KR20210013719A - Defoamers for hydraulic compositions, additives for hydraulic compositions, and hydraulic compositions - Google Patents

Abstract

In the polyoxyalkylene-based compound represented by the following general formula (1), the antifoaming agent for hydraulic compositions,
First condition: 0.02≤n/(n+m)<0.16, on the other hand,
Second condition: The antifoaming agent for hydraulic compositions satisfying the relationship of 6≤n+m≤100.
RO-[(EO)n/(AO)m]-H...(1)
(However, R represents an alkyl group or alkenyl group having 8 to 30 carbon atoms, and represents either a linear or branched structure. EO represents an oxyethylene group, and AO represents an oxyalkylene group having 3 to 18 carbon atoms. n and m each represent the average number of added moles, and n is 1 or more and m is 1 or more. In addition, [(EO)n/(AO)m] means n moles of EO and m moles of AO It indicates block addition or random addition.)

Description

Defoamers for hydraulic compositions, additives for hydraulic compositions, and hydraulic compositions

The present invention relates to a defoaming agent for a hydraulic composition, an additive for a hydraulic composition, and to a hydraulic composition, and more particularly, a defoaming agent for a hydraulic composition exhibiting high defoaming performance at low temperatures, for a hydraulic composition including the defoaming agent for the hydraulic composition. It relates to a hydraulic composition comprising an additive, and an antifoaming agent for the hydraulic composition.

Conventionally, a hydraulic composition is obtained by kneading a hydraulic binder and various materials such as water, filling a mold, curing, and then demolding the mold to obtain a cured product. In particular, a concrete composition, which is a kind of hydraulic composition, is prepared by mixing and kneading various materials such as cement, water, aggregate, and dispersant, pouring it into a previously prepared formwork, pouring it, and curing it for a predetermined time. Such a concrete composition has excellent properties such as strength and durability, and is widely used in various buildings and construction structures by taking advantage of the above properties.

Here, in the concrete composition, in order to improve air entrainment and fluidity at the time of kneading in which various materials are kneaded, additives (additives for hydraulic compositions) are usually added. By using such an additive, even when water-reducing the concrete composition is performed, good dispersibility can be maintained. In addition, the handling properties (workability) in kneading and construction can be made good. Therefore, it is possible to construct a concrete composition having excellent stability over time and workability while improving durability and strength of the concrete composition.

In particular, in recent years, it is known to use a polycarboxylic acid-based dispersant as a dispersant capable of uniformly mixing and kneading by increasing the dispersibility of various materials of the hydraulic composition in an additive for hydraulic compositions added to the hydraulic composition. By using a polycarboxylic acid-based dispersant, the sensitivity of the hydraulic composition can be improved. On the other hand, by using a polycarboxylic acid-based dispersant, the air entrainment property can be improved, but the bubble diameter of the bubbles generated at the time of kneading becomes large, which sometimes affects the construction work. In order to solve such inconvenience, in order to generate fine and high-quality air bubbles, and to improve freezing solubility, a so-called AE agent (Air Entraining agent) is used in combination.

In this case, when the polycarboxylic acid-based dispersant and the AE agent are used in combination, a defoaming agent (a defoaming agent for hydraulic compositions) is generally used for the purpose of removing a large number of bubbles generated by the AE agent or the like. For example, a concrete composition comprising a polyoxyalkylene-based compound, cement, water, fine aggregate, and coarse aggregate as essential components is known (see Patent Document 1). In the concrete composition, the polyoxyalkylene-based compound is "0.15<u/(u+v)" as the total number of added moles u of oxyethylene groups in the oxyalkylene group and the total number of added moles of oxyalkylene groups having 3 or more carbon atoms v. It satisfies the relationship of 0.9" and further has at least one aliphatic hydrocarbon group having 5 or more consecutive carbon atoms in the molecule. This has the advantage of suppressing an increase in the amount of air due to an extension of the kneading time and stably maintaining the amount of air entrained. As a result, it becomes possible to provide a high-quality concrete composition excellent in durability and strength.

In other words, conventionally, it was thought that high hydrophobicity is good as a defoaming agent in a concrete composition, but by improving the hydrophilicity of the polyoxyalkylene-based compound due to the oxyethylene group, it effectively suppresses the generation of air bubbles caused by AE agents, It is possible to suppress an increase in the amount of air due to an extension of time. As a result, there is no increase in the amount of air, and the amount of air entrainment can be stabilized.

Patent Document 1 JP 2003-226565 A

On the other hand, in the case of a general polyoxyalkylene-based compound disclosed in Patent Document 1 or the like, there is a possibility of causing the problems described below. Specifically, the polyoxyalkylene compound used as the antifoaming agent for hydraulic compositions has a problem in that the effect of the antifoaming agent decreases or the antifoaming effect disappears in the hydraulic composition at a low temperature. That is, there is a problem that air bubbles cannot be suppressed even when the amount of the antifoam agent is increased or the amount of the antifoam agent is increased at low temperature. In this case, as the amount of the antifoaming agent is increased, the production cost of the hydraulic composition is increased, or air bubbles cannot be suppressed, making it difficult to obtain a hydraulic composition having excellent durability and strength.

In the case of the polyoxyalkylene-based compound shown in Patent Document 1, generation of air bubbles caused by an AE agent or the like could be effectively suppressed. However, the polyoxyalkylene-based compound may not exhibit sufficient defoaming performance at low temperatures. In particular, when the temperature after kneading is less than 10° C., the defoaming performance is rapidly lowered, and even when the amount of the antifoaming agent is increased, it becomes difficult to suppress air bubbles, and thus it has been difficult to obtain a hydraulic composition having excellent durability and strength.

In order to solve the above problems, the applicant of the present application, as a result of repeated intensive research, in the polyoxyalkylene-based compound used as an antifoaming agent for hydraulic compositions, the molar ratio of the oxyethylene group constituting the polyoxyalkylene-based compound, and poly By optimizing the total number of moles of the oxyethylene group constituting the oxyalkylene compound and the oxyethylene group having 3 to 18 carbon atoms, the antifoaming agent for hydraulic compositions, and the antifoaming agent for hydraulic compositions, exhibiting high defoaming performance at low temperatures. Invention related to hydraulic compositions including additives for hydraulic compositions, including antifoaming agents for hydraulic compositions thereof, and the like were found.

Accordingly, the present invention is to provide an antifoaming agent for hydraulic compositions, an additive for hydraulic compositions, and a hydraulic composition capable of exhibiting particularly high antifoaming performance at low temperatures in view of the above circumstances.

According to the present invention, there are provided an antifoaming agent for a hydraulic composition, an additive for a hydraulic composition, and a hydraulic composition described below.

[1] It is a polyoxyalkylene-based compound represented by the following general formula (1),

First condition: 0.02≤n/(n+m)<0.16, on the other hand,

Second condition: Defoamer for hydraulic compositions satisfying the relationship of 6≤n+m≤100.

RO-[(EO)n/(AO)m]-H...(1)

(However, R represents an alkyl group or alkenyl group having 8 to 30 carbon atoms, and represents either a linear or branched structure. EO represents an oxyethylene group, and AO represents an oxyalkylene group having 3 to 18 carbon atoms. n and m each represent the average number of added moles, while n is 1 or more and m is 1 or more. [(EO)n/(AO)m] means n moles of EO and m moles of AO It indicates block addition or random addition.)

[2] The antifoaming agent for hydraulic compositions according to [1], wherein the kneading temperature, which is the temperature immediately after kneading of the hydraulic composition, is 3°C or more and less than 15°C.

[3] The antifoaming agent for hydraulic compositions described in [1] or [2], wherein R in the general formula (1) is an alkyl group or alkenyl group having 14 to 22 carbon atoms.

[4] The antifoaming agent for hydraulic compositions according to any one of [1] to [3], wherein AO in the general formula (1) is an oxypropylene group.

[5] The antifoaming agent for hydraulic compositions according to any one of [1] to [4], wherein the second condition further satisfies the condition of 6≦n+m≦50.

[6] An additive for hydraulic compositions comprising the defoaming agent for hydraulic compositions according to any one of [1] to [5], a polycarboxylic acid-based dispersant, and water as essential components.

[7] A hydraulic composition comprising the antifoaming agent for hydraulic compositions according to any one of [1] to [5], a polycarboxylic acid-based dispersant, and cement as essential components.

[8] A hydraulic composition comprising as an essential component an aggregate containing the antifoaming agent for hydraulic compositions according to any one of [1] to [5], a polycarboxylic acid-based dispersant, cement, and a fine bone agent and/or a coarse aggregate.

According to the antifoaming agent for hydraulic compositions of the present invention, it exhibits high antifoaming performance at a low temperature, and on the other hand, the difference between room temperature and low temperature can be made small. In addition, by using an additive for a hydraulic composition including the antifoaming agent for the hydraulic composition or the antifoaming agent for the hydraulic composition, a hydraulic composition having excellent durability and strength can be created.

Hereinafter, an embodiment of the antifoaming agent for a hydraulic composition, an additive for a hydraulic composition, and a hydraulic composition of the present invention will be described. Here, the antifoaming agent for a hydraulic composition of the present invention (hereinafter, simply referred to as an ``antifoaming agent''), the additive for the hydraulic composition, and the hydraulic composition are not limited to the following embodiments, unless departing from the scope of the present invention, Changes, corrections, and improvements can be added.

1. Antifoam (antifoam for hydraulic compositions)

The antifoaming agent of one embodiment of the present invention is a polyoxyalkylene-based compound represented by the following general formula (1),

First condition: 0.02≤n/(n+m)<0.16, on the other hand,

Second condition: The relationship of 6≤n+m≤100 is satisfied.

RO-[(EO)n/(AO)m]-H...(1)

In the general formula (1), "R" represents an alkyl group or alkenyl group having 8 to 30 carbon atoms, and represents either a linear or branched structure. Further, "EO" represents an oxyethylene group, and "AO" represents an oxyalkylene group having 3 to 18 carbon atoms. On the other hand, n and m each represent an average number of added moles, while n is 1 or more and m is 1 or more. In addition, [(EO)n/(AO)m] indicates that n moles of EO and m moles of AO are added by block or at random.

That is, the antifoaming agent of the present embodiment is a polyoxyalkylene-based compound represented by the general formula (1), and is constituted by block addition or random addition of an oxyethylene group (EO) and an oxyalkylene group (AO). , The average added mole number of EO and AO satisfies all of the first and second conditions shown above, and is configured.

In addition, the antifoaming agent of the present embodiment can be used in a range of 0°C or more and less than 18°C, more preferably 3°C or more and less than 15°C in a "kneading temperature", which is the temperature immediately after kneading of the hydraulic composition. That is, the defoaming performance at low temperature is excellent. Here, in this specification, "low temperature (hour)" is defined as a range of 0°C or more and less than 18°C.

Here, R in the general formula (1) is an alkyl group or alkenyl group having 8 to 30 carbon atoms, more preferably 14 to 22 carbon atoms. In particular, R may use a residue other than a hydroxy group from the alcohol, and the alcohol that can be used is not particularly limited, and for example, octanol, nonaol, decanol, undecanol, dodecanol, tridecanol, tetra Decanol, pentadecanol, hexadecanol, heptadecanol, octadecanol, nonadecanol, eicosanol, heneicosanol, docosanol, tricosanol, tetracosanol, pentacosanol, hexacosanol, hep Straight-chain alkanols such as tacosanol, octacosanol, nonacosanol and triacontanol; 2-ethylhexanol, 2-propylheptanol, 2-butyloctanol, 1-methylheptadecanol, 2-hexyloctanol, 2 -Branched alkanols such as hexyldecanol, isodecanol, isotridecanol, 3,5,5-trimethylhexanol; octenol, nonenol, decenol, undecenol, dodecenol, tridecenol, tetrade Senol, pentadecenol, hexadecenol, pentadecenol, hexadecenol, heptadecenol, octadecenol, nonadesenol, eisenol, docosenol, tetracosenol, pentacosenol, hexacosenol, heptaco Straight-chain alkenols such as senol, octacosenol, nonacosenol, and triaconsenol; branched alkenols such as 2-ethylhexenol, 1-methylheptadecenol, isotridecenol, and isooctadecenol. have. Further, as the alcohol used as R, only one of the above-described alcohols may be used, or two or more alcohols may be used in combination.

In addition, specific examples of usable alcohols are high-grade alcohols derived from natural fats and oils, Calcohol series (Kao), Conol series (New Japan Chemicals), Fine Oxochol series (Nissan Chemicals), Neodol series (Shell Chemicals), SAFOL. Series (SASOL), EXXAL series (Exon Mobile), and the like.

On the other hand, AO (oxyalkylene group) in General Formula (1) represents an oxyalkylene group having 3 to 18 carbon atoms. As a C3-C18 oxyalkylene group, an oxypropylene group, an oxybutylene group, an oxyhexylene group, an oxyoctylene group, an oxystyrene group, etc. can be shown, for example. In particular, it is very suitable to make AO an oxypropylene group. Thereby, higher defoaming performance can be exhibited at low temperature.

In addition, in the antifoaming agent of the present embodiment, the second condition in General Formula (1) may satisfy the condition of 6≦n+m≦50. That is, the range of the above-described second condition may be narrower. By further limiting the range of the second condition, an excellent antifoaming agent exhibiting a higher antifoaming performance at low temperature can be obtained.

2. Additives for hydraulic compositions, and hydraulic compositions

By using the antifoaming agent shown above, an additive for a hydraulic composition and a hydraulic composition can be obtained. Here, the additive for hydraulic compositions contains a polycarboxylic acid-based dispersant and water as essential components together with the antifoaming agent. Thereby, it is possible to obtain an additive for hydraulic compositions capable of exhibiting high defoaming performance even at low temperatures. On the other hand, the hydraulic composition further contains cement as an essential component in the related additive for hydraulic compositions, or further contains cement and aggregate as essential components. In addition, since the additive for hydraulic compositions or water contained in the hydraulic composition is well known, a detailed description is omitted here. In addition, as the aggregate contained in the hydraulic composition, fine aggregates such as sand, and/or coarse aggregates such as gravel, crushed stone, crushed slug, and recycled aggregate can be suitably used. In addition, since the details of the polycarboxylic acid-based dispersant will be described later, explanation is omitted here.

3. Method for producing an antifoaming agent (polyoxyalkylene compound)

The production method for producing the antifoaming agent (polyoxyalkylene compound) of the present embodiment is not particularly limited, and can be produced by a known production method. For example, a polyoxyalkylene-based compound can be obtained by adding an alkylene oxide to an alcohol. Here, when the alkylene oxide is added, a catalyst may be used. As the catalyst, an alkali metal and alkaline earth metal, hydroxides thereof, alkali catalysts such as Alkorat, Lewis acid catalysts, and complex metal catalysts are used. It is possible, and preferably an alkali catalyst can be used.

Examples of alkali catalysts that can be used include sodium, potassium, sodium potassium amalgam, sodium hydroxide, potassium hydroxide, sodium hydride, sodium methoxide, potassium methoxide, sodium ethoxide, potassium ethoxide, potassium butoxide, etc. And sodium hydroxide, potassium hydroxide, sodium methoxide, potassium methoxide, and potassium butoxide.

On the other hand, as a Lewis acid catalyst that can be used, for example, tin tetrachloride, boron trifluoride, boron trifluoride diethyl ether complex, boron trifluoride di n-butyl ether complex, boron trifluoride tetrahydrofuran complex, boron trifluoride And boron trifluoride compounds such as a phenol complex and a boron trifluoride acetic acid complex.

These catalysts can be neutralized and removed after the addition reaction, and on the other hand, they may be contained as they are. In the case of neutralizing the catalyst, it can be carried out by a known method. For example, if the catalyst is an alkaline catalyst, as a neutralizing agent, acids such as hydrochloric acid, sulfuric acid, methane sulfonic acid, phosphoric acid, acetic acid, lactic acid, citric acid, and succinic acid, silicates such as aluminum silicate and magnesium silicate, activated clay, acid clay, Adsorbents such as silica gel and acidic ion exchange resin can be used.

In addition, specifically explaining neutralization, as commercially available adsorbents, for example, KYOWAAD 600, 700 (each brand name: Kyowa Chemical Industries), MIZUKALIFE P-1, P-1S, P-1G, F-1G ( Each brand name: Mizusawa Industrial Chemicals), TOMITA-AD600, 700 (each brand name: Tomita Pharmaceutical) silicate; DIAION (brand name: Mitsubishi Chemical), AMBERLYST, AMBERLITE, DOWE X (each brand name: Dow Chemical) Ion exchange resins, such as, etc. can be used. These neutralizing agents may be used alone or in combination of two or more.

The neutralized salt (neutralized product) produced by neutralization of the catalyst can be solid-liquid again. As a method of solid-liquid separation of the neutralized salt, known methods such as filtration or centrifugation can be used. Here, for solid-liquid separation by filtration, for example, a filter paper, a filter cloth, a cartridge filter, a two-layer filter of cellulose and polyester, a metal mesh filter, a metal sintered filter, etc. are used, and the temperature is 20 under reduced pressure or pressure. It can be carried out under conditions of -140°C. On the other hand, solid-liquid separation by centrifugation can be carried out using, for example, a centrifuge such as a decanter or a centrifugal clarifier. Further, if necessary, about 1 to 30 parts by mass of water may be added to 100 parts by mass of the solution before solid-liquid separation. As the solid-liquid separation, particularly when filtration is carried out, the use of a filter aid is more suitable because the filtration speed is improved.

The filter aid used for filtration is not particularly limited, and for example, Celite, High Flow Supercell, Celpure series (trade name: Advanced Minerals Corporation), Silika#645, Silika#600H, Silika#600S, Silika# Diatomaceous earth such as 300S, Silika#100F (trade name: Chuo Silika), Dicalite (trade name: Grefco); Pearlite such as ROKAHELP (brand name: Mitsui Mining & Smelting), Topco (brand name: Showa Chemical Industries); KC FLOCK Cellulose filter aids, such as (brand name: Nippon Paper) and FIBRACEL (Advanced Minerals Corporation); silica gels, such as Sylopute (brand name: Fuji Silysia Chemical), etc. are mentioned. Further, only one type of the above-described filter aid may be used, or two or more types may be used in combination.

In addition, known polycarboxylic acid dispersants can be used. For example, a copolymer composed of a monomer represented by the following general formula (2) and an unsaturated carboxylic acid-based monomer can be mentioned.

R ¹ -OAR ² ...(2)

(However, in the general formula (2), R 1 represents an alkenyl group having 2 to 5 carbon atoms or an unsaturated acyl group having 3 or 4 carbon atoms, and A is one or two or more of an oxyalkylene group having 2 to 4 carbon atoms It is an average added mole number of 1 to 500 (poly) oxyalkylene units, and R ² represents a hydrogen atom, an alkyl group having 1 to 22 carbon atoms, or an aliphatic acyl group having 1 to 22 carbon atoms.)

Examples of the unsaturated carboxylic acid-based monomer include (meth)acrylic acid, crotonic acid, and the like as monocarboxylic acid-based monomers, and salts thereof, and maleic acid, itaconic acid, fumaric acid, and the like, and salts thereof as dicarboxylic acid-based monomers. Among them, (meth)acrylic acid, maleic acid, and salts thereof are preferred. The salt is not particularly limited, and examples thereof include alkali metal salts such as sodium and potassium, alkaline earth metal salts such as magnesium and calcium, metal salts with aluminum or iron, ammonium salts, and amine salts.

In addition to the above-described monomers and unsaturated carboxylic acid-based monomers, the copolymer can be obtained by reacting any appropriate monomer (third monomer). In this case, as the third monomer, for example, (meth)arylsulfonic acid and its salt, (meth)acrylamide, acrylonitrile, (meth)acrylic acid ester, and the like can be used.

Further, the polycarboxylic acid-based dispersant can be prepared by a known method. In addition, the copolymer can be produced by a known method. For example, a copolymer can be synthesized by radical polymerization and obtained by mixing (heating) the above monomer, unsaturated carboxylic acid monomer, and a third monomer and a radical initiator. Examples of the radical initiator to be used include persulfates such as potassium persulfate and ammonium persulfate, hydrogen peroxide, 2,2-azobis(2-amidinopropane) dihydrochloride, azobisisobutyronitrile, and the like. These can also be used as a Redox initiator in combination with a reducing substance such as sulfite or L-ascorbic acid, or an amine. In addition, chain transfer agents such as 2-mercaptoethanol, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thioglycolic acid, mercaptoethanol, and thioglycerin may also be used in order to bring the mass average molecular weight of the obtained copolymer into a desired range. have. In addition, for polymerization, water or an organic solvent may be used as the solvent, or no solvent may be used.

(Example)

Hereinafter, the antifoaming agent of the present invention and a hydraulic composition containing the antifoaming agent will be described based on the following examples. In addition, the defoaming agent and hydraulic composition of the present invention are not limited to the following examples. In addition, since the conditions of a specific method (addition reaction, etc.) for producing the antifoaming agent have already been described, detailed descriptions are omitted here.

1. Synthesis of antifoaming agent (polyoxyalkylene compound)

First, alcohol was used as R in General Formula (1) to synthesize a defoaming agent (polyoxyalkylene compound). First, 128.3 g of alcohol A1 ("UNJECOL 85AN (brand name: New Japan Chemical)") and 0.9 g of potassium hydroxide were put into a pressure vessel equipped with a stirrer, a pressure gauge, and a thermometer. The melting point of alcohol A1 ("UNJECOL 85AN") is about 11°C, and is in a liquid state at room temperature around 20°C.

In this state, after performing the dehydration treatment, 87.1 g of ethylene oxide was press-in over 1 hour at a gauge pressure of 0.4 MPa while maintaining the reaction system in the pressure vessel at 110±5° C., and then aged for 2 hours. Further, while maintaining the reaction system at 135±5° C., 706.5 g of propylene oxide was press-in over 5 hours at a gauge pressure of 0.4 MPa, and then aged for 2 hours to complete the reaction.

Thereafter, neutralization treatment was performed using "KYOWAAD 600 (trade name: Kyowa Chemical Industry)" as an adsorbent, followed by filtering by filtration to obtain a purified product. From the analysis results of NMR and gel permeation chromatography (mass average molecular weight in terms of polystyrene), the purified product was an antifoaming agent af-1 obtained by sequentially adding 4.1 mol of ethylene oxide and 2.2 mol of propylene oxide to 1.0 mol of lauryl alcohol. (Polyoxyalkylene compound). Measurement conditions for NMR and gel permeation chromatography are shown below.

<Measurement conditions>

(1) NMR

Device: Varian Mercury 300 (300 MHz)

Nuclides: 1H, 13C

Solvent: CDCl3

(2) Gel permeation chromatography

Apparatus: HLC-8120 GPC (Tosoh)

Column: TSK gel Super H4000+TSK gel Super H3000+TSK gel Super H2000 (Toso)

Detector: Differential Refractometer (RI)

Eluent: Tetrahydrofuran

Flow: 0.5mL/min

Column temperature: 40℃

Sample concentration: Eluent solution with sample concentration of 0.5% by mass

Standard substance: Polystyrene (Tosoh)

The type of alcohol A1 to A4 to be used, the alkylene oxide (oxypropylene group), the order of addition in the addition reaction, the addition amount, etc. are changed, and according to the conditions of Table 1 shown below, the antifoaming agent af-1 The same treatment as the synthesis was carried out, and various antifoaming agents af-2 to af-6, af-e1 and af-e2 were synthesized. Table 2 shows the aggregated details of the detailed properties, properties, and states (straight chain/branched chain, saturated/unsaturated, and carbon number steps) of alcohols A1 to A4 used in the synthesis of the antifoaming agent.

In Table 1, the antifoam agents af-1 to af-6 and the antifoam agent of the present invention were synthesized by satisfying both the first and second conditions. In contrast, the antifoaming agents af-e1 and af-e2 were synthesized by deviating from the first condition.

2. Synthesis of copolymers used in polycarboxylic acid-based dispersants and preparation of dispersants

(1) Preparation Example 1 (Preparation of dispersant SP-1)

Ion-exchanged water 140.1 g, α-methacryloyl-ω-methoxy-poly (n=9) oxyethylene 163.0 g, methacrylic acid 28.8 g, 3-mercaptopropionic acid 3.8 g, 30% sodium hydroxide aqueous solution 9.9 g Was put into a reaction vessel equipped with a thermometer, a stirrer, a dropping lot, and a nitrogen introduction tube, and after uniformly dissolving while stirring, the atmosphere was replaced with nitrogen to set the temperature of the reaction system to 60° C. in a hot water bath. Subsequently, 63.9 g of an aqueous 3.0% sodium persulfate solution was added to initiate the polymerization reaction. After 2 hours, 28.8 g of a 3.0% sodium persulfate aqueous solution was added, and the mixture was maintained at 60°C for 2 hours to complete the polymerization reaction. Thereafter, a 30% aqueous sodium hydroxide solution was added to adjust the pH to 8, and a dispersant whose concentration was adjusted to 20% in ion-exchanged water was used as (SP-1).

(2) Preparation Example 2 (Preparation of dispersant SP-2)

209.2 g of ion-exchanged water, 181.9 g of α-methacryloyl-ω-methoxy-poly(n=45)oxyethylene, 15.8 g of methacrylic acid, 2.0 g of 3-mercaptopropionic acid were added to the thermometer, stirrer, dropping lot, After placing in a reaction vessel equipped with a nitrogen introduction tube and uniformly dissolving while stirring, the atmosphere was replaced with nitrogen to set the temperature of the reaction system to 60°C in a hot water bath. Then, 27.7 g of 1.0% aqueous hydrogen peroxide solution was added dropwise over 2.5 hours. Then, 7.1 g of 1.0% hydrogen peroxide aqueous solution was dripped over 3.5 hours, and the polymerization reaction was terminated. Thereafter, a 30% aqueous sodium hydroxide solution was added to adjust the pH to 9 to obtain a dispersant (SP-2) whose concentration was adjusted to 20% in ion-exchanged water.

(3) Preparation Example 3 (Preparation of dispersant SP-3)

82.6 g of ion-exchanged water, 175.7 g of α-methryl-ω-hydroxy-poly(n=113) oxyethylene were placed in a reaction vessel equipped with a thermometer, stirrer, dropping lot, and nitrogen inlet tube, and uniformly dissolved while stirring. Thereafter, the atmosphere was replaced with nitrogen, and the temperature of the reaction system was set to 60°C in a hot water bath. Then, 9.8 g of 10.0% hydrogen peroxide aqueous solution was added dropwise over 3.0 hours, and at the same time, an aqueous solution in which 11.7 g of acrylic acid and 7.8 g of hydroxyethyl acrylate were dissolved in 97.6 g of ion-exchanged water was added dropwise over 3.0 hours, followed by ion exchange. An aqueous solution in which 0.8 g of 3-mercaptopropionic acid and 1.0 g of ascorbic acid were dissolved in 7.0 g was added dropwise over 4.0 hours. After that, the temperature was maintained at 60°C for 0.5 hours to complete the polymerization reaction. Thereafter, a 30% aqueous sodium hydroxide solution was added to adjust the pH to 5 to obtain a dispersion (SP-3) in which the concentration was adjusted to 20% in ion-exchanged water.

The mass average molecular weight of the dispersant was measured by gel permeation chromatography in accordance with the measurement conditions shown below.

<Measurement conditions>

Device: Shodex GPC-101 (Showa Major)

Column: OHpak SB-806M HQ+SB-806M HQ (Showa Denko)

Detector: Differential Refractometer (RI)

Eluent: 50 mM sodium nitrate aqueous solution

Flow rate: 0.7mL/min

Column temperature: 40℃

Sample concentration: Eluent solution with sample concentration of 0.5% by mass

Standard substance: polyethylene glycol, polyethylene oxide (adirent)

Water was removed from the dispersants SP-1 to SP-3 prepared in each of Preparation Examples 1 to 3, and the solution was adjusted to a concentration of 5% using heavy water, and measurement was performed by NMR at 300 MHz. Thereby, it was confirmed that each monomer was polymerized and became a copolymer. Types and respective masses (%) of each component (component A, component B (component B1, component B2)) used in each of the dispersants SP-1 to SP-3 prepared according to Preparation Examples 1 to 5, and by the above The values of the measured mass average molecular weight and pH of each of the dispersants SP-1 to SP-3 are shown in Table 3 below.

In addition, in the description in Table 3, the following terms represent the following meanings.

L-1: α-methacryloyl-ω-methoxy-poly(n=9)oxyethylene

L-2: α-methacryloyl-ω-methoxy-poly(n=45)oxyethylene

L-3: α-metaryl-ω-hydroxy-poly (n=113) oxyethylene

L-4: Hydroxyethyl acrylate

M-1: Methacrylic acid

M-2: Acrylic acid

3. Effect of antifoaming performance by antifoaming agent

Next, the effect of the antifoaming performance of the synthesized various antifoaming agents af-1 and the like (polyoxyalkylene compound) was confirmed. First, as shown below, the concrete composition was prepared.

(1) Preparation of concrete composition

Each of the ingredients was temperature-adjusted so as to achieve a target kneading temperature. Portland cement (Taiheiyo Cement, Ube Mitsubishi Cement, Sumitomo Osaka Cement. Here, an equal amount of the above three items are mixed, specific gravity = 3.16) and fine aggregate (Oigawa water-based sand, specific gravity = 2.58) and coarse aggregate (crushed stone from Okazaki, specific gravity = 2.66) were added sequentially at the mixing ratio shown in Table 4, respectively, and air kneaded for 10 seconds, after which the slump became 18±2.5 cm, so that the poly(s) shown in Table 3 Carboxylic acid-based dispersants SP-1, SP-2, and "AE-300 (trade name: Takemoto Oil & Fat)" as AE agents, 0.0025 mass% based on cement, antifoaming agents af-1 to af-6 shown in Table 1, Af-e1 and af-e2 were kneaded by adjusting the amount of addition as shown in Table 6 below, and added together with water, followed by kneading for 90 seconds. Here, the antifoaming agent af-1 and the like and the polycarboxylic acid-based dispersant SP-1 are considered as part of the dough. In the same manner, the polycarboxylic acid-based dispersant SP-3 shown in Table 3 and the antifoaming agents af-1 to af-6, af-e1, and af-e2 shown in Table 1 are shown in Table 7 below in the same mixing ratio shown in Table 5. In the kind of street, I kneaded.

(2) Effects of defoaming performance

About the concrete composition immediately after kneading, the "air volume (%)" was measured according to JIS-A1128. The amount of air (%) represents the volume% in the hydraulic composition. In addition, at the same time as the measurement of the air amount (%), "slump (cm)" was measured in accordance with JIS-A1101. In addition, at the same time as the measurement of the air amount (%), the temperature immediately after kneading was measured according to JIS-A1156. The effect of the defoaming performance of the defoaming agent at low temperature was confirmed by the amount of air (%) and the temperature immediately after kneading. The measurement results are shown in Tables 6 and 7 below.

In order to compare the effect of the defoaming performance, the amount of the defoaming agent added was fixed for each formulation. According to this, the defoaming agents af-1 to af-6 satisfying the first and second conditions in the present invention exhibit a good defoaming effect at a low temperature of 5°C or 12°C immediately after kneading. Was confirmed. Particularly, it was found that good defoaming performance was exhibited even when the temperature immediately after kneading was lower than that of 5°C. On the other hand, when the synthesized antifoam agents af-e1 and af-e2 were used for comparison, it was found that the amount of air (%) increased especially when the kneading temperature was low of 5°C (Comparative Examples 1, 2, 4 , 5). In addition, when the kneading temperature is 12°C, the value of the amount of air (%) is slightly improved, but in any case, the defoaming performance is low (Comparative Examples 3 and 6). That is, when the antifoaming agent of the present invention is used as one of the essential components of the hydraulic composition, it has been confirmed that the antifoaming agent exhibits particularly high antifoaming performance at low temperatures.

According to the antifoaming agent for hydraulic compositions of the present invention, it can be used as a defoaming agent when preparing a hydraulic composition. Moreover, according to the additive for hydraulic compositions of this invention, it can be used as an additive when preparing a hydraulic composition. The hydraulic composition of the present invention uses an antifoaming agent capable of exhibiting high antifoaming performance at low temperatures, and can be advantageously used for various types of buildings and construction members of building members.

Claims (8)

[1] In the polyoxyalkylene-based compound represented by the following general formula (1),
First condition: 0.02≤n/(n+m)<0.16, on the other hand,
Second condition: Defoamer for hydraulic compositions satisfying the relationship of 6≤n+m≤100.
RO-[(EO)n/(AO)m]-H...(1)
(However, R represents an alkyl group or alkenyl group having 8 to 30 carbon atoms, and represents either a linear or branched structure. EO represents an oxyethylene group, and AO represents an oxyalkylene group having 3 to 18 carbon atoms. n and m each represent the average number of added moles, while n is 1 or more and m is 1 or more. [(EO)n/(AO)m] means n moles of EO and m moles of AO It indicates block addition or random addition.) The method according to claim 1,
An antifoaming agent for hydraulic compositions that can be used in a range of 3°C or more and less than 15°C, which is a temperature immediately after kneading of the hydraulic composition. The method according to claim 1 or 2,
R in the said general formula (1) is a C14-C22 alkyl group or an alkenyl group, The defoaming agent for hydraulic compositions. The method according to any one of claims 1 to 3,
The antifoaming agent for hydraulic compositions, wherein AO in the general formula (1) is an oxypropylene group. The method according to any one of claims 1 to 4,
The second condition further satisfies the condition of 6≦n+m≦50, the antifoaming agent for hydraulic compositions. The antifoaming agent for hydraulic compositions according to any one of claims 1 to 5, and
A polycarboxylic acid-based dispersant,
An additive for hydraulic compositions containing water as an essential component. The antifoaming agent for hydraulic compositions according to any one of claims 1 to 5, and
A polycarboxylic acid-based dispersant,
A hydraulic composition containing cement as an essential component. The antifoaming agent for hydraulic compositions according to any one of claims 1 to 5, and
Polycarboxylic acid dispersant and cement,
A hydraulic composition comprising as an essential component an aggregate containing fine bone and/or coarse aggregate.