Additive for hydraulic composition

Abstract

To provide an additive for a hydraulic composition which is excellent in suppressing blackening on a surface of a hardened hydraulic composition, and to provide an admixture composition for the hydraulic composition, a hydraulic composition in which the blackening on the surface during curing is suppressed, and a method for producing the same.SOLUTION: An additive for a hydraulic composition comprises (a) a copolymer (hereinafter referred to as (a) component), and water. The (a) component comprises, as constituent monomers: a constituent monomer (a1) which is a 6-10C or more olefin; and a constituent monomer (a2), which is one or more unsaturated dibasic acids selected from maleic acid, fumaric acid, and their salts, and maleic anhydride. In the (a) component, a molar ratio (a1) / (a2) of the constituent monomer (a1) to the constituent monomer (a2) in the constituent monomer is 4 / 6 or more and 6 / 4 or less; and a weight average molecular weight thereof is 10,000 or more and 40,000 or less. A pH at 25°C is 9.0 or more and less than 11.0 when a content of the (a) component is 20 mass%.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an additive for a hydraulic composition, an admixture composition for a hydraulic composition, a hydraulic composition, and a method for producing the same. [Background technology]

[0002] In recent years, in order to achieve the SDGs, there has been an effort to develop environmentally friendly infrastructure from an ESG perspective. Attempts have been made to partially substitute cement with fly ash, an industrial by-product of coal-fired power generation, and to substitute natural sand with crushed stone and sand obtained by crushing rocks. However, fly ash contains unburned carbon remaining after incineration, and crushed stone and crushed sand contain charcoal depending on their place of origin and type. When these are used as concrete materials, the above carbon components appear on the concrete surface, causing problems such as a loss of aesthetic appearance and making it difficult to clean formwork, etc.

[0003] In the past studies, therefore, attempts have been made to reduce the above-mentioned blackening by dispersing the above-mentioned carbon content using a surfactant or a polymer. Patent Document 1 discloses a concrete admixture containing one or more surfactants selected from a nonionic surfactant having an HLB value of 17.5 to 19.5 and containing 15 to 200 ethylene oxide groups per molecule, and an anionic surfactant having 15 to 200 ethylene oxide groups per molecule. Patent Document 2 discloses an agent for inhibiting the precipitation of black matter on the surface of hardened concrete, which contains 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 hardened concrete, which comprises adding 0.0001 to 0.1 parts by weight, calculated as solid content, of a copolymer of a monoolefin having 6 to 10 carbon atoms and maleic acid or a salt thereof to 100 parts by weight of cement. Patent Document 3 discloses an additive for preventing blackening of a hardened hydraulic composition, which comprises one or more kinds of phosphoric acid esters or salts thereof, such as a mixture containing a phosphoric acid monoester having a specific group such as an alkyl ether group or a salt thereof and a phosphoric acid diester having a specific group such as an alkyl ether group or a salt thereof in a specific weight ratio. Patent Document 4 describes a dispersant made of a polymer composition obtained by mixing a mixture of a copolymer of an α-olefin and an unsaturated dibasic acid, a composition containing water, and a first neutralizing agent made of an amine-type neutralizing agent with a second neutralizing agent made of an alkali metal hydroxide. 2 / g of carbon material, and an aqueous medium. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-234763 A [Patent Document 2] JP 2004-83303 A [Patent Document 3] JP 2005-213082 A [Patent Document 4] JP 2015-52029 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, existing concrete surface darkening inhibitors have a problem in that a large amount needs to be added in order to obtain a sufficient darkening inhibition effect. The present invention provides an additive for a hydraulic composition, which is excellent in the effect of suppressing darkening occurring on the surface of a hardened hydraulic composition, an admixture composition for a hydraulic composition, a hydraulic composition in which darkening occurring on the surface during hardening is suppressed, and a method for producing the same. [Means for solving the problem]

[0006] The present invention relates to (a) an additive for hydraulic compositions, which contains, as constituent monomers, constituent monomer (a1) which is an olefin having 6 to 10 carbon atoms and constituent monomer (a2) which is one or more unsaturated dibasic acids selected from maleic acid, fumaric acid, and their salts, and maleic anhydride, in which the molar ratio (a1) / (a2) of constituent monomer (a1) to constituent monomer (a2) in the constituent monomers is 4 / 6 to 6 / 4 and the weight average molecular weight is 10,000 to 40,000 (hereinafter referred to as component (a)), and water, and which has a pH of 9.0 to less than 11.0 at 25°C when the content of component (a) is 20% by mass.

[0007] The present invention also relates to an admixture composition for hydraulic compositions, which contains the additive for hydraulic compositions of the present invention and (b) a polycarboxylic acid-based dispersant (hereinafter referred to as component (b)).

[0008] The present invention also relates to a hydraulic composition containing the additive for hydraulic compositions of the present invention, component (b), hydraulic powder, and water.

[0009] The present invention also relates to a method for producing a hydraulic composition, which comprises mixing the additive for hydraulic compositions of the present invention, component (b), hydraulic powder, and water. Effect of the Invention

[0010] According to the present invention, it is possible to provide an additive for a hydraulic composition, which is excellent in the effect of suppressing darkening occurring on the surface of a hardened hydraulic composition, an admixture composition for a hydraulic composition, a hydraulic composition in which darkening occurring on the surface during hardening is suppressed, and a method for producing the same.

[0011] In recent years, the SDGs have been advocated for the realization of a sustainable society. This invention is a 2 By reducing emissions, it is believed that this technology could contribute to SDGs 7, 9, 11, 12, and 13, for example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present inventors have found that when an additive for hydraulic compositions, which contains component (a) and water and has a pH of 9.0 or more and less than 11.0 at 25°C when the content of component (a) is 20% by mass, is added to a hydraulic composition, it has an excellent effect of suppressing blackening occurring on the surface of the hardened hydraulic composition. The reason why such an effect is exhibited is not necessarily clear, but is presumed to be as follows. The blackening in the hydraulic composition is due to the carbon component contained in a small amount, which is originally adsorbed to fly ash, crushed stone, crushed sand, etc., and it is believed that the specific gravity difference in the slurry increases only when the carbon component is dispersed by a cement dispersant, and the carbon component separates from the hydraulic composition slurry and appears on the surface of the hardened body. When a hydrophobic copolymer of an olefin and an unsaturated dibasic acid such as component (a) of the present invention is added to the slurry of the hydraulic composition, the hydrophobic olefin part adsorbs the carbon component, and the carboxy group of the unsaturated dibasic acid part adsorbs the carbon component to the calcium cationite on the cement particle surface, thereby binding the carbon component to the cement particle surface, thereby suppressing the separation due to the specific gravity difference. However, when the carboxy group of the unsaturated dibasic acid part of the above copolymer is completely neutralized, the hydrophilicity of the copolymer becomes excessively high, the interaction force with the carbon component decreases, and the blackening suppression effect is reduced. On the other hand, if the degree of neutralization of the carboxyl groups in the unsaturated dibasic acid moiety is low, the hydrophobicity of the copolymer becomes excessively high, which is thought to make it difficult to anchor the carbon component to the hydrophilic surface of the cement particle. The additive for hydraulic compositions of the present invention contains component (a), which is a copolymer of a specific olefin and an unsaturated dibasic acid, and water. When the content of component (a) is 20% by mass, the degree of neutralization (hydrophilicity / hydrophobicity) of the copolymer is adjusted so that the pH at 25°C is 9.0 or more and less than 11.0. It is believed that this allows the copolymer to effectively interact with both the carbon component and the cement particles when added to a hydraulic composition, thereby exerting an excellent blackening inhibition effect.

[0013] [Additives for hydraulic compositions] The additive composition for hydraulic compositions of the present invention contains, as component (a), a constituent monomer (a1) which is an olefin having 6 to 10 carbon atoms and a constituent monomer (a2) which is one or more unsaturated dibasic acids selected from maleic acid, fumaric acid, and salts thereof, and maleic anhydride, as constituent monomers, in which the molar ratio (a1) / (a2) of the constituent monomers (a1) to (a2) is 4 / 6 or more and 6 / 4 or less, and the weight average molecular weight is 10,000 or more and 40,000 or less.

[0014] The constituent monomer (a1) is an olefin having 6 to 10 carbon atoms. The carbon number of the constituent monomer (a1) is 6 or more, preferably 7 or more, and 10 or less, preferably 9 or less, and more preferably 8, from the viewpoints of copolymerizability and blackening suppression effect. The constituent monomer (a1) may be one or more selected from diisobutylene, 1-hexene, 1-octene, and isobutylene. From the viewpoint of copolymerizability and blackening suppression effect, it is preferably one or more selected from diisobutylene and isobutylene, and more preferably diisobutylene.

[0015] The constituent monomer (a2) is one or more unsaturated dibasic acids selected from maleic acid, fumaric acid, and salts thereof, and maleic anhydride. Examples of the salt 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. From the viewpoint of copolymerizability, the constituent monomer (a2) is preferably at least one selected from maleic anhydride and fumaric acid, and more preferably maleic anhydride.

[0016] Examples of component (a) include copolymers of diisobutylene and one or more selected from maleic acid, fumaric acid, and salts thereof, and maleic anhydride. From the viewpoint of copolymerizability and blackening inhibition effect, copolymers of diisobutylene and one or more selected from maleic anhydride, maleic acid, and fumaric acid are preferred.

[0017] The weight average molecular weight of component (a) (gel permeation chromatography / polystyrene sulfonic acid equivalent) is preferably 10,000 or more, more preferably 15,000 or more, even more preferably 20,000 or more, and preferably 40,000 or less, more preferably 30,000 or less, from the viewpoint of handling of the aqueous solution and the effect of suppressing blackening. Component (a) can be produced, for example, in accordance with the method described in JP-A-55-40797. In the present invention, the weight average molecular weight of component (a) is the value converted into that of an unneutralized acid compound.

[0018] The weight average molecular weight of the component (a) was measured by GPC (gel permeation chromatography) under the following conditions. The weight average molecular weight was calculated based on a calibration curve prepared in advance. The following standard samples were used to prepare the calibration curve. Measuring device: HLC-8120GPC (Tosoh Corporation) Column: TSK α-M + α-M (both manufactured by Tosoh Corporation) Column temperature: 40℃ Detector: RI Eluent:H 3 PO 4 (60mmol / L) and LiBr (50mmol / L) in N,N-dimethylformamide Flow rate: 1.0mL / min Sample concentration: 0.1% by mass (solids) Sample injection volume: 0.1 mL Standard sample: Tosoh polystyrene 5.26 x 10 2 , 1.02×10 5 , 8.42×10 6 ; Nishio Kogyo Co., Ltd. polystyrene 4.0 x 10 3 , 3.0×104 , 9.0×10 5 (The numbers indicate molecular weights.)

[0019] Among the constituent monomers of component (a), the molar ratio (a1) / (a2) of the constituent monomer (a1) to the constituent monomer (a2) is, from the viewpoints of copolymerizability and the blackening suppression effect, 40 / 60 or more, preferably 45 / 55 or more, and 60 / 40 or less, preferably 55 / 45 or less.

[0020] The component (a) may contain constituent monomers other than the constituent monomer (a1) and the constituent monomer (a2). Among the constituent monomers of component (a), the total of constituent monomer (a1) and constituent monomer (a2) is 90 mol% or more, 95 mol% or more, 98 mol% or more, and 100 mol% or less. Among the constituent monomers of component (a), the total of constituent monomer (a1) and constituent monomer (a2) may be 100 mol%.

[0021] The degree of neutralization of the component (a) is adjusted so that the pH at 25° C. is 9.0 or more and less than 11.0 when the content of the component (a) in the additive for hydraulic compositions is 20 mass %. When the content of the (a) component in the additive for hydraulic compositions is 20% by mass, the pH at 25°C is 9.0 or more, preferably 9.5 or more, and less than 11.0, preferably 10.5 or less, from the viewpoints of suppressing blackening, storage stability of the aqueous solution, and handling. The degree of neutralization of the (a) component is adjusted, for example, by adding an alkaline agent such as sodium hydroxide to the hydraulic composition additive containing the unneutralized (a) component and water, so that the pH at 25°C when the content of the (a) component is 20 mass% is 9.0 or more and less than 11.0. The pH is measured at 25° C. using an electrode-type pH meter (eg, manufactured by Horiba, Ltd.).

[0022] The additive for hydraulic compositions of the present invention contains the component (a) in an amount of preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, from the viewpoints of storage stability and handling of the aqueous solution. In the present invention, the mass of component (a) is defined as a value converted into an unneutralized acid compound.

[0023] The additive for hydraulic compositions of the present invention contains water. In the additive for hydraulic compositions of the present invention, the remainder other than component (a) is water. The additive for hydraulic compositions of the present invention contains water in an amount of preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less, from the viewpoints of storage stability and handling of the aqueous solution.

[0024] [Admixture composition for hydraulic composition] The present invention provides an admixture composition for hydraulic compositions, which contains the additive for hydraulic compositions of the present invention and (b) a polycarboxylic acid-based dispersant (hereinafter referred to as component (b)). The admixture composition for hydraulic compositions of the present invention contains the additive for hydraulic compositions of the present invention, and thus contains component (a). Component (a) is the same as that described in the additive for hydraulic compositions of the present invention. The admixture composition for hydraulic compositions of the present invention can be appropriately applied with the embodiments described in the additive for hydraulic compositions of the present invention.

[0025] The polycarboxylic acid dispersant of component (b) is preferably a copolymer containing, as constituent monomers, a constituent monomer (b1) represented by the following general formula (b1) and a constituent monomer (b2) represented by the following general formula (b2):

[0026] [ka]

[0027] [During the ceremony, R 1b , R 2b 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: 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: average number of moles of AO added, 1 to 300 p: a number between 0 and 2 q: a number 0 or 1 Indicates the following.

[0028] [ka]

[0029] [During the ceremony, R 4b , R 5b , R 6b may be the same or different, and may be a hydrogen atom, a methyl group, or (CH 2 ) r COOM 1 and (CH 2 ) r COOM 1 COOM or other (CH 2 ) r COOM 1 In this case, the M and M groups may form an anhydride. 1 does not exist. M, M 1 may be the same or different, and are 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 between 0 and 2 Indicates the following.

[0030] In general formula (b1), R 1b is preferably a hydrogen atom. In general formula (b1), R 2b is preferably a methyl group. In general formula (b1), R 3b is preferably a hydrogen atom. In the general formula (b1), X is preferably a methyl group. In the 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 a random bond or a block bond. AO is preferably an ethyleneoxy group. AO preferably contains an ethyleneoxy group.

[0031] In the general formula (b1), n ​​is the average number of moles of AO added, and is a number from 1 to 300. From the viewpoint of improving the fluidity of the uncured hydraulic composition, n is preferably a number of 5 or more, more preferably 10 or more, even more preferably 20 or more, and is preferably a number of 200 or less, more preferably 150 or less, even more preferably 100 or less, and still more preferably 50 or less.

[0032] In general formula (b2), R 4b is preferably a hydrogen atom. In general formula (b2), R 5b is preferably a methyl group or a hydrogen atom. In general formula (b2), R 6b is preferably a hydrogen atom. (CH 2 ) r COOM 1 Regarding COOM or other (CH 2 ) r COOM 1 In this case, the M and M groups may form an anhydride. 1 does not exist. In general formula (b2), M, M 1 may be the same or different, and each is preferably a hydrogen atom. (CH 2 ) r COOM 1 In the above formula, r is preferably 1.

[0033] From the viewpoint of improving the fluidity of the uncured hydraulic composition, the total amount of the constituent monomers (b1) and (b2) among the constituent monomers constituting the component (b) is preferably 90 mol % or more, more preferably 92 mol % or more, and even more preferably 95 mol % or more and 100 mol % or less. This total amount may be 100 mol %.

[0034] From the viewpoint of improving the fluidity of the uncured hydraulic composition, the ratio of the constituent monomer (b2) to the total of the constituent monomer (b1) and the constituent monomer (b2) among the constituent monomers constituting the component (b) is preferably 10 mol % or more, more preferably 20 mol % or more, even more preferably 30 mol % or more, still more preferably 40 mol % or more, still more preferably 50 mol % or more, still more preferably 60 mol % or more, still more preferably 70 mol % or more, and preferably 99 mol % or less, more preferably 90 mol % or less, and still more preferably 80 mol % or less.

[0035] From the viewpoint of improving the fluidity of the uncured hydraulic composition, the weight average molecular weight of the (b) component is preferably 1,000 or more, more preferably 5,000 or more, even more preferably 10,000 or more, still 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, still more preferably 100,000 or less, still more preferably 50,000 or less. This weight average molecular weight is measured by gel permeation chromatography (GPC) under the following conditions. *GPC conditions Equipment: GPC (HLC-8320GPC) manufactured by Tosoh Corporation Column: G4000PWXL+G2500PWXL (Tosoh Corporation) Eluent: 0.2M phosphate buffer / CH 3 CN=9 / 1 Flow rate: 1.0mL / min Column temperature: 40℃ Detection: RI Sample size: 0.2mg / mL Standard substance: Polyethylene glycol equivalent (monodisperse polyethylene glycol: molecular weight 250,000, 145,000, 87,500, 46,000, 24,000) In the present invention, the weight average molecular weight of the component (b) is the value calculated as an unneutralized acid compound.

[0036] Specifically, the component (b) is (Meth)acrylic acid / methoxypolyethylene glycol copolymer, (meth)acrylic acid / vinyl ether copolymer, (Meth)acrylic acid / allyl ether copolymer, (Meth)acrylic acid / methallyl 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 / methallyl ether copolymer, Maleic acid / isoprenyl ether copolymer, Examples of the copolymer include (meth)acrylic acid / methoxypolyethylene glycol copolymers, and (meth)acrylic acid refers to copolymers having structural units derived from acrylic acid and / or methacrylic acid. Maleic anhydride and fumaric acid may be used instead of maleic acid.

[0037] The admixture composition for hydraulic compositions of the present invention may contain the component (a) in an amount of preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and even more preferably 2.0% by mass or more from the viewpoint of suppressing blackening, and in an amount of preferably 15.0% by mass or less, more preferably 10.0% by mass or less, and even more preferably 5.0% by mass or less from the viewpoint of improving the fluidity of the uncured hydraulic composition.

[0038] The admixture composition for hydraulic compositions of the present invention may contain the component (b) in an amount of preferably 1.0% by mass or more, more preferably 5.0% by mass or more, and even more preferably 10.0% by mass or more from the viewpoint of improving the fluidity of the uncured hydraulic composition, and in an amount of preferably 50.0% by mass or less, more preferably 40.0% by mass or less, and even more preferably 30.0% by mass or less from the viewpoint of the storage stability of the admixture composition for hydraulic compositions. In the present invention, the mass of the component (b) is defined as a value converted into an unneutralized acid type compound.

[0039] In the admixture composition for hydraulic compositions of the present invention, the mass ratio (b) / (a) of the content of the component (a) to the content of the component (b) is preferably 5 or more, more preferably 20 or more, and even more preferably 35 or more, from the viewpoint of improving the fluidity of the uncured hydraulic composition, and is preferably 75 or less, more preferably 60 or less, and even more preferably 45 or less, from the viewpoint of the blackening suppression effect.

[0040] The admixture composition for hydraulic composition of the present invention may contain water. When the admixture composition for hydraulic composition of the present invention contains water, the admixture composition for hydraulic composition of the present invention contains water in an amount of preferably 50% by mass or more, more preferably 60% by mass or more from the viewpoint of the handling property of the admixture composition for hydraulic composition, and preferably 90% by mass or less, more preferably 80% by mass or less from the viewpoint of improving the fluidity of the uncured hydraulic composition and suppressing blackening.

[0041] The admixture composition for hydraulic compositions of the present invention may contain a defoaming agent as component (c) from the viewpoint of improving the strength of the hardened hydraulic composition and the fluidity of the unhardened hydraulic composition. As the defoaming agent, a silicone-based defoaming agent, a fatty acid ester-based defoaming agent, an ether-based defoaming agent, or an aliphatic amine-based defoaming agent is preferred, of which dimethylpolysiloxane is more preferred among the silicone-based defoaming agents, polyalkylene glycol fatty acid ester is more preferred among the fatty acid ester-based defoaming agents, polyalkylene glycol alkyl ether is more preferred among the ether-based defoaming agents, and alkyldimethylamine or a salt thereof is more preferred among the aliphatic amine-based defoaming agents.

[0042] When the admixture composition for hydraulic compositions of the present invention contains the component (c), it contains the component (c) in an amount of preferably 0.001 mass % or more, more preferably 0.01 mass % or more, and preferably 1.0 mass % or less, more preferably 0.1 mass % or less.

[0043] The admixture composition for hydraulic compositions of the present invention may optionally contain an air-enhancing agent, a plasticizer, a retarder, an early strength agent, an accelerator, a foaming agent, a thickener, a waterproofing agent, a shrinkage reducing agent, an expanding agent, a water-soluble polymer, a surfactant, and the like (however, those corresponding to components (a), (b), and (c) are excluded).

[0044] [Method for producing admixture composition for hydraulic composition] The present invention provides a method for producing an admixture composition for a hydraulic composition, which comprises mixing the additive for a hydraulic composition of the present invention with (b). In the method for producing the admixture composition for hydraulic compositions of the present invention, water can be further mixed. In the method for producing the admixture composition for hydraulic compositions of the present invention, the above-mentioned component (c) can be further mixed.

[0045] In the method for producing the admixture composition for hydraulic compositions of the present invention, the additive for hydraulic compositions of the present invention is mixed to mix component (a). Component (a) is the same as that described in the additive for hydraulic compositions of the present invention. The components (b) and (c) are the same as those described in the admixture composition for hydraulic compositions of the present invention. The method for producing the admixture composition for hydraulic compositions of the present invention can be appropriately applied to the aspects described for the additive for hydraulic compositions of the present invention and the admixture for hydraulic compositions of the present invention. In the manufacturing method of the admixture composition for hydraulic composition of the present invention, the mixing amounts of the (a) component, the (b) component, and the (c) component, and the mass ratio (b) / (a) can be applied by replacing the contents of each component described in the admixture composition for hydraulic composition of the present invention with the mixing amounts.

[0046] [Hydraulic composition] The present invention provides a hydraulic composition containing the additive for hydraulic compositions of the present invention, component (b), hydraulic powder, and water. The hydraulic composition of the present invention may further contain the above-mentioned component (c). The hydraulic composition of the present invention contains the additive for hydraulic compositions of the present invention, and thus contains component (a). Component (a) is the same as that described in the additive for hydraulic compositions of the present invention. Components (b) and (c) are the same as those described in the admixture composition for hydraulic compositions of the present invention. The hydraulic composition of the present invention can be appropriately applied with the embodiments described in the additive for hydraulic compositions of the present invention, and the admixture composition for hydraulic compositions and the manufacturing method thereof of the present invention.

[0047] The hydraulic powder used in the hydraulic composition of the present invention is a powder that hardens when mixed with water, and examples thereof include ordinary Portland cement, high-early-strength Portland cement, ultra-high-early-strength Portland cement, sulfate-resistant Portland cement, low-heat Portland cement, white Portland cement, and ecocement (e.g., JIS R5214, etc.). Among these, from the viewpoint of shortening the time required for the hydraulic composition to reach a required strength, a cement selected from early-early-strength Portland cement, ordinary Portland cement, sulfate-resistant Portland cement, and white Portland cement is preferred, and a cement selected from early-early-strength Portland cement and ordinary Portland cement is more preferred.

[0048] From the viewpoint of enjoying the effects of the present invention, the hydraulic powder may include blast furnace slag, fly ash, silica fume, stone powder, calcium carbonate, lignite, etc., which contain a large amount of black fine powder. As the hydraulic powder, blast furnace cement, fly ash cement, or silica fume cement, which is a mixture of cement with blast furnace slag, fly ash, silica fume, etc., may be used.

[0049] The hydraulic composition of the present invention contains, relative to 100 parts by mass of hydraulic powder, preferably 0.0001 parts by mass or more of component (a) from the viewpoint of the blackening inhibition effect, more preferably 0.0005 parts by mass or more, even more preferably 0.001 parts by mass or more, and still more preferably 0.005 parts by mass or more, and from the viewpoint of the fluidity of the uncured hydraulic composition, preferably 0.4 parts by mass or less, more preferably 0.2 parts by mass or less, even more preferably 0.1 parts by mass or less, still more preferably 0.05 parts by mass or less, and still more preferably 0.01 parts by mass or less.

[0050] The hydraulic composition of the present invention contains, relative to 100 parts by mass of hydraulic powder, preferably 0.005 parts by mass or more of component (b) from the viewpoint of the fluidity of the uncured hydraulic composition, more preferably 0.01 parts by mass or more, even more preferably 0.05 parts by mass or more, and even more preferably 0.1 parts by mass or more, and from the viewpoint of the strength expression of the hydraulic composition, preferably 2 parts by mass or less, more preferably 1 part by mass or less, and even more preferably 0.5 parts by mass or less.

[0051] In the hydraulic composition of the present invention, the mass ratio (b) / (a) of the content of the component (a) to the content of the component (b) is preferably 5 or more, more preferably 20 or more, and even more preferably 35 or more, from the viewpoint of improving the fluidity of the uncured hydraulic composition, and is preferably 75 or less, more preferably 60 or less, and even more preferably 45 or less, from the viewpoint of the blackening suppression effect.

[0052] When the hydraulic composition of the present invention contains the component (c), the hydraulic composition contains the component (c) in an amount of preferably 0.00000005 parts by mass or more, more preferably 0.000005 parts by mass or more, even more preferably 0.00001 parts by mass or more, even more preferably 0.00005 parts by mass or more, even more preferably 0.0001 parts by mass or more, even more preferably 0.0005 parts by mass or more, even more preferably 0.0001 parts by mass or more, even more preferably 0.0005 parts by mass or more, even more preferably 0.001 parts by mass or more, even more preferably 0.005 parts by mass or more, even more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, more preferably 0.1 parts by mass or less, and even more preferably 0.05 parts by mass or less, relative to 100 parts by mass of the hydraulic powder.

[0053] In the hydraulic composition of the present invention, from the viewpoint of the blackening suppression effect, the water / hydraulic powder ratio (W / C) is preferably 10 mass% or more, more preferably 15 mass% or more, even more preferably 20 mass% or more, still more preferably 30 mass% or more, still more preferably 35 mass% or more, and preferably 50 mass% or less, more preferably 45 mass% or less. Here, the water / hydraulic powder ratio (W / C) is the mass percentage (mass%) of water and hydraulic powder in the hydraulic composition, and is calculated as water / hydraulic powder×100. In addition, when the hydraulic powder includes powders selected from powders having pozzolanic action, powders having latent hydraulic properties, and stone powder (calcium carbonate powder) in addition to powders having properties that harden through hydration reactions such as cement, the amounts of these powders are also included in the amount of hydraulic powder in this invention. In addition, when the powder having properties that harden through hydration reactions contains a high-strength admixture, the amount of the high-strength admixture is also included in the amount of hydraulic powder. This also applies to other parts by mass that are related to the mass of the hydraulic powder.

[0054] The hydraulic composition of the present invention may contain aggregate. Examples of aggregates include aggregates selected from fine aggregates and coarse aggregates. Examples of fine aggregates include those specified by number 2311 in JISA0203-2014. Examples of fine aggregates include river sand, land sand, mountain sand, sea sand, lime sand, silica sand and crushed sands thereof, blast furnace slag fine aggregate, ferronickel slag fine aggregate, lightweight fine aggregate (artificial and natural), and recycled fine aggregate. Examples of coarse aggregates include those specified by number 2312 in JIS A 0203-2014. For example, examples of coarse aggregates include river gravel, land gravel, mountain gravel, sea gravel, lime gravel, crushed stones thereof, blast furnace slag coarse aggregate, ferronickel slag coarse aggregate, lightweight coarse aggregate (artificial and natural), and recycled coarse aggregate. Fine aggregates and coarse aggregates of different types may be mixed and used, or a single type may be used.

[0055] When the hydraulic composition is concrete, the amount of coarse aggregate used is preferably 50% or more, more preferably 55% or more, even more preferably 60% or more, in terms of the expression of strength of the hydraulic composition, reducing the amount of hydraulic powder such as cement used, and improving the filling property into a formwork, and is preferably 100% or less, more preferably 90% or less, even more preferably 80% or less in bulk volume, from the viewpoint of improving the filling property of the hydraulic composition and reducing the amount of hydraulic powder such as cement used. 3 It is the ratio of the volume of coarse aggregate (including voids) in the concrete. When the hydraulic composition is concrete, the amount of fine aggregate used is preferably 500 kg / m from the viewpoint of improving the filling property into a formwork or the like. 3 More preferably, 600 kg / m 3 More preferably, 700 kg / m 3 and preferably 1000 kg / m 3 Less than or equal to 900 kg / m 3 The following is the result. When the hydraulic composition is a mortar, the amount of fine aggregate used is preferably 800 kg / m 3 More preferably, 900kg / m 3 More preferably, 1000 kg / m 3 and preferably 2000 kg / m 3 Less than or equal to 1800 kg / m 3 More preferably, 1700 kg / m 3 The following is the result.

[0056] The hardened body obtained from the hydraulic composition of the present invention has an excellent effect of suppressing the occurrence of blackening on the surface of the hardened body, and therefore can be used for structures and concrete products. Examples of structures include main parts such as columns, beams, floor plates, and bearing walls of reinforced concrete and steel-framed reinforced concrete buildings, and civil engineering structures such as roads, bridges, piers, girders, tunnels, waterways, dams, sewers, breakwaters, and retaining walls. Examples of concrete products include vibration-molded products such as culverts, gutters, and segments, and centrifugal-molded products such as poles, piles, and Hume pipes.

[0057] [Method of manufacturing hydraulic composition] The present invention provides a method for producing a hydraulic composition, which comprises mixing the additive for hydraulic compositions of the present invention, component (b), hydraulic powder, and water. In the method for producing the hydraulic composition of the present invention, the above-mentioned component (c) can be further mixed.

[0058] In the method for producing a hydraulic composition of the present invention, the additive for hydraulic compositions of the present invention is mixed to mix component (a). Component (a) is the same as that described in the additive for hydraulic compositions of the present invention. Components (b) and (c) are the same as those described in the admixture composition for hydraulic compositions of the present invention. The manufacturing method of the hydraulic composition of the present invention can appropriately apply the embodiments described in the additive for hydraulic composition of the present invention, the admixture composition for hydraulic composition and its manufacturing method of the present invention, and the hydraulic composition of the present invention. In the manufacturing method of the hydraulic composition of the present invention, the mixing amounts of the (a), (b), and (c) components and the mass ratio (b) / (a) can be applied by replacing the contents of each component described in the hydraulic composition of the present invention with the mixing amounts.

[0059] The method for producing the hydraulic composition of the present invention includes a method in which the additive for hydraulic compositions of the present invention and component (b) are separately added to water to prepare mixed water, and the mixed water is mixed with hydraulic powder. EXAMPLES

[0060] The materials used in the examples and comparative examples are shown below. <Component (a)> (a1): Diisobutylene / maleic anhydride copolymer (diisobutylene / maleic anhydride (molar ratio) = 50 / 50, weight average molecular weight = 25,000) <(b) Component> (b1): Methacrylic acid (MAA) / methoxypolyethylene glycol (25) monomethacrylate (MEPEG) copolymer (MAA: R in the general formula (b2) 4b , R 6b is a hydrogen atom, R 5bConstituent monomer (b2) is a compound in which R is a methyl group and M is a hydrogen atom; MEPEG: In the general formula (b1), 1b , R 3b is a hydrogen atom, R 2b Constituent monomer (b1) in which AO is a methyl group, p is 0, q is 1, AO is an ethyleneoxy group, n is 25, and X is a methyl group, MAA / MEPEG (molar ratio) = 75 / 25, weight average molecular weight = 40,000) <(c) component> (c1): Defoamer (Antifoamer No. 21, Kao Corporation)

[0061] Cement: Ordinary Portland cement (manufactured by Taiheiyo Cement Corporation, specific gravity 3.16) Fly ash: JIS type II, Chubu fly ash (manufactured by Techno Chubu Co., Ltd., specific gravity 2.70) Water: Tap water (Wakayama City tap water, specific gravity 1.00) Fine aggregate: Mountain sand (from Joyo, Kyoto City, coarse grain ratio 2.73, surface dry specific gravity 2.58)

[0062] <Examples and Comparative Examples> Preparation of the additive for hydraulic composition of the present invention According to the method described in JP-A-55-40797, the component (a) and water described in Table 1 were mixed, and a 48% aqueous solution of sodium hydroxide (manufactured by Kanto Chemical Co., Ltd.) diluted with tap water was added thereto to adjust the solid content concentration of the component (a) to 20 mass% and the pH at 25°C to the value in Table 1, thereby preparing an additive for hydraulic compositions. The pH of the additive for hydraulic compositions was measured at 25°C using an electrode-type pH meter (manufactured by Horiba, Ltd.). The pH measurements were also performed in the other examples and comparative examples according to the same method.

[0063] Preparation of hydraulic composition slurry The additive for hydraulic composition prepared in (1), component (b) and component (c) shown in Table 1 were added to water so that the contents of components (a), (b) and (c) in the hydraulic composition were the values ​​shown in Table 1 to prepare mixing water. Next, fine aggregate, cement and fly ash were charged into a Hobart mixer according to JIS R 5201 so as to obtain the mixing amounts shown in Table 1, and dry-mixed at 140 rpm for 10 seconds. The mixing water was then added and the mixture was stirred for another 120 seconds to prepare a hydraulic composition slurry. The contents (parts by mass) of components (a), (b) and (c) in Table 1 are parts by mass calculated as the effective content relative to 100 parts by mass of hydraulic powder (total parts by mass of cement and fly ash). W / C is the ratio (% by mass) of water / hydraulic powder (total parts by mass of cement and fly ash).

[0064] (3) Evaluation of the effect of suppressing darkening of the hydraulic composition surface (2) 500mL of the hydraulic composition slurry prepared as above was weighed into a disposable cup, placed on a tapping table as described in JIS R 5201, and tapped 15 times, after which the surface of the hydraulic composition was photographed with a digital camera. The photographed image data was then subjected to image analysis using ImageJ, an open source image processing software, and the brightness was expressed in a histogram ranging from 0 to 255, and the standard deviation (StdDev) was used as an index of the blackening inhibition effect. The greater the variation between the white and black areas, the more blackening is visually recognized, so the smaller the standard deviation, the better the blackening inhibition effect is evaluated. The results are shown in Table 1.

[0065] [Table 1]

[0066] In Table 1, Examples 1 and 2 showed smaller standard deviations of the histograms, i.e., superior darkening suppression effects, compared to Comparative Examples 1 to 3. This is considered to be because, in the additive for hydraulic compositions added to the hydraulic composition, the neutralization degree (hydrophilicity / hydrophobicity) of the copolymer of component (a) was adjusted so that the pH at 25°C when the content of component (a) was 20 mass% was 9.0 or more and less than 11.0, and the copolymer effectively interacted with both the carbon component and the cement particles, thereby exhibiting an excellent darkening suppression effect.

Claims

1. An additive for a hydraulic composition, comprising a copolymer (hereinafter referred to as component (a)) containing a constituent monomer (a1) which is an olefin having 6 to 10 carbon atoms and a constituent monomer (a2) which is one or more unsaturated dibasic acids selected from maleic acid, fumaric acid, salts thereof, and maleic anhydride, wherein the molar ratio (a1) / (a2) of the constituent monomer (a1) to the constituent monomer (a2) in the constituent monomers is 4 / 6 or more and 6 / 4 or less, and the weight average molecular weight is 10,000 or more and 40,000 or less, and water, and when the content of component (a) is 20% by mass, the pH at 25°C is 9.0 or more and less than 11.

0.

2. The additive for a hydraulic composition according to claim 1, containing 5% by mass or more and 50% by mass or less of component (a).

3. The additive for a hydraulic composition according to claim 1 or 2, wherein the constituent monomer (a1) is an olefin having 8 carbon atoms.

4. The additive for a hydraulic composition according to claim 1 or 2, wherein the constituent monomer (a1) is diisobutylene.

5. The additive for a hydraulic composition according to claim 1 or 2, wherein the weight average molecular weight of component (a) is 20,000 or more and 30,000 or less.

6. A mixing agent composition for a hydraulic composition, containing the additive for a hydraulic composition according to claim 1 or 2 and (b) a polycarboxylic acid-based dispersant.

7. A hydraulic composition containing the additive for a hydraulic composition according to claim 1 or 2, (b) a polycarboxylic acid-based dispersant, hydraulic powder, and water.

8. A method for producing a hydraulic composition, comprising mixing the additive for a hydraulic composition according to claim 1 or 2, (b) a polycarboxylic acid-based dispersant (hereinafter referred to as component (b)), hydraulic powder, and water.

9. The method for producing a hydraulic composition according to claim 8, wherein the additive for the hydraulic composition and the component (b) are separately added to water to prepare a mixed water, and the mixed water and the hydraulic powder are mixed.