Admixture for hydraulic compositions

Abstract

To provide an admixture for hydraulic compositions that can suppress blackening and excels in storage stability, particularly storage stability during storage at high temperatures.SOLUTION: An admixture for hydraulic compositions comprises: (A) a copolymer comprising a constitutional unit derived from olefin having 6 or more and 14 or less carbon atoms and a constitutional unit derived from one or more kinds of compounds selected from maleic acid and fumaric acid, with a weight average molecular weight of 10,000 or more and 100,000 or less; (B) a predetermined copolymer comprising a compound having a polyalkyleneoxy group and a compound having a carboxylic acid group as constituent monomers; and water, wherein an electric conductivity is 11 ms / cm or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an admixture for a hydraulic composition.

Background Art

[0002] A concrete admixture is a material used to modify the properties of concrete by reacting or combining with cement paste. Many of them are composed of inorganic powders and are widely used to replace cement or impart special functions to concrete. Representative admixtures include blast furnace slag for the purpose of cement replacement, artificial pozzolans (fly ash, silica fume, etc.), etc. Appropriate addition of these is important in concrete production. Generally, blast furnace slag, fly ash, silica fume, and sub-bituminous coal contain black fine powder, etc.

[0003] However, due to the increasing use of silica fume, fly ash, blast furnace slag, etc. in recent years, the mixing of incineration ash into cement (utilization of industrial waste), the use of aggregates and admixtures containing sub-bituminous coal, and the high fluidization of concrete for the purpose of improving workability and environmental performance, a phenomenon occurs where black patches appear on the surface of the concrete after hardening or the whole becomes black. For example, in the case of concrete using a polycarboxylic acid-based polymer as a water reducing agent, it is remarkable, and an effective improvement measure is desired. Patent Document 1 discloses a hydraulic admixture containing a specific olefin-maleic acid copolymer (I) and one or more copolymers (II) selected from the group consisting of specific copolymers (A), (B), and (C). Patent Document 2 discloses a concrete admixture containing an olefin-maleic acid copolymer (1) having a structural unit composed of a divalent hydrocarbon having 6 to 14 carbon atoms and a weight average molecular weight of 1,000 to 20,000, and a polycarboxylic acid-based polymer (2) other than (1). Patent Document 3 discloses an inhibitor for suppressing the deposition of black substances on the surface of a hardened concrete body containing a copolymer of a monoolefin having 6 to 10 carbon atoms and maleic acid or a salt thereof; and a method for improving the appearance of the surface of a hardened concrete body in which 0.0001 to 0.1 part by mass of a copolymer of a monoolefin having 6 to 10 carbon atoms and maleic acid or a salt thereof is added in terms of solid content based on 100 parts by weight of cement.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] It has been desired to further improve the storage stability of admixtures for hydraulic compositions during high-temperature storage. The present invention provides an admixture for a hydraulic composition capable of suppressing blackening, and a novel admixture for a hydraulic composition excellent in storage stability, particularly storage stability during high-temperature storage.

Means for Solving the Problems

[0006] The present invention relates to an admixture for a hydraulic composition containing (A) a copolymer having a structural unit (a1) derived from an olefin having 6 or more and 14 or less carbon atoms and a structural unit (a2) derived from one or more compounds selected from maleic acid and fumaric acid, and having a weight average molecular weight of 10,000 or more and 100,000 or less [hereinafter referred to as component (A)], (B) a copolymer having a structural unit derived from a compound (b1) represented by the following general formula (b1) and a structural unit derived from a compound (b2) represented by the following general formula (b2) [hereinafter referred to as component (B)], and water, and having an electric conductivity of 11 ms / cm or less.

[0007]

Chem.

[0008] 〔In the formula, R 4a , 1 , , 1 , , 5a , , 1 , r , 6a , 1 , , 1 , r , r , and R 2b : may be the same or different, and is a hydrogen atom or a methyl group R 3b : is a hydrogen atom or -(CO) q O(AO) n X X: an alkyl group having 1 to 4 carbon atoms or a hydrogen atom AO: a group selected from an ethyleneoxy group and a propyleneoxy group n: the average number of moles of addition of AO, and is a number of 1 or more and 300 or less p: a number of 0 or more and 2 or less q: a number of 0 or 1 is shown.〕

[0009]

Chem.

[0010] 〔In the formula, R 4a and R 5a and R 6a : may be the same or different, and is a hydrogen atom, a methyl group or (CH2) r COOM 1 where (CH2) r COOM 1 may form an anhydride with COOM or another (CH2) r COOM 1 and in that case, M and M 1 do not exist. M and M 1 : may be the same or different, and is a hydrogen atom, an alkali metal, an alkaline earth metal (1 / 2 atom), an ammonium group, an alkylammonium group or a substituted alkylammonium group r: a number of 0 or more and 2 or less is shown.〕

Advantages of the Invention

[0011] According to the present invention, it is possible to provide a novel admixture for hydraulic compositions that can suppress discoloration and has excellent storage stability, particularly storage stability when stored at high temperatures. [Modes for carrying out the invention]

[0012] The inventors have found that by reducing the electrical conductivity of an admixture for hydraulic compositions to 11 ms / cm or less, the storage stability of the admixture, for example, its storage stability at temperatures above 40°C, is improved. The reason for this improvement in storage stability is not entirely clear, but it is thought to be as follows. It is believed that when the electrical conductivity of an admixture for aqueous compositions increases (i.e., the amount of ions in the admixture increases), the interaction of ions with water makes it easier for polymers to separate. Therefore, by keeping the electrical conductivity of the admixture within a predetermined range, the interaction of ions with water is reduced, and the storage stability of the admixture, especially its storage stability at high temperatures, is improved. However, the present invention is not limited to this mechanism.

[0013] The admixture for hydraulic compositions of the present invention comprises component (A), component (B), and water, and has an electrical conductivity of 11 ms / cm or less.

[0014] Component (A) is a copolymer having a constituent unit (a1) derived from an olefin [hereinafter referred to as constituent unit (a1)] and a constituent unit (a2) derived from one or more compounds selected from maleic acid and fumaric acid [hereinafter referred to as constituent unit (a2)]. Examples of constituent monomers constituting component (A) include olefins and maleic acid, maleic anhydride, maleate, fumaric acid, and fumaate. Examples of the salts include monovalent metal salts such as sodium salts and potassium salts, divalent metal salts such as magnesium salts, and organic amine salts such as ammonium salts, monoethanolamine salts, diethanolamine salts, and triethanolamine salts, with sodium salts being preferred. Component (A) is preferably a copolymer having a structural unit (a1-1) and a structural unit (a2) derived from a chain-like olefin. From the viewpoint of not inhibiting the dispersion of carbons and cement, the number of carbon atoms in the olefin is 6 or more, preferably 8 or more, and 14 or less, preferably 12 or less, and more preferably 10 or less. Component (A) is preferably a copolymer having a structural unit (a) represented by the following general formula (a). Component (A) can be used by one or more types.

[0015] [ka]

[0016] [During the ceremony, R: A divalent hydrocarbon group with 6 to 14 carbon atoms. X: Hydrogen atom, monovalent metal, divalent metal, ammonium group, organoammonium group That is the case.

[0017] Component (A) can be an acidic or neutralized salt, and the degree of neutralization can be arbitrarily selected. Therefore, X in constituent unit (a) is a hydrogen atom, a monovalent metal, a divalent metal, an ammonium group, or an organic ammonium group. The organic ammonium group is preferably an alkyl or hydroxyalkyl (2 to 6 carbon atoms) substituted ammonium group. Examples of salts include monovalent metal salts, such as alkali metal salts such as sodium and potassium; divalent metal salts, such as alkaline earth metal salts such as calcium and magnesium; ammonium salts; and organic ammonium salts, such as alkanol (2 to 6 carbon atoms) ammonium salts, but alkali metal salts are preferred.

[0018] Component (A) can be, for example, a copolymer of diisobutylene and at least one monomer selected from the group consisting of maleic anhydride, maleic acid, and fumaric acid. However, from the viewpoint of obtaining a dispersant with high blackening suppression ability, a copolymer of diisobutylene and maleic anhydride is preferred.

[0019] Furthermore, the weight-average molecular weight of component (A) (calculated by gel permeation chromatography / polystyrene sulfonic acid) is preferably 10,000 or more, more preferably 15,000 or more, even more preferably 20,000 or more, and preferably 100,000 or less, more preferably 80,000 or less, and even more preferably 30,000 or less. Component (A) can be produced, for example, by the method described in Japanese Patent Publication No. 55-40797.

[0020] [(A) Measurement of weight-average molecular weight] The weight-average molecular weight of component (A) was measured by GPC (gel permeation chromatography) under the following conditions. The weight-average molecular weight was calculated based on a pre-prepared calibration curve. The following standard samples were used to prepare the calibration curve. Measuring device: HLC-8120GPC (manufactured by Tosoh Corporation) Columns: TSK α-M + α-M (both manufactured by Tosoh Corporation) Column temperature: 40℃ Detector: RI Eluent: N,N-dimethylformamide solution with H3PO4 (60 mmol / L) and LiBr (50 mmol / L) added. Flow rate: 1.0mL / min Sample concentration: 0.1% by mass (solids) Sample injection volume: 0.1 mL Standard sample: Polystyrene manufactured by Tosoh Corporation, 5.26 × 10 2 , 1.02 × 10 5 , 8.42×10 6 Nishio Kogyo Co., Ltd. Polystyrene 4.0 x 10 3 , 3.0×10 4 , 9.0×10 5 (The numbers represent molecular weights)

[0021] (A) The molar ratio of constituent unit (a1) to constituent unit (a2) constituting component (a2) / constituting unit (a1) is preferably 0.8 or more, more preferably 0.9 or more, preferably 1.2 or less, more preferably 1.1 or less, and even more preferably 1.

[0022] (A) Component may include constituent units other than constituent units (a1) and (a2). (A) The sum of constituent units (a1) and (a2) in the constituent units of component (A) is 90 mol% or more, 95 mol% or more, 98 mol% or more, and 100 mol% or less. (A) The sum of constituent units (a1) and (a2) in the constituent units of component (A) may be 100 mol%.

[0023] Component (B) is a copolymer having a constituent unit derived from compound (b1) represented by the following general formula (b1) and a constituent unit derived from compound (b2) represented by the following general formula (b2).

[0024] [ka]

[0025] [During the ceremony, R 1b , R 2b They may be the same or different, and may be a hydrogen atom or a methyl group. R 3b : Hydrogen atom or -(CO) q O(AO) n X X: Alkyl group or hydrogen atom having 1 to 4 carbon atoms AO: A group selected from ethyleneoxy group and propyleneoxy group. n: The average number of moles added to AO, a number between 1 and 300. p: A number between 0 and 2 (inclusive) q: A number that is either 0 or 1. This indicates...

[0026] [ka]

[0027] [During the ceremony, R 4b , R 5b , R 6b : They may be the same or different, and may be a hydrogen atom, a methyl group, or (CH2) r COOM1 (CH2) r COOM 1 COOM or other (CH2) r COOM 1 They may also form anhydrous compounds, in which case the M, M of those groups 1 It does not exist. M, M 1 : They may be the same or different, and include hydrogen atoms, alkali metals, alkaline earth metals (1 / 2 atom), ammonium groups, alkylammonium groups, or substituted alkylammonium groups. r: A number between 0 and 2 (inclusive) This indicates...

[0028] In general formula (b1), R 1b A hydrogen atom is preferred. In general formula (b1), R 2b A methyl group is preferred. In general formula (b1), R 3b A hydrogen atom is preferred. In general formula (b1), X is preferably a methyl group. In general formula (b1), AO may contain an ethyleneoxy group and a propyleneoxy group. In this case, the ethyleneoxy group and the propyleneoxy group may be randomly bonded or block bonded. AO is preferably an ethyleneoxy group. AO is preferably a compound containing an ethyleneoxy group.

[0029] In general formula (b1), n ​​is the average number of moles of AO added, and is a number between 1 and 300. From the viewpoint of initial fluidity, n is preferably 5 or more, more preferably 10 or more, even more preferably 20 or more, and preferably 200 or less, more preferably 150 or less, and even more preferably 100 or less.

[0030] Component (B) is preferably a copolymer having a constituent unit derived from compound (b1-1) represented by the following general formula (b1-1) and a constituent unit derived from compound (b2) represented by the above general formula (b2). Compound (b1-1) is the compound in the general formula (b1) above where q=0. In formula (b1-1), R1b ~R 3b Preferred embodiments of X, AO, n, and p are the same as those in formula (b1).

[0031] [ka]

[0032] [During the ceremony, R 1b , R 2b They may be the same or different, and may be a hydrogen atom or a methyl group. R 3b : Hydrogen atom or -(CO) q O(AO) n X X: Alkyl group or hydrogen atom having 1 to 4 carbon atoms AO: A group selected from ethyleneoxy group and propyleneoxy group. n: The average number of moles added to AO, a number between 1 and 300. p: A number between 0 and 2 (inclusive) This indicates...

[0033] The admixture for hydraulic compositions of the present invention may contain one or more components (B). When the admixture contains one component (B), it is preferable that, from the viewpoint of storage stability, the admixture contains a copolymer as component (B) having a constituent unit derived from a compound in which p is preferably 1 or more and more than 2 in general formula (b1-1). Furthermore, if the admixture contains two or more components (B), it is preferable that the admixture, from the viewpoint of storage stability, includes a copolymer as component (B) having a constituent unit derived from a compound in which p is preferably 1 or more and 2 or less, more preferably 2, in general formula (b1-1). Furthermore, if the admixture contains two or more components (B), the admixture may, from the viewpoint of storage stability, include as component (B) a copolymer having a constituent unit derived from a compound in which p is preferably 1 or more and 2 or less, more preferably 2, in general formula (b1-1), and a copolymer having a constituent unit derived from a compound in which p is 0 and q is 1 in general formula (b1). From the viewpoint of storage stability of the admixture for hydraulic compositions, the proportion of copolymer having constituent units derived from the compound represented by general formula (b1-1) in component (B) is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 50% by mass or more, even more preferably 60% by mass or more, even more preferably 70% by mass or more, and 100% by mass or less.

[0034] In general formula (b2), R 4b A hydrogen atom is preferred. In general formula (b2), R 5b A methyl group or a hydrogen atom is preferred. In general formula (b2), R 6b A hydrogen atom is preferred. (CH2) r COOM 1 Regarding COOM or other (CH2) r COOM 1 They may also form anhydrous compounds, in which case the M, M of those groups 1 It does not exist. In general formula (b2), M, M 1 These may be the same or different, and each is preferably a hydrogen atom. (CH2) in general formula (b2) r COOM 1 The value of r is preferably 1.

[0035] From the viewpoint of improving fluidity, the total amount of constituent units derived from compound (b1) and compound (b2) in the constituent units of component (B) is preferably 90% by mass or more, more preferably 92% by mass or more, even more preferably 95% by mass or more, and 100% by mass or less. This total amount may be 100% by mass.

[0036] (B) Among the constituent units constituting component (B), the ratio of constituent units derived from compound (b2) to the total of constituent units derived from compound (b1) is preferably 10 mol% or more, more preferably 20 mol% or more, even more preferably 30 mol% or more, even more preferably 40 mol% or more, even more preferably 50 mol% or more, and preferably 99 mol% or less, more preferably 90 mol% or less, and even more preferably 80 mol% or less.

[0037] The weight-average molecular weight of component (B) is preferably 1,000 or more, more preferably 5,000 or more, even more preferably 10,000 or more, even more preferably 30,000 or more, and preferably 1,000,000 or less, more preferably 500,000 or less, even more preferably 150,000 or less, and even more preferably 100,000 or less. This weight-average molecular weight was measured by gel permeation chromatography (GPC) under the following conditions. *GPC conditions Equipment: GPC (HLC-8320GPC), manufactured by Tosoh Corporation. Columns: G4000PWXL + G2500PWXL (manufactured by Tosoh Corporation) Eluent: 0.2M phosphate buffer / CH3CN=9 / 1 Flow rate: 1.0mL / min Column temperature: 40℃ Detection: RI Sample size: 0.2 mg / mL Standard substances: Polyethylene glycol equivalent (monodisperse polyethylene glycol: molecular weight 250,000, 145,000, 87,500, 46,000, 24,000)

[0038] (B) Component is, specifically, (meth)acrylic acid / methoxypolyethylene glycol copolymer, (meth)acrylic acid / vinyl ether copolymer, (meth)acrylic acid / allyl ether copolymer, (meth)acrylic acid / metharyl ether copolymer, (meth)acrylic acid / isoprenyl ether copolymer, Maleic acid / methoxypolyethylene glycol copolymer, Maleic acid / vinyl ether copolymer, Maleic acid / allyl ether copolymer, Maleic acid / metharyl ether copolymer, Maleic acid / isoprenyl ether copolymer, Examples include (meth)acrylic acid / isoprenylate copolymers and maleic acid / isoprenylate copolymers. (Meth)acrylic acid refers to copolymers having constituent units derived from acrylic acid and / or methacrylic acid. Maleic anhydride or fumaric acid may be used instead of maleic acid.

[0039] <Composition and other components of admixtures for hydraulic compositions> The hydraulic composition admixture of the present invention may contain component (A) in an amount of preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 2% by mass or more, from the viewpoint of suppressing discoloration, and preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, from the viewpoint of improving the fluidity of concrete.

[0040] The hydraulic composition admixture of the present invention may contain component (B) in an amount of preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, from the viewpoint of improving the fluidity of concrete, and preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, from the viewpoint of improving storage stability.

[0041] In the hydraulic composition admixture of the present invention, the total content of component (A) and component (B) is preferably 5% by mass or more, more preferably 7% by mass or more, and even more preferably 10% by mass or more, from the viewpoint of improving the fluidity of concrete, and preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less, from the viewpoint of improving storage stability.

[0042] In the admixture for hydraulic compositions of the present invention, the ratio of component (A) to the total content of component (B) is preferably 5% by mass or more, more preferably 7% by mass or more, and even more preferably 10% by mass or more, from the viewpoint of suppressing discoloration, and preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less, from the viewpoint of improving the fluidity of concrete.

[0043] The electrical conductivity of the admixture for hydraulic compositions of the present invention is 11 ms / cm or less, preferably 6 ms / cm or more, more preferably 7 ms / cm or more, and even more preferably 8 ms / cm or more, from the viewpoint of the storage stability of the admixture.

[0044] The admixture for hydraulic compositions of the present invention may optionally contain an air-enhancing agent, a fluidizing agent, a retarder, a rapid strengthening agent, an accelerator, a foaming agent, a thickening agent, a waterproofing agent, an antifoaming agent, a shrinkage reducing agent, a leavening agent, a water-soluble polymer, a surfactant, and the like.

[0045] In the hydraulic composition admixture of the present invention, component (A) has the effect of preventing blackening of the hardened body of the hydraulic composition (for example, the surface of concrete). Therefore, for example, the hydraulic composition admixture of the present invention can be used as a dispersant having a blackening prevention effect. The hydraulic composition admixture of the present invention has excellent storage stability, and even storage stability at high temperatures, and can prevent blackening of the hardened body of the hydraulic composition.

[0046] The admixture for hydraulic compositions of the present invention can be used as a dispersant for hydraulic compositions containing water and hydraulic powder. The admixture for hydraulic compositions of the present invention is used such that the amount of component (A) added (on a solid content basis) is preferably 0.0001% by mass or more, more preferably 0.001% by mass or more, even more preferably 0.002% by mass or more, preferably 0.4% by mass or less, more preferably 0.2% by mass or less, and even more preferably 0.1% by mass or less, relative to the hydraulic powder. Furthermore, the admixture for hydraulic compositions of the present invention is used such that the amount of component (B) added (on a solid content basis) is preferably 0.006% by mass or more, more preferably 0.06% by mass or more, even more preferably 0.08% by mass or more, preferably 1% by mass or less, and even more preferably 0.5% by mass or less, relative to the hydraulic powder.

[0047] From the viewpoint of the cement dispersibility and the remarkable effect of suppressing blackening of the concrete surface of the hydraulic composition admixture of the present invention, the water / hydraulic powder ratio (mass%) of the hydraulic composition is preferably 20% by mass or more, preferably 45% by mass or less, and more preferably 40% by mass or less.

[0048] The hydraulic compositions targeted by the hydraulic admixture of the present invention include cement paste, mortar, concrete, etc., mainly composed of cements, and are not particularly limited, but are preferably used in hydraulic compositions containing a large amount of black fine powder, such as blast furnace slag, fly ash, silica fume, stone powder, calcium carbonate, and lignite. Furthermore, it is preferable to use it in highly fluid self-compacting concrete containing these powders, for example, in the range of 180 mm to 400 mm in mortar flow (according to the JIS R-5201 physical testing method for cement, without tapping).

[0049] Specific examples of hydraulic powders included in hydraulic compositions include Portland cement, blast furnace cement, silica fume cement, fly ash cement, alumina cement, natural gypsum, and by-product gypsum. [Examples]

[0050] <Examples and Comparative Examples> The following components (a) and (b) and water were mixed in the proportions shown in Table 1 to prepare admixtures for hydraulic compositions in the examples and comparative examples.

[0051] <(A) component> Component (A) was a maleic acid / diisobutylene copolymer (maleic acid / diisobutylene (molar ratio) = 50 / 50, weight-average molecular weight = 25,000, degree of neutralization 1). The abbreviations in Table 1 indicate that the constituent units are derived from the following compounds. MLA: A constituent unit derived from maleic acid. DIB: A constituent unit derived from diisobutylene

[0052] <(B) component> Component (B) used the copolymer shown in Table 1. The abbreviations in Table 1 indicate that the constituent units are derived from the following compounds. Component (B) used a copolymer with a degree of neutralization of 0.7. MEPEG: A constituent unit derived from methoxypolyethylene glycol monomethacrylate, i.e., in general formula (b1), R 1b , R 3b is a hydrogen atom, R 2b X is a constituent unit derived from a compound with a methyl group, p = 0, q = 1, AO = ethylene oxy group, n = the value in Table 1, and X = methyl group. TPEG: A constituent unit derived from isoprenyloxypolyethylene glycol, i.e., in general formula (b1), R 1b , R 3b is a hydrogen atom, R 2b The compound is composed of a methyl group, p is 2, q is 0, AO is an ethylene oxy group, n is the value in Table 1, and X is hydrogen. APEG: A constituent unit derived from methoxypolyethylene glycol monoallyl ether, i.e., in general formula (b1), R 1b , R 3b is a hydrogen atom, R 2b The constituent units are derived from a compound where is hydrogen, p is 1, q is 0, AO is an ethylene oxy group, n is the value in Table 1, and X is a methoxy group. MLA: A constituent unit derived from maleic acid, i.e., in general formula (b2), R 4b , R 5b is a hydrogen atom, R 6bCOOM is a constituent unit derived from a compound of a hydrogen atom or sodium. Maleic anhydride (a compound in general formula (b2) that does not contain M) was used for the synthesis of component (B). AA: A constituent unit derived from acrylic acid, i.e., in general formula (b2), R 4b , R 5b , R 6b M is a hydrogen atom, and M is a constituent unit derived from a compound of hydrogen or sodium. MAA: A constituent unit derived from methacrylic acid, i.e., in general formula (b2), R 4b , R 6b is a hydrogen atom, R 5b The methyl group and M are constituent units derived from a compound containing a hydrogen atom or sodium.

[0053] <Other ingredients> NaCl: Sodium chloride ·water

[0054] <Method for evaluating the storage stability of admixtures for hydraulic compositions> The hydraulic admixtures shown in Table 1 were placed in 50 mL screw-cap tubes at a rate of 40 g each and stored at 40°C for one month and at 60°C for one month. After storage, the hydraulic admixtures in the screw-cap tubes were evaluated visually and by measuring the absorbance at a wavelength of 660 nm using an ultraviolet spectrophotometer (UV-160A, Shimadzu Corporation). These evaluations were performed on the hydraulic admixtures at 20°C. The hydraulic admixtures were assigned scores according to the evaluation criteria below. A lower score indicates a hydraulic admixture with superior storage stability. • Evaluation criteria 1: Visually, no separation is observed, and the absorbance (AU) is less than 0.15. 2: Visual inspection reveals no separation, and the absorbance (AU) is between 0.15 and 0.7. 3: Visual inspection indicates no separation, and the absorbance (AU) is greater than 0.7. 4. Separation is visually observed, and the thickness of the separated layer is between 0.5 mm and 20 mm from the top of the meniscus. 5. Separation is visually observed, and the thickness of the separated layer is more than 20 mm from the top of the meniscus.

[0055] <Method for measuring electrical conductivity> 40 g of the admixture for hydraulic compositions was placed in a 50 mL screw-cap tube, and the electrical conductivity of the admixture was measured using an electrical conductivity meter (CM-20S (TOA Electrons Ltd)). The electrical conductivity was measured by immersing the electrodes of an electrical conductivity meter in the admixture and taking the value after 2 minutes. The measurement was performed under conditions where the electrical conductivity measurement scale was 100 ms / cm and the temperature of the admixture for hydraulic compositions was 20°C.

[0056] [Table 1]

[0057] When the admixtures for hydraulic compositions in the examples were added to the hydraulic compositions and the surface of the hardened bodies of the hydraulic compositions was observed, the proportion of the blackened area to the total area was 3% or less in all examples, indicating that a blackening suppression effect was obtained.

Claims

1. An admixture for hydraulic compositions comprising: (A) a copolymer having constituent units (a1) derived from an olefin with 6 to 14 carbon atoms and constituent units (a2) derived from one or more compounds selected from maleic acid and fumaric acid, with a weight-average molecular weight of 10,000 to 100,000 [hereinafter referred to as component (A)] in a quantity of 0.5% to 15% by mass; (B) a copolymer having constituent units derived from a compound (b1) represented by the following general formula (b1) and constituent units derived from a compound (b2) represented by the following general formula (b2) [hereinafter referred to as component (B)] in a quantity of 3% to 50% by mass; and water, wherein the ratio of the content of component (A) to the total content of components (A) and (B) is 5% to 70% by mass, and the electrical conductivity is 11 mS / cm or less. 【Chemistry 1】 [During the ceremony, R １ｂ , R ２ｂ : They may be the same or different, and may be a hydrogen atom or a methyl group R ３ｂ : Hydrogen atom or -(CO) ｑ O (AO) ｎ X X: Alkyl or hydrogen atom having 1 to 4 carbon atoms AO: A group selected from ethyleneoxy group and propyleneoxy group. n: The average number of moles of AO added, a number between 1 and 300. p: A number between 0 and 2 (inclusive) q: A number of 0s or 1s This indicates... 【Chemistry 2】 [During the ceremony, R ４ｂ 、 R ５ｂ 、 R ６ｂ : They may be the same or different, and are a hydrogen atom, a methyl group or (CH ２ ) ｒ COOM １ wherein (CH ２ ) ｒ COOM １ may form an anhydride with COOM or another (CH ２ ) ｒ COOM １ in which case M and M １ of those groups do not exist. M, M １ : They may be the same or different, and include hydrogen atoms, alkali metals, alkaline earth metals (1 / 2 atom), ammonium groups, alkylammonium groups, or substituted alkylammonium groups. r: A number between 0 and 2 (inclusive) This indicates...

2. The admixture for hydraulic compositions according to claim 1, comprising as component (B), a copolymer having a constituent unit derived from a compound in general formula (b1) where p is 1 or more and q is 0.

3. The admixture for hydraulic compositions according to claim 1 or 2, comprising as component (B), a copolymer having a constituent unit derived from a compound in general formula (b1) where p is 2 and q is 0.

4. The admixture for hydraulic compositions according to any one of claims 1 to 3, comprising as component (B), a copolymer having a constituent unit derived from a compound in general formula (b1) where p is 0 and q is 1.

5. (B) An admixture for hydraulic compositions according to any one of claims 1 to 4, comprising two or more components.

6. (B) The admixture for hydraulic compositions according to any one of claims 1 to 5, wherein the proportion of copolymer having a constituent unit derived from a compound in general formula (b1) where p is 1 or more and q is 0 is 60% by mass or more in component (B).

7. An admixture for hydraulic compositions according to any one of claims 1 to 6, comprising a total of 10% by mass or more and 30% by mass or less of component (A) and component (B).

8. (A) The molar ratio of constituent unit (a1) to constituent unit (a2) constituting component (A) is 0.8 or more and 1.2 or less, as constituent unit (a2) / constituting unit (a1), an admixture for hydraulic compositions according to any one of claims 1 to 7.

Images