Additives for water hardening components

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 additives for hydraulic compositions, admixture compositions for hydraulic compositions, hydraulic compositions, and methods for producing the same. [Background technology]

[0002] In recent years, in order to achieve the SDGs, there has been a growing trend towards developing environmentally conscious infrastructure from an ESG perspective. Attempts have been made to partially replace cement with fly ash, an industrial by-product of coal-fired power generation, and to replace natural sand with crushed stone and sand obtained from rock crushing. However, fly ash contains unburned carbon remaining after incineration, and crushed stone and sand contain charcoal depending on their origin and type. When these are used as concrete materials, the carbon components appear on the concrete surface, impairing its aesthetic appeal and making the cleaning of formwork and other components more complicated.

[0003] Therefore, previous studies have attempted to reduce the aforementioned blackening by dispersing the carbon content using surfactants or polymers. Patent Document 1 discloses a concrete admixture containing one or more surfactants selected from nonionic surfactants having an HLB of 17.5 to 19.5 and 15 to 200 ethylene oxide groups per molecule, and anionic surfactants having 15 to 200 ethylene oxide groups per molecule. Patent Document 2 discloses an agent for inhibiting the deposition of black deposits on the surface of hardened concrete 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 hardened concrete by adding 0.0001 to 0.1 parts by weight of a copolymer of a monoolefin having 6 to 10 carbon atoms and maleic acid, or a salt thereof, in terms of solid content, to 100 parts by weight of cement. Patent Document 3 discloses an additive for preventing darkening of a cured hydraulic composition, which is composed of one or more 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 discloses a dispersant composed of a polymer composition obtained by mixing a second neutralizing agent made of an alkali metal hydroxide with a mixture of a composition containing a copolymer of an α-olefin and an unsaturated dibasic acid and water, and a first neutralizing agent made of an amine-type neutralizing agent, having a specific surface area of 500 to 2650 m 2 / g of a carbon material, and an aqueous medium, the aqueous slurry containing the same. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2002-234763 [Patent Document 2] Japanese Unexamined Patent Application Publication No. 2004-83303 [Patent Document 3] Japanese Unexamined Patent Application Publication No. 2005-213082 [Patent Document 4] Japanese Unexamined Patent Application Publication No. 2015-52029 [Summary of the Invention] [Problems to be Solved by the Invention]

[0005] However, existing concrete surface darkening inhibitors have a problem that the amount of addition required to obtain a sufficient darkening inhibitory effect is large. The present invention provides an additive for a hydraulic composition that is excellent in the effect of suppressing darkening that occurs on the surface of a cured hydraulic composition, an admixture composition for a hydraulic composition, a hydraulic composition in which darkening that occurs on the surface during curing is suppressed, and a method for producing the same. [Means for Solving the Problems]

[0006] The present invention relates to an additive for hydraulic compositions, comprising (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, salts thereof, and maleic anhydride, wherein the molecular ratio (a1) / (a2) of constituent monomer (a1) to constituent monomer (a2) in the constituent monomer 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, wherein the pH at 25°C is 9.0 or more and less than 11.0 when the content of component (a) is 20% by mass.

[0007] The present invention also relates to an admixture composition for hydraulic compositions containing 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 by mixing the additive for hydraulic compositions of the present invention, component (b), hydraulic powder, and water. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an additive for hydraulic compositions and an admixture composition for hydraulic compositions that are excellent in suppressing blackening that occurs on the surface of a hardened hydraulic composition, as well as a hydraulic composition in which blackening that occurs on the surface during hardening is suppressed, and a method for producing the same.

[0011] In recent years, the SDGs have been proposed to realize a sustainable society. This invention is considered to be a technology that can contribute to SDGs No. 7, 9, 11, 12, and 13, for example, by effectively utilizing industrial by-products and waste and reducing CO2 emissions. [Modes for carrying out the invention]

[0012] The inventors have found that when an additive for hydraulic compositions containing component (a) and water, and having a pH of 9.0 or higher and less than 11.0 at 25°C when component (a) is present at 20% by mass, is added to a hydraulic composition, it is excellent at suppressing the blackening that occurs on the surface of the hardened hydraulic composition. The reason for this effect is not entirely clear, but it is presumed to be as follows. The darkening in hydraulic compositions is thought to originate from trace amounts of carbon components. These carbon components are originally adsorbed onto fly ash, crushed stone, crushed sand, etc., and only after being dispersed by a cement dispersant does the difference in specific gravity in the slurry increase, causing them to separate from the hydraulic composition slurry and appear on the surface of the hardened material. When a copolymer of a hydrophobic olefin and an unsaturated dibasic acid, such as component (a) of the present invention, is added to the slurry of a hydraulic composition, it is thought that the hydrophobic olefin portion adsorbs onto the carbon components, and the carboxyl group of the unsaturated dibasic acid portion adsorbs onto the calcium catiosite on the surface of the cement particles, thereby tying the carbon components to the surface of the cement particles and suppressing the separation due to the aforementioned difference in specific gravity. However, if the carboxyl group of the unsaturated dibasic acid portion of the copolymer is completely neutralized, the hydrophilicity of the copolymer becomes excessively high, reducing its interaction force with the carbon components and consequently decreasing its darkening suppression effect. On the other hand, if the degree of neutralization of the carboxyl group in the unsaturated dibasic acid portion is low, the hydrophobicity of the copolymer becomes excessively high, making it difficult to retain the carbon component on the hydrophilic surface of the cement particles. 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. By adjusting the degree of neutralization (hydrophobicity) of the copolymer so that the pH at 25°C is 9.0 or higher and less than 11.0 when the content of component (a) is 20% by mass, it is considered that when added to a hydraulic composition, the copolymer effectively interacts with both the carbon component and the cement particles, resulting in an excellent blackening suppression effect.

[0013] [Additive for hydraulic composition] 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, salts thereof, and maleic anhydride, wherein the molar ratio (a1) / (a2) of constituent monomer (a1) to constituent monomer (a2) in the constituent monomer is 4 / 6 or more and 6 / 4 or less, and the copolymer has a weight-average molecular weight of 10,000 or more and 40,000 or less.

[0014] The constituent monomer (a1) is an olefin having 6 to 10 carbon atoms. The number of carbon atoms in 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 viewpoint of copolymerizability and blackening suppression effect. The constituent monomer (a1) can 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, their salts, and maleic anhydride. Examples of the aforementioned 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. The constituent monomer (a2) is preferably one or more selected from maleic anhydride and fumaric acid, and more preferably maleic anhydride, from the viewpoint of copolymerizability.

[0016] (a) Component may include, for example, a copolymer 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 suppression effect, a copolymer of diisobutylene and one or more selected from maleic anhydride, maleic acid, and fumaric acid is preferred.

[0017] (a) The weight-average molecular weight of component (by 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, and more preferably 30,000 or less, from the viewpoint of the handling properties of the aqueous solution and the effect of suppressing blackening. Component (a) can be produced, for example, by the method described in Japanese Patent Publication No. 55-40797. In this invention, the weight-average molecular weight of component (a) is the value converted to the unneutralized acid type compound.

[0018] (a) 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 , 9.0×105 (The numbers represent molecular weights)

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

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

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

[0022] The additive for hydraulic compositions of the present invention contains 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, and even more preferably 30% by mass or less, from the viewpoint of storage stability and handling of the aqueous solution. In this invention, the specification regarding the mass of component (a) shall be based on the value converted to the unneutralized acid-type 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 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, and even more preferably 85% by mass or less, from the viewpoint of storage stability and handling of aqueous solutions.

[0024] [Admixture composition for hydraulic compositions] The present invention provides an admixture composition for hydraulic compositions containing 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 component (a) by containing the additive for hydraulic compositions of the present invention. Component (a) is the same as the embodiment described for the additive for hydraulic compositions of the present invention. The admixture composition for hydraulic compositions of the present invention can be appropriately adapted to the embodiments described for the additive for hydraulic compositions of the present invention.

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

[0026] [ka]

[0027] [In the formula, R 1b , R 2b may be the same or different, and each represents a hydrogen atom or a methyl group R 3b : 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 added mole number of AO, which is a number of 1 to 300 p: a number of 0 to 2 q: 0 or 1 is shown.]

[0028]

Chemical formula

[0029] [In the formula, R 4b , R 5b , R 6b : may be the same or different, and each represents a hydrogen atom, a methyl group or (CH2) r COOM 1 , and (CH2) r COOM 1 may form an anhydride with COOM or another (CH2) r COOM 1 , in which case M, M of those groups 1 do not exist. M, M 1 : may be the same or different, and each represents 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 to 2 is shown.]

[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 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.

[0031] 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 improving the fluidity of the uncured hydraulic composition, 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, even more preferably 100 or less, and even more preferably 50 or less.

[0032] 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.

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

[0034] (b) Among the constituent monomers constituting component (b), the ratio of constituent monomer (b2) to the sum of constituent monomer (b1) and constituent monomer (b2) 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, even more preferably 60 mol% or more, even more preferably 70 mol% or more, and preferably 99 mol% or less, more preferably 90 mol% or less, and even more preferably 80 mol% or less.

[0035] (b) 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, even more preferably 100,000 or less, and even more preferably 50,000 or less, from the viewpoint of improving the fluidity of the uncured hydraulic composition. 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) In this invention, the weight-average molecular weight of component (b) shall be the value obtained by converting it to the value of the unneutralized acid-type compound.

[0036] (b) Specifically, the component is: (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 / methoxypolyethylene glycol copolymers, with (meth)acrylic acid referring 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.

[0037] The admixture composition for hydraulic compositions of the present invention may contain 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 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 hydraulic admixture composition of the present invention may contain 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 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 hydraulic admixture composition. In the present invention, the specification regarding the mass of component (b) shall be the value converted to the unneutralized acid type compound.

[0039] In the hydraulic admixture composition of the present invention, the mass ratio (b) / (a) of the content of component (a) to the content of 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 preferably 75 or less, more preferably 60 or less, and even more preferably 45 or less, from the viewpoint of suppressing blackening.

[0040] The hydraulic admixture composition of the present invention may contain water. When the hydraulic admixture composition of the present invention contains water, it preferably contains 50% by mass or more, more preferably 60% by mass or more, from the viewpoint of handling properties of the hydraulic admixture 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 an antifoaming agent as component (c) from the viewpoint of improving the strength of the hardened hydraulic composition and the fluidity of the unhardened hydraulic composition. Preferred defoaming agents include silicone-based defoaming agents, fatty acid ester-based defoaming agents, ether-based defoaming agents, and aliphatic amine-based defoaming agents. Dimethylpolysiloxane is more preferred among silicone-based defoaming agents, polyalkylene glycol fatty acid esters are more preferred among fatty acid ester-based defoaming agents, polyalkylene glycol alkyl ethers are more preferred among ether-based defoaming agents, and alkyldimethylamine or its salts are more preferred among aliphatic amine-based defoaming agents.

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

[0043] The admixture composition 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, a shrinkage reducing agent, a leavening agent, a water-soluble polymer, a surfactant, etc. (except for those corresponding to components (a), (b), and (c)).

[0044] [Method for producing admixture compositions for hydraulic compositions] The present invention provides a method for producing an admixture composition for hydraulic compositions, comprising mixing the additive for hydraulic compositions of the present invention with (b). Furthermore, the method for producing the admixture composition for hydraulic compositions of the present invention may involve further mixing in water. Furthermore, the method for producing the admixture composition for hydraulic compositions of the present invention may further involve mixing in the above-mentioned component (c).

[0045] The method for producing the admixture composition for hydraulic compositions of the present invention involves mixing the additive for hydraulic compositions of the present invention to mix component (a). Component (a) is the same as that described in the description of the additive for hydraulic compositions of the present invention. Furthermore, 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 hydraulic admixture composition of the present invention can be appropriately applied to the embodiments described in the hydraulic additive and hydraulic admixture of the present invention. In the method for producing the hydraulic admixture composition of the present invention, the mixing amounts of component (a), component (b), and component (c), and the mass ratio (b) / (a) can be applied by substituting the content of each component described in the hydraulic admixture 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-described component (c). The hydraulic composition of the present invention contains component (a) by containing the additive for hydraulic compositions of the present invention. Component (a) is the same as the embodiment described for the additive for hydraulic compositions of the present invention. Components (b) and (c) are the same as the embodiments described for the admixture composition for hydraulic compositions of the present invention. The hydraulic composition of the present invention can be appropriately adapted to the embodiments described in the additive for the hydraulic composition of the present invention, and the admixture composition for the hydraulic composition and its manufacturing method 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 include ordinary Portland cement, rapid-hardening Portland cement, ultra-rapid-hardening Portland cement, sulfate-resistant Portland cement, low-heat Portland cement, white Portland cement, and eco-cement (e.g., JIS R5214). Among these, from the viewpoint of shortening the time it takes for the hydraulic composition to reach the required strength, cement selected from rapid-hardening Portland cement, ordinary Portland cement, sulfate-resistant Portland cement, and white Portland cement is preferred, and cement selected from rapid-hardening Portland cement and ordinary Portland cement is more preferred.

[0048] Furthermore, the hydraulic powder may contain, in particular, a large amount of black fine powder, such as blast furnace slag, fly ash, silica fume, stone powder, calcium carbonate, and lignite, from the viewpoint of enjoying the effects of the present invention. As the hydraulic powder, blast furnace cement, fly ash cement, or silica fume cement, which are mixtures of cement with blast furnace slag, fly ash, silica fume, etc., may also be used.

[0049] The hydraulic composition of the present invention contains component (a) in an amount of 0.0001 parts by mass or more, more preferably 0.0005 parts by mass or more, even more preferably 0.001 parts by mass or more, and even more preferably 0.005 parts by mass or more, per 100 parts by mass of hydraulic powder, from the viewpoint of suppressing blackening, 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, even more preferably 0.05 parts by mass or less, and even more preferably 0.01 parts by mass or less.

[0050] The hydraulic composition of the present invention contains component (b) in an amount of 0.005 parts by mass or more, 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, per 100 parts by mass of hydraulic powder, from the viewpoint of the fluidity of the uncured hydraulic composition, and from the viewpoint of the strength development 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 component (a) to the content of 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 preferably 75 or less, more preferably 60 or less, and even more preferably 45 or less, from the viewpoint of suppressing blackening.

[0052] If the hydraulic composition of the present invention contains component (c), component (c) is preferably contained in an amount of 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 0.001 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, per 100 parts by mass of hydraulic powder.

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

[0054] The hydraulic composition of the present invention may contain aggregate. Examples of aggregate include fine aggregate and coarse aggregate. Examples of fine aggregate include those specified in JIS A 0203-2014, number 2311. Examples of fine aggregate include river sand, land sand, mountain sand, sea sand, lime sand, silica sand and their crushed forms, blast furnace slag fine aggregate, ferronickel slag fine aggregate, lightweight fine aggregate (artificial and natural), and recycled fine aggregate. Examples of coarse aggregate include those specified in JIS A 0203-2014, number 2312. For example, examples of coarse aggregate include river gravel, land gravel, mountain gravel, sea gravel, lime gravel, their crushed forms, blast furnace slag coarse aggregate, ferronickel slag coarse aggregate, lightweight coarse aggregate (artificial and natural), and recycled coarse aggregate. Different types of fine aggregate and coarse aggregate may be mixed, 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, and preferably 100% or less, more preferably 90% or less, and even more preferably 80% or less, from the viewpoint of developing the strength of the hydraulic composition, reducing the amount of hydraulic powder such as cement used, and improving the ability to fill into formwork, etc. The bulk volume is 1 m³ of concrete. 3 This is the ratio of the volume of coarse aggregate (including voids) inside. Furthermore, when the hydraulic composition is concrete, the amount of fine aggregate used is preferably 500 kg / m³ from the viewpoint of improving the ability to fill into formwork, etc. 3 Above, a comfortable 600 kg / m 3 More preferably 700 kg / m 3 The above is true, and preferably 1000 kg / m 3 More preferably 900 kg / m 3 The following applies: When the hydraulic composition is mortar, the amount of fine aggregate used is preferably 800 kg / m³. 3 In summary, a comfortable 900 kg / m 3 More preferably 1000 kg / m 3 The above is true, and preferably 2000 kg / m 3 More preferably, 1800 kg / m 3 More preferably, 1700 kg / m 3 The following applies:

[0056] The hardened material obtained from the hydraulic composition of the present invention has excellent effect in suppressing the darkening that occurs on the surface of the hardened material, and can therefore be used in structures and concrete products. Examples of structures include main parts such as columns, beams, floor slabs, and load-bearing walls of reinforced concrete and steel-reinforced concrete buildings, as well as civil engineering structures such as roads, bridges, bridge 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 concrete pipes.

[0057] [Method for producing a hydraulic composition] The present invention provides a method for producing a hydraulic composition by mixing the additive for hydraulic compositions of the present invention, component (b), hydraulic powder, and water. The method for producing the hydraulic composition of the present invention may further involve mixing in the above-mentioned component (c).

[0058] The method for producing the hydraulic composition of the present invention involves mixing the additive for the hydraulic composition of the present invention, thereby mixing component (a). Component (a) is the same as described in the description of the additive for the hydraulic composition of the present invention. Components (b) and (c) are the same as described in the description of the admixture composition for the hydraulic composition of the present invention. The method for producing the hydraulic composition of the present invention can appropriately apply the embodiments described in the additive for the hydraulic composition of the present invention, the admixture composition for the hydraulic composition of the present invention and its method for producing the same, and the hydraulic composition of the present invention. In the method for producing the hydraulic composition of the present invention, the mixing amounts of component (a), component (b), and component (c), and the mass ratio (b) / (a) can be applied by substituting the content of each component described in the hydraulic composition of the present invention with the mixing amounts.

[0059] A method for producing the hydraulic composition of the present invention includes separately adding the hydraulic composition additive of the present invention and component (b) to water to prepare mixed water, and then mixing the mixed water with the hydraulic powder. [Examples]

[0060] The materials used in the examples and comparative examples are shown below. <(a) Components> • (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: in general formula (b2), R 4b , R 6b is a hydrogen atom, R 5b(b2) is a constituent monomer in which is a methyl group and M is a hydrogen atom, MEPEG: in general formula (b1), R 1b , R 3b is a hydrogen atom, R 2b (b1) is a constituent monomer where is a methyl group, p is 0, q is 1, AO is an ethylene oxy 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): Defoaming agent (Defoaming agent No. 21, manufactured by Kao Corporation)

[0061] • Cement: Ordinary Portland cement (manufactured by Taiheiyo Cement Corporation, specific gravity 3.16) • Fly ash: JIS Class 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 additives for hydraulic compositions of the present invention Following the method described in Japanese Patent Publication No. 55-40797, component (a) listed in Table 1 and water were mixed, and a 48% aqueous sodium hydroxide solution (manufactured by Kanto Chemical Co., Ltd.) diluted with tap water was added to adjust the solid content concentration of component (a) to 20% by mass and the pH at 25°C to the value shown 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.). Hereafter, pH measurements were performed in the same manner for other examples and comparative examples.

[0063] Preparation of hydraulic composition slurry The additives for the hydraulic composition prepared in (1), component (b) and component (c) listed in Table 1 were added to water so that the content of components (a), (b), and (c) in the hydraulic composition was as shown in Table 1, and mixed to form the water. Next, fine aggregate, cement, and fly ash were added to a Hobart mixer as described in JIS R 5201 in the proportions shown in Table 1, and dry mixing was performed at 140 rpm for 10 seconds. Then, the mixed water was added and stirred for a further 120 seconds to prepare the hydraulic composition slurry. The content (parts by mass) of component (a), component (b), and component (c) in Table 1 is calculated as parts by mass of effective content per 100 parts by mass of hydraulic powder (total of parts by mass of cement and fly ash). W / C is the ratio (mass%) of water to hydraulic powder (total of parts by mass of cement and fly ash).

[0064] (3) Evaluation of the effect of suppressing blackening on the surface of the hydraulic composition 500 mL of the hydraulic composition slurry prepared as described in (2) was measured into a disposable cup, placed on a tapping table as described in JIS R 5201, and after 15 taps, the surface of the hydraulic composition was photographed with a digital camera. Subsequently, the captured image data was analyzed using the open-source image processing software ImageJ, and the brightness was represented as a histogram from 0 to 255. The standard deviation (StdDev) was used as an indicator of the darkening suppression effect. The greater the variation between white and black areas, the more darkening is perceived to be; therefore, the smaller the standard deviation, the better the darkening suppression effect is evaluated to be. The results are shown in Table 1.

[0065] [Table 1]

[0066] In Table 1, Examples 1 and 2 showed a smaller standard deviation in their histograms compared to Comparative Examples 1 and 3, indicating a superior blackening suppression effect. This is thought to be because the degree of neutralization (hydrophobicity) of the copolymer of component (a) was adjusted so that the pH at 25°C was between 9.0 and 11.0 when the content of component (a) was 20% by mass of the additive added to the hydraulic composition. As a result, the copolymer effectively interacted with both the carbon component and the cement particles, exhibiting a superior blackening suppression effect.

Claims

1. An additive for hydraulic compositions comprising (a) 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 constituent monomer (a1) to constituent monomer (a2) in the constituent monomer is 4 / 6 or more and 6 / 4 or less, and the weight-average molecular weight is 20,000 or more and 40,000 or less, and water, wherein the pH at 25°C measured when the content of component (a) is adjusted to 20% by mass is 9.0 or more and less than 11.

0.

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

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

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

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

6. An admixture composition for a hydraulic composition comprising (b) the additive for a hydraulic composition according to claim 1 or 2, and (b) a polycarboxylic acid-based dispersant.

7. The admixture composition for hydraulic compositions according to claim 6, wherein the mass ratio (b) / (a) of the content of component (a) to the content of component (b) in the admixture composition for hydraulic compositions is 20 or more and 75 or less.

8. A hydraulic composition comprising (b) an additive for hydraulic compositions according to claim 1 or 2, a polycarboxylic acid-based dispersant, a hydraulic powder, and water.

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

10. A method for producing a hydraulic composition according to claim 8, comprising separately adding the additive for the hydraulic composition and component (b) to water to prepare a mixed water, and then mixing the mixed water with the hydraulic powder.

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