Cement additive

Abstract

The purpose of the present invention is to provide a cement additive which can improve the strength of carbon dioxide gas fixation concrete. The present invention is a cement additive used in a cement composition for carbon dioxide fixation. The cement additive contains a compound represented by formula (1) and / or a polyamine compound (A1) which is a heterocyclic polyamine. (In the formula, R1, R2, R3, R4, R5 and R6 are the same or different, and represent a hydrogen atom or a hydrocarbon group having one or more carbon atoms; n and m are the same or different, and represent an integer of 0 or more; the number of nitrogen atoms included in formula (1) is 2-6; x1 and x2 are the same or different, and represent an integer of 0 or more; and P is the same or different, and represents a hydrogen atom or a structural unit having a separate amino group due to branching.)

Description

cement additives

[0001] The present invention relates to a cement additive, and more particularly to a cement additive used in a cement composition for carbon dioxide fixation.

[0002] CO emissions from the cement industry ２ The amount is the CO emitted by all industries ２ CO emissions from the cement industry account for about 8% of the total CO emissions. ２ Reducing the amount of CO is an important issue. ２ As one of the measures to reduce emissions, ２ and recovering the CO ２ Technology has been developed to produce concrete by injecting CO into cement. ２ The calcium carbonate reacts with the calcium component in the cement and is fixed as calcium carbonate, and the concrete obtained in this way has excellent strength, so the amount of cement used can be reduced compared to when producing regular concrete.

[0003] Regarding a technique for increasing the strength of concrete, Patent Document 1 discloses a cement additive containing a compound (A) having a weight-average molecular weight of more than 3000 and a structure in which 5 moles or more of alkylene oxide are added to 1 mole of polyhydric alcohol, and an alkanolamine compound (B). ２ In the technology for producing concrete by injecting a mixture of ammonium nitrate and ammonium hydroxide into cement, methods using various additives have been disclosed.

[0004] International Publication No. 2017 / 006995 International Publication No. 2024 / 030519

[0005] As mentioned above, concrete with immobilized carbon dioxide is stronger than regular concrete, but if the amount of cement used could be further reduced, carbon dioxide emissions could be further reduced, so there is a need for technology to further increase the strength of carbon dioxide immobilized concrete.

[0006] The present invention has been made in view of the above-mentioned current situation, and an object of the present invention is to provide a cement additive that can improve the strength of carbon dioxide fixation concrete.

[0007] The present inventors have conducted extensive research into cement additives that can be used in cement compositions for immobilizing carbon dioxide, and have found that a cement additive containing a polyamine compound with a specific structure improves the strength of carbon dioxide immobilizing concrete. This led to the realization that the above-mentioned problems can be solved in an excellent manner, and has thus arrived at the present invention.

[0008] The present invention includes the following cement additives, etc.: [1] A cement additive for use in a cement composition for fixation of carbon dioxide, the cement additive being represented by the following formula (1): (In the formula, R １ , R ２ , R ３ , R ４ , R ５ , R ６are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 or more carbon atoms. n and m are the same or different and represent an integer of 0 or greater. However, the number of nitrogen atoms contained in formula (1) is 2 to 6. x1 and x2 are the same or different and represent an integer of 0 or greater. P are the same or different and represent a hydrogen atom or a structural unit having another amino group due to branching. A cement additive comprising a compound represented by the formula (I) and / or a polyamine compound (A1) which is a heterocyclic polyamine. [2] The molecular weight of the polyamine compound (A1) is 50 to 1,000. [3] The cement additive according to [1] or [2] above, further comprising an alkanolamine compound (B) and / or an alkylene glycol-containing compound (C), wherein the compound (C) has a structure in which 5 moles or more of alkylene oxide are added to 1 mole of polyhydric alcohol or polyamine and has a weight-average molecular weight of greater than 3,000. [4] The alkanolamine compound (B) is at least one selected from the group consisting of monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, methylethanolamine, methylisopropanolamine, methyldiethanolamine, methyldiisopropanolamine, diethanolisopropanolamine, diisopropanolethanolamine, tetrahydroxyethylethylenediamine, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, and tris(2-hydroxybutyl)amine. The cement additive according to [3] above. [5] The cement additive according to [3] or [4] above, wherein the alkylene glycol-containing compound (C) is at least one selected from the group consisting of polyalkylene glycol, a polymer having a structural unit derived from a monomer in which an alkylene oxide is added to an unsaturated carboxylic acid, an alkylene oxide adduct of a polyhydric alcohol, a polymer having a structural unit derived from a monomer in which an alkylene oxide is added to an unsaturated alcohol, and an alkylene oxide adduct of an active hydrogen bonded to an amino group of a polyalkyleneimine.[6] The alkylene glycol-containing compound (C) is selected from the group consisting of polyethylene glycol, polypropylene glycol, polymers having structural units derived from alkylene oxide adducts of methacrylic acid, alkylene oxide adducts of sorbitol, alkylene oxide adducts of neopentyl glycol, alkylene oxide adducts of pentanediol, alkylene oxide adducts of butanediol, alkylene oxide adducts of glycerin, polymers having structural units derived from alkylene oxide adducts of vinyl alcohol, polymers having structural units derived from alkylene oxide adducts of allyl alcohol, alkylene oxide adducts of methallyl alcohol, and the like. The cement additive according to any one of [3] to [5] above, which is at least one selected from the group consisting of a polymer having structural units derived from a hydroxyl group adduct of butenyl alcohol, a polymer having structural units derived from an alkylene oxide adduct of 3-methyl-3-butenyl alcohol, a polymer having structural units derived from an alkylene oxide adduct of 3-methyl-2-butenyl alcohol, a polymer having structural units derived from an alkylene oxide adduct of 2-methyl-3-butenyl alcohol, and an alkylene oxide adduct of an active hydrogen bonded to an amino group of polyethyleneimine. [7] The cement additive according to any one of [3] to [6] above, wherein the total content of the alkanolamine compound (B) and the alkylene glycol-containing compound (C) is 1 to 500 mass% relative to 100 mass% of the polyamine compound (A1). [8] The cement additive according to any one of [3] to [7] above, wherein the content of the alkanolamine compound (B) is 0.5 to 250 mass% relative to 100 mass% of the polyamine compound (A1). [9] The cement additive according to any one of [3] to [8] above, wherein the content of the alkylene glycol-containing compound (C) is 0.5 to 250 mass% relative to 100 mass% of the polyamine compound (A1).

[10] A method for improving the strength of carbon dioxide immobilized concrete, the method comprising the step of adding a polyamine compound (A2) having two or more nitrogen atoms to a cement composition for carbon dioxide immobilization.

[11] The following formula (1): (In the formula, R １ , R ２ , R ３ , R ４ , R ５ , R ６ are the same or different and represent a hydrogen atom or a hydrocarbon group having one or more carbon atoms. n and m are the same or different and represent an integer of 0 or greater. However, the number of nitrogen atoms contained in formula (1) is 2 to 6. x1 and x2 are the same or different and represent an integer of 0 or greater. P is the same or different and represents a hydrogen atom, or a structural unit having another amino group due to branching. Concrete containing a compound represented by the formula (I) and / or a polyamine compound (A1) which is a heterocyclic polyamine, and in which 0.01 to 30 mass% of carbon dioxide is immobilized relative to 100 mass% of cement.

[12] A method for producing carbon dioxide-immobilized concrete, the production method comprising a step of mixing the cement additive according to any one of [1] to [9] above, cement, and carbon dioxide, wherein the mixing ratio of the carbon dioxide is 0.01 to 30 mass% relative to 100 mass% of cement.

[0009] The cement additive of the present invention has the above-mentioned constitution and can increase the strength of carbon dioxide fixation concrete, and therefore can be suitably used in cement compositions for carbon dioxide fixation, etc.

[0010] Preferred embodiments of the present invention will be specifically described below, but the present invention is not limited to the following description and can be appropriately modified and applied within the scope of the present invention. Note that a combination of two or more of the individual preferred embodiments of the present invention described below also falls within the scope of the present invention.

[0011] <Cement Additive> The cement additive of the present invention contains the compound represented by the above formula (1) and / or a polyamine compound (A1) that is a heterocyclic polyamine. By applying the cement additive of the present invention to a cement composition for immobilizing carbon dioxide, the immobilization of carbon dioxide is promoted by the polyamine compound (A1), and the immobilized carbon dioxide reacts with calcium ions eluted from the cement to produce calcium carbonate, which is expected to improve the strength of the concrete.

[0012] In the cement additive of the present invention, the content of the polyamine compound (A1) is not particularly limited, but is preferably 1 to 99 mass% relative to 100 mass% of the cement additive, more preferably 10 to 95 mass%, even more preferably 20 to 90 mass%, and particularly preferably 30 to 85 mass%.

[0013] The cement additive of the present invention preferably contains the alkanolamine compound (B) and / or the alkylene glycol-containing compound (C), thereby further improving the strength of concrete.

[0014] In the cement additive of the present invention, the content ratios of the alkanolamine compound (B) and the alkylene glycol-containing compound (C) are not particularly limited, but the total content ratio thereof is preferably 1 to 500 mass%, more preferably 5 to 400 mass%, even more preferably 10 to 300 mass%, and particularly preferably 15 to 200 mass%, relative to 100 mass% of the polyamine compound (A1).

[0015] In the cement additive of the present invention, the content of the alkanolamine compound (B) is not particularly limited, but is preferably 0.5 to 250 mass% relative to 100 mass% of the polyamine compound (A1), more preferably 2.5 to 200 mass%, even more preferably 5 to 150 mass%, and particularly preferably 7.5 to 100 mass%.

[0016] In the cement additive of the present invention, the content of the alkylene glycol-containing compound (C) is not particularly limited, but is preferably 0.5 to 250 mass% relative to 100 mass% of the polyamine compound (A1), more preferably 2.5 to 200 mass%, even more preferably 5 to 150 mass%, and particularly preferably 7.5 to 100 mass%.

[0017] The cement additive of the present invention may contain other components in addition to the polyamine compound (A1), the alkanolamine compound (B), and the alkylene glycol-containing compound (C). The content of the other components is not particularly limited, but is preferably 0 to 20% by mass relative to 100% by mass of the cement additive. It is more preferably 0 to 10% by mass, even more preferably 0 to 5% by mass, particularly preferably 0 to 1% by mass, and most preferably 0% by mass.

[0018] The polyamine compound (A1) in the cement additive is preferably used in a proportion of 0.001 to 10 mass % relative to 100 mass % of cement, more preferably 0.005 to 5 mass %, still more preferably 0.01 to 3 mass %, and particularly preferably 0.02 to 2 mass %.

[0019] The alkanolamine compound (B) is preferably used in an amount of 0.001 to 10 mass % relative to 100 mass % of cement, more preferably 0.005 to 5 mass %, even more preferably 0.01 to 3 mass %, and particularly preferably 0.02 to 2 mass %.

[0020] The alkylene glycol-containing compound (C) is preferably used in an amount of 0.001 to 10% by mass, more preferably 0.005 to 5% by mass, even more preferably 0.01 to 3% by mass, and particularly preferably 0.02 to 2% by mass, relative to 100% by mass of cement.

[0021] (Polyamine Compound (A1)) The polyamine compound (A1) is a compound represented by the above formula (1) and / or a heterocyclic polyamine. The polyamine compound (A1) used in the present invention may be one type of compound or two or more types of compounds.１ , R ２ , R ３ , R ４ , R ５ , R ６ are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 or more carbon atoms. The hydrocarbon group is not particularly limited, and examples thereof include aliphatic hydrocarbon groups such as alkyl groups, alkenyl groups, and alkynyl groups, alicyclic hydrocarbon groups such as cycloalkyl groups, and aromatic hydrocarbon groups such as aralkyl groups and aryl groups.

[0022] The hydrocarbon group preferably has 1 to 12 carbon atoms, more preferably 1 to 10 carbon atoms, even more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms.

[0023] Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group (amyl group), an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, an i-propyl group, a sec-butyl group, an i-butyl group, a t-butyl group, a 1-methylbutyl group, a 1-ethylpropyl group, a 2-methylbutyl group, an i-amyl group, a neopentyl group, a 1,2-dimethylpropyl group, a 1,1-dimethylpropyl group, a t-amyl group, a 1,3-dimethylbutyl group, a 3,3-dimethylbutyl group, a 2-ethylbutyl group, a 2- Examples of the alkyl groups include aliphatic alkyl groups such as ethyl-2-methylpropyl group, 1-methylheptyl group, 2-ethylhexyl group, 1,5-dimethylhexyl group, t-octyl group, branched nonyl group, decyl group, undecyl group, and dodecyl group; and alicyclic alkyl groups such as cyclopropyl group, cyclopropylmethyl group, cyclobutyl group, cyclobutylmethyl group, cyclopentyl group, cyclohexyl group, cyclohexylmethyl group, cycloheptyl group, cyclooctyl group, cyclohexylpropyl group, cyclododecyl group, norbornyl group (C7), adamantyl group (C10), and cyclopentylethyl group.

[0024] Examples of the alkenyl group include vinyl, allyl, 1-butenyl, 2-butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, and dodecenyl groups. Examples of the alkynyl group include ethynyl, 1-propynyl, 2-propynyl, butynyl, pentynyl, hexynyl, heptynyl, octynyl, nonynyl, decynyl, and dodecynyl groups.

[0025] Examples of the aryl group include a phenyl group, an o-, m-, or p-tolyl group, a 2,3-, or 2,4-xylyl group, a mesityl group, a naphthyl group, an anthryl group, a phenanthryl group, a biphenylyl group, etc. Examples of the aralkyl group include a benzyl group, a phenethyl group, a phenylpropyl group, a benzhydryl group, etc.

[0026] The hydrocarbon group is preferably an aliphatic hydrocarbon group, more preferably an alkyl group, still more preferably an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group, or a butyl group, and particularly preferably a methyl group or an ethyl group.

[0027] In the above formula (1), R １ , R ２ , R ３ , R ４ , R ５ , R ６ is a hydrogen atom is one of the preferred embodiments of the present invention.

[0028] In the above formula (1), P may be the same or different and is a hydrogen atom or a structural unit having another amino group by branching. An embodiment in which P is a hydrogen atom is one of the preferred embodiments of the present invention.

[0029] In the formula (1), n ​​and m are the same or different and are integers of 0 or more, provided that the number of nitrogen atoms contained in the formula (1) is 2 to 6. When the P is a hydrogen atom, the sum of n and m is 1 to 5.

[0030] In the above formula (1), n ​​-[CR １ ２ - (CR ２２ ) ｘ１ -N(R ３ ) )]-, and m occurrences of -[CR ４ ２ - (CR ５ ２ ) ｘ２ The —N(P)]— may be bonded in blocks or randomly.

[0031] In the above formula (1), x1 and x2 are the same or different and are integers of 0 or greater. x1 and x2 are preferably 0 to 5, more preferably 1 to 4, even more preferably 1 to 3, and particularly preferably 1 or 2.

[0032] Specific examples of the compound represented by the above formula (1) include polyalkylene polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, tetrabutylenepentamine, pentaethylenehexamine, 1,2-propanediamine (propylenediamine), and 1,3-propanediamine (trimethylenediamine); and polyalkylene imines such as polyethyleneimine.

[0033] The heterocyclic polyamine is not particularly limited as long as it is a heterocyclic compound having two or more amino groups, and examples thereof include piperazine, 2-methylpiperazine, imidazole, pyrazole, imidazoline, triazole, tetrazole, pyridazine, pyrimidine, pyrazine, benzimidazole, purine, benzotriazole, quinazoline, quinoxaline, cinnoline, pteridine, etc. Among these, heterocyclic compounds having two to four amino groups are preferred, heterocyclic compounds having two amino groups are more preferred, and piperazine and 2-methylpiperazine are even more preferred.

[0034] The polyamine compound (A1) is preferably a compound represented by formula (1), more preferably a polyalkylene polyamine or a polyalkylene imine, still more preferably a polyethylene polyamine, a polypropylene polyamine or a polyethylene imine, and particularly preferably ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine, 1,2-propane diamine (propylene diamine), or 1,3-propane diamine (trimethylene diamine) polyethylene imine.

[0035] The molecular weight of the polyamine compound (A1) is not particularly limited, but is preferably 50 to 1,000, more preferably 50 to 500, and even more preferably 50 to 300. When the polyamine compound (A1) is a polyalkyleneimine, the weight-average molecular weight is preferably less than 600, and more preferably less than 300. The weight-average molecular weight of the polyalkyleneimine can be measured by GPC analysis.

[0036] (Alkanolamine Compound (B)) The alkanolamine compound (B) may be any compound having an amino group and a hydroxyl group, and any appropriate alkanolamine compound may be used as long as the effects of the present invention are not impaired. Examples of such alkanolamine compounds (B) include low-molecular-weight alkanolamine compounds and high-molecular-weight alkanolamine compounds. The alkanolamine compound (B) used in the present invention may be one type of compound or two or more types of compounds.

[0037] Examples of low molecular weight alkanolamine compounds include primary alkanolamines such as monoethanolamine, monopropanolamine, monoisopropanolamine, and monobutanolamine; secondary alkanolamines such as diethanolamine, diisopropanolamine, N-methylethanolamine, N-ethylethanolamine, N-propylethanolamine, N-butylethanolamine, N-methylpropanolamine, N-methylisopropanolamine, N-ethylisopropanolamine, and N-propylisopropanolamine; triethanolamine, triisopropanolamine, and the like. amines, and tertiary alkanolamines such as N,N-dimethylethanolamine, N,N-dimethylpropanolamine, N,N-diethylethanolamine, N-ethyldiethanolamine, N-methyldiethanolamine, methyldiisopropanolamine, diethanolisopropanolamine, diisopropanolethanolamine, tetrahydroxyethylethylenediamine, N,N-bis(2-hydroxyethyl)2-propanolamine, N,N-bis(2-hydroxypropyl)-N-(hydroxyethyl)amine, N,N-bis(2-hydroxyethyl)-N-(2-hydroxypropyl)amine, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, and tris(2-hydroxybutyl)amine. Among these, preferred are monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, methylethanolamine, methylisopropanolamine, methyldiethanolamine, methyldiisopropanolamine, diethanolisopropanolamine, diisopropanolethanolamine, tetrahydroxyethylethylenediamine, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, and tris(2-hydroxybutyl)amine, and more preferred are triisopropanolamine, diisopropanolethanolamine, and N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine.Other low molecular weight alkanolamine compounds include, for example, monomers having a triisopropanolamine skeleton.

[0038] Examples of polymeric alkanolamine compounds include alkanolamines having a structure in which a portion of the alkanolamine is bonded to a polymer, such as a polymer having a triisopropanolamine skeleton.

[0039] (Alkylene glycol-containing compound (C)) The alkylene glycol-containing compound (C) (hereinafter also simply referred to as compound (C)) has a structure in which 5 moles or more of alkylene oxide are added to 1 mole of polyhydric alcohol or polyamine, and has a weight average molecular weight of more than 3000. The alkylene glycol-containing compound (C) used in the present invention may be one type of compound or two or more types of compounds.

[0040] The alkylene oxide is not particularly limited, and examples thereof include ethylene oxide, propylene oxide, butylene oxide, isobutylene oxide, 1-butene oxide, 2-butene oxide, and styrene oxide. Alkylene oxides having 2 to 10 carbon atoms are preferred, alkylene oxides having 2 to 8 carbon atoms are even more preferred, alkylene oxides having 2 to 6 carbon atoms are even more preferred, alkylene oxides having 2 to 4 carbon atoms are even more preferred, and alkylene oxides having 2 to 3 carbon atoms (i.e., ethylene oxide, propylene oxide) are even more preferred. Only one type of alkylene oxide may be used, or two or more types may be used.

[0041] The number of moles of alkylene oxide added per mole of the polyhydric alcohol or polyamine is not particularly limited as long as it is 5 or more, but is preferably 10 to 300, more preferably 15 to 250, and even more preferably 20 to 200. In one aspect, an embodiment in which the number of moles of alkylene oxide added per mole of the polyhydric alcohol or polyamine is 30 or more, 40 or more, or 50 or more is also one of the preferred embodiments of the present invention.

[0042] The weight average molecular weight of the compound (C) is preferably 4,000 to 1,000,000, more preferably 5,000 to 500,000, still more preferably 7,000 to 300,000, and particularly preferably 10,000 to 100,000. The weight average molecular weight can be measured by GPC.

[0043] The polyhydric alcohol is not particularly limited as long as it is a compound having two or more hydroxyl groups, and may be a low molecular weight compound, an oligomer, or a polymer. The polyhydric alcohol is preferably a dihydric to 500-hydric alcohol, more preferably a dihydric to 100-hydric alcohol, and even more preferably a trihydric to 50-hydric alcohol. Specific examples of polyhydric alcohols include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, neopentyl glycol, pentanediol, butanediol, glycerin, sorbitol, etc.; and those obtained by polymerizing a monomer having a hydroxyl group. Examples of the monomer having a hydroxyl group include unsaturated alcohols such as vinyl alcohol, allyl alcohol, methallyl alcohol, butenyl alcohol, 3-methyl-3-butenyl alcohol, 3-methyl-2-butenyl alcohol, and 2-methyl-3-butenyl alcohol. These may be polymerized alone or copolymerized with other polymerizable monomers.

[0044] The polyamine is not particularly limited as long as it is a compound having two or more amino groups having active hydrogen, and examples thereof include the above-mentioned polyalkylene polyamines and polyalkylene imines, etc. Among these, polyalkylene imines are preferred.

[0045] The compound (C) may have any appropriate functional group depending on the purpose. On the other hand, it is preferable that the compound (C) does not have a carboxyl group. When the compound (C) has such a configuration, the cement additive according to the embodiment of the present invention can more significantly improve the strength of the hardened product of the cement composition over a long period of time.

[0046] When the polyhydric alcohol is a polymer obtained by polymerizing a monomer having a hydroxyl group, examples of a method for obtaining compound (C) include a method in which a monomer having a hydroxyl group is polymerized and then an alkylene oxide is added; and a method in which an alkylene oxide is first added to a monomer having a hydroxyl group and then polymerized.

[0047] Specific examples of the compound (C) include polyethylene glycol, polypropylene glycol; polymers having structural units derived from polyalkylene glycol-containing monomers; alkylene oxide adducts of polyhydric alcohols; alkylene oxide adducts to active hydrogens bonded to amino groups of polyalkylene imines. These may be used alone or in combination of two or more. Examples of the polyalkylene glycol-containing monomer include unsaturated carboxylic acid monomers described below and monomers obtained by adding alkylene oxide to the unsaturated alcohols described above. The polymer having structural units derived from the polyalkylene glycol-containing monomer may also be a copolymer of the polyalkylene glycol-containing monomer and other monomers. Other monomers include unsaturated carboxylic acid monomers such as (meth)acrylic acid, maleic acid, and salts thereof; 3-(meth)allyloxy-2-hydroxypropanesulfonic acid, 2-(meth)allyloxyethylenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, p-styrenesulfonic acid, α-methyl-p-styrenesulfonic acid, vinylsulfonic acid, vinylsulfamic acid, (meth)allyl sulfonic acid, isoprene sulfonic acid, 4-(allyloxy)benzenesulfonic acid, 1-methyl-2-propene-1-sulfonic acid, 1,1-dimethyl-2-propene-1- Unsaturated sulfonic acids and salts thereof, such as sulfonic acid, 3-butene-1-sulfonic acid, 1-butene-3-sulfonic acid, 2-acrylamido-1-methylpropanesulfonic acid, 2-acrylamidopropanesulfonic acid, 2-acrylamido-n-butanesulfonic acid, 2-acrylamido-2-phenylpropanesulfonic acid, and 2-((meth)acryloyloxy)ethanesulfonic acid; hydroxyl group-containing ethers, such as 3-(meth)allyloxy-1,2-dihydroxypropane and 1-allyloxy-3-butoxypropan-2-ol; N-vinyl lactam monomers, such as N-vinylpyrrolidone;(Meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, iso-nonyl (meth)acrylate, dodecyl (meth)acrylate, and stearyl (meth)acrylate; hydroxyl group-containing (meth)acrylic acid esters such as hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxy-1-methylethyl (meth)acrylate, 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and hydroxypentyl (meth)acrylate; (meth)acrylamide, N-monomethyl (meth)acrylate, N-substituted or unsubstituted (meth)acrylamides such as styrene, α-methylstyrene, vinyltoluene, indene, vinylnaphthalene, phenylmaleimide, vinylaniline, and other vinyl aryl monomers; ethylene, propylene, butadiene, isobutylene, octene, and other alkenes; vinyl carboxylates such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, and butyl vinyl ether; vinyl ethylene carbonate and derivatives thereof; unsaturated amines such as N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylamide, vinylpyridine, vinylimidazole, and salts or quaternized products thereof; and vinyl cyanide monomers such as acrylonitrile and methacrylonitrile.

[0048] The compound (C) may be selected from the group consisting of polyethylene glycol, polypropylene glycol, polymers having structural units derived from an alkylene oxide adduct of methacrylic acid, alkylene oxide adducts of sorbitol, alkylene oxide adducts of neopentyl glycol, alkylene oxide adducts of pentanediol, alkylene oxide adducts of butanediol, alkylene oxide adducts of glycerin, polymers having structural units derived from an alkylene oxide adduct of vinyl alcohol, polymers having structural units derived from an alkylene oxide adduct of allyl alcohol, and alkylene oxide adducts of methallyl alcohol. A preferred embodiment of the invention is at least one selected from the group consisting of a polymer having structural units derived from an alkylene oxide adduct of butenyl alcohol, a polymer having structural units derived from an alkylene oxide adduct of 3-methyl-3-butenyl alcohol, a polymer having structural units derived from an alkylene oxide adduct of 3-methyl-2-butenyl alcohol, a polymer having structural units derived from an alkylene oxide adduct of 2-methyl-3-butenyl alcohol, and an alkylene oxide adduct of an active hydrogen bonded to an amino group of polyethyleneimine.

[0049] When the compound (C) is an alkylene oxide adduct to an active hydrogen bonded to an amino group of polyethyleneimine, the weight-average molecular weight of the alkylene oxide adduct to the active hydrogen bonded to the amino group of polyethyleneimine is preferably at least 10000. In this specification, the term "alkylene oxide adduct to an active hydrogen bonded to an amino group of polyethyleneimine" refers to an adduct in which an alkylene oxide (such as ethylene oxide) is added to the active hydrogen bonded to the amino group of polyethyleneimine in any appropriate number of moles.

[0050] When the compound (C) is a copolymer having a structural unit derived from an alkylene oxide adduct of 3-methyl-3-butenyl alcohol, it is preferable that the copolymer does not contain a carboxyl group or a salt thereof (e.g., an alkali metal salt or an alkaline earth metal salt), in order to further exhibit the effects of the present invention.

[0051] The cement additive of the present invention can increase the strength of carbon dioxide-immobilized concrete, and therefore can be suitably used in cement compositions for carbon dioxide immobilization. The present invention also relates to the use of the cement additive for cement compositions for carbon dioxide immobilization. The amount of carbon dioxide immobilized in concrete using the cement additive of the present invention is not particularly limited, but is preferably 0.01 to 30 mass% relative to 100 mass% of cement. This allows the strength of the concrete to be more sufficiently increased. The amount of carbon dioxide immobilized is more preferably 0.05 to 10 mass%, even more preferably 0.1 to 5 mass%, and particularly preferably 0.2 to 2 mass%.

[0052] <Cement composition for fixing carbon dioxide> The cement composition for fixing carbon dioxide in which the cement additive of the present invention is used is fresh concrete containing cement, water, and aggregate. The cement composition for fixing carbon dioxide containing the cement additive of the present invention, cement, water, and aggregate also constitutes one aspect of the present invention.

[0053] The content of the polyamine compound (A1) in the cement composition for carbon dioxide fixation is not particularly limited, but is preferably 0.001 to 10 mass% relative to 100 mass% of cement, more preferably 0.005 to 5 mass%, even more preferably 0.01 to 3 mass%, and particularly preferably 0.02 to 2 mass%.

[0054] The cement additive preferably contains the alkanolamine compound (B) and / or the alkylene glycol-containing compound (C), and the total content of the alkanolamine compound (B) and the alkylene glycol-containing compound (C) in the carbon dioxide fixation cement composition is preferably 0.001 to 10 mass% relative to 100 mass% of cement. It is more preferably 0.005 to 5 mass%, even more preferably 0.01 to 3 mass%, and particularly preferably 0.02 to 2 mass%. In the carbon dioxide fixation cement composition, the content of the alkanolamine compound (B) and the alkylene glycol-containing compound (C) may be 0 mass%.

[0055] The content of the alkanolamine compound (B) in the carbon dioxide fixation cement composition is not particularly limited, but is preferably 0.001 to 10 mass% relative to 100 mass% of cement, more preferably 0.005 to 5 mass%, even more preferably 0.01 to 3 mass%, and particularly preferably 0.02 to 2 mass%.

[0056] The content of the alkylene glycol-containing compound (C) in the carbon dioxide fixation cement composition is not particularly limited, but is preferably 0.001 to 10 mass% relative to 100 mass% of cement, more preferably 0.005 to 5 mass%, even more preferably 0.01 to 3 mass%, and particularly preferably 0.02 to 2 mass%.

[0057] The cement used in the carbon dioxide fixation cement composition is not particularly limited, but may be Portland cement (normal, early strength, extra early strength, moderate heat, sulfate resistant, and their respective low alkali forms); various blended cements (blast furnace cement, silica cement, fly ash cement, calcium carbonate blended cement, limestone burned clay cement (LC3)); white Portland cement; alumina cement; ultra-rapid hardening cement (1 clinker rapid hardening cement, 2 clinker rapid hardening cement, magnesium phosphate cement, etc.); ); grout cement; oil well cement; low-heat cement (low-heat blast furnace cement, low-heat blast furnace cement mixed with fly ash, belite-rich cement); ultra-high-strength cement; cement-based solidification material; ecocement (cement produced using one or more of municipal waste incineration ash and sewage sludge incineration ash as raw materials), as well as those obtained by adding gypsum or fine powders such as blast furnace slag, fly ash, cinder ash, clinker ash, husk ash, silica fume, silica powder, and limestone powder to these. The above cements may be of only one type, or of two or more types.

[0058] The aggregate used in the carbon dioxide fixation cement composition is not particularly limited, but examples thereof include gravel, crushed stone, granulated slag, recycled aggregate, and the like, as well as refractory aggregate such as silica stone, clay, zircon, high alumina, silicon carbide, graphite, chromium, chromium-magnesium, and magnesia.

[0059] In the carbon dioxide fixation cement composition, ３ The unit water amount, cement amount used, and water / cement ratio per unit are not particularly limited, but preferably, the unit water amount is 100 kg / m ３ ~185 kg / m ３ The cement usage is 250 kg / m ３ ~800 kg / m ３ and the water / cement ratio (mass ratio) is 0.1 to 0.7, and more preferably, the unit water content is 120 kg / m ３ ~180 kg / m ３ The cement usage is 270 kg / m ３ ~800 kg / m ３and the water / cement ratio (mass ratio) is 0.12 to 0.65.

[0060] The carbon dioxide fixation cement composition may further contain other commonly used cement dispersants and water-reducing agents, and a combination of these may be used. The other cement dispersants (water-reducing agents) are not particularly limited, and examples thereof include various polycarboxylic acid dispersants (water-reducing agents) having a polyoxyalkylene chain and a carboxyl group in the molecule, various sulfonic acid dispersants (water-reducing agents) having a sulfonic acid group in the molecule, and various phosphate dispersants (water-reducing agents) having a phosphate group in the molecule.

[0061] The polycarboxylic acid dispersant (water-reducing agent) is preferably a polymer obtained by copolymerizing a monomer component containing an unsaturated carboxylic acid monomer and a (poly)alkylene glycol monomer. The unsaturated carboxylic acid monomer is not particularly limited, and examples thereof include the same monomers as the unsaturated carboxylic acid monomers described above. Specific examples of the (poly)alkylene glycol monomer include compounds in which 1 to 300 moles of alkylene oxide are added to an unsaturated alcohol having 2 to 8 carbon atoms, and terminally hydrophobically modified products thereof, as well as esters of unsaturated carboxylic acid monomers and (poly)alkylene glycols having an average added mole number of 1 to 300, and terminally hydrophobically modified products thereof.

[0062] The polycarboxylic acid dispersant (water reducing agent) preferably has a proportion of structural units derived from unsaturated carboxylic acid monomers of less than 35% by mass relative to 100% by mass of all structural units. This proportion is more preferably 1 to 30% by mass, and even more preferably 1 to 25% by mass. The polycarboxylic acid dispersant (water reducing agent) preferably has a proportion of structural units derived from (poly)alkylene glycol monomers of 65% by mass or more relative to 100% by mass of all structural units. This proportion is more preferably 70 to 99% by mass, and even more preferably 75 to 99% by mass. The polycarboxylic acid dispersant (water reducing agent) preferably has a weight average molecular weight of 5,000 to 500,000. This proportion is more preferably 7,000 to 200,000, even more preferably 8,000 to 100,000, and particularly preferably 10,000 to 50,000.

[0063] The sulfonic acid-based dispersant (water-reducing agent) is not particularly limited, and examples thereof include polyalkylarylsulfonate-based dispersants such as naphthalenesulfonic acid formaldehyde condensates; melamine formalin resin sulfonate-based dispersants such as melamine sulfonic acid formaldehyde condensates; aromatic aminosulfonate-based dispersants such as aminoarylsulfonic acid-phenol-formaldehyde condensates; lignin sulfonate-based dispersants such as lignin sulfonates and modified lignin sulfonates; and various sulfonic acid-based dispersants having a sulfonic acid group in the molecule, such as polystyrene sulfonate-based dispersants.

[0064] Examples of the phosphoric acid-based dispersant (water-reducing agent) include various phosphoric acid ester-based dispersants having a (poly)oxyalkylene group and a phosphoric acid group in the molecule, such as copolymers obtained from (alkoxy)polyalkylene glycol mono(meth)acrylates, phosphoric acid monoester monomers, and phosphoric acid diester monomers, as described in JP-A-2006-52381; and aromatic compound polycondensation-type phosphoric acid-based dispersants having a (poly)oxyalkylene group and a phosphoric acid group, as described in JP-A-2008-517080.

[0065] The cement dispersant (water reducing agent) may be of one type or of two or more types. The content of the cement dispersant (water reducing agent) is not particularly limited, but is preferably 0 to 5 mass %, more preferably 0.01 to 0.5 mass %, and particularly preferably 0.05 to 0.3 mass %, relative to 100 mass % of cement.

[0066] The content of the cement dispersant (water reducing agent) is preferably 5 to 2000% by mass, more preferably 10 to 1000% by mass, and even more preferably 30 to 700% by mass, relative to 100% by mass of the polyamine compound (A1).

[0067] The carbon dioxide fixation cement composition may further contain other additives. Examples of the other additives include cement additives (materials) exemplified by the following (1) to (12), cement wetting agents, thickeners, separation-reducing agents, flocculants, drying shrinkage-reducing agents, strength enhancers, self-leveling agents, rust inhibitors, colorants, and antifungal agents. One or more of these may be used.

[0068] (1) Water-soluble polymeric substances: nonionic cellulose ethers such as methyl cellulose, ethyl cellulose, carboxymethyl cellulose, etc.; polysaccharides produced by microbial fermentation such as yeast glucan, xanthan gum, and β-1,3 glucans; polyacrylamide, etc. (2) Polymer emulsions: copolymers of various vinyl monomers such as alkyl (meth)acrylate, etc. (3) Set retarders: oxycarboxylic acids or their salts such as gluconic acid, glucoheptonic acid, arabinonic acid, malic acid, citric acid, etc.; sugars and sugar alcohols; polyhydric alcohols such as glycerin; phosphonic acids and their derivatives such as aminotri(methylenephosphonic acid), etc. (4) Early-strengthening agents / accelerators: soluble calcium salts such as calcium chloride, calcium nitrite, calcium nitrate, calcium bromide, calcium iodide, etc.; chlorides such as iron chloride and magnesium chloride; sulfates; potassium hydroxide; sodium hydroxide; carbonates; thiosulfates; formates such as formic acid and calcium formate; alumina cement; calcium aluminate silicate, etc. (5) Oxyalkylene-based defoaming agents: polyoxyalkylene alkyl ethers such as diethylene glycol heptyl ether; polyoxyalkylene acetylene ethers; (poly)oxyalkylene fatty acid esters; polyoxyalkylene sorbitan fatty acid esters; polyoxyalkylene alkyl (aryl) ether sulfate ester salts; polyoxyalkylene alkyl phosphate esters; polyoxypropylene polyoxyethylene laurylamine (1 to 20 moles of propylene oxide added, 1 to 20 moles of ethylene oxide added, etc.), polyoxyalkylene alkylamines such as amines derived from fatty acids obtained from hardened beef tallow to which alkylene oxide has been added (1 to 20 moles of propylene oxide added, 1 to 20 moles of ethylene oxide added, etc.); polyoxyalkylene amides, etc. (6) Non-oxyalkylene-based defoaming agents: mineral oil-based, oil-based, fatty acid-based, fatty acid ester-based, alcohol-based, amide-based, phosphate ester-based, metal soap-based, silicone-based, etc. defoaming agents.

[0069] (7) Air-Entraining Agents: Resin soaps, saturated or unsaturated fatty acids, sodium hydroxystearate, lauryl sulfate, ABS (alkylbenzene sulfonic acid), alkanesulfonates, polyoxyethylene alkyl(phenyl) ethers, polyoxyethylene alkyl(phenyl) ether sulfates or their salts, polyoxyethylene alkyl(phenyl) ether phosphates or their salts, protein materials, alkenyl sulfosuccinate, α-olefin sulfonates, etc. (8) Other Surfactants: Various anionic surfactants; Various cationic surfactants such as alkyltrimethylammonium chloride; Various nonionic surfactants; Various amphoteric surfactants, etc. (9) Waterproofing Agents: Fatty acids (salts), fatty acid esters, oils and fats, silicone, paraffin, asphalt, wax, etc. (10) Rust Inhibitors: Nitrites, phosphates, zinc oxide, etc. (11) Crack Reducers: Polyoxyalkyl ethers, etc. (12) Expansive Agents: Ettringite-based, coal-based, etc.

[0070] The content of the other additives is not particularly limited, but is preferably 0 to 5 mass % relative to 100 mass % of cement, more preferably 0 to 1.25 mass %, and particularly preferably 0 to 0.075 mass %.

[0071] <Carbon dioxide immobilized concrete> The present invention also relates to concrete containing a polyamine compound (A1) and immobilizing 0.01 to 30% by mass of carbon dioxide relative to 100% by mass of cement. The amount of carbon dioxide immobilized in the concrete is more preferably 0.05 to 10% by mass, even more preferably 0.1 to 5% by mass, and particularly preferably 0.2 to 1% by mass, relative to 100% by mass of cement.

[0072] The content ratio of the polyamine compound (A1) in the carbon dioxide fixation concrete is as described above in the carbon dioxide fixation cement composition. The carbon dioxide fixation concrete preferably contains the alkanolamine compound (B) and / or the alkylene glycol-containing compound (C), and specific examples, preferred forms, and content ratios thereof are as described above. The carbon dioxide fixation concrete contains cement and aggregate, and may also contain fine aggregate (sand, etc.), coarse aggregate (crushed stone, etc.), and other additives. Specific examples and content ratios thereof are as described above.

[0073] <Method for producing carbon dioxide-immobilized concrete> The present invention also relates to a method for producing carbon dioxide-immobilized concrete, which includes a step of mixing the cement additive of the present invention, cement, and carbon dioxide (hereinafter also referred to as a mixing step), in which the mixing ratio of the carbon dioxide is 0.01 to 30 mass% relative to 100 mass% of cement. The cement additive used in the mixing step is as described in the cement additive of the present invention.

[0074] The mixing step is not particularly limited as long as the cement additive, cement, and carbon dioxide are mixed so that the carbon dioxide mixing ratio falls within the above range. The carbon dioxide mixing ratio is more preferably 0.05 to 10 mass %, even more preferably 0.1 to 5 mass %, and particularly preferably 0.2 to 1 mass %, relative to 100 mass % of cement.

[0075] The mixing ratio of the cement additive in the mixing step is not particularly limited, but it is preferable to mix the polyamine compound (A1) so that the ratio is 0.001 to 10 mass% relative to 100 mass% of cement, more preferably 0.005 to 5 mass%, even more preferably 0.01 to 3 mass%, and particularly preferably 0.02 to 2 mass%.

[0076] The cement additive preferably contains the alkanolamine compound (B) and / or the alkylene glycol-containing compound (C), and the mixing ratio thereof is preferably the same as the ratio in the cement composition for carbon dioxide fixation.

[0077] In the mixing step, the order in which the cement additive, cement, and carbon dioxide are mixed is not particularly limited, and they may be added all at once to a mixer or the like and mixed, or they may be added sequentially and mixed. For example, the cement additive and cement may be mixed and then carbon dioxide may be mixed, or the cement and carbon dioxide may be mixed and then the cement additive may be mixed, or the cement additive and carbon dioxide may be mixed in water and then the cement may be mixed, or the cement additive, cement, and carbon dioxide may be mixed simultaneously. Preferably, the cement additive and cement are mixed and then carbon dioxide is mixed.

[0078] The form of carbon dioxide used in the mixing step is not particularly limited, and may be any of gas, liquid, and solid, or may be dissolved in water or the like to form carbonate ions. Carbon dioxide is preferably in the form of solid or liquid. Mixing liquid or solid carbon dioxide into a composition containing the cement additive and cement is one of the preferred embodiments of the present invention.

[0079] The temperature in the mixing step is not particularly limited, but is preferably 0 to 60° C., and more preferably 5 to 40° C. This allows the carbon dioxide to be mixed more thoroughly into the cement composition.

[0080] In the mixing step, fine aggregate, coarse aggregate, and other additives may be further mixed in. Specific examples and content ratios of the other additives are as described above.

[0081] <Method for Improving Strength of Carbon Dioxide-Immobilized Concrete> The present invention also relates to a method for improving the strength of carbon dioxide-immobilized concrete, which includes a step of adding a polyamine compound (A2) having two or more nitrogen atoms to a cement composition for immobilizing carbon dioxide (hereinafter also referred to as an adding step). In the adding step, the timing of adding the cement additive is not particularly limited, as long as the polyamine compound (A2) is added to the cement composition for immobilizing carbon dioxide. The adding step may be before, after, or simultaneously with the addition of carbon dioxide to the cement composition for immobilizing carbon dioxide. Preferably, the cement additive is added before the addition of carbon dioxide.

[0082] The amount of the polyamine compound (A2) added in the adding step is not particularly limited, but is preferably added so as to be 0.001 to 10% by mass, more preferably 0.005 to 5% by mass, even more preferably 0.01 to 3% by mass, and particularly preferably 0.02 to 2% by mass, relative to 100% by mass of cement.

[0083] In the above-mentioned addition step, it is preferable to further add an alkanolamine compound (B) and / or an alkylene glycol-containing compound (C). The total amount of the alkanolamine compound (B) and / or the alkylene glycol-containing compound (C) added is preferably 0.001 to 10 mass% relative to 100 mass% of cement, more preferably 0.005 to 5 mass%, even more preferably 0.01 to 3 mass%, and particularly preferably 0.02 to 2 mass% relative to 100 mass% of cement.

[0084] The amount of alkanolamine compound (B) added in the above-mentioned addition step is preferably 0.001 to 10 mass% relative to 100 mass% of cement, more preferably 0.005 to 5 mass% relative to 100 mass% of cement, even more preferably 0.01 to 3 mass%, and particularly preferably 0.02 to 2 mass%. The amount of alkylene glycol-containing compound (C) added in the above-mentioned addition step is preferably 0.001 to 10 mass% relative to 100 mass% of cement, more preferably 0.005 to 5 mass% relative to 100 mass% of cement, even more preferably 0.01 to 3 mass%, and particularly preferably 0.02 to 2 mass%.

[0085] The carbon dioxide fixation cement composition contains cement and aggregate. The carbon dioxide fixation cement composition may also contain fine aggregate, coarse aggregate, and other additives. Specific examples and content ratios of the other additives are as described above.

[0086] (Polyamine Compound (A2)) The polyamine compound (A2) is not particularly limited as long as it is an amine compound having two or more nitrogen atoms, and may be a compound having two or more nitrogen atom-containing groups selected from the group consisting of a primary amino group, a secondary amino group, a tertiary amino group, a quaternary ammonium group, and an imino group. The polyamine compound (A2) is preferably a compound represented by the following formula (1') or (2):

[0087]

[0088] (In the formula, R １ , R ２ , R ３ , R ４ , R ５ , R ６ , R ７ , R ８ , R ９ , R １０ , R １１are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 or more carbon atoms. n' and m' are the same or different and represent an integer of 0 or more. However, the number of nitrogen atoms contained in formula (1') or (2) is 2 or more. x1, x2, and x3 are the same or different and represent an integer of 0 or more. P is the same or different and represents a hydrogen atom or a structural unit having another amino group due to branching. 1 is an integer of 2 or more. The compound is at least one selected from the group consisting of compounds represented by the formula (I) and heterocyclic polyamines.

[0089] Specific examples and preferred embodiments of the heterocyclic polyamine are the same as those of the heterocyclic polyamine in the cement additive.

[0090] R in the above formula (1′) １ ~R ６ Specific examples and preferred embodiments of x1, x2, and P are the same as those of formula (1) in the cement additive. ７ , R ８ are the same or different and are a hydrogen atom or a hydrocarbon group having one or more carbon atoms. Specific examples and preferred embodiments of the hydrocarbon group are １ ~R ６ is the same as:

[0091] In the above formula (1'), n' and m' may be the same or different and are an integer of 0 or greater, provided that the number of nitrogen atoms contained in the polyamine compound (A2) is 2 or greater. The number of nitrogen atoms contained in the polyamine compound (A2) is preferably 2 to 1,000, more preferably 2 to 100, even more preferably 2 to 30, and particularly preferably 2 to 6.

[0092] In the above formula (1′), n′ structural units —[CR １ ２ - (CR ２ ２ ) ｘ１ -N(R ３ ) )]-, and m' structural units -[CR ４ ２ - (CR ５ ２ ) ｘ２ The —N(P)]— may be bonded in blocks or randomly.

[0093] Specific examples of the compound represented by formula (1') include polyalkylene polyamines such as ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine, 1,2-propane diamine (propylene diamine), 1,3-propane diamine (trimethylene diamine), and hexaethylene heptamine; polyalkylene imines such as polyethylene imine; and N-alkyl polyalkylene polyamines such as N,N,N',N'-tetramethyl ethylene diamine and N,N,N',N'',N''-pentamethyl diethylene triamine. The preferred form of the compound represented by formula (1') is the same as that of the compound represented by formula (1).

[0094] R in the above formula (2) ９ , R １０ , R １１ are the same or different and are a hydrogen atom or a hydrocarbon group having one or more carbon atoms. Specific examples of the hydrocarbon group include R １ ~R ６ The hydrocarbon group in the above R ９ , R １０ , R １１ is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and more preferably a hydrogen atom or a methyl group. ９ , R １０ , R １１ An embodiment in which is a hydrogen atom is also one of the preferred embodiments of the present invention.

[0095] In the above formula (2), x3 is an integer of 0 or more, preferably 0 to 5, more preferably 0 to 3, still more preferably 0 to 2, and particularly preferably 0 or 1.

[0096] In the above formula (2), l is an integer of 2 or more, preferably 2 to 1000, more preferably 2 to 500, even more preferably 2 to 100, and particularly preferably 2 to 50.

[0097] Specific examples of the compound represented by the formula (2) include polymers of unsaturated amines such as polyvinylamine and polyallylamine.

[0098] The polyamine compound (A2) is preferably a compound represented by formula (1), more preferably a polyalkylene polyamine or a polyalkylene imine, still more preferably a polyethylene polyamine, a polypropylene polyamine or a polyethylene imine, and particularly preferably ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine, 1,2-propane diamine (propylene diamine), 1,3-propane diamine (trimethylene diamine) or a polyethylene imine.

[0099] The molecular weight of the polyamine compound (A2) is not particularly limited, but is preferably 50 to 1,000, more preferably 50 to 500, and even more preferably 50 to 300. When the polyamine compound (A2) is a compound represented by formula (2), the weight-average molecular weight is preferably 1,000,000 or less, more preferably 600 to 100,000, and even more preferably 600 to 10,000. The weight-average molecular weights of the polyalkyleneimine and the compound represented by formula (2) can be measured by GPC analysis.

[0100] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" means "parts by weight" and "%" means "% by mass."

[0101] <Preparation of Water-Reducing Admixture> [Production Example 1]: Production of Polymer (1) A glass reaction vessel equipped with a Dimroth condenser, a stirrer equipped with a Teflon (registered trademark) stirring blade and stirring seal, a nitrogen inlet tube, and a temperature sensor was charged with 198.2 parts of a compound obtained by adding ethylene oxide to the hydroxyl groups of 3-methyl-3-buten-1-ol (isoprenol) (average number of moles of ethylene oxide added: 50) (hereinafter referred to as IPN-50) (80% aqueous solution), 0.32 parts of acrylic acid, 12.47 parts of aqueous hydrogen peroxide (2% aqueous solution), and 44.75 parts of ion-exchanged water, and the mixture was heated to 58°C while stirring at 250 rpm and introducing nitrogen at a rate of 200 mL / min. Next, a mixed solution consisting of 27.12 parts of acrylic acid and 108.5 parts of ion-exchanged water was added dropwise over 3 hours, and simultaneously, a mixed solution consisting of 0.74 parts of L-ascorbic acid, 6.61 parts of 3-mercaptopropionic acid, and 86.31 parts of ion-exchanged water was added dropwise over 3 hours and 30 minutes. After completion of the dropwise addition, the temperature was maintained at 58°C for 1 hour to complete the polymerization reaction. Then, the mixture was neutralized with an aqueous sodium hydroxide solution to obtain an aqueous solution of polymer (1) having a weight average molecular weight of 30,000.

[0102] [Production Example 2]: Production of Polymer (2) 80.0 parts of ion-exchanged water was charged into a glass reaction vessel equipped with a Dimroth condenser, a Teflon (registered trademark) stirring blade and stirring seal stirrer, a nitrogen inlet tube, and a temperature sensor, and heated to 70 ° C. while stirring at 250 rpm and introducing nitrogen at 200 mL / min. Next, a mixed solution of 133.4 parts of methoxypolyethylene glycol monomethacrylate ester (average number of moles of ethylene oxide added: 9), 26.6 parts of methacrylic acid, 6.53 parts of mercaptopropionic acid, and 106.7 parts of ion-exchanged water was added dropwise over 4 hours, and simultaneously a mixed solution of 1.19 parts of ammonium persulfate and 50.6 parts of ion-exchanged water was added dropwise over 5 hours. After completion of the dropwise addition, the temperature was maintained at 70 ° C. for 1 hour to complete the polymerization reaction. Then, the mixture was neutralized with aqueous sodium hydroxide solution to obtain an aqueous solution of polymer (2) having a weight average molecular weight of 25,000.

[0103] [Production Example 3]: Production of Polymer (3) A condensation reaction was carried out in accordance with the method described in JP-A No. 2008-517080, and polyethylene glycol (average number of moles of ethylene oxide added: 20 moles) monophenyl ether and phenoxyethanol phosphate were condensed with formaldehyde to obtain an aqueous solution of Polymer (3), which is a phosphoric acid-based dispersant containing a condensate of polyethylene glycol (average number of moles of ethylene oxide added: 20 moles) monophenyl ether and phenoxyethanol phosphate in a ratio of 30 / 70 (mol %) and having a weight-average molecular weight (Mw) of 25,000.

[0104] [Production Example 4]: Production of polymer (4) A copolymerization reaction was carried out in accordance with the method described in JP-A No. 2004-519406, to obtain an aqueous solution of polymer (4) having a weight average molecular weight (Mw) of 32,000 and a copolymer composition ratio of unsaturated polyalkylene glycol ether in which an average of 50 moles of ethylene oxide was added to methallyl alcohol and sodium acrylate of 85 / 15 (mass %) and 19 / 81 (mol %).

[0105] [Production Example 5]: Preparation of Dispersant (5) Mighty 150 (manufactured by Kao Corporation) was used as dispersant (5).

[0106] Preparation Example 6: Preparation of Dispersant (6) Master Pozzolith No. 8 (manufactured by Pozzolith Solutions) was used as dispersant (6).

[0107] <Alkanolamine Compound (B)> TIPA (triisopropanolamine, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) DIPA (diisopropanolamine, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0108] <Alkylene glycol-containing compound (C)> PEG6000 (polyethylene glycol, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., weight average molecular weight = 6000) ESP (weight average molecular weight = 23000, polyethyleneimine (weight average molecular weight = 600) in which 20 moles of ethylene oxide are added to 1 mole of active hydrogen of the amino group)

[0109] <Mortar Test> (Mortar Mixture) The mortar mix used in this example is any one of mixes (1) to (4) shown in Table 1 below. C: Ordinary Portland cement (manufactured by Taiheiyo Cement Corporation) S: Mountain sand W: Ion-exchanged water (containing cement additives, water-reducing agent, and antifoaming agent) D: Dry ice (manufactured by Amax Corporation)

[0110]

[0111] (Mortar Preparation Procedure) The experimental environment was 20°C ± 1°C and humidity 60% ± 10%. A predetermined amount of aqueous solution of cement additives and water-reducing agent was weighed out, and ADEKA NOL LG-299 (manufactured by ADEKA CORPORATION) was added as an antifoaming agent at 0.02 mass% solids relative to the cement. Deionized water was then added to make 394 g and thoroughly dissolved uniformly. The compositions of the cement additives and water-reducing agent are shown in Tables 2 to 5 below. A Hobart N-50 mixer equipped with a stainless steel beater (mixing blade) was used to mix the mortar. First, predetermined amounts of C and W were charged into a mixing vessel and mixed at first speed for 30 seconds. Then, S was added over 30 seconds and mixed at second speed for 30 seconds (the mortar composition was one of the formulations (1) to (4) shown in Table 1 below). After that, mixing was stopped, D was added, and mixing was continued for 30 seconds, after which the mortar adhering to the container wall was scraped off for 15 seconds, and the mixture was left to stand for 1 minute and 45 seconds. Mixing was then completed at second speed for another minute, and the mortar was transferred from the mixing container to a 1 L polyethylene container.

[0112] <Measurement of compressive strength> After mixing the mortar, compressive strength test samples were prepared, and compressive strength was measured under the following conditions. The measurement results (Examples (1) to (33) and Comparative Examples (1) to (40)) are shown in Tables 2 to 5 below. Specimen preparation: 50 mm x 100 mm Specimen curing (room temperature curing): Temperature 20°C, humidity 50%, constant temperature and humidity air curing for 24 hours Specimen polishing: Specimen surface polishing (using a specimen polishing finishing machine) Compressive strength measurement: Automatic compressive strength measuring instrument (manufactured by Mayekawa Manufacturing Co., Ltd.)

[0113]

[0114]

[0115]

[0116]

[0117] As shown in Table 2, when the one-day compressive strength of Comparative Example (1) is taken as 100%, the one-day compressive strength ratio of Example (1), in which a cement additive containing polyamine compound (A1) was used in a carbon dioxide-containing formulation (2), was 123%, demonstrating a strength improvement effect equivalent to 123% - 100% = 23%. Meanwhile, the strength improvement effect attributable to the carbon dioxide used in Example (1) is 103% in terms of the one-day compressive strength ratio, as shown in Comparative Example (2), and the strength improvement effect attributable to the polyamine compound (A1) used in Example (1) is 100% in terms of the one-day compressive strength ratio, as shown in Comparative Example (5). The simple sum of these effects is (103% + 100%) - 100% = 3%. Therefore, in Example (1), a significant synergistic effect of strength improvement (a remarkable increase from 3% to 23%) is observed by using polyamine compound (A1) in a cement composition for carbon dioxide fixation. Similarly, significant synergistic effects of strength improvement are observed in the other examples.

[0118] The above test results newly demonstrated that the cement additive of the present invention increases the strength of carbon dioxide fixation concrete.

Claims

1. A cement additive for use in a cement composition for carbon dioxide fixation, the cement additive being represented by the following formula (1): (In the formula, R １ , R ２ , R ３ , R ４ , R ５ , R ６ are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 or more carbon atoms. n and m are the same or different and represent an integer of 0 or more, provided that the number of nitrogen atoms contained in formula (1) is 2 to 6. x1 and x2 are the same or different and represent an integer of 0 or more. P is the same or different and represents a hydrogen atom, or a structural unit having another amino group due to branching. A cement additive comprising a compound represented by the formula (I) and / or a polyamine compound (A1) which is a heterocyclic polyamine.

2. The cement additive according to claim 1, wherein the molecular weight of the polyamine compound (A1) is 50 to 1,000.

3. A cement additive according to claim 1 or 2, further comprising an alkanolamine compound (B) and / or an alkylene glycol-containing compound (C), wherein the compound (C) has a structure in which 5 moles or more of alkylene oxide are added to 1 mole of a polyhydric alcohol or polyamine, and has a weight-average molecular weight of greater than 3,000.

4. The cement additive according to claim 3, wherein the alkanolamine compound (B) is at least one selected from the group consisting of monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, methylethanolamine, methylisopropanolamine, methyldiethanolamine, methyldiisopropanolamine, diethanolisopropanolamine, diisopropanolethanolamine, tetrahydroxyethylethylenediamine, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, and tris(2-hydroxybutyl)amine.

5. A cement additive according to claim 3 or 4, wherein the alkylene glycol-containing compound (C) is at least one selected from the group consisting of polyalkylene glycols, polymers having structural units derived from monomers in which alkylene oxide is added to unsaturated carboxylic acids, alkylene oxide adducts of polyhydric alcohols, polymers having structural units derived from monomers in which alkylene oxide is added to unsaturated alcohols, and alkylene oxide adducts of active hydrogens bonded to amino groups of polyalkyleneimines.

6. The alkylene glycol-containing compound (C) is selected from the group consisting of polyethylene glycol, polypropylene glycol, polymers having structural units derived from alkylene oxide adducts of methacrylic acid, alkylene oxide adducts of sorbitol, alkylene oxide adducts of neopentyl glycol, alkylene oxide adducts of pentanediol, alkylene oxide adducts of butanediol, alkylene oxide adducts of glycerin, polymers having structural units derived from alkylene oxide adducts of vinyl alcohol, polymers having structural units derived from alkylene oxide adducts of allyl alcohol, and alkylene oxide adducts of methallyl alcohol. The cement additive according to any one of claims 3 to 5, which is at least one selected from the group consisting of polymers having structural units derived from a silyl adduct, polymers having structural units derived from an alkylene oxide adduct of butenyl alcohol, polymers having structural units derived from an alkylene oxide adduct of 3-methyl-3-butenyl alcohol, polymers having structural units derived from an alkylene oxide adduct of 3-methyl-2-butenyl alcohol, polymers having structural units derived from an alkylene oxide adduct of 2-methyl-3-butenyl alcohol, and alkylene oxide adducts of active hydrogens bonded to amino groups of polyethyleneimine.

7. The cement additive according to any one of claims 3 to 6, wherein the total content of the alkanolamine compound (B) and the alkylene glycol-containing compound (C) is 1 to 500 mass% relative to 100 mass% of the polyamine compound (A1).

8. A cement additive according to any one of claims 3 to 7, wherein the content of the alkanolamine compound (B) is 0.5 to 250 mass% relative to 100 mass% of the polyamine compound (A1).

9. A cement additive according to any one of claims 3 to 8, wherein the content of the alkylene glycol-containing compound (C) is 0.5 to 250 mass% relative to 100 mass% of the polyamine compound (A1).

10. A method for improving the strength of carbon dioxide-immobilized concrete, the method comprising the step of adding a polyamine compound (A2) having two or more nitrogen atoms to a cement composition for immobilizing carbon dioxide.

11. The following formula (1): (In the formula, R １ , R ２ , R ３ , R ４ , R ５ , R ６ are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 or more carbon atoms. n and m are the same or different and represent an integer of 0 or more. However, the number of nitrogen atoms contained in formula (1) is 2 to 6. x1 and x2 are the same or different and represent an integer of 0 or more. P is the same or different and represents a hydrogen atom, or a structural unit having another amino group due to branching. Concrete containing a compound represented by the formula (I) and / or a polyamine compound (A1) which is a heterocyclic polyamine, and in which 0.01 to 30% by mass of carbon dioxide is fixed relative to 100% by mass of cement.

12. A method for producing carbon dioxide-fixed concrete, comprising the step of mixing the cement additive according to any one of claims 1 to 9, cement, and carbon dioxide, wherein the mixing ratio of the carbon dioxide is 0.01 to 30 mass% relative to 100 mass% of cement.

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