical formula 6.

(In chemical formula 6,
R ⁵ : an alkylene group having 1 to 22 carbon atoms which may have a hetero atom, an aromatic ring group or an unsaturated hydrocarbon group u: an integer of 0 to 2 M ³ : hydrogen atom, ammonium group, organic amine group, alkali metal Or 1/2 equivalent of alkaline earth metal) 4. The dispersion holding agent for a hydraulic composition according to any one of claims 1 to 3, wherein R ⁵ in the chemical formula 6 is an alkylene group having 1 to 6 carbon atoms, an aromatic ring group or an unsaturated hydrocarbon group. 5. The dispersion holding agent for a hydraulic composition according to any one of claims 1 to 4, wherein the monomer A is a condensate of hydroxyethyl (meth) acrylate and a 2 to 4 basic carboxylic acid anhydride. The dispersion holding agent for a hydraulic composition according to any one of claims 1 to 5, wherein the vinyl copolymer has a weight average molecular weight of 8,000 to 200,000. A vinyl copolymer having 1 to 99% by mole of a constitutional unit derived from monomer A and 1 to 99% by mole (totally 100 mole%) of constitutional units derived from monomer B in all constitutional units The dispersion holding agent for a hydraulic composition according to any one of claims 1 to 6, which is